Spatial Patterns of Sea Level Variability Associated with Natural Internal Climate Modes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Weiqing; Meehl, Gerald A.; Stammer, Detlef

Sea level rise (SLR) can exert significant stress on highly populated coastal societies and low-lying island countries around the world. Because of this, there is huge societal demand for improved decadal predictions and future projections of SLR, particularly on a local scale along coastlines. Regionally, sea level variations can deviate considerably from the global mean due to various geophysical processes. These include changes of ocean circulations, which partially can be attributed to natural, internal modes of variability in the complex Earth’s climate system. Anthropogenic influence may also contribute to regional sea level variations. Separating the effects of natural climate modesmore » and anthropogenic forcing, however, remains a challenge and requires identification of the imprint of specific climate modes in observed sea level change patterns. In this article, we review our current state of knowledge about spatial patterns of sea level variability associated with natural climate modes on interannual-to-multidecadal timescales, with particular focus on decadal-to-multidecadal variability. Relevant climate modes and our current state of understanding their associated sea level patterns and driving mechanisms are elaborated separately for the Pacific, the Indian, the Atlantic, and the Arctic and Southern Oceans. We also discuss the issues, challenges and future outlooks for understanding the regional sea level patterns associated with climate modes. Effects of these internal modes have to be taken into account in order to achieve more reliable near-term predictions and future projections of regional SLR.« less

Spatial Patterns of Sea Level Variability Associated with Natural Internal Climate Modes

DOE PAGES

Han, Weiqing; Meehl, Gerald A.; Stammer, Detlef; ...

2016-10-04

Sea level rise (SLR) can exert significant stress on highly populated coastal societies and low-lying island countries around the world. Because of this, there is huge societal demand for improved decadal predictions and future projections of SLR, particularly on a local scale along coastlines. Regionally, sea level variations can deviate considerably from the global mean due to various geophysical processes. These include changes of ocean circulations, which partially can be attributed to natural, internal modes of variability in the complex Earth’s climate system. Anthropogenic influence may also contribute to regional sea level variations. Separating the effects of natural climate modesmore » and anthropogenic forcing, however, remains a challenge and requires identification of the imprint of specific climate modes in observed sea level change patterns. In this article, we review our current state of knowledge about spatial patterns of sea level variability associated with natural climate modes on interannual-to-multidecadal timescales, with particular focus on decadal-to-multidecadal variability. Relevant climate modes and our current state of understanding their associated sea level patterns and driving mechanisms are elaborated separately for the Pacific, the Indian, the Atlantic, and the Arctic and Southern Oceans. We also discuss the issues, challenges and future outlooks for understanding the regional sea level patterns associated with climate modes. Effects of these internal modes have to be taken into account in order to achieve more reliable near-term predictions and future projections of regional SLR.« less

Spatial Patterns of Sea Level Variability Associated with Natural Internal Climate Modes

NASA Astrophysics Data System (ADS)

Han, Weiqing; Meehl, Gerald A.; Stammer, Detlef; Hu, Aixue; Hamlington, Benjamin; Kenigson, Jessica; Palanisamy, Hindumathi; Thompson, Philip

2017-01-01

Sea level rise (SLR) can exert significant stress on highly populated coastal societies and low-lying island countries around the world. Because of this, there is huge societal demand for improved decadal predictions and future projections of SLR, particularly on a local scale along coastlines. Regionally, sea level variations can deviate considerably from the global mean due to various geophysical processes. These include changes of ocean circulations, which partially can be attributed to natural, internal modes of variability in the complex Earth's climate system. Anthropogenic influence may also contribute to regional sea level variations. Separating the effects of natural climate modes and anthropogenic forcing, however, remains a challenge and requires identification of the imprint of specific climate modes in observed sea level change patterns. In this paper, we review our current state of knowledge about spatial patterns of sea level variability associated with natural climate modes on interannual-to-multidecadal timescales, with particular focus on decadal-to-multidecadal variability. Relevant climate modes and our current state of understanding their associated sea level patterns and driving mechanisms are elaborated separately for the Pacific, the Indian, the Atlantic, and the Arctic and Southern Oceans. We also discuss the issues, challenges and future outlooks for understanding the regional sea level patterns associated with climate modes. Effects of these internal modes have to be taken into account in order to achieve more reliable near-term predictions and future projections of regional SLR.

Polar ice-sheet contributions to sea level during past warm periods

NASA Astrophysics Data System (ADS)

Dutton, A.

2015-12-01

Recent sea-level rise has been dominated by thermal expansion and glacier loss, but the contribution from mass loss from the Greenland and Antarctic ice sheets is expected to exceed other contributions under future sustained warming. Due to limitations of existing ice sheet models and the lack of relevant analogues in the historical record, projecting the timing and magnitude of polar ice sheet mass loss in the future remains challenging. One approach to improving our understanding of how polar ice-sheet retreat will unfold is to integrate observations and models of sea level, ice sheets, and climate during past intervals of warmth when the polar ice sheets contributed to higher sea levels. A recent review evaluated the evidence of polar ice sheet mass loss during several warm periods, including interglacials during the mid-Pliocene warm period, Marine Isotope Stage (MIS) 11, 5e (Last Interglacial), and 1 (Holocene). Sea-level benchmarks of ice-sheet retreat during the first of these three periods, when global mean climate was ~1 to 3 deg. C warmer than preindustrial, are useful for understanding the long-term potential for future sea-level rise. Despite existing uncertainties in these reconstructions, it is clear that our present climate is warming to a level associated with significant polar ice-sheet loss in the past, resulting in a conservative estimate for a global mean sea-level rise of 6 meters above present (or more). This presentation will focus on identifying the approaches that have yielded significant advances in terms of past sea level and ice sheet reconstruction as well as outstanding challenges. A key element of recent advances in sea-level reconstructions is the ability to recognize and quantify the imprint of geophysical processes, such as glacial isostatic adjustment (GIA) and dynamic topography, that lead to significant spatial variability in sea level reconstructions. Identifying specific ice-sheet sources that contributed to higher sea levels is a challenge that is currently hindered by limited field evidence at high latitudes. Finally, I will explore the concept of how increasing the quantity and quality of paleo sea level and ice sheet reconstructions can lead to improved quantification of contemporary changes in ice sheets and sea level.

Sea level rise from the Greenland Ice Sheet during the Eemian interglacial: Review of previous work with focus on the surface mass balance

NASA Astrophysics Data System (ADS)

Plach, Andreas; Hestnes Nisancioglu, Kerim

2016-04-01

The contribution from the Greenland Ice Sheet (GIS) to the global sea level rise during the Eemian interglacial (about 125,000 year ago) was the focus of many studies in the past. A main reason for the interest in this period is the considerable warmer climate during the Eemian which is often seen as an equivalent for possible future climate conditions. Simulated sea level rise during the Eemian can therefore be used to better understand a possible future sea level rise. The most recent assessment report of the Intergovernmental Panel on Climate Change (IPCC AR5) gives an overview of several studies and discusses the possible implications for a future sea level rise. The report also reveals the big differences between these studies in terms of simulated GIS extent and corresponding sea level rise. The present study gives a more exhaustive review of previous work discussing sea level rise from the GIS during the Eemian interglacial. The smallest extents of the GIS simulated by various authors are shown and summarized. A focus is thereby given to the methods used to calculate the surface mass balance. A hypothesis of the present work is that the varying results of the previous studies can largely be explained due to the various methods used to calculate the surface mass balance. In addition, as a first step for future work, the surface mass balance of the GIS for a proxy-data derived forcing ("index method") and a direct forcing with a General Circulation Model (GCM) are shown and discussed.

Projecting future sea level

USGS Publications Warehouse

Cayan, Daniel R.; Bromirski, Peter; Hayhoe, Katharine; Tyree, Mary; Dettinger, Mike; Flick, Reinhard

2006-01-01

California’s coastal observations and global model projections indicate that California’s open coast and estuaries will experience increasing sea levels over the next century. Sea level rise has affected much of the coast of California, including the Southern California coast, the Central California open coast, and the San Francisco Bay and upper estuary. These trends, quantified from a small set of California tide gages, have ranged from 10–20 centimeters (cm) (3.9–7.9 inches) per century, quite similar to that estimated for global mean sea level. So far, there is little evidence that the rate of rise has accelerated, and the rate of rise at California tide gages has actually flattened since 1980, but projections suggest substantial sea level rise may occur over the next century. Climate change simulations project a substantial rate of global sea level rise over the next century due to thermal expansion as the oceans warm and runoff from melting land-based snow and ice accelerates. Sea level rise projected from the models increases with the amount of warming. Relative to sea levels in 2000, by the 2070–2099 period, sea level rise projections range from 11–54 cm (4.3–21 in) for simulations following the lower (B1) greenhouse gas (GHG) emissions scenario, from 14–61 cm (5.5–24 in) for the middle-upper (A2) emission scenario, and from 17–72 cm (6.7–28 in) for the highest (A1fi) scenario. In addition to relatively steady secular trends, sea levels along the California coast undergo shorter period variability above or below predicted tide levels and changes associated with long-term trends. These variations are caused by weather events and by seasonal to decadal climate fluctuations over the Pacific Ocean that in turn affect the Pacific coast. Highest coastal sea levels have occurred when winter storms and Pacific climate disturbances, such as El Niño, have coincided with high astronomical tides. This study considers a range of projected future global sea level rises in examining possible impacts at California coastal and estuarine stations. Two climate models and three scenarios considered in this scenarios study provide a set of possible future weather and short-period climate fluctuations, and a range of potential long-term sea level rise values. A range of mean sea level rise was considered in combination with weather and El Niño fluctuations extracted from two global climate models and two GHG emissions scenarios. The mean sea level rise values, determined from a survey of several climate models, range from approximately 10–80 cm (3.9–31 in) between 2000 and 2100. The middle to higher end of this range would substantially exceed the historical rate of sea level rise of 15–20 cm (5.9–7.9 in)per century observed at San Francisco and San Diego during the last 100 years. Gradual sea level rise progressively worsens the impacts of high tides and the surge and waves associated with storms. The potential for impacts of future sea level rise was assessed from the occurrence of hourly sea level extremes. The occurrence of extreme events follows a sharply escalating pattern as the magnitude of future sea level rise increases. The confluence of Low barometric pressures from storms and the presence large waves at the same time substantially increases the likelihood of high, damaging sea levels along the California coast. Similarly, astronomical tides and disturbances in sea level that are caused by weather and climate fluctuations are x transmitted into the San Francisco Bay and Delta, and on into the lower reaches of the Sacramento River. In addition to elevating Bay and Delta sea levels directly through inverse barometer and wind effects, storms may generate heavy precipitation and high fresh water runoff and cause floods in the Sacramento/San Joaquin Delta, increasing the potential for inundation of levees and other structures. There may also be increased risk of levee failure due to the hydraulics and geometry of these structures. Rising sea levels from climate change will increase the frequency and duration of extreme high water levels, causing historical coastal and San Francisco Bay/Delta structure design criteria to be exceeded.

Future sea level rise constrained by observations and long-term commitment.

PubMed

Mengel, Matthias; Levermann, Anders; Frieler, Katja; Robinson, Alexander; Marzeion, Ben; Winkelmann, Ricarda

2016-03-08

Sea level has been steadily rising over the past century, predominantly due to anthropogenic climate change. The rate of sea level rise will keep increasing with continued global warming, and, even if temperatures are stabilized through the phasing out of greenhouse gas emissions, sea level is still expected to rise for centuries. This will affect coastal areas worldwide, and robust projections are needed to assess mitigation options and guide adaptation measures. Here we combine the equilibrium response of the main sea level rise contributions with their last century's observed contribution to constrain projections of future sea level rise. Our model is calibrated to a set of observations for each contribution, and the observational and climate uncertainties are combined to produce uncertainty ranges for 21st century sea level rise. We project anthropogenic sea level rise of 28-56 cm, 37-77 cm, and 57-131 cm in 2100 for the greenhouse gas concentration scenarios RCP26, RCP45, and RCP85, respectively. Our uncertainty ranges for total sea level rise overlap with the process-based estimates of the Intergovernmental Panel on Climate Change. The "constrained extrapolation" approach generalizes earlier global semiempirical models and may therefore lead to a better understanding of the discrepancies with process-based projections.

Future sea level rise constrained by observations and long-term commitment

PubMed Central

Mengel, Matthias; Levermann, Anders; Frieler, Katja; Robinson, Alexander; Marzeion, Ben; Winkelmann, Ricarda

2016-01-01

Sea level has been steadily rising over the past century, predominantly due to anthropogenic climate change. The rate of sea level rise will keep increasing with continued global warming, and, even if temperatures are stabilized through the phasing out of greenhouse gas emissions, sea level is still expected to rise for centuries. This will affect coastal areas worldwide, and robust projections are needed to assess mitigation options and guide adaptation measures. Here we combine the equilibrium response of the main sea level rise contributions with their last century's observed contribution to constrain projections of future sea level rise. Our model is calibrated to a set of observations for each contribution, and the observational and climate uncertainties are combined to produce uncertainty ranges for 21st century sea level rise. We project anthropogenic sea level rise of 28–56 cm, 37–77 cm, and 57–131 cm in 2100 for the greenhouse gas concentration scenarios RCP26, RCP45, and RCP85, respectively. Our uncertainty ranges for total sea level rise overlap with the process-based estimates of the Intergovernmental Panel on Climate Change. The “constrained extrapolation” approach generalizes earlier global semiempirical models and may therefore lead to a better understanding of the discrepancies with process-based projections. PMID:26903648

Coastline Mapping and Cultural Review to Predict Sea Level Rise Impact on Hawaiian Archeological Sites

NASA Astrophysics Data System (ADS)

Clinton, J.

2017-12-01

Much of Hawaii's history is recorded in archeological sites. Researchers and cultural practitioners have been studying and reconstructing significant archeological sites for generations. Climate change, and more specifically, sea level rise may threaten these sites. Our research records current sea levels and then projects possible consequences to these cultural monuments due to sea level rise. In this mixed methods study, research scientists, cultural practitioners, and secondary students use plane-table mapping techniques to create maps of coastlines and historic sites. Students compare historical records to these maps, analyze current sea level rise trends, and calculate future sea levels. They also gather data through interviews with community experts and kupuna (elders). If climate change continues at projected rates, some historic sites will be in danger of negative impact due to sea level rise. Knowing projected sea levels at specific sites allows for preventative action and contributes to raised awareness of the impacts of climate change to the Hawaiian Islands. Students will share results with the community and governmental agencies in hopes of inspiring action to minimize climate change. It will take collaboration between scientists and cultural communities to inspire future action on climate change.

Sea-level feedback lowers projections of future Antarctic Ice-Sheet mass loss

PubMed Central

Gomez, Natalya; Pollard, David; Holland, David

2015-01-01

The stability of marine sectors of the Antarctic Ice Sheet (AIS) in a warming climate has been identified as the largest source of uncertainty in projections of future sea-level rise. Sea-level fall near the grounding line of a retreating marine ice sheet has a stabilizing influence on the ice sheets, and previous studies have established the importance of this feedback on ice age AIS evolution. Here we use a coupled ice sheet–sea-level model to investigate the impact of the feedback mechanism on future AIS retreat over centennial and millennial timescales for a range of emission scenarios. We show that the combination of bedrock uplift and sea-surface drop associated with ice-sheet retreat significantly reduces AIS mass loss relative to a simulation without these effects included. Sensitivity analyses show that the stabilization tends to be greatest for lower emission scenarios and Earth models characterized by a thin elastic lithosphere and low-viscosity upper mantle, as is the case for West Antarctica. PMID:26554381

Future probabilities of coastal floods in Finland

NASA Astrophysics Data System (ADS)

Pellikka, Havu; Leijala, Ulpu; Johansson, Milla M.; Leinonen, Katri; Kahma, Kimmo K.

2018-04-01

Coastal planning requires detailed knowledge of future flooding risks, and effective planning must consider both short-term sea level variations and the long-term trend. We calculate distributions that combine short- and long-term effects to provide estimates of flood probabilities in 2050 and 2100 on the Finnish coast in the Baltic Sea. Our distributions of short-term sea level variations are based on 46 years (1971-2016) of observations from the 13 Finnish tide gauges. The long-term scenarios of mean sea level combine postglacial land uplift, regionally adjusted scenarios of global sea level rise, and the effect of changes in the wind climate. The results predict that flooding risks will clearly increase by 2100 in the Gulf of Finland and the Bothnian Sea, while only a small increase or no change compared to present-day conditions is expected in the Bothnian Bay, where the land uplift is stronger.

Visualizing Sea Level Rise with Augmented Reality

NASA Astrophysics Data System (ADS)

Kintisch, E. S.

2013-12-01

Looking Glass is an application on the iPhone that visualizes in 3-D future scenarios of sea level rise, overlaid on live camera imagery in situ. Using a technology known as augmented reality, the app allows a layperson user to explore various scenarios of sea level rise using a visual interface. Then the user can see, in an immersive, dynamic way, how those scenarios would affect a real place. The first part of the experience activates users' cognitive, quantitative thinking process, teaching them how global sea level rise, tides and storm surge contribute to flooding; the second allows an emotional response to a striking visual depiction of possible future catastrophe. This project represents a partnership between a science journalist, MIT, and the Rhode Island School of Design, and the talk will touch on lessons this projects provides on structuring and executing such multidisciplinary efforts on future design projects.

Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations.

PubMed

Roshan, Gholamreza; Moghbel, Masumeh; Grab, Stefan

2012-12-12

The rapid rise of Caspian Sea water level (about 2.25 meters since 1978) has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was simulated. Variations in environmental parameters such as temperature, precipitation, evaporation, atmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for both past (1951-2006) and future (2025-2100) time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software (version 5.3). The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site) has increased by ca. 0.17°C per decade under the impacts of atmospheric carbon dioxide changes (r=0.21). The Caspian Sea water level has increased by ca. +36cm per decade (r=0.82) between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64°C and precipitation will decrease by ca. 10% (182 mm) over the Caspian Sea, whilst in the Volga river basin, temperatures are projected to increase by ca. 4.78°C and precipitation increase by ca. 12% (58 mm) by the year 2100. Finally, statistical modeling of the Caspian Sea water levels project future water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively.

Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations

PubMed Central

2012-01-01

The rapid rise of Caspian Sea water level (about 2.25 meters since 1978) has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was simulated. Variations in environmental parameters such as temperature, precipitation, evaporation, atmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for both past (1951-2006) and future (2025-2100) time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software (version 5.3). The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site) has increased by ca. 0.17°C per decade under the impacts of atmospheric carbon dioxide changes (r=0.21). The Caspian Sea water level has increased by ca. +36cm per decade (r=0.82) between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64°C and precipitation will decrease by ca. 10% (182 mm) over the Caspian Sea, whilst in the Volga river basin, temperatures are projected to increase by ca. 4.78°C and precipitation increase by ca. 12% (58 mm) by the year 2100. Finally, statistical modeling of the Caspian Sea water levels project future water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively. PMID:23369617

Characterization of extreme sea level at the European coast

NASA Astrophysics Data System (ADS)

Elizalde, Alberto; Jorda, Gabriel; Mathis, Moritz; Mikolajewicz, Uwe

2015-04-01

Extreme high sea levels arise as a combination of storm surges and particular high tides events. Future climate simulations not only project changes in the atmospheric circulation, which induces changes in the wind conditions, but also an increase in the global mean sea level by thermal expansion and ice melting. Such changes increase the risk of coastal flooding, which represents a possible hazard for human activities. Therefore, it is important to investigate the pattern of sea level variability and long-term trends at coastal areas. In order to analyze further extreme sea level events at the European coast in the future climate projections, a new setup for the global ocean model MPIOM coupled with the regional atmosphere model REMO is prepared. The MPIOM irregular grid has enhanced resolution in the European region to resolve the North and the Mediterranean Seas (up to 11 x 11 km at the North Sea). The ocean model includes as well the full luni-solar ephemeridic tidal potential for tides simulation. To simulate the air-sea interaction, the regional atmospheric model REMO is interactively coupled to the ocean model over Europe. Such region corresponds to the EuroCORDEX domain with a 50 x 50 km resolution. Besides the standard fluxes of heat, mass (freshwater), momentum and turbulent energy input, the ocean model is also forced with sea level pressure, in order to be able to capture the full variation of sea level. The hydrological budget within the study domain is closed using a hydrological discharge model. With this model, simulations for present climate and future climate scenarios are carried out to study transient changes on the sea level and extreme events. As a first step, two simulations (coupled and uncoupled ocean) driven by reanalysis data (ERA40) have been conducted. They are used as reference runs to evaluate the climate projection simulations. For selected locations at the coast side, time series of sea level are separated on its different components: tides, short time atmospheric process influence (1-30 days), seasonal cycle and interannual variability. Every sea level component is statistically compared with data from local tide gauges.

Estuarine Response to River Flow and Sea-Level Rise under Future Climate Change and Human Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Zhaoqing; Wang, Taiping; Voisin, Nathalie

Understanding the response of river flow and estuarine hydrodynamics to climate change, land-use/land-cover change (LULC), and sea-level rise is essential to managing water resources and stress on living organisms under these changing conditions. This paper presents a modeling study using a watershed hydrology model and an estuarine hydrodynamic model, in a one-way coupling, to investigate the estuarine hydrodynamic response to sea-level rise and change in river flow due to the effect of future climate and LULC changes in the Snohomish River estuary, Washington, USA. A set of hydrodynamic variables, including salinity intrusion points, average water depth, and salinity of themore » inundated area, were used to quantify the estuarine response to river flow and sea-level rise. Model results suggest that salinity intrusion points in the Snohomish River estuary and the average salinity of the inundated areas are a nonlinear function of river flow, although the average water depth in the inundated area is approximately linear with river flow. Future climate changes will shift salinity intrusion points further upstream under low flow conditions and further downstream under high flow conditions. In contrast, under the future LULC change scenario, the salinity intrusion point will shift downstream under both low and high flow conditions, compared to present conditions. The model results also suggest that the average water depth in the inundated areas increases linearly with sea-level rise but at a slower rate, and the average salinity in the inundated areas increases linearly with sea-level rise; however, the response of salinity intrusion points in the river to sea-level rise is strongly nonlinear.« less

Coastal sensitivity to sea level rise : a focus on the mid-atlantic region

DOT National Transportation Integrated Search

2009-01-15

The focus of this product is to identify and review the potential impacts of future sea-level rise based on present scientific understanding. To do so, this product evaluates : several aspects of sea-level rise impacts to the natural environment and ...

Minimum and Maximum Potential Contributions to Future Sea Level Rise from Polar Ice Sheets

NASA Astrophysics Data System (ADS)

Deconto, R. M.; Pollard, D.

2017-12-01

New climate and ice-sheet modeling, calibrated to past changes in sea-level, is painting a stark picture of the future fate of the great polar ice sheets if greenhouse gas emissions continue unabated. This is especially true for Antarctica, where a substantial fraction of the ice sheet rests on bedrock more than 500-meters below sea level. Here, we explore the sensitivity of the polar ice sheets to a warming atmosphere and ocean under a range of future greenhouse gas emissions scenarios. The ice sheet-climate-ocean model used here considers time-evolving changes in surface mass balance and sub-ice oceanic melting, ice deformation, grounding line retreat on reverse-sloped bedrock (Marine Ice Sheet Instability), and newly added processes including hydrofracturing of ice shelves in response to surface meltwater and rain, and structural collapse of thick, marine-terminating ice margins with tall ice-cliff faces (Marine Ice Cliff Instability). The simulations improve on previous work by using 1) improved atmospheric forcing from a Regional Climate Model and 2) a much wider range of model physical parameters within the bounds of modern observations of ice dynamical processes (particularly calving rates) and paleo constraints on past ice-sheet response to warming. Approaches to more precisely define the climatic thresholds capable of triggering rapid and potentially irreversible ice-sheet retreat are also discussed, as is the potential for aggressive mitigation strategies like those discussed at the 2015 Paris Climate Conference (COP21) to substantially reduce the risk of extreme sea-level rise. These results, including physics that consider both ice deformation (creep) and calving (mechanical failure of marine terminating ice) expand on previously estimated limits of maximum rates of future sea level rise based solely on kinematic constraints of glacier flow. At the high end, the new results show the potential for more than 2m of global mean sea level rise by 2100, implying that physically plausible upper limits on future sea-level rise might need to be reconsidered.

Global Projection of Coastal Exposure Associated with Sea-level Rise beyond Tipping Points

NASA Astrophysics Data System (ADS)

Tawatari, R.; Miyazaki, C.; Iseri, Y.; Kiguchi, M.; Kanae, S.

2015-12-01

Sea-level rise due to global warming becomes a great matter of concern for global coastal area. Additionally, it has reported in fifth report of IPCC (Intergovernmental Panel on Climate Change) that deglaciation of Greenland ice sheet and Antarctic ice sheet would occur rapidly and enhance sea-level rise if temperature passes certain "Tipping point". In terms of projecting damage induced by sea-level rise globally, some previous studies focused on duration until mainly 2100. Furthermore long-term estimations on centuries to millennial climatic response of the ice sheets which are supposed to be triggered within this or next century would be also important to think about future climate and lifestyle in coastal . In this study, I estimated the long term sea-level which take into account the tipping points of Greenland ice sheet (1.4℃) as sum of 4 factors (thermal expansion, glacier and ice cap, Greenland ice sheet, Antarctic ice sheet). The sea-level follows 4 representative concentration pathways up to 3000 obtained through literature reviewing since there were limited available sea-level projections up to 3000. I also estimated a number of affected population lives in coastal area up to 3000 with using the estimated sea-level. The cost for damage, adaptation and mitigation would be also discussed. These estimations would be useful when decision-makers propose policies for construction of dikes and proposing mitigation plans for sustainable future. The result indicates there would be large and relatively rapid increases in both sea-level rise and coastal exposure if global mean temperature passes the tipping point of Greenland ice sheet. However the tipping points, melting rate and timescale of response are highly uncertain and still discussed among experts. Thus more precise and credible information is required for further accurate estimation of long-term sea-level rise and population exposure in the future.

The Wadden Sea in transition - consequences of sea level rise

NASA Astrophysics Data System (ADS)

Becherer, Johannes; Hofstede, Jacobus; Gräwe, Ulf; Purkiani, Kaveh; Schulz, Elisabeth; Burchard, Hans

2018-01-01

The impact of sea level rise (SLR) on the future morphological development of the Wadden Sea (North Sea) is investigated by means of extensive process-resolving numerical simulations. A new sediment and morphodynamic module was implemented in the well-established 3D circulation model GETM. A number of different validations are presented, ranging from an idealized 1D channel over a semi-idealized 2D Wadden Sea basin to a fully coupled realistic 40-year hindcast without morphological amplification of the Sylt-Rømøbight, a semi-enclosed subsystem of the Wadden Sea. Based on the results of the hindcast, four distinct future scenarios covering the period 2010-2100 are simulated. While these scenarios differ in the strength of SLR and wind forcing, they also account for an expected increase of tidal range over the coming century. The results of the future projections indicate a transition from a tidal-flat-dominated system toward a lagoon-like system, in which large fractions of the Sylt-Rømøbight will remain permanently covered by water. This has potentially dramatic implications for the unique ecosystem of the Wadden Sea. Although the simulations also predict an increased accumulation of sediment in the back-barrier basin, this accumulation is far too weak to compensate for the rise in mean sea level.

On the regional characteristics of past and future sea-level change (Invited)

NASA Astrophysics Data System (ADS)

Timmermann, A.; McGregor, S.

2010-12-01

Global sea-level rise due to the thermal expansion of the warming oceans and freshwater input from melting glaciers and ice-sheets is threatening to inundate low-lying islands and coast-lines worldwide. At present global mean sea level rises at 3.1 ± 0.7 mm/yr with an accelerating tendency. However, the magnitude of recent decadal sea-level trends varies greatly spatially attaining values of up to 10 mm/yr in some areas of the western tropical Pacific. Identifying the causes of recent regional sea-level trends and understanding the patterns of future projected sea-level change is of crucial importance. Using a wind-forced simplified dynamical ocean model, we show that the regional features of recent decadal and multidecadal sea-level trends in the tropical Indo-Pacific can be attributed to changes in the prevailing wind-regimes. Furthermore it is demonstrated that within an ensemble of ten state-of-the art coupled general circulation models, forced by increasing atmospheric CO2 concentrations over the next century, wind-induced re-distributions of upper-ocean water play a key role in establishing the spatial characteristics of projected regional sea-level rise. Wind-related changes in near- surface mass and heat convergence near the Solomon Islands, Tuvalu, Kiribati, the Cook Islands and French Polynesia oppose, but can not cancel the regional signal of global mean sea-level rise.

ISMIP6: Ice Sheet Model Intercomparison Project for CMIP6

NASA Technical Reports Server (NTRS)

Nowicki, S.

2015-01-01

ISMIP6 (Ice Sheet Model Intercomparison Project for CMIP6) targets the Cryosphere in a Changing Climate and the Future Sea Level Grand Challenges of the WCRP (World Climate Research Program). Primary goal is to provide future sea level contribution from the Greenland and Antarctic ice sheets, along with associated uncertainty. Secondary goal is to investigate feedback due to dynamic ice sheet models. Experiment design uses and augment the existing CMIP6 (Coupled Model Intercomparison Project Phase 6) DECK (Diagnosis, Evaluation, and Characterization of Klima) experiments. Additonal MIP (Model Intercomparison Project)- specific experiments will be designed for ISM (Ice Sheet Model). Effort builds on the Ice2sea, SeaRISE (Sea-level Response to Ice Sheet Evolution) and COMBINE (Comprehensive Modelling of the Earth System for Better Climate Prediction and Projection) efforts.

Constraining Future Sea Level Rise Estimates from the Amundsen Sea Embayment, West Antarctica

NASA Astrophysics Data System (ADS)

Nias, I.; Cornford, S. L.; Edwards, T.; Gourmelen, N.; Payne, A. J.

2016-12-01

The Amundsen Sea Embayment (ASE) is the primary source of mass loss from the West Antarctic Ice Sheet. The catchment is particularly susceptible to grounding line retreat, because the ice sheet is grounded on bedrock that is below sea level and deepening towards its interior. Mass loss from the ASE ice streams, which include Pine Island, Thwaites and Smith glaciers, is a major uncertainty on future sea level rise, and understanding the dynamics of these ice streams is essential to constraining this uncertainty. The aim of this study is to construct a distribution of future ASE sea level contributions from an ensemble of ice sheet model simulations and observations of surface elevation change. A 284 member ensemble was performed using BISICLES, a vertically-integrated ice flow model with adaptive mesh refinement. Within the ensemble parameters associated with basal traction, ice rheology and sub-shelf melt rate were perturbed, and the effect of bed topography and sliding law were also investigated. Initially each configuration was run to 50 model years. Satellite observations of surface height change were then used within a Bayesian framework to assign likelihoods to each ensemble member. Simulations that better reproduced the current thinning patterns across the catchment were given a higher score. The resulting posterior distribution of sea level contributions is narrower than the prior distribution, although the central estimates of sea level rise are similar between the prior and posterior. The most extreme simulations were eliminated and the remaining ensemble members were extended to 200 years, using a simple melt rate forcing.

A Mediterranean coastal database for assessing the impacts of sea-level rise and associated hazards

NASA Astrophysics Data System (ADS)

Wolff, Claudia; Vafeidis, Athanasios T.; Muis, Sanne; Lincke, Daniel; Satta, Alessio; Lionello, Piero; Jimenez, Jose A.; Conte, Dario; Hinkel, Jochen

2018-03-01

We have developed a new coastal database for the Mediterranean basin that is intended for coastal impact and adaptation assessment to sea-level rise and associated hazards on a regional scale. The data structure of the database relies on a linear representation of the coast with associated spatial assessment units. Using information on coastal morphology, human settlements and administrative boundaries, we have divided the Mediterranean coast into 13 900 coastal assessment units. To these units we have spatially attributed 160 parameters on the characteristics of the natural and socio-economic subsystems, such as extreme sea levels, vertical land movement and number of people exposed to sea-level rise and extreme sea levels. The database contains information on current conditions and on plausible future changes that are essential drivers for future impacts, such as sea-level rise rates and socio-economic development. Besides its intended use in risk and impact assessment, we anticipate that the Mediterranean Coastal Database (MCD) constitutes a useful source of information for a wide range of coastal applications.

A Mediterranean coastal database for assessing the impacts of sea-level rise and associated hazards

PubMed Central

Wolff, Claudia; Vafeidis, Athanasios T.; Muis, Sanne; Lincke, Daniel; Satta, Alessio; Lionello, Piero; Jimenez, Jose A.; Conte, Dario; Hinkel, Jochen

2018-01-01

We have developed a new coastal database for the Mediterranean basin that is intended for coastal impact and adaptation assessment to sea-level rise and associated hazards on a regional scale. The data structure of the database relies on a linear representation of the coast with associated spatial assessment units. Using information on coastal morphology, human settlements and administrative boundaries, we have divided the Mediterranean coast into 13 900 coastal assessment units. To these units we have spatially attributed 160 parameters on the characteristics of the natural and socio-economic subsystems, such as extreme sea levels, vertical land movement and number of people exposed to sea-level rise and extreme sea levels. The database contains information on current conditions and on plausible future changes that are essential drivers for future impacts, such as sea-level rise rates and socio-economic development. Besides its intended use in risk and impact assessment, we anticipate that the Mediterranean Coastal Database (MCD) constitutes a useful source of information for a wide range of coastal applications. PMID:29583140

Historical Climate Change Impacts on the Hydrological Processes of the Ponto-Caspian Basin

NASA Astrophysics Data System (ADS)

Koriche, Sifan A.; Singarayer, Joy S.; Coe, Michael T.; Nandini, Sri; Prange, Matthias; Cloke, Hannah; Lunt, Dan

2017-04-01

The Ponto-Caspian basin is one of the largest basins globally, composed of a closed basin (Caspian Sea) and open basins connecting to the global ocean (Black and Azov Sea). Over the historical time period (1850-present) Caspian Sea levels have varied between -25 and -29mbsl (Arpe et al., 2012), resulting in considerable changes to the area of the lake (currently 371,000 km2). Given projections of future climate change and the importance of the Caspian Sea for fisheries, agriculture, and industry, it is vital to understand how sea levels may vary in the future. Hydrological models can be used to assess the impacts of climate change on hydrological processes for future forecasts. However, it is critical to first evaluate such models using observational data for the present and recent past, and to understand the key hydrological processes driving past changes in sea level. In this study, the Terrestrial Hydrological Model (THMB) (Coe, 2000, 2002) is applied and evaluated to investigate the hydrological processes of the Ponto-Caspian basin for the historical period 1900 to 2000. The model has been forced using observational reanalysis datasets (ERA-Interim, ERA-20) and historical climate model data outputs (from CESM and HadCM3 models) to investigate the variability in the Caspian Sea level and the major river discharges. We examine the differences produced by driving the hydrological model with reanalysis data or climate models. We evaluate the model performance compared to observational discharge measurements and Caspian Sea level data. Secondly, we investigated the sensitivity of historical Caspian Sea level variations to different aspects of climate changes to examine the most important processes involved over this time period.

Sea Extremes: Integrated impact assessment in coastal climate adaptation

NASA Astrophysics Data System (ADS)

Sorensen, Carlo; Knudsen, Per; Broge, Niels; Molgaard, Mads; Andersen, Ole

2016-04-01

We investigate effects of sea level rise and a change in precipitation pattern on coastal flooding hazards. Historic and present in situ and satellite data of water and groundwater levels, precipitation, vertical ground motion, geology, and geotechnical soil properties are combined with flood protection measures, topography, and infrastructure to provide a more complete picture of the water-related impact from climate change at an exposed coastal location. Results show that future sea extremes evaluated from extreme value statistics may, indeed, have a large impact. The integrated effects from future storm surges and other geo- and hydro-parameters need to be considered in order to provide for the best protection and mitigation efforts, however. Based on the results we present and discuss a simple conceptual model setup that can e.g. be used for 'translation' of regional sea level rise evidence and projections to concrete impact measures. This may be used by potentially affected stakeholders -often working in different sectors and across levels of governance, in a common appraisal of the challenges faced ahead. The model may also enter dynamic tools to evaluate local impact as sea level research advances and projections for the future are updated.

Modeling and Analysis of Sea-level Rise Impacts on Salinity in the Lower St. Johns River

NASA Astrophysics Data System (ADS)

Bacopoulos, P.

2015-12-01

There is deliberate attention being paid to studying sea-level rise impacts on the lower St. Johns River, a drowned coastal plain-type estuary with low topographic drive, located in northeastern Florida. One area of attention is salinity in the river, which influences the entire food web, including sea and marsh grasses, juvenile crustaceans and fishes, wading birds and migratory waterfowl, marine mammals and other predator animals. It is expected that elevated ocean levels will increase the salinity of the estuarine waters, leading to deleterious effects on dependent species of the river biology. The objective of the modeling and analysis was: 1) to establish baseline conditions of salinity for the lower St. Johns River; and 2) to examine future conditions of salinity, as impacted by sea-level rise. Establishing baseline conditions entailed validation of the model for present-day salinity in the lower St. Johns River via comparison to available data. Examining future conditions entailed application of the model for sea-level rise scenarios, with comparison to the baseline conditions, for evaluation of sea-level rise impacts on salinity. While the central focus was on the physics of sea-level rise impacts on salinity, some level of salinity-biological assessment was conducted to identify sea-level rise/salinity thresholds, as related to negatively impacting different species of the river biology.

Predicting the impact of tsunami in California under rising sea level

NASA Astrophysics Data System (ADS)

Dura, T.; Garner, A. J.; Weiss, R.; Kopp, R. E.; Horton, B.

2017-12-01

The flood hazard for the California coast depends not only on the magnitude, location, and rupture length of Alaska-Aleutian subduction zone earthquakes and their resultant tsunamis, but also on rising sea levels, which combine with tsunamis to produce overall flood levels. The magnitude of future sea-level rise remains uncertain even on the decadal scale, with future sea-level projections becoming even more uncertain at timeframes of a century or more. Earthquake statistics indicate that timeframes of ten thousand to one hundred thousand years are needed to capture rare, very large earthquakes. Because of the different timescales between reliable sea-level projections and earthquake distributions, simply combining the different probabilities in the context of a tsunami hazard assessment may be flawed. Here, we considered 15 earthquakes between Mw 8 to Mw 9.4 bound by -171oW and -140oW of the Alaska-Aleutian subduction zone. We employed 24 realizations at each magnitude with random epicenter locations and different fault length-to-width ratios, and simulated the tsunami evolution from these 360 earthquakes at each decade from the years 2000 to 2200. These simulations were then carried out for different sea-level-rise projections to analyze the future flood hazard for California. Looking at the flood levels at tide gauges, we found that the flood level simulated at, for example, the year 2100 (including respective sea-level change) is different from the flood level calculated by adding the flood for the year 2000 to the sea-level change prediction for the year 2100. This is consistent for all sea-level rise scenarios, and this difference in flood levels range between 5% and 12% for the larger half of the given magnitude interval. Focusing on flood levels at the tide gauge in the Port of Los Angeles, the most probable flood level (including all earthquake magnitudes) in the year 2000 was 5 cm. Depending on the sea-level predictions, in the year 2050 the most probable flood levels could rise to 20 to 30 cm, but increase significantly from 2100 to 2200 to between 0.5 m and 2.5 m. Aside from the significant increase in flood level, it should be noted that the range over which potential most probable flood levels can vary is significant and defines a tremendous challenge for long-term planning of hazard mitigating measures.

Understanding extreme sea levels for coastal impact and adaptation analysis

NASA Astrophysics Data System (ADS)

Wahl, T.; Haigh, I. D.; Nicholls, R. J.; Arns, A.; Hinkel, J.; Dangendorf, S.; Slangen, A.

2016-12-01

Coastal impact and adaptation assessments require detailed knowledge on extreme sea levels, because increasing damage due to extreme events, such as storm surges and tropical cyclones, is one of the major consequences of sea level rise and climate change. In fact, the IPCC has highlighted in its AR4 report that "societal impacts of sea level change primarily occur via the extreme levels rather than as a direct consequence of mean sea level changes". Over the last few decades, substantial research efforts have been directed towards improved understanding of past and future mean sea level; different scenarios were developed with process-based or semi-empirical models and used for coastal impact assessments at various spatial scales to guide coastal management and adaptation efforts. The uncertainties in future sea level rise are typically accounted for by analyzing the impacts associated with a range of scenarios leading to a vertical displacement of the distribution of extreme sea-levels. And indeed most regional and global studies find little or no evidence for changes in storminess with climate change, although there is still low confidence in the results. However, and much more importantly, there is still a limited understanding of present-day extreme sea-levels which is largely ignored in most impact and adaptation analyses. The two key uncertainties stem from: (1) numerical models that are used to generate long time series of extreme sea-levels. The bias of these models varies spatially and can reach values much larger than the expected sea level rise; but it can be accounted for in most regions making use of in-situ measurements; (2) Statistical models used for determining present-day extreme sea-level exceedance probabilities. There is no universally accepted approach to obtain such values for flood risk assessments and while substantial research has explored inter-model uncertainties for mean sea level, we explore here, for the first time, inter-model uncertainties for extreme sea-levels at large spatial scales and compare them to the uncertainties in mean sea level projections.

Future sea-level rise in the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Galassi, Gaia; Spada, Giorgio

2014-05-01

Secular sea level variations in the Mediterranean Sea are the result of a number of processes characterized by distinct time scales and spatial patterns. Here we predict the future sea level variations in the Mediterranean Sea to year 2050 combining the contributions from terrestrial ice melt (TIM), glacial isostatic adjustment (GIA), and the ocean response (OR) that includes the thermal expansion and the ocean circulation contributions. The three contributions are characterized by comparable magnitudes but distinctly different sea-level fingerprints across the Mediterranean basin. The TIM component of future sea-level rise is taken from Spada et al. (2013) and it is mainly driven by the melt of small glaciers and ice caps and by the dynamic ice loss from Antarctica. The sea-level fingerprint associated with GIA is studied using two distinct models available from the literature: ICE-5G(VM2) (Peltier, 2004) and the ice model progressively developed at the Research School of Earth Sciences (RSES) of the National Australian University (KL05) (see Fleming and Lambeck, 2004 and references therein). Both the GIA and the TIM sea-level predictions have been obtained with the aid of the SELEN program (Spada and Stocchi, 2007). The spatially-averaged OR component, which includes thermosteric and halosteric sea-level variations, recently obtained using a regional coupled ocean-atmosphere model (Carillo et al., 2012), vary between 2 and 7 cm according to scenarios adopted (EA1B and EA1B2, see Meehl at al., 2007). Since the sea-level variations associated with TIM mainly result from the gravitational interactions between the cryosphere components, the oceans and the solid Earth, and long-wavelength rotational variations, they are characterized by a very smooth global pattern and by a marked zonal symmetry reflecting the dipole geometry of the ice sources. Since the Mediterranean Sea is located in the intermediate far-field of major ice sources, TIM sea-level changes have sub-eustatic values (i.e. they do not exceed the global average) and show little (but still significant) variations across the basin associated with the subsidence driven by the meltwater load. For year 2050, TIM calculations predict a sea-level rise of ~10 and ~30 cm for the mid range and the high end scenarios, respectively. Mainly because of the distinct mantle viscosity profiles adopted in ICE-5G(VM2) and KL05, the GIA patterns differ significantly and, in contrast with the TIM fingerprint, are both characterized by strong variations across the Mediterranean Sea, showing maximum values in the bulk of the basin. For the OR component, a significant geographical variation is observed across the Mediterranean sub-basins, corresponding to different Atlantic boundary conditionsAccording to this study, the total future sea-level rise for year 2050 will reach maximum values for the extreme scenario (hig-hend prediction for TIM, KL05 for GIA and EA1B2 for OR) of ˜ 27 cm in average with peak of ˜ 30 cm in the central sub-basins. Our results show that when these three components of future sea-level rise are simultaneously considered, the spatial variability is enhanced because of the neatly distinct geometry of the three fingerprints. References: Carillo, A., Sannino, G., Artale, V., Ruti, P., Calmanti, S., DellAquila, A., 2012, Clim. Dyn. 39 (9-10), 2167-2184; Fleming, K. and Lambeck, K., 2004, Quat. Sci. Rev. 23 (9-10), 1053-1077; Meehl, G.A., and 11 others, 2007, in Climate Change 2007: The Physical Science Basis, Cambridge University Press; Peltier W.R., 2004, Annu. Rev. Earth Pl. Sc., 32, 111-149; Spada, G. and Stocchi, P., 2007, Comput. and Geosci., 33(4), 538-562; Spada G., Bamber J. L., Hurkmans R. T. W. L., 2013, Geophys. Res. Lett., 1-5, 40.

Impacts of representing sea-level rise uncertainty on future flood risks: An example from San Francisco Bay

PubMed Central

Oddo, Perry C.; Keller, Klaus

2017-01-01

Rising sea levels increase the probability of future coastal flooding. Many decision-makers use risk analyses to inform the design of sea-level rise (SLR) adaptation strategies. These analyses are often silent on potentially relevant uncertainties. For example, some previous risk analyses use the expected, best, or large quantile (i.e., 90%) estimate of future SLR. Here, we use a case study to quantify and illustrate how neglecting SLR uncertainties can bias risk projections. Specifically, we focus on the future 100-yr (1% annual exceedance probability) coastal flood height (storm surge including SLR) in the year 2100 in the San Francisco Bay area. We find that accounting for uncertainty in future SLR increases the return level (the height associated with a probability of occurrence) by half a meter from roughly 2.2 to 2.7 m, compared to using the mean sea-level projection. Accounting for this uncertainty also changes the shape of the relationship between the return period (the inverse probability that an event of interest will occur) and the return level. For instance, incorporating uncertainties shortens the return period associated with the 2.2 m return level from a 100-yr to roughly a 7-yr return period (∼15% probability). Additionally, accounting for this uncertainty doubles the area at risk of flooding (the area to be flooded under a certain height; e.g., the 100-yr flood height) in San Francisco. These results indicate that the method of accounting for future SLR can have considerable impacts on the design of flood risk management strategies. PMID:28350884

Impacts of representing sea-level rise uncertainty on future flood risks: An example from San Francisco Bay.

PubMed

Ruckert, Kelsey L; Oddo, Perry C; Keller, Klaus

2017-01-01

Rising sea levels increase the probability of future coastal flooding. Many decision-makers use risk analyses to inform the design of sea-level rise (SLR) adaptation strategies. These analyses are often silent on potentially relevant uncertainties. For example, some previous risk analyses use the expected, best, or large quantile (i.e., 90%) estimate of future SLR. Here, we use a case study to quantify and illustrate how neglecting SLR uncertainties can bias risk projections. Specifically, we focus on the future 100-yr (1% annual exceedance probability) coastal flood height (storm surge including SLR) in the year 2100 in the San Francisco Bay area. We find that accounting for uncertainty in future SLR increases the return level (the height associated with a probability of occurrence) by half a meter from roughly 2.2 to 2.7 m, compared to using the mean sea-level projection. Accounting for this uncertainty also changes the shape of the relationship between the return period (the inverse probability that an event of interest will occur) and the return level. For instance, incorporating uncertainties shortens the return period associated with the 2.2 m return level from a 100-yr to roughly a 7-yr return period (∼15% probability). Additionally, accounting for this uncertainty doubles the area at risk of flooding (the area to be flooded under a certain height; e.g., the 100-yr flood height) in San Francisco. These results indicate that the method of accounting for future SLR can have considerable impacts on the design of flood risk management strategies.

78 FR 36753 - North Atlantic Coast Comprehensive Study

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-19

... landscape system, considering future sea-level rise and climate change scenarios. In addition, the... management and climate change and sea-level rise considerations. Additional information and a study area map...

A modeling study of coastal inundation induced by storm surge, sea-level rise, and subsidence in the Gulf of Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Zhaoqing; Wang, Taiping; Leung, Lai-Yung R.

The northern coasts of the Gulf of Mexico are highly vulnerable to the direct threats of climate change, such as hurricane-induced storm surge, and such risks can be potentially exacerbated by land subsidence and global sea level rise. This paper presents an application of a coastal storm surge model to study the coastal inundation process induced by tide and storm surge, and its response to the effects of land subsidence and sea level rise in the northern Gulf coast. An unstructured-grid Finite Volume Coastal Ocean Model was used to simulate tides and hurricane-induced storm surges in the Gulf of Mexico.more » Simulated distributions of co-amplitude and co-phase of semi-diurnal and diurnal tides are in good agreement with previous modeling studies. The storm surges induced by four historical hurricanes (Rita, Katrina, Ivan and Dolly) were simulated and compared to observed water levels at National Oceanic and Atmospheric Administration tide stations. Effects of coastal subsidence and future global sea level rise on coastal inundation in the Louisiana coast were evaluated using a parameter “change of inundation depth” through sensitivity simulations that were based on a projected future subsidence scenario and 1-m global sea level rise by the end of the century. Model results suggested that hurricane-induced storm surge height and coastal inundation could be exacerbated by future global sea level rise and subsidence, and that responses of storm surge and coastal inundation to the effects of sea level rise and subsidence are highly nonlinear and vary on temporal and spatial scales.« less

Relative sea level trend and variability in the central Mediterranean in the time span 1872-2014 from tide gauge data: implications for future projections

NASA Astrophysics Data System (ADS)

Anzidei, Marco; Vecchio, Antonio

2015-04-01

We used tidal data collected in the time span 1872-2014 from a set of historical and modern stations located in the central Mediterranean, along the coasts of Italy, France, Slovenia and Croatia. The longest records span across the last two or three centuries for the tidal stations of Genova, Marseille, Trieste and Venice. While data from Bakar, Dubrovink, Rovinji and Split, all located along the coast of the Adriatic sea, provide valid records for a time span about 50 years long. In addition to these stations, since 1998 become available for the Italian region new sea level data from the dense national tidal network (www.mareografico.it). These digital stations are collecting data continuously at 10 minute sampling interval with a nominal accuracy at 1 mm. Therefore, in addition to the historical stations, we have the opportunity to analyze a sea level data set that cover about the last 16 years. In this study we show and discuss the results of our analysis of sea level data for the central Mediterranean, providing new insights on sea level trend and variability for about the past 140 years. Finally, based on sea level data and IPCC reports, we provide future sea level projections for this region for the year 2100 with implications for coastal flooding of lowland areas.

Sensitivity of Hurricane Storm Surge to Land Cover and Topography Under Various Sea Level Rise Scenarios Along the Mississippi Coast

NASA Astrophysics Data System (ADS)

Bilskie, M. V.; Hagen, S. C.; Medeiros, S. C.

2013-12-01

Major Gulf hurricanes have a high probability of impacting the northern Gulf of Mexico, especially coastal Mississippi (Resio, 2007). Due to the wide and flat continental shelf, this area provides near-perfect geometry for high water levels under tropical cyclone conditions. Literature suggests with 'very high confidence that global sea level will rise at least 0.2 m and no more than 2.0 m by 2011' (Donoghue, 2011; Parris et al., 2012). Further, it is recognized that the Mississippi barrier islands are highly susceptible to a westward migration and retreating shoreline. With predictions for less frequent, more intense tropical storms, rising sea levels, and a changing landscape, it is important to understand how these changes may affect inundation extent and flooding due to hurricane storm surge. A state-of-the-art SWAN+ADCIRC hydrodynamic model of coastal Mississippi was utilized to simulate Hurricane Katrina with present day sea level conditions. Using present day as a base scenario, past (1960) and future (2050) sea level changes were simulated. In addition to altering the initial sea state, land use land cover (LULC) was modified for 1960 and 2050 based on historic data and future projections. LULC datasets are used to derive surface roughness characteristics, such as Manning's n, and wind reduction factors. The topography along the barrier islands and near the Pascagoula River, MS was also altered to reflect the 1960 landscape. Storm surge sensitivity to topographic change were addressed by comparing model results between two 1960 storm surge simulations; one with current topography and a second with changes to the barrier islands. In addition, model responses to changes in LULC are compared. The results will be used to gain insight into adapting present day storm surge models for future conditions. References Donoghue, J. (2011). Sea level history of the northern Gulf of Mexico coast and sea level rise scenarios for the near future. Climatic Change, 107(1-2), 17-33. doi: 10.1007/s10584-011-0077-x Parris, A., Bromirski, P., Burkett, V., Cayan, D., Culver, M., Hall, J., . . . Weiss, J. (2012). Global Sea Level Rise Scenarios for the United States National Climate Assessment NOAA Tech Memo OAR CPO-1 (pp. 37). Resio, D. T. (2007). White paper on estimating hurricane inundation probabilities (pp. 125). Vicksburg, MS: U.S. Army Engineering Research and Development Center.

Combining Probability Distributions of Wind Waves and Sea Level Variations to Assess Return Periods of Coastal Floods

NASA Astrophysics Data System (ADS)

Leijala, U.; Bjorkqvist, J. V.; Pellikka, H.; Johansson, M. M.; Kahma, K. K.

2017-12-01

Predicting the behaviour of the joint effect of sea level and wind waves is of great significance due to the major impact of flooding events in densely populated coastal regions. As mean sea level rises, the effect of sea level variations accompanied by the waves will be even more harmful in the future. The main challenge when evaluating the effect of waves and sea level variations is that long time series of both variables rarely exist. Wave statistics are also highly location-dependent, thus requiring wave buoy measurements and/or high-resolution wave modelling. As an initial approximation of the joint effect, the variables may be treated as independent random variables, to achieve the probability distribution of their sum. We present results of a case study based on three probability distributions: 1) wave run-up constructed from individual wave buoy measurements, 2) short-term sea level variability based on tide gauge data, and 3) mean sea level projections based on up-to-date regional scenarios. The wave measurements were conducted during 2012-2014 on the coast of city of Helsinki located in the Gulf of Finland in the Baltic Sea. The short-term sea level distribution contains the last 30 years (1986-2015) of hourly data from Helsinki tide gauge, and the mean sea level projections are scenarios adjusted for the Gulf of Finland. Additionally, we present a sensitivity test based on six different theoretical wave height distributions representing different wave behaviour in relation to sea level variations. As these wave distributions are merged with one common sea level distribution, we can study how the different shapes of the wave height distribution affect the distribution of the sum, and which one of the components is dominating under different wave conditions. As an outcome of the method, we obtain a probability distribution of the maximum elevation of the continuous water mass, which enables a flexible tool for evaluating different risk levels in the current and future climate.

Multiple stressors and the potential for synergistic loss of New England salt marshes

PubMed Central

Angelini, Christine; Bertness, Mark D.

2017-01-01

Climate change and other anthropogenic stressors are converging on coastal ecosystems worldwide. Understanding how these stressors interact to affect ecosystem structure and function has immediate implications for coastal planning, however few studies quantify stressor interactions. We examined past and potential future interactions between two leading stressors on New England salt marshes: sea-level rise and marsh crab (Sesarma reticulatum) grazing driven low marsh die-off. Geospatial analyses reveal that crab-driven die-off has led to an order of magnitude more marsh loss than sea-level rise between 2005 and 2013. However, field transplant experimental results suggest that sea-level rise will facilitate crab expansion into higher elevation marsh platforms by inundating and gradually softening now-tough high marsh peat, exposing large areas to crab-driven die-off. Taking interactive effects of marsh softening and concomitant overgrazing into account, we estimate that even modest levels of sea-level rise will lead to levels of salt marsh habitat loss that are 3x greater than the additive effects of sea-level rise and crab-driven die-off would predict. These findings highlight the importance of multiple stressor studies in enhancing mechanistic understanding of ecosystem vulnerabilities to future stress scenarios and encourage managers to focus on ameliorating local stressors to break detrimental synergisms, reduce future ecosystem loss, and enhance ecosystem resilience to global change. PMID:28859097

Multiple stressors and the potential for synergistic loss of New England salt marshes.

PubMed

Crotty, Sinead M; Angelini, Christine; Bertness, Mark D

2017-01-01

Climate change and other anthropogenic stressors are converging on coastal ecosystems worldwide. Understanding how these stressors interact to affect ecosystem structure and function has immediate implications for coastal planning, however few studies quantify stressor interactions. We examined past and potential future interactions between two leading stressors on New England salt marshes: sea-level rise and marsh crab (Sesarma reticulatum) grazing driven low marsh die-off. Geospatial analyses reveal that crab-driven die-off has led to an order of magnitude more marsh loss than sea-level rise between 2005 and 2013. However, field transplant experimental results suggest that sea-level rise will facilitate crab expansion into higher elevation marsh platforms by inundating and gradually softening now-tough high marsh peat, exposing large areas to crab-driven die-off. Taking interactive effects of marsh softening and concomitant overgrazing into account, we estimate that even modest levels of sea-level rise will lead to levels of salt marsh habitat loss that are 3x greater than the additive effects of sea-level rise and crab-driven die-off would predict. These findings highlight the importance of multiple stressor studies in enhancing mechanistic understanding of ecosystem vulnerabilities to future stress scenarios and encourage managers to focus on ameliorating local stressors to break detrimental synergisms, reduce future ecosystem loss, and enhance ecosystem resilience to global change.

Modeling Anthropogenic Impact on Sediment Balance and Relative Sea-Level Rise in Contemporary and Future Deltas

NASA Astrophysics Data System (ADS)

Tessler, Z. D.; Vorosmarty, C. J.; Overeem, I.; Syvitski, J. P.

2017-12-01

Modern deltas are dependent on human-mediated freshwater and sediment fluxes. Changes to these fluxes impact delta biogeophysical functioning, and affect the long-term sustainability of these landscapes for both human and natural systems. Here we present contemporary estimates of long-term mean sediment balance and relative sea-level rise across 46 global deltas. We model ongoing development and scenarios of future water resource management and hydropower infrastructure in upstream river basins to explore how changing sediment fluxes impact relative sea-level in coastal delta systems. Model results show that contemporary sediment fluxes, anthropogenic drivers of land subsidence, and sea-level rise result in relative sea-level rise rates in deltas that average 6.8 mm/year. Currently planned or under-construction dams can be expected to increase rates of relative sea-level rise on the order of 1 mm/year. Some deltas systems, including the Magdalena, Orinoco, and Indus, are highly sensitive to future impoundment of river basins, with RSLR rates increasing up to 4 mm/year in a high-hydropower-utilization scenario. Sediment fluxes may be reduced by up to 60% in the Danube and 21% in the Ganges-Brahmaputra-Megnha if all currently planned dams are constructed. Reduced sediment retention on deltas due to increased river channelization and local flood controls increases RSLR on average by nearly 2 mm/year. Long-term delta sustainability requires a more complete understanding of how geophysical and anthropogenic change impact delta geomorphology. Strategies for sustainable delta management that focus on local and regional drivers of change, especially groundwater and hydrocarbon extraction and upstream dam construction, can be highly impactful even in the context of global climate-induced sea-level rise.

The impact of half-a-degree Celsius upon the spatial pattern of future sea-level change.

NASA Astrophysics Data System (ADS)

Jackson, Luke

2017-04-01

It has been shown that the global thermal expansion of sea level and ocean dynamics are linearly related to global temperature change. On this basis one can estimate the difference in local sea-level change between a 1.5°C and 2.0°C world. The mitigation scenario RCP 2.6 shows an end-of-century global temperature range of 0.9 to 2.3°C (median 1.6°C). Additional sea-level components, such as mass changes in ice sheets, glaciers and land-water storage have unique spatial patterns that contribute to sea-level change and will be indirectly affected by global temperature change. We project local sea-level change for RCP 2.6 using sub-sets of models in the CMIP5 archive that follow different global temperature pathways. The method used to calculate local sea-level change is probabilistic and combines the normalised spatial patterns of sea-level components with global average projections of individual sea-level components.

Dynamics of sea level rise and coastal flooding on a changing landscape

NASA Astrophysics Data System (ADS)

Bilskie, M. V.; Hagen, S. C.; Medeiros, S. C.; Passeri, D. L.

2014-02-01

Standard approaches to determining the impacts of sea level rise (SLR) on storm surge flooding employ numerical models reflecting present conditions with modified sea states for a given SLR scenario. In this study, we advance this paradigm by adjusting the model framework so that it reflects not only a change in sea state but also variations to the landscape (morphologic changes and urbanization of coastal cities). We utilize a numerical model of the Mississippi and Alabama coast to simulate the response of hurricane storm surge to changes in sea level, land use/land cover, and land surface elevation for past (1960), present (2005), and future (2050) conditions. The results show that the storm surge response to SLR is dynamic and sensitive to changes in the landscape. We introduce a new modeling framework that includes modification of the landscape when producing storm surge models for future conditions.

Coastal Louisiana in Crisis: Subsidence or Sea Level Rise?

NASA Astrophysics Data System (ADS)

González, Juan L.; Törnqvist, Torbjörn E.

2006-11-01

The drowning of wetlands and barrier islands in coastal Louisiana has become a widely publicized environmental catastrophe in the wake of hurricanes Katrina and Rita in 2005. The devastation caused by these storms has reenergized the debate about restoring the natural coastal-defense system and building higher and sturdier levees, in anticipation of future storms. Understanding the contributions of land subsidence and eustatic (global) sea level rise to Louisiana's wetland loss is crucial to the success of any plan designed to protect coastal communities. It is argued here that accelerated sea level rise in the future may pose a larger threat than subsidence for considerable portions of coastal Louisiana.

Do we have to take an acceleration of sea level rise into account?

NASA Astrophysics Data System (ADS)

Dillingh, D.; Baart, F.; de Ronde, J.

2012-04-01

In view of preservation of safety against inundation and of the many values and functions of the coastal zone, coastal retreat is no longer acceptable. That is why it was decided to maintain the Dutch coastline on its position in 1990. Later the preservation concept was extended to the Dutch coastal foundation, which is the area that encompasses all dune area's and hard sea defences and reaches seawards until the 20m depth contour line. Present Dutch coastal policy is to grow with sea level by means of sand nourishments. A main issue for the planning of sand nourishments is the rate of sea level rise, because that is the main parameter for the volume of the sand needed. The question is than relevant if we already have to take into account an acceleration of sea level rise. Six stations with long water level records, well spread along the Dutch coast, were analysed. Correction of the measured data was considered necessary for an adaptation of the NAP in 2005 as a consequence of movements of the top of the pleistoceen, on which the NAP bench marks have been founded, and for the 18.6 year (nodal) cycle in the time series of yearly mean sea levels. It has been concluded that along the Dutch coast no significant acceleration of sea level rise could be detected yet. Over the last 120 years sea level rose with an average speed of 19 cm per century relative to NAP (the Dutch ordnance datum). Time series shorter than about 50 years showed less robust estimates of sea level rise. Future sea level rise also needs consideration in view of the estimate of future sand nourishment volumes. Scenario's for sea level rise have been derived for the years 2050 and 2100 relative to 1990 by the KNMI (Dutch Met Office) in 2006 for the Dutch situation. Plausible curves have been drawn from 1990 tangent to the linear regression line in 1990 and forced through the high and low scenario projections for 2050 and 2100. These curves show discrepancies with measurements of the last decade, particularly for the high scenario. Dutch design levels for coastal water defence structures (dikes and dunes) are based on extreme value statistics of long time series of high water levels. These design levels have typically return periods of 2000, 4000 and 10.000 years, depending on the importance of the protected dike ring. The last statistical analysis for the update of the design levels refers to the sea level situation of 1985. According to the Water Act Dutch design levels must be tested periodically (every 6 years). Due to sea level rise and tidal changes the design levels are corrected for the rise of the mean high waters from 1985 until the end of the testing period under consideration. This demands a tailoring approach for different regions or locations instead of a national average as for coastal preservation. Runs with climate models and coupled hydrodynamic models in the framework of the Essence project and the Delta Committee 2008 showed no indication for a change in the statistics of extreme storm surge levels. For the estimation of sea level rise over the last 120 years a linear regression gives the most robust estimate. Showing decadal variability needs more sophisticated models. For the last update of the design levels the elegant Whittaker smoother has been applied. Dutch policy prescribes to account for a future sea level rise of 60 cm per century for the design of new dikes or dike reinforcements and 85 cm per century for the long term (200 years) allocation of space for future reinforcements, in agreement with the KNMI'06 scenario's for sea level rise (central value and upper limit).

Managing for No Net Loss of Ecological Services: An Approach for Quantifying Loss of Coastal Wetlands due to Sea Level Rise

NASA Astrophysics Data System (ADS)

Kassakian, Jennifer; Jones, Ann; Martinich, Jeremy; Hudgens, Daniel

2017-05-01

Sea level rise has the potential to substantially alter the extent and nature of coastal wetlands and the critical ecological services they provide. In making choices about how to respond to rising sea level, planners are challenged with weighing easily quantified risks (e.g., loss of property value due to inundation) against those that are more difficult to quantify (e.g., loss of primary production or carbon sequestration services provided by wetlands due to inundation). Our goal was to develop a cost-effective, appropriately-scaled, model-based approach that allows planners to predict, under various sea level rise and response scenarios, the economic cost of wetland loss—with the estimates proxied by the costs of future restoration required to maintain the existing level of wetland habitat services. Our approach applies the Sea Level Affecting Marshes Model to predict changes in wetland habitats over the next century, and then applies Habitat Equivalency Analysis to predict the cost of restoration projects required to maintain ecological services at their present, pre-sea level rise level. We demonstrate the application of this approach in the Delaware Bay estuary and in the Indian River Lagoon (Florida), and discuss how this approach can support future coastal decision-making.

Managing for No Net Loss of Ecological Services: An Approach for Quantifying Loss of Coastal Wetlands due to Sea Level Rise.

PubMed

Kassakian, Jennifer; Jones, Ann; Martinich, Jeremy; Hudgens, Daniel

2017-05-01

Sea level rise has the potential to substantially alter the extent and nature of coastal wetlands and the critical ecological services they provide. In making choices about how to respond to rising sea level, planners are challenged with weighing easily quantified risks (e.g., loss of property value due to inundation) against those that are more difficult to quantify (e.g., loss of primary production or carbon sequestration services provided by wetlands due to inundation). Our goal was to develop a cost-effective, appropriately-scaled, model-based approach that allows planners to predict, under various sea level rise and response scenarios, the economic cost of wetland loss-with the estimates proxied by the costs of future restoration required to maintain the existing level of wetland habitat services. Our approach applies the Sea Level Affecting Marshes Model to predict changes in wetland habitats over the next century, and then applies Habitat Equivalency Analysis to predict the cost of restoration projects required to maintain ecological services at their present, pre-sea level rise level. We demonstrate the application of this approach in the Delaware Bay estuary and in the Indian River Lagoon (Florida), and discuss how this approach can support future coastal decision-making.

Global sea level linked to global temperature

PubMed Central

Vermeer, Martin; Rahmstorf, Stefan

2009-01-01

We propose a simple relationship linking global sea-level variations on time scales of decades to centuries to global mean temperature. This relationship is tested on synthetic data from a global climate model for the past millennium and the next century. When applied to observed data of sea level and temperature for 1880–2000, and taking into account known anthropogenic hydrologic contributions to sea level, the correlation is >0.99, explaining 98% of the variance. For future global temperature scenarios of the Intergovernmental Panel on Climate Change's Fourth Assessment Report, the relationship projects a sea-level rise ranging from 75 to 190 cm for the period 1990–2100. PMID:19995972

Current state and future perspectives on coupled ice-sheet - sea-level modelling

NASA Astrophysics Data System (ADS)

de Boer, Bas; Stocchi, Paolo; Whitehouse, Pippa L.; van de Wal, Roderik S. W.

2017-08-01

The interaction between ice-sheet growth and retreat and sea-level change has been an established field of research for many years. However, recent advances in numerical modelling have shed new light on the precise interaction of marine ice sheets with the change in near-field sea level, and the related stability of the grounding line position. Studies using fully coupled ice-sheet - sea-level models have shown that accounting for gravitationally self-consistent sea-level change will act to slow down the retreat and advance of marine ice-sheet grounding lines. Moreover, by simultaneously solving the 'sea-level equation' and modelling ice-sheet flow, coupled models provide a global field of relative sea-level change that is consistent with dynamic changes in ice-sheet extent. In this paper we present an overview of recent advances, possible caveats, methodologies and challenges involved in coupled ice-sheet - sea-level modelling. We conclude by presenting a first-order comparison between a suite of relative sea-level data and output from a coupled ice-sheet - sea-level model.

Marshes to mudflats—Effects of sea-level rise on tidal marshes along a latitudinal gradient in the Pacific Northwest

USGS Publications Warehouse

Thorne, Karen M.; Dugger, Bruce D.; Buffington, Kevin J.; Freeman, Chase M.; Janousek, Christopher N.; Powelson, Katherine W.; Gutenspergen, Glenn R.; Takekawa, John Y.

2015-11-17

In the Pacific Northwest, coastal wetlands support a wealth of ecosystem services including habitat provision for wildlife and fisheries and flood protection. The tidal marshes, mudflats, and shallow bays of coastal estuaries link marine, freshwater, and terrestrial habitats, and provide economic and recreational benefits to local communities. Climate change effects such as sea-level rise are altering these habitats, but we know little about how these areas will change over the next 50–100 years. Our study examined the effects of sea-level rise on nine tidal marshes in Washington and Oregon between 2012 and 2015, with the goal of providing scientific data to support future coastal planning and conservation. We compiled physical and biological data, including coastal topography, tidal inundation, vegetation structure, as well as recent and historical sediment accretion rates, to assess and model how sea-level rise may alter these ecosystems in the future. Multiple factors, including initial elevation, marsh productivity, sediment availability, and rates of sea-level rise, affected marsh persistence. Under a low sea-level rise scenario, all marshes remained vegetated with little change in the present configuration of communities of marsh plants or gradually increased proportions of middle-, high-, or transition-elevation zones of marsh vegetation. However, at most sites, mid sea-level rise projections led to loss of habitat of middle and high marshes and a gain of low marshes. Under a high sea-level rise scenario, marshes at most sites eventually converted to intertidal mudflats. Two sites (Grays Harbor and Willapa) seemed to have the most resilience to a high rate of rise in sea-level, persisting as low marsh until at least 2110. Our main model finding is that most tidal marsh study sites are resilient to sea-level rise over the next 50–70 years, but that sea-level rise will eventually outpace marsh accretion and drown most habitats of high and middle marshes by 2110.

Assessing coastal flood risk and sea level rise impacts at New York City area airports

NASA Astrophysics Data System (ADS)

Ohman, K. A.; Kimball, N.; Osler, M.; Eberbach, S.

2014-12-01

Flood risk and sea level rise impacts were assessed for the Port Authority of New York and New Jersey (PANYNJ) at four airports in the New York City area. These airports included John F. Kennedy International, LaGuardia, Newark International, and Teterboro Airports. Quantifying both present day and future flood risk due to climate change and developing flood mitigation alternatives is crucial for the continued operation of these airports. During Hurricane Sandy in October 2012 all four airports were forced to shut down, in part due to coastal flooding. Future climate change and sea level rise effects may result in more frequent shutdowns and disruptions in travel to and from these busy airports. The study examined the effects of the 1%-annual-chance coastal flooding event for present day existing conditions and six different sea level rise scenarios at each airport. Storm surge model outputs from the Federal Emergency Management Agency (FEMA) provided the present day storm surge conditions. 50th and 90thpercentile sea level rise projections from the New York Panel on Climate Change (NPCC) 2013 report were incorporated into storm surge results using linear superposition methods. These projections were evaluated for future years 2025, 2035, and 2055. In addition to the linear superposition approach for storm surge at airports where waves are a potential hazard, one dimensional wave modeling was performed to get the total water level results. Flood hazard and flood depth maps were created based on these results. In addition to assessing overall flooding at each airport, major at-risk infrastructure critical to the continued operation of the airport was identified and a detailed flood vulnerability assessment was performed. This assessment quantified flood impacts in terms of potential critical infrastructure inundation and developed mitigation alternatives to adapt to coastal flooding and future sea level changes. Results from this project are advancing the PANYNJ's understanding of the effects of sea level rise on coastal flooding at the airports and guiding decision-making in the selection of effective adaptation actions. Given the importance of these airports to transportation, this project is advancing security and continuity of national and international commerce well into the 21st century.

Sea-Level Rise and Flood Potential along the California Coast

NASA Astrophysics Data System (ADS)

Delepine, Q.; Leung, C.

2013-12-01

Sea-level rise is becoming an ever-increasing problem in California. Sea-level is expected to rise significantly in the next 100 years, which will raise flood elevations in coastal communities. This will be an issue for private homeowners, businesses, and the state. One study suggests that Venice Beach could lose a total of at least $440 million in tourism spending and tax dollars from flooding and beach erosion if sea level rises 1.4 m by 2100. In addition, several airports, such as San Francisco International Airport, are located in coastal regions that have flooded in the past and will likely be flooded again in the next 30 years, but sea-level rise is expected to worsen the effects of flooding in the coming decades It is vital for coastal communities to understand the risks associated with sea-level rise so that they can plan to adapt to it. By obtaining accurate LiDAR elevation data from the NOAA Digital Coast Website (http://csc.noaa.gov/dataviewer/?keyword=lidar#), we can create flood maps to simulate sea level rise and flooding. The data are uploaded to ArcGIS and contour lines are added for different elevations that represent future coastlines during 100-year flooding. The following variables are used to create the maps: 1. High-resolution land surface elevation data - obtained from NOAA 2. Local mean high water level - from USGS 3. Local 100-year flood water level - from the Pacific Institute 4. Sea-level rise projections for different future dates (2030, 2050, and 2100) - from the National Research Council The values from the last three categories are added to represent sea-level rise plus 100-year flooding. These values are used to make the contour lines that represent the projected flood elevations, which are then exported as KML files, which can be opened in Google Earth. Once these KML files are made available to the public, coastal communities will gain an improved understanding of how flooding and sea-level rise might affect them in the future. This would allow them to plan ahead to reduce the level of risk to homes, industry, and infrastructure San Francisco International Airport will be most likely be flooded in the next 30 years. Blue lines indicate current Mean High Water Levels. Yellow lines indicate the Mean High Water level combined with flood levels for 2030. Green, 2050, and Red lines, 2100

Characterizing uncertain sea-level rise projections to support investment decisions.

PubMed

Sriver, Ryan L; Lempert, Robert J; Wikman-Svahn, Per; Keller, Klaus

2018-01-01

Many institutions worldwide are considering how to include uncertainty about future changes in sea-levels and storm surges into their investment decisions regarding large capital infrastructures. Here we examine how to characterize deeply uncertain climate change projections to support such decisions using Robust Decision Making analysis. We address questions regarding how to confront the potential for future changes in low probability but large impact flooding events due to changes in sea-levels and storm surges. Such extreme events can affect investments in infrastructure but have proved difficult to consider in such decisions because of the deep uncertainty surrounding them. This study utilizes Robust Decision Making methods to address two questions applied to investment decisions at the Port of Los Angeles: (1) Under what future conditions would a Port of Los Angeles decision to harden its facilities against extreme flood scenarios at the next upgrade pass a cost-benefit test, and (2) Do sea-level rise projections and other information suggest such conditions are sufficiently likely to justify such an investment? We also compare and contrast the Robust Decision Making methods with a full probabilistic analysis. These two analysis frameworks result in similar investment recommendations for different idealized future sea-level projections, but provide different information to decision makers and envision different types of engagement with stakeholders. In particular, the full probabilistic analysis begins by aggregating the best scientific information into a single set of joint probability distributions, while the Robust Decision Making analysis identifies scenarios where a decision to invest in near-term response to extreme sea-level rise passes a cost-benefit test, and then assembles scientific information of differing levels of confidence to help decision makers judge whether or not these scenarios are sufficiently likely to justify making such investments. Results highlight the highly-localized and context dependent nature of applying Robust Decision Making methods to inform investment decisions.

Characterizing uncertain sea-level rise projections to support investment decisions

PubMed Central

Lempert, Robert J.; Wikman-Svahn, Per; Keller, Klaus

2018-01-01

Many institutions worldwide are considering how to include uncertainty about future changes in sea-levels and storm surges into their investment decisions regarding large capital infrastructures. Here we examine how to characterize deeply uncertain climate change projections to support such decisions using Robust Decision Making analysis. We address questions regarding how to confront the potential for future changes in low probability but large impact flooding events due to changes in sea-levels and storm surges. Such extreme events can affect investments in infrastructure but have proved difficult to consider in such decisions because of the deep uncertainty surrounding them. This study utilizes Robust Decision Making methods to address two questions applied to investment decisions at the Port of Los Angeles: (1) Under what future conditions would a Port of Los Angeles decision to harden its facilities against extreme flood scenarios at the next upgrade pass a cost-benefit test, and (2) Do sea-level rise projections and other information suggest such conditions are sufficiently likely to justify such an investment? We also compare and contrast the Robust Decision Making methods with a full probabilistic analysis. These two analysis frameworks result in similar investment recommendations for different idealized future sea-level projections, but provide different information to decision makers and envision different types of engagement with stakeholders. In particular, the full probabilistic analysis begins by aggregating the best scientific information into a single set of joint probability distributions, while the Robust Decision Making analysis identifies scenarios where a decision to invest in near-term response to extreme sea-level rise passes a cost-benefit test, and then assembles scientific information of differing levels of confidence to help decision makers judge whether or not these scenarios are sufficiently likely to justify making such investments. Results highlight the highly-localized and context dependent nature of applying Robust Decision Making methods to inform investment decisions. PMID:29414978

Overestimation of marsh vulnerability to sea level rise

USGS Publications Warehouse

Kirwan, Matthew L.; Temmerman, Stijn; Skeehan, Emily E.; Guntenspergen, Glenn R.; Fagherazzi, Sergio

2016-01-01

Coastal marshes are considered to be among the most valuable and vulnerable ecosystems on Earth, where the imminent loss of ecosystem services is a feared consequence of sea level rise. However, we show with a meta-analysis that global measurements of marsh elevation change indicate that marshes are generally building at rates similar to or exceeding historical sea level rise, and that process-based models predict survival under a wide range of future sea level scenarios. We argue that marsh vulnerability tends to be overstated because assessment methods often fail to consider biophysical feedback processes known to accelerate soil building with sea level rise, and the potential for marshes to migrate inland.

The importance of vegetation change in the prediction of future tropical cyclone flood statistics

NASA Astrophysics Data System (ADS)

Irish, J. L.; Resio, D.; Bilskie, M. V.; Hagen, S. C.; Weiss, R.

2015-12-01

Global sea level rise is a near certainty over the next century (e.g., Stocker et al. 2013 [IPCC] and references therein). With sea level rise, coastal topography and land cover (hereafter "landscape") is expected to change and tropical cyclone flood hazard is expected to accelerate (e.g., Irish et al. 2010 [Ocean Eng], Woodruff et al. 2013 [Nature], Bilskie et al. 2014 [Geophys Res Lett], Ferreira et al. 2014 [Coast Eng], Passeri et al. 2015 [Nat Hazards]). Yet, the relative importance of sea-level rise induced landscape change on future tropical cyclone flood hazard assessment is not known. In this paper, idealized scenarios are used to evaluate the relative impact of one class of landscape change on future tropical cyclone extreme-value statistics in back-barrier regions: sea level rise induced vegetation migration and loss. The joint probability method with optimal sampling (JPM-OS) (Resio et al. 2009 [Nat Hazards]) with idealized surge response functions (e.g., Irish et al. 2009 [Nat Hazards]) is used to quantify the present-day and future flood hazard under various sea level rise scenarios. Results are evaluated in terms of their impact on the flood statistics (a) when projected flood elevations are included directly in the JPM analysis (Figure 1) and (b) when represented as additional uncertainty within the JPM integral (Resio et al. 2013 [Nat Hazards]), i.e., as random error. Findings are expected to aid in determining the level of effort required to reasonably account for future landscape change in hazard assessments, namely in determining when such processes are sufficiently captured by added uncertainty and when sea level rise induced vegetation changes must be considered dynamically, via detailed modeling initiatives. Acknowledgements: This material is based upon work supported by the National Science Foundation under Grant No. CMMI-1206271 and by the National Sea Grant College Program of the U.S. Department of Commerce's National Oceanic and Atmospheric Administration under Grant No. NA10OAR4170099. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of these organizations. The STOKES ARCC at the University of Central Florida provided computational resources for storm surge simulations.

A model of water and sediment balance as determinants of relative sea level rise in contemporary and future deltas

NASA Astrophysics Data System (ADS)

Tessler, Zachary D.; Vörösmarty, Charles J.; Overeem, Irina; Syvitski, James P. M.

2018-03-01

Modern deltas are dependent on human-mediated freshwater and sediment fluxes. Changes to these fluxes impact delta biogeophysical functioning and affect the long-term sustainability of these landscapes for human and for natural systems. Here we present contemporary estimates of long-term mean sediment balance and relative sea level rise across 46 global deltas. We model scenarios of contemporary and future water resource management schemes and hydropower infrastructure in upstream river basins to explore how changing sediment fluxes impact relative sea level rise in delta systems. Model results show that contemporary sediment fluxes, anthropogenic drivers of land subsidence, and sea level rise result in delta relative sea level rise rates that average 6.8 mm/y. Assessment of impacts of planned and under-construction dams on relative sea level rise rates suggests increases on the order of 1 mm/y in deltas with new upstream construction. Sediment fluxes are estimated to decrease by up to 60% in the Danube and 21% in the Ganges-Brahmaputra-Meghna if all currently planned dams are constructed. Reduced sediment retention on deltas caused by increased river channelization and management has a larger impact, increasing relative sea level rise on average by nearly 2 mm/y. Long-term delta sustainability requires a more complete understanding of how geophysical and anthropogenic change impact delta geomorphology. Local and regional strategies for sustainable delta management that focus on local and regional drivers of change, especially groundwater and hydrocarbon extraction and upstream dam construction, can be highly impactful even in the context of global climate-induced sea level rise.

Army Corps of Engineers: Efforts to Assess the Impact of Extreme Weather Events

DTIC Science & Technology

2015-07-01

evaluate the effects of projected future sea level change on its projects and what to consider when adapting projects to this projected change. In...vulnerability assessments for sea level rise on its coastal projects and has begun conducting such assessments at inland watersheds. U.S. Army Corps of...Army Corps of Engineers’ Hurricane Barrier Design Elevation Changes Due to Sea Level Rise 30 Contents

A framework for sea level rise vulnerability assessment for southwest U.S. military installations

USGS Publications Warehouse

Chadwick, B.; Flick, Reinhard; Helly, J.; Nishikawa, Tracy; Pei, Fang Wang; O'Reilly, W.; Guza, R.; Bromirski, Peter; Young, A.; Crampton, W.; Wild, B.; Canner, I.

2011-01-01

We describe an analysis framework to determine military installation vulnerabilities under increases in local mean sea level as projected over the next century. The effort is in response to an increasing recognition of potential climate change ramifications for national security and recommendations that DoD conduct assessments of the impact on U.S. military installations of climate change. Results of the effort described here focus on development of a conceptual framework for sea level rise vulnerability assessment at coastal military installations in the southwest U.S. We introduce the vulnerability assessment in the context of a risk assessment paradigm that incorporates sources in the form of future sea level conditions, pathways of impact including inundation, flooding, erosion and intrusion, and a range of military installation specific receptors such as critical infrastructure and training areas. A unique aspect of the methodology is the capability to develop wave climate projections from GCM outputs and transform these to future wave conditions at specific coastal sites. Future sea level scenarios are considered in the context of installation sensitivity curves which reveal response thresholds specific to each installation, pathway and receptor. In the end, our goal is to provide a military-relevant framework for assessment of accelerated SLR vulnerability, and develop the best scientifically-based scenarios of waves, tides and storms and their implications for DoD installations in the southwestern U.S.

Impacts of climate-change-driven sea level rise on intertidal rocky reef habitats will be variable and site specific.

PubMed

Thorner, Jaqueline; Kumar, Lalit; Smith, Stephen D A

2014-01-01

Intertidal rocky reefs are complex and rich ecosystems that are vulnerable to even the smallest fluctuations in sea level. We modelled habitat loss associated with sea level rise for intertidal rocky reefs using GIS, high-resolution digital imagery, and LIDAR technology at fine-scale resolution (0.1 m per pixel). We used projected sea levels of +0.3 m, +0.5 m and +1.0 m above current Mean Low Tide Level (0.4 m). Habitat loss and changes were analysed for each scenario for five headlands in the Solitary Islands Marine Park (SIMP), Australia. The results indicate that changes to habitat extent will be variable across different shores and will not necessarily result in net loss of area for some habitats. In addition, habitat modification will not follow a regular pattern over the projected sea levels. Two of the headlands included in the study currently have the maximum level of protection within the SIMP. However, these headlands are likely to lose much of the habitat known to support biodiverse assemblages and may not continue to be suitable sanctuaries into the future. The fine-scale approach taken in this study thus provides a protocol not only for modelling habitat modification but also for future proofing conservation measures under a scenario of changing sea levels.

Mental health issues from rising sea level in a remote coastal region of the Solomon Islands: current and future.

PubMed

Asugeni, James; MacLaren, David; Massey, Peter D; Speare, Rick

2015-12-01

There is little published research about mental health and climate change in the Pacific, including Solomon Islands. Solomon Islands has one of the highest rates of sea-level rise globally. The aim of this research was to document mental health issues related to sea-level rise for people in East Malaita, Solomon Islands. A cross-sectional study was carried out in six low-lying villages in East Malaita, Solomon Islands. The researcher travelled to villages by dugout canoe. In addition to quantitative, closed-ended questions, open-ended questions with villagers explored individual and community responses to rising sea level. Of 60 people asked, 57 completed the questionnaire. Of these, 90% reported having seen a change in the weather patterns. Nearly all participants reported that sea-level rise is affecting them and their family and is causing fear and worry on a personal and community level. Four themes emerged from the qualitative analysis: experience of physical impacts of climate change; worry about the future; adaptation to climate change; government response needed. Given predictions of ongoing sea-level rise in the Pacific it is essential that more research is conducted to further understand the human impact of climate change for small island states which will inform local, provincial and national-level mental health responses. © The Royal Australian and New Zealand College of Psychiatrists 2015.

Predicting location-specific extreme coastal floods in the future climate by introducing a probabilistic method to calculate maximum elevation of the continuous water mass caused by a combination of water level variations and wind waves

NASA Astrophysics Data System (ADS)

Leijala, Ulpu; Björkqvist, Jan-Victor; Johansson, Milla M.; Pellikka, Havu

2017-04-01

Future coastal management continuously strives for more location-exact and precise methods to investigate possible extreme sea level events and to face flooding hazards in the most appropriate way. Evaluating future flooding risks by understanding the behaviour of the joint effect of sea level variations and wind waves is one of the means to make more comprehensive flooding hazard analysis, and may at first seem like a straightforward task to solve. Nevertheless, challenges and limitations such as availability of time series of the sea level and wave height components, the quality of data, significant locational variability of coastal wave height, as well as assumptions to be made depending on the study location, make the task more complicated. In this study, we present a statistical method for combining location-specific probability distributions of water level variations (including local sea level observations and global mean sea level rise) and wave run-up (based on wave buoy measurements). The goal of our method is to obtain a more accurate way to account for the waves when making flooding hazard analysis on the coast compared to the approach of adding a separate fixed wave action height on top of sea level -based flood risk estimates. As a result of our new method, we gain maximum elevation heights with different return periods of the continuous water mass caused by a combination of both phenomena, "the green water". We also introduce a sensitivity analysis to evaluate the properties and functioning of our method. The sensitivity test is based on using theoretical wave distributions representing different alternatives of wave behaviour in relation to sea level variations. As these wave distributions are merged with the sea level distribution, we get information on how the different wave height conditions and shape of the wave height distribution influence the joint results. Our method presented here can be used as an advanced tool to minimize over- and underestimation of the combined effect of sea level variations and wind waves, and to help coastal infrastructure planning and support smooth and safe operation of coastal cities in a changing climate.

Sea level data and techniques for detecting vertical crustal movements

NASA Technical Reports Server (NTRS)

Lennon, G. W.

1978-01-01

An attempt is made to survey problems, requirements, and the outlook for the future in the study of sea level time series so as to determine the relative movement of land and sea levels. The basic aim is to eliminate from the record the contributions from whatever marine dynamic phenomena respond to treatment, allowing the secular element to be identified with optimum clarity. Nevertheless the concept of sea level perturbation varies according to regional experience. The recent work of the Permanent Service for Mean Sea Level helps to eliminate geodetic noise from the series and makes it possible, perhaps, to treat the global mean sea level data bank so as to define eustatic changes in ocean volume which, in the present context, may be regarded as the final goal, allowing the identification of vertical crustal motion itself.

The Blackwater NWR inundation model. Rising sea level on a low-lying coast: land use planning for wetlands

USGS Publications Warehouse

Larsen, Curt; Clark, Inga; Guntenspergen, Glenn; Cahoon, Don; Caruso, Vincent; Hupp, Cliff; Yanosky, Tom

2004-01-01

The Blackwater National Wildlife Refuge (BNWR), on the Eastern Shore of Chesapeake Bay (figure 1), occupies an area less than 1 meter above sea level. The Refuge has been featured prominently in studies of the impact of sea level rise on coastal wetlands. Most notably, the refuge has been sited by the Intergovernmental Panel on Climate Change (IPCC) as a key example of 'wetland loss' attributable to rising sea level due to global temperature increase. Comparative studies of aerial photos taken since 1938 show an expanding area of open water in the central area of the refuge. The expanding area of open water can be shown to parallel the record of sea level rise over the past 60 years. The U.S. Fish and Wildlife Service (FWS) manages the refuge to support migratory waterfowl and to preserve endangered upland species. High marsh vegetation is critical to FWS waterfowl management strategies. A broad area once occupied by high marsh has decreased with rising sea level. The FWS needs a planning tool to help predict current and future areas of high marsh available for waterfowl. 'Wetland loss' is a relative term. It is dependant on the boundaries chosen for measurement. Wetland vegetation, zoned by elevation and salinity (figure 3), respond to rising sea level. Wetlands migrate inland and upslope and may vary in areas depending on the adjacent land slopes. Refuge managers need a geospatial tool that allows them to predict future areas that will be converted to high and intertidal marsh. Shifts in location and area of coverage must be anticipated. Viability of a current marsh area is also important. When will sea level rise make short-term management strategies to maintain an area impractical? The USGS has developed an inundation model for the BNWR centered on the refuge and surrounding areas. Such models are simple in concept, but they require a detailed topographic map upon which to superimpose future sea level positions. The new system of LIDAR mapping of land and shallow water surfaces has solved this problem. Our team has developed a detailed LIDAR map of the BNWR area at a 30 centimeter (ca. 1 ft) contour interval (figure 2). The new map allows us to identify the present marsh vegetation zones and to predict the location and area of future zones on a decade-by- decade basis over the next century at increments of sea level rise on the order of 3 cm/decade (ca. 1 inch). We have developed two scenarios for the model. The first is a steady-state model that uses the historic rate of sea level rise of 3.1 mm/yr to predict marsh areas. The second is a 'global warming' scenario utilizing a conservative IPCC model with an exponentially-increasing rate of sea level rise. Under either scenario, the BNWR is progressively inundated with an expanding core of open water. Although their positions change in the future, the areas of intertidal marsh as well as those of the critical high marsh remain fairly constant until the year 2050. Beyond that time, the low-lying land surface is overtopped by rising sea level and the area is dominated by open water. Our model suggests that wetland habitat in the Blackwater area might be maintained and sustained through a combination of public and private preservation efforts through easements in combination with judicious Federal land acquisition into the predicted areas of suitable marsh formation - but for only the next 50 years. Beyond that time much of this area will become open water.

Regional Sea Level Changes Projected by the NASA/GISS Atmosphere-Ocean Model

NASA Technical Reports Server (NTRS)

Russell, Gary L.; Gornitz, Vivien; Miller, James R.

1999-01-01

Sea level has been rising for the past century, and inhabitants of the Earth's coastal regions will want to understand and predict future sea level changes. In this study we present results from new simulations of the Goddard Institute for Space Studies (GISS) global atmosphere-ocean model from 1950 to 2099. Model results are compared with observed sea level changes during the past 40 years at 17 coastal stations around the world. Using observed levels of greenhouse gases between 1950 and 1990 and a compounded 0.5% annual increase in Co2 after 1990, model projections show that global sea level measured from 1950 will rise by 61 mm in the year 2000, by 212 mm in 2050, and by 408 mm in 2089. By 2089, two thirds of the global sea level rise will be due to thermal expansion and one third will be due to ocean mass changes. The spatial distribution of sea level rise is different than that projected by rigid lid ocean models.

Effects of sea-level rise and pumpage elimination on saltwater intrusion in the Hilton Head Island area, South Carolina, 2004-2104

USGS Publications Warehouse

Payne, Dorothy F.

2010-01-01

Saltwater intrusion of the Upper Floridan aquifer has been observed in the Hilton Head area, South Carolina since the late 1970s and currently affects freshwater supply. Rising sea level in the Hilton Head Island area may contribute to the occurrence of and affect the rate of saltwater intrusion into the Upper Floridan aquifer by increasing the hydraulic gradient and by inundating an increasing area with saltwater, which may then migrate downward into geologic units that presently contain freshwater. Rising sea level may offset any beneficial results from reductions in groundwater pumpage, and thus needs to be considered in groundwater-management decisions. A variable-density groundwater flow and transport model was modified from a previously existing model to simulate the effects of sea-level rise in the Hilton Head Island area. Specifically, the model was used to (1) simulate trends of saltwater intrusion from predevelopment to the present day (1885-2004) and evaluate the conceptual model, (2) project these trends from the present day into the future based on different potential rates of sea-level change, and (3) evaluate the relative influences of pumpage and sea-level rise on saltwater intrusion. Four scenarios were simulated for 2004-2104: (1) continuation of the estimated sea-level rise rate over the last century, (2) a doubling of the sea-level rise, (3) a cessation of sea-level rise, and (4) continuation of the rate over the last century coupled with an elimination of all pumpage. Results show that, if present-day (year 2004) pumping conditions are maintained, the extent of saltwater in the Upper Floridan aquifer will increase, whether or not sea level continues to rise. Furthermore, if all pumpage is eliminated and sea level continues to rise, the simulated saltwater extent in the Upper Floridan aquifer is reduced. These results indicate that pumpage is a strong driving force for simulated saltwater intrusion, more so than sea-level rise at current rates. However, results must be considered in light of limitations in the model, including, but not limited to uncertainty in field data, the conceptual model, the physical properties and representation of the hydrogeologic framework, and boundary and initial conditions, as well as uncertainty in future conditions, such as the rate of sea-level rise.

Advanced Regional and Decadal Predictions of Coastal Inundation for the U.S. Atlantic and Gulf Coasts (Invited)

NASA Astrophysics Data System (ADS)

Horton, B.; Corbett, D. R.; Donnelly, J. P.; Kemp, A.; Lin, N.; Lindeman, K.; Mann, M. E.; Peltier, W. R.; Rahmstorf, S.

2013-12-01

Future inundation of the U.S. Atlantic and Gulf coasts will depend upon sea-level rise and the intensity and frequency of tropical cyclones, each of which will be affected by climate change. Through ongoing, collaborative research we are employing new interdisciplinary approaches to bring about a step change in the reliability of predictions of such inundation. The rate of sea level rise along the U.S. Atlantic and Gulf coasts increased throughout the 20th century. Whilst there is widespread agreement that it continue to accelerate during the 21st century, great uncertainty surrounds its magnitude and geographic variability. Key uncertainties include the role of continental ice sheets, mountain glaciers, and ocean density changes. Insufficient understanding of these complex physical processes precludes accurate prediction of sea-level rise. New approaches using semi-empirical models that relate instrumental records of climate and sea-level rise have projected up to 2 m of sea-level rise by AD 2100. But the time span of instrumental sea-level records is insufficient to adequately constrain the climate:sea-level relationship. We produced new, high-resolution proxy sea-level reconstructions to provide crucial additional constraints to such semi-empirical models. Our dataset spans the alternation between the 'Medieval Climate Anomaly' and 'Little Ice Age'. Before the models can provide appropriate data for coastal management and planning, they must be complemented with regional estimates of sea-level rise. Therefore, the proxy sea-level data has been collected from four study areas (Connecticut, New Jersey, North Carolina and Florida) to accommodate the required extent of regional variability. In the case of inundation arising from tropical cyclones, the historical and observational records are insufficient for predicting their nature and recurrence, because they are such extreme and rare events. Moreover, future storm surges will be superimposed on background sea-level rise. To overcome these problems, we coupled regional sea-level rise projections with hurricane simulations and storm surge models to map coastal inundation for the current climate and the best and worst case climate scenarios of the IPCC AR4. With agency, NGO, and business partners, we have integrated these findings into coastal policy initiatives, including the first ever adoption of sea level Adaptation Action Areas in a Florida city land use plan.

A Dynamic Flood Inundation Model Framework to Assess Coastal Flood Risk in a Changing Climate

NASA Astrophysics Data System (ADS)

Bilskie, M. V.; Hagen, S. C.; Passeri, D. L.; Alizad, K.; Medeiros, S. C.; Irish, J. L.

2015-12-01

Coastal regions around the world are susceptible to a variety of natural disasters causing extreme inundation. It is anticipated that the vulnerability of coastal cities will increase due to the effects of climate change, and in particular sea level rise (SLR). A novel framework was developed to generate a suite of physics-based storm surge models that include projections of coastal floodplain dynamics under climate change scenarios: shoreline erosion/accretion, dune morphology, salt marsh migration, and population dynamics. First, the storm surge inundation model was extensively validated for present day conditions with respect to astronomic tides and hindcasts of Hurricane Ivan (2004), Dennis (2005), Katrina (2005), and Isaac (2012). The model was then modified to characterize the future outlook of the landscape for four climate change scenarios for the year 2100 (B1, B2, A1B, and A2), and each climate change scenario was linked to a sea level rise of 0.2 m, 0.5 m, 1.2 m, and 2.0 m. The adapted model was then used to simulate hurricane storm surge conditions for each climate scenario using a variety of tropical cyclones as the forcing mechanism. The collection of results shows the intensification of inundation area and the vulnerability of the coast to potential future climate conditions. The methodology developed herein to assess coastal flooding under climate change can be performed across any coastal region worldwide, and results provide awareness of regions vulnerable to extreme flooding in the future. Note: The main theme behind this work is to appear in a future Earth's Future publication. Bilskie, M. V., S. C. Hagen, S. C. Medeiros, and D. L. Passeri (2014), Dynamics of sea level rise and coastal flooding on a changing landscape, Geophysical Research Letters, 41(3), 927-934. Parris, A., et al. (2012), Global Sea Level Rise Scenarios for the United States National Climate AssessmentRep., 37 pp. Passeri, D. L., S. C. Hagen, M. V. Bilskie, and S. C. Medeiros (2014), On the significance of incorporating shoreline changes for evaluating coastal hydrodynamics under sea level rise scenarios, Natural Hazards, 1599-1617. Passeri, D. L., S. C. Hagen, S. C. Medeiros, M. V. Bilskie, K. Alizad, and D. Wang (2015), The dynamic effects of sea level rise on low gradient coastal landscapes: a review, Earth's Future, 3.

Increasing extreme water level flood risk as a result of future sea-level rise: A case study on a coastal city in China

NASA Astrophysics Data System (ADS)

Feng, A.; Wu, S.

2016-12-01

Extreme water levels, caused by the joint occurrence of storm surges and high tides, always lead to super floods along coastlines. In the context of climate change, this study explored the impact of future sea-level rise on the flood risk of extreme water levels. Using Rongcheng City in Shandong Province, China as a case study, flooded area, expected direct damage losses, and affected population and GDP were assessed for 2050 and 2100 under three greenhouse gas concentration Representative Concentration Pathways (RCP) scenarios, 2.6, 4.5, and 8.5. Results indicate that, as a result of sea-level rise induced by climate change, the flooded areas of Rongcheng City would increase by 3.23% to 10.64% in 2050 and by as much as 4.98% to 19.87% in 2100, compared with current recurrence periods. Residential land and farmland are at greatest risk of flooding in terms of exposure and losses than other land-use types, and under a high degree RCP 8.5 scenario, expected damage losses would be between 59.84 billion and 86.45 billion in 2050. Results show that the increase in total direct damage losses would reach an average of 60% in 2100 as a result of a 0.82 m sea-level rise. Similarly, affected population and GDP would increase by between 4.95% and 13.87% and between 3.66% and 10.95% in 2050, and by as much as 7.69% to 29.01% and 5.30% to 20.50% in 2100. This study shows that sea-level rise significantly shortens recurrence periods of extreme water levels, makes extreme flood events more frequent, and exacerbates the risk of future flooding. Our results suggest that, if there is no adaptation, sea-level rise will greatly increase the risk of flooding and severely impact human habitability along coastlines.

Impact of accelerated future global mean sea level rise on hypoxia in the Baltic Sea

NASA Astrophysics Data System (ADS)

Meier, H. E. M.; Höglund, A.; Eilola, K.; Almroth-Rosell, E.

2017-07-01

Expanding hypoxia is today a major threat for many coastal seas around the world and disentangling its drivers is a large challenge for interdisciplinary research. Using a coupled physical-biogeochemical model we estimate the impact of past and accelerated future global mean sea level rise (GSLR) upon water exchange and oxygen conditions in a semi-enclosed, shallow sea. As a study site, the Baltic Sea was chosen that suffers today from eutrophication and from dead bottom zones due to (1) excessive nutrient loads from land, (2) limited water exchange with the world ocean and (3) perhaps other drivers like global warming. We show from model simulations for the period 1850-2008 that the impacts of past GSLR on the marine ecosystem were relatively small. If we assume for the end of the twenty-first century a GSLR of +0.5 m relative to today's mean sea level, the impact on the marine ecosystem may still be small. Such a GSLR corresponds approximately to the projected ensemble-mean value reported by the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. However, we conclude that GSLR should be considered in future high-end projections (>+1 m) for the Baltic Sea and other coastal seas with similar hydrographical conditions as in the Baltic because GSLR may lead to reinforced saltwater inflows causing higher salinity and increased vertical stratification compared to present-day conditions. Contrary to intuition, reinforced ventilation of the deep water does not lead to overall improved oxygen conditions but causes instead expanded dead bottom areas accompanied with increased internal phosphorus loads from the sediments and increased risk for cyanobacteria blooms.

Coastal Hazards and Integration of Impacts in Local Adaptation Planning

NASA Astrophysics Data System (ADS)

Knudsen, P.; Sorensen, C.; Molgaard, M. R.; Broge, N. H.; Andersen, O. B.

2016-12-01

Data on sea and groundwater levels, precipitation, land subsidence, geology, and geotechnical soil properties are combined with information on flood and erosion protection measures to analyze water-related impacts from climate change at an exposed coastal location. Future sea extremes will have a large impact but several coupled effects in the hydrological system need to be considered as well to provide for optimal protection and mitigation efforts. For instance, the investment and maintenance costs of securing functional water and wastewater pipes are significantly reduced by incorporating knowledge about climate change. The translation of regional sea level rise evidence and projections to concrete impact measures should take into account the potentially affected stakeholders who must collaborate on common and shared adaptation solutions. Here, knowledge integration across levels of governance and between research, private and public institutions, and the local communities provides: understanding of the immediate and potential future challenges; appreciation of different stakeholder motives, business agendas, legislative constraints etc., and a common focus on how to cost-efficiently adapt to and manage impacts of climate change. By construction of a common working platform that is updated with additional data and knowledge, e.g. from future regional models or extreme events, advances in sea level research can more readily be translated into concrete and local impact measures in a way that handles uncertainties in the future climate and urban development as well as suiting the varying stakeholder needs.

Using simulations to forecast homeowner response to sea level rise in South Florida: Will they stay or will they go?

NASA Astrophysics Data System (ADS)

Treuer, G.

2017-12-01

Sea level rise threatens coastal communities around the world, including South Florida which may be the most financially vulnerable region in the world. Proactive investments in sea level rise adaptive flood protections could reduce South Florida's financial vulnerability. However, it is unclear if local governments and homeowners will be willing to make those investments before it is too late. Our research explores this issue by reporting the results of a novel online simulation that accelerates 348 South Florida homeowners thirty-five years into the future so that they can `live' the effects of sea level rise. The results contain a mix of optimism and caution for the prospects of future adaptation. On the positive side over 75% of participants indicated a willingness to support bond issues to pay for adaptation, even as the costs of the measures and effects of sea level rise increased over the years. Likewise, we find little evidence that politically conservative residents who normally have more skeptical views about climate change would be any less inclined to support adaptation, or only look to information sources that downplay the threat. On the negative side, homeowner interest in moving out of the region increases steadily over time as the sea level rises. This is driven by an increase in worry associated with viewing more information within the simulation.

Coastal barrier stratigraphy for Holocene high-resolution sea-level reconstruction

PubMed Central

Costas, Susana; Ferreira, Óscar; Plomaritis, Theocharis A.; Leorri, Eduardo

2016-01-01

The uncertainties surrounding present and future sea-level rise have revived the debate around sea-level changes through the deglaciation and mid- to late Holocene, from which arises a need for high-quality reconstructions of regional sea level. Here, we explore the stratigraphy of a sandy barrier to identify the best sea-level indicators and provide a new sea-level reconstruction for the central Portuguese coast over the past 6.5 ka. The selected indicators represent morphological features extracted from coastal barrier stratigraphy, beach berm and dune-beach contact. These features were mapped from high-resolution ground penetrating radar images of the subsurface and transformed into sea-level indicators through comparison with modern analogs and a chronology based on optically stimulated luminescence ages. Our reconstructions document a continuous but slow sea-level rise after 6.5 ka with an accumulated change in elevation of about 2 m. In the context of SW Europe, our results show good agreement with previous studies, including the Tagus isostatic model, with minor discrepancies that demand further improvement of regional models. This work reinforces the potential of barrier indicators to accurately reconstruct high-resolution mid- to late Holocene sea-level changes through simple approaches. PMID:27929122

Separating decadal global water cycle variability from sea level rise.

PubMed

Hamlington, B D; Reager, J T; Lo, M-H; Karnauskas, K B; Leben, R R

2017-04-20

Under a warming climate, amplification of the water cycle and changes in precipitation patterns over land are expected to occur, subsequently impacting the terrestrial water balance. On global scales, such changes in terrestrial water storage (TWS) will be reflected in the water contained in the ocean and can manifest as global sea level variations. Naturally occurring climate-driven TWS variability can temporarily obscure the long-term trend in sea level rise, in addition to modulating the impacts of sea level rise through natural periodic undulation in regional and global sea level. The internal variability of the global water cycle, therefore, confounds both the detection and attribution of sea level rise. Here, we use a suite of observations to quantify and map the contribution of TWS variability to sea level variability on decadal timescales. In particular, we find that decadal sea level variability centered in the Pacific Ocean is closely tied to low frequency variability of TWS in key areas across the globe. The unambiguous identification and clean separation of this component of variability is the missing step in uncovering the anthropogenic trend in sea level and understanding the potential for low-frequency modulation of future TWS impacts including flooding and drought.

Coastal barrier stratigraphy for Holocene high-resolution sea-level reconstruction.

PubMed

Costas, Susana; Ferreira, Óscar; Plomaritis, Theocharis A; Leorri, Eduardo

2016-12-08

The uncertainties surrounding present and future sea-level rise have revived the debate around sea-level changes through the deglaciation and mid- to late Holocene, from which arises a need for high-quality reconstructions of regional sea level. Here, we explore the stratigraphy of a sandy barrier to identify the best sea-level indicators and provide a new sea-level reconstruction for the central Portuguese coast over the past 6.5 ka. The selected indicators represent morphological features extracted from coastal barrier stratigraphy, beach berm and dune-beach contact. These features were mapped from high-resolution ground penetrating radar images of the subsurface and transformed into sea-level indicators through comparison with modern analogs and a chronology based on optically stimulated luminescence ages. Our reconstructions document a continuous but slow sea-level rise after 6.5 ka with an accumulated change in elevation of about 2 m. In the context of SW Europe, our results show good agreement with previous studies, including the Tagus isostatic model, with minor discrepancies that demand further improvement of regional models. This work reinforces the potential of barrier indicators to accurately reconstruct high-resolution mid- to late Holocene sea-level changes through simple approaches.

Vulnerability of marginal seas to sea level rise

NASA Astrophysics Data System (ADS)

Gomis, Damia; Jordà, Gabriel

2017-04-01

Sea level rise (SLR) is a serious thread for coastal areas and has a potential negative impact on society and economy. SLR can lead for instance to land loss, beach reduction, increase of the damage of marine storms on coastal infrastructures and to the salinization of underground water streams. It is well acknowledged that future SLR will be inhomogeneous across the globe, with regional differences of up to 100% with respect to global mean sea level (GMSL). Several studies have addressed the projections of SLR at regional scale, but most of them are based on global climate models (GCMs) that have a relatively coarse spatial resolution (>1°). In marginal seas this has proven to be a strong limitation, as their particular configurations require spatial resolutions that are not reachable by present GCMs. A paradigmatic case is the Mediterranean Sea, connected to the global ocean through the Strait of Gibraltar, a narrow passage of 14 km width. The functioning of the Mediterranean Sea involves a variety of processes including an overturning circulation, small-scale convection and a rich mesoscale field. Moreover, the long-term evolution of Mediterranean sea level has been significantly different from the global mean during the last decades. The observations of present climate and the projections for the next decades have lead some authors to hypothesize that the particular characteristics of the basin could allow Mediterranean mean sea level to evolve differently from the global mean. Assessing this point is essential to undertake proper adaptation strategies for the largely populated Mediterranean coastal areas. In this work we apply a new approach that combines regional and global projections to analyse future SLR. In a first step we focus on the quantification of the expected departures of future Mediterranean sea level from GMSL evolution and on the contribution of different processes to these departures. As a result we find that, in spite of its particularities, Mediterranean Sea level would follow global changes with departures lower than + 5 cm. In a second step we use the same methodology to obtain SLR projections at global scale in order to assess the vulnerability of other coastal areas. Namely, we define a vulnerability index based on relating the characteristics of present day variability with SLR projections under different scenarios. Results show that the averaged vulnerability index is 0.5 for scenario RCP8.5 (projected SLR is about a half of the maximum sea level recorded in the last decades). However, in the Mediterranean, the Caribbean and the Sea of Japan the vulnerability index is much higher (2.6, 2.4 and 2.1, respectively). From this point of view, therefore, these regions could be considered the most vulnerable regions in the world.

Sea level: measuring the bounding surfaces of the ocean

PubMed Central

Tamisiea, Mark E.; Hughes, Chris W.; Williams, Simon D. P.; Bingley, Richard M.

2014-01-01

The practical need to understand sea level along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global sea level. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of sea-level rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in sea level. While information from many scientific disciplines is needed to understand sea-level change, this review focuses on contributions from geodesy and the role of the ocean's bounding surfaces: the sea surface and the Earth's crust. PMID:25157196

Inland sea as a unit for environmental history: East Asian inland seas from prehistory to future.

PubMed

Lindstrom, Kati; Uchiyama, Junzo

2012-04-01

The boundaries of landscape policies often coincide with political or economic boundaries, thus creating a situation where a unit of landscape protection or management reflects more its present political status than its historico-geographical situation, its historical function and formation. At the same time, it is evident that no unit can exist independently of the context that has given birth to it and that environmental protection in isolated units cannot be very effective. The present paper will discuss inland sea as a landscape unit from prehistory to modern days and its implications for future landscape planning, using EastAsian inland sea (Japan Sea and East China Sea) rim as an example. Historically an area of active communication, EastAsian inland sea rim has become a politically very sharply divided area. The authors will bring examples to demonstrate how cultural communication on the inland sea level has influenced the formation of several landscape features that are now targets for local or national landscape protection programs, and how a unified view could benefit the future of landscape policies in the whole region.

Allowances for evolving coastal flood risk under uncertain local sea-level rise

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buchanan, Maya K.; Kopp, Robert E.; Oppenheimer, Michael

Estimates of future flood hazards made under the assumption of stationary mean sea level are biased low due to sea-level rise (SLR). However, adjustments to flood return levels made assuming fixed increases of sea level are also inadequate when applied to sea level that is rising over time at an uncertain rate. SLR allowances—the height adjustment from historic flood levels that maintain under uncertainty the annual expected probability of flooding—are typically estimated independently of individual decision-makers’ preferences, such as time horizon, risk tolerance, and confidence in SLR projections.We provide a framework of SLR allowances that employs complete probability distributions ofmore » local SLR and a range of user-defined flood risk management preferences. Given non-stationary and uncertain sea-level rise, these metrics provide estimates of flood protection heights and offsets for different planning horizons in coastal areas. In conclusion, we illustrate the calculation of various allowance types for a set of long-duration tide gauges along U.S. coastlines.« less

Allowances for evolving coastal flood risk under uncertain local sea-level rise

DOE PAGES

Buchanan, Maya K.; Kopp, Robert E.; Oppenheimer, Michael; ...

2016-06-03

Estimates of future flood hazards made under the assumption of stationary mean sea level are biased low due to sea-level rise (SLR). However, adjustments to flood return levels made assuming fixed increases of sea level are also inadequate when applied to sea level that is rising over time at an uncertain rate. SLR allowances—the height adjustment from historic flood levels that maintain under uncertainty the annual expected probability of flooding—are typically estimated independently of individual decision-makers’ preferences, such as time horizon, risk tolerance, and confidence in SLR projections.We provide a framework of SLR allowances that employs complete probability distributions ofmore » local SLR and a range of user-defined flood risk management preferences. Given non-stationary and uncertain sea-level rise, these metrics provide estimates of flood protection heights and offsets for different planning horizons in coastal areas. In conclusion, we illustrate the calculation of various allowance types for a set of long-duration tide gauges along U.S. coastlines.« less

Investigating Future Climate Scenarios

ERIC Educational Resources Information Center

Dempsey, Chris; Bodzin, Alec; Anastasio, David; Sahagian, Dork; Cirucci, Lori

2012-01-01

One of the most alarming impacts of projected climate change is a significant rise in sea level. Sea level has varied by hundreds of meters over geologic time, yet these changes have generally been slow paced, allowing ecosystems to adjust to changing land surface and marine habitats. Since the Industrial Revolution, anthropogenic emissions have…

Potential sea-level rise impacts on tidal wetlands in the Pacific Northwest: Declines in productivity and diversity?

EPA Science Inventory

Global climate change could alter sea-level and salinity dynamics in Pacific Northwest estuaries. We combined survey and experimental approaches to better understand potential climate change effects on the future of tidal wetland primary producers in the region. Surveys conducte...

Probabilistic Projections of Future Sea-Level Change and Their Implications for Flood Risk Management: Insights from the American Climate Prospectus

NASA Astrophysics Data System (ADS)

Kopp, R. E., III; Delgado, M.; Horton, R. M.; Houser, T.; Little, C. M.; Muir-Wood, R.; Oppenheimer, M.; Rasmussen, D. M., Jr.; Strauss, B.; Tebaldi, C.

2014-12-01

Global mean sea level (GMSL) rise projections are insufficient for adaptation planning; local decisions require local projections that characterize risk over a range of timeframes and tolerances. We present a global set of local sea level (LSL) projections to inform decisions on timescales ranging from the coming decades through the 22nd century. We present complete probability distributions, informed by a combination of expert community assessment, expert elicitation, and process modeling [1]. We illustrate the application of this framework by estimating the joint distribution of future sea-level change and coastal flooding, and associated economic costs [1,2]. In much of the world in the current century, differences in median LSL projections are due primarily to varying levels of non-climatic uplift or subsidence. In the 22nd century and in the high-end tails, larger ice sheet contributions, particularly from the Antarctic ice sheet (AIS), contribute significantly to site-to-site differences. Uncertainty in GMSL and most LSL projections is dominated by the uncertain AIS component. Sea-level rise dramatically reshapes flood risk. For example, at the New York City (Battery) tide gauge, our projections indicate a likely (67% probability) 21st century LSL rise under RCP 8.5 of 65--129 cm (1-in-20 chance of exceeding 154 cm). Convolving the distribution of projected sea-level rise with the extreme value distribution of flood return periods indicates that this rise will cause the current 1.80 m `1-in-100 year' flood event to occur an expected nine times over the 21st century -- equivalent to the expected number of `1-in-11 year' floods in the absence of sea-level change. Projected sea-level rise for 2100 under RCP 8.5 would likely place 80-160 billion of current property in New York below the high tide line, with a 1-in-20 chance of losses >190 billion. Even without accounting for potential changes in storms themselves, it would likely increase average annual storm damage by 2.6-5.2 billion (1-in-20 chance of >7 billion). Projected increases in tropical cyclone intensity would further increase damages [2]. References: [1] R. E. Kopp et al. (2014), Earth's Future, doi:10.1002/2014EF000239. [2] T. Houser et al. (2014), American Climate Prospectus, www.climateprospectus.org.

Current & future vulnerability of sarasota county Florida to hurricane storm surge & sea level rise

USGS Publications Warehouse

Frazier, T.; Wood, N.; Yarnal, B.

2008-01-01

Coastal communities in portions of the United States are vulnerable to storm-surge inundation from hurricanes and this vulnerability will likely increase, given predicted rises in sea level from climate change and growing coastal development. In this paper, we provide an overview of research to determine current and future societal vulnerability to hurricane storm-surge inundation and to help public officials and planners integrate these scenarios into their long-range land use plans. Our case study is Sarasota County, Florida, where planners face the challenge of balancing increasing population growth and development with the desire to lower vulnerability to storm surge. Initial results indicate that a large proportion of Sarasota County's residential and employee populations are in areas prone to storm-surge inundation from a Category 5 hurricane. This hazard zone increases when accounting for potential sea-level-rise scenarios, thereby putting additional populations at risk. Subsequent project phases involve the development of future land use and vulnerability scenarios in collaboration with local officials. Copyright ASCE 2008.

Under-estimated wave contribution to coastal sea-level rise

NASA Astrophysics Data System (ADS)

Melet, Angélique; Meyssignac, Benoit; Almar, Rafael; Le Cozannet, Gonéri

2018-03-01

Coastal communities are threatened by sea-level changes operating at various spatial scales; global to regional variations are associated with glacier and ice sheet loss and ocean thermal expansion, while smaller coastal-scale variations are also related to atmospheric surges, tides and waves. Here, using 23 years (1993-2015) of global coastal sea-level observations, we examine the contribution of these latter processes to long-term sea-level rise, which, to date, have been relatively less explored. It is found that wave contributions can strongly dampen or enhance the effects of thermal expansion and land ice loss on coastal water-level changes at interannual-to-multidecadal timescales. Along the US West Coast, for example, negative wave-induced trends dominate, leading to negative net water-level trends. Accurate estimates of past, present and future coastal sea-level rise therefore need to consider low-frequency contributions of wave set-up and swash.

Coralgal reef morphology records punctuated sea-level rise during the last deglaciation.

PubMed

Khanna, Pankaj; Droxler, André W; Nittrouer, Jeffrey A; Tunnell, John W; Shirley, Thomas C

2017-10-19

Coralgal reefs preserve the signatures of sea-level fluctuations over Earth's history, in particular since the Last Glacial Maximum 20,000 years ago, and are used in this study to indicate that punctuated sea-level rise events are more common than previously observed during the last deglaciation. Recognizing the nature of past sea-level rises (i.e., gradual or stepwise) during deglaciation is critical for informing models that predict future vertical behavior of global oceans. Here we present high-resolution bathymetric and seismic sonar data sets of 10 morphologically similar drowned reefs that grew during the last deglaciation and spread 120 km apart along the south Texas shelf edge. Herein, six commonly observed terrace levels are interpreted to be generated by several punctuated sea-level rise events forcing the reefs to shrink and backstep through time. These systematic and common terraces are interpreted to record punctuated sea-level rise events over timescales of decades to centuries during the last deglaciation, previously recognized only during the late Holocene.

Holocene key coral species in the Northwest Pacific: indicators of reef formation and reef ecosystem responses to global climate change and anthropogenic stresses in the near future

NASA Astrophysics Data System (ADS)

Hongo, Chuki

2012-03-01

The geological record of key coral species that contribute to reef formation and maintenance of reef ecosystems is important for understanding the ecosystem response to global-scale climate change and anthropogenic stresses in the near future. Future responses can be predicted from accumulated data on Holocene reef species identified in drillcore and from data on raised reef terraces. The present study analyzes a dataset based on 27 drillcores, raised reef terraces, and 134 radiocarbon and U-Th ages from reefs of the Northwest Pacific, with the aim of examining the role of key coral species in reef growth and maintenance for reef ecosystem during Holocene sea-level change. The results indicate a latitudinal change in key coral species: arborescent Acropora (Acropora intermedia and Acropora muricata) was the dominant reef builder at reef crests in the tropics, whereas Porites (Porites australiensis, Porites lutea, and Porites lobata) was the dominant contributor to reef growth in the subtropics between 10,000 and 7000 cal. years BP (when the rate of sea-level rise was 10 m/ka). Acropora digitifera, Acropora hyacinthus, Acropora robusta/A. abrotanoides, Isopora palifera, Favia stelligera, and Goniastrea retiformis from the corymbose and tabular Acropora facies were the main key coral species at reef crests between 7000 and 5000 cal. years BP (when the rate of sea-level rise was 5 m/ka) and during the following period of stable sea-level. Massive Porites (P. australiensis, P. lutea, and P. lobata) contributed to reef growth in shallow lagoons during the period of stable sea level. Key coral species from the corymbose and tabular Acropora facies have the potential to build reefs and maintain ecosystems in the near future under a global sea-level rise of 2-6 m/ka, as do key coral species from the arborescent Acropora facies and massive Porites facies, which show vigorous growth and are tolerant to relatively deep-water, low-energy environments. However, these species are likely to experience severe mortality in upcoming decades due to natural and anthropogenic stresses. Consequently, this damage will lead to a collapse in reef formation and the maintenance of reef ecosystems in the near future. This study emphasizes the need for research into the conservation of key coral species.

Deep Uncertainty Surrounding Coastal Flood Risk Projections: A Case Study for New Orleans

NASA Astrophysics Data System (ADS)

Wong, Tony E.; Keller, Klaus

2017-10-01

Future sea-level rise drives severe risks for many coastal communities. Strategies to manage these risks hinge on a sound characterization of the uncertainties. For example, recent studies suggest that large fractions of the Antarctic ice sheet (AIS) may rapidly disintegrate in response to rising global temperatures, leading to potentially several meters of sea-level rise during the next few centuries. It is deeply uncertain, for example, whether such an AIS disintegration will be triggered, how much this would increase sea-level rise, whether extreme storm surges intensify in a warming climate, or which emissions pathway future societies will choose. Here, we assess the impacts of these deep uncertainties on projected flooding probabilities for a levee ring in New Orleans, LA. We use 18 scenarios, presenting probabilistic projections within each one, to sample key deeply uncertain future projections of sea-level rise, radiative forcing pathways, storm surge characterization, and contributions from rapid AIS mass loss. The implications of these deep uncertainties for projected flood risk are thus characterized by a set of 18 probability distribution functions. We use a global sensitivity analysis to assess which mechanisms contribute to uncertainty in projected flood risk over the course of a 50-year design life. In line with previous work, we find that the uncertain storm surge drives the most substantial risk, followed by general AIS dynamics, in our simple model for future flood risk for New Orleans.

Sea level change: lessons from the geologic record

USGS Publications Warehouse

,

1995-01-01

Rising sea level is potentially one of the most serious impacts of climatic change. Even a small sea level rise would have serious economic consequences because it would cause extensive damage to the world's coastal regions. Sea level can rise in the future because the ocean surface can expand due to warming and because polar ice sheets and mountain glaciers can melt, increasing the ocean's volume of water. Today, ice caps on Antarctica and Greenland contain 91 and 8 percent of the world's ice, respectively. The world's mountain glaciers together contain only about 1 percent. Melting all this ice would raise sea level about 80 meters. Although this extreme scenario is not expected, geologists know that sea level can rise and fall rapidly due to changing volume of ice on continents. For example, during the last ice age, about 18,000 years ago, continental ice sheets contained more than double the modem volume of ice. As ice sheets melted, sea level rose 2 to 3 meters per century, and possibly faster during certain times. During periods in which global climate was very warm, polar ice was reduced and sea level was higher than today.

Ice2sea - Estimating the future contribution of continental ice to sea-level rise - project summary

NASA Astrophysics Data System (ADS)

Ford, Elaina; Vaughan, David

2013-04-01

Ice2sea brings together the EU's scientific and operational expertise from 24 leading institutions across Europe and beyond. Improved projections of the contribution of ice to sea-level rise produced by this major European-funded programme will inform the fifth IPCC report (due in September 2013). In 2007, the fourth Intergovernmental Panel on Climate Change (IPCC) report highlighted ice-sheets as the most significant remaining uncertainty in projections of sea-level rise. Understanding about the crucial ice-sheet effects was "too limited to assess their likelihood or provide a best estimate of an upper bound for sea-level rise". Ice2sea was created to address these issues - the project started in 2009 and is now drawing to a close, with our final symposium in May 2013, and final publicity activities around the IPCC report release in autumn 2013. Here we present a summary of the overall and key outputs of the ice2sea project.

Evaluation of the effects of sea-level change and coastal canal management on saltwater intrusion in the Biscayne aquifer of south Florida, USA

NASA Astrophysics Data System (ADS)

Hughes, J. D.; Sifuentes, D. F.; White, J.

2015-12-01

Sea-level increases are expected to have an effect on the position of the freshwater-saltwater interface in the Biscayne aquifer in south Florida as a result of the low topographic relief of the area and high rates of groundwater withdrawal from the aquifer. To study the effects that future sea-level increases will have on saltwater intrusion in the Biscayne aquifer in Broward County, Florida, a three-dimensional, variable-density, groundwater-flow and transport model was developed. The model was calibrated to observed groundwater heads and chloride concentrations for a 62-year period that includes historic increases in sea level, development of a surface-water management system to control flooding, and increases in groundwater withdrawals as the area transitioned from agricultural to urban land uses. Sensitivity analyses indicate that downward leakage of saltwater from coastal canals and creeks was the primary source of saltwater to the Biscayne aquifer during the last 62-years in areas where the surface-water system is not actively managed and is tidally influenced. In areas removed from the coastal canals and creeks or under active surface-water management, historic groundwater withdrawals were the primary cause of saltwater intrusion into the aquifer. Simulation of future conditions suggests that possible increases in sea level will result in additional saltwater intrusion. Model scenarios suggest that additional saltwater intrusion will be greatest in areas where coastal canals and creeks were historically the primary source of seawater. Future saltwater intrusion in those areas, however, may be reduced by relocation of salinity-control structures.

Coastal marsh response to historical and future sea-level acceleration

USGS Publications Warehouse

Kirwan, M.; Temmerman, S.

2009-01-01

We consider the response of marshland to accelerations in the rate of sea-level rise by utilizing two previously described numerical models of marsh elevation. In a model designed for the Scheldt Estuary (Belgium-SW Netherlands), a feedback between inundation depth and suspended sediment concentrations allows marshes to quickly adjust their elevation to a change in sea-level rise rate. In a model designed for the North Inlet Estuary (South Carolina), a feedback between inundation and vegetation growth allows similar adjustment. Although the models differ in their approach, we find that they predict surprisingly similar responses to sea-level change. Marsh elevations adjust to a step change in the rate of sea-level rise in about 100 years. In the case of a continuous acceleration in the rate of sea-level rise, modeled accretion rates lag behind sea-level rise rates by about 20 years, and never obtain equilibrium. Regardless of the style of acceleration, the models predict approximately 6-14 cm of marsh submergence in response to historical sea-level acceleration, and 3-4 cm of marsh submergence in response to a projected scenario of sea-level rise over the next century. While marshes already low in the tidal frame would be susceptible to these depth changes, our modeling results suggest that factors other than historical sea-level acceleration are more important for observations of degradation in most marshes today.

Effects of sea-level rise on salt water intrusion near a coastal well field in southeastern Florida

USGS Publications Warehouse

Langevin, Christian D.; Zygnerski, Michael

2013-01-01

A variable-density groundwater flow and dispersive solute transport model was developed for the shallow coastal aquifer system near a municipal supply well field in southeastern Florida. The model was calibrated for a 105-year period (1900 to 2005). An analysis with the model suggests that well-field withdrawals were the dominant cause of salt water intrusion near the well field, and that historical sea-level rise, which is similar to lower-bound projections of future sea-level rise, exacerbated the extent of salt water intrusion. Average 2005 hydrologic conditions were used for 100-year sensitivity simulations aimed at quantifying the effect of projected rises in sea level on fresh coastal groundwater resources near the well field. Use of average 2005 hydrologic conditions and a constant sea level result in total dissolved solids (TDS) concentration of the well field exceeding drinking water standards after 70 years. When sea-level rise is included in the simulations, drinking water standards are exceeded 10 to 21 years earlier, depending on the specified rate of sea-level rise.

Analysis of present and future potential compound flooding risk along the European coast

NASA Astrophysics Data System (ADS)

Bevacqua, Emanuele; Maraun, Douglas; Voukouvalas, Evangelos; Vousdoukas, Michalis I.; Widmann, Martin; Manning, Colin; Vrac, Mathieu

2017-04-01

The coastal zone is the natural border between the sea and the mainland, and it is constantly under the influence of marine and land-based natural and human-induced pressure. Compound floods are extreme events occurring in coastal areas where the interaction of joint high sea level and large amount of precipitation causes extreme floodings. Typically the risk of flooding in coastal areas is defined analysing either sea level or precipitation driven floodings, however compound floods should be considered to avoid an underestimation of the risk. In the future, the human pressure at the coastal zone is expected to increase, urging for a comprehensive analysis of the compound flooding risk under different climate change scenarios. In this study we introduce the concept of "potential risk" as we investigate how often large amount of precipitation and high sea level may co-occur, and not the effective impact due to the interaction of these two hazards. The effective risk of compound flooding in a specific place depends also on the local orography and on the existing protections. The estimation of the potential risk of compound flooding is useful to individuate places where an effective risk of compound flooding may exist, and where further studies would be useful to get more precise information on the local risk. We estimate the potential risk of compound flooding along the European coastal zone incorporating the ERA-Interim meteorological reanalysis for the past and present state, and the future projections from two RCP scenarios (namely the RCP4.5 and RCP8.5 scenarios) as derived from 8 CMIP5 models of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Sea level data are estimated by forcing the hydrodynamic model Delft3D-Flow with 6-hourly wind and atmospheric pressure fields. Based on sea level (storm surge and astronomical tide) and precipitation joint occurrence analysis, a map of the potential compound flooding risk along the European coast is proposed and critical places with high potential risk are identified. For these critical places, we plan to asses the potential compound flood risk driven by coinciding extreme values of sea level and river discharge. Finally, we analyse the atmospheric large scale processes that lead to compound floods and their variation under future climate change scenarios.

Committed sea-level rise for the next century from Greenland ice sheet dynamics during the past decade

PubMed Central

Price, Stephen F.; Payne, Antony J.; Howat, Ian M.; Smith, Benjamin E.

2011-01-01

We use a three-dimensional, higher-order ice flow model and a realistic initial condition to simulate dynamic perturbations to the Greenland ice sheet during the last decade and to assess their contribution to sea level by 2100. Starting from our initial condition, we apply a time series of observationally constrained dynamic perturbations at the marine termini of Greenland’s three largest outlet glaciers, Jakobshavn Isbræ, Helheim Glacier, and Kangerdlugssuaq Glacier. The initial and long-term diffusive thinning within each glacier catchment is then integrated spatially and temporally to calculate a minimum sea-level contribution of approximately 1 ± 0.4 mm from these three glaciers by 2100. Based on scaling arguments, we extend our modeling to all of Greenland and estimate a minimum dynamic sea-level contribution of approximately 6 ± 2 mm by 2100. This estimate of committed sea-level rise is a minimum because it ignores mass loss due to future changes in ice sheet dynamics or surface mass balance. Importantly, > 75% of this value is from the long-term, diffusive response of the ice sheet, suggesting that the majority of sea-level rise from Greenland dynamics during the past decade is yet to come. Assuming similar and recurring forcing in future decades and a self-similar ice dynamical response, we estimate an upper bound of 45 mm of sea-level rise from Greenland dynamics by 2100. These estimates are constrained by recent observations of dynamic mass loss in Greenland and by realistic model behavior that accounts for both the long-term cumulative mass loss and its decay following episodic boundary forcing. PMID:21576500

Committed sea-level rise for the next century from Greenland ice sheet dynamics during the past decade.

PubMed

Price, Stephen F; Payne, Antony J; Howat, Ian M; Smith, Benjamin E

2011-05-31

We use a three-dimensional, higher-order ice flow model and a realistic initial condition to simulate dynamic perturbations to the Greenland ice sheet during the last decade and to assess their contribution to sea level by 2100. Starting from our initial condition, we apply a time series of observationally constrained dynamic perturbations at the marine termini of Greenland's three largest outlet glaciers, Jakobshavn Isbræ, Helheim Glacier, and Kangerdlugssuaq Glacier. The initial and long-term diffusive thinning within each glacier catchment is then integrated spatially and temporally to calculate a minimum sea-level contribution of approximately 1 ± 0.4 mm from these three glaciers by 2100. Based on scaling arguments, we extend our modeling to all of Greenland and estimate a minimum dynamic sea-level contribution of approximately 6 ± 2 mm by 2100. This estimate of committed sea-level rise is a minimum because it ignores mass loss due to future changes in ice sheet dynamics or surface mass balance. Importantly, > 75% of this value is from the long-term, diffusive response of the ice sheet, suggesting that the majority of sea-level rise from Greenland dynamics during the past decade is yet to come. Assuming similar and recurring forcing in future decades and a self-similar ice dynamical response, we estimate an upper bound of 45 mm of sea-level rise from Greenland dynamics by 2100. These estimates are constrained by recent observations of dynamic mass loss in Greenland and by realistic model behavior that accounts for both the long-term cumulative mass loss and its decay following episodic boundary forcing.

Black Sea outflow response to Holocene meltwater events.

PubMed

Herrle, Jens O; Bollmann, Jörg; Gebühr, Christina; Schulz, Hartmut; Sheward, Rosie M; Giesenberg, Annika

2018-03-06

During the Holocene, North American ice sheet collapse and rapid sea-level rise reconnected the Black Sea with the global ocean. Rapid meltwater releases into the North Atlantic and associated climate change arguably slowed the pace of Neolithisation across southeastern Europe, originally hypothesized as a catastrophic flooding that fueled culturally-widespread deluge myths. However, we currently lack an independent record linking the timing of meltwater events, sea-level rise and environmental change with the timing of Neolithisation in southeastern Europe. Here, we present a sea surface salinity record from the Northern Aegean Sea indicative of two meltwater events at ~8.4 and ~7.6 kiloyears that can be directly linked to rapid declines in the establishment of Neolithic sites in southeast Europe. The meltwater events point to an increased outflow of low salinity water from the Black Sea driven by rapid sea level rise >1.4 m following freshwater outbursts from Lake Agassiz and the final decay of the Laurentide ice sheet. Our results shed new light on the link between catastrophic sea-level rise and the Neolithisation of southeastern Europe, and present a historical example of how coastal populations could have been impacted by future rapid sea-level rise.

Development of a Geographic Information System (GIS) tool for the preliminary assessment of the effects of predicted sea level and tidal change on transportation infrastructure.

DOT National Transportation Integrated Search

2013-09-01

In this project, researchers from the University of Florida developed a sketch planning tool that can be used to conduct statewide and regional assessments of transportation facilities potentially vulnerable to sea level change trends. Possible futur...

A heuristic evaluation of long-term global sea level acceleration

NASA Astrophysics Data System (ADS)

Spada, Giorgio; Olivieri, Marco; Galassi, Gaia

2015-05-01

In view of the scientific and social implications, the global mean sea level rise (GMSLR) and its possible causes and future trend have been a challenge for so long. For the twentieth century, reconstructions generally indicate a rate of GMSLR in the range of 1.5 to 2.0 mm yr-1. However, the existence of nonlinear trends is still debated, and current estimates of the secular acceleration are subject to ample uncertainties. Here we use various GMSLR estimates published on scholarly journals since the 1940s for a heuristic assessment of global sea level acceleration. The approach, alternative to sea level reconstructions, is based on simple statistical methods and exploits the principles of meta-analysis. Our results point to a global sea level acceleration of 0.54 ± 0.27 mm/yr/century (1σ) between 1898 and 1975. This supports independent estimates and suggests that a sea level acceleration since the early 1900s is more likely than currently believed.

Comparing the role of absolute sea-level rise and vertical tectonic motions in coastal flooding, Torres Islands (Vanuatu)

NASA Astrophysics Data System (ADS)

Ballu, Valérie; Bouin, Marie-Noëlle; Siméoni, Patricia; Crawford, Wayne C.; Calmant, Stephane; Boré, Jean-Michel; Kanas, Tony; Pelletier, Bernard

2011-08-01

Since the late 1990s, rising sea levels around the Torres Islands (north Vanuatu, southwest Pacific) have caused strong local and international concern. In 2002-2004, a village was displaced due to increasing sea incursions, and in 2005 a United Nations Environment Programme press release referred to the displaced village as perhaps the world's first climate change "refugees." We show here that vertical motions of the Torres Islands themselves dominate the apparent sea-level rise observed on the islands. From 1997 to 2009, the absolute sea level rose by 150 + /-20 mm. But GPS data reveal that the islands subsided by 117 + /-30 mm over the same time period, almost doubling the apparent gradual sea-level rise. Moreover, large earthquakes that occurred just before and after this period caused several hundreds of mm of sudden vertical motion, generating larger apparent sea-level changes than those observed during the entire intervening period. Our results show that vertical ground motions must be accounted for when evaluating sea-level change hazards in active tectonic regions. These data are needed to help communities and governments understand environmental changes and make the best decisions for their future.

Comparing the role of absolute sea-level rise and vertical tectonic motions in coastal flooding, Torres Islands (Vanuatu).

PubMed

Ballu, Valérie; Bouin, Marie-Noëlle; Siméoni, Patricia; Crawford, Wayne C; Calmant, Stephane; Boré, Jean-Michel; Kanas, Tony; Pelletier, Bernard

2011-08-09

Since the late 1990s, rising sea levels around the Torres Islands (north Vanuatu, southwest Pacific) have caused strong local and international concern. In 2002-2004, a village was displaced due to increasing sea incursions, and in 2005 a United Nations Environment Programme press release referred to the displaced village as perhaps the world's first climate change "refugees." We show here that vertical motions of the Torres Islands themselves dominate the apparent sea-level rise observed on the islands. From 1997 to 2009, the absolute sea level rose by 150 + /-20 mm. But GPS data reveal that the islands subsided by 117 + /-30 mm over the same time period, almost doubling the apparent gradual sea-level rise. Moreover, large earthquakes that occurred just before and after this period caused several hundreds of mm of sudden vertical motion, generating larger apparent sea-level changes than those observed during the entire intervening period. Our results show that vertical ground motions must be accounted for when evaluating sea-level change hazards in active tectonic regions. These data are needed to help communities and governments understand environmental changes and make the best decisions for their future.

Arctic Sea Ice in a 1.5°C Warmer World

NASA Astrophysics Data System (ADS)

Niederdrenk, Anne Laura; Notz, Dirk

2018-02-01

We examine the seasonal cycle of Arctic sea ice in scenarios with limited future global warming. To do so, we analyze two sets of observational records that cover the observational uncertainty of Arctic sea ice loss per degree of global warming. The observations are combined with 100 simulations of historical and future climate evolution from the Max Planck Institute Earth System Model Grand Ensemble. Based on the high-sensitivity observations, we find that Arctic September sea ice is lost with low probability (P≈ 10%) for global warming of +1.5°C above preindustrial levels and with very high probability (P> 99%) for global warming of +2°C above preindustrial levels. For the low-sensitivity observations, September sea ice is extremely unlikely to disappear for +1.5°C warming (P≪ 1%) and has low likelihood (P≈ 10%) to disappear even for +2°C global warming. For March, both observational records suggest a loss of 15% to 20% of Arctic sea ice area for 1.5°C to 2°C global warming.

Quantifying and Projecting Relative Sea-Level Rise in The Deltaic Regions

NASA Astrophysics Data System (ADS)

Shum, C. K.; Chung-Yen, K.; Calmant, S.; Yang, T. Y.; Guo, Q.; Jia, Y.; Ballu, V.; Guo, J.; Karptychev, M.; Krien, Y.; Kusche, J.; Tseng, K. H.; Wan, J.; Uebbing, B.

2017-12-01

Half of the world's population lives within 200 km of coastlines. Accelerated sea-level rise, compounded by effects of population growth, severe land subsidence due to fluvial sediment compaction/load, and anthropogenic oil and natural gas and ground water extraction, tectonic motion, and the increasing threat of more intense and more frequent cyclone-driven storm surges, have exacerbated the vulnerability of many of world's deltaic regions, including the Bangladesh and the Mississippi River Deltas. At present, understanding and quantifying the natural and anthropogenic processes governing these solid Earth vertical motion processes remain elusive to enable addressing coastal vulnerability due to current and future projection of relative sea-level rise for deltaic regions at the regional scales. Bangladesh, a low-lying and one of the most densely populated countries in the world located at the Bay of Bengal, is prone to transboundary monsoonal flooding, and is believed to be aggravated by more frequent and intensified cyclones resulting from anthropogenic climate change. The Mississippi River Deltaic region has been severely subsiding due primarily to fluvial sediment compaction and load during the last 10 centuries, oil/gas and groundwater extractions, and commercial developments, making it vulnerable to sea-level rise hazards. Here we present results of global geocentric sea-level rise, 1950-2016, separating vertical land motion at global tide gauge datum, by integrating tide gauge and radar altimeter records in a novel sea-level reconstruction scheme, focusing on the Mississippi River and the Bangladesh Deltas. We then integrate the resulting sea level estimates with historic imageries, GPS and InSAR data, as well as sediment isostatic and load model predicted present-day land subsidence, to constrain the 3D land motion to study the impacts of various scenarios of future relative sea level projections on the Bangladesh Delta to the end of the 21st Century and beyond.

Sea level: measuring the bounding surfaces of the ocean.

PubMed

Tamisiea, Mark E; Hughes, Chris W; Williams, Simon D P; Bingley, Richard M

2014-09-28

The practical need to understand sea level along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global sea level. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of sea-level rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in sea level. While information from many scientific disciplines is needed to understand sea-level change, this review focuses on contributions from geodesy and the role of the ocean's bounding surfaces: the sea surface and the Earth's crust. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Incorporating future change into current conservation planning: Evaluating tidal saline wetland migration along the U.S. Gulf of Mexico coast under alternative sea-level rise and urbanization scenarios

USGS Publications Warehouse

Enwright, Nicholas M.; Griffith, Kereen T.; Osland, Michael J.

2015-11-02

In this study, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, quantified the potential for landward migration of tidal saline wetlands along the U.S. Gulf of Mexico coast under alternative future sea-level rise and urbanization scenarios. Our analyses focused exclusively on tidal saline wetlands (that is, mangrove forests, salt marshes, and salt flats), and we combined these diverse tidal saline wetland ecosystems into a single grouping, “tidal saline wetland.” Collectively, our approach and findings can provide useful information for scientists and environmental planners working to develop future-focused adaptation strategies for conserving coastal landscapes and the ecosystem goods and services provided by tidal saline wetlands. The primary product of this work is a public dataset that identifies locations where landward migration of tidal saline wetlands is expected to occur under alternative future sea-level rise and urbanization scenarios. In addition to identifying areas where landward migration of tidal saline wetlands is possible because of the absence of barriers, these data also identify locations where landward migration of these wetlands could be prevented by barriers associated with current urbanization, future urbanization, and levees.

Increasing Influence of Societal Response Variables in Coastal Evolution Projections (Invited)

NASA Astrophysics Data System (ADS)

Gayes, P. T.; McCoy, C. A.; Pietrafesa, L. J.

2010-12-01

Recent efforts to project changes in coastal erosion and vulnerability of the state of South Carolina’s (SC’s) oceanfront for different scenarios of future sea level have reinforced the significance of the influence of societal modifications and response to past and anticipated coastal change in these systems. For large reaches of the SC coast human interactions have been a dominant signal driving coastal change across annual to decadal scales. Over the last 20 years, SC’s shoreline has been advanced seawards in many areas due to a combination of sustained societal commitment to beach nourishment and to a lull in atmospheric storms; reversing the long-term erosional trend of shoreline change. Adjacent areas not yet threatened or where coastal defense is unsupported economically have continued to migrate landwards. Locally, efforts focused on stabilizing the subaerial beach have not moderated long-term shoreward migration of the shoreface changing the overall morphology of the coastal boundary waves and currents are operating against. These societal effects, coupled with realistic, substative assessments of future atmospheric storm activity and sea level variability, both over scales of seasons to multi-decades, require consideration to realistically project future coastal behavior across time and spatial scales for planning and resource management. As with future climate and sea level variability effects on the shoreline, the scale and intensity of societal response is not static or precisely projected spatially and temporally into the future. With continued expansion of coastal development and erosion into previously lightly developed and defended coastal areas, societal influences should be expected to increase. Increasing cost of larger scale defenses will likely drive pressure for hardened structures to enhance ”softer” nourishment strategies. However, this strategy would further modify the ability of nature to respond to natural forces. Nourishment programs are strongly cyclic and can act in or out of phase with natural cyclic (inlet migration, sea level variability) or stochastic (storms) drivers with significant effects on coastal response and predictions of coastal behavior. Economic cycles and events may similarly moderate timing and scale of coastal defense relative to natural drivers. Societal decisions to not, enhance and or even abandon and remove existing engineering structures as future forces and costs increase, can result in a disproportional response and potentially failure of a section of coast. Some communities have expressed confidence in the ability to maintain the oceanfront shoreline against most projections of sea level rise over the next 100 years. The long-term trend in sea level change may be less important than naturally occurring regional scale, seasonal to inter-annual to multi-decadal variability in sea level; and these are complex but deterministic. There is less confidence, however, in the ability to combat passive submergence and associated flooding issues behind the immediate oceanfront. To the extent that may influence commitment to defend the oceanfront could strongly influence coastal behavior and stability in the long term.

Global mapping of nonseismic sea level oscillations at tsunami timescales.

PubMed

Vilibić, Ivica; Šepić, Jadranka

2017-01-18

Present investigations of sea level extremes are based on hourly data measured at coastal tide gauges. The use of hourly data restricts existing global and regional analyses to periods larger than 2 h. However, a number of processes occur at minute timescales, of which the most ruinous are tsunamis. Meteotsunamis, hazardous nonseismic waves that occur at tsunami timescales over limited regions, may also locally dominate sea level extremes. Here, we show that nonseismic sea level oscillations at tsunami timescales (<2 h) may substantially contribute to global sea level extremes, up to 50% in low-tidal basins. The intensity of these oscillations is zonally correlated with mid-tropospheric winds at the 99% significance level, with the variance doubling from the tropics and subtropics to the mid-latitudes. Specific atmospheric patterns are found during strong events at selected locations in the World Ocean, indicating a globally predominant generation mechanism. Our analysis suggests that these oscillations should be considered in sea level hazard assessment studies. Establishing a strong correlation between nonseismic sea level oscillations at tsunami timescales and atmospheric synoptic patterns would allow for forecasting of nonseismic sea level oscillations for operational use, as well as hindcasting and projection of their effects under past, present and future climates.

Global mapping of nonseismic sea level oscillations at tsunami timescales

PubMed Central

Vilibić, Ivica; Šepić, Jadranka

2017-01-01

Present investigations of sea level extremes are based on hourly data measured at coastal tide gauges. The use of hourly data restricts existing global and regional analyses to periods larger than 2 h. However, a number of processes occur at minute timescales, of which the most ruinous are tsunamis. Meteotsunamis, hazardous nonseismic waves that occur at tsunami timescales over limited regions, may also locally dominate sea level extremes. Here, we show that nonseismic sea level oscillations at tsunami timescales (<2 h) may substantially contribute to global sea level extremes, up to 50% in low-tidal basins. The intensity of these oscillations is zonally correlated with mid-tropospheric winds at the 99% significance level, with the variance doubling from the tropics and subtropics to the mid-latitudes. Specific atmospheric patterns are found during strong events at selected locations in the World Ocean, indicating a globally predominant generation mechanism. Our analysis suggests that these oscillations should be considered in sea level hazard assessment studies. Establishing a strong correlation between nonseismic sea level oscillations at tsunami timescales and atmospheric synoptic patterns would allow for forecasting of nonseismic sea level oscillations for operational use, as well as hindcasting and projection of their effects under past, present and future climates. PMID:28098195

How Fast? How Far? How Much? What We Need to Learn from the Past Behavior of Ice Sheets, and What They Might Not Tell Us

NASA Astrophysics Data System (ADS)

Alley, R. B.

2016-12-01

Paleoclimatic data support physical understanding that changes in ice sheets are primarily caused by changes in ocean temperature and in melting from above. With interesting qualifications, ice sheets tend to grow as accumulation rate in central regions drops into an ice age, and to shrink as accumulation rate rises. Changes in sea level may be influential but generally are too small and slow to be of primary importance. Thus, future atmospheric warming, oceanic warming and changes in oceanic circulation are especially important to future ice-sheet behavior. Paleoclimatic data support models and physical understanding that sustained warming beyond thresholds will cause progressively larger sea-level rise, up to quite high values, although the thresholds remain poorly quantified. Several indirect lines of evidence indicate great shrinkage or loss of parts or all of the Greenland ice sheet and marine sectors of the Antarctic ice sheet under warmth corresponding to CO2 levels similar to the modern or committed level. Despite this evidence, the state of the ice sheets during the most recent times warmer than today, including MIS 5e, remains unclear. The Greenland ice sheet did survive MIS 5e, but that may reflect warmth sufficient to remove the ice sheet but not sustained long enough to do so; greater warming in the future could cause much faster sea-level rise than generated in the past. Several indirect lines of evidence indicate that the marine basins of the West Antarctic Ice Sheet deglaciated during MIS 5e, and targeted field data could clarify this greatly. Physical understanding suggests, however, that even if this deglaciation did occur, it may have been slower than is possible in an even warmer future world; past rates of sea-level rise may define minimum rather than likely future rates.

Coastal Storm Hazards from Virginia to Maine

DTIC Science & Technology

2015-11-01

study, storm surge, tide, waves, wind, atmospheric pressure, and currents were the dominant storm responses computed. The effect of sea level change on...coastal storm hazards and vulnerability nationally (USACE 2015). NACCS goals also included evaluating the effect of future sea level change (SLC) on...the computed high-fidelity responses included storm surge, astronomical tide, waves, wave effects on water levels, storm duration, wind, currents

We Are All Engineers Now: Delivering Useful Projections Of Sea Level Rise

NASA Astrophysics Data System (ADS)

Pfeffer, W. T.

2011-12-01

Sea level rise is among the most tangible and potentially costly global changes facing society in the near future. Much of the uncertainty in future sea level rise lies in the determination of glacier and ice sheet contributions through melting of ice and through the discharge of icebergs directly into the ocean. As a consequence, many aspects of modern glaciological research have come to be motivated wholly or in part by the need to solve societally relevant problems involving future changes in sea level. To this extent, glaciology has become - temporarily - an applied science, in which the motivating questions are not purely scientific but practical in nature, and entail goals, deadlines and constraints that may or may not mesh comfortably with the skills, resources, and interests of the glaciological research community. This shift in motivation has subtle but important effects on how the glaciological community conducts research: we are no longer fully at liberty to explore only those problems that we judge to be the most intellectually stimulating and novel, or even the most likely to produce immediate results. We are obliged, at least if we are going to claim to be serving a critical societal need, to take on the entire spectrum of problems pertinent to sea level rise: the exciting with the mundane, the low-hanging fruit with the high-hanging, the tractable with the intractable. And in those intractable cases, and in other situations where the path to a solution is unclear, we must explore alternatives to our conventional approaches, and seek the means, if not to actually obtain solutions, to at least constrain the outcome and reduce the uncertainty of future knowledge. This broadening of methods is very much an engineer's approach to problem solving, but it also fits the philosopher/physicist P.W. Bridgman's definition of the scientific method as "Doing your damnedest, no holds barred."

Arctic Ocean Freshwater Content and Its Decadal Memory of Sea-Level Pressure

NASA Astrophysics Data System (ADS)

Johnson, Helen L.; Cornish, Sam B.; Kostov, Yavor; Beer, Emma; Lique, Camille

2018-05-01

Arctic freshwater content (FWC) has increased significantly over the last two decades, with potential future implications for the Atlantic meridional overturning circulation downstream. We investigate the relationship between Arctic FWC and atmospheric circulation in the control run of a coupled climate model. Multiple linear lagged regression is used to extract the response of total Arctic FWC to a hypothetical step increase in the principal components of sea-level pressure. The results demonstrate that the FWC adjusts on a decadal timescale, consistent with the idea that wind-driven ocean dynamics and eddies determine the response of Arctic Ocean circulation and properties to a change in surface forcing, as suggested by idealized models and theory. Convolving the response of FWC to a change in sea-level pressure with historical sea-level pressure variations reveals that the recent observed increase in Arctic FWC is related to natural variations in sea-level pressure.

Coastal sea level variability in the eastern English Channel: Potentialities for future SWOT applicability

NASA Astrophysics Data System (ADS)

Turki, Imen; Laignel, Benoit; Chevalier, Laetitia; Costa, Stephane

2014-05-01

Scientists and engineers need to understand the sea level variability in order to provide better estimates of the sea level rise for coastal defense using tide gauges and radar altimetry missions. The natural limitation of the tide gauge records is their geographical sparsity and confinement to coastlines. The future Surface Water and Ocean Topography (SWOT) mission will be launched in 2015 over a period of 5 years and will be designated to address this issue. This research was carried out in the framework of the program Surface Water and Ocean Topography (SWOT) which is a partnership between NASA and CNES. Using a series of statistical analyses, we point to characterize the sea level variability in the eastern English Channel (western France) from four tide gauges in Dunkirk, Dieppe, Le Havre and Cherbourg for the period 1964-2012. To assess the extent to which tide gauge point observations represent tide gauge data, we compare tide gauge records to SWOT measurements in their vicinity. Results have shown that the bimodality of the sea level, provided by the distribution analysis, can be reproduced by SWOT measurements with an overestimation of both modes and also the extreme values. The rate of the linear regression was also overestimated from 1.7-4 mm/yr to 2.6-5.4 mm/yr. The continuous wavelet transform of sea level records has shown the large-scale variability of annual (1-year band) and interannual cycles (2-6- and 6-12-year bands) in sea level, which can be explained by oceanographic and hydrological factors. High frequency dynamics of the sea level variability at short time-scales were extracted from SWOT measurements. They provide a good survey of the surge events (band of 3-4 months) and the spring-neap tidal cycle (band of 28 days). Then, tide gauges should be used in conjunction with satellite data to infer the full time-scale variability. Further studies are needed to refine the SWOT applicability in coastal areas. Key words: coastal zone, sea level variability, tide gauges, virtual SWOT measurements

Coastal inundation risk assessment due to subsidence and sea level rise in a Mediterranean alluvial plain (Volturno coastal plain - southern Italy)

NASA Astrophysics Data System (ADS)

Ciro Aucelli, Pietro Patrizio; Di Paola, Gianluigi; Incontri, Pietro; Rizzo, Angela; Vilardo, Giuseppe; Benassai, Guido; Buonocore, Berardino; Pappone, Gerardo

2017-11-01

Interdisciplinary studies of the last years highlight that the Italian coasts are significantly subject to retreat and to inundation by sea ingression due to natural and anthropic causes. In this study, the effects of future relative sea level have been evaluated for the Volturno River Plain, one of the widest coastal plain in southern Italy. The plain is characterized by high economical and ecological value, for the presence of farm activities, tourist structures and wetland protected zones. The study area is potentially prone to coastal flooding due to its very low topography and because it is affected by a severe subsidence, which emphasize the local effect of sea level rise due to the ongoing climate changes. In accordance with the guidelines of the MEDFLOOD project, the areas prone to inundation in the years 2065 and 2100 have been evaluated by comparing the future topographical information and expected relative sea level scenarios. The local Vertical Ground Displacements have been derived by PS-InSAR processing data whilst the mean values of the scenarios RCP 2.6 and RCP 8.5 provided by the IPCC (2014) have been used as future sea level projections in 2065 and 2100. The PS-InSar data elaboration shows that the area affected by subsidence corresponds to 35% of the Volturno plain and that the annual rate of the phenomenon ranges between -1 and -25 mm/yr. The inundation analysis, based on the classification of the areas in four hazard classes, indicates that in 2065 the zones located below the sea level will increase approximately of 50% respect to the present conditions, while between 2065 and 2100 the increase can be at least of 60% (IPCC, RCP 8.5 scenarios). Considering the socio-economical and ecological exposure, evaluated following the EUROSION project guidelines, the coastal flooding risk maps have been produced. Almost 8.2 km2 and 14.4 km2 of the investigated area has to be considered subject to very high marine inundation risk in 2065 and 2100, respectively.

Comment [on “Sea level rise shown to drive coastal erosion”

USGS Publications Warehouse

Sallenger,, Asbury H.; Morton, Robert; Fletcher, Charles; Thieler, E. Robert; Howd, Peter

2000-01-01

In a recent article (Eos, Trans., AGU, February 8, 2000, p.55), Leatherman et al. [2000] state that they have confirmed an association between sea-level rise and coastal erosion. Applying their results to the New Jersey, Delaware, and Maryland coasts and using a projected sea-level rise, the authors predict that by 2050 the shoreline will recede 60 m, about two times the average beach width. However, Leatherman et al. [2000] have not convincingly quantified a relationship between sea-level rise and shoreline erosion.We do not agree with their rationale for subsetting their data, and they have not considered other explanations for a background erosion along the U.S. east coast. Furthermore, their future projections are not supported by their analyses.

A NOAA/NOS Sea Level Advisory

NASA Astrophysics Data System (ADS)

Sweet, W.

2011-12-01

In order for coastal communities to realize current impacts and become resilient to future changes, sea level advisories/bulletins are necessary that systematically monitor and document non-tidal anomalies (residuals) and flood-watch (elevation) conditions. The need became apparent after an exceptional sea level anomaly along the U.S. East Coast in June - July of 2009 when higher than normal sea levels coincided with a perigean-spring tide and flooded many coastal regions. The event spurred numerous public inquiries to the National Oceanic and Atmospheric Administration's (NOAA) Center for Operational Oceanographic Products and Services (CO-OPS) from coastal communities concerned because of the lack of any coastal storm signatures normally associated with such an anomaly. A subsequent NOAA report provided insight into some of the mechanisms involved in the event and methods for tracking their reoccurrences. NOAA/CO-OPS is the U.S. authority responsible for defining sea level datums and tracking their relative changes in support of marine navigation and national and state land-use boundaries. These efforts are supported by the National Water Level Observation Network (NWLON), whose long-term and widespread observations largely define a total water level measurement impacting a coastal community. NWLON time series provide estimates of local relative sea level trends, a product increasingly utilized by various stakeholders planning for the future. NWLON data also capture significant short-term changes and conveyance of high-water variations (from surge to seasonal scale) provides invaluable insight into inundation patterns ultimately needed for a more comprehensive planning guide. A NOAA/CO-OPS Sea Level Advisory Project will enhance high-water monitoring capabilities by: - Automatically detecting sea level anomalies and flood-watch occurrences - Seasonally calibrating the anomaly thresholds to a locality in terms of flood potential - Alerting for near-term superposition of non-tidal residuals and large tide-range changes (i.e., spring tides). - Identifying important regional physical forcing mechanisms (both meteorological and oceanographic) to help explain the conditions - Displaying near-real time and archived information to establish a clear and direct communication with a community in regards to its past, present and future flood patterns. An example is presented for Charleston, SC, an area with little remaining free board in terms of its downtown infrastructure. The National Weather Service (NWS) issues multiple flood watches for Charleston every year that largely result from astronomical (earth-sun-moon system) tide forcing alone and NOAA's Coastal Services Center (CSC) often receives inquiries regarding downtown flooding during sunny, nondescript days. This project will allow for a deeper appreciation of surge-to-seasonal patterns of variability and compliment a community's living memory of sea level elevations/impacts needed to motivate societal adaptation as sea levels rise. Coordination with NWS's local Weather Forecasting Offices (WFO) is planned and the project will expand to other incident-prone regions once demonstration is accepted.

Probabilistic Estimates of Global Mean Sea Level and its Underlying Processes

NASA Astrophysics Data System (ADS)

Hay, C.; Morrow, E.; Kopp, R. E.; Mitrovica, J. X.

2015-12-01

Local sea level can vary significantly from the global mean value due to a suite of processes that includes ongoing sea-level changes due to the last ice age, land water storage, ocean circulation changes, and non-uniform sea-level changes that arise when modern-day land ice rapidly melts. Understanding these sources of spatial and temporal variability is critical to estimating past and present sea-level change and projecting future sea-level rise. Using two probabilistic techniques, a multi-model Kalman smoother and Gaussian process regression, we have reanalyzed 20th century tide gauge observations to produce a new estimate of global mean sea level (GMSL). Our methods allow us to extract global information from the sparse tide gauge field by taking advantage of the physics-based and model-derived geometry of the contributing processes. Both methods provide constraints on the sea-level contribution of glacial isostatic adjustment (GIA). The Kalman smoother tests multiple discrete models of glacial isostatic adjustment (GIA), probabilistically computing the most likely GIA model given the observations, while the Gaussian process regression characterizes the prior covariance structure of a suite of GIA models and then uses this structure to estimate the posterior distribution of local rates of GIA-induced sea-level change. We present the two methodologies, the model-derived geometries of the underlying processes, and our new probabilistic estimates of GMSL and GIA.

Keep up or drown: adjustment of western Pacific coral reefs to sea-level rise in the 21st century

PubMed Central

van Woesik, R.; Golbuu, Y.; Roff, G.

2015-01-01

Since the Mid-Holocene, some 5000 years ago, coral reefs in the Pacific Ocean have been vertically constrained by sea level. Contemporary sea-level rise is releasing these constraints, providing accommodation space for vertical reef expansion. Here, we show that Porites microatolls, from reef-flat environments in Palau (western Pacific Ocean), are ‘keeping up’ with contemporary sea-level rise. Measurements of 570 reef-flat Porites microatolls at 10 locations around Palau revealed recent vertical skeletal extension (78±13 mm) over the last 6–8 years, which is consistent with the timing of the recent increase in sea level. We modelled whether microatoll growth rates will potentially ‘keep up’ with predicted sea-level rise in the near future, based upon average growth, and assuming a decline in growth for every 1°C increase in temperature. We then compared these estimated extension rates with rates of sea-level rise under four Representative Concentration Pathways (RCPs). Our model suggests that under low–mid RCP scenarios, reef-coral growth will keep up with sea-level rise, but if greenhouse gas concentrations exceed 670 ppm atmospheric CO2 levels and with +2.2°C sea-surface temperature by 2100 (RCP 6.0 W m−2), our predictions indicate that Porites microatolls will be unable to keep up with projected rates of sea-level rise in the twenty-first century. PMID:26587277

Advanced Regional and Decadal Predictions of Coastal Inundation for the U.S. Atlantic and Gulf Coasts

NASA Astrophysics Data System (ADS)

Horton, B. P.; Donnelly, J. P.; Corbett, D. R.; Kemp, A.; Lindeman, K.; Mann, M. E.; Peltier, W. R.; Rahmstorf, S.

2012-12-01

Future inundation of the US Atlantic and Gulf coasts will depend upon both sea-level rise and the intensity and frequency of tropical cyclones, each of which will be affected by climate change. In this proposal, we will employ new interdisciplinary approaches to bring about a step change in the reliability of predictions of such inundation. The rate of sea-level rise along the US Atlantic and Gulf coasts has increased throughout the 20th century. Whilst there is widespread agreement that it continue to accelerate during the 21st century, great uncertainty surrounds its magnitude and geographic distribution. Key uncertainties include the role of continental ice sheets, mountain glaciers and ocean density changes. Insufficient understanding of these complex physical processes precludes accurate prediction of sea-level rise. New approaches using semi-empirical models that relate instrumental records of climate and sea-level rise have projected up to 2 m of sea-level rise by AD 2100. But the time span of instrumental sea-level records is insufficient to adequately constrain the climate:sea-level relationship. Here, we produce new high resolution proxy data of sea-level and temperature to provide crucial additional constraints to such semi-empirical models. Our dataset will span the alternation between the "Medieval Climate Anomaly" and "Little Ice Age". Before the models can provide appropriate data for coastal management and planning, they must be complemented with regional estimates of sea-level rise. Therefore, the proxy sea-level data has been collected from six study areas (Massachusetts, New Jersey, North Carolina, Georgia and Atlantic and Gulf coasts of Florida) to accommodate the required extent of regional variability. In the case of inundation arising from tropical cyclones, the historical and observational records are insufficient for predicting their nature and recurrence, because they are such extreme and rare events. Moreover, in the future, the resultant storm surges will be superimposed on background sea-level rise. To overcome these problems, we couple regional sea-level rise projections with hurricane simulations and storm surge models to map coastal inundation for the current climate and the best and worst case climate scenarios of the IPCC AR4. The products of this proposal will raise the bar for the scientific prediction of region-specific inundation probabilities in terms of coordinated semi-empirical proxy data, hindcast- and forecast-driven sea-level modeling and tropical cyclone forecasting. To optimize transfer of this often complex information for effective adaptive decision-making by managers and planners, we will systematically review >800 adaptation reports and consult early and often with primary endusers to identify their exact needs. We will produce high penetration print and web products for diverse audiences, specific to each region.

Climate Sensitivity Runs and Regional Hydrologic Modeling for Predicting the Response of the Greater Florida Everglades Ecosystem to Climate Change

NASA Astrophysics Data System (ADS)

Obeysekera, Jayantha; Barnes, Jenifer; Nungesser, Martha

2015-04-01

It is important to understand the vulnerability of the water management system in south Florida and to determine the resilience and robustness of greater Everglades restoration plans under future climate change. The current climate models, at both global and regional scales, are not ready to deliver specific climatic datasets for water resources investigations involving future plans and therefore a scenario based approach was adopted for this first study in restoration planning. We focused on the general implications of potential changes in future temperature and associated changes in evapotranspiration, precipitation, and sea levels at the regional boundary. From these, we developed a set of six climate and sea level scenarios, used them to simulate the hydrologic response of the greater Everglades region including agricultural, urban, and natural areas, and compared the results to those from a base run of current conditions. The scenarios included a 1.5 °C increase in temperature, ±10 % change in precipitation, and a 0.46 m (1.5 feet) increase in sea level for the 50-year planning horizon. The results suggested that, depending on the rainfall and temperature scenario, there would be significant changes in water budgets, ecosystem performance, and in water supply demands met. The increased sea level scenarios also show that the ground water levels would increase significantly with associated implications for flood protection in the urbanized areas of southeastern Florida.

Help, I don’t know which sea ice algorithm to use?!: Developing an authoritative sea ice climate data record

NASA Astrophysics Data System (ADS)

Meier, W.; Stroeve, J.; Duerr, R. E.; Fetterer, F. M.

2009-12-01

The declining Arctic sea ice is one of the most dramatic indicators of climate change and is being recognized as a key factor in future climate impacts on biology, human activities, and global climate change. As such, the audience for sea ice data is expanding well beyond the sea ice community. The most comprehensive sea ice data are from a series of satellite-borne passive microwave sensors. They provide a near-complete daily timeseries of sea ice concentration and extent since late-1978. However, there are many complicating issues in using such data, particularly for novice users. First, there is not one single, definitive algorithm, but several. And even for a given algorithm, different processing and quality-control methods may be used, depending on the source. Second, for all algorithms, there are uncertainties in any retrieved value. In general, these limitations are well-known: low spatial-resolution results in an imprecise ice edge determination and lack of small-scale detail (e.g., lead detection) within the ice pack; surface melt depresses concentration values during summer; thin ice is underestimated in some algorithms; some algorithms are sensitive to physical surface temperature; other surface features (e.g., snow) can influence retrieved data. While general error estimates are available for concentration values, currently the products do not carry grid-cell level or even granule level data quality information. Finally, metadata and data provenance information are limited, both of which are essential for future reprocessing. Here we describe the progress to date toward development of sea ice concentration products and outline the future steps needed to complete a sea ice climate data record.

Translating Uncertain Sea Level Projections Into Infrastructure Impacts Using a Bayesian Framework

NASA Astrophysics Data System (ADS)

Moftakhari, Hamed; AghaKouchak, Amir; Sanders, Brett F.; Matthew, Richard A.; Mazdiyasni, Omid

2017-12-01

Climate change may affect ocean-driven coastal flooding regimes by both raising the mean sea level (msl) and altering ocean-atmosphere interactions. For reliable projections of coastal flood risk, information provided by different climate models must be considered in addition to associated uncertainties. In this paper, we propose a framework to project future coastal water levels and quantify the resulting flooding hazard to infrastructure. We use Bayesian Model Averaging to generate a weighted ensemble of storm surge predictions from eight climate models for two coastal counties in California. The resulting ensembles combined with msl projections, and predicted astronomical tides are then used to quantify changes in the likelihood of road flooding under representative concentration pathways 4.5 and 8.5 in the near-future (1998-2063) and mid-future (2018-2083). The results show that road flooding rates will be significantly higher in the near-future and mid-future compared to the recent past (1950-2015) if adaptation measures are not implemented.

Sea-Level Rise and Land Subsidence in Deltas: Estimating Future Flood Risk Through Integrated Natural and Human System Modeling

NASA Astrophysics Data System (ADS)

Tessler, Z. D.; Vorosmarty, C. J.

2016-12-01

Deltas are highly sensitive to local human activities, land subsidence, regional water management, global sea-level rise, and climate extremes. We present a new delta flood exposure and risk framework for estimating the sensitivity of deltas to relative sea-level rise. We have applied this framework to a set of global environmental, geophysical, and social indicators over 48 major river deltas to quantify how contemporary risks vary across delta systems. The risk modeling framework incorporates upstream sediment flux and coastal land subsidence models, global empirical estimates of contemporary storm surge exposure, and population distribution and growth. Future scenarios are used to test the impacts on coastal flood risk of upstream dam construction, coastal population growth, accelerated sea-level rise, and enhanced storm surge. Results suggest a wide range of outcomes across different delta systems within each scenario. Deltas in highly engineered watersheds (Mississippi, Rhine) exhibit less sensitivity to increased dams due to saturation of sediment retention effects, though planned or under-construction dams are expected to have a substantial impact in the Yangtze, Irrawaddy, and Magdalena deltas. Population growth and sea-level rise are expected to be the dominant drivers of increased human risk in most deltas, with important exceptions in several countries, particularly China, where population are forecast to contract over the next several decades.

Effect of sea-level rise on salt water intrusion near a coastal well field in southeastern Florida.

PubMed

Langevin, Christian D; Zygnerski, Michael

2013-01-01

A variable-density groundwater flow and dispersive solute transport model was developed for the shallow coastal aquifer system near a municipal supply well field in southeastern Florida. The model was calibrated for a 105-year period (1900 to 2005). An analysis with the model suggests that well-field withdrawals were the dominant cause of salt water intrusion near the well field, and that historical sea-level rise, which is similar to lower-bound projections of future sea-level rise, exacerbated the extent of salt water intrusion. Average 2005 hydrologic conditions were used for 100-year sensitivity simulations aimed at quantifying the effect of projected rises in sea level on fresh coastal groundwater resources near the well field. Use of average 2005 hydrologic conditions and a constant sea level result in total dissolved solids (TDS) concentration of the well field exceeding drinking water standards after 70 years. When sea-level rise is included in the simulations, drinking water standards are exceeded 10 to 21 years earlier, depending on the specified rate of sea-level rise. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

Coastal vulnerability assessment of Olympic National Park to sea-level rise

USGS Publications Warehouse

Pendleton, Elizabeth A.; Hammar-Klose, Erika S.; Thieler, E. Robert; Williams, S. Jeffress

2004-01-01

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Olympic National Park (OLYM), Washington. The CVI scores the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, shoreline change rates, mean tidal range and mean wave height. The rankings for each variable were combined and an index value calculated for 1-minute grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. The Olympic National Park coast consists of rocky headlands, pocket beaches, glacial-fluvial features, and sand and gravel beaches. The Olympic coastline that is most vulnerable to sea-level rise are beaches in gently sloping areas.

Relative sea-level rise as indicated by gage data along the Mississippi and Alabama Gulf Coasts

USGS Publications Warehouse

Van Wilson, K.

2004-01-01

Global warming, or the increasing of earth's temperatures, leads to rising sea level as polar ice caps and mountain glaciers melt and ocean water undergoes thermal expansion. Tidal records collected by the U.S. Army Corps of Engineers (COE), Mobile District, at Gulfport, Biloxi, and Pascagoula, Mississippi, and at Mobile, Alabama, indicate trends of water-surface elevations increasing with time (relative sea-level rise). The trends indicated by the COE data were compared to relative sea-level trends indicated by the National Ocean Survey gages in the Gulf of Mexico. The average global rate of sea level rise has been suggested to approach about 2 mm/yr (0.007 ft/yr). Some leading scientists have suggested rates of sea level rise that are greater than 2 mm/yr, when accounting for effects of greenhouse gas emissions. As the sea level rises and inundates the coastal plain, structures along the existing coast and structures located in the back bays of estuaries will be even more adversely affected by future flooding. Also, if the land surface adjacent to the water also sinks due to soil compaction and other geologic processes (collectively call subsidence), additional land will be inundated. Copyright ASCE 2004.

Rising sea levels will reduce extreme temperature variations in tide-dominated reef habitats.

PubMed

Lowe, Ryan Joseph; Pivan, Xavier; Falter, James; Symonds, Graham; Gruber, Renee

2016-08-01

Temperatures within shallow reefs often differ substantially from those in the surrounding ocean; therefore, predicting future patterns of thermal stresses and bleaching at the scale of reefs depends on accurately predicting reef heat budgets. We present a new framework for quantifying how tidal and solar heating cycles interact with reef morphology to control diurnal temperature extremes within shallow, tidally forced reefs. Using data from northwestern Australia, we construct a heat budget model to investigate how frequency differences between the dominant lunar semidiurnal tide and diurnal solar cycle drive ~15-day modulations in diurnal temperature extremes. The model is extended to show how reefs with tidal amplitudes comparable to their depth, relative to mean sea level, tend to experience the largest temperature extremes globally. As a consequence, we reveal how even a modest sea level rise can substantially reduce temperature extremes within tide-dominated reefs, thereby partially offsetting the local effects of future ocean warming.

Applying downscaled global climate model data to a hydrodynamic surface-water and groundwater model

USGS Publications Warehouse

Swain, Eric; Stefanova, Lydia; Smith, Thomas

2014-01-01

Precipitation data from Global Climate Models have been downscaled to smaller regions. Adapting this downscaled precipitation data to a coupled hydrodynamic surface-water/groundwater model of southern Florida allows an examination of future conditions and their effect on groundwater levels, inundation patterns, surface-water stage and flows, and salinity. The downscaled rainfall data include the 1996-2001 time series from the European Center for Medium-Range Weather Forecasting ERA-40 simulation and both the 1996-1999 and 2038-2057 time series from two global climate models: the Community Climate System Model (CCSM) and the Geophysical Fluid Dynamic Laboratory (GFDL). Synthesized surface-water inflow datasets were developed for the 2038-2057 simulations. The resulting hydrologic simulations, with and without a 30-cm sea-level rise, were compared with each other and field data to analyze a range of projected conditions. Simulations predicted generally higher future stage and groundwater levels and surface-water flows, with sea-level rise inducing higher coastal salinities. A coincident rise in sea level, precipitation and surface-water flows resulted in a narrower inland saline/fresh transition zone. The inland areas were affected more by the rainfall difference than the sea-level rise, and the rainfall differences make little difference in coastal inundation, but a larger difference in coastal salinities.

Comparing the role of absolute sea-level rise and vertical tectonic motions in coastal flooding, Torres Islands (Vanuatu)

PubMed Central

Ballu, Valérie; Bouin, Marie-Noëlle; Siméoni, Patricia; Crawford, Wayne C.; Calmant, Stephane; Boré, Jean-Michel; Kanas, Tony; Pelletier, Bernard

2011-01-01

Since the late 1990s, rising sea levels around the Torres Islands (north Vanuatu, southwest Pacific) have caused strong local and international concern. In 2002–2004, a village was displaced due to increasing sea incursions, and in 2005 a United Nations Environment Programme press release referred to the displaced village as perhaps the world’s first climate change “refugees.” We show here that vertical motions of the Torres Islands themselves dominate the apparent sea-level rise observed on the islands. From 1997 to 2009, the absolute sea level rose by 150 + /-20 mm. But GPS data reveal that the islands subsided by 117 + /-30 mm over the same time period, almost doubling the apparent gradual sea-level rise. Moreover, large earthquakes that occurred just before and after this period caused several hundreds of mm of sudden vertical motion, generating larger apparent sea-level changes than those observed during the entire intervening period. Our results show that vertical ground motions must be accounted for when evaluating sea-level change hazards in active tectonic regions. These data are needed to help communities and governments understand environmental changes and make the best decisions for their future. PMID:21795605

Model projections of rapid sea-level rise on the northeast coast of the United States

NASA Astrophysics Data System (ADS)

Yin, Jianjun; Schlesinger, Michael E.; Stouffer, Ronald J.

2009-04-01

Human-induced climate change could cause global sea-level rise. Through the dynamic adjustment of the sea surface in response to a possible slowdown of the Atlantic meridional overturning circulation, a warming climate could also affect regional sea levels, especially in the North Atlantic region, leading to high vulnerability for low-lying Florida and western Europe. Here we analyse climate projections from a set of state-of-the-art climate models for such regional changes, and find a rapid dynamical rise in sea level on the northeast coast of the United States during the twenty-first century. For New York City, the rise due to ocean circulation changes amounts to 15, 20 and 21cm for scenarios with low, medium and high rates of emissions respectively, at a similar magnitude to expected global thermal expansion. Analysing one of the climate models in detail, we find that a dynamic, regional rise in sea level is induced by a weakening meridional overturning circulation in the Atlantic Ocean, and superimposed on the global mean sea-level rise. We conclude that together, future changes in sea level and ocean circulation will have a greater effect on the heavily populated northeastern United States than estimated previously.

Model Projections of Rapid Sea-Level Rise on the Northeast Coast of the United States

NASA Astrophysics Data System (ADS)

Yin, J.; Schlesinger, M.; Stouffer, R. J.

2009-12-01

Human-induced climate change could cause global sea-level rise. Through the dynamic adjustment of the sea surface in response to a possible slowdown of the Atlantic meridional overturning circulation, a warming climate could also affect regional sea levels, especially in the North Atlantic region, leading to high vulnerability for low-lying Florida and western Europe. In the present study, we analyse climate projections from a set of state-of-the-art climate models for such regional changes, and find a rapid dynamical rise in sea level on the northeast coast of the United States during the twenty-first century. For New York City, the rise due to ocean circulation changes amounts to 15, 20 and 21 cm for scenarios with low, medium and high rates of emissions respectively, at a similar magnitude to expected global thermal expansion. Analysing one of the climate models in detail, we find that a dynamic, regional rise in sea level is induced by a weakening meridional overturning circulation in the Atlantic Ocean, and superimposed on the global mean sea level rise. We conclude that together, future changes in sea level and ocean circulation will have a greater effect on the heavily populated northeastern United States than estimated previously.

Coastal-storm Inundation and Sea-level Rise in New Zealand Scott A. Stephens and Rob Bell

NASA Astrophysics Data System (ADS)

Stephens, S. A.; Bell, R.

2016-12-01

Coastal-storm inundation is a growing problem in New Zealand. It happens occasionally, when the combined forces of weather and sea line up, causing inundation of low-elevation land, coastal erosion, and rivers and stormwater systems to back up causing inland flooding. This becomes a risk where we have placed buildings and infrastructure too close to the coast. Coastal-storm inundation is not a new problem, it has happened historically, but it is becoming more frequent as the sea level continues to rise. From analyses of historic extreme sea-level events, we show how the different sea-level components, such as tide and storm surge, contribute to extreme sea-level and how these components vary around New Zealand. Recent sea-level analyses reveal some large storm surges, bigger than previously reported, and we show the type of weather patterns that drive them, and how this leads to differences in storm surge potential between the east and west coasts. Although large and damaging storm-tides have occurred historically, we show that there is potential for considerably larger elevations to be reached in the "perfect storm", and we estimate the likelihood of such extreme events occurring. Sea-level rise (SLR) will greatly increase the frequency, depth and consequences of coastal-storm inundation in the future. We show an application of a new method to determine the increasing frequency of extreme sea-levels with SLR, one which integrates the extreme tail with regularly-occurring high tides. We present spatial maps of several extreme sea-level threshold exceedance statistics for a case study at Mission Bay, Auckland, New Zealand. The maps show how the local community is likely to face decision points at various SLR thresholds, and we conclude that coastal hazard assessments should ideally use several SLR scenarios and time windows within the next 100 years or more to support the decision-making process for future coastal adaptation and when response options will be needed. In tandem, coastal hazard assessments should also provide information on SLR values linked to expected inundation frequency or depth. This can be linked to plausible timeframes for SLR thresholds to determine when critical decision points for adaptation might be reached, and we show how this might be achieved.

A database of biological and geomorphological sea-level markers from the Last Glacial Maximum to present

PubMed Central

Hibbert, F.D.; Williams, F.H.; Fallon, S.J.; Rohling, E.J.

2018-01-01

The last deglacial was an interval of rapid climate and sea-level change, including the collapse of large continental ice sheets. This database collates carefully assessed sea-level data from peer-reviewed sources for the interval 0 to 25 thousand years ago (ka), from the Last Glacial Maximum to the present interglacial. In addition to facilitating site-specific reconstructions of past sea levels, the database provides a suite of data beyond the range of modern/instrumental variability that may help hone future sea-level projections. The database is global in scope, internally consistent, and contains U-series and radiocarbon dated indicators from both biological and geomorpohological archives. We focus on far-field data (i.e., away from the sites of the former continental ice sheets), but some key intermediate (i.e., from the Caribbean) data are also included. All primary fields (i.e., sample location, elevation, age and context) possess quantified uncertainties, which—in conjunction with available metadata—allows the reconstructed sea levels to be interpreted within both their uncertainties and geological context. PMID:29809175

Salt marsh persistence is threatened by predicted sea-level rise

NASA Astrophysics Data System (ADS)

Crosby, Sarah C.; Sax, Dov F.; Palmer, Megan E.; Booth, Harriet S.; Deegan, Linda A.; Bertness, Mark D.; Leslie, Heather M.

2016-11-01

Salt marshes buffer coastlines and provide critical ecosystem services from storm protection to food provision. Worldwide, these ecosystems are in danger of disappearing if they cannot increase elevation at rates that match sea-level rise. However, the magnitude of loss to be expected is not known. A synthesis of existing records of salt marsh elevation change was conducted in order to consider the likelihood of their future persistence. This analysis indicates that many salt marshes did not keep pace with sea-level rise in the past century and kept pace even less well over the past two decades. Salt marshes experiencing higher local sea-level rise rates were less likely to be keeping pace. These results suggest that sea-level rise will overwhelm most salt marshes' capacity to maintain elevation. Under the most optimistic IPCC emissions pathway, 60% of the salt marshes studied will be gaining elevation at a rate insufficient to keep pace with sea-level rise by 2100. Without mitigation of greenhouse gas emissions this potential loss could exceed 90%, which will have substantial ecological, economic, and human health consequences.

Upper Limit for Regional Sea Level Projections

NASA Astrophysics Data System (ADS)

Jevrejeva, Svetlana; Jackson, Luke; Riva, Riccardo; Grinsted, Aslak; Moore, John

2016-04-01

With more than 150 million people living within 1 m of high tide future sea level rise is one of the most damaging aspects of warming climate. The latest Intergovernmental Panel on Climate Change report (AR5 IPCC) noted that a 0.5 m rise in mean sea level will result in a dramatic increase the frequency of high water extremes - by an order of magnitude, or more in some regions. Thus the flood threat to the rapidly growing urban populations and associated infrastructure in coastal areas are major concerns for society. Hence, impact assessment, risk management, adaptation strategy and long-term decision making in coastal areas depend on projections of mean sea level and crucially its low probability, high impact, upper range. With probabilistic approach we produce regional sea level projections taking into account large uncertainties associated with Greenland and Antarctica ice sheets contribution. We calculate the upper limit (as 95%) for regional sea level projections by 2100 with RCP8.5 scenario, suggesting that for the most coastlines upper limit will exceed the global upper limit of 1.8 m.

White Paper: Summary of the NOAA Workshop - Ecological Effect of Sea Level Rise in the Florida Panhandle and Coastal Alabama: Research and Modeling Needs

EPA Science Inventory

The Center for Sponsored Coastal Ocean Research (CSCOR) is addressing current and future impacts to ecological systems due to the long term effect of sea level rise due to climate change and subsidence on coastal ecosystems through the peer-reviewed research program, the Ecologic...

The potential for sea-level-rise-induced barrier island loss: Insights from the Chandeleur Islands, Louisiana, USA

USGS Publications Warehouse

Moore, Laura J.; Patsch, Kiki; List, Jeffrey H.; Williams, S. Jeffress

2014-01-01

As sea level rises and hurricanes become more intense, barrier islands around the world become increasingly vulnerable to conversion from self-sustaining migrating landforms to submerging or subaqueous sand bodies. To explore the mechanism by which such state changes occur and to assess the factors leading to island disintegration, we develop a suite of numerical simulations for the Chandeleur Islands in Louisiana, U.S.A., which appear to be on the verge of this transition. Our results suggest that the Chandeleurs are likely poised to change state, leading to their demise, within decades depending on future storm history. Contributing factors include high rates of relative sea level rise, limited sediment supply, muddy substrate, current island position relative to former Mississippi River distributary channels, and the effects of changes in island morphology on sediment transport pathways. Although deltaic barrier islands are most sensitive to disintegration because of their muddy substrate, the importance of relative sea level rise rate in determining the timing of threshold crossing suggests that the conceptual models for deltaic barrier island formation and disintegration may apply more broadly in the future.

Adapting to rates versus amounts of climate change: a case of adaptation to sea-level rise

NASA Astrophysics Data System (ADS)

Shayegh, Soheil; Moreno-Cruz, Juan; Caldeira, Ken

2016-10-01

Adaptation is the process of adjusting to climate change in order to moderate harm or exploit beneficial opportunities associated with it. Most adaptation strategies are designed to adjust to a new climate state. However, despite our best efforts to curtail greenhouse gas emissions, climate is likely to continue changing far into the future. Here, we show how considering rates of change affects the projected optimal adaptation strategy. We ground our discussion with an example of optimal investment in the face of continued sea-level rise, presenting a quantitative model that illustrates the interplay among physical and economic factors governing coastal development decisions such as rate of sea-level rise, land slope, discount rate, and depreciation rate. This model shows that the determination of optimal investment strategies depends on taking into account future rates of sea-level rise, as well as social and political constraints. This general approach also applies to the development of improved strategies to adapt to ongoing trends in temperature, precipitation, and other climate variables. Adaptation to some amount of change instead of adaptation to ongoing rates of change may produce inaccurate estimates of damages to the social systems and their ability to respond to external pressures.

The contribution of sea-level rise to flooding in large river catchments

NASA Astrophysics Data System (ADS)

Thiele-Eich, I.; Hopson, T. M.; Gilleland, E.; Lamarque, J.; Hu, A.; Simmer, C.

2012-12-01

Climate change is expected to both impact sea level rise as well as flooding. Our study focuses on the combined effect of climate change on upper catchment precipitation as well as on sea-level rise at the river mouths and the impact this will have on river flooding both at the coast and further upstream. We concentrate on the eight catchments of the Amazonas, Congo, Orinoco, Ganges/Brahmaputra/Meghna, Mississippi, St. Lawrence, Danube and Niger rivers. To assess the impact of climate change, upper catchment precipitation as well as monthly mean thermosteric sea-level rise at the river mouth outflow are taken from the four CCSM4 1° 20th Century ensemble members as well as from six CCSM4 1° ensemble members for the RCP scenarios RCP8.5, 6.0, 4.5 and 2.6. Continuous daily time series for average catchment precipitation and discharge are available for each of the catchments. To arrive at a future discharge time series, we used these observations to develop a simple statistical hydrological model which can be applied to the modelled future upper catchment precipitation values. The analysis of this surrogate discharge time series alone already yields significant changes in flood return levels as well as flood duration. Using the geometry of the river channel, the backwater effect of sea-level rise is incorporated in our analysis of both flood frequencies and magnitudes by calculating the effective additional discharge due to the increase in water level at the river mouth outflow, as well as its tapering impact upstream. By combining these effects, our results focus on the merged impact of changes in extreme precipitation with increases in river height due to sea-level rise at the river mouths. Judging from our preliminary results, the increase in effective discharge due to sea-level rise cannot be neglected when discussing late 21st century flooding in the respective river basins. In particular, we find that especially in countries with low elevation gradient, flood characteristics are impacted by changes in sea-level rise as far inland as 150 kilometers. Therefore, a larger population than the coastal inhabitants alone are exposed to risks of further projected increases of sea-level rise. A prime example for a megacity greatly put at risk by this is Dhaka City in Bangladesh, with a population of roughly 14 million people.

A simple model to estimate the impact of sea-level rise on platform beaches

NASA Astrophysics Data System (ADS)

Taborda, Rui; Ribeiro, Mónica Afonso

2015-04-01

Estimates of future beach evolution in response to sea-level rise are needed to assess coastal vulnerability. A research gap is identified in providing adequate predictive methods to use for platform beaches. This work describes a simple model to evaluate the effects of sea-level rise on platform beaches that relies on the conservation of beach sand volume and assumes an invariant beach profile shape. In closed systems, when compared with the Inundation Model, results show larger retreats; the differences are higher for beaches with wide berms and when the shore platform develops at shallow depths. The application of the proposed model to Cascais (Portugal) beaches, using 21st century sea-level rise scenarios, shows that there will be a significant reduction in beach width.

Earthquakes and sea level - Space and terrestrial metrology on a changing planet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bilham, R.

1991-02-01

A review is presented of the stability and scale of crustal deformation metrology which has particular relevance to monitoring deformation associated with sea level and earthquakes. Developments in space geodesy and crustal deformation metrology in the last two decades have the potential to acquire a homogeneous global data set for monitoring relative horizontal and vertical motions of the earth's surface to within several millimeters. New tools discussed for forecasting sea level rise and damaging earthquakes include: very long baseline interferometry, satellite laser ranging, the principles of GPS geodesy, and new sea level sensors. Space geodesy permits a unified global basismore » for future metrology of the earth, and the continued availability of the GPS is currently fundamental to this unification.« less

Contribution of vertical land motions to coastal sea level variations: a global synthesis of multisatellite altimetry, tide gauge and GPS measurements

NASA Astrophysics Data System (ADS)

Pfeffer, Julia; Allemand, Pascal

2016-04-01

Coastal sea level variations result from a complex mix of climatic, oceanic and geodynamical processes driven by natural and anthropogenic constraints. Combining data from multiple sources is one solution to identify particular processes and progress towards a better understanding of the sea level variations and the assessment of their impacts at coast. Here, we present a global database merging multisatellite altimetry with tide gauges and Global Positioning System (GPS) measurements. Vertical land motions and sea level variations are estimated simultaneously for a network of 886 ground stations with median errors lower than 1 mm/yr. The contribution of vertical land motions to relative sea level variations is explored to better understand the natural hazards associated with sea level rise in coastal areas. Worldwide, vertical land motions dominate 30 % of observed coastal trends. The role of the crust is highly heterogeneous: it can amplify, restrict or counter the effects of climate-induced sea level change. A set of 182 potential vulnerable localities are identified by large coastal subsidence which increases by several times the effects of sea level rise. Though regional behaviours exist, principally caused by GIA (Glacial Isostatic Adjustment), the local variability in vertical land motion prevails. An accurate determination of the vertical motions observed at the coast is fundamental to understand the local processes which contribute to sea level rise, to appraise its impacts on coastal populations and make future predictions.

Studying the impact of climate change on flooding in large river basins

NASA Astrophysics Data System (ADS)

Thiele-Eich, I.; Hopson, T.; Gilleland, E.; Lamarque, J.-F.; Hu, A.; Simmer, C.

2012-04-01

Assessing the potential impact of global climate change on hydrological extremes becomes crucial for regions such as Bangladesh, where a high population density results in a large exposure to risks associated with extreme flooding. In addition, low-lying countries such as Bangladesh are especially vulnerable to sea-level rise and its influence on present-day flood characteristics. By combining the impact of climate change on upper catchment precipitation as well as on sea-level rise at the river mouths, we attempt to analyze the development of flood characteristics such as frequency and magnitude in large river basins. Since flood duration is also of great importance to people exposed to flooding, the development of the number of days with extreme flooding is evaluated for possible trends in the future. Data used includes historical observations from the Global Runoff Data Centre, while recently released model output for upper catchment precipitation and annual mean thermosteric sea-level rise is taken from the four CCSM4 1° 20th Century ensemble members, as well as from six CCSM4 1° ensemble members for the reference concentration pathway scenarios RCP8.5, 6.0, 4.5 and 2.6. A peak-over-threshold approach is used to quantify the expected future changes in flood return levels, where discharge exceedances over a certain threshold are fit to a Generalized Pareto Distribution. Return levels are compared from both 20th century and future model simulations for time slices at 2030, 2050, 2070 and 2090. It can be seen that return periods of flood events decrease as the 21st century progresses in all RCP scenarios, with this shift most pronounced in RCP 8.5. The evaluation of flood duration, or the number of days with discharges above a certain threshold, yields an increase. While the number of days with flooding increases in all RCP scenarios, with the largest increase seen at the end of the 21st century, this increase is only statistically significant for RCP 8.5. Finally, we study how sea-level rise governs the flooding behavior further upstream by calculating the effective additional discharge due to the backwater effect of sea-level rise. Sea-level rise anomalies for the 21st century are taken from CCSM4 model output at each of the river mouths. Judging from our work, the increase in effective discharge due to sea-level rise cannot be neglected when discussing flooding in the respective river basins. Impact of sea-level rise on changes in return levels will be investigated further by using extreme-value theory to calculate how the tails of the current river discharge distribution will be shifted by changing climate.

Assessing hydrological effects of human interventions on coastal systems: numerical applications to the Venice Lagoon

NASA Astrophysics Data System (ADS)

Ferrarin, C.; Ghezzo, M.; Umgiesser, G.; Tagliapietra, D.; Camatti, E.; Zaggia, L.; Sarretta, A.

2012-12-01

The hydrological consequences of historical, contemporary and future human activities on a coastal system were investigated by means of numerical models. The changes in the morphology of the Lagoon of Venice during the last century result from the sedimentological response to the combined effects of human interventions on the environment and global changes. This study focuses on changes from 1927 to 2012 and includes the changes planned for the protection of the city of Venice from storm surges and exceptional tides under future sea level rise scenarios. The application of a hydrodynamic model to simulate the circulation of water masses and the transport of a passive tracer enabled the analysis of the morphodynamic effects on the lagoon circulation and the interaction with the sea. The absolute values of the exchange between the lagoon and sea increased from 1927 to 2002 (from 3900 to 4600 m3 s-1), while the daily fraction of lagoon water volume exchanged decreased. At the same time, the water renewal time shortened from 11.9 to 10.8 days. Morphological changes during the last decade induced an increase of the basin-wide water renewal time (from 10.8 to 11.3 days). In the future, Venice Lagoon will evolve to a more restricted environment due to sea level rise and periodical closure of the lagoon from the sea during flooding events. Simulated scenarios of sea level rise showed that under fall-winter conditions the water renewal time will increased considerably especially in the central part of the lagoon. Furthermore, some considerations on the impact of the hydromorphological changes on the ecological dynamics are proposed.

Hurricane Matthew (2016) and its Storm Surge Inundation under Global Warming Scenarios: Application of an Interactively Coupled Atmosphere-Ocean Model

NASA Astrophysics Data System (ADS)

Jisan, M. A.; Bao, S.; Pietrafesa, L.; Pullen, J.

2017-12-01

An interactively coupled atmosphere-ocean model was used to investigate the impacts of future ocean warming, both at the surface and the layers below, on the track and intensity of a hurricane and its associated storm surge and inundation. The category-5 hurricane Matthew (2016), which made landfall on the South Carolina coast of the United States, was used for the case study. Future ocean temperature changes and sea level rise (SLR) were estimated based on the projection of Inter-Governmental Panel on Climate Change (IPCC)'s Representative Concentration Pathway scenarios RCP 2.6 and RCP 8.5. After being validated with the present-day observational data, the model was applied to simulate the changes in track, intensity, storm surge and inundation that Hurricane Matthew would cause under future climate change scenarios. It was found that a significant increase in hurricane intensity, storm surge water level, and inundation area for Hurricane Matthew under future ocean warming and SLR scenarios. For example, under the RCP 8.5 scenario, the maximum wind speed would increase by 17 knots (14.2%), the minimum sea level pressure would decrease by 26 hPa (2.85%), and the inundated area would increase by 401 km2 (123%). By including the effect of SLR for the middle-21st-century scenario, the inundated area will further increase by up to 49.6%. The increase in the hurricane intensity and the inundated area was also found for the RCP 2.6 scenario. The response of sea surface temperature was analyzed to investigate the change in intensity. A comparison was made between the impacts when only the sea surface warming is considered versus when both the sea surface and the underneath layers are considered. These results showed that even without the effect of SLR, the storm surge level and the inundated area would be higher due to the increased hurricane intensity under the influence of the future warmer ocean temperature. The coupled effect of ocean warming and SLR would cause the hurricane-induced storm surge and inundation to be amplified. The relative importance of the ocean warming versus the SLR was evaluated. Keywords: Hurricane Matthew, Global Warming, Coupled Atmosphere-Ocean Model, Air-Sea interactions, Storm Surge, Inundation

Digital shoreline analysis system-based change detection along the highly eroding Krishna-Godavari delta front

NASA Astrophysics Data System (ADS)

Kallepalli, Akhil; Kakani, Nageswara Rao; James, David B.; Richardson, Mark A.

2017-07-01

Coastal regions are highly vulnerable to rising sea levels due to global warming. Previous Intergovernmental Panel on Climate Change (2013) predictions of 26 to 82 cm global sea level rise are now considered conservative. Subsequent investigations predict much higher levels which would displace 10% of the world's population living less than 10 m above sea level. Remote sensing and GIS technologies form the mainstay of models on coastal retreat and inundation to future sea-level rise. This study estimates the varying trends along the Krishna-Godavari (K-G) delta region. The rate of shoreline shift along the 330-km long K-G delta coast was estimated using satellite images between 1977 and 2008. With reference to a selected baseline from along an inland position, end point rate and net shoreline movement were calculated using a GIS-based digital shoreline analysis system. The results indicated a net loss of about 42.1 km2 area during this 31-year period, which is in agreement with previous literature. Considering the nature of landforms and EPR, the future hazard line (or coastline) is predicted for the area; the predication indicates a net erosion of about 57.6 km2 along the K-G delta coast by 2050 AD.

Effects of Climate Change on Exposure to Coastal Flooding in Latin America and the Caribbean

PubMed Central

Reguero, Borja G.; Losada, Iñigo J.; Díaz-Simal, Pedro; Méndez, Fernando J.; Beck, Michael W.

2015-01-01

This study considers and compares several of the most important factors contributing to coastal flooding in Latin American and the Caribbean (LAC) while accounting for the variations of these factors with location and time. The study assesses the populations, the land areas and the built capital exposed at present and at the middle and end of the 21st century for a set of scenarios that include both climatic and non-climatic drivers. Climatic drivers include global mean sea level, natural modes of climate variability such as El Niño, natural subsidence, and extreme sea levels resulting from the combination of projected local sea-level rise, storm surges and wave setup. Population is the only human-related driver accounted for in the future. Without adaptation, more than 4 million inhabitants will be exposed to flooding from relative sea-level rise by the end of the century, assuming the 8.5 W m−2 trajectory of the Representative Concentration Pathways (RCPs), or RCP8.5. However, the contributions from El Niño events substantially raise the threat in several Pacific-coast countries of the region and sooner than previously anticipated. At the tropical Pacific coastlines, the exposure by the mid-century for an event similar to El Niño 1998 would be comparable to that of the RCP4.5 relative sea-level rise by the end of the century. Furthermore, more than 7.5 million inhabitants, 42,600 km2 and built capital valued at 334 billion USD are currently situated at elevations below the 100-year extreme sea level. With sea levels rising and the population increasing, it is estimated that more than 9 million inhabitants will be exposed by the end of the century for either of the RCPs considered. The spatial distribution of exposure and the comparison of scenarios and timeframes can serve as a guide in future adaptation and risk reduction policies in the region. PMID:26177285

Sea level hazards: Altimetric monitoring of tsunamis and sea level rise

NASA Astrophysics Data System (ADS)

Hamlington, Benjamin Dillon

Whether on the short timescale of an impending tsunami or the much longer timescale of climate change-driven sea level rise, the threat stemming from rising and inundating ocean waters is a great concern to coastal populations. Timely and accurate observations of potentially dangerous changes in sea level are vital in determining the precautionary steps that need to be taken in order to protect coastal communities. While instruments from the past have provided in situ measurements of sea level at specific locations across the globe, satellites can be used to provide improved spatial and temporal sampling of the ocean in addition to producing more accurate measurements. Since 1993, satellite altimetry has provided accurate measurements of sea surface height (SSH) with near-global coverage. Not only have these measurements led to the first definitive estimates of global mean sea level rise, satellite altimetry observations have also been used to detect tsunami waves in the open ocean where wave amplitudes are relatively small, a vital step in providing early warning to those potentially affected by the impending tsunami. The use of satellite altimetry to monitor two specific sea level hazards is examined in this thesis. The first section will focus on the detection of tsunamis in the open ocean for the purpose of providing early warning to coastal inhabitants. The second section will focus on estimating secular trends using satellite altimetry data with the hope of improving our understanding of future sea level change. Results presented here will show the utility of satellite altimetry for sea level monitoring and will lay the foundation for further advancement in the detection of the two sea level hazards considered.

Potential for shoreline changes due to sea-level rise along the U.S. mid-Atlantic region

USGS Publications Warehouse

Gutierrez, Benjamin T.; Williams, S. Jeffress; Thieler, E. Robert

2007-01-01

Sea-level rise over the next century is expected to contribute significantly to physical changes along open-ocean shorelines. Predicting the form and magnitude of coastal changes is important for understanding the impacts to humans and the environment. Presently, the ability to predict coastal changes is limited by the scientific understanding of the many variables and processes involved in coastal change, and the lack of consensus regarding the validity of existing conceptual, analytical, or numerical models. In order to assess potential future coastal changes in the mid-Atlantic U.S. for the U.S. Climate Change Science Program (CCSP), a workshop was convened by the U.S. Geological Survey. Assessments of future coastal change were made by a committee of coastal scientists with extensive professional experience in the mid-Atlantic region. Thirteen scientists convened for a two-day meeting to exchange information and develop a consensus opinion on potential future coastal changes for the mid-Atlantic coast in response to sea-level rise. Using criteria defined in past work, the mid-Atlantic coast was divided into four geomorphic compartments: spits, headlands, wave-dominated barriers, and mixed-energy barriers. A range of potential coastal responses was identified for each compartment based on four sea-level rise scenarios. The four scenarios were based on the assumptions that: a) the long-term sea-level rise rate observed over the 20th century would persist over the 21st century, b) the 20th century rate would increase by 2 mm/yr, c) the 20th century rate would increase by 7 mm/yr, or d) sea-level would rise by 2 m over the next few hundred years. Potential responses to these sea-level rise scenarios depend on the landforms that occur within a region and include increased likelihood for erosion and shoreline retreat for all coastal types, increased likelihood for erosion, overwash and inlet breaching for barrier islands, as well as the possibility of a threshold state (e.g., dramatic change in barrier evolution, such as segmentation or disintegration) for some barrier island systems. The likelihood of the potential coastal responses is expressed using standard terminology employed in climate change assessments (e.g., as used by the Intergovernmental Panel on Climate Change and CCSP). This assessment was based on the coastal geomorphology in its present condition and does not consider any coastal protection that might be undertaken in the future. The committee recognized that a variety of erosion mitigation measures have been implemented along developed portions of the coast and these are very likely to be applied in the future. It was also acknowledged that economics, political will, and other factors can drive decisions to implement these measures, and that such decisions cannot be predicted with confidence. The results of this assessment are depicted graphically on maps of the study area.

Sensitivity of Circulation in the Skagit River Estuary to Sea Level Rise and Future Flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khangaonkar, Tarang; Long, Wen; Sackmann, Brandon

Future climate simulations based on the Intergovernmental Panel on Climate Change emissions scenario (A1B) have shown that the Skagit River flow will be affected, which may lead to modification of the estuarine hydrodynamics. There is considerable uncertainty, however, about the extent and magnitude of resulting change, given accompanying sea level rise and site-specific complexities with multiple interconnected basins. To help quantify the future hydrodynamic response, we developed a three dimensional model of the Skagit River estuary using the Finite Volume Coastal Ocean Model (FVCOM). The model was set up with localized high-resolution grids in Skagit and Padilla Bay sub-basins withinmore » the intermediate-scale FVCOM based model of the Salish Sea (greater Puget Sound and Georgia Basin). Future changes to salinity and annual transport through the basin were examined. The results confirmed the existence of a residual estuarine flow that enters Skagit Bay from Saratoga Passage to the south and exits through Deception Pass. Freshwater from the Skagit River is transported out in the surface layers primarily through Deception Pass and Saratoga Passage, and only a small fraction (≈4%) is transported to Padilla Bay. The moderate future perturbations of A1B emissions, corresponding river flow, and sea level rise of 0.48 m examined here result only in small incremental changes to salinity structure and inter-basin freshwater distribution and transport. An increase in salinity of ~1 ppt in the near-shore environment and a salinity intrusion of approximately 3 km further upstream is predicted in Skagit River, well downstream of the drinking water intakes.« less

Probabilistic reanalysis of twentieth-century sea-level rise.

PubMed

Hay, Carling C; Morrow, Eric; Kopp, Robert E; Mitrovica, Jerry X

2015-01-22

Estimating and accounting for twentieth-century global mean sea level (GMSL) rise is critical to characterizing current and future human-induced sea-level change. Several previous analyses of tide gauge records--employing different methods to accommodate the spatial sparsity and temporal incompleteness of the data and to constrain the geometry of long-term sea-level change--have concluded that GMSL rose over the twentieth century at a mean rate of 1.6 to 1.9 millimetres per year. Efforts to account for this rate by summing estimates of individual contributions from glacier and ice-sheet mass loss, ocean thermal expansion, and changes in land water storage fall significantly short in the period before 1990. The failure to close the budget of GMSL during this period has led to suggestions that several contributions may have been systematically underestimated. However, the extent to which the limitations of tide gauge analyses have affected estimates of the GMSL rate of change is unclear. Here we revisit estimates of twentieth-century GMSL rise using probabilistic techniques and find a rate of GMSL rise from 1901 to 1990 of 1.2 ± 0.2 millimetres per year (90% confidence interval). Based on individual contributions tabulated in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, this estimate closes the twentieth-century sea-level budget. Our analysis, which combines tide gauge records with physics-based and model-derived geometries of the various contributing signals, also indicates that GMSL rose at a rate of 3.0 ± 0.7 millimetres per year between 1993 and 2010, consistent with prior estimates from tide gauge records.The increase in rate relative to the 1901-90 trend is accordingly larger than previously thought; this revision may affect some projections of future sea-level rise.

Sea Level Rise Decision Support Tools for Adaptation Planning in Vulnerable Coastal Communities

NASA Astrophysics Data System (ADS)

Rozum, J. S.; Marcy, D.

2015-12-01

NOAA is involved in a myriad of climate related research and projects that help decision makers and the public understand climate science as well as climate change impacts. The NOAA Office for Coastal Management (OCM) provides data, tools, trainings and technical assistance to coastal resource managers. Beginning in 2011, NOAA OCM began developing a sea level rise and coastal flooding impacts viewer which provides nationally consistent data sets and analyses to help communities with coastal management goals such as: understanding and communicating coastal flood hazards, performing vulnerability assessments and increasing coastal resilience, and prioritizing actions for different inundation/flooding scenarios. The Viewer is available on NOAA's Digital Coast platform: (coast.noaa.gov/ditgitalcoast/tools/slr). In this presentation we will share the lessons learned from our work with coastal decision-makers on the role of coastal flood risk data and tools in helping to shape future land use decisions and policies. We will also focus on a recent effort in California to help users understand the similarities and differences of a growing array of sea level rise decision support tools. NOAA staff and other partners convened a workshop entitled, "Lifting the Fog: Bringing Clarity to Sea Level Rise and Shoreline Change Models and Tools," which was attended by tool develops, science translators and coastal managers with the goal to create a collaborative communication framework to help California coastal decision-makers navigate the range of available sea level rise planning tools, and to inform tool developers of future planning needs. A sea level rise tools comparison matrix will be demonstrated. This matrix was developed as part of this effort and has been expanded to many other states via a partnership with NOAA, Climate Central, and The Nature Conservancy.

Should coastal planners have concern over where land ice is melting?

PubMed Central

Larour, Eric; Ivins, Erik R.; Adhikari, Surendra

2017-01-01

There is a general consensus among Earth scientists that melting of land ice greatly contributes to sea-level rise (SLR) and that future warming will exacerbate the risks posed to human civilization. As land ice is lost to the oceans, both the Earth’s gravitational and rotational potentials are perturbed, resulting in strong spatial patterns in SLR, termed sea-level fingerprints. We lack robust forecasting models for future ice changes, which diminishes our ability to use these fingerprints to accurately predict local sea-level (LSL) changes. We exploit an advanced mathematical property of adjoint systems and determine the exact gradient of sea-level fingerprints with respect to local variations in the ice thickness of all of the world’s ice drainage systems. By exhaustively mapping these fingerprint gradients, we form a new diagnosis tool, henceforth referred to as gradient fingerprint mapping (GFM), that readily allows for improved assessments of future coastal inundation or emergence. We demonstrate that for Antarctica and Greenland, changes in the predictions of inundation at major port cities depend on the location of the drainage system. For example, in London, GFM shows LSL that is significantly affected by changes on the western part of the Greenland Ice Sheet (GrIS), whereas in New York, LSL change predictions are greatly sensitive to changes in the northeastern portions of the GrIS. We apply GFM to 293 major port cities to allow coastal planners to readily calculate LSL change as more reliable predictions of cryospheric mass changes become available. PMID:29152565

Venice: Fifty years after the great flood of November 4, 1966

NASA Astrophysics Data System (ADS)

Rizzoli, P. M.

2017-12-01

Fifty years ago Venice and its lagoon suffered the most devastating flood in their millennial history. The causes of the increasingly recurring floods will be examined, namely the man-induced subsidence in the period 1925-1970 and the storm surges of the Adriatic sea. The engineering solution designed for their protection , named the MOSE system, will be discussed in detail. The MOSE was started in 2003 and is near completion. It consists of four barriers , invisible in normal conditions, which will close the inlets to the lagoon under the prediction of a forthcoming flood. Finally, the perspective of the MOSE capability of protecting the city under scenarios of future global sea level rise will be assessed. This assessment must critically take into account that Venice and its lagoon are confined in the northernmost corner of the semi-enclosed, marginal Mediterranean sea for which the uncertainties of future sea level rise greatly exceed the uncertainties of the global averages.

The multimillennial sea-level commitment of global warming.

PubMed

Levermann, Anders; Clark, Peter U; Marzeion, Ben; Milne, Glenn A; Pollard, David; Radic, Valentina; Robinson, Alexander

2013-08-20

Global mean sea level has been steadily rising over the last century, is projected to increase by the end of this century, and will continue to rise beyond the year 2100 unless the current global mean temperature trend is reversed. Inertia in the climate and global carbon system, however, causes the global mean temperature to decline slowly even after greenhouse gas emissions have ceased, raising the question of how much sea-level commitment is expected for different levels of global mean temperature increase above preindustrial levels. Although sea-level rise over the last century has been dominated by ocean warming and loss of glaciers, the sensitivity suggested from records of past sea levels indicates important contributions should also be expected from the Greenland and Antarctic Ice Sheets. Uncertainties in the paleo-reconstructions, however, necessitate additional strategies to better constrain the sea-level commitment. Here we combine paleo-evidence with simulations from physical models to estimate the future sea-level commitment on a multimillennial time scale and compute associated regional sea-level patterns. Oceanic thermal expansion and the Antarctic Ice Sheet contribute quasi-linearly, with 0.4 m °C(-1) and 1.2 m °C(-1) of warming, respectively. The saturation of the contribution from glaciers is overcompensated by the nonlinear response of the Greenland Ice Sheet. As a consequence we are committed to a sea-level rise of approximately 2.3 m °C(-1) within the next 2,000 y. Considering the lifetime of anthropogenic greenhouse gases, this imposes the need for fundamental adaptation strategies on multicentennial time scales.

The multimillennial sea-level commitment of global warming

PubMed Central

Levermann, Anders; Clark, Peter U.; Marzeion, Ben; Milne, Glenn A.; Pollard, David; Radic, Valentina; Robinson, Alexander

2013-01-01

Global mean sea level has been steadily rising over the last century, is projected to increase by the end of this century, and will continue to rise beyond the year 2100 unless the current global mean temperature trend is reversed. Inertia in the climate and global carbon system, however, causes the global mean temperature to decline slowly even after greenhouse gas emissions have ceased, raising the question of how much sea-level commitment is expected for different levels of global mean temperature increase above preindustrial levels. Although sea-level rise over the last century has been dominated by ocean warming and loss of glaciers, the sensitivity suggested from records of past sea levels indicates important contributions should also be expected from the Greenland and Antarctic Ice Sheets. Uncertainties in the paleo-reconstructions, however, necessitate additional strategies to better constrain the sea-level commitment. Here we combine paleo-evidence with simulations from physical models to estimate the future sea-level commitment on a multimillennial time scale and compute associated regional sea-level patterns. Oceanic thermal expansion and the Antarctic Ice Sheet contribute quasi-linearly, with 0.4 m °C−1 and 1.2 m °C−1 of warming, respectively. The saturation of the contribution from glaciers is overcompensated by the nonlinear response of the Greenland Ice Sheet. As a consequence we are committed to a sea-level rise of approximately 2.3 m °C−1 within the next 2,000 y. Considering the lifetime of anthropogenic greenhouse gases, this imposes the need for fundamental adaptation strategies on multicentennial time scales. PMID:23858443

Using Direct Policy Search to Identify Robust Strategies in Adapting to Uncertain Sea Level Rise and Storm Surge

NASA Astrophysics Data System (ADS)

Garner, G. G.; Keller, K.

2017-12-01

Sea-level rise poses considerable risks to coastal communities, ecosystems, and infrastructure. Decision makers are faced with deeply uncertain sea-level projections when designing a strategy for coastal adaptation. The traditional methods have provided tremendous insight into this decision problem, but are often silent on tradeoffs as well as the effects of tail-area events and of potential future learning. Here we reformulate a simple sea-level rise adaptation model to address these concerns. We show that Direct Policy Search yields improved solution quality, with respect to Pareto-dominance in the objectives, over the traditional approach under uncertain sea-level rise projections and storm surge. Additionally, the new formulation produces high quality solutions with less computational demands than the traditional approach. Our results illustrate the utility of multi-objective adaptive formulations for the example of coastal adaptation, the value of information provided by observations, and point to wider-ranging application in climate change adaptation decision problems.

A Bayesian network to predict vulnerability to sea-level rise: data report

USGS Publications Warehouse

Gutierrez, Benjamin T.; Plant, Nathaniel G.; Thieler, E. Robert

2011-01-01

During the 21st century, sea-level rise is projected to have a wide range of effects on coastal environments, development, and infrastructure. Consequently, there has been an increased focus on developing modeling or other analytical approaches to evaluate potential impacts to inform coastal management. This report provides the data that were used to develop and evaluate the performance of a Bayesian network designed to predict long-term shoreline change due to sea-level rise. The data include local rates of relative sea-level rise, wave height, tide range, geomorphic classification, coastal slope, and shoreline-change rate compiled as part of the U.S. Geological Survey Coastal Vulnerability Index for the U.S. Atlantic coast. In this project, the Bayesian network is used to define relationships among driving forces, geologic constraints, and coastal responses. Using this information, the Bayesian network is used to make probabilistic predictions of shoreline change in response to different future sea-level-rise scenarios.

Sea Level History in 3D: Early results of an ultra-high resolution MCS survey across IODP Expedition 313 drillsites

NASA Astrophysics Data System (ADS)

Mountain, G. S.; Kucuk, H. M.; Nedimovic, M. R.; Austin, J. A., Jr.; Fulthorpe, C.; Newton, A.; Baldwin, K.; Johnson, C.; Stanley, J. N.; Bhatnagar, T.

2015-12-01

Although globally averaged sea level is rising at roughly 3 mm/yr (and is accelerating), rates of local sea-level change measured at coastlines may differ from this number by a factor of two or more; at some locations, sea level may even be falling. This is due to local processes that can match or even reverse the global trend, making it clear that reliable predictions of future impacts of sea-level rise require a firm understanding of processes at the local level. The history of local sea-level change and shoreline response is contained in the geologic record of shallow-water sediments. We report on a continuing study of sea-level history in sediments at the New Jersey continental margin, where compaction and glacial isostatic adjustment are currently adding 2 mm/yr to the globally averaged rise. We collected 570 sq km of ultra-high resolution 3D MCS data aboard the R/V Langseth in June-July 2015; innovative recording and preliminary results are described by Nedimovic et al. in this same session. The goal was to provide regional context to coring and logging at IODP Exp 313 sites 27-29 that were drilled 750 m into the New Jersey shelf in 2009. These sites recovered a nearly continuous record of post-Eocene sediments from non-marine soils, estuaries, shoreface, delta front, pro-delta and open marine settings. Existing seismic data are good but are 2D high-resolution profiles at line spacings too wide to enable mapping of key nearshore features. The Langseth 3D survey used shallow towing of a tuned air gun array to preserve high frequencies, and twenty-four 50-m PCables each 12.5 apart provided 6.25 x 3.125 m common-midpoint bins along seventy-seven 50-km sail lines. With this especially dense spatial resolution of a pre-stack time migrated volume we expect to map rivers, incised valleys, barrier islands, inlets and bays, pro-delta clinoforms, tidal deltas, sequence boundaries, debris flow aprons, and more. Seismic attributes linked to sedimentary facies and geochronology at Exp 313 drill sites will be extended throughout the volume to map the local response to global sea-level change. These analyses will provide an unrivaled opportunity to gauge the local expression of sea-level change for much of the last 40 Ma and lead to informed predictions regarding impacts of a global rise of sea level expected to continue well into the future.

Rapid Settlement of Majuro Atoll, Central Pacific, Following its Emergence 2000 Years Ago

NASA Astrophysics Data System (ADS)

Kayanne, H.; Yamaguchi, T.; Yamano, H.; Yoneda, M.

2010-12-01

Atoll islands are areas of low, flat land, and the sustainability of habitable land in such environments is sensitive to even slight changes in sea level. The rise in sea level projected to occur during this century may lead to the submergence of atoll islands and the widespread loss of habitable land. However, the actual time sequence of past sea level change, island emergence events, and human settlement of newly emerged islands remain poorly constrained. Our excavation survey, combined with calibrated radiocarbon age dates, at Majuro Atoll, Marshall Islands, central Pacific, reveals that emergence of the island, triggered by a fall in sea level, was quickly followed by human settlement. The elevation of the central body of the island exceeded high water level at 2000 years ago, and the complete formation of the island occurred within an interval of 100 years. The island was colonized by people shortly after emergence, at 2000 years ago, prior to the establishment of dense vegetation, and has been continuously settled since that time. Habitable land was created by a fall in sea level, and any future rise in sea level will have a reverse effect, resulting in a loss of habitable land on atoll islands.

Coastal vulnerability assessment of Dry Tortugas National Park (DRTO) to sea-level rise

USGS Publications Warehouse

Pendleton, Elizabeth A.; Thieler, E. Robert; Williams, S. Jeffress

2005-01-01

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Dry Tortugas National Park in Florida. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates, mean tidal range and mean significant wave height. The rankings for each input variable were combined and an index value calculated for 1-minute grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. Dry Tortugas National Park (DRTO) consists of relatively stable to washover-dominated portions of carbonate beach and man-made fortification. The areas within Dry Tortugas that are likely to be most vulnerable to sea-level rise are those with the highest rates of shoreline erosion and the highest wave energy.

Coastal vulnerability assessment of Cape Hatteras National Seashore (CAHA) to sea-level rise

USGS Publications Warehouse

Pendleton, Elizabeth A.; Theiler, E. Robert; Williams, S. Jeffress

2005-01-01

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Cape Hatteras National Seashore (CAHA) in North Carolina. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates, mean tidal range, and mean significant wave height. The rankings for each variable were combined and an index value was calculated for 1-minute grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. Cape Hatteras National Seashore consists of stable and washover dominated segments of barrier beach backed by wetland and marsh. The areas within Cape Hatteras that are likely to be most vulnerable to sea-level rise are those with the highest occurrence of overwash and the highest rates of shoreline change.

Coastal Vulnerability Assessment of Padre Island National Seashore (PAIS) to Sea-Level Rise

USGS Publications Warehouse

Pendleton, Elizabeth A.; Thieler, E. Robert; Williams, S. Jeffress; Beavers, Rebecca S.

2004-01-01

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Padre Island National Seashore in Texas. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, shoreline change rates, mean tidal range and mean significant wave height. The rankings for each variable were combined and an index value calculated for 1-minute grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. Padre Island National Seashore consists of stable to washover dominated portions of barrier beach backed by wetland, marsh, tidal flat, or grassland. The areas within Padre that are likely to be most vulnerable to sea-level rise are those with the highest occurrence of overwash and the highest rates of shoreline change.

Relationship between sea level and climate forcing by CO2 on geological timescales

PubMed Central

Foster, Gavin L.; Rohling, Eelco J.

2013-01-01

On 103- to 106-year timescales, global sea level is determined largely by the volume of ice stored on land, which in turn largely reflects the thermal state of the Earth system. Here we use observations from five well-studied time slices covering the last 40 My to identify a well-defined and clearly sigmoidal relationship between atmospheric CO2 and sea level on geological (near-equilibrium) timescales. This strongly supports the dominant role of CO2 in determining Earth’s climate on these timescales and suggests that other variables that influence long-term global climate (e.g., topography, ocean circulation) play a secondary role. The relationship between CO2 and sea level we describe portrays the “likely” (68% probability) long-term sea-level response after Earth system adjustment over many centuries. Because it appears largely independent of other boundary condition changes, it also may provide useful long-range predictions of future sea level. For instance, with CO2 stabilized at 400–450 ppm (as required for the frequently quoted “acceptable warming” of 2 °C), or even at AD 2011 levels of 392 ppm, we infer a likely (68% confidence) long-term sea-level rise of more than 9 m above the present. Therefore, our results imply that to avoid significantly elevated sea level in the long term, atmospheric CO2 should be reduced to levels similar to those of preindustrial times. PMID:23292932

The Modified Bruun Rule Extended for Landward Transport

DTIC Science & Technology

2013-05-13

has been widely applied by the engineering and scientific communities to interpret shoreline changes and to plan for possible future increases in sea... plan for possible future increases in sea level rise rates. The Bruun Rule assumes that all sand removed from the upper profile is deposited offshore as...transport (e.g., de Beaumont, 1845). Specifically, if a pro- file has an excess of sediment relative to its EBP, and/or the sediment is coarser than

Evidence for a substantial West Antarctic ice sheet contribution to meltwater pulses and abrupt global sea level rise

NASA Astrophysics Data System (ADS)

Fogwill, C. J.; Turney, C. S.; Golledge, N. R.; Etheridge, D. M.; Rubino, M.; Thornton, D.; Woodward, J.; Winter, K.; van Ommen, T. D.; Moy, A. D.; Curran, M. A.; Rootes, C.; Rivera, A.; Millman, H.

2015-12-01

During the last deglaciation (21,000 to 7,000years ago) global sea level rise was punctuated by several abrupt meltwater spikes triggered by the retreat of ice sheets and glaciers world-wide. However, the debate regarding the relative timing, geographical source and the physical mechanisms driving these rapid increases in sea level has catalyzed debate critical to predicting future sea level rise and climate. Here we present a unique record of West Antarctic Ice Sheet elevation change derived from the Patriot Hills blue ice area, located close to the modern day grounding line of the Institute Ice Stream in the Weddell Sea Embayment. Combined isotopic signatures and gas volume analysis from the ice allows us to develop a record of local ice sheet palaeo-altitude that is assessed against independent regional high-resolution ice sheet modeling studies, allowing us to demonstrate that past ice sheet elevations across this sector of the WSE were considerably higher than those suggested by current terrestrial reconstructions. We argue that ice in the WSE had a significant influence on both pre and post LGM sea level rise including MWP-1A (~14.6 ka) and during MWP-1B (11.7-11.6 ka), reconciling past sea level rise and demonstrating for the first time that this sector of the WAIS made a significant and direct contribution to post LGM sea level rise.

Future hurricane storm surge risk for the U.S. gulf and Florida coasts based on projections of thermodynamic potential intensity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balaguru, Karthik; Judi, David R.; Leung, L. Ruby

Coastal populations in the global tropics and sub-tropics are vulnerable to the devastating impacts of hurricane storm surge and this risk is only expected to rise under climate change. In this study, we address this issue for the U.S. Gulf and Florida coasts. Using the framework of Potential Intensity, observations and output from coupled climate models, we show that the future large-scale thermodynamic environment may become more favorable for hurricane intensification. Under the RCP 4.5 emissions scenario and for the peak hurricane season months of August–October, we show that the mean intensities of Atlantic hurricanes may increase by 1.8–4.2 %more » and their lifetime maximum intensities may increase by 2.7–5.3 % when comparing the last two decades of the 20th and 21st centuries. We then combine our estimates of hurricane intensity changes with projections of sea-level rise to understand their relative impacts on future storm surge using simulations with the National Weather Service’s SLOSH (Sea, Lake, and Overland Surges from Hurricanes) model for five historical hurricanes that made landfall in the Gulf of Mexico and Florida. Considering uncertainty in hurricane intensity changes and sea-level rise, our results indicate a median increase in storm surge ranging between 25 and 47 %, with changes in hurricane intensity increasing future storm surge by about 10 % relative to the increase that may result from sea level rise alone, with highly non-linear response of population at risk.« less

Sea-level projections representing the deeply uncertain contribution of the West Antarctic ice sheet.

PubMed

Bakker, Alexander M R; Wong, Tony E; Ruckert, Kelsey L; Keller, Klaus

2017-06-20

There is a growing awareness that uncertainties surrounding future sea-level projections may be much larger than typically perceived. Recently published projections appear widely divergent and highly sensitive to non-trivial model choices . Moreover, the West Antarctic ice sheet (WAIS) may be much less stable than previous believed, enabling a rapid disintegration. Here, we present a set of probabilistic sea-level projections that approximates the deeply uncertain WAIS contributions. The projections aim to inform robust decisions by clarifying the sensitivity to non-trivial or controversial assumptions. We show that the deeply uncertain WAIS contribution can dominate other uncertainties within decades. These deep uncertainties call for the development of robust adaptive strategies. These decision-making needs, in turn, require mission-oriented basic science, for example about potential signposts and the maximum rate of WAIS-induced sea-level changes.

Steric sea level change in the Bay of Bengal: investigating the most variable component of sea level change

NASA Astrophysics Data System (ADS)

Uebbing, Bernd; Kusche, Jürgen; Rietbroek, Roelof; Shum, Ck

2015-04-01

Regional sea level change is influenced by contributions from mass sources, like melting of glaciers and the ice-sheets in Greenland and Antarctica, as well as steric contributions from changes in temperature and salinity of the oceans. Radar altimetry indicates a sea level trend in the Bay of Bengal of about 6 mm- yr over the time period of 2002-2014, which is significantly larger than the global mean trend. Here, we explain 80% of this rise by steric contributions and 20% by mass-related contributions. The increased rise of sea level in the Bay of Bengal threatens the coastal vulnerability of the surrounding countries like Bangladesh, where this effect is exacerbated in combination with land subsidence of the very low lying coastal areas. The BanD-AID (Bangladesh Delta: Assessment of the Causes of Sea-level Rise Hazards and Integrated Development of Predictive Modeling Towards Mitigation and Adaptation) project tries to assess the current and future sea level rise and its impacts on the people living in the threatened coastal areas. As a part of this, it is necessary to analyze the different mass and steric contributors to the total sea level rise to aid in the prediction of future risks. We use data from radar altimetry and the GRACE mission to separate the total sea level rise into contributions from mass sources and steric changes. In our approach, temporal GRACE gravity data and Jason-1 and -2 along track altimetry data are fitted to time invariant spatial patterns (fingerprints) to avoid problems with GRACE resolution, filtering, geocenter and related issues. Our results show that in the Bay of Bengal the steric component is influenced by annual and interannual phenomena and, at the same time, it is significantly larger compared to the individual mass contributions, which show a linear and relatively stable behavior over time. We validate the steric component of our inversion by comparing it to independent steric estimates from 4-D gridded temperature and salinity products from different ARGO processing facilities. We also compare to the classical approach of subtracting the mass component, estimated by GRACE, from the total sea level change, measured by altimetry. Furthermore, we assess the sensitivity of our inversion to the normalized steric fingerprints, which are either based on ARGO fields or derived from ocean modeling. While most steric changes are taking place in the upper 700 m of the ocean, our inversion also allows us to (indirectly) assess the influence from the deep ocean, which is not negligible for the total steric trend.

The Impacts of 3-D Earth Structure on GIA-Induced Crustal Deformation and Future Sea-Level Change in the Antarctic

NASA Astrophysics Data System (ADS)

Powell, E. M.; Hay, C.; Latychev, K.; Gomez, N. A.; Mitrovica, J. X.

2016-12-01

Glacial Isostatic Adjustment (GIA) models used to constrain the extent of past ice sheets and viscoelastic Earth structure, or to correct geodetic and geological observables for ice age effects, generally only consider depth-dependent variations in Earth viscosity and lithospheric structure. A et al. [2013] argued that 3-D Earth structure could impact GIA observables in Antarctica, but concluded that the presence of such structure contributes less to GIA uncertainty than do differences in Antarctic deglaciation histories. New seismic and geological evidence, however, indicates the Antarctic is underlain by complex, high amplitude variability in viscoelastic structure, including a low viscosity zone (LVZ) under West Antarctica. Hay et al. [2016] showed that sea-level fingerprints of modern melting calculated using such Earth models differ from those based on elastic or 1-D viscoelastic Earth models within decades of melting. Our investigation is motivated by two questions: (1) How does 3-D Earth structure, especially this LVZ, impact observations of GIA-induced crustal deformation associated with the last deglaciation? (2) How will 3-D Earth structure affect predictions of future sea-level rise in Antarctica? We compute the gravitationally self-consistent sea level, uplift, and gravity changes using the finite volume treatment of Latychev et al. [2005]. We consider four viscoelastic Earth models: a global 1-D model; a regional, West Antarctic-like 1-D model; a 3-D model where the lithospheric thickness varies laterally; and a 3-D model where both viscosity and lithospheric thickness vary laterally. For our Last Glacial Maximum to present investigations we employ ICE6g [Peltier et al., 2015]. For our present-future investigations we consider a melt scenario consistent with GRACE satellite gravity derived solutions [Harig et al., 2015]. Our calculations indicate that predictions of crustal deformations due to both GIA and ongoing melting are strongly influenced by 3-D lithospheric thickness and viscosity structure. Future sea level change due to ongoing melting is primarily influenced by 3-D viscosity structure. We show that 1-D Earth models built using regional inferences of viscosity and lithospheric thickness do not accurately capture the variability introduced by 3-D Earth structure.

Modeled atoll shoreline and run-up changes in response to sea-level rise and varying large wave conditions at Wake and Midway Atolls, Northwestern Hawaiian Islands

NASA Astrophysics Data System (ADS)

Shope, J. B.; Storlazzi, C. D.; Hoeke, R. K.

2016-12-01

Atoll islands are dynamic features that respond to seasonal alterations in wave conditions and sea level. With sea level and wave climates projected to change over the next century, it is unclear how shoreline wave runup and erosion patterns along these low elevation islands will respond, making it difficult for communities to prepare for the future. To investigate this, extreme boreal winter and summer wave conditions under a variety of future sea-level rise (SLR) scenarios were modeled at two atolls, Wake and Midway, using Delft3D. Nearshore wave conditions were used to find the potential longshore sediment flux, and wave-driven shoreline erosion was calculated as the divergence of the longshore drift; runup and the locations where runup exceed the berm elevation were also found. Of the aforementioned parameters, SLR is projected to be the dominant force driving future island morphological change and flooding. Increased sea level reduces depth-limited breaking by the atoll reef, allowing larger waves to reach the shoreline, increasing runup height and driving greater inland flooding along most coastlines. Previously protected shorelines, such as lagoon shorelines or shorelines with comparably wide reef flats, are projected see the greatest relative increases in runup. Increases in inland flooding extent were greatest along seaward shorelines due to increases in runup. Changes in incident wave directions had a smaller effect on runup, and the projected changes to incident wave heights had a negligible effect. SLR also drove the greatest changes to island shoreline morphology. Windward islands are projected to become thinner as seaward and lagoonal shorelines erode, accreting toward more leeward shorelines and shorelines with comparably wider reef flats. Similarly, leeward islands are anticipated to become thinner and longer, accreting towards their longitudinal ends. The shorelines of these islands will likely change dramatically over the next century as SLR and altered wave climates drive new erosional regimes. It is vital to the sustainability of island communities that the relative magnitudes of these effects are addressed when planning for projected future climates.

The Impacts of 3-D Earth Structure on GIA-Induced Crustal Deformation and Future Sea-Level Change in the Antarctic

NASA Astrophysics Data System (ADS)

Powell, E. M.; Hay, C.; Latychev, K.; Gomez, N. A.; Mitrovica, J. X.

2017-12-01

Glacial Isostatic Adjustment (GIA) models used to constrain the extent of past ice sheets and viscoelastic Earth structure, or to correct geodetic and geological observables for ice age effects, generally only consider depth-dependent variations in Earth viscosity and lithospheric structure. A et al. [2013] argued that 3-D Earth structure could impact GIA observables in Antarctica, but concluded that the presence of such structure contributes less to GIA uncertainty than do differences in Antarctic deglaciation histories. New seismic and geological evidence, however, indicates the Antarctic is underlain by complex, high amplitude variability in viscoelastic structure, including a low viscosity zone (LVZ) under West Antarctica. Hay et al. [2016] showed that sea-level fingerprints of modern melting calculated using such Earth models differ from those based on elastic or 1-D viscoelastic Earth models within decades of melting. Our investigation is motivated by two questions: (1) How does 3-D Earth structure, especially this LVZ, impact observations of GIA-induced crustal deformation associated with the last deglaciation? (2) How will 3-D Earth structure affect predictions of future sea-level rise in Antarctica? We compute the gravitationally self-consistent sea level, uplift, and gravity changes using the finite volume treatment of Latychev et al. [2005]. We consider four viscoelastic Earth models: a global 1-D model; a regional, West Antarctic-like 1-D model; a 3-D model where the lithospheric thickness varies laterally; and a 3-D model where both viscosity and lithospheric thickness vary laterally. For our Last Glacial Maximum to present investigations we employ ICE6g [Peltier et al., 2015]. For our present-future investigations we consider a melt scenario consistent with GRACE satellite gravity derived solutions [Harig et al., 2015]. Our calculations indicate that predictions of crustal deformations due to both GIA and ongoing melting are strongly influenced by 3-D lithospheric thickness and viscosity structure. Future sea level change due to ongoing melting is primarily influenced by 3-D viscosity structure. We show that 1-D Earth models built using regional inferences of viscosity and lithospheric thickness do not accurately capture the variability introduced by 3-D Earth structure.

Transformational Capacity - Exploring a Places Ability to Change

NASA Astrophysics Data System (ADS)

Hirschfeld, D.

2016-12-01

In the face of climate change, there is an emerging consensus that local transformations are necessary in order to avoid the most catastrophic of losses (Burch et al. 2014; Preston et al. 2013). Specifically, it is well known that rising sea levels will lead to increased flooding and habitat loss (McGranahan, et al., 2007). Solutions to sea level rise and its associated impacts will require the active participation of coastal communities who will continue to be relied upon for most of the critical land use and planning decisions (Hurlimann and March 2012). While local governments are needed, these changes are known to be extremely difficult and require a shift to a new development path. Additionally, municipalities need to be able to identify places that can be altered to prepare for sea level rise. Thus we need to enhancer our understanding of transformational capacity. The range of future sea level rise projections are well understood, what is not known is how people will react and change the coastal landscape to address these threats. Additionally, it is not well understood how these different shorezone strategies will in turn impact people. Building on other long-term historical models in coastal engineering, we have developed a framework to generate potential future shorezones in a complex estuarine environment. As shown in Figure 1, the framework includes three general components to determine potential future shorezones. Within each general part of the framework, there are a number of critical data sets used to support this part of the model. For example, the economic piece of the analysis includes, the costs of coastal protective infrastructure and the values of upland parcels. The future shorezones generated through this analysis will be used in sea level rise impacts assessments allowing for a richer conversation in the climate adaptation process. Ultimately, the goals of this presentation are to 1) introduce this specific framework designed to assess the transformational capacity of places 2) use the framework to compare and assess components of the system and 3) show results from research in the San Francisco Bay.

Estimates of twenty-first century sea-level changes for Norway

NASA Astrophysics Data System (ADS)

Simpson, Matthew J. R.; Breili, Kristian; Kierulf, Halfdan P.

2014-03-01

In this work we establish a framework for estimating future regional sea-level changes for Norway. Following recently published works, we consider how different physical processes drive non-uniform sea-level changes by accounting for spatial variations in (1) ocean density and circulation (2) ice and ocean mass changes and associated gravitational effects on sea level and (3) vertical land motion arising from past surface loading change and associated gravitational effects on sea level. An important component of past and present sea-level change in Norway is glacial isostatic adjustment. Central to our study, therefore, is a reassessment of vertical land motion using a far larger set of new observations from a permanent GNSS network. Our twenty-first century sea-level estimates are split into two parts. Firstly, we show regional projections largely based on findings from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4) and dependent on the emission scenarios A2, A1B and B1. These indicate that twenty-first century relative sea-level changes in Norway will vary between -0.2 to 0.3 m (1-sigma ± 0.13 m). Secondly, we explore a high-end scenario, in which a global atmospheric temperature rise of up to 6 °C and emerging collapse for some areas of the Antarctic ice sheets are assumed. Using this approach twenty-first century relative sea-level changes in Norway are found to vary between 0.25 and 0.85 m (min/max ± 0.45 m). We attach no likelihood to any of our projections owing to the lack of understanding of some of the processes that cause sea-level change.

Temporal constraints on future accumulation-area loss of a major Arctic ice cap due to climate change (Vestfonna, Svalbard)

PubMed Central

Möller, Marco; Schneider, Christoph

2015-01-01

Arctic glaciers and ice caps are major contributors to past, present and future sea-level fluctuations. Continued global warming may eventually lead to the equilibrium line altitudes of these ice masses rising above their highest points, triggering unstoppable downwasting. This may feed future sea-level rise considerably. We here present projections for the timing of equilibrium-line loss at the major Arctic ice cap Vestfonna, Svalbard. The projections are based on spatially distributed climatic mass balance modelling driven by the outputs of multiple climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) forced by the Representative Concentration Pathways (RCPs) 2.6, 4.5, 6.0 and 8.5. Results indicate strongly decreasing climatic mass balances over the 21st century for all RCPs considered. Glacier-wide mass-balance rates will drop down to −4 m a−1 w.e. (water equivalent) at a maximum. The date at which the equilibrium line rises above the summit of Vestfonna (630 m above sea level) is calculated to range between 2040 and 2150, depending on scenario. PMID:25628045

Current and Future Urban Stormwater Flooding Scenarios in the Southeast Florida Coasts

NASA Astrophysics Data System (ADS)

Huq, E.; Abdul-Aziz, O. I.

2016-12-01

This study computed rainfall-fed stormwater flooding under the historical and future reference scenarios for the Southeast Coasts Basin of Florida. A large-scale, mechanistic rainfall-runoff model was developed using the U.S. E.P.A. Storm Water Management Model (SWMM 5.1). The model parameterized important processes of urban hydrology, groundwater, and sea level, while including hydroclimatological variables and land use features. The model was calibrated and validated with historical streamflow data. It was then used to estimate the sensitivity of stormwater runoff to the reference changes in hydroclimatological variables (rainfall and evapotranspiration) and different land use/land cover features (imperviousness, roughness). Furthermore, historical (1970-2000) and potential 2050s stormwater budgets were also estimated for the Florida Southeast Coasts Basin by incorporating climatic projections from different GCMs and RCMs, as well as by using relevant projections of sea level and land use/cover. Comparative synthesis of the historical and future scenarios along with the results of sensitivity analysis can aid in efficient management of stormwater flooding for the southeast Florida coasts and similar urban centers under a changing regime of climate, sea level, land use/cover and hydrology.

Greenhouse effect and coastal wetland policy: How Americans could abandon an area the size of Massachusetts at minimum cost

NASA Astrophysics Data System (ADS)

Titus, James G.

1991-01-01

Climatologists generally expect an anthropogenic global warming that could raise sea level 30-150 cm in the next century and more thereafter. One of the impacts would be the loss of coastal wetlands. Although the inundation of adjacent dryland would enable new wetlands to form, much of this land is or will soon be developed. If developed areas are protected, wetlands will be squeezed between an advancing sea and the land being protected, which has already happened in China and the Netherlands, where people have built dikes for centuries. Unlike those countries, the United States has enough land to accommodate the landward migration of wetlands; but governments lack the funds to purchase all the coastal lowlands that might be inundated and the legal authority to prohibit their development. We propose a third approach: allowing property owners to use coastal lowlands today as they choose, but setting up a legal mechanism to ensure that the land is abandoned if and when sea level rises enough to inundate it. Although compensation may be required, this approach would cost less than 1% as much as purchasing the land, and would be (1) economically efficient by enabling real estate markets to incorporate expectations of future sea level rise; (2) constitutional by compensating property owners; and (3) politically feasible by pleasing people who care about the long-term fate of the coastal environment without disturbing people who either are unconcerned about the distant future or do not believe sea level will rise. This article demonstrates that it would be irrational to delay policy formulation until sea level rise projections are more precise. The cost will be small if we act now but great if we wait, and sea level is already rising along most coasts. The US government should develop a strategy in the next three years.

Impact of climate change on New York City's coastal flood hazard: Increasing flood heights from the preindustrial to 2300 CE.

PubMed

Garner, Andra J; Mann, Michael E; Emanuel, Kerry A; Kopp, Robert E; Lin, Ning; Alley, Richard B; Horton, Benjamin P; DeConto, Robert M; Donnelly, Jeffrey P; Pollard, David

2017-11-07

The flood hazard in New York City depends on both storm surges and rising sea levels. We combine modeled storm surges with probabilistic sea-level rise projections to assess future coastal inundation in New York City from the preindustrial era through 2300 CE. The storm surges are derived from large sets of synthetic tropical cyclones, downscaled from RCP8.5 simulations from three CMIP5 models. The sea-level rise projections account for potential partial collapse of the Antarctic ice sheet in assessing future coastal inundation. CMIP5 models indicate that there will be minimal change in storm-surge heights from 2010 to 2100 or 2300, because the predicted strengthening of the strongest storms will be compensated by storm tracks moving offshore at the latitude of New York City. However, projected sea-level rise causes overall flood heights associated with tropical cyclones in New York City in coming centuries to increase greatly compared with preindustrial or modern flood heights. For the various sea-level rise scenarios we consider, the 1-in-500-y flood event increases from 3.4 m above mean tidal level during 1970-2005 to 4.0-5.1 m above mean tidal level by 2080-2100 and ranges from 5.0-15.4 m above mean tidal level by 2280-2300. Further, we find that the return period of a 2.25-m flood has decreased from ∼500 y before 1800 to ∼25 y during 1970-2005 and further decreases to ∼5 y by 2030-2045 in 95% of our simulations. The 2.25-m flood height is permanently exceeded by 2280-2300 for scenarios that include Antarctica's potential partial collapse. Copyright © 2017 the Author(s). Published by PNAS.

Impact of climate change on New York City’s coastal flood hazard: Increasing flood heights from the preindustrial to 2300 CE

PubMed Central

Mann, Michael E.; Emanuel, Kerry A.; Alley, Richard B.; Horton, Benjamin P.; DeConto, Robert M.; Donnelly, Jeffrey P.; Pollard, David

2017-01-01

The flood hazard in New York City depends on both storm surges and rising sea levels. We combine modeled storm surges with probabilistic sea-level rise projections to assess future coastal inundation in New York City from the preindustrial era through 2300 CE. The storm surges are derived from large sets of synthetic tropical cyclones, downscaled from RCP8.5 simulations from three CMIP5 models. The sea-level rise projections account for potential partial collapse of the Antarctic ice sheet in assessing future coastal inundation. CMIP5 models indicate that there will be minimal change in storm-surge heights from 2010 to 2100 or 2300, because the predicted strengthening of the strongest storms will be compensated by storm tracks moving offshore at the latitude of New York City. However, projected sea-level rise causes overall flood heights associated with tropical cyclones in New York City in coming centuries to increase greatly compared with preindustrial or modern flood heights. For the various sea-level rise scenarios we consider, the 1-in-500-y flood event increases from 3.4 m above mean tidal level during 1970–2005 to 4.0–5.1 m above mean tidal level by 2080–2100 and ranges from 5.0–15.4 m above mean tidal level by 2280–2300. Further, we find that the return period of a 2.25-m flood has decreased from ∼500 y before 1800 to ∼25 y during 1970–2005 and further decreases to ∼5 y by 2030–2045 in 95% of our simulations. The 2.25-m flood height is permanently exceeded by 2280–2300 for scenarios that include Antarctica’s potential partial collapse. PMID:29078274

Impact of climate change on New York City's coastal flood hazard: Increasing flood heights from the preindustrial to 2300 CE

NASA Astrophysics Data System (ADS)

Garner, Andra J.; Mann, Michael E.; Emanuel, Kerry A.; Kopp, Robert E.; Lin, Ning; Alley, Richard B.; Horton, Benjamin P.; DeConto, Robert M.; Donnelly, Jeffrey P.; Pollard, David

2017-11-01

The flood hazard in New York City depends on both storm surges and rising sea levels. We combine modeled storm surges with probabilistic sea-level rise projections to assess future coastal inundation in New York City from the preindustrial era through 2300 CE. The storm surges are derived from large sets of synthetic tropical cyclones, downscaled from RCP8.5 simulations from three CMIP5 models. The sea-level rise projections account for potential partial collapse of the Antarctic ice sheet in assessing future coastal inundation. CMIP5 models indicate that there will be minimal change in storm-surge heights from 2010 to 2100 or 2300, because the predicted strengthening of the strongest storms will be compensated by storm tracks moving offshore at the latitude of New York City. However, projected sea-level rise causes overall flood heights associated with tropical cyclones in New York City in coming centuries to increase greatly compared with preindustrial or modern flood heights. For the various sea-level rise scenarios we consider, the 1-in-500-y flood event increases from 3.4 m above mean tidal level during 1970–2005 to 4.0–5.1 m above mean tidal level by 2080–2100 and ranges from 5.0–15.4 m above mean tidal level by 2280–2300. Further, we find that the return period of a 2.25-m flood has decreased from ˜500 y before 1800 to ˜25 y during 1970–2005 and further decreases to ˜5 y by 2030–2045 in 95% of our simulations. The 2.25-m flood height is permanently exceeded by 2280–2300 for scenarios that include Antarctica's potential partial collapse.

Modeling Tidal Wetland Resiliency in the Face of Predicted Accelerated Sea-Level Rise

NASA Astrophysics Data System (ADS)

Schile, L. M.; Callaway, J.; Morris, J. T.; Kelly, M.

2014-12-01

Tidal wetland ecosystems are dynamic coastal habitats that, in California, often occur at the complex nexus of aquatic environments, diked and leveed baylands, and modified upland habitat. Because of their prime location and rich peat soil, many wetlands have been reduced, degraded, and/or destroyed, and yet their important role in carbon sequestration, nutrient and sediment filtering, and as habitat requires us to further examine their sustainability in light of predicted climate change. Predictions of climate change effects for the San Francisco Bay Estuary present a future with reduced summer freshwater input and increased sea levels. We examined the applicability and accuracy of the Marsh Equilibrium Model (MEM), a zero-dimensional model that models organic and inorganic accretion rates under a given rate of sea-level rise. MEM was calibrated using data collected from salt and brackish marshes in the San Francisco Bay Estuary to examine wetland resiliency under a range of sea-level rise and suspended sediment concentration scenarios. At sea-level rise rates 100 cm/century and lower, wetlands remained vegetated. Once sea levels rise above 100 cm, marshes begin to lose ability to maintain elevation, and the presence of adjacent upland habitat becomes increasingly important for marsh migration. The negative effects of sea-level rise on elevations were compounded as suspended sediment concentrations decreased. Results from this study emphasize that the wetland landscape in the bay is threatened with rising sea levels, and there are a limited number of wetlands that will be able to migrate to higher ground as sea levels rise.

Integrating spatial data and shorebird nesting locations to predict the potential future impact of global warming on coastal habitats: A case study on Farasan Islands, Saudi Arabia.

PubMed

Alrashidi, Monif; Shobrak, Mohammed; Al-Eissa, Mohammed S; Székely, Tamás

2012-07-01

One of the expected effects of the global warming is changing coastal habitats by accelerating the rate of sea level rise. Coastal habitats support large number of marine and wetland species including shorebirds (plovers, sandpipers and allies). In this study, we investigate how coastal habitats may be impacted by sea level rise in the Farasan Islands, Kingdom of Saudi Arabia. We use Kentish plover Charadrius alexandrinus - a common coastal breeding shorebird - as an ecological model species to predict the influence of sea level rise. We found that any rise of sea level is likely to inundate 11% of Kentish plover nests. In addition, 5% of the coastal areas of Farasan Islands, which support 26% of Kentish plover nests, will be flooded, if sea level rises by one metre. Our results are constrained by the availability of data on both elevation and bird populations. Therefore, we recommend follow-up studies to model the impacts of sea level rise using different elevation scenarios, and the establishment of a monitoring programme for breeding shorebirds and seabirds in Farasan Islands to assess the impact of climate change on their populations.

Geologic effects and coastal vulnerability to sea-level rise, erosion, and storms

USGS Publications Warehouse

Williams, S.J.; Gutierrez, B.T.; Thieler, E.R.; Pendleton, E.

2008-01-01

A combination of natural and human factors are driving coastal change and making coastal regions and populations increasingly vulnerable. Sea level, a major agent of coastal erosion, has varied greatly from -120 m below present during glacial period low-stands to + 4 to 6 m above present during interglacial warm periods. Geologic and tide gauge data show that global sea level has risen about 12 to 15 cm during the past century with satellite measurements indicating an acceleration since the early 1990s due to thermal expansion and ice-sheet melting. Land subsidence due to tectonic forces and sediment compaction in regions like the mid-Atlantic and Louisiana increase the rate of relative sea-level rise to 40 cm to 100 cm per century. Sea- level rise is predicted to accelerate significantly in the near future due to climate change, resulting in pervasive impacts to coastal regions and putting populations increasingly at risk. The full implications of climate change for coastal systems need to be understood better and long-term plans are needed to manage coasts in order to protect natural resources and mitigate the effects of sea-level rise and increased storms on human infrastructure. 

Birth of the modern Chesapeake Bay estuary between 7.4 and 8.2 ka and implications for global sea-level rise

NASA Astrophysics Data System (ADS)

Bratton, John F.; Colman, Steven M.; Thieler, E. Robert; Seal, Robert R.

2002-12-01

Two major pulses of sea-level rise are thought to have taken place since the last glacial maximum — meltwater pulses (mwp) 1A (12 cal ka) and 1B (9.5 cal ka). Between mwp 1B and about 6 cal ka, many of the complex coastal ecosystems which ring the world's oceans began to form. Here we report data for rhenium, carbon isotopes, total organic carbon, and fossil oysters from Chesapeake Bay which span the transition from fresh to brackish water conditions in the bay in the mid-Holocene. These data constrain sea-level change and resulting environmental change in the bay. They indicate that the transition was rapid, and that it was produced by (1) a third pulse of rapid eustatic sea-level rise, or (2) a geometry of the prehistoric Chesapeake Bay basin which predisposed it to a nonlinear response to a steadily rising sea level. Similar nonlinear changes in vulnerable coastal environments are likely to take place in the future due to polar warming, regardless of the timing or rate of sea-level rise.

Birth of the modern Chesapeake Bay estuary between 7.4 and 8.2 ka and implications for global sea-level rise

USGS Publications Warehouse

Bratton, John F.; Colman, Steven M.; Thieler, E. Robert; Seal, Robert R.

2003-01-01

Two major pulses of sea-level rise are thought to have taken place since the last glacial maximum — meltwater pulses (mwp) 1A (12 cal ka) and 1B (9.5 cal ka). Between mwp 1B and about 6 cal ka, many of the complex coastal ecosystems which ring the world’s oceans began to form. Here we report data for rhenium, carbon isotopes, total organic carbon, and fossil oysters from Chesapeake Bay which span the transition from fresh to brackish water conditions in the bay in the mid-Holocene. These data constrain sea-level change and resulting environmental change in the bay. They indicate that the transition was rapid, and that it was produced by (1) a third pulse of rapid eustatic sea-level rise, or (2) a geometry of the prehistoric Chesapeake Bay basin which predisposed it to a nonlinear response to a steadily rising sea level. Similar nonlinear changes in vulnerable coastal environments are likely to take place in the future due to polar warming, regardless of the timing or rate of sea-level rise.

Winners and losers as mangrove, coral and seagrass ecosystems respond to sea-level rise in Solomon Islands

NASA Astrophysics Data System (ADS)

Albert, Simon; Saunders, Megan I.; Roelfsema, Chris M.; Leon, Javier X.; Johnstone, Elizabeth; Mackenzie, Jock R.; Hoegh-Guldberg, Ove; Grinham, Alistair R.; Phinn, Stuart R.; Duke, Norman C.; Mumby, Peter J.; Kovacs, Eva; Woodroffe, Colin D.

2017-09-01

A 2007 earthquake in the western Solomon Islands resulted in a localised subsidence event in which sea level (relative to the previous coastal settings) rose approximately 30-70 cm, providing insight into impacts of future rapid changes to sea level on coastal ecosystems. Here, we show that increasing sea level by 30-70 cm can have contrasting impacts on mangrove, seagrass and coral reef ecosystems. Coral reef habitats were the clear winners with a steady lateral growth from 2006-2014, yielding a 157% increase in areal coverage over seven years. Mangrove ecosystems, on the other hand, suffered the largest impact through a rapid dieback of 35% (130 ha) of mangrove forest in the study area after subsidence. These forests, however, had partially recovered seven years after the earthquake albeit with a different community structure. The shallow seagrass ecosystems demonstrated the most dynamic response to relative shifts in sea level with both losses and gains in areal extent at small scales of 10-100 m. The results of this study emphasize the importance of considering the impacts of sea-level rise within a complex landscape in which winners and losers may vary over time and space.

Modeling Holocene Barrier Island Morphodynamics and Potential Future Response to Sea- Level Rise, Outer Banks, North Carolina

NASA Astrophysics Data System (ADS)

Moore, L. J.; List, J. H.; Williams, S. J.; Stolper, D.

2006-12-01

A morphological-behavior model, GEOMBEST, which simulates the evolution of coastal morphology and stratigraphy resulting from changes in sea level and sediment supply provides insight into how barriers evolve over time scales ranging from decades to millenia. The model is based upon behavior rules originating from "Bruun rule" concepts, with additional parameters to allow simulation of more complex real-world scenarios. Morphological evolution in the model is driven by disequilibrium between the shoreface and a user-specified theoretical equilibrium profile that maintains its vertical position relative to sea level. As sea level continues rising to an estimated 48 cm above current MSL by AD 2100 (IPCC 2001) and hurricanes of potentially greater intensity impact the coast, barrier islands will respond either by transgressing across underlying strata or by disintegrating and ultimately submerging. Recent studies suggest that some barriers along the U.S. East Coast will break up and become submerged within decades. Other studies show that barriers in Louisiana have already submerged while others are in the process of narrowing in place and submerging. Several factors determine barrier island response to sea-level rise. These include initial topography and morphology of the barrier, underlying geologic framework, availability and supply of sediment, rate of sea-level rise, frequency and intensity of coastal storms, and anthropogenic modifications to the coast. Sensitivity analyses conducted in GEOMBEST suggest that of these factors, barrier-island response is most sensitive to the rate of sea-level rise. The Holocene evolution of the Outer Banks and potential future responses to sea-level rise are explored for a 25-km stretch of coast between Rodanthe and Cape Hatteras, NC using GEOMBEST. An 8500-year hindcast simulation for the study area reproduces closely the morphology and stratigraphy of the modern barrier with approximately 5 x 109 m3 excavated from the Pleistocene substrate, liberating a volume of material sufficient to construct Diamond Shoals. This hindcast simulation serves as the basis for forward simulations of potential future barrier island evolution. A series of model runs based on the low- (0.09 m), mid- (0.48 m) and upper- (0.88 m) range of IPCC (2001) estimates for sea-level rise by the year 2100, suggest the barrier would migrate at rates of approximately 2, 6 and 10 m/yr, respectively. The latter two results would represent an increase over modern long-term erosion rates in the study area, which serve as a proxy for migration rates. Model simulations of barrier response to 4 and 6 m of sea-level rise by AD 2100 (Overpeck et al., 2006), result in model-generated migration rates of 43 and 68 m/yr, respectively. These rates far exceed the highest average long-term barrier island erosion rates observed today along the Louisiana Coast where the Chandeleur Islands disintegrated in response to Hurricane Katrina. If observations in Louisiana can be applied to barrier islands in North Carolina, then we can expect the Outer Banks to become vulnerable to disintegration when migration rates reach approximately 15-20 m/yr. The five forward simulations for the study area suggest rates in this range may be achieved in the Outer Banks if sea-level rise by AD 2100 exceeds IPCC (2001) estimates.

Rising sea levels will reduce extreme temperature variations in tide-dominated reef habitats

PubMed Central

Lowe, Ryan Joseph; Pivan, Xavier; Falter, James; Symonds, Graham; Gruber, Renee

2016-01-01

Temperatures within shallow reefs often differ substantially from those in the surrounding ocean; therefore, predicting future patterns of thermal stresses and bleaching at the scale of reefs depends on accurately predicting reef heat budgets. We present a new framework for quantifying how tidal and solar heating cycles interact with reef morphology to control diurnal temperature extremes within shallow, tidally forced reefs. Using data from northwestern Australia, we construct a heat budget model to investigate how frequency differences between the dominant lunar semidiurnal tide and diurnal solar cycle drive ~15-day modulations in diurnal temperature extremes. The model is extended to show how reefs with tidal amplitudes comparable to their depth, relative to mean sea level, tend to experience the largest temperature extremes globally. As a consequence, we reveal how even a modest sea level rise can substantially reduce temperature extremes within tide-dominated reefs, thereby partially offsetting the local effects of future ocean warming. PMID:27540589

Grain-size based sea-level reconstruction in the south Bohai Sea during the past 135 kyr

NASA Astrophysics Data System (ADS)

Yi, Liang; Chen, Yanping

2013-04-01

Future anthropogenic sea-level rise and its impact on coastal regions is an important issue facing human civilizations. Due to the short nature of the instrumental record of sea-level change, development of proxies for sea-level change prior to the advent of instrumental records is essential to reconstruct long-term background sea-level changes on local, regional and global scales. Two of the most widely used approaches for past sea-level changes are: (1) exploitation of dated geomorphologic features such as coastal sands (e.g. Mauz and Hassler, 2000), salt marsh (e.g. Madsen et al., 2007), terraces (e.g. Chappell et al., 1996), and other coastal sediments (e.g. Zong et al., 2003); and (2) sea-level transfer functions based on faunal assemblages such as testate amoebae (e.g. Charman et al., 2002), foraminifera (e.g. Chappell and Shackleton, 1986; Horton, 1997), and diatoms (e.g. Horton et al., 2006). While a variety of methods has been developed to reconstruct palaeo-changes in sea level, many regions, including the Bohai Sea, China, still lack detailed relative sea-level curves extending back to the Pleistocene (Yi et al., 2012). For example, coral terraces are absent in the Bohai Sea, and the poor preservation of faunal assemblages makes development of a transfer function for a relative sea-level reconstruction unfeasible. In contrast, frequent alternations between transgression and regression has presumably imprinted sea-level change on the grain size distribution of Bohai Sea sediments, which varies from medium silt to coarse sand during the late Quaternary (IOCAS, 1985). Advantages of grainsize-based relative sea-level transfer function approaches are that they require smaller sample sizes, allowing for replication, faster measurement and higher spatial or temporal resolution at a fraction of the cost of detail micro-palaeontological analysis (Yi et al., 2012). Here, we employ numerical methods to partition sediment grain size using a combined database of marine surface and core samples, and to quantitatively reconstruct sea-level variation since the late Pleistocene in the south Bohai Sea, China. New insights into regional relative sea-level changes since the late Pleistocene are obtained (Yi et al., 2012): (1) The grain size of surface and core samples can be mathematically partitioned using the Weibull distribution into four components. These four components with differing modal sizes and percentages could be interpreted as a long-term suspension component, which only settles under low turbulence conditions, sortable silt and very fine sand components transported by suspension during greater turbulence and bedload transport component, respectively. (2) Through regression and rigorous verification techniques, the reference water level could be reconstructed from sediment grain size. The reconstruction quantitatively extends the regional relative sea-level history to the late Pleistocene, providing a comparatively long dataset to evaluate regional sea-level variability. (3) We find no evidence of a sea-level high stand during MIS3 but rather a substantial regression during 70-30 cal kyr BP and potentially exposed land during 38-20 cal kyr BP. These results for the south Bohai Sea are in good agreement with published global sea-level records for the late Pleistocene, implying similarities between local and global sea-level patterns. Therefore, it is concluded that grain-size based sea-level reconstruction provide results that are comparable to other reconstruction methods and demonstrates great potential application for future works. (The data was shared on http://hurricane.ncdc.noaa.gov/) References Chappell, J., Omura, A., Esat, T., McCulloch, M., Pandolfi, J., Ota, Y., Pillans, B., 1996. Reconciliation of late Quaternary sea levels derived from coral terraces at Huon Peninsula with deep sea oxygen isotope records. Earth and Planetary Science Letters 141, 227-236. Chappell, J., Shackleton, N.J., 1986. Oxygen isotopes and sea level. Nature 324, 137-140. Charman, D.J., Roe, H.M., Roland Gehrels, W., 2002. Modern distribution of saltmarsh testate amoebae: regional variability of zonation and response to environmental variables. Journal of Quaternary Science 17, 387-409. Horton, B.P., 1997. Quantification of the indicative meaning of a range of Holocene sea-level index points from the western North Sea, Department of Geography. University of Durham, Durham City, UK, p. 509. Horton, B.P., Corbett, R., Culver, S.J., Edwards, R.J., Hillier, C., 2006. Modern saltmarsh diatom distributions of the Outer Banks, North Carolina, and the development of a transfer function for high resolution reconstructions of sea level. Estuarine, Coastal and Shelf Science 69, 381-394. IOCAS (Institute of Oceanology, Chinese Academy of Sciences), 1985. Bohai Sea Geology. Science Press, Beijing, China. Madsen, A.T., Murray, A.S., Andersen, T.J., Pejrup, M., 2007. Temporal changes of accretion rates on an estuarine salt marsh during the late Holocene -Reflection of local sea level changes? The Wadden Sea, Denmark. Marine Geology 242, 221-233. Mauz, B., Hassler, U., 2000. Luminescence chronology of Late Pleistocene raised beaches in southern Italy: new data of relative sea-level changes. Marine Geology 170, 187-203. Yi, L., Yu, H.J., Ortiz, J.D., Xu, X.Y., Qiang, X.K., Huang, H.J., Shi, X., Deng, C.L., 2012. A reconstruction of late Pleistocene relative sea level in the south Bohai Sea, China, based on sediment grain-size analysis. Sedimentary Geology 281, 88-100. Zong, Y., Shennan, I., Combellick, R.A., Hamilton, S.L., Rutherford, M.M., 2003. Microfossil evidence for land movements associated with the AD 1964 Alaska earthquake. The Holocene 13, 7-20.

Sea Level Rise Impacts On Infrastructure Vulnerability

NASA Astrophysics Data System (ADS)

Pasqualini, D.; Mccown, A. W.; Backhaus, S.; Urban, N. M.

2015-12-01

Increase of global sea level is one of the potential consequences of climate change and represents a threat for the U.S.A coastal regions, which are highly populated and home of critical infrastructures. The potential danger caused by sea level rise may escalate if sea level rise is coupled with an increase in frequency and intensity of storms that may strike these regions. These coupled threats present a clear risk to population and critical infrastructure and are concerns for Federal, State, and particularly local response and recovery planners. Understanding the effect of sea level rise on the risk to critical infrastructure is crucial for long planning and for mitigating potential damages. In this work we quantify how infrastructure vulnerability to a range of storms changes due to an increase of sea level. Our study focuses on the Norfolk area of the U.S.A. We assess the direct damage of drinking water and wastewater facilities and the power sector caused by a distribution of synthetic hurricanes. In addition, our analysis estimates indirect consequences of these damages on population and economic activities accounting also for interdependencies across infrastructures. While projections unanimously indicate an increase in the rate of sea level rise, the scientific community does not agree on the size of this rate. Our risk assessment accounts for this uncertainty simulating a distribution of sea level rise for a specific climate scenario. Using our impact assessment results and assuming an increase of future hurricanes frequencies and intensities, we also estimate the expected benefits for critical infrastructure.

Evaluation of Dynamic Coastal Response to Sea-level Rise Modifies Inundation Likelihood

NASA Technical Reports Server (NTRS)

Lentz, Erika E.; Thieler, E. Robert; Plant, Nathaniel G.; Stippa, Sawyer R.; Horton, Radley M.; Gesch, Dean B.

2016-01-01

Sea-level rise (SLR) poses a range of threats to natural and built environments, making assessments of SLR-induced hazards essential for informed decision making. We develop a probabilistic model that evaluates the likelihood that an area will inundate (flood) or dynamically respond (adapt) to SLR. The broad-area applicability of the approach is demonstrated by producing 30x30m resolution predictions for more than 38,000 sq km of diverse coastal landscape in the northeastern United States. Probabilistic SLR projections, coastal elevation and vertical land movement are used to estimate likely future inundation levels. Then, conditioned on future inundation levels and the current land-cover type, we evaluate the likelihood of dynamic response versus inundation. We find that nearly 70% of this coastal landscape has some capacity to respond dynamically to SLR, and we show that inundation models over-predict land likely to submerge. This approach is well suited to guiding coastal resource management decisions that weigh future SLR impacts and uncertainty against ecological targets and economic constraints.

Reconstructing Mid- to Late Holocene sea-level change from coral microatolls, French Polynesia

NASA Astrophysics Data System (ADS)

Hallmann, Nadine; Camoin, Gilbert; Eisenhauer, Anton; Botella, Alberic; Milne, Glenn; Vella, Claude; Samankassou, Elias; Pothin, Virginie; Dussouillez, Philippe; Fleury, Jules; Fietzke, Jan

2017-04-01

Coral microatolls are sensitive low-tide recorders, as their vertical accretion is limited by the mean low water springs level, and can be considered therefore as high-precision recorders of sea-level change. They are of pivotal importance to resolving the rates and amplitudes of millennial-to-century scale changes during periods of relative climate stability such as the Mid- to Late Holocene, which serves as an important baseline of natural variability prior to the industrial revolution. It provides therefore a unique opportunity to study coastal response to sea-level rise, even if the rates of sea-level rise during the Mid- to Late Holocene were lower than the current rates and those expected in the near future. Mid- to Late Holocene relative sea-level change in French Polynesia was reconstructed based on the coupling between absolute U/Th dating of in situ coral microatolls and their precise positioning via GPS RTK (Real Time Kinematic) measurements. The twelve studied islands represent ideal settings for accurate sea-level studies because: 1) they can be regarded as tectonically stable during the relevant period (slow subsidence), 2) they are located far from former ice sheets (far-field), 3) they are characterized by a low tidal amplitude, and 4) they cover a wide range of latitudes which produces significantly improved constraints on GIA (Glacial Isostatic Adjustment) model parameters. A step-like sea-level rise is evidenced between 6 and 3.9 ka leading to a short sea-level highstand of about a meter in amplitude between 3.9 and 3.6 ka. A sea-level fall, at an average rate of 0.3 mm.yr-1, is recorded between 3.6 and 1.2 ka when sea level approached its present position. In addition, growth pattern analysis of coral microatolls allows the reconstruction of low-amplitude, high-frequency sea-level change on centennial to sub-decadal time scales. The reconstructed sea-level curve extends the Tahiti last deglacial sea-level curve [Deschamps et al., 2012, Nature, 483, 559-564], and is in good agreement with a geophysical model tuned to fit far-field deglacial records [Bassett et al., 2005, Science, 309, 925-928].

An Assessment of IPCC 20th Century Climate Simulations Using the 15-year Sea Level Record from Altimetry

NASA Astrophysics Data System (ADS)

Leuliette, E.; Nerem, S.; Jakub, T.

2006-07-01

Recen tly, multiple ensemble climate simulations h ave been produced for th e forthco ming Fourth A ssessment Report of the Intergovernmental Panel on Climate Change (IPCC). N early two dozen coupled ocean- atmo sphere models have contr ibuted output for a variety of climate scen arios. One scenar io, the climate of the 20th century exper imen t (20C3 M), produces model output that can be comp ared to th e long record of sea level provided by altimetry . Generally , the output from the 20C3M runs is used to initialize simulations of future climate scenar ios. Hence, v alidation of the 20 C3 M experiment resu lts is crucial to the goals of th e IPCC. We present compar isons of global mean sea level (G MSL) , global mean steric sea level change, and regional patterns of sea lev el chang e from these models to r esults from altimetry, tide gauge measurements, and reconstructions.

The future for the Global Sea Level Observing System (GLOSS) Sea Level Data Rescue

NASA Astrophysics Data System (ADS)

Bradshaw, Elizabeth; Matthews, Andrew; Rickards, Lesley; Aarup, Thorkild

2016-04-01

Historical sea level data are rare and unrepeatable measurements with a number of applications in climate studies (sea level rise), oceanography (ocean currents, tides, surges), geodesy (national datum), geophysics and geology (coastal land movements) and other disciplines. However, long-term time series are concentrated in the northern hemisphere and there are no records at the Permanent Service for Mean Sea Level (PSMSL) global data bank longer than 100 years in the Arctic, Africa, South America or Antarctica. Data archaeology activities will help fill in the gaps in the global dataset and improve global sea level reconstruction. The Global Sea Level Observing System (GLOSS) is an international programme conducted under the auspices of the WMO-IOC Joint Technical Commission for Oceanography and Marine Meteorology. It was set up in 1985 to collect long-term tide gauge observations and to develop systems and standards "for ocean monitoring and flood warning purposes". At the GLOSS-GE-XIV Meeting in 2015, GLOSS agreed on a number of action items to be developed in the next two years. These were: 1. To explore mareogram digitisation applications, including NUNIEAU (more information available at: http://www.mediterranee.cerema.fr/logiciel-de-numerisation-des-enregistrements-r57.html) and other recent developments in scanning/digitisation software, such as IEDRO's Weather Wizards program, to see if they could be used via a browser. 2. To publicise sea level data archaeology and rescue by: • maintaining and regularly updating the Sea Level Data Archaeology page on the GLOSS website • strengthening links to the GLOSS data centres and data rescue organisations e.g. linking to IEDRO, ACRE, RDA • restarting the sea level data rescue blog with monthly posts. 3. Investigate sources of funding for data archaeology and rescue projects. 4. Propose "Guidelines" for rescuing sea level data. These action items will aid the discovery, scanning, digitising and quality control of analogue tide gauge charts and sea level ledgers and improve the quality, quantity and availability of long-term sea level data series.

Ecosystem Structure Changes in the Turkish Seas as a Response to Overfishing

NASA Astrophysics Data System (ADS)

Gazihan Akoglu, Ayse; Salihoglu, Baris; Akoglu, Ekin; Kideys, Ahmet E.

2013-04-01

Human population in Turkey has grown more than five-fold since its establishment in 1923 and more than 73 million people are currently living in the country. Turkey is surrounded by partially connected seas (the Black Sea, the Sea of Marmara, the Aegean Sea and the Mediterranean Sea) each of which has significantly different productivity levels and ecosystem characteristics. Increasing human population with its growing socio-economic needs has generated an intensive fishing pressure on the fish stocks in its exclusive economic zone. Fishing grounds in the surrounding seas were exploited with different fishing intensities depending upon their productivity level and catch rates. Hence, the responses of these different ecosystems to overfishing have been realized differently. In this study, changes of the ecosystem structures in the Turkish Seas were comparatively investigated by ecosystem indices such as Marine Trophic Index (MTI), Fishing in Balance (FiB) and Primary Production Required (PPR) to assess the degree of sustainability of the fish stocks for future generations.

Understanding extreme sea levels for broad-scale coastal impact and adaptation analysis

NASA Astrophysics Data System (ADS)

Wahl, T.; Haigh, I. D.; Nicholls, R. J.; Arns, A.; Dangendorf, S.; Hinkel, J.; Slangen, A. B. A.

2017-07-01

One of the main consequences of mean sea level rise (SLR) on human settlements is an increase in flood risk due to an increase in the intensity and frequency of extreme sea levels (ESL). While substantial research efforts are directed towards quantifying projections and uncertainties of future global and regional SLR, corresponding uncertainties in contemporary ESL have not been assessed and projections are limited. Here we quantify, for the first time at global scale, the uncertainties in present-day ESL estimates, which have by default been ignored in broad-scale sea-level rise impact assessments to date. ESL uncertainties exceed those from global SLR projections and, assuming that we meet the Paris agreement goals, the projected SLR itself by the end of the century in many regions. Both uncertainties in SLR projections and ESL estimates need to be understood and combined to fully assess potential impacts and adaptation needs.

Water storage in marine sediment and implications for inferences of past global ice volume

NASA Astrophysics Data System (ADS)

Ferrier, K.; Li, Q.; Pico, T.; Austermann, J.

2017-12-01

Changes in past sea level are of wide interest because they provide information on the sensitivity of ice sheets to climate change, and thus inform predictions of future sea-level change. Sea level changes are influenced by many processes, including the storage of water in sedimentary pore space. Here we use a recent extension of gravitationally self-consistent sea-level models to explore the effects of marine sedimentary water storage on the global seawater balance and inferences of past global ice volume. Our analysis suggests that sedimentary water storage can be a significant component of the global seawater budget over the 105-year timescales associated with glacial-interglacial cycles, and an even larger component over longer timescales. Estimates of global sediment fluxes to the oceans suggest that neglecting marine sedimentary water storage may produce meter-scale errors in estimates of peak global mean sea level equivalent (GMSL) during the Last Interglacial (LIG). These calculations show that marine sedimentary water storage can be a significant contributor to the overall effects of sediment redistribution on sea-level change, and that neglecting sedimentary water storage can lead to substantial errors in inferences of global ice volume at past interglacials. This highlights the importance of accounting for the influences of sediment fluxes and sedimentary water storage on sea-level change over glacial-interglacial timescales.

Last Deglacial Sea Level: A Curated Database of Indicators of Past Sea Levels from Biological and Geomorphological Archives

NASA Astrophysics Data System (ADS)

Hibbert, F. D.; Williams, F. H.; Fallon, S.; Rohling, E. J.

2017-12-01

The last deglacial was an interval of rapid climate and sea-level change, including the collapse of large continental ice sheets. This database collates carefully assessed sea-level data from peer-reviewed sources for the interval 0 to 25 thousand years ago (ka), from the last glacial maximum to the present interglacial conditions. In addition to facilitating site-specific reconstructions of past sea levels, the database provides a suite of data beyond the range of modern/instrumental variability that may help hone future sea-level projections. The database is global in scope, internally consistent, and contains U-series and radiocarbon dated indicators from both biological and geomorpohological archives. We focus on far-field data (i.e., away from the sites of the former continental ice sheets), but some key intermediate (i.e., from the Caribbean) data are also included. All primary fields (i.e., sample location, elevation, age and context) possess quantified uncertainties, which - in conjunction with available metadata - allows the reconstructed sea levels to be interpreted within both their uncertainties and geological context. Consistent treatment of each of the individual records in the database, and incorporation of fully expressed uncertainties, allows datasets to be easily compared. The compilation contains 145 studies from 40 locations (>2,000 data points) and includes all raw information and metadata.

Contamination of the cement raw material in a quarry site by seawater intrusion, Darica-Turkey

NASA Astrophysics Data System (ADS)

Camur, M. Zeki; Doyuran, Vedat

2008-02-01

The open pit mining nearby shoreline is planned to be extended into below sea level in order to use additional reserves of the cement raw material (marl). The raw material is currently contaminated by seawater intrusion below a depth of 20 m up to the distance of 90 m from shoreline. Seawater intrusion related contamination of the material used for the cement production was investigated by means of diffusion process for the future two below sea level mining scenarios covering 43 years of period. According to the results, chloride concentrations higher than the tolerable limit of a cement raw material would be present in the material about 10-25 cm inward from each discontinuity surface, controlling groundwater flow, located between 170 and 300 m landward from the shoreline at below sea level mining depths of 0-30 m. The estimations suggest that total amounts of dilution required for the contaminated raw material to reduce its concentration level to the tolerance limit with uncontaminated raw material are about 113- to 124-fold for scenario I (13 years of below sea level mining after 30 years of above sea level mining) and about 126- to 138-fold for scenario II (43 years of simultaneous above and below sea level minings).

Possible impacts of sea level rise on disease transmission and potential adaptation strategies, a review.

PubMed

Dvorak, Ana C; Solo-Gabriele, Helena M; Galletti, Andrea; Benzecry, Bernardo; Malone, Hannah; Boguszewski, Vicki; Bird, Jason

2018-07-01

Sea levels are projected to rise in response to climate change, causing the intrusion of sea water into land. In flat coastal regions, this would generate an increase in shallow water covered areas with limited circulation. This scenario raises a concern about the consequences it could have on human health, specifically the possible impacts on disease transmission. In this review paper we identified three categories of diseases which are associated with water and whose transmission can be affected by sea level rise. These categories include: mosquitoborne diseases, naturalized organisms (Vibrio spp. and toxic algae), and fecal-oral diseases. For each disease category, we propose comprehensive adaptation strategies that would help minimize possible health risks. Finally, the City of Key West, Florida is analyzed as a case study, due to its inherent vulnerability to sea level rise. Current and projected adaptation techniques are discussed as well as the integration of additional recommendations, focused on disease transmission control. Given that sea level rise will likely continue into the future, the promotion and implementation of positive adaptation strategies is necessary to ensure community resilience. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Science-Policy Link: Stakeholder Reactions to the Uncertainties of Future Sea Level Rise

NASA Astrophysics Data System (ADS)

Plag, H.; Bye, B.

2011-12-01

Policy makers and stakeholders in the coastal zone are equally challenged by the risk of an anticipated rise of coastal Local Sea Level (LSL) as a consequence of future global warming. Many low-lying and often densely populated coastal areas are under risk of increased inundation. More than 40% of the global population is living in or near the coastal zone and this fraction is steadily increasing. A rise in LSL will increase the vulnerability of coastal infrastructure and population dramatically, with potentially devastating consequences for the global economy, society, and environment. Policy makers are faced with a trade-off between imposing today the often very high costs of coastal protection and adaptation upon national economies and leaving the costs of potential major disasters to future generations. They are in need of actionable information that provides guidance for the development of coastal zones resilient to future sea level changes. Part of this actionable information comes from risk and vulnerability assessments, which require information on future LSL changes as input. In most cases, a deterministic approach has been applied based on predictions of the plausible range of future LSL trajectories as input. However, there is little consensus in the scientific community on how these trajectories should be determined, and what the boundaries of the plausible range are. Over the last few years, many publications in Science, Nature and other peer-reviewed scientific journals have revealed a broad range of possible futures and significant epistemic uncertainties and gaps concerning LSL changes. Based on the somewhat diffuse science input, policy and decision makers have made rather different choices for mitigation and adaptation in cases such as Venice, The Netherlands, New York City, and the San Francisco Bay area. Replacing the deterministic, prediction-based approach with a statistical one that fully accounts for the uncertainties and epistemic gaps would provide a different kind of science input to policy makers and stakeholders. Like in many other insurance problems (for example, earthquakes), where deterministic predictions are not possible and decisions have to be made on the basis of statistics and probabilities, the statistical approach to coastal resilience would require stakeholders to make decisions on the basis of probabilities instead of predictions. The science input for informed decisions on adaptation would consist of general probabilities of decadal to century scale sea level changes derived from paleo records, including the probabilities for large and rapid rises. Similar to other problems where the appearance of a hazard is associated with a high risk (like a fire in a house), this approach would also require a monitoring and warning system (a "smoke detector") capable of detecting any onset of a rapid sea level rise.

A preliminary evaluation of nearhore extreme sea level and wave models for fringing reef environments

NASA Astrophysics Data System (ADS)

Hoeke, R. K.; Reyns, J.; O'Grady, J.; Becker, J. M.; Merrifield, M. A.; Roelvink, J. A.

2016-02-01

Oceanic islands are widely perceived as vulnerable to sea level rise and are characterized by steep nearshore topography and fringing reefs. In such settings, near shore dynamics and (non-tidal) water level variability tends to be dominated by wind-wave processes. These processes are highly sensitive to reef morphology and roughness and to regional wave climate. Thus sea level extremes tend to be highly localized and their likelihood can be expected to change in the future (beyond simple extrapolation of sea level rise scenarios): e.g. sea level rise may increase the effective mean depth of reef crests and flats and ocean acidification and/or increased temperatures may lead to changes in reef structure. The problem is sufficiently complex that analytic or numerical approaches are necessary to estimate current hazards and explore potential future changes. In this study, we evaluate the capacity of several analytic/empirical approaches and phase-averaged and phase-resolved numerical models at sites in the insular tropical Pacific. We consider their ability to predict time-averaged wave setup and instantaneous water level exceedance probability (or dynamic wave run-up) as well as computational cost; where possible, we compare the model results with in situ observations from a number of previous studies. Preliminary results indicate analytic approaches are by far the most computationally efficient, but tend to perform poorly when alongshore straight and parallel morphology cannot be assumed. Phase-averaged models tend to perform well with respect to wave setup in such situations, but are unable to predict processes related to individual waves or wave groups, such as infragravity motions or wave run-up. Phase-resolved models tend to perform best, but come at high computational cost, an important consideration when exploring possible future scenarios. A new approach of combining an unstructured computational grid with a quasi-phase averaged approach (i.e. only phase resolving motions below a frequency cutoff) shows promise as a good compromise between computational efficiency and resolving processes such as wave runup and overtopping in more complex bathymetric situations.

Contributions of internal climate variability to mitigation of projected future regional sea level rise

NASA Astrophysics Data System (ADS)

Hu, A.; Bates, S. C.

2017-12-01

Observations indicate that the global mean surface temperature is rising, so does the global mean sea level. Sea level rise (SLR) can impose significant impacts on island and coastal communities, especially when SLR is compounded with storm surges. Here, via analyzing results from two sets of ensemble simulations from the Community Earth System Model version 1, we investigate how the potential SLR benefits through mitigating the future emission scenarios from business as usual to a mild-mitigation over the 21st Century would be affected by internal climate variability. Results show that there is almost no SLR benefit in the near term due to the large SLR variability due to the internal ocean dynamics. However, toward the end of the 21st century, the SLR benefit can be as much as a 26±1% reduction of the global mean SLR due to seawater thermal expansion. Regionally, the benefits from this mitigation for both near and long terms are heterogeneous. They vary from just a 11±5% SLR reduction in Melbourne, Australia to a 35±6% reduction in London. The processes contributing to these regional differences are the coupling of the wind-driven ocean circulation with the decadal scale sea surface temperature mode in the Pacific and Southern Oceans, and the changes of the thermohaline circulation and the mid-latitude air-sea coupling in the Atlantic.

Sea level rise drives increased tidal flooding frequency at tide gauges along the U.S. East and Gulf Coasts: Projections for 2030 and 2045.

PubMed

Dahl, Kristina A; Fitzpatrick, Melanie F; Spanger-Siegfried, Erika

2017-01-01

Tidal flooding is among the most tangible present-day effects of global sea level rise. Here, we utilize a set of NOAA tide gauges along the U.S. East and Gulf Coasts to evaluate the potential impact of future sea level rise on the frequency and severity of tidal flooding. Using the 2001-2015 time period as a baseline, we first determine how often tidal flooding currently occurs. Using localized sea level rise projections based on the Intermediate-Low, Intermediate-High, and Highest projections from the U.S. National Climate Assessment, we then determine the frequency and extent of such flooding at these locations for two near-term time horizons: 2030 and 2045. We show that increases in tidal flooding will be substantial and nearly universal at the 52 locations included in our analysis. Long before areas are permanently inundated, the steady creep of sea level rise will force many communities to grapple with chronic high tide flooding in the next 15 to 30 years.

Sea level rise drives increased tidal flooding frequency at tide gauges along the U.S. East and Gulf Coasts: Projections for 2030 and 2045

PubMed Central

Fitzpatrick, Melanie F.; Spanger-Siegfried, Erika

2017-01-01

Tidal flooding is among the most tangible present-day effects of global sea level rise. Here, we utilize a set of NOAA tide gauges along the U.S. East and Gulf Coasts to evaluate the potential impact of future sea level rise on the frequency and severity of tidal flooding. Using the 2001–2015 time period as a baseline, we first determine how often tidal flooding currently occurs. Using localized sea level rise projections based on the Intermediate-Low, Intermediate-High, and Highest projections from the U.S. National Climate Assessment, we then determine the frequency and extent of such flooding at these locations for two near-term time horizons: 2030 and 2045. We show that increases in tidal flooding will be substantial and nearly universal at the 52 locations included in our analysis. Long before areas are permanently inundated, the steady creep of sea level rise will force many communities to grapple with chronic high tide flooding in the next 15 to 30 years. PMID:28158209

An improved empirical dynamic control system model of global mean sea level rise and surface temperature change

NASA Astrophysics Data System (ADS)

Wu, Qing; Luu, Quang-Hung; Tkalich, Pavel; Chen, Ge

2018-04-01

Having great impacts on human lives, global warming and associated sea level rise are believed to be strongly linked to anthropogenic causes. Statistical approach offers a simple and yet conceptually verifiable combination of remotely connected climate variables and indices, including sea level and surface temperature. We propose an improved statistical reconstruction model based on the empirical dynamic control system by taking into account the climate variability and deriving parameters from Monte Carlo cross-validation random experiments. For the historic data from 1880 to 2001, we yielded higher correlation results compared to those from other dynamic empirical models. The averaged root mean square errors are reduced in both reconstructed fields, namely, the global mean surface temperature (by 24-37%) and the global mean sea level (by 5-25%). Our model is also more robust as it notably diminished the unstable problem associated with varying initial values. Such results suggest that the model not only enhances significantly the global mean reconstructions of temperature and sea level but also may have a potential to improve future projections.

Regional Sea Level Changes and Projections over North Pacific Driven by Air-sea interaction and Inter-basin Teleconnections

NASA Astrophysics Data System (ADS)

Li, X.; Zhu, J.; Xie, S. P.

2017-12-01

After the launch of the TOPEX/Poseidon satellite since 1992, a series of regional sea level changes have been observed. The northwestern Pacific is among the most rapid sea-level-rise regions all over the world. The rising peak occurs around 40°N, with the value reaching 15cm in the past two decades. Moreover, when investigating the projection of global sea level changes using CMIP5 rcp simulations, we found that the northwestern Pacific remains one of the most rapid sea-level-rise regions in the 21st century. To investigate the physical dynamics of present and future sea level changes over the Pacific, we performed a series of numerical simulations with a hierarchy of climate models, including earth system model, ocean model, and atmospheric models, with different complexity. Simulation results indicate that this regional sea level change during the past two decades is mainly caused by the shift of the Kuroshio, which is largely driven by the surface wind anomaly associated with an intensified and northward shifted north Pacific sub-tropical high. Further analysis and simulations show that these changes of sub-tropical high can be primarily attributed to the regional SST forcing from the Pacific Decadal Oscillation, and the remote SST forcings from the tropical Atlantic and the Indian Ocean. In the rcp scenario, on the other hand, two processes are crucial. Firstly, the meridional temperature SST gradient drives a northward wind anomaly across the equator, raising the sea level all over the North Pacific. Secondly, the atmospheric circulation changes around the sub-tropical Pacific further increase the sea level of the North Western Pacific. The coastal region around the Northwest Pacific is the most densely populated region around the world, therefore more attention must be paid to the sea level changes over this region, as suggested by our study.

Building more effective sea level rise models for coastal management

NASA Astrophysics Data System (ADS)

Kidwell, D.; Buckel, C.; Collini, R.; Meckley, T.

2017-12-01

For over a decade, increased attention on coastal resilience and adaptation to sea level rise has resulted in a proliferation of predictive models and tools. This proliferation has enhanced our understanding of our vulnerability to sea level rise, but has also led to stakeholder fatigue in trying to realize the value of each advancement. These models vary in type and complexity ranging from GIS-based bathtub viewers to modeling systems that dynamically couple complex biophysical and geomorphic processes. These approaches and capabilities typically have the common purpose using scenarios of global and regional sea level change to inform adaptation and mitigation. In addition, stakeholders are often presented a plethora of options to address sea level rise issues from a variety of agencies, academics, and consulting firms. All of this can result in confusion, misapplication of a specific model/tool, and stakeholder feedback of "no more new science or tools, just help me understand which one to use". Concerns from stakeholders have led to the question; how do we move forward with sea level rise modeling? This presentation will provide a synthesis of the experiences and feedback derived from NOAA's Ecological Effects of Sea level Rise (EESLR) program to discuss the future of predictive sea level rise impact modeling. EESLR is an applied research program focused on the advancement of dynamic modeling capabilities in collaboration with local and regional stakeholders. Key concerns from stakeholder engagement include questions about model uncertainty, approaches for model validation, and a lack of cross-model comparisons. Effective communication of model/tool products, capabilities, and results is paramount to address these concerns. Looking forward, the most effective predictions of sea level rise impacts on our coast will be attained through a focus on coupled modeling systems, particularly those that connect natural processes and human response.

Adapting to Rising Sea Level: A Florida Perspective

NASA Astrophysics Data System (ADS)

Parkinson, Randall W.

2009-07-01

Global climate change and concomitant rising sea level will have a profound impact on Florida's coastal and marine systems. Sea-level rise will increase erosion of beaches, cause saltwater intrusion into water supplies, inundate coastal marshes and other important habitats, and make coastal property more vulnerable to erosion and flooding. Yet most coastal areas are currently managed under the premise that sea-level rise is not significant and the shorelines are static or can be fixed in place by engineering structures. The new reality of sea-level rise and extreme weather due to climate change requires a new style of planning and management to protect resources and reduce risk to humans. Scientists must: (1) assess existing coastal vulnerability to address short term management issues and (2) model future landscape change and develop sustainable plans to address long term planning and management issues. Furthermore, this information must be effectively transferred to planners, managers, and elected officials to ensure their decisions are based upon the best available information. While there is still some uncertainty regarding the details of rising sea level and climate change, development decisions are being made today which commit public and private investment in real estate and associated infrastructure. With a design life of 30 yrs to 75 yrs or more, many of these investments are on a collision course with rising sea level and the resulting impacts will be significant. In the near term, the utilization of engineering structures may be required, but these are not sustainable and must ultimately yield to "managed withdrawal" programs if higher sea-level elevations or rates of rise are forthcoming. As an initial step towards successful adaptation, coastal management and planning documents (i.e., comprehensive plans) must be revised to include reference to climate change and rising sea-level.

Carbon choices determine US cities committed to futures below sea level

PubMed Central

Strauss, Benjamin H.; Kulp, Scott; Levermann, Anders

2015-01-01

Anthropogenic carbon emissions lock in long-term sea-level rise that greatly exceeds projections for this century, posing profound challenges for coastal development and cultural legacies. Analysis based on previously published relationships linking emissions to warming and warming to rise indicates that unabated carbon emissions up to the year 2100 would commit an eventual global sea-level rise of 4.3–9.9 m. Based on detailed topographic and population data, local high tide lines, and regional long-term sea-level commitment for different carbon emissions and ice sheet stability scenarios, we compute the current population living on endangered land at municipal, state, and national levels within the United States. For unabated climate change, we find that land that is home to more than 20 million people is implicated and is widely distributed among different states and coasts. The total area includes 1,185–1,825 municipalities where land that is home to more than half of the current population would be affected, among them at least 21 cities exceeding 100,000 residents. Under aggressive carbon cuts, more than half of these municipalities would avoid this commitment if the West Antarctic Ice Sheet remains stable. Similarly, more than half of the US population-weighted area under threat could be spared. We provide lists of implicated cities and state populations for different emissions scenarios and with and without a certain collapse of the West Antarctic Ice Sheet. Although past anthropogenic emissions already have caused sea-level commitment that will force coastal cities to adapt, future emissions will determine which areas we can continue to occupy or may have to abandon. PMID:26460051

Carbon choices determine US cities committed to futures below sea level.

PubMed

Strauss, Benjamin H; Kulp, Scott; Levermann, Anders

2015-11-03

Anthropogenic carbon emissions lock in long-term sea-level rise that greatly exceeds projections for this century, posing profound challenges for coastal development and cultural legacies. Analysis based on previously published relationships linking emissions to warming and warming to rise indicates that unabated carbon emissions up to the year 2100 would commit an eventual global sea-level rise of 4.3-9.9 m. Based on detailed topographic and population data, local high tide lines, and regional long-term sea-level commitment for different carbon emissions and ice sheet stability scenarios, we compute the current population living on endangered land at municipal, state, and national levels within the United States. For unabated climate change, we find that land that is home to more than 20 million people is implicated and is widely distributed among different states and coasts. The total area includes 1,185-1,825 municipalities where land that is home to more than half of the current population would be affected, among them at least 21 cities exceeding 100,000 residents. Under aggressive carbon cuts, more than half of these municipalities would avoid this commitment if the West Antarctic Ice Sheet remains stable. Similarly, more than half of the US population-weighted area under threat could be spared. We provide lists of implicated cities and state populations for different emissions scenarios and with and without a certain collapse of the West Antarctic Ice Sheet. Although past anthropogenic emissions already have caused sea-level commitment that will force coastal cities to adapt, future emissions will determine which areas we can continue to occupy or may have to abandon.

Sea-level rise and its possible impacts given a 'beyond 4°C world' in the twenty-first century.

PubMed

Nicholls, Robert J; Marinova, Natasha; Lowe, Jason A; Brown, Sally; Vellinga, Pier; de Gusmão, Diogo; Hinkel, Jochen; Tol, Richard S J

2011-01-13

The range of future climate-induced sea-level rise remains highly uncertain with continued concern that large increases in the twenty-first century cannot be ruled out. The biggest source of uncertainty is the response of the large ice sheets of Greenland and west Antarctica. Based on our analysis, a pragmatic estimate of sea-level rise by 2100, for a temperature rise of 4°C or more over the same time frame, is between 0.5 m and 2 m--the probability of rises at the high end is judged to be very low, but of unquantifiable probability. However, if realized, an indicative analysis shows that the impact potential is severe, with the real risk of the forced displacement of up to 187 million people over the century (up to 2.4% of global population). This is potentially avoidable by widespread upgrade of protection, albeit rather costly with up to 0.02 per cent of global domestic product needed, and much higher in certain nations. The likelihood of protection being successfully implemented varies between regions, and is lowest in small islands, Africa and parts of Asia, and hence these regions are the most likely to see coastal abandonment. To respond to these challenges, a multi-track approach is required, which would also be appropriate if a temperature rise of less than 4°C was expected. Firstly, we should monitor sea level to detect any significant accelerations in the rate of rise in a timely manner. Secondly, we need to improve our understanding of the climate-induced processes that could contribute to rapid sea-level rise, especially the role of the two major ice sheets, to produce better models that quantify the likely future rise more precisely. Finally, responses need to be carefully considered via a combination of climate mitigation to reduce the rise and adaptation for the residual rise in sea level. In particular, long-term strategic adaptation plans for the full range of possible sea-level rise (and other change) need to be widely developed.

Preliminary investigation of the effects of sea-level rise on groundwater levels in New Haven, Connecticut

USGS Publications Warehouse

Bjerklie, David M.; Mullaney, John R.; Stone, Janet R.; Skinner, Brian J.; Ramlow, Matthew A.

2012-01-01

Global sea level rose about 0.56 feet (ft) (170 millimeters (mm)) during the 20th century. Since the 1960s, sea level has risen at Bridgeport, Connecticut, about 0.38 ft (115 mm), at a rate of 0.008 ft (2.56 mm + or - 0.58 mm) per year. With regional subsidence, and with predicted global climate change, sea level is expected to continue to rise along the northeast coast of the United States through the 21st century. Increasing sea levels will cause groundwater levels in coastal areas to rise in order to adjust to the new conditions. Some regional climate models predict wetter climate in the northeastern United States under some scenarios. Scenarios for the resulting higher groundwater levels have the potential to inundate underground infrastructure in lowlying coastal cities. New Haven is a coastal city in Connecticut surrounded and bisected by tidally affected waters. Monitoring of water levels in wells in New Haven from August 2009 to July 2010 indicates the complex effects of urban influence on groundwater levels. The response of groundwater levels to recharge and season varied considerably from well to well. Groundwater temperatures varied seasonally, but were warmer than what was typical for Connecticut, and they seem to reflect the influence of the urban setting, including the effects of conduits for underground utilities. Specific conductance was elevated in many of the wells, indicating the influence of urban activities or seawater in Long Island Sound. A preliminary steady-state model of groundwater flow for part of New Haven was constructed using MODFLOW to simulate current groundwater levels (2009-2010) and future groundwater levels based on scenarios with a rise of 3 ft (0.91 meters (m)) in sea level, which is predicted for the end of the 21st century. An additional simulation was run assuming a 3-ft rise in sea level combined with a 12-percent increase in groundwater recharge. The model was constructed from existing hydrogeologic information for the New Haven area and from new information on groundwater levels collected during October 2009-June 2010. For the scenario with a 3-ft rise in sea level and no increase in recharge, simulated groundwater levels near the coast rose 3 ft; this increased water level tapered off toward a discharge area at the only nontidal stream in the study area. Simulated stream discharge increased at the nontidal stream because of the increased gradient. Although groundwater levels rose, the simulated difference between the groundwater levels in the aquifer and the increased sea level declined, indicating that the depth to the interface between freshwater and saltwater may possibly decline. Simulated water levels were affected by rise in sea level even in areas where the water table was at 17-24 ft (5.2-7.3 m) above current (2011) sea level. For the scenario with increased recharge, simulated groundwater levels were as much as an additional foot higher at some locations in the study area. The results of this preliminary investigation indicate that groundwater levels in coastal areas can be expected to rise and may rise higher if groundwater recharge also increases. This finding has implications for the disposal of stormwater through infiltration, a low-impact development practice designed to improve water quality and reduce overland peak discharge. Other implications include increased risk of basement flooding and increased groundwater seepage into underground sewer pipes and utility corridors in some areas. These implications will present engineering challenges to New Haven and Yale University. The preliminary model developed for this study can be the starting point for further simulation of future alternative scenarios for sea-level rise and recharge. Further simulations could identify those areas of New Haven where infrastructure may be at greatest risk from rising levels of groundwater. The simulations described in this report have limitations due to the preliminary scope of the work. Approaches to improve simulations include but are not limited to incorporating: * The variable density of seawater into the model in order to understand the current and future location of the interface between freshwater and saltwater; * Collection of additional data in order to better resolve temporal and spatial patterns in water levels in the aquifer; * Improved estimates of recharge through direct and indirect measurements of freshwater discharge from the study area; and * Transient simulations for greater understanding of the amount of time required for water levels and the position of the interface between freshwater and saltwater to adjust to changes in sea level and recharge.

Sea level rise with warming above 2 degree

NASA Astrophysics Data System (ADS)

Jevrejeva, Svetlana; Jackson, Luke; Riva, Riccardo; Grinsted, Aslak; Moore, John

2017-04-01

Holding the increase in the global average temperature to below 2 °C above pre-industrial levels, and pursuing efforts to limit the temperature increase to 1.5 °C, has been agreed by the representatives of the 196 parties of United Nations, as an appropriate threshold beyond which climate change risks become unacceptably high. Sea level rise is one of the most damaging aspects of warming climate for the more than 600 million people living in low-elevation coastal areas less than 10 meters above sea level. Fragile coastal ecosystems and increasing concentrations of population and economic activity in coastal areas, are reasons why future sea level rise is one of the most damaging aspects of the warming climate. Furthermore, sea level is set to continue to rise for centuries after greenhouse gas emissions concentrations are stabilised due to system inertia and feedback time scales. Impact, risk, adaptation policies and long-term decision making in coastal areas depend on regional and local sea level rise projections and local projections can differ substantially from the global one. Here we provide probabilistic sea level rise projections for the global coastline with warming above the 2 degree goal. A warming of 2°C makes global ocean rise on average by 20 cm, but more than 90% of coastal areas will experience greater rises, 40 cm along the Atlantic coast of North America and Norway, due to ocean dynamics. If warming continues above 2°C, then by 2100 sea level will rise with speeds unprecedented throughout human civilization, reaching 0.9 m (median), and 80% of the global coastline will exceed the global ocean sea level rise upper 95% confidence limit of 1.8 m. Coastal communities of rapidly expanding cities in the developing world, small island states, and vulnerable tropical coastal ecosystems will have a very limited time after mid-century to adapt to sea level rises.

North Atlantic sea-level variability during the last millennium

NASA Astrophysics Data System (ADS)

Gehrels, Roland; Long, Antony; Saher, Margot; Barlow, Natasha; Blaauw, Maarten; Haigh, Ivan; Woodworth, Philip

2014-05-01

Climate modelling studies have demonstrated that spatial and temporal sea-level variability observed in North Atlantic tide-gauge records is controlled by a complex array of processes, including ice-ocean mass exchange, freshwater forcing, steric changes, changes in wind fields, and variations in the speed of the Gulf Stream. Longer records of sea-level change, also covering the pre-industrial period, are important as a 'natural' and long-term baseline against which to test model performance and to place recent and future sea-level changes and ice-sheet change into a long-term context. Such records can only be reliably and continuously reconstructed from proxy methods. Salt marshes are capable of recording decimetre-scale sea-level variations with high precision and accuracy. In this paper we present four new high-resolution proxy records of (sub-) decadal sea-level variability reconstructed from salt-marsh sediments in Iceland, Nova Scotia, Maine and Connecticut that span the past 400 to 900 years. Our records, based on more than 100 new radiocarbon analyses, Pb-210 and Cs-137 measurements as well as other biological and geochemical age markers, together with hundreds of new microfossil observations from contemporary and fossil salt marshes, capture not only the rapid 20th century sea-level rise, but also small-scale (decimetre, multi-decadal) sea-level fluctuations during preceding centuries. We show that in Iceland three periods of rapid sea-level rise are synchronous with the three largest positive shifts of the reconstructed North Atlantic Oscillation (NAO) index. Along the North American east coast we compare our data with salt-marsh records from New Jersey, North Carolina and Florida and observe a trend of increased pre-industrial sea-level variability from south to north (Florida to Nova Scotia). Mass changes and freshwater forcing cannot explain this pattern. Based on comparisons with instrumental sea-level data and modelling studies we hypothesise that multi-decadal to centennial changes in wind and air pressure are more important than mass flux from land-based ice as drivers of North Atlantic sea-level variability during the last millennium.

The vulnerability of Indo-Pacific mangrove forests to sea-level rise

USGS Publications Warehouse

Lovelock, Catherine E.; Cahoon, Donald R.; Friess, Daniel A.; Guntenspergen, Glenn R.; Krauss, Ken W.; Reef, Ruth; Rogers, Kerrylee; Saunders, Megan L.; Sidik, Frida; Swales, Andrew; Saintilan, Neil; Thuyen, Le Xuan; Triet, Tran

2015-01-01

Sea-level rise can threaten the long-term sustainability of coastal communities and valuable ecosystems such as coral reefs, salt marshes and mangroves. Mangrove forests have the capacity to keep pace with sea-level rise and to avoid inundation through vertical accretion of sediments, which allows them to maintain wetland soil elevations suitable for plant growth. The Indo-Pacific region holds most of the world’s mangrove forests, but sediment delivery in this region is declining, owing to anthropogenic activities such as damming of rivers. This decline is of particular concern because the Indo-Pacific region is expected to have variable, but high, rates of future sea-level rise. Here we analyse recent trends in mangrove surface elevation changes across the Indo-Pacific region using data from a network of surface elevation table instruments. We find that sediment availability can enable mangrove forests to maintain rates of soil-surface elevation gain that match or exceed that of sea-level rise, but for 69 per cent of our study sites the current rate of sea-level rise exceeded the soil surface elevation gain. We also present a model based on our field data, which suggests that mangrove forests at sites with low tidal range and low sediment supply could be submerged as early as 2070.

The vulnerability of Indo-Pacific mangrove forests to sea-level rise.

PubMed

Lovelock, Catherine E; Cahoon, Donald R; Friess, Daniel A; Guntenspergen, Glenn R; Krauss, Ken W; Reef, Ruth; Rogers, Kerrylee; Saunders, Megan L; Sidik, Frida; Swales, Andrew; Saintilan, Neil; Thuyen, Le Xuan; Triet, Tran

2015-10-22

Sea-level rise can threaten the long-term sustainability of coastal communities and valuable ecosystems such as coral reefs, salt marshes and mangroves. Mangrove forests have the capacity to keep pace with sea-level rise and to avoid inundation through vertical accretion of sediments, which allows them to maintain wetland soil elevations suitable for plant growth. The Indo-Pacific region holds most of the world's mangrove forests, but sediment delivery in this region is declining, owing to anthropogenic activities such as damming of rivers. This decline is of particular concern because the Indo-Pacific region is expected to have variable, but high, rates of future sea-level rise. Here we analyse recent trends in mangrove surface elevation changes across the Indo-Pacific region using data from a network of surface elevation table instruments. We find that sediment availability can enable mangrove forests to maintain rates of soil-surface elevation gain that match or exceed that of sea-level rise, but for 69 per cent of our study sites the current rate of sea-level rise exceeded the soil surface elevation gain. We also present a model based on our field data, which suggests that mangrove forests at sites with low tidal range and low sediment supply could be submerged as early as 2070.

Interactions between sea-level rise and wave exposure on reef island dynamics in the Solomon Islands

NASA Astrophysics Data System (ADS)

Albert, Simon; Leon, Javier X.; Grinham, Alistair R.; Church, John A.; Gibbes, Badin R.; Woodroffe, Colin D.

2016-05-01

Low-lying reef islands in the Solomon Islands provide a valuable window into the future impacts of global sea-level rise. Sea-level rise has been predicted to cause widespread erosion and inundation of low-lying atolls in the central Pacific. However, the limited research on reef islands in the western Pacific indicates the majority of shoreline changes and inundation to date result from extreme events, seawalls and inappropriate development rather than sea-level rise alone. Here, we present the first analysis of coastal dynamics from a sea-level rise hotspot in the Solomon Islands. Using time series aerial and satellite imagery from 1947 to 2014 of 33 islands, along with historical insight from local knowledge, we have identified five vegetated reef islands that have vanished over this time period and a further six islands experiencing severe shoreline recession. Shoreline recession at two sites has destroyed villages that have existed since at least 1935, leading to community relocations. Rates of shoreline recession are substantially higher in areas exposed to high wave energy, indicating a synergistic interaction between sea-level rise and waves. Understanding these local factors that increase the susceptibility of islands to coastal erosion is critical to guide adaptation responses for these remote Pacific communities.

Looking Back to the Future: Insight on Anthropocene beaches from Holocene and Pleistocene barriers

NASA Astrophysics Data System (ADS)

Dougherty, A. J.; Choi, J. H.; Turney, C. S.; Dosseto, A.

2017-12-01

`Super' storms and accelerated rates of sea-level rise are forecast in the Anthropocene, but how coasts will respond (or even if they have started to be impacted) remain uncertain. The onset of this new anthropogenic age is considered mid-1900s when multiple indices including sea level exceed previous Holocene measurements. Centuries of sea surface elevation data, used to project an increase of up to 2m by 2100, show that the current rise started 200 years ago. Similar records of storms or shoreline evolution over these centennial time-scales do not exist. With empirical studies of coastal morphodynamics concentrated during decades of accelerated sea-level rise, present-day beaches can be considered Anthropocene features. To determine the future of vulnerable sandy shorelines, climate change scenarios of increased sea level and storm intensity have been combined with computer models integrating short-term process data with large-scale coastal evolution. The uncertainty in these models can be reduced with longer sea level and storm records as well as filling the gap between detailed beach profile/wave buoy data and generalized barrier stratigraphy. High-resolution chronostratigraphic models necessary to achieve this can be constructed using Light Detection And Ranging (LiDAR), Ground Penetrating Radar (GPR), and Optically Stimulated Luminescence (OSL). Combined GPR, OSL and LiDAR (GOaL) on prograded barriers enables analysis of shorelines back through time, by comparing behaviour since the onset of anthropogenic global warming to that in the preceding millennia. Extracting a record of coastal evolution prior to and since seas began to rise two centuries ago offers the opportunity to detect any difference indicating if/how shorelines have responded. In double barrier systems with composite Holocene and Pleistocene components GOaL can extend the Anthropocene record back to when seas were known to have been higher than today. To demonstrate the potential of GOaL, data collected over the past twenty years from North America and the South Pacific are presented; including some classic prograded barriers studied initially in the 1960s and extensively the 1980s. The resulting records of sea level, storms and sediment supply provide insight on, and input for modelling of, climate change and coastal evolution.

Can human activities alter the drowning fate of barrier islands?

NASA Astrophysics Data System (ADS)

Lorenzo-Trueba, J.; Ashton, A. D.; Jin, D.; Hoagland, P.; Kite-Powell, H.

2012-12-01

Low-lying coastal barriers face an uncertain future over the coming century and beyond as sea levels rise, with many projections suggesting end-of-century rates of sea-level rise as high or higher than 1 cm/yr. Geologically, such rates of sea-level rise have been experienced several thousand years ago and we can use our understanding of geological processes and sedimentary evidence to help unravel the dynamics of natural barriers experiencing sea-level rise. Along many modern coastal barriers, however, anthropic change, such as beach nourishment, dune construction, and emplacement of hard structures, plays a dominant role in coastline dynamics. A fundamental question to be addressed is whether human activities intended to preserve infrastructure and beach recreation may make wholesale collapse, or 'drowning,' of barrier systems more likely. Here we present a numerical modeling tool that couples natural processes and the human responses to these changes (and the subsequent of human responses on natural processes). Recent theoretical model development suggests that barriers are intrinsically morphodynamic features, responding to sea-level rise in complex ways through the interactions of marine processes and barrier overwash. Undeveloped coastal barriers would therefore respond to an accelerated sea-level rise in complex, less predictable manners than suggested by existing long-term models. We have developed a model that examines non-equilibrium cross-shore evolution of barrier systems at decadal to centennial temporal scales, focusing on the interactions between processes of shoreface evolution and overwash deposition. Model responses demonstrate two means of barrier collapse during sea-level rise: 'height drowning', which occurs when overwash fluxes are insufficient to maintain the landward migration rate required to keep in pace with sea-level rise, and 'width drowning', which occurs when the shoreface response is insufficient to maintain the barrier geometry during landward migration. The model also demonstrates the potential for discontinuous shoreline retreat, with alternating periods of barrier stability and rapid migration, even for constant rates of sea-level rise. Anthropic activities can strongly interact with these behaviors. In particular, considering only cross-shore processes, beach nourishment activities widen the beach and can affect shoreface fluxes, and dune building, which curtails the overwash process, can potentially enhance barrier drowning by reducing overwash fluxes. Furthermore, coastal protection activities of adjacent communities or even individual property holders can be uncoordinated or coordinated, with their effects coupled along the coast through coastal reorientation and gradients in alongshore sediment transport. In the coordinated framework, owners act in concert to alter the barrier based upon community benefits, whereas in the non-coordinated framework owners alter only their own property. Another important role in management is the perception of future sea-level-rise-associated losses—communities manage their coast differently depending on their adopted forecast for sea-level rise. We find that coordinated behavior coupled with natural processes can substantially affect the drowning scenarios from the individual decision-making process.

Pleistocene reduction of polar ice caps: Evidence from Cariaco Basin marine sediments

USGS Publications Warehouse

Poore, R.Z.; Dowsett, H.J.

2001-01-01

Sea level is projected to rise between 13 and 94 cm over the next 100 yr due to continued climate warming. The sea-level projections assume that polar ice sheets will remain stable or even increase on time scales of centuries, but controversial geologic evidence suggests that current polar ice sheets have been eliminated or greatly reduced during previous Pleistocene interglacials indicating that modern polar ice sheets have become unstable within the natural range of interglacial climates. Sea level may have been more than 20 m higher than today during a presumably very warm interglacial about 400 ka during marine isotope stage 11. Because of the implications for future sea level rise, additional study of the conflicting evidence for warmer conditions and higher sea level during marine isotope stage 11 is needed. Here we present microfossil and isotopic data from marine sediments of the Cariaco Basin supporting the interpretation that global sea level was 10-20 m higher than today during marine isotope stage 11. The increased sea level requires reduction in modern polar ice sheets and is consistent with the interpretation that the West Antarctic ice sheet and the Greenland ice sheet were absent or greatly reduced during marine isotope stage 11. Our results show a warm marine isotope stage 11 interglacial climate with sea level as high as or above modern sea level that lasted for 25 to 30 k.y. Variations in Earth's orbit around the sun (Milankovitch cycles) are considered to be a primary external force driving glacial-interglacial cycles. Current and marine isotope stage 11 Milankovitch forcing are very similar, suggesting that the present interglacial (Holocene) that began ca. 10 ka will continue for another 15 to 20 k.y. Therefore any anthropogenic climate warming will accelerate the natural process toward reduction in polar ice sheets. The potential for increased rates of sea level rise related to polar ice sheet decay should be considered as a potential natural hazard on centennial time scales.

Assessing hydrological effects of human interventions on coastal systems: numerical applications to the Venice Lagoon

NASA Astrophysics Data System (ADS)

Ferrarin, C.; Ghezzo, M.; Umgiesser, G.; Tagliapietra, D.; Camatti, E.; Zaggia, L.; Sarretta, A.

2013-05-01

The hydrological consequences of historical, contemporary and future human activities on a coastal system were investigated by means of numerical models. The changes in the morphology of the Lagoon of Venice during the last century result from the sedimentological response to the combined effects of human interventions on the environment and global changes. This study focuses on changes from 1927 to 2012 and includes the changes planned for the protection of the city of Venice from storm surges and exceptional tides under future sea level rise scenarios. The application of a hydrodynamic model allowed for the analysis of the morphological effects on the lagoon circulation, the interaction with the sea and the internal mixing processes. The absolute values of the exchange between the lagoon and sea increased from 1927 to 2002 (from 3900 to 4600 m3 s-1), while the daily fraction of lagoon water volume exchanged decreased. At the same time, the flattening of the lagoon and loss of morphological heterogeneity enhanced the internal mixing processes driven by the tide and wind, reducing thus the overall water renewal time from 11.9 days in 1927 to 10.8 days in 2002. Morphological changes during the last decade reduced the water exchange through the inlets and induced an increase of the basin-wide water renewal time of 0.5 day. In the future, Venice Lagoon will evolve to a more restricted environment due to sea level rise, which increases the lagoon volume, and periodical closure of the lagoon from the sea during flooding events, which reduces the communication with the open sea. Therefore, the flushing capacity of the lagoon will decrease considerably, especially in its central part. Furthermore, some considerations on the impact of the hydromorphological changes on the ecological dynamics are proposed.

The dynamic effects of sea level rise on low-gradient coastal landscapes: A review

USGS Publications Warehouse

Passeri, Davina L.; Hagen, Scott C.; Medeiros, Stephen C.; Bilskie, Matthew V.; Alizad, Karim; Wang, Dingbao

2015-01-01

Coastal responses to sea level rise (SLR) include inundation of wetlands, increased shoreline erosion, and increased flooding during storm events. Hydrodynamic parameters such as tidal ranges, tidal prisms, tidal asymmetries, increased flooding depths and inundation extents during storm events respond nonadditively to SLR. Coastal morphology continually adapts toward equilibrium as sea levels rise, inducing changes in the landscape. Marshes may struggle to keep pace with SLR and rely on sediment accumulation and the availability of suitable uplands for migration. Whether hydrodynamic, morphologic, or ecologic, the impacts of SLR are interrelated. To plan for changes under future sea levels, coastal managers need information and data regarding the potential effects of SLR to make informed decisions for managing human and natural communities. This review examines previous studies that have accounted for the dynamic, nonlinear responses of hydrodynamics, coastal morphology, and marsh ecology to SLR by implementing more complex approaches rather than the simplistic “bathtub” approach. These studies provide an improved understanding of the dynamic effects of SLR on coastal environments and contribute to an overall paradigm shift in how coastal scientists and engineers approach modeling the effects of SLR, transitioning away from implementing the “bathtub” approach. However, it is recommended that future studies implement a synergetic approach that integrates the dynamic interactions between physical and ecological environments to better predict the impacts of SLR on coastal systems.

The Impact of Climate Change on New York City's Coastal Flood Hazard: Increasing Flood Heights from the Pre-Industrial to 2300 CE

NASA Astrophysics Data System (ADS)

Garner, A. J.; Mann, M. E.; Emanuel, K.; Kopp, R. E.; Lin, N.; Alley, R. B.; Horton, B.; Deconto, R. M.; Donnelly, J. P.; Pollard, D.

2017-12-01

The flood hazard in New York City depends on both storm surges and rising sea levels. We combine modeled storm surges with probabilistic sea-level rise projections to assess future coastal inundation in New York City from the pre-industrial through 2300 CE. The storm surges are derived from large sets of synthetic tropical cyclones, downscaled from RCP 8.5 runs of three CMIP5 models. The sea-level rise projections include the collapse of the Antarctic ice sheet to assess future coastal inundation. CMIP5 models indicate that there will be minimal change in storm-surge heights from 2010 to 2100 or 2300, because the predicted strengthening of the strongest storms will be compensated by storm tracks moving offshore at the latitude of New York City. However, projected sea-level rise causes overall flood heights associated with tropical cyclones in New York City in coming centuries to increase greatly compared to pre-industrial or modern flood heights. We find that the 1-in-500-year flood event increases from 3.4 m above mean tidal level during 1970-2005 to 3.9 - 4.8 m above mean tidal level by 2080-2100, and ranges from 2.8 - 13.0 m above mean tidal level by 2280-2300. Further, we find that the return period of a 2.25 m flood has decreased from 500 years prior to 1800 to 25 years during 1970-2005, and further decreases to 5 years by 2030 - 2045 in 95% of our simulations.

Climate projections of spatial variations in coastal storm surges along the Gulf of Mexico and U.S. east coast

NASA Astrophysics Data System (ADS)

Yao, Zhigang; Xue, Zuo; He, Ruoying; Bao, Xianwen; Xie, Jun; Ge, Qian

2017-02-01

Using statistically downscaled atmospheric forcing, we performed a numerical investigation to evaluate future climate's impact on storm surges along the Gulf of Mexico and U.S. east coast. The focus is on the impact of climatic changes in wind pattern and surface pressure while neglecting sea level rise and other factors. We adapted the regional ocean model system (ROMS) to the study region with a mesh grid size of 7-10 km in horizontal and 18 vertical layers. The model was validated by a hindcast of the coastal sea levels in the winter of 2008. Model's robustness was confirmed by the good agreement between model-simulated and observed sea levels at 37 tidal gages. Two 10-year forecasts, one for the IPCC Pre-Industry (PI) and the other for the A1FI scenario, were conducted. The differences in model-simulated surge heights under the two climate scenarios were analyzed. We identified three types of responses in extreme surge heights to future climate: a clear decrease in Middle Atlantic Bight, an increase in the western Gulf of Mexico, and non-significant response for the remaining area. Such spatial pattern is also consistent with previous projections of sea surface winds and ocean wave heights.

Coastal vulnerability assessment of the Northern Gulf of Mexico to sea-level rise and coastal change

USGS Publications Warehouse

Pendleton, E.A.; Barras, J.A.; Williams, S.J.; Twichell, D.C.

2010-01-01

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise along the Northern Gulf of Mexico from Galveston, TX, to Panama City, FL. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rate, mean tidal range, and mean significant wave height. The rankings for each variable are combined and an index value is calculated for 1-kilometer grid cells along the coast. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. The CVI assessment presented here builds on an earlier assessment conducted for the Gulf of Mexico. Recent higher resolution shoreline change, land loss, elevation, and subsidence data provide the foundation for a better assessment for the Northern Gulf of Mexico. The areas along the Northern Gulf of Mexico that are likely to be most vulnerable to sea-level rise are parts of the Louisiana Chenier Plain, Teche-Vermillion Basin, and the Mississippi barrier islands, as well as most of the Terrebonne and Barataria Bay region and the Chandeleur Islands. These very high vulnerability areas have the highest rates of relative sea-level rise and the highest rates of shoreline change or land area loss. The information provided by coastal vulnerability assessments can be used in long-term coastal management and policy decision making.

Extremely low genetic diversity across mangrove taxa reflects past sea level changes and hints at poor future responses.

PubMed

Guo, Zixiao; Li, Xinnian; He, Ziwen; Yang, Yuchen; Wang, Wenqing; Zhong, Cairong; Greenberg, Anthony J; Wu, Chung-I; Duke, Norman C; Shi, Suhua

2018-04-01

The projected increases in sea levels are expected to affect coastal ecosystems. Tropical communities, anchored by mangrove trees and having experienced frequent past sea level changes, appear to be vibrant at present. However, any optimism about the resilience of these ecosystems is premature because the impact of past climate events may not be reflected in the current abundance. To assess the impact of historical sea level changes, we conducted an extensive genetic diversity survey on the Indo-Malayan coast, a hotspot with a large global mangrove distribution. A survey of 26 populations in six species reveals extremely low genome-wide nucleotide diversity and hence very small effective population sizes (N e ) in all populations. Whole-genome sequencing of three mangrove species further shows the decline in N e to be strongly associated with the speed of past changes in sea level. We also used a recent series of flooding events in Yalong Bay, southern China, to test the robustness of mangroves to sea level changes in relation to their genetic diversity. The events resulted in the death of half of the mangrove trees in this area. Significantly, less genetically diverse mangrove species suffered much greater destruction. The dieback was accompanied by a drastic reduction in local invertebrate biodiversity. We thus predict that tropical coastal communities will be seriously endangered as the global sea level rises. Well-planned coastal development near mangrove forests will be essential to avert this crisis. © 2017 John Wiley & Sons Ltd.

Communicating uncertainties in assessments of future sea level rise

NASA Astrophysics Data System (ADS)

Wikman-Svahn, P.

2013-12-01

How uncertainty should be managed and communicated in policy-relevant scientific assessments is directly connected to the role of science and the responsibility of scientists. These fundamentally philosophical issues influence how scientific assessments are made and how scientific findings are communicated to policymakers. It is therefore of high importance to discuss implicit assumptions and value judgments that are made in policy-relevant scientific assessments. The present paper examines these issues for the case of scientific assessments of future sea level rise. The magnitude of future sea level rise is very uncertain, mainly due to poor scientific understanding of all physical mechanisms affecting the great ice sheets of Greenland and Antarctica, which together hold enough land-based ice to raise sea levels more than 60 meters if completely melted. There has been much confusion from policymakers on how different assessments of future sea levels should be interpreted. Much of this confusion is probably due to how uncertainties are characterized and communicated in these assessments. The present paper draws on the recent philosophical debate on the so-called "value-free ideal of science" - the view that science should not be based on social and ethical values. Issues related to how uncertainty is handled in scientific assessments are central to this debate. This literature has much focused on how uncertainty in data, parameters or models implies that choices have to be made, which can have social consequences. However, less emphasis has been on how uncertainty is characterized when communicating the findings of a study, which is the focus of the present paper. The paper argues that there is a tension between on the one hand the value-free ideal of science and on the other hand usefulness for practical applications in society. This means that even if the value-free ideal could be upheld in theory, by carefully constructing and hedging statements characterizing scientific uncertainty, it will in most cases not be very useful for society. Instead, it is argued that scientific assessments that are used to inform societal decision-making should try to anticipate applications and aim to construct statements that characterize knowledge and uncertainty in a way that are more useful for those anticipated applications, even if this means that the value-free ideal cannot be upheld. This means that scientific assessments should ideally be intertwined with societal applications, and that co-produced knowledge engaging both scientists and end-users are likely to provide better and more useful assessments. The argument is illustrated using real examples from scientific assessments of future sea level rise, with special emphasis on the approaches used by the Intergovernmental Panel on Climate Change in the fourth assessment report from 2007, and the fifth assessment report due in September 2013. Finally, it is argued that recent developments in "bottom-up" and "robust" decision-making frameworks provide a way forward to remove many of the pitfalls and problems of communicating uncertainties in policy-relevant scientific assessments.

Increasing the highest storm surge in Busan harbor

NASA Astrophysics Data System (ADS)

Oh, Sang Myeong; Moon, Il-Ju; Kwon, Suk Jae

2017-04-01

One of the most pronounced effects of climate change in coastal regions is sea level rise and storm surges. Busan in particular, the fifth largest container handling port in the world, has suffered from serious storm surges and experienced a remarkable mean sea level (MSL) rise. This study investigates a long-term variation of annual maximum surge height (AMSH) using sea level data observed in Busan over 53 years (1962 2014). The decomposition of astronomical tides and surge components shows that the AMSH has increased 18 cm over 53 years (i.e., 3.5 mm/year), which is much larger than the MSL trend (2.5 mm/year) in Busan. This significant increase in AMSH is mostly explained by the increased intensity of landfall typhoons over the Korean peninsula (KP), which is associated with the increase of sea surface temperature and the decrease of vertical wind shear at mid-latitudes of the western North Pacific. In a projected future warming environment, the combination of an increasing MSL and AMSH will accelerate the occurrence of record-breaking extreme sea levels, which will be a potential threat in Busan harbor.

Surging Seas Risk Finder: A Tool for Local-Scale Flood Risk Assessments in Coastal Cities

NASA Astrophysics Data System (ADS)

Kulp, S. A.; Strauss, B.

2015-12-01

Local decision makers in coastal cities require accurate, accessible, and thorough assessments of flood exposure risk within their individual municipality, in their efforts to mitigate against damage due to future sea level rise. To fill this need, we have developed Climate Central's Surging Seas Risk Finder, an interactive data toolkit which presents our sea level rise and storm surge analysis for every coastal town, city, county, and state within the USA. Using this tool, policy makers can easily zoom in on their local place of interest to receive a detailed flood risk assessment, which synthesizes a wide range of features including total population, socially vulnerable population, housing, property value, road miles, power plants, schools, hospitals, and many other critical facilities. Risk Finder can also be used to identify specific points of interest in danger of exposure at different flood levels. Additionally, this tool provides localized storm surge probabilities and sea level rise projections at tidal gauges along the coast, so that users can quickly understand the risk of flooding in their area over the coming decades.

Global coastal flood hazard mapping

NASA Astrophysics Data System (ADS)

Eilander, Dirk; Winsemius, Hessel; Ward, Philip; Diaz Loaiza, Andres; Haag, Arjen; Verlaan, Martin; Luo, Tianyi

2017-04-01

Over 10% of the world's population lives in low-lying coastal areas (up to 10m elevation). Many of these areas are prone to flooding from tropical storm surges or extra-tropical high sea levels in combination with high tides. A 1 in 100 year extreme sea level is estimated to expose 270 million people and 13 trillion USD worth of assets to flooding. Coastal flood risk is expected to increase due to drivers such as ground subsidence, intensification of tropical and extra-tropical storms, sea level rise and socio-economic development. For better understanding of the hazard and drivers to global coastal flood risk, a globally consistent analysis of coastal flooding is required. In this contribution we present a comprehensive global coastal flood hazard mapping study. Coastal flooding is estimated using a modular inundation routine, based on a vegetation corrected SRTM elevation model and forced by extreme sea levels. Per tile, either a simple GIS inundation routine or a hydrodynamic model can be selected. The GIS inundation method projects extreme sea levels to land, taking into account physical obstructions and dampening of the surge level land inwards. For coastlines with steep slopes or where local dynamics play a minor role in flood behavior, this fast GIS method can be applied. Extreme sea levels are derived from the Global Tide and Surge Reanalysis (GTSR) dataset. Future sea level projections are based on probabilistic sea level rise for RCP 4.5 and RCP 8.5 scenarios. The approach is validated against observed flood extents from ground and satellite observations. The results will be made available through the online Aqueduct Global Flood Risk Analyzer of the World Resources Institute.

Future Wave Height Situation estimated by the Latest Climate Scenario around Funafuti Atoll, Tuvalu

NASA Astrophysics Data System (ADS)

Sato, D.; Yokoki, H.; Kuwahara, Y.; Yamano, H.; Kayanne, H.; Okajima, H.; Kawamiya, M.

2012-12-01

Sea-level rise due to the global warming is significant phenomenon to coastal region in the world. Especially the atoll islands, which are low-lying and narrow, have high vulnerability against the sea-level rise. Recently the improved future climate projection (MIROC-ESM) was provided by JAMSTEC, which adopted the latest climate scenarios based on the RCP (Representative Concentration Pathway) of the green house gasses. Wave field simulation including the latest sea-level rise pathway by MIROC-ESM was conducted to understand the change of significant wave heights in Funafuti Atoll, Tuvalu, which was an important factor to manage the coast protection. MIROC-ESM provides monthly sea surface height in the fine gridded world (1.5 degree near the equator). Wave field simulation was conducted using the climate scenario of RCP45 in which the radioactive forcing of the end of 21st century was stabilized to 4.5 W/m2. Sea-level rise ratio of every 10 years was calculated based on the historical data set from 1850 to 2005 and the estimated data set from 2006 to 2100. In that case, the sea-level increases by 10cm after 100 years. In this study, the numerical simulation of wave field at the rate of sea-level rise was carried out using the SWAN model. The wave and wind conditions around Funafuti atoll is characterized by two seasons that are the trade (Apr. - Nov.) and non-trade (Jan. - Mar., Dec.) wind season. Then, we set up the two seasonal boundary conditions for one year's simulation, which were calculated from ECMWF reanalysis data. Simulated results of significant wave heights are analyzed by the increase rate (%) calculated from the base results (Average for 2000 - 2005) and the results of 2100. Calculated increase rate of the significant wave height for both seasons was extremely high on the reef-flat. Maximum increase rates of the trade and non-trade wind season were 1817% and 686%, respectively. The southern part of the atoll has high increasing rate through the two seasons. In the non-trade wind season, the northern tip and the southern part of the island were higher increase rate in the lagoon-side coasts, which was about 7%, and the average rate was 3.4%. On the other hand, the average rate in the trade wind season was 5.0%. Ocean side coast has high increase rate through the two seasons. Especially, the very large rate was calculated in the northern part of the Fongafale Island locally. The DEM data in the middle of Fongafale Island, which is most populated area in the island, showed that the northern oceanic coast has wide and high storm ridge and the increase rate was extremely large there. In such coasts, sea-level rise due to global warming has same effect as storm surge due to tropical cyclone in the point of increasing the sea-level, although the time scale of them is not same. Thus we can consider that the calculated area with large increase rate has already experienced the high wave due to tropical cyclone, which was enabled to construct the wide and high storm ridge. This result indicated that the effective coastal management under the sea-level rise needs to understand not only the quantitative estimation of the future situation but also the protect potential constructed by the present wave and wind condition.

Increased Surface Wind Speeds Follow Diminishing Arctic Sea Ice

NASA Astrophysics Data System (ADS)

Mioduszewski, J.; Vavrus, S. J.; Wang, M.; Holland, M. M.; Landrum, L.

2017-12-01

Projections of Arctic sea ice through the end of the 21st century indicate the likelihood of a strong reduction in ice area and thickness in all seasons, leading to a substantial thermodynamic influence on the overlying atmosphere. This is likely to have an effect on winds over the Arctic Basin, due to changes in atmospheric stability and/or baroclinicity. Prior research on future Arctic wind changes is limited and has focused mainly on the practical impacts on wave heights in certain seasons. Here we attempt to identify patterns and likely mechanisms responsible for surface wind changes in all seasons across the Arctic, particularly those associated with sea ice loss in the marginal ice zone. Sea level pressure, near-surface (10 m) and upper-air (850 hPa) wind speeds, and lower-level dynamic and thermodynamic variables from the Community Earth System Model Large Ensemble Project (CESM-LE) were analyzed for the periods 1971-2000 and 2071-2100 to facilitate comparison between a present-day and future climate. Mean near-surface wind speeds over the Arctic Ocean are projected to increase by late century in all seasons but especially during autumn and winter, when they strengthen by up to 50% locally. The most extreme wind speeds in the 90th percentile change even more, increasing in frequency by over 100%. The strengthened winds are closely linked to decreasing lower-tropospheric stability resulting from the loss of sea ice cover and consequent surface warming (locally over 20 ºC warmer in autumn and winter). A muted pattern of these future changes is simulated in CESM-LE historical runs from 1920-2005. The enhanced winds near the surface are mostly collocated with weaker winds above the boundary layer during autumn and winter, implying more vigorous vertical mixing and a drawdown of high-momentum air.The implications of stronger future winds include increased coastal hazards and the potential for a positive feedback with sea ice by generating higher winds and greater wave activity. Our findings suggest that increasing winds, along with retreating sea ice and thawing permafrost, represent another important contributor to the growing problem of Arctic coastal erosion.

Reconstructing Mid- to Late Holocene Sea-Level Change from Coral Microatolls, French Polynesia

NASA Astrophysics Data System (ADS)

Hallmann, N.; Camoin, G.; Eisenhauer, A.; Vella, C.; Samankassou, E.; Botella, A.; Milne, G. A.; Pothin, V.; Dussouillez, P.; Fleury, J.

2017-12-01

Coral microatolls are sensitive low-tide recorders, as their vertical accretion is limited by the mean low water springs level, and can be considered therefore as high-precision recorders of sea-level change. They are of pivotal importance to resolving the rates and amplitudes of millennial-to-century scale changes during periods of relative climate stability such as the Mid- to Late Holocene, which serves as an important baseline of natural variability prior to the Anthropocene. It provides therefore a unique opportunity to study coastal response to sea-level rise, even if the rates of sea-level rise during the Mid- to Late Holocene were lower than the current rates and those expected in the near future. Mid- to Late Holocene relative sea-level changes in French Polynesia encompassing the last 6,000 years were reconstructed based on the coupling between absolute U/Th dating of in situ coral microatolls and their precise positioning via GPS RTK (Real Time Kinematic) measurements. The twelve studied islands represent ideal settings for accurate sea-level studies because: 1) they can be regarded as tectonically stable during the relevant period (slow subsidence), 2) they are located far from former ice sheets (far-field), 3) they are characterized by a low tidal amplitude, and 4) they cover a wide range of latitudes which produces significantly improved constraints on GIA (Glacial Isostatic Adjustment) model parameters. A sea-level rise of less than 1 m is recorded between 6 and 3-3.5 ka, and is followed by a gradual fall in sea level that started around 2.5 ka and persisted until the past few centuries. In addition, growth pattern analysis of coral microatolls allows the reconstruction of low-amplitude, high-frequency sea-level change on centennial to sub-decadal time scales. The reconstructed sea-level curve extends the Tahiti last deglacial sea-level curve [Deschamps et al., 2012, Nature, 483, 559-564], and is in good agreement with a geophysical model tuned to fit far-field deglacial records [Bassett et al., 2005, Science, 309, 925-928].

Reconstructing Mid- to Late Holocene sea-level change from coral microatolls, French Polynesia

NASA Astrophysics Data System (ADS)

Hallmann, N.; Camoin, G.; Eisenhauer, A.; Vella, C.; Samankassou, E.; Botella, A.; Milne, G. A.; Pothin, V.; Dussouillez, P.; Fleury, J.

2016-12-01

Coral microatolls are sensitive low-tide recorders, as their vertical accretion is limited by the mean low water springs level, and can be considered therefore as high-precision recorders of sea-level change. They are of pivotal importance to resolving the rates and amplitudes of millennial-to-century scale changes during periods of relative climate stability such as the Mid- to Late Holocene, which serves as an important baseline of natural variability prior to the industrial revolution. It provides therefore a unique opportunity to study coastal response to sea-level rise, even if the rates of sea-level rise during the Mid- to Late Holocene were lower than the current rates and those expected in the near future. Mid- to Late Holocene relative sea-level change in French Polynesia was reconstructed based on the coupling between absolute U/Th dating of in situ coral microatolls and their precise positioning via GPS RTK (Real Time Kinematic) measurements. The twelve studied islands represent ideal settings for accurate sea-level studies because: 1) they can be regarded as tectonically stable during the relevant period (slow subsidence), 2) they are located far from former ice sheets (far-field), 3) they are characterized by a low tidal amplitude, and 4) they cover a wide range of latitudes which produces significantly improved constraints on GIA (Glacial Isostatic Adjustment) model parameters. A sea-level rise of less than 1 m is recorded between 6 and 3-3.5 ka, and is followed by a gradual fall in sea level that started around 2.5 ka and persisted until the past few centuries. In addition, growth pattern analysis of coral microatolls allows the reconstruction of low-amplitude, high-frequency sea-level change on centennial to sub-decadal time scales. The reconstructed sea-level curve extends the Tahiti last deglacial sea-level curve [Deschamps et al., 2012, Nature, 483, 559-564], and is in good agreement with a geophysical model tuned to fit far-field deglacial records [Bassett et al., 2005, Science, 309, 925-928].

Modelling the increased frequency of extreme sea levels in the Ganges-Brahmaputra-Meghna delta due to sea level rise and other effects of climate change.

PubMed

Kay, S; Caesar, J; Wolf, J; Bricheno, L; Nicholls, R J; Saiful Islam, A K M; Haque, A; Pardaens, A; Lowe, J A

2015-07-01

Coastal flooding due to storm surge and high tides is a serious risk for inhabitants of the Ganges-Brahmaputra-Meghna (GBM) delta, as much of the land is close to sea level. Climate change could lead to large areas of land being subject to increased flooding, salinization and ultimate abandonment in West Bengal, India, and Bangladesh. IPCC 5th assessment modelling of sea level rise and estimates of subsidence rates from the EU IMPACT2C project suggest that sea level in the GBM delta region may rise by 0.63 to 0.88 m by 2090, with some studies suggesting this could be up to 0.5 m higher if potential substantial melting of the West Antarctic ice sheet is included. These sea level rise scenarios lead to increased frequency of high water coastal events. Any effect of climate change on the frequency and severity of storms can also have an effect on extreme sea levels. A shelf-sea model of the Bay of Bengal has been used to investigate how the combined effect of sea level rise and changes in other environmental conditions under climate change may alter the frequency of extreme sea level events for the period 1971 to 2099. The model was forced using atmospheric and oceanic boundary conditions derived from climate model projections and the future scenario increase in sea level was applied at its ocean boundary. The model results show an increased likelihood of extreme sea level events through the 21st century, with the frequency of events increasing greatly in the second half of the century: water levels that occurred at decadal time intervals under present-day model conditions occurred in most years by the middle of the 21st century and 3-15 times per year by 2100. The heights of the most extreme events tend to increase more in the first half of the century than the second. The modelled scenarios provide a case study of how sea level rise and other effects of climate change may combine to produce a greatly increased threat to life and property in the GBM delta by the end of this century.

Parental Effect of Long Acclimatization on Thermal Tolerance of Juvenile Sea Cucumber Apostichopus japonicus

PubMed Central

Dong, Yun-wei

2015-01-01

To evaluate the thermal resistance of marine invertebrates to elevated temperatures under scenarios of future climate change, it is crucial to understand parental effect of long acclimatization on thermal tolerance of offspring. To test whether there is parental effect of long acclimatization, adult sea cucumbers (Apostichopus japonicus) from the same broodstock were transplanted southward and acclimatized at high temperature in field mesocosms. Four groups of juvenile sea cucumbers whose parents experienced different durations of high temperature acclimatization were established. Upper thermal limits, oxygen consumption and levels of heat shock protein mRNA of juveniles was determined to compare thermal tolerance of individuals from different groups. Juvenile sea cucumbers whose parents experienced high temperature could acquire high thermal resistance. With the increase of parental exposure duration to high temperature, offspring became less sensitive to high temperature, as indicated by higher upper thermal limits (LT50), less seasonal variations of oxygen consumption, and stable oxygen consumption rates between chronic and acute thermal stress. The relatively high levels of constitutive expression of heat-shock proteins should contribute to the high thermal tolerance. Together, these results indicated that the existence of a parental effect of long acclimatization would increase thermal tolerance of juveniles and change the thermal sensitivity of sea cucumber to future climate change. PMID:26580550

Parental Effect of Long Acclimatization on Thermal Tolerance of Juvenile Sea Cucumber Apostichopus japonicus.

PubMed

Wang, Qing-Lin; Yu, Shan-Shan; Dong, Yun-Wei

2015-01-01

To evaluate the thermal resistance of marine invertebrates to elevated temperatures under scenarios of future climate change, it is crucial to understand parental effect of long acclimatization on thermal tolerance of offspring. To test whether there is parental effect of long acclimatization, adult sea cucumbers (Apostichopus japonicus) from the same broodstock were transplanted southward and acclimatized at high temperature in field mesocosms. Four groups of juvenile sea cucumbers whose parents experienced different durations of high temperature acclimatization were established. Upper thermal limits, oxygen consumption and levels of heat shock protein mRNA of juveniles was determined to compare thermal tolerance of individuals from different groups. Juvenile sea cucumbers whose parents experienced high temperature could acquire high thermal resistance. With the increase of parental exposure duration to high temperature, offspring became less sensitive to high temperature, as indicated by higher upper thermal limits (LT50), less seasonal variations of oxygen consumption, and stable oxygen consumption rates between chronic and acute thermal stress. The relatively high levels of constitutive expression of heat-shock proteins should contribute to the high thermal tolerance. Together, these results indicated that the existence of a parental effect of long acclimatization would increase thermal tolerance of juveniles and change the thermal sensitivity of sea cucumber to future climate change.

Engaging a moving target: Adapting to rates of climate change

NASA Astrophysics Data System (ADS)

Shayegh, S.; Caldeira, K.; Moreno-Cruz, J.

2015-12-01

Climate change is affecting the planet and its human and natural systems at an increasing rate. As temperatures continue to rise, the international community has increasingly been considering adaptation measures to prepare for future climate change. However, most discussion around adaptation strategies has focused on preparedness for some expected amount of climate change impacts, e.g. 2 meters sea level rise. In this study, we discuss adaptation to rates of change as an alternative conceptual framework for thinking about adaptation. Adaptation is not only about adapting to amounts of change, but the rate at which these changes occur is also critically important. We ground our discussion with an example of optimal coastal investment in the face of ongoing sea level rise. Sea level rise threatens coastal assets. Finite resources could be devoted to building infrastructure further inland or to building coastal defense systems. A possible policy response could be to create a "no-build" coastal buffer zone that anticipates a future higher sea level. We present a quantitative model that illustrates the interplay among various important factors (rate of sea level rise, discount rate, capital depreciation rate, attractiveness of coastal land, etc). For some cases, strategies that combine periodic defensive investments (e.g. dikes) with planned retreat can maximize welfare when adapting to rates of climate change. In other cases, planned retreat may be optimal. It is important to prepare for ongoing increasing amounts of climate change. Preparing for a fixed amount of climate change can lead to a suboptimal solution. Climate is likely to continue changing throughout this century and beyond. To reduce adverse climate impacts, ecosystems and human systems will need to continuously adapt to a moving target.

Evidence of exceptional oyster-reef resilience to fluctuations in sea level.

PubMed

Ridge, Justin T; Rodriguez, Antonio B; Fodrie, F Joel

2017-12-01

Ecosystems at the land-sea interface are vulnerable to rising sea level. Intertidal habitats must maintain their surface elevations with respect to sea level to persist via vertical growth or landward retreat, but projected rates of sea-level rise may exceed the accretion rates of many biogenic habitats. While considerable attention is focused on climate change over centennial timescales, relative sea level also fluctuates dramatically (10-30 cm) over month-to-year timescales due to interacting oceanic and atmospheric processes. To assess the response of oyster-reef ( Crassostrea virginica ) growth to interannual variations in mean sea level (MSL) and improve long-term forecasts of reef response to rising seas, we monitored the morphology of constructed and natural intertidal reefs over 5 years using terrestrial lidar. Timing of reef scans created distinct periods of high and low relative water level for decade-old reefs ( n  = 3) constructed in 1997 and 2000, young reefs ( n  = 11) constructed in 2011 and one natural reef (approximately 100 years old). Changes in surface elevation were related to MSL trends. Decade-old reefs achieved 2 cm/year growth, which occurred along higher elevations when MSL increased. Young reefs experienced peak growth (6.7 cm/year) at a lower elevation that coincided with a drop in MSL. The natural reef exhibited considerable loss during the low MSL of the first time step but grew substantially during higher MSL through the second time step, with growth peaking (4.3 cm/year) at MSL, reoccupying the elevations previously lost. Oyster reefs appear to be in dynamic equilibrium with short-term (month-to-year) fluctuations in sea level, evidencing notable resilience to future changes to sea level that surpasses other coastal biogenic habitat types. These growth patterns support the presence of a previously defined optimal growth zone that shifts correspondingly with changes in MSL, which can help guide oyster-reef conservation and restoration.

Evaluation of dynamic coastal response to sea-level rise modifies inundation likelihood

USGS Publications Warehouse

Lentz, Erika E.; Thieler, E. Robert; Plant, Nathaniel G.; Stippa, Sawyer R.; Horton, Radley M.; Gesch, Dean B.

2016-01-01

Sea-level rise (SLR) poses a range of threats to natural and built environments1, 2, making assessments of SLR-induced hazards essential for informed decision making3. We develop a probabilistic model that evaluates the likelihood that an area will inundate (flood) or dynamically respond (adapt) to SLR. The broad-area applicability of the approach is demonstrated by producing 30 × 30 m resolution predictions for more than 38,000 km2 of diverse coastal landscape in the northeastern United States. Probabilistic SLR projections, coastal elevation and vertical land movement are used to estimate likely future inundation levels. Then, conditioned on future inundation levels and the current land-cover type, we evaluate the likelihood of dynamic response versus inundation. We find that nearly 70% of this coastal landscape has some capacity to respond dynamically to SLR, and we show that inundation models over-predict land likely to submerge. This approach is well suited to guiding coastal resource management decisions that weigh future SLR impacts and uncertainty against ecological targets and economic constraints.

Vulnerability assessment of the impact of sea-level rise and flooding on the Moroccan coast: The case of the Mediterranean eastern zone

NASA Astrophysics Data System (ADS)

Snoussi, Maria; Ouchani, Tachfine; Niazi, Saïda

2008-04-01

The eastern part of the Mediterranean coast of Morocco is physically and socio-economically vulnerable to accelerated sea-level rise, due to its low topography and its high ecological and touristic value. Assessment of the potential land loss by inundation has been based on empirical approaches using a minimum inundation level of 2 m and a maximum inundation level of 7 m, where scenarios for future sea-level rise range from 200 to 860 mm, with a 'best estimate' of 490 mm. The socio-economic impacts have been based on two possible alternative futures: (1) a 'worst-case' scenario, obtained by combining the 'economic development first' scenario with the maximum inundation level; and (2) a 'best-case' scenario, by combining the 'sustainability first' scenario with the minimum inundation level. Inundation analysis, based on Geographical Information Systems and a modelling approach to erosion, has identified both locations and the socioeconomic sectors that are most at risk to accelerated sea-level rise. Results indicate that 24% and 59% of the area will be lost by flooding at minimum and maximum inundation levels, respectively. The most severely impacted sectors are expected to be the residential and recreational areas, agricultural land, and the natural ecosystem. Shoreline erosion will affect 50% and 70% of the total area in 2050 and 2100, respectively. Potential strategies to ameliorate the impact of seawater inundation include: wetland preservation; beach nourishment at tourist resorts; and the afforestation of dunes. As this coast is planned to become one of the most developed tourist resorts in Morocco by 2010, measures such as building regulation, urban growth planning and development of an Integrated Coastal Zone Management Plan, are recommended for the region.

Allowances for evolving coastal flood risk under uncertain local sea-level rise

NASA Astrophysics Data System (ADS)

Buchanan, M. K.; Kopp, R. E.; Oppenheimer, M.; Tebaldi, C.

2015-12-01

Sea-level rise (SLR) causes estimates of flood risk made under the assumption of stationary mean sea level to be biased low. However, adjustments to flood return levels made assuming fixed increases of sea level are also inaccurate when applied to sea level that is rising over time at an uncertain rate. To accommodate both the temporal dynamics of SLR and their uncertainty, we develop an Average Annual Design Life Level (AADLL) metric and associated SLR allowances [1,2]. The AADLL is the flood level corresponding to a time-integrated annual expected probability of occurrence (AEP) under uncertainty over the lifetime of an asset; AADLL allowances are the adjustment from 2000 levels that maintain current risk. Given non-stationary and uncertain SLR, AADLL flood levels and allowances provide estimates of flood protection heights and offsets for different planning horizons and different levels of confidence in SLR projections in coastal areas. Allowances are a function primarily of local SLR and are nearly independent of AEP. Here we employ probabilistic SLR projections [3] to illustrate the calculation of AADLL flood levels and allowances with a representative set of long-duration tide gauges along U.S. coastlines. [1] Rootzen et al., 2014, Water Resources Research 49: 5964-5972. [2] Hunter, 2013, Ocean Engineering 71: 17-27. [3] Kopp et al., 2014, Earth's Future 2: 383-406.

Sea level trends and NAO influences: The Bristol Channel/Severn Estuary

NASA Astrophysics Data System (ADS)

Phillips, M. R.; Crisp, S.

2010-09-01

Fifteen years, 1993 (earliest available) to 2007 inclusive of monthly mean and extreme (maximum and minimum) sea level data were assessed for four tide gauges located in the Bristol Channel (Mumbles and Ilfracombe) and Severn Estuary (Newport and Hinkley Point). Results showed decreasing maximum sea level trends and increasing minimum sea level trends, resulting in convergence. However, maximum extreme sea levels on the Welsh shoreline (Mumbles and Newport) were higher than corresponding locations on the English coast (Ilfracombe and Hinkley Point). Analysis showed that from 1995 to 1998 inclusive, maximum extreme sea levels were significantly higher at Mumbles (t = 2.342; df = 10; p < 0.05), Newport (t = 5.034; df = 13; p < 0.01) and Hinkley Point (t = 3.570; df = 13; p < 0.01) and were correlated to increased storm frequencies during these years. However, Ilfracombe (t = 1.472; df = 12; p > 0.05) did not demonstrate similar significance, possibly due to tide gauge location and coastal aspect, while tidal influences became more dominant as the tidal prism moved up the estuary. Actual mean sea levels (MSL) at Newport (t = 2.880; df = 14; p < 0.05) and Hinkley Point (t = 5.282; df = 14; p < 0.01) were significantly higher than predicted; at Mumbles (t = 2.673; df = 11; p < 0.05) they were significantly lower than predicted; while Ilfracombe (t = 1.989; df = 13; p > 0.05) once again showed no significant difference. Mumbles is the only location with off-shore sand waves and analysis suggested these as the cause of opposite trends. Sea level variation was strongly correlated to the North Atlantic Oscillation (NAO) Index, especially for maximum extreme sea levels during positive phases (R 2 = 86%), and higher positive or negative NAO Index values resulted in larger sea level ranges. Further analysis showed a rising Bristol Channel and Severn Estuary MSL trend of 2.4 mm yr - 1 and a 2050 MSL of 0.370 m is projected to inform future management. However, continuous updating and refinement of the sea level datasets will be needed.

Dynamic and static equilibrium sea level effects of Greenland Ice Sheet melt: An assessment of partially-coupled idealized water hosing experiments (Invited)

NASA Astrophysics Data System (ADS)

Kopp, R. E.; Mitrovica, J. X.; Griffies, S. M.; Yin, J.; Hay, C. C.; Stouffer, R. J.

2010-12-01

Regional sea level can deviate from mean global sea level because of both dynamic sea level (DSL) effects, resulting from oceanic and atmospheric circulation and temperature and salinity distributions, and changes in the static equilibrium (SE) sea level configuration, produced by the gravitational, elastic, and rotational effects of mass redistribution. Both effects will contribute to future sea level change, but because they are studied by two different subdisciplines -- climate modeling and glacial rebound modeling -- projections that attempt to combine both have to date been scarce. To compare their magnitude, we simulated the effects of Greenland Ice Sheet (GIS) melt by conducting idealized North Atlantic "water-hosing" experiments in a climate model unidirectionally coupled to a SE sea level model. At current rates of GIS melt, freshwater hosing experiments in fully coupled atmosphere-ocean general circulation models (AOGCMs) do not yield clear DSL trends but do generate DSL variability; comparing that variability to expected static equilibrium "fingerprints" suggests that at least about 40 years of observations are needed to detect the "fingerprints" of ice sheet melt at current Greenland melt rates of about 0.3 mm equivalent sea level (esl)/year. Accelerated melt rates of about 2--6 mm esl/y, as may occur later in the century, should be detectable above background DSL variability within less than a decade of their onset. At these higher melt rates, AOGCMs do yield clear DSL trends. In the GFDL CM 2.1 model, DSL trends are strongest in the western North Atlantic, while SE effects come to dominate in most of the ocean when melt exceeds about 20 cm esl.

Experimental investigation of channel avulsion frequency on river deltas under rising sea levels

NASA Astrophysics Data System (ADS)

Silvestre, J.; Chadwick, A. J.; Steele, S.; Lamb, M. P.

2017-12-01

River deltas are low-relief landscapes that are socioeconomically important; they are home to over half a billion people worldwide. Many deltas are built by cycles of lobe growth punctuated by abrupt channel shifts, or avulsions, which often reoccur at a similar location and with a regular frequency. Previous experimental work has investigated the effect of hydrodynamic backwater in controlling channel avulsion location and timing on deltas under constant sea level conditions, but it is unclear how sea-level rise impacts avulsion dynamics. We present results from a flume experiment designed to isolate the role of relative sea-level rise on the evolution of a backwater-influenced delta. The experiment was conducted in the river-ocean facility at Caltech, where a 7m long, 14cm wide alluvial river drains into a 6m by 3m "ocean" basin. The experimental delta grew under subcritical flow, a persistent backwater zone, and a range of sea level rise rates. Without sea level rise, lobe progradation produced in-channel aggradation and periodic avulsions every 3.6 ± 0.9 hours, which corresponded to when channels aggraded to approximately one-half of their flow depth. With a modest rate of sea-level rise (0.25 mm/hr), we observed enhanced aggradation in the backwater zone, causing channels to aggrade more quickly and avulse more frequently (every 2.1 ± 0.6 hours). In future work, we expect further increases in the rate of relative sea-level rise to cause avulsion frequency to decrease as the delta drowns and the backwater zone retreats upstream. Experimental results can serve as tests of numerical models that are needed for hazard mitigation and coastal sustainability efforts on drowning deltas.

How effective is albedo modification (solar radiation management geoengineering) in preventing sea-level rise from the Greenland Ice Sheet?

NASA Astrophysics Data System (ADS)

Applegate, Patrick J.; Keller, Klaus

2015-08-01

Albedo modification (AM) is sometimes characterized as a potential means of avoiding climate threshold responses, including large-scale ice sheet mass loss. Previous work has investigated the effects of AM on total sea-level rise over the present century, as well as AM’s ability to reduce long-term (≫103 yr) contributions to sea-level rise from the Greenland Ice Sheet (GIS). These studies have broken new ground, but neglect important feedbacks in the GIS system, or are silent on AM’s effectiveness over the short time scales that may be most relevant for decision-making (<103 yr). Here, we assess AM’s ability to reduce GIS sea-level contributions over decades to centuries, using a simplified ice sheet model. We drive this model using a business-as-usual base temperature forcing scenario, as well as scenarios that reflect AM-induced temperature stabilization or temperature drawdown. Our model results suggest that (i) AM produces substantial near-term reductions in the rate of GIS-driven sea-level rise. However, (ii) sea-level rise contributions from the GIS continue after AM begins. These continued sea level rise contributions persist for decades to centuries after temperature stabilization and temperature drawdown begin, unless AM begins in the next few decades. Moreover, (iii) any regrowth of the GIS is delayed by decades or centuries after temperature drawdown begins, and is slow compared to pre-AM rates of mass loss. Combined with recent work that suggests AM would not prevent mass loss from the West Antarctic Ice Sheet, our results provide a nuanced picture of AM’s possible effects on future sea-level rise.

A Bayesian network to predict coastal vulnerability to sea level rise

USGS Publications Warehouse

Gutierrez, B.T.; Plant, N.G.; Thieler, E.R.

2011-01-01

Sea level rise during the 21st century will have a wide range of effects on coastal environments, human development, and infrastructure in coastal areas. The broad range of complex factors influencing coastal systems contributes to large uncertainties in predicting long-term sea level rise impacts. Here we explore and demonstrate the capabilities of a Bayesian network (BN) to predict long-term shoreline change associated with sea level rise and make quantitative assessments of prediction uncertainty. A BN is used to define relationships between driving forces, geologic constraints, and coastal response for the U.S. Atlantic coast that include observations of local rates of relative sea level rise, wave height, tide range, geomorphic classification, coastal slope, and shoreline change rate. The BN is used to make probabilistic predictions of shoreline retreat in response to different future sea level rise rates. Results demonstrate that the probability of shoreline retreat increases with higher rates of sea level rise. Where more specific information is included, the probability of shoreline change increases in a number of cases, indicating more confident predictions. A hindcast evaluation of the BN indicates that the network correctly predicts 71% of the cases. Evaluation of the results using Brier skill and log likelihood ratio scores indicates that the network provides shoreline change predictions that are better than the prior probability. Shoreline change outcomes indicating stability (-1 1 m/yr) was not well predicted. We find that BNs can assimilate important factors contributing to coastal change in response to sea level rise and can make quantitative, probabilistic predictions that can be applied to coastal management decisions. Copyright ?? 2011 by the American Geophysical Union.

Estimating Areas of Vulnerability: Sea Level Rise and Storm Surge Hazards in the National Parks

NASA Astrophysics Data System (ADS)

Caffrey, M.; Beavers, R. L.; Slayton, I. A.

2013-12-01

The University of Colorado Boulder in collaboration with the National Park Service has undertaken the task of compiling sea level change and storm surge data for 105 coastal parks. The aim of our research is to highlight areas of the park system that are at increased risk of rapid inundation as well as periodic flooding due to sea level rise and storms. This research will assist park managers and planners in adapting to climate change. The National Park Service incorporates climate change data into many of their planning documents and is willing to implement innovative coastal adaptation strategies. Events such as Hurricane Sandy highlight how impacts of coastal hazards will continue to challenge management of natural and cultural resources and infrastructure along our coastlines. This poster will discuss the current status of this project. We discuss the impacts of Hurricane Sandy as well as the latest sea level rise and storm surge modeling being employed in this project. In addition to evaluating various drivers of relative sea-level change, we discuss how park planners and managers also need to consider projected storm surge values added to sea-level rise magnitudes, which could further complicate the management of coastal lands. Storm surges occurring at coastal parks will continue to change the land and seascapes of these areas, with the potential to completely submerge them. The likelihood of increased storm intensity added to increasing rates of sea-level rise make predicting the reach of future storm surges essential for planning and adaptation purposes. The National Park Service plays a leading role in developing innovative strategies for coastal parks to adapt to sea-level rise and storm surge, whilst coastal storms are opportunities to apply highly focused responses.

Effects of ocean acidification and sea-level rise on coral reefs

USGS Publications Warehouse

Yates, K.K.; Moyer, R.P.

2010-01-01

U.S. Geological Survey (USGS) scientists are developing comprehensive records of historical and modern coral reef growth and calcification rates relative to changing seawater chemistry resulting from increasing atmospheric CO2 from the pre-industrial period to the present. These records will provide the scientific foundation for predicting future impacts of ocean acidification and sea-level rise on coral reef growth. Changes in coral growth rates in response to past changes in seawater pH are being examined by using cores from coral colonies.

Modeling barrier island response to sea-level rise in the Outer Banks, North Carolina

USGS Publications Warehouse

Moore, Laura J.; List, Jeffrey H.; Williams, S. Jeffress; Stolper, David

2007-01-01

An 8500-year Holocene simulation developed in GEOMBEST provides a possible scenario to explain the evolution of barrier coast between Rodanthe and Cape Hatteras, NC. Sensitivity analyses suggest that in the Outer Banks, the rate of sea-level rise is the most important factor in determining how barrier islands evolve. The Holocene simulation provides a basis for future simulations, which suggest that if sea level rises up to 0.88 m by AD 2100, as predicted by the highest estimates of the Intergovernmental Panel on Climate Change, the barrier in the study area may migrate on the order of 2.5 times more rapidly than at present. If sea level rises beyond IPCC predictions to reach 1.4–1.9 m above modern sea level by AD 2100, model results suggest that barrier islands in the Outer Banks may become vulnerable to threshold collapse, disintegrating during storm events, by the end of the next century. Consistent with sensitivity analyses, additional simulations indicate that anthropogenic activities, such as increasing the rate of sediment supply through beach nourishment, will only slightly affect barrier island migration rates and barrier island vulnerability to collapse.

Nuisance Flooding and Relative Sea-Level Rise: the Importance of Present-Day Land Motion.

PubMed

Karegar, Makan A; Dixon, Timothy H; Malservisi, Rocco; Kusche, Jürgen; Engelhart, Simon E

2017-09-11

Sea-level rise is beginning to cause increased inundation of many low-lying coastal areas. While most of Earth's coastal areas are at risk, areas that will be affected first are characterized by several additional factors. These include regional oceanographic and meteorological effects and/or land subsidence that cause relative sea level to rise faster than the global average. For catastrophic coastal flooding, when wind-driven storm surge inundates large areas, the relative contribution of sea-level rise to the frequency of these events is difficult to evaluate. For small scale "nuisance flooding," often associated with high tides, recent increases in frequency are more clearly linked to sea-level rise and global warming. While both types of flooding are likely to increase in the future, only nuisance flooding is an early indicator of areas that will eventually experience increased catastrophic flooding and land loss. Here we assess the frequency and location of nuisance flooding along the eastern seaboard of North America. We show that vertical land motion induced by recent anthropogenic activity and glacial isostatic adjustment are contributing factors for increased nuisance flooding. Our results have implications for flood susceptibility, forecasting and mitigation, including management of groundwater extraction from coastal aquifers.

Explicit Simulation of Networks of Outlet Glaciers to Constrain Greenland's Sea Level Contribution

NASA Astrophysics Data System (ADS)

Ultee, E.; Bassis, J. N.

2017-12-01

Ice from the Greenland Ice Sheet drains to the ocean through hundreds of outlet glaciers, many of which are too small to be accurately resolved in continental-scale ice sheet models. Moreover, despite the fact that dynamic changes in Greenland outlet glaciers are currently responsible for about half of the ice sheet's contribution to global sea level, all but the largest are often excluded from major sea level assessments. We have previously developed and validated a simple model that simulates advance and retreat of networks of marine-terminating glaciers based on the perfect plastic approximation. Here we apply this model to a selection of forcing scenarios, representing both climate persistence and extreme scenarios, to constrain changes in calving flux from the most significant Greenland outlet glaciers. Our model can be implemented in standalone mode or as the calving module in a more sophisticated large-scale model, providing constraints on Greenland's future contribution to global sea level rise under a range of scenarios.

Evaluating coastal landscape response to sea-level rise in the northeastern United States: approach and methods

USGS Publications Warehouse

Lentz, Erika E.; Stippa, Sawyer R.; Thieler, E. Robert; Plant, Nathaniel G.; Gesch, Dean B.; Horton, Radley M.

2014-02-13

The U.S. Geological Survey is examining effects of future sea-level rise on the coastal landscape from Maine to Virginia by producing spatially explicit, probabilistic predictions using sea-level projections, vertical land movement rates (due to isostacy), elevation data, and land-cover data. Sea-level-rise scenarios used as model inputs are generated by using multiple sources of information, including Coupled Model Intercomparison Project Phase 5 models following representative concentration pathways 4.5 and 8.5 in the Intergovernmental Panel on Climate Change Fifth Assessment Report. A Bayesian network is used to develop a predictive coastal response model that integrates the sea-level, elevation, and land-cover data with assigned probabilities that account for interactions with coastal geomorphology as well as the corresponding ecological and societal systems it supports. The effects of sea-level rise are presented as (1) level of landscape submergence and (2) coastal response type characterized as either static (that is, inundation) or dynamic (that is, landform or landscape change). Results are produced at a spatial scale of 30 meters for four decades (the 2020s, 2030s, 2050s, and 2080s). The probabilistic predictions can be applied to landscape management decisions based on sea-level-rise effects as well as on assessments of the prediction uncertainty and need for improved data or fundamental understanding. This report describes the methods used to produce predictions, including information on input datasets; the modeling approach; model outputs; data-quality-control procedures; and information on how to access the data and metadata online.

Evaluating Coastal Landscape Response to Sea-Level Rise in the Northeastern United States - Approach and Methods

NASA Technical Reports Server (NTRS)

Lentz, Erika E.; Stippa, Sawyer R.; Thieler, E. Robert; Plant, Nathaniel G.; Gesch, Dean B.; Horton, Radley M.

2015-01-01

The U.S. Geological Survey is examining effects of future sea-level rise on the coastal landscape from Maine to Virginia by producing spatially explicit, probabilistic predictions using sea-level projections, vertical land movement rates (due to isostacy), elevation data, and land-cover data. Sea-level-rise scenarios used as model inputs are generated by using multiple sources of information, including Coupled Model Intercomparison Project Phase 5 models following representative concentration pathways 4.5 and 8.5 in the Intergovernmental Panel on Climate Change Fifth Assessment Report. A Bayesian network is used to develop a predictive coastal response model that integrates the sea-level, elevation, and land-cover data with assigned probabilities that account for interactions with coastal geomorphology as well as the corresponding ecological and societal systems it supports. The effects of sea-level rise are presented as (1) level of landscape submergence and (2) coastal response type characterized as either static (that is, inundation) or dynamic (that is, landform or landscape change). Results are produced at a spatial scale of 30 meters for four decades (the 2020s, 2030s, 2050s, and 2080s). The probabilistic predictions can be applied to landscape management decisions based on sea-level-rise effects as well as on assessments of the prediction uncertainty and need for improved data or fundamental understanding. This report describes the methods used to produce predictions, including information on input datasets; the modeling approach; model outputs; data-quality-control procedures; and information on how to access the data and metadata online.

De-confounding of Relations Between Land-Level and Sea-Level Change, Humboldt Bay, Northern California: Uncertain Predictions of Magnitude and Timing of Tectonic and Eustatic Processes

NASA Astrophysics Data System (ADS)

Gilkerson, W.; Leroy, T. H.; Patton, J. R.; Williams, T. B.

2010-12-01

Humboldt Bay in Northern California provides a unique opportunity to investigate the effects of relative sea level change on both native flora and maritime aquiculture as influenced by both tectonic and eustatic sea-level changes. This combination of superposed influences makes quantitatively predicting relative sea-level more uncertain and consumption of the results for public planning purposes exceedingly difficult. Public digestion for practical purposes is confounded by the fact that the uncertainty for eustatic sea-level changes is a magnitude issue while the uncertainty associated with the tectonic land level changes is both a magnitude and timing problem. Secondly, the public is less well informed regarding how crustal deformation contributes to relative sea-level change. We model the superposed effects of eustatic sea-level rise and tectonically driven land-level changes on the spatial distribution of habitats suitable to native eelgrass (Zostera marina) and oyster mariculture operations in Humboldt Bay. While these intertidal organisms were chosen primarily because they have vertically restricted spatial distributions that can be successfully modeled, the public awareness of their ecologic and economic importance is also well developed. We employ easy to understand graphics depicting conceptual ideas along with maps generated from the modeling results to develop locally relevant estimates of future sea level rise over the next 100 years, a time frame consistent with local planning. We bracket these estimates based on the range of possible vertical deformation changes. These graphic displays can be used as a starting point to propose local outcomes from global and regional relative sea-level changes with respect to changes in the distribution of suitable habitat for ecologically and economically valuable species. Currently the largest sources of uncertainty for changes in relative sea-level in the Humboldt Bay area are 1) the rate and magnitude of tectonic deformation throughout the earthquake cycle and 2) the stability and reliability of the tide gauges and other benchmarks assumed to be stable in the Humboldt Bay region.

The hazard of Sea Level Rise (SLR) in Greece: from scientific knowledge towards risk awareness of main actors

NASA Astrophysics Data System (ADS)

Dandoulaki, Miranda; Karymbalis, Efthimios; Yorgos, Melissourgos; Skordili, Sophia; Valkanou, Kanella

2014-05-01

A natural hazard that is expected to affect coastal areas in the near future is Sea-Level Rise (SLR) due to climate change. According to recent reports the eustatic sea-level rise caused by global warming will reach approximately 18-59 cm by the year 2100. Potential impacts of future sea-level rise include coastal erosion, frequent and intensified cyclonic activity and associated storm surge flooding that may affect the coastal zones, saltwater intrusion into groundwater aquifers, the inundation of ecologically significant wetlands, and threats to cultural and historical resources, as well as to infrastructure. The identification of sensitive sections of coasts and the assessment of potential impacts of SLR on these is therefore a fundamental, yet initial, step towards their protection. Greece has the most extensive coastline among all Mediterranean countries with most of the socio-economic activities concentrated along the coastal zone. Almost all big urban centres are coastal ones and the same stands for a great part of infrastructure (ports, airports, roads, electricity and telecommunications network etc). As a result, the impacts of a potential rise of the sea level are expected to seriously affect the entire country. The paper examines the vulnerability to SLR of coastal zones in Greece; however its main focus is how knowledge can lead to policy making and the protection of coastal areas. The main actors in respect to protection from SLR in Greece are identified and there is an attempt to pin point how the knowledge is communicated and shared between them. Barriers, bridges and gaps are detected as regards how information and knowledge lead to risk awareness and finally to the implementation of protection policies. A main finding of the paper is that SLR risk is far from becoming a policy priority in Greece, although steps are taken for addressing impacts attributed to SLR such as coastal erosion. In order to address this risk, there are many potential adaptation options starting from communication and enhanced awareness. But in today's situation of financial crisis, adaptation to SLR becomes even less of a priority, as everyday problems seem more urgent than future, long-term, uncertain risks.

Uncertainty quantification of Antarctic contribution to sea-level rise using the fast Elementary Thermomechanical Ice Sheet (f.ETISh) model

NASA Astrophysics Data System (ADS)

Bulthuis, Kevin; Arnst, Maarten; Pattyn, Frank; Favier, Lionel

2017-04-01

Uncertainties in sea-level rise projections are mostly due to uncertainties in Antarctic ice-sheet predictions (IPCC AR5 report, 2013), because key parameters related to the current state of the Antarctic ice sheet (e.g. sub-ice-shelf melting) and future climate forcing are poorly constrained. Here, we propose to improve the predictions of Antarctic ice-sheet behaviour using new uncertainty quantification methods. As opposed to ensemble modelling (Bindschadler et al., 2013) which provides a rather limited view on input and output dispersion, new stochastic methods (Le Maître and Knio, 2010) can provide deeper insight into the impact of uncertainties on complex system behaviour. Such stochastic methods usually begin with deducing a probabilistic description of input parameter uncertainties from the available data. Then, the impact of these input parameter uncertainties on output quantities is assessed by estimating the probability distribution of the outputs by means of uncertainty propagation methods such as Monte Carlo methods or stochastic expansion methods. The use of such uncertainty propagation methods in glaciology may be computationally costly because of the high computational complexity of ice-sheet models. This challenge emphasises the importance of developing reliable and computationally efficient ice-sheet models such as the f.ETISh ice-sheet model (Pattyn, 2015), a new fast thermomechanical coupled ice sheet/ice shelf model capable of handling complex and critical processes such as the marine ice-sheet instability mechanism. Here, we apply these methods to investigate the role of uncertainties in sub-ice-shelf melting, calving rates and climate projections in assessing Antarctic contribution to sea-level rise for the next centuries using the f.ETISh model. We detail the methods and show results that provide nominal values and uncertainty bounds for future sea-level rise as a reflection of the impact of the input parameter uncertainties under consideration, as well as a ranking of the input parameter uncertainties in the order of the significance of their contribution to uncertainty in future sea-level rise. In addition, we discuss how limitations posed by the available information (poorly constrained data) pose challenges that motivate our current research.

Synthesizing long-term sea level rise projections - the MAGICC sea level model v2.0

NASA Astrophysics Data System (ADS)

Nauels, Alexander; Meinshausen, Malte; Mengel, Matthias; Lorbacher, Katja; Wigley, Tom M. L.

2017-06-01

Sea level rise (SLR) is one of the major impacts of global warming; it will threaten coastal populations, infrastructure, and ecosystems around the globe in coming centuries. Well-constrained sea level projections are needed to estimate future losses from SLR and benefits of climate protection and adaptation. Process-based models that are designed to resolve the underlying physics of individual sea level drivers form the basis for state-of-the-art sea level projections. However, associated computational costs allow for only a small number of simulations based on selected scenarios that often vary for different sea level components. This approach does not sufficiently support sea level impact science and climate policy analysis, which require a sea level projection methodology that is flexible with regard to the climate scenario yet comprehensive and bound by the physical constraints provided by process-based models. To fill this gap, we present a sea level model that emulates global-mean long-term process-based model projections for all major sea level components. Thermal expansion estimates are calculated with the hemispheric upwelling-diffusion ocean component of the simple carbon-cycle climate model MAGICC, which has been updated and calibrated against CMIP5 ocean temperature profiles and thermal expansion data. Global glacier contributions are estimated based on a parameterization constrained by transient and equilibrium process-based projections. Sea level contribution estimates for Greenland and Antarctic ice sheets are derived from surface mass balance and solid ice discharge parameterizations reproducing current output from ice-sheet models. The land water storage component replicates recent hydrological modeling results. For 2100, we project 0.35 to 0.56 m (66 % range) total SLR based on the RCP2.6 scenario, 0.45 to 0.67 m for RCP4.5, 0.46 to 0.71 m for RCP6.0, and 0.65 to 0.97 m for RCP8.5. These projections lie within the range of the latest IPCC SLR estimates. SLR projections for 2300 yield median responses of 1.02 m for RCP2.6, 1.76 m for RCP4.5, 2.38 m for RCP6.0, and 4.73 m for RCP8.5. The MAGICC sea level model provides a flexible and efficient platform for the analysis of major scenario, model, and climate uncertainties underlying long-term SLR projections. It can be used as a tool to directly investigate the SLR implications of different mitigation pathways and may also serve as input for regional SLR assessments via component-wise sea level pattern scaling.

Habitability at the frontlines of sea level rise: a spatiotemporal analysis of settlements and coastal inundation in eight global sea level rise hotspots between 1990 and 2015

NASA Astrophysics Data System (ADS)

Rose, S. A.; Wrathall, D.

2017-12-01

Over the coming centuries and millennia, sea level rise will greatly redistribute global human population through displacement and migration. Sudden, large-scale displacement is extremely disruptive to society both for migrants and host communities, and there is a great scientific and policy need to anticipate where, when and how this could happen around sea level rise. We can meet these needs by examining how long-term coastal inundation of settlements has already occurred. Using two global geospatial data sets, the Global Human Settlement Layer and the Global Surface Water Layer, we examine the global spatial concentration of settlement inundation that occurred between 1990 and 2015. We focus on the eight sea level rise hotspots identified in Clark et al (2016), which include Bangladesh, Mekong Delta, Indonesia, Japan, Nile Delta, Philippines, and the US Mid-Atlantic and Gulf of Mexico, and examine areas of convergence between settlement loss density and negative population change. This analysis reveals specific areas of concern within vulnerable countries, and forms the basis for focused investigations of the long-term impact of coastal inundation on various migration systems. This analysis shows us how long-term sets of satellite derived data on human population can help anticipate how sea level rise will alter future patterns of human settlement and migration into the 21st century and beyond.

Fingerprinting sea-level variations in response to continental ice loss: a benchmark exercise

NASA Astrophysics Data System (ADS)

Barletta, Valentina R.; Spada, Giorgio; Riva, Riccardo E. M.; James, Thomas S.; Simon, Karen M.; van der Wal, Wouter; Martinec, Zdenek; Klemann, Volker; Olsson, Per-Anders; Hagedoorn, Jan; Stocchi, Paolo; Vermeersen, Bert

2013-04-01

Understanding the response of the Earth to the waxing and waning ice sheets is crucial in various contexts, ranging from the interpretation of modern satellite geodetic measurements to the projections of future sea level trends in response to climate change. All the processes accompanying Glacial Isostatic Adjustment (GIA) can be described solving the so-called Sea Level Equation (SLE), an integral equation that accounts for the interactions between the ice sheets, the solid Earth, and the oceans. Modern approaches to the SLE are based on various techniques that range from purely analytical formulations to fully numerical methods. Here we present the results of a benchmark exercise of independently developed codes designed to solve the SLE. The study involves predictions of current sea level changes due to present-day ice mass loss. In spite of the differences in the methods employed, the comparison shows that a significant number of GIA modellers can reproduce their sea-level computations within 2% for well defined, large-scale present-day ice mass changes. Smaller and more detailed loads need further and dedicated benchmarking and high resolution computation. This study shows how the details of the implementation and the inputs specifications are an important, and often underappreciated, aspect. Hence this represents a step toward the assessment of reliability of sea level projections obtained with benchmarked SLE codes.

Created mangrove wetlands store belowground carbon and surface elevation change enables them to adjust to sea-level rise.

PubMed

Krauss, Ken W; Cormier, Nicole; Osland, Michael J; Kirwan, Matthew L; Stagg, Camille L; Nestlerode, Janet A; Russell, Marc J; From, Andrew S; Spivak, Amanda C; Dantin, Darrin D; Harvey, James E; Almario, Alejandro E

2017-04-21

Mangrove wetlands provide ecosystem services for millions of people, most prominently by providing storm protection, food and fodder. Mangrove wetlands are also valuable ecosystems for promoting carbon (C) sequestration and storage. However, loss of mangrove wetlands and these ecosystem services are a global concern, prompting the restoration and creation of mangrove wetlands as a potential solution. Here, we investigate soil surface elevation change, and its components, in created mangrove wetlands over a 25 year developmental gradient. All created mangrove wetlands were exceeding current relative sea-level rise rates (2.6 mm yr -1 ), with surface elevation change of 4.2-11.0 mm yr -1 compared with 1.5-7.2 mm yr -1 for nearby reference mangroves. While mangrove wetlands store C persistently in roots/soils, storage capacity is most valuable if maintained with future sea-level rise. Through empirical modeling, we discovered that properly designed creation projects may not only yield enhanced C storage, but also can facilitate wetland persistence perennially under current rates of sea-level rise and, for most sites, for over a century with projected medium accelerations in sea-level rise (IPCC RCP 6.0). Only the fastest projected accelerations in sea-level rise (IPCC RCP 8.5) led to widespread submergence and potential loss of stored C for created mangrove wetlands before 2100.

Created mangrove wetlands store belowground carbon and surface elevation change enables them to adjust to sea-level rise

USGS Publications Warehouse

Krauss, Ken W.; Cormier, Nicole; Osland, Michael J.; Kirwan, Matthew L.; Stagg, Camille L.; Nestlerode, Janet A.; Russell, Marc J.; From, Andrew; Spivak, Amanda C.; Dantin, Darrin D.; Harvey, James E.; Almario, Alejandro E.

2017-01-01

Mangrove wetlands provide ecosystem services for millions of people, most prominently by providing storm protection, food and fodder. Mangrove wetlands are also valuable ecosystems for promoting carbon (C) sequestration and storage. However, loss of mangrove wetlands and these ecosystem services are a global concern, prompting the restoration and creation of mangrove wetlands as a potential solution. Here, we investigate soil surface elevation change, and its components, in created mangrove wetlands over a 25 year developmental gradient. All created mangrove wetlands were exceeding current relative sea-level rise rates (2.6 mm yr−1), with surface elevation change of 4.2–11.0 mm yr−1 compared with 1.5–7.2 mm yr−1 for nearby reference mangroves. While mangrove wetlands store C persistently in roots/soils, storage capacity is most valuable if maintained with future sea-level rise. Through empirical modeling, we discovered that properly designed creation projects may not only yield enhanced C storage, but also can facilitate wetland persistence perennially under current rates of sea-level rise and, for most sites, for over a century with projected medium accelerations in sea-level rise (IPCC RCP 6.0). Only the fastest projected accelerations in sea-level rise (IPCC RCP 8.5) led to widespread submergence and potential loss of stored C for created mangrove wetlands before 2100.

Coping with Higher Sea Levels and Increased Coastal Flooding in New York City. Chapter 13

NASA Technical Reports Server (NTRS)

Gornitz, Vivien; Horton, Radley; Bader, Daniel A.; Orton, Philip; Rosenzweig, Cynthia

2017-01-01

The 837 km New York City shoreline is lined by significant economic assets and dense population vulnerable to sea level rise and coastal flooding. After Hurricane Sandy in 2012, New York City developed a comprehensive plan to mitigate future climate risks, drawing upon the scientific expertise of the New York City Panel on Climate Change (NPCC), a special advisory group comprised of university and private-sector experts. This paper highlights current NPCC findings regarding sea level rise and coastal flooding, with some of the City's ongoing and planned responses. Twentieth century sea level rise in New York City (2.8 cm/decade) exceeded the global average (1.7 cm/decade), underscoring the enhanced regional risk to coastal hazards. NPCC (2015) projects future sea level rise at the Battery of 28 - 53 cm by the 2050s and 46 - 99 cm by the 2080s, relative to 2000 - 2004 (mid-range, 25th - 75th percentile). High-end SLR estimates (90th percentile) reach 76 cm by the 2050s, and 1.9 m by 2100. Combining these projections with updated FEMA flood return period curves, assuming static flood dynamics and storm behavior, flood heights for the 100-year storm (excluding waves) attain 3.9-4.5 m (mid-range), relative to the NAVD88 tidal datum, and 4.9 m (high end) by the 2080s, up from 3.4 m in the 2000s. Flood heights with a 1% annual chance of occurrence in the 2000s increase to 2.0 - 5.4% (mid-range) and 12.7% per year (high-end), by the 2080s. Guided by NPCC (2013, 2015) findings, New York City has embarked on a suite of initiatives to strengthen coastal defenses, employing various approaches tailored to specific neighborhood needs. NPCC continues its collaboration with the city to investigate vulnerability to extreme climate events, including heat waves, inland floods and coastal storms. Current research entails higher-resolution neighborhood-level coastal flood mapping, changes in storm characteristics, surge height interactions with sea level rise, and stronger engagement with stakeholders and community-based organizations.

Sensitivity analysis of sea level rise contribution depending on external forcing: A case study of Victoria Land, East Antarctica.

NASA Astrophysics Data System (ADS)

Park, I. W.; Lee, S. H.; Lee, W. S.; Lee, C. K.; Lee, K. K.

2017-12-01

As global mean temperature increases, it affects increase in polar glacier melt and thermal expansion of sea, which contributed to global sea level rise. Unlike large sea level rise contributors in Western Antarctica (e. g. Pine island glacier, Thwaites glacier), glaciers in East Antarctica shows relatively stable and slow ice velocity. However, recent calving events related to increase of supraglacier lake in Nansen ice shelf arouse the questions in regards to future evolution of ice dynamics at Victoria Land, East Antarctica. Here, using Ice Sheet System Model (ISSM), a series of numerical simulations were carried out to investigate ice dynamics evolution (grounding line migration, ice velocity) and sea level rise contribution in response to external forcing conditions (surface mass balance, floating ice melting rate, and ice front retreat). In this study, we used control method to set ice dynamic properties (ice rigidity and friction coefficient) with shallow shelf approximation model and check each external forcing conditions contributing to sea level change. Before 50-year transient simulations were conducted based on changing surface mass balance, floating ice melting rate, and ice front retreat of Drygalski ice tongue and Nansen ice shelf, relaxation was performed for 10 years to reduce non-physical undulation and it was used as initial condition. The simulation results showed that sea level rise contribution were expected to be much less compared to other fast glaciers. Floating ice melting rate was most sensitive parameter to sea level rise, while ice front retreat of Drygalski tongue was negligible. The regional model will be further updated utilizing ice radar topography and measured floating ice melting rate.

An Earth's Future Special Collection: Impacts of the coastal dynamics of sea level rise on low-gradient coastal landscapes

NASA Astrophysics Data System (ADS)

Kidwell, David M.; Dietrich, J. Casey; Hagen, Scott C.; Medeiros, Stephen C.

2017-01-01

Rising sea level represents a significant threat to coastal communities and ecosystems, including altered habitats and increased vulnerability to coastal storms and recurrent inundation. This threat is exemplified in the northern Gulf of Mexico, where low topography, marshes, and a prevalence of tropical storms have resulted in extensive coastal impacts. The ability to facilitate adaptation and mitigation measures relies, in part, on the development of robust predictive capabilities that incorporate complex biological processes with physical dynamics. Initiated in 2010, the 6-year Ecological Effects of Sea Level Rise—Northern Gulf of Mexico project applied a transdisciplinary science approach to develop a suite of integrated modeling platforms informed by empirical data that are capable of evaluating a range of climate change scenarios. This special issue highlights resultant integrated models focused on tidal hydrodynamics, shoreline morphology, oyster ecology, coastal wetland vulnerability, and storm surges that demonstrate the need for dynamic models to incorporate feedbacks among physical and biological processes in assessments of sea level rise effects on coastal systems. Effects are projected to be significant, spatially variable and nonlinear relative to sea level rise rates. Scenarios of higher sea level rise rates are projected to exceed thresholds of wetland sustainability, and many regions will experience enhanced storm surges. Influenced by an extensive collaborative stakeholder engagement process, these assessments on the coastal dynamics of sea level rise provide a strong foundation for resilience measures in the northern Gulf of Mexico and a transferable approach for application to other coastal regions throughout the world.

Sea Level Rise in the 21st Century: Will projections ever become reliable?

NASA Astrophysics Data System (ADS)

Willis, J. K.

2014-12-01

Global sea level rise has the potential to become one of the most costly and least well predicted impacts of human caused climate change. Unlike global surface temperature, the spread of possible scenarios (as little as 1 foot and as much as 6 feet by 2100) is not due to uncertainty about future rates of greenhouse gas emissions, but rather by a fundamental lack of knowledge about how the major ice sheets will behave in a warming climate. Clearly improved projections of sea level rise should become a major research priority in the next decade. At present, controversial techniques based on comparison with historical analogs and rates of recent warming and sea level rise are often used to create projections for the 21st Century. However, many in the scientific community feel that reliable projections must be based on a sound knowledge of the physics governing sea level rise, and particularly ice sheet behavior. In particular, large portions of the West Antarctic Ice Sheet and parts of the Greenland Ice Sheet rest on solid earth that sits below sea level. These regions may be threatened, not by atmospheric warming or changes in precipitation, but rather by direct forcing from the ocean. Fledgling efforts to understand these ocean ice interactions are already underway, as are efforts to make improved models of ice sheet behavior. However a great deal of work is still needed before widely accepted projections of sea level rise become a reality. This paper will highlight the hurdles to making such projections today and suggest ways forward in this critical area of research.

The Immediacy of Arctic Change: New 2016-17 Extremes

NASA Astrophysics Data System (ADS)

Overland, J. E.; Kattsov, V.; Olsen, M. S.; Walsh, J. E.

2017-12-01

Additional recent observations add increased certainty to cryospheric Arctic changes, and trends are very likely to continue past mid-century. Observed and projected Arctic changes are large compared with those at mid-latitude, driven by greenhouse gas (GHG) increase and Arctic feedbacks. Sea ice has undergone a regime shift from mostly multi-year to first-year sea ice, and summer sea ice is likely to be esentially gone within the next few decades. Spring snow cover is decreasing, and Arctic greening is increasing, although somewhat variable. There are potential emerging impacts of Arctic change on mid-latitude weather and sea level rise. Model assessments under different future GHG concentration scenarios show that stabilizing global temperatures near 2° C compliant with Paris agreement could slow, but not halt further major changes in the Arctic before mid- 21st century; foreseeable Arctic temperature changes are 4-5° C for fall/winter by 2040-2050. Substantial and immediate mitigation reductions in GHG emissions (at least at the level of the RCP 4.5 emission scenario) should reduce the risk of further change for most cryospheric components after mid-century, and reduce the likelyhood of potential runaway loss of ice sheets and glaciers and their impact on sea level rise. Extreme winter 2016 Arctic temperatures and a large winter 2017 sea ice deficit demonstrate contemporary climate states outside the envelope of previous experience. While there is confidence in the sign of Arctic changes, recent observations increase uncertainty in projecting the rate for future real world scenarios. Do events return to mean conditions, represent irreversible changes, or contribute to accelerating trends beyond those provided by climate models? Such questions highlight the need for improved quantitative prediction of the cryosphere and its global impacts, crucial for adaptation actions and risk management at local to global scales.

Modeling vegetation community responses to sea-level rise on Barrier Island systems: A case study on the Cape Canaveral Barrier Island complex, Florida, USA

PubMed Central

Foster, Tammy E.; Stolen, Eric D.; Hall, Carlton R.; Schaub, Ronald; Duncan, Brean W.; Hunt, Danny K.; Drese, John H.

2017-01-01

Society needs information about how vegetation communities in coastal regions will be impacted by hydrologic changes associated with climate change, particularly sea level rise. Due to anthropogenic influences which have significantly decreased natural coastal vegetation communities, it is important for us to understand how remaining natural communities will respond to sea level rise. The Cape Canaveral Barrier Island complex (CCBIC) on the east central coast of Florida is within one of the most biologically diverse estuarine systems in North America and has the largest number of threatened and endangered species on federal property in the contiguous United States. The high level of biodiversity is susceptible to sea level rise. Our objective was to model how vegetation communities along a gradient ranging from hydric to upland xeric on CCBIC will respond to three sea level rise scenarios (0.2 m, 0.4 m, and 1.2 m). We used a probabilistic model of the current relationship between elevation and vegetation community to determine the impact sea level rise would have on these communities. Our model correctly predicted the current proportions of vegetation communities on CCBIC based on elevation. Under all sea level rise scenarios the model predicted decreases in mesic and xeric communities, with the greatest losses occurring in the most xeric communities. Increases in total area of salt marsh were predicted with a 0.2 and 0.4 m rise in sea level. With a 1.2 m rise in sea level approximately half of CCBIC’s land area was predicted to transition to open water. On the remaining land, the proportions of most of the vegetation communities were predicted to remain similar to that of current proportions, but there was a decrease in proportion of the most xeric community (oak scrub) and an increase in the most hydric community (salt marsh). Our approach provides a first approximation of the impacts of sea level rise on terrestrial vegetation communities, including important xeric upland communities, as a foundation for management decisions and future modeling. PMID:28796807

Kiel Canal: Past and future threats for shipping resulting from precipitation, wind surge and sea level rise

NASA Astrophysics Data System (ADS)

Ganske, Anette; Hüttl-Kabus, Sabine; Möller, Jens; Schade, Nils; Heinrich, Hartmut; Tinz, Birger

2017-04-01

The Kiel Canal is the most frequented artificial waterway in the world. It connects the North Sea and the Hamburg Harbor with the Baltic Sea and has a length of about 100 km. The Canal receives its water from the upper catchment of the river Eider. Discharge from the Canal towards the North Sea is via the sluices at Brunsbüttel (90%) into river Elbe and into the Baltic Sea via the sluices at Kiel-Holtenau. A risk of closure of the Canal occurs when high precipitation in the catchment meets high water levels in the river Elbe and/or the Baltic preventing the discharge of excess Canal water. Future sea level rise jointly with other effects such as possibly increasing wind surge and precipitation will close the gap between the inner and outer water levels, so that someday the outside levels will surmount the inner one. The German Federal Ministry of Transport and Digital Infrastructure (BMVI) tasked its internal Network of Experts to run a case study on the evolution of critical water levels in order to estimate risks and vulnerabilities for adaptation measures. First step of the investigation is a search for factors or combination of factors responsible for closures in the past. Candidates are factors such as higher water levels at low tides, high precipitation events on land, soil moisture and human factors like preventive water management measures. Second step will be the search for the natural criteria in climate projections. Here we report on the results of the first step of the case study with a focus on the exit towards the North Sea. There, discharge is possible only during low tide. Presently still sufficient difference in height exists between the levels in the Canal and the river Elbe allowing for a free flow of excess Canal water. Shipping is ceased when levels in the Canal surpass safety limits due to high precipitation events in the catchment jointly with high outer water levels. We used atmospheric data from ERA-Interim reanalysis instead of gauge data for reconstructing the history in order to provide metrics that in the second step can be searched in Atmosphere Regional Climate Model runs. Water levels at Brunsbüttel were determined with hourly resolution using atmospheric conditions and astronomical tide. Ocean Model results were and will be excluded because of the small number of runs with astronomical tides and sufficient resolution. Past inflow from the tributary rivers into the Canal was simulated via antecedent and event precipitation derived from the REGNIE data set. Finally, the potential of critical situations in the past was calculated by combining both results and compared their occurrences with the recordings of the responsible waterway authority. In the second step we will analyze the proxies elaborated in step one in regional climate projections and combine them with expected changes of the sea levels in the North and Baltic Seas.

Global sea-level change during the next 10,000 years: the end of an icehouse?

NASA Astrophysics Data System (ADS)

Van Breedam, Jonas; Huybrechts, Philippe; Goelzer, Heiko; Loutre, Marie-France; Fichefet, Thierry

2015-04-01

Because of the long life-time of atmospheric CO2, any realized future warming is likely to persist for many centuries to millennia. As a consequence, sea-level rise will continue on a multi-millennial timescale, especially from the slower components such as oceanic thermal expansion and above all, from melting of the Greenland and Antarctic ice sheets. The two polar ice sheets have the potential to produce a global eustatic sea-level rise of about 65 m, at least an order of magnitude larger than thermal expansion under extreme forcing scenarios. Other components contributing to sea-level change are the melting of glaciers and ice caps and haline contraction of the ocean from fresh water delivery from land ice, but are less important. We have made projections of future sea-level rise over the next 10,000 years with the Earth System Model of Intermediate Complexity LOVECLIM, which includes high resolution models of the Greenland and Antarctic ice sheets. Four different model parameter sets are considered to explore the model uncertainty. The climate forcing is based on prolonged Radiative Concentration Pathway (RCP) scenarios with an assumed exponential falloff for carbon dioxide concentrations according to global carbon cycle simulations. Six different forcing scenarios are constructed where the highest scenario includes a positive feedback due to the destabilization of methane hydrates and the subsequent emission of methane. By far the largest contribution in the global sea-level projections arises from the polar ice sheets. For the Greenland ice sheet, the ablation is larger than the accumulation for all forcing scenarios shortly after the start of the experiments. The ice sheet continuously melts and nearly disappears in all cases. The Antarctic ice sheet grows during the first decades under low to intermediate forcing scenarios due to increased accumulation. However, the spread between the different scenarios is very large. Under the highest prolonged RCP scenario (and in case methane hydrate starts to destabilize), the model uncertainty does not exclude melting of the entire Antarctic ice sheet after 10,000 years. This would mark the end of the present icehouse, which has existed for about 34 Myr, and would raise global sea-level by up to 70 m from all contributions combined.

Dynamic and Regression Modeling of Ocean Variability in the Tide-Gauge Record at Seasonal and Longer Periods

NASA Technical Reports Server (NTRS)

Hill, Emma M.; Ponte, Rui M.; Davis, James L.

2007-01-01

Comparison of monthly mean tide-gauge time series to corresponding model time series based on a static inverted barometer (IB) for pressure-driven fluctuations and a ocean general circulation model (OM) reveals that the combined model successfully reproduces seasonal and interannual changes in relative sea level at many stations. Removal of the OM and IB from the tide-gauge record produces residual time series with a mean global variance reduction of 53%. The OM is mis-scaled for certain regions, and 68% of the residual time series contain a significant seasonal variability after removal of the OM and IB from the tide-gauge data. Including OM admittance parameters and seasonal coefficients in a regression model for each station, with IB also removed, produces residual time series with mean global variance reduction of 71%. Examination of the regional improvement in variance caused by scaling the OM, including seasonal terms, or both, indicates weakness in the model at predicting sea-level variation for constricted ocean regions. The model is particularly effective at reproducing sea-level variation for stations in North America, Europe, and Japan. The RMS residual for many stations in these areas is 25-35 mm. The production of "cleaner" tide-gauge time series, with oceanographic variability removed, is important for future analysis of nonsecular and regionally differing sea-level variations. Understanding the ocean model's strengths and weaknesses will allow for future improvements of the model.

Uncertainty In Greenhouse Gas Emissions On Carbon Sequestration In Coastal and Freshwater Wetlands of the Mississippi River Delta: A Subsiding Coastline as a Proxy for Future Global Sea Level

NASA Astrophysics Data System (ADS)

White, J. R.; DeLaune, R. D.; Roy, E. D.; Corstanje, R.

2014-12-01

The highly visible phenomenon of wetland loss in coastal Louisiana (LA) is examined through the prism of carbon accumulation, wetland loss and greenhouse gas (GHG) emissions. The Mississippi River Deltaic region experiences higher relative sea level rise due to coupled subsidence and eustatic sea level rise allowing this region to serve as a proxy for future projected golbal sea level rise. Carbon storage or sequestration in rapidly subsiding LA coastal marsh soils is based on vertical marsh accretion and areal change data. While coastal marshes sequester significant amount of carbon through vertical accretion, large amounts of carbon, previously sequested in the soil profile is lost through annual deterioration of these coastal marshes as well as through GHG emissions. Efforts are underway in Louisiana to access the carbon credit market in order to provide significant funding for coastal restoration projects. However, there is very large uncertainty on GHG emission rates related to both marsh type and temporal (daily and seasonal) effects. Very little data currently exists which addresses this uncertainty which can significantly affect the carbon credit value of a particular wetland system. We provide an analysis of GHG emission rates for coastal freshwater, brackish and and salt marshes compared to the net soil carbon sequestration rate. Results demonstrate that there is very high uncertainty on GHG emissions which can substantially alter the carbon credit value of a particular wetland system.

Uncovering the Anthropogenic Sea Level Change using an Improved Sea Level Reconstruction for the Indian Ocean

NASA Astrophysics Data System (ADS)

Kumar, P.; Hamlington, B.; Thompson, P. R.; Han, W.

2016-12-01

Despite having some of the world's most densely populated and vulnerable coastal regions, sea level (SL) variability in the Indian Ocean (IO) has received considerably less attention than the Pacific Ocean. Differentiating the internal variability from the long-term trend in global mean sea level (GMSL) at decadal time-scales is vital for planning and mitigation efforts in the IO region. Understanding the dynamics of internal and anthropogenic SL change is essential for understanding the dynamic pathways that link the IO basin to terrestrial climates world-wide. With a sparse pre-satellite observational record of the IO, the Indo-Pacific internal climate variability is difficult to represent accurately. However, an improved representation of pre-satellite SL variability can be achieved by using a multivariate reconstruction technique. By using cyclostationary empirical orthogonal functions (CSEOFs) that can capture time-varying spatial patterns, gaps in the historical record when observations are sparse are filled using spatial relationships from time periods when the observational network is dense. This reconstruction method combines SL data and sea surface temperature (SST) to create a SL reconstruction that spans a period from 1900 to present, long enough to study climate signals over interannual to decadal time scales. This study aims at estimating the component of SL rise that relates to anthropogenic forcing by identifying and removing the fraction related to internal variability. An improved understanding of how the internal climate variability can affect the IO SL trend and variability, will provide an insight into the future SL changes. It is also important to study links between SL and climate variability in the past to understand how SL will respond to similar climatic events in the future and if this response will be influenced by the changing climate.

Future Nuisance Flooding at Boston Caused by Astronomical Tides Alone

NASA Technical Reports Server (NTRS)

Ray, Richard D.; Foster, Grant

2016-01-01

Sea level rise necessarily triggers more occurrences of minor, or nuisance, flooding events along coastlines, a fact well documented in recent studies. At some locations nuisance flooding can be brought about merely by high spring tides, independent of storms, winds, or other atmospheric conditions. Analysis of observed water levels at Boston indicates that tidal flooding began to occur there in 2011 and will become more frequent in subsequent years. A compilation of all predicted nuisance-flooding events, induced by astronomical tides alone, is presented through year 2050. The accuracy of the tide prediction is improved when several unusual properties of Gulf of Maine tides, including secular changes, are properly accounted for. Future mean sea-level rise at Boston cannot be predicted with comparable confidence, so two very different climate scenarios are adopted; both predict a large increase in the frequency and the magnitude of tidal flooding events.

Extreme Sea Level Rise Event Linked to 2009-10 AMOC Downturn

NASA Astrophysics Data System (ADS)

Yin, J.

2016-02-01

The coastal sea levels along the Northeast Coast of North America show significant year-to-year fluctuations in a general upward trend. Our analysis of long-term tide gauge records along the North American east coast identified an extreme sea-level rise (SLR) event during 2009-2010. Within this relatively brief two-year period, coastal sea levels north of New York City jumped by 100 mm. This magnitude of inter-annual SLR is unprecedented in the century-long tide gauge records, with statistical methods suggesting that it was a 1-in-850 year event. We show that this extreme SLR event was a combined effect of two physical factors. First, it was partly due to an observed 30% downturn of the Atlantic meridional overturning circulation (AMOC) during 2009-2010. This AMOC slowdown caused a significant decline of the dynamic sea level gradient across the Gulf Stream and North Atlantic Current, thereby imparting a rise in coastal sea level. The second contributing factor to the extreme SLR event was due to a significant negative North Atlantic Oscillation (NAO) index. The associated easterly or northeasterly wind anomalies acted to push ocean waters towards the Northeast Coast through the Ekman transport, resulting in further rise in coastal sea levels. Sea level pressure anomalies also contributed to the extreme SLR event through the inverse barometer effect. To project future extreme sea levels along the east coast of North America during the 21st century, we make use of a suite of climate/Earth system models developed at GFDL and other modeling centers. These models included typical CMIP5-class models, as well as the newer climate models GFDL CM2.5 and CM2.6 with eddying oceans. In response to the increase in greenhouse-gas concentrations, each of these models show a reduction in the AMOC. Given the observed connection between AMOC reduction and extreme coastal sea levels, the models thus project an increase in extreme SLR frequency on interannual time scales along the Northeast Coast of North America.

Projected status of the Pacific walrus (Odobenus rosmarus divergens) in the twenty-first century

USGS Publications Warehouse

Jay, Chadwick V.; Marcot, Bruce G.; Douglas, David C.

2011-01-01

Extensive and rapid losses of sea ice in the Arctic have raised conservation concerns for the Pacific walrus (Odobenus rosmarus divergens), a large pinniped inhabiting arctic and subarctic continental shelf waters of the Chukchi and Bering seas. We developed a Bayesian network model to integrate potential effects of changing environmental conditions and anthropogenic stressors on the future status of the Pacific walrus population at four periods through the twenty-first century. The model framework allowed for inclusion of various sources and levels of knowledge, and representation of structural and parameter uncertainties. Walrus outcome probabilities through the century reflected a clear trend of worsening conditions for the subspecies. From the current observation period to the end of century, the greatest change in walrus outcome probabilities was a progressive decrease in the outcome state of robust and a concomitant increase in the outcome state of vulnerable. The probabilities of rare and extirpated states each progressively increased but remained <10% through the end of the century. The summed probabilities of vulnerable, rare, and extirpated (P(v,r,e)) increased from a current level of 10% in 2004 to 22% by 2050 and 40% by 2095. The degree of uncertainty in walrus outcomes increased monotonically over future periods. In the model, sea ice habitat (particularly for summer/fall) and harvest levels had the greatest influence on future population outcomes. Other potential stressors had much smaller influences on walrus outcomes, mostly because of uncertainty in their future states and our current poor understanding of their mechanistic influence on walrus abundance.

Adaptation to Sea Level Rise in Coastal Units of the National Park Service (Invited)

NASA Astrophysics Data System (ADS)

Beavers, R. L.

2010-12-01

83 National Park Service (NPS) units contain nearly 12,000 miles of coastal, estuarine and Great Lakes shoreline and their associated resources. Iconic natural features exist along active shorelines in NPS units, including, e.g., Cape Cod, Padre Island, Hawaii Volcanoes, and the Everglades. Iconic cultural resources managed by NPS include the Cape Hatteras Lighthouse, Fort Sumter, the Golden Gate, and heiaus and fish traps along the coast of Hawaii. Impacts anticipated from sea level rise include inundation and flooding of beaches and low lying marshes, shoreline erosion of coastal areas, and saltwater intrusion into the water table. These impacts and other coastal hazards will threaten park beaches, marshes, and other resources and values; alter the viability of coastal roads; and require the NPS to re-evaluate the financial, safety, and environmental implications of maintaining current projects and implementing future projects in ocean and coastal parks in the context of sea level rise. Coastal erosion will increase as sea levels rise. Barrier islands along the coast of Louisiana and North Carolina may have already passed the threshold for maintaining island integrity in any scenario of sea level rise (U.S. Climate Change Science Program Synthesis and Assessment Program Report 4.1). Consequently, sea level rise is expected to hasten the disappearance of historic coastal villages, coastal wetlands, forests, and beaches, and threaten coastal roads, homes, and businesses. While sea level is rising in most coastal parks, some parks are experiencing lower water levels due to isostatic rebound and lower lake levels. NPS funded a Coastal Vulnerability Project to evaluate the physical and geologic factors affecting 25 coastal parks. The USGS Open File Reports for each park are available at http://woodshole.er.usgs.gov/project-pages/. These reports were designed to inform park planning efforts. NPS conducted a Storm Vulnerability Project to provide ocean and coastal National Park units with Natural, Cultural and Historic Resource-based data products and management documents that will aid the parks in better managing aspects of storm-preparedness and post-storm response and recovery. These results as well as specific efforts to address vulnerability of NPS facilities and natural and cultural resources to sea level rise will be discussed. NPS is also coordinating with NOAA to fill a new position for coastal adaptation and apply the information learned from research, vulnerability studies, and work with partners to develop adaptation strategies for coastal and ocean parks. To adapt to sea level rise, NPS will develop strong policies, guidance, and interpretive materials to help parks take actions that will increase the resilience of ocean and coastal park biological and geologic resources, reduce inappropriate stressors and greenhouse gas emissions in ocean and coastal parks, and educate the public about the need for comprehensive, swift and effective measures that will help the NPS conserve ocean and coastal park resources for future generations.

Parcel-scale urban coastal flood mapping: Leveraging the multi-scale CoSMoS model for coastal flood forecasting

NASA Astrophysics Data System (ADS)

Gallien, T.; Barnard, P. L.; Sanders, B. F.

2011-12-01

California coastal sea levels are projected to rise 1-1.4 meters in the next century and evidence suggests mean tidal range, and consequently, mean high water (MHW) is increasing along portions of Southern California Bight. Furthermore, emerging research indicates wind stress patterns associated with the Pacific Decadal Oscillation (PDO) have suppressed sea level rise rates along the West Coast since 1980, and a reversal in this pattern would result in the resumption of regional sea level rise rates equivalent to or exceeding global mean sea level rise rates, thereby enhancing coastal flooding. Newport Beach is a highly developed, densely populated lowland along the Southern California coast currently subject to episodic flooding from coincident high tides and waves, and the frequency and intensity of flooding is expected to increase with projected future sea levels. Adaptation to elevated sea levels will require flood mapping and forecasting tools that are sensitive to the dominant factors affecting flooding including extreme high tides, waves and flood control infrastructure. Considerable effort has been focused on the development of nowcast and forecast systems including Scripps Institute of Oceanography's Coastal Data Information Program (CDIP) and the USGS Multi-hazard model, the Southern California Coastal Storm Modeling System (CoSMoS). However, fine scale local embayment dynamics and overtopping flows are needed to map unsteady flooding effects in coastal lowlands protected by dunes, levees and seawalls. Here, a recently developed two dimensional Godunov non-linear shallow water solver is coupled to water level and wave forecasts from the CoSMoS model to investigate the roles of tides, waves, sea level changes and flood control infrastructure in accurate flood mapping and forecasting. The results of this study highlight the important roles of topographic data, embayment hydrodynamics, water level uncertainties and critical flood processes required for meaningful prediction of sea level rise impacts and coastal flood forecasting.

Boldness in a deep sea hermit crab to simulated tactile predator attacks is unaffected by ocean acidification

NASA Astrophysics Data System (ADS)

Kim, Tae Won; Barry, James P.

2016-09-01

Despite rapidly growing interest in the effects of ocean acidification on marine animals, the ability of deep-sea animals to acclimate or adapt to reduced pH conditions has received little attention. Deep-sea species are generally thought to be less tolerant of environmental variation than shallow-living species because they inhabit relatively stable conditions for nearly all environmental parameters. To explore whether deep-sea hermit crabs ( Pagurus tanneri) can acclimate to ocean acidification over several weeks, we compared behavioral "boldness," measured as time taken to re-emerge from shells after a simulated predatory attack by a toy octopus, under ambient (pH ˜7.6) and expected future (pH ˜7.1) conditions. The boldness measure for crab behavioral responses did not differ between different pH treatments, suggesting that future deep-sea acidification would not influence anti-predatory behavior. However, we did not examine the effects of olfactory cues released by predators that may affect hermit crab behavior and could be influenced by changes in the ocean carbonate system driven by increasing CO2 levels.

Increasing Resilience Through Engagement In Sea Level Rise Community Science Initiatives.

NASA Astrophysics Data System (ADS)

Chilton, L. A.; Rindge, H.

2017-12-01

Science literate and engaged members of the public, including students, are critical to building climate resilient communities. USC Sea Grant facilitates programs that work to build and strengthen these connections. The Urban Tides Community Science Initiative (Urban Tides) and the Youth Exploring Sea Level Rise Science Program (YESS) engage communities across the boundaries of public engagement, K-12 education, and informal education. YESS is an experiential sea level rise education program that combines classroom learning, field investigations and public presentations. Students explore sea level rise using a new curricula, collect their own data on sea level rise, develop communication products, and present their findings to city governments, researchers, and others. Urban Tides engages community members, informal education centers, K-12 students, and local government leaders in a citizen science program photo- documenting extreme high tides, erosion and coastal flooding in Southern California. Images provide critical information to help calibrate scientific models used to identify locations vulnerable to damage from future sea level rise. These tools and information enable community leaders and local governments to set priorities, guidelines, and update policies as they plan strategies that will help the region adapt. The program includes a mobile app for data collection, an open database to view photos, a lesson plan, and community beach walks. Urban Tides has led to an increase in data and data-gathering capacity for regional scientists, an increase in public participation in science, and an increase in ocean and climate literacy among initiative participants. Both of these programs bring informed and diverse voices into the discussion of how to adapt and build climate resilient communities. USC Sea Grant will share impacts and lessons learned from these two unique programs.

An Intensive Observation of Calving at Helheim Glacier, East Greenland

NASA Technical Reports Server (NTRS)

Holland, David M.; Voytenko, Denis; Christianson, Knut; Dixon, Timothy H.; Mei, M. Jeffrey; Parizek, Byron R.; Vankova, Irena; Walker, Ryan T.; Walter, Jacob I.; Nicholls, Keith;

Ice-sheet contributions to future sea-level change.

PubMed

Gregory, J M; Huybrechts, P

2006-07-15

Accurate simulation of ice-sheet surface mass balance requires higher spatial resolution than is afforded by typical atmosphere-ocean general circulation models (AOGCMs), owing, in particular, to the need to resolve the narrow and steep margins where the majority of precipitation and ablation occurs. We have developed a method for calculating mass-balance changes by combining ice-sheet average time-series from AOGCM projections for future centuries, both with information from high-resolution climate models run for short periods and with a 20km ice-sheet mass-balance model. Antarctica contributes negatively to sea level on account of increased accumulation, while Greenland contributes positively because ablation increases more rapidly. The uncertainty in the results is about 20% for Antarctica and 35% for Greenland. Changes in ice-sheet topography and dynamics are not included, but we discuss their possible effects. For an annual- and area-average warming exceeding 4.5+/-0.9K in Greenland and 3.1+/-0.8K in the global average, the net surface mass balance of the Greenland ice sheet becomes negative, in which case it is likely that the ice sheet would eventually be eliminated, raising global-average sea level by 7m.

Mesoscale resolution capability of altimetry: Present and future

NASA Astrophysics Data System (ADS)

Dufau, Claire; Orsztynowicz, Marion; Dibarboure, Gérald; Morrow, Rosemary; Le Traon, Pierre-Yves

2016-07-01

Wavenumber spectra of along-track Sea Surface Height from the most recent satellite radar altimetry missions [Jason-2, Cryosat-2, and SARAL/Altika) are used to determine the size of ocean dynamical features observable with the present altimetry constellation. A global analysis of the along-track 1-D mesoscale resolution capability of the present-day altimeter missions is proposed, based on a joint analysis of the spectral slopes in the mesoscale band and the error levels observed for horizontal wavelengths lower than 20km. The global sea level spectral slope distribution provided by Xu and Fu with Jason-1 data is revisited with more recent altimeter missions, and maps of altimeter error levels are provided and discussed for each mission. Seasonal variations of both spectral slopes and altimeter error levels are also analyzed for Jason-2. SARAL/Altika, with its lower error levels, is shown to detect smaller structures everywhere. All missions show substantial geographical and temporal variations in their mesoscale resolution capabilities, with variations depending mostly on the error level change but also on slight regional changes in the spectral slopes. In western boundary currents where the signal to noise ratio is favorable, the along-track mesoscale resolution is approximately 40 km for SARAL/AltiKa, 45 km for Cryosat-2, and 50 km for Jason-2. Finally, a prediction of the future 2-D mesoscale sea level resolution capability of the Surface Water and Ocean Topography (SWOT) mission is given using a simulated error level.

Assessment of the climate change impacts on fecal coliform contamination in a tidal estuarine system.

PubMed

Liu, Wen-Cheng; Chan, Wen-Ting

2015-12-01

Climate change is one of the key factors affecting the future microbiological water quality in rivers and tidal estuaries. A coupled 3D hydrodynamic and fecal coliform transport model was developed and applied to the Danshuei River estuarine system for predicting the influences of climate change on microbiological water quality. The hydrodynamic and fecal coliform model was validated using observational salinity and fecal coliform distributions. According to the analyses of the statistical error, predictions of the salinity and the fecal coliform concentration from the model simulation quantitatively agreed with the observed data. The validated model was then applied to predict the fecal coliform contamination as a result of climate change, including the change of freshwater discharge and the sea level rise. We found that the reduction of freshwater discharge under climate change scenarios resulted in an increase in the fecal coliform concentration. The sea level rise would decrease fecal coliform distributions because both the water level and the water volume increased. A reduction in freshwater discharge has a negative impact on the fecal coliform concentration, whereas a rising sea level has a positive influence on the fecal coliform contamination. An appropriate strategy for the effective microbiological management in tidal estuaries is required to reveal the persistent trends of climate in the future.

Effect of specific pathways to 1.5°C global warming on the contribution of Greenland to sea level rise

NASA Astrophysics Data System (ADS)

Humbert, A.; Rückamp, M.; Falk, U.; Frieler, K.

2017-12-01

Sea level rise associated with changing climate is expected to pose a major challenge for societies. Here, we estimate the future contribution of the Greenland ice sheet (GrIS) to sea level change in terms of different emission scenarios. We investigate the effect of different pathways of global warming on the dynamics and mass balance of the GrIS with a focus on scenarios in line with limiting global warming to 2.0° or even 1.5° by the end of 2100 (Paris Agreement). We particularly address the issue of peak and decline scenarios temporarily exceeding a given temperature limit. This kind of overshooting might have strong effects on the evolution of the GrIS. Furthermore, we investigate the long-term effects of different levels of climate change to estimate the threshold for stabilizing the GrIS. For modeling the flow dynamics and future evolution of the GrIS, we apply the thermo-mechanical coupled Ice Sheet System Model (ISSM). The model is forced with anomalies for temperature and surface mass balance derived from different GCM data from the CMIP5 RCP2.6 scenario provided from the ISIMIP2b project. In order to obtain these anomalies from the GCM data, a surface energy balance model is applied.

Dasymetric high resolution population distribution estimates for improved decision making, with a case study of sea-level rise vulnerability in Boca Raton, Florida

NASA Astrophysics Data System (ADS)

Ziegler, Hannes Moritz

Planners and managers often rely on coarse population distribution data from the census for addressing various social, economic, and environmental problems. In the analysis of physical vulnerabilities to sea-level rise, census units such as blocks or block groups are coarse relative to the required decision-making application. This study explores the benefits offered from integrating image classification and dasymetric mapping at the household level to provide detailed small area population estimates at the scale of residential buildings. In a case study of Boca Raton, FL, a sea-level rise inundation grid based on mapping methods by NOAA is overlaid on the highly detailed population distribution data to identify vulnerable residences and estimate population displacement. The enhanced spatial detail offered through this method has the potential to better guide targeted strategies for future development, mitigation, and adaptation efforts.

Assessment of extreme hydrological conditions in the Bothnian Bay, Baltic Sea, and the impact of the nuclear power plant "Hanhikivi-1" on the local thermal regime

NASA Astrophysics Data System (ADS)

Dvornikov, Anton Y.; Martyanov, Stanislav D.; Ryabchenko, Vladimir A.; Eremina, Tatjana R.; Isaev, Alexey V.; Sein, Dmitry V.

2017-04-01

The results of the study aimed to assess the influence of future nuclear power plant Hanhikivi-1 upon the local thermal conditions in the Bothnian Bay in the Baltic Sea are presented. A number of experiments with different numerical models were also carried out in order to estimate the extreme hydro-meteorological conditions in the area of the construction. The numerical experiments were fulfilled both with analytically specified external forcing and with real external forcing for 2 years: a cold year (2010) and a warm year (2014). The study has shown that the extreme values of sea level and water temperature and the characteristics of wind waves and sea ice in the vicinity of the future nuclear power plant can be significant and sometimes catastrophic. Permanent release of heat into the marine environment from an operating nuclear power plant will lead to a strong increase in temperature and the disappearance of ice cover within a 2 km vicinity of the station. These effects should be taken into account when assessing local climate changes in the future.

Understanding the Effects of Sea-Level Rise on Coastal Wetlands: The Human Dimension

NASA Astrophysics Data System (ADS)

Reed, Denise

2010-05-01

In the 21st century coastal systems are subject to the pressures of centuries of population growth and resource exploitation. In 2003, in the US approximately 153 million people (53 percent of the population) lived in coastal counties, an increase of 33 million people since 1980 and this is expected to increase by approximately 7 million by the year 2008. Eight of the world's top ten largest cities are located at the coast, 44 % of the world's population (more people than inhabited the entire globe in 1950) live within 150 km of the coast and in 2001 over half the world's population lived within 200 km of a coastline. . Increased population density at the coasts often brings pollution and habitat degradation - decreasing the value of many of the resources that initially attract the coastal development - and it also means the effect of sea-level rise on coastal geomorphic systems must be seen in the context of additional human pressures. For global sea-level debate centers on the magnitude and rate of the rise around most of the world; the exception being those areas still experiencing falling sea-levels due to isostatic rebound. Many coastal island states are clearly vulnerable. While the ‘lurid and misleading maps' of the 1980's used by many to indicate areas to be flooded by rising seas in the future, have been replaced by more considered discussion of the response of coastal dynamics to rising seas there is still considerable debate about the amount of sea-level rise shorelines will experience in the 21st century. For coastal wetlands four main sets of physical factors - fine sediment regime; tidal conditions; coastal configuration; and relative sea-level change - define the geomorphic context for coastal marsh development and survival during the 21st century. Each of these factors is influenced by changes in climate and human alterations to coastal and inshore environments. In turn changes in sediment dynamics are mediated by both physical forcing and biotic factors, and plant growth is an additional factor influencing the survival of more organic marshes. Salt marsh surfaces are frequently considered to be in an equilibrium relationship with local mean sea level but the projection of salt marsh sustainability under future climate scenarios is a complex issue and depends on: the relative importance of organic matter to marsh vertical development; the complexities governing organic matter accumulation during rising sea level; the importance of subsurface processes in determining surface elevation change; and the role of storm events and hydrologic changes in controlling sediment deposition, soil conditions and plant growth. The effects of global change, both climate and human induced, on coastal wetlands will be manifest differently among various geomorphic settings but their vulnerability to global change in the 21st century should be taken seriously by coastal managers and policy-makers alike.

Experiences with GOCE models in SONMICAT-BCN calibration site.

NASA Astrophysics Data System (ADS)

Martinez-Benjamin, J. J.; Termens, A.; Pros, F.

2016-12-01

SONMICAT - the integrated sea level observation system of Catalonia - aims at providing high-quality continous measurements of sea- and land levels at the Catalan coast from tide gauges and from modern geodetic techniques for studies on long-term sea level trends, but also the calibration of satellite altimeters, for instance. This synergy is indeed the only way to get a clear and unambigous picture of what is actually going on at the coast of Catalonia. Actually, there is a gap of sea level data in the coastal area of Catalonia, although several groups have started to do some work. SONMICAT will fill it and, as a goal, will be a regional implementation and densification of the GGOS . In the framework of SONMICAT project, the sea level infrastructure has been improved by providing the harbour of Barcelona with 3 tide gauges and a GPS station nearby. Furthermore, an airborne LiDAR campaign was carried out with two strips along two ICESat target tracks. The work focuses on the comparison between the GOCE gravity field solutions with existing local an regional gravity field models over the area of Barcelona harbour. The study will estimate how GOCE works on SONMICAT-BCN calibration site in order to prepare future geomatics issues .

Future Coastal Population Growth and Exposure to Sea-Level Rise and Coastal Flooding - A Global Assessment

PubMed Central

Neumann, Barbara; Vafeidis, Athanasios T.; Zimmermann, Juliane; Nicholls, Robert J.

2015-01-01

Coastal zones are exposed to a range of coastal hazards including sea-level rise with its related effects. At the same time, they are more densely populated than the hinterland and exhibit higher rates of population growth and urbanisation. As this trend is expected to continue into the future, we investigate how coastal populations will be affected by such impacts at global and regional scales by the years 2030 and 2060. Starting from baseline population estimates for the year 2000, we assess future population change in the low-elevation coastal zone and trends in exposure to 100-year coastal floods based on four different sea-level and socio-economic scenarios. Our method accounts for differential growth of coastal areas against the land-locked hinterland and for trends of urbanisation and expansive urban growth, as currently observed, but does not explicitly consider possible displacement or out-migration due to factors such as sea-level rise. We combine spatially explicit estimates of the baseline population with demographic data in order to derive scenario-driven projections of coastal population development. Our scenarios show that the number of people living in the low-elevation coastal zone, as well as the number of people exposed to flooding from 1-in-100 year storm surge events, is highest in Asia. China, India, Bangladesh, Indonesia and Viet Nam are estimated to have the highest total coastal population exposure in the baseline year and this ranking is expected to remain largely unchanged in the future. However, Africa is expected to experience the highest rates of population growth and urbanisation in the coastal zone, particularly in Egypt and sub-Saharan countries in Western and Eastern Africa. The results highlight countries and regions with a high degree of exposure to coastal flooding and help identifying regions where policies and adaptive planning for building resilient coastal communities are not only desirable but essential. Furthermore, we identify needs for further research and scope for improvement in this kind of scenario-based exposure analysis. PMID:25760037

Future coastal population growth and exposure to sea-level rise and coastal flooding--a global assessment.

PubMed

Neumann, Barbara; Vafeidis, Athanasios T; Zimmermann, Juliane; Nicholls, Robert J

2015-01-01

Coastal zones are exposed to a range of coastal hazards including sea-level rise with its related effects. At the same time, they are more densely populated than the hinterland and exhibit higher rates of population growth and urbanisation. As this trend is expected to continue into the future, we investigate how coastal populations will be affected by such impacts at global and regional scales by the years 2030 and 2060. Starting from baseline population estimates for the year 2000, we assess future population change in the low-elevation coastal zone and trends in exposure to 100-year coastal floods based on four different sea-level and socio-economic scenarios. Our method accounts for differential growth of coastal areas against the land-locked hinterland and for trends of urbanisation and expansive urban growth, as currently observed, but does not explicitly consider possible displacement or out-migration due to factors such as sea-level rise. We combine spatially explicit estimates of the baseline population with demographic data in order to derive scenario-driven projections of coastal population development. Our scenarios show that the number of people living in the low-elevation coastal zone, as well as the number of people exposed to flooding from 1-in-100 year storm surge events, is highest in Asia. China, India, Bangladesh, Indonesia and Viet Nam are estimated to have the highest total coastal population exposure in the baseline year and this ranking is expected to remain largely unchanged in the future. However, Africa is expected to experience the highest rates of population growth and urbanisation in the coastal zone, particularly in Egypt and sub-Saharan countries in Western and Eastern Africa. The results highlight countries and regions with a high degree of exposure to coastal flooding and help identifying regions where policies and adaptive planning for building resilient coastal communities are not only desirable but essential. Furthermore, we identify needs for further research and scope for improvement in this kind of scenario-based exposure analysis.

Impact of Arctic shelf summer stratification on Holocene climate variability

NASA Astrophysics Data System (ADS)

Thibodeau, Benoit; Bauch, Henning A.; Knies, Jochen

2018-07-01

Understanding the dynamic of freshwater and sea-ice export from the Arctic is crucial to better comprehend the potential near-future climate change consequences. Here, we report nitrogen isotope data of a core from the Laptev Sea to shed light on the impact of the Holocene Siberian transgression on the summer stratification of the Laptev Sea. Our data suggest that the oceanographic setting was less favourable to sea-ice formation in the Laptev Sea during the early to mid-Holocene. It is only after the sea level reached a standstill at around 4 ka that the water column structure in the Laptev Sea became more stable. Modern-day conditions, often described as "sea-ice factory", were reached about 2 ka ago, after the development of a strong summer stratification. These results are consistent with sea-ice reconstruction along the Transpolar Drift, highlighting the potential contribution of the Laptev Sea to the export of freshwater from the Arctic Ocean.

Predicting future thermal habitat suitability of competing native and invasive fish species: from metabolic scope to oceanographic modelling.

PubMed

Marras, Stefano; Cucco, Andrea; Antognarelli, Fabio; Azzurro, Ernesto; Milazzo, Marco; Bariche, Michel; Butenschön, Momme; Kay, Susan; Di Bitetto, Massimiliano; Quattrocchi, Giovanni; Sinerchia, Matteo; Domenici, Paolo

2015-01-01

Global increase in sea temperatures has been suggested to facilitate the incoming and spread of tropical invaders. The increasing success of these species may be related to their higher physiological performance compared with indigenous ones. Here, we determined the effect of temperature on the aerobic metabolic scope (MS) of two herbivorous fish species that occupy a similar ecological niche in the Mediterranean Sea: the native salema (Sarpa salpa) and the invasive marbled spinefoot (Siganus rivulatus). Our results demonstrate a large difference in the optimal temperature for aerobic scope between the salema (21.8°C) and the marbled spinefoot (29.1°C), highlighting the importance of temperature in determining the energy availability and, potentially, the distribution patterns of the two species. A modelling approach based on a present-day projection and a future scenario for oceanographic conditions was used to make predictions about the thermal habitat suitability (THS, an index based on the relationship between MS and temperature) of the two species, both at the basin level (the whole Mediterranean Sea) and at the regional level (the Sicilian Channel, a key area for the inflow of invasive species from the Eastern to the Western Mediterranean Sea). For the present-day projection, our basin-scale model shows higher THS of the marbled spinefoot than the salema in the Eastern compared with the Western Mediterranean Sea. However, by 2050, the THS of the marbled spinefoot is predicted to increase throughout the whole Mediterranean Sea, causing its westward expansion. Nevertheless, the regional-scale model suggests that the future thermal conditions of Western Sicily will remain relatively unsuitable for the invasive species and could act as a barrier for its spread westward. We suggest that metabolic scope can be used as a tool to evaluate the potential invasiveness of alien species and the resilience to global warming of native species.

Natural and Human-Induced Variability in Barrier-Island Response to Sea Level Rise

NASA Astrophysics Data System (ADS)

Miselis, Jennifer L.; Lorenzo-Trueba, Jorge

2017-12-01

Storm-driven sediment fluxes onto and behind barrier islands help coastal barrier systems keep pace with sea level rise (SLR). Understanding what controls cross-shore sediment flux magnitudes is critical for making accurate forecasts of barrier response to increased SLR rates. Here, using an existing morphodynamic model for barrier island evolution, observations are used to constrain model parameters and explore potential variability in future barrier behavior. Using modeled drowning outcomes as a proxy for vulnerability to SLR, 0%, 28%, and 100% of the barrier is vulnerable to SLR rates of 4, 7, and 10 mm/yr, respectively. When only overwash fluxes are increased in the model, drowning vulnerability increases for the same rates of SLR, suggesting that future increases in storminess may increase island vulnerability particularly where sediment resources are limited. Developed sites are more vulnerable to SLR, indicating that anthropogenic changes to overwash fluxes and estuary depths could profoundly affect future barrier response to SLR.

Ecological niche modeling of coastal dune plants and future potential distribution in response to climate change and sea level rise.

PubMed

Mendoza-González, Gabriela; Martínez, M Luisa; Rojas-Soto, Octavio R; Vázquez, Gabriela; Gallego-Fernández, Juan B

2013-08-01

Climate change (CC) and sea level rise (SLR) are phenomena that could have severe impacts on the distribution of coastal dune vegetation. To explore this we modeled the climatic niches of six coastal dunes plant species that grow along the shoreline of the Gulf of Mexico and the Yucatan Peninsula, and projected climatic niches to future potential distributions based on two CC scenarios and SLR projections. Our analyses suggest that distribution of coastal plants will be severely limited, and more so in the case of local endemics (Chamaecrista chamaecristoides, Palafoxia lindenii, Cakile edentula). The possibilities of inland migration to the potential 'new shoreline' will be limited by human infrastructure and ecosystem alteration that will lead to a 'coastal squeeze' of the coastal habitats. Finally, we identified areas as future potential refuges for the six species in central Gulf of Mexico, and northern Yucatán Peninsula especially under CC and SLR scenarios. © 2013 John Wiley & Sons Ltd.

Natural and human-induced variability in barrier-island response to sea level rise

USGS Publications Warehouse

Miselis, Jennifer L.; Lorenzo-Trueba, Jorge

2017-01-01

Storm-driven sediment fluxes onto and behind barrier islands help coastal barrier systems keep pace with sea level rise (SLR). Understanding what controls cross-shore sediment flux magnitudes is critical for making accurate forecasts of barrier response to increased SLR rates. Here, using an existing morphodynamic model for barrier island evolution, observations are used to constrain model parameters and explore potential variability in future barrier behavior. Using modeled drowning outcomes as a proxy for vulnerability to SLR, 0%, 28%, and 100% of the barrier is vulnerable to SLR rates of 4, 7, and 10 mm/yr, respectively. When only overwash fluxes are increased in the model, drowning vulnerability increases for the same rates of SLR, suggesting that future increases in storminess may increase island vulnerability particularly where sediment resources are limited. Developed sites are more vulnerable to SLR, indicating that anthropogenic changes to overwash fluxes and estuary depths could profoundly affect future barrier response to SLR.

New Constraints from the Seychelles on the Timing and Magnitude of Peak Global Mean Sea Level during the Last Interglacial

NASA Astrophysics Data System (ADS)

Vyverberg, K.; Dechnik, B.; Dutton, A.; Webster, J.; Zwartz, D.; Edwards, R. L.

2016-12-01

Projecting the rate of future sea-level rise remains a primary challenge associated with continued climate change. However, uncertainties remain in our understanding of the rate of polar ice sheet retreat in warmer-than-present climates. To address this issue, we present a new sea level reconstruction from the tectonically stable granitic Seychelles based on Last Interglacial coral ages and elevations within their sedimentary and stratigraphic context, including estimates of paleo-water depth based on newly defined coralgal assemblages. The reef facies analyzed here has a narrow and shallow paleowater depth range (<2 m) providing increased control on the absolute position of sea level during this time period. Corrected for local glacial isostatic adjustment effects including the fingerprint associated with polar ice sheet mass loss, corals found in primary growth position within in situ coralgal reef framework confirm that global mean sea level (GMSL) was nearly 6 m above present early in the interglacial period. Each coral was dated in triplicate and screened for anomalous U-series geochemistry parameters. The combination of age-elevation data with the sedimentary micro and macro facies and stratigraphic analysis reveals a sea-level rise over 5-6 thousand years that is punctuated by repeated episodes of reef disturbance. These episodes are marked stratigraphically by coral rubble layers or extensive lateral encrustations of Millepora sp. that are infested with coral-dwelling barnacles. These disturbance layers may have been generated through internal reef processes and/or external agents, including coral disease, bleaching, predation, hurricanes, or sub-aerial exposure. In total, these new observations provide improved constraints on the timing, magnitude, and rates of sea-level rise during the Last Interglacial.

Predicting tidal marsh survival or submergence to sea-level rise using Holocene data

NASA Astrophysics Data System (ADS)

Horton, B.; Shennan, I.; Bradley, S.; Cahill, N.; Kirwan, M. L.; Kopp, R. E.; Shaw, T.

2017-12-01

Rising sea level threatens to permanently submerge tidal marsh environments if they cannot accrete faster than the rate of relative sea-level rise (RSLR). But regional and global model simulations of the future ability of marshes to maintain their elevation with respect to the tidal frame are uncertain. The compilation of empirical data for tidal marsh vulnerability is, therefore, essential to address disparities across these simulations. A hitherto unexplored source of empirical data are Holocene records of tidal marsh evolution. In particular, the marshes of Great Britain have survived and submerged while RSLR varied between -7.7 and 15.2 mm/yr, primarily because of the interplay between global ice-volume changes and regional isostatic processes. Here, we reveal the limits to marsh vulnerability are revealed through the analysis of over 400 reconstructions of tidal marsh submergence and conversion to tidal mud flat or open water from 54 regions in Great Britain during the Holocene. Holocene records indicate a 90% probability of tidal marsh submergence at sites with RSLR exceeding 7.3 mm/yr (95% CI: 6.6-8.6 mm/yr). Although most modern tidal marshes in Great Britain have not yet reached these sea-level rise limits, our empirical data suggest widespread concern over their ability to survive rates of sea-level rise in the 21st century under high emission scenarios. Integrating over the uncertainties in both sea-level rise predictions and the response of tidal marshes to sea-level rise, all of Great Britain has a >80% probability of marsh submergence under RCP 8.5 by 2100, with areas of south and eastern England, where the rate of RSLR is increased by glacio-isostatic subsidence, achieving this probability by 2040.

Preparing for Sea-level Rise: Conflicts and Opportunities in Coastal Wetlands Coexisting with Infrastructure

NASA Astrophysics Data System (ADS)

Rodriguez, J. F.; Saco, P. M.; Sandi, S. G.; Saintilan, N.; Riccardi, G.

2017-12-01

Even though on a large scale the sustainability and resilience of coastal wetlands to sea-level rise depends on the slope of the landscape and a balance between the rates of soil accretion and the sea-level rise, local man-made flow disturbances can have comparable effects. Coastal infrastructure controlling flow in the wetlands can pose an additional constraint on the adaptive capacity of these ecosystems, but can also present opportunities for targeted flow management to increase their resilience. Coastal wetlands in SE Australia are heavily managed and typically present infrastructure including flow control devices. How these flow control structures are operated respond to different ecological conservation objectives (i.e. bird, frog or fish habitat) that can sometimes be mutually exclusive. For example, promoting mangrove establishment to enhance fish habitat results in saltmarsh decline thus affecting bird habitat. Moreover, sea-level rise will change hydraulic conditions in wetlands and may result in some flow control structures and strategies becoming obsolete or even counterproductive. In order to address these problems and in support of future management of flows in coastal wetlands, we have developed a predictive tool for long-term wetland evolution that incorporates the effects of infrastructure and other perturbations to the tidal flow within the wetland (i.e. vegetation resistance) and determines how these flow conditions affect vegetation establishment and survival. We use the model to support management and analyse different scenarios of sea-level rise and flow control measures aimed at preserving bird habitat. Our results show that sea-level rise affects the efficiency of management measures and in some cases may completely override their effect. It also shows the potential of targeted flow management to compensate for the effects of sea-level rise.

Uncertainties in Future Regional Sea Level Trends: How to Deal with the Internal Climate Variability?

NASA Astrophysics Data System (ADS)

Becker, M.; Karpytchev, M.; Hu, A.; Deser, C.; Lennartz-Sassinek, S.

2017-12-01

Today, the Climate models (CM) are the main tools for forecasting sea level rise (SLR) at global and regional scales. The CM forecasts are accompanied by inherent uncertainties. Understanding and reducing these uncertainties is becoming a matter of increasing urgency in order to provide robust estimates of SLR impact on coastal societies, which need sustainable choices of climate adaptation strategy. These CM uncertainties are linked to structural model formulation, initial conditions, emission scenario and internal variability. The internal variability is due to complex non-linear interactions within the Earth Climate System and can induce diverse quasi-periodic oscillatory modes and long-term persistences. To quantify the effects of internal variability, most studies used multi-model ensembles or sea level projections from a single model ran with perturbed initial conditions. However, large ensembles are not generally available, or too small, and computationally expensive. In this study, we use a power-law scaling of sea level fluctuations, as observed in many other geophysical signals and natural systems, which can be used to characterize the internal climate variability. From this specific statistical framework, we (1) use the pre-industrial control run of the National Center for Atmospheric Research Community Climate System Model (NCAR-CCSM) to test the robustness of the power-law scaling hypothesis; (2) employ the power-law statistics as a tool for assessing the spread of regional sea level projections due to the internal climate variability for the 21st century NCAR-CCSM; (3) compare the uncertainties in predicted sea level changes obtained from a NCAR-CCSM multi-member ensemble simulations with estimates derived for power-law processes, and (4) explore the sensitivity of spatial patterns of the internal variability and its effects on regional sea level projections.

Impacts and Questions Regarding Future Sea Ice Conditions in the Canadian Arctic: Perspectives of the Canadian Ice Service

NASA Astrophysics Data System (ADS)

Wilson, K. J.; de Abreu, R.; Falkingham, J.

2006-12-01

The Canadian Ice Service (CIS) is responsible for monitoring and reporting sea ice conditions to support marine shipping and other maritime activities in Canada's Arctic. The location, concentration and movement of perennial (old) ice is the primary control on the level and type of shipping allowable and feasible in Canadian waters. As such, the likelihood and timing of a transition from a perennial ice regime to a seasonal one is of high interest to CIS marine clients. This presentation will review the kinds of questions we are being asked about future sea ice conditions, how we are responding to them given our current understanding, and what we base these responses on. This presentation will highlight the importance of climate change science, as well as present the type of science still needed.

Climate Change and Sea Level Rise: A Challenge to Science and Society

NASA Astrophysics Data System (ADS)

Plag, H.

2009-12-01

Society is challenged by the risk of an anticipated rise of coastal Local Sea Level (LSL) as a consequence of future global warming. Many low-lying and often subsiding and densely populated coastal areas are under risk of increased inundation, with potentially devastating consequences for the global economy, society, and environment. Faced with a trade-off between imposing the very high costs of coastal protection and adaptation upon today's national economies and leaving the costs of potential major disasters to future generations, governments and decision makers are in need of scientific support for the development of mitigation and adaptation strategies for the coastal zone. Low-frequency to secular changes in LSL are the result of many interacting Earth system processes. The complexity of the Earth system makes it difficult to predict Global Sea Level (GSL) rise and, even more so, LSL changes over the next 100 to 200 years. Humans have re-engineered the planet and changed major features of the Earth surface and the atmosphere, thus ruling out extrapolation of past and current changes into the future as a reasonable approach. The risk of rapid changes in ocean circulation and ice sheet mass balance introduces the possibility of unexpected changes. Therefore, science is challenged with understanding and constraining the full range of plausible future LSL trajectories and with providing useful support for informed decisions. In the face of largely unpredictable future sea level changes, monitoring of the relevant processes and development of a forecasting service on realistic time scales is crucial as decision support. Forecasting and "early warning" for LSL rise would have to aim at decadal time scales, giving coastal managers sufficient time to react if the onset of rapid changes would require an immediate response. The social, environmental, and economic risks associated with potentially large and rapid LSL changes are enormous. Therefore, in the light of the current uncertainties and the unpredictable nature of some of the forcing processes for LSL changes, the focus of scientific decision support may have to shift from projections of LSL trajectories on century time scales to the development of models and monitoring systems for a forecasting service on decadal time scales. The requirements for such a LSL forecasting service and the current obstacles will be discussed.

The Future of the Mississippi Delta: Shifting Baselines, Diminishing Resilience, and Growing Non-Sustainability

NASA Astrophysics Data System (ADS)

Detrick, R. S.; Hafner, K.; Davis, J. P.; Wilson, D.; Woodward, R.

2016-12-01

Ecosystems and human communities of the Mississippi delta developed with predictable basin inputs, stable sea level, and as an open system with a high degree of interaction among drainage basin inputs, deltaic plain, and the coastal sea. Human activity changed altered the coast and lowered predictability. Management has become very energy intensive and dependent on cheap resources with more hard engineering and less ecological engineering. Pervasive alteration of the basin and delta and global change have altered the baseline and change is accelerating. Climate change projections include not only sea-level rise, but also more stronger hurricanes, increased large river floods, and more intense rainfall events and droughts. A sustainable Mississippi is outside of the boundaries of the current CMP.

The Future of the Mississippi Delta: Shifting Baselines, Diminishing Resilience, and Growing Non-Sustainability

NASA Astrophysics Data System (ADS)

Day, J.

2017-12-01

Ecosystems and human communities of the Mississippi delta developed with predictable basin inputs, stable sea level, and as an open system with a high degree of interaction among drainage basin inputs, deltaic plain, and the coastal sea. Human activity changed altered the coast and lowered predictability. Management has become very energy intensive and dependent on cheap resources with more hard engineering and less ecological engineering. Pervasive alteration of the basin and delta and global change have altered the baseline and change is accelerating. Climate change projections include not only sea-level rise, but also more stronger hurricanes, increased large river floods, and more intense rainfall events and droughts. A sustainable Mississippi is outside of the boundaries of the current CMP.

Forecasting consequences of changing sea ice availability for Pacific walruses

USGS Publications Warehouse

Udevitz, Mark S.; Jay, Chadwick V.; Taylor, Rebecca; Fischbach, Anthony S.; Beatty, William S.; Noren, Shawn R.

2017-01-01

The accelerating rate of anthropogenic alteration and disturbance of environments has increased the need for forecasting effects of environmental change on fish and wildlife populations. Models linking projections of environmental change with behavioral responses and bioenergetic effects can provide a basis for these forecasts. There is particular interest in forecasting effects of projected reductions in sea ice availability on Pacific walruses (Odobenus rosmarus divergens). Declining extent of summer sea ice in the Chukchi Sea has caused Pacific walruses to increase use of coastal haulouts and decrease use of more productive offshore feeding areas. Such climate-induced changes in distribution and behavior could ultimately affect the status of the population. We developed behavioral models to relate changes in sea ice availability to adult female walrus movements and activity levels, and adapted previously developed bioenergetics models to relate those activity levels to energy requirements and the ability to meet those requirements. We then linked these models to general circulation model projections of future ice availability to forecast autumn body condition for female walruses during mid- and late-century time periods. Our results suggest that as sea ice becomes less available in the Chukchi Sea, female walruses will spend more time in the southwestern region of that sea, less time resting, and less time foraging. Median forecasted autumn body masses were 7–12% lower in future scenarios than during recent times, but posterior distributions broadly overlapped and median forecasted seasonal mass losses (15–34%) were comparable to seasonal mass losses routinely experienced by other pinnipeds. These seasonal reductions in body condition would be unlikely to result in demographic effects, but if walruses were unable to rebuild endogenous reserves while wintering in the Bering Sea, cumulative effects could have implications for reproduction and survival, ultimately affecting the status of the Pacific walrus population. Our approach provides a general framework for forecasting consequences of the broad range of environmental changes and anthropogenic disturbances that may affect bioenergetics through behavioral responses or changes in prey availability.

The impact of future sea-level rise on the global tides

NASA Astrophysics Data System (ADS)

Pickering, M. D.; Horsburgh, K. J.; Blundell, J. R.; Hirschi, J. J.-M.; Nicholls, R. J.; Verlaan, M.; Wells, N. C.

2017-06-01

Tides are a key component in coastal extreme water levels. Possible changes in the tides caused by mean sea-level rise (SLR) are therefore of importance in the analysis of coastal flooding, as well as many other applications. We investigate the effect of future SLR on the tides globally using a fully global forward tidal model: OTISmpi. Statistical comparisons of the modelled and observed tidal solutions demonstrate the skill of the refined model setup with no reliance on data assimilation. We simulate the response of the four primary tidal constituents to various SLR scenarios. Particular attention is paid to future changes at the largest 136 coastal cities, where changes in water level would have the greatest impact. Spatially uniform SLR scenarios ranging from 0.5 to 10 m with fixed coastlines show that the tidal amplitudes in shelf seas globally respond strongly to SLR with spatially coherent areas of increase and decrease. Changes in the M2 and S2 constituents occur globally in most shelf seas, whereas changes in K1 and O1 are confined to Asian shelves. With higher SLR tidal changes are often not proportional to the SLR imposed and larger portions of mean high water (MHW) changes are above proportional. Changes in MHW exceed ±10% of the SLR at 10% of coastal cities. SLR scenarios allowing for coastal recession tend increasingly to result in a reduction in tidal range. The fact that the fixed and recession shoreline scenarios result mainly in changes of opposing sign is explained by the effect of the perturbations on the natural period of oscillation of the basin. Our results suggest that coastal management strategies could influence the sign of the tidal amplitude change. The effect of a spatially varying SLR, in this case fingerprints of the initial elastic response to ice mass loss, modestly alters the tidal response with the largest differences at high latitudes.

Future Climate Change in the Baltic Sea Area

NASA Astrophysics Data System (ADS)

Bøssing Christensen, Ole; Kjellström, Erik; Zorita, Eduardo; Sonnenborg, Torben; Meier, Markus; Grinsted, Aslak

2015-04-01

Regional climate models have been used extensively since the first assessment of climate change in the Baltic Sea region published in 2008, not the least for studies of Europe (and including the Baltic Sea catchment area). Therefore, conclusions regarding climate model results have a better foundation than was the case for the first BACC report of 2008. This presentation will report model results regarding future climate. What is the state of understanding about future human-driven climate change? We will cover regional models, statistical downscaling, hydrological modelling, ocean modelling and sea-level change as it is projected for the Baltic Sea region. Collections of regional model simulations from the ENSEMBLES project for example, financed through the European 5th Framework Programme and the World Climate Research Programme Coordinated Regional Climate Downscaling Experiment, have made it possible to obtain an increasingly robust estimation of model uncertainty. While the first Baltic Sea assessment mainly used four simulations from the European 5th Framework Programme PRUDENCE project, an ensemble of 13 transient regional simulations with twice the horizontal resolution reaching the end of the 21st century has been available from the ENSEMBLES project; therefore it has been possible to obtain more quantitative assessments of model uncertainty. The literature about future climate change in the Baltic Sea region is largely built upon the ENSEMBLES project. Also within statistical downscaling, a considerable number of papers have been published, encompassing now the application of non-linear statistical models, projected changes in extremes and correction of climate model biases. The uncertainty of hydrological change has received increasing attention since the previous Baltic Sea assessment. Several studies on the propagation of uncertainties originating in GCMs, RCMs, and emission scenarios are presented. The number of studies on uncertainties related to downscaling and impact models is relatively small, but more are emerging. A large number of coupled climate-environmental scenario simulations for the Baltic Sea have been performed within the BONUS+ projects (ECOSUPPORT, INFLOW, AMBER and Baltic-C (2009-2011)), using various combinations of output from GCMs, RCMs, hydrological models and scenarios for load and emission of nutrients as forcing for Baltic Sea models. Such a large ensemble of scenario simulations for the Baltic Sea has never before been produced and enables for the first time an estimation of uncertainties.

Impacts of Sea Level Rise and Morphological Changes on Tidal Hydrodynamics in the Northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Passeri, D. L.; Hagen, S. C.; Plant, N. G.; Bilskie, M. V.

2014-12-01

Sea level rise (SLR) threatens coastal environments with increased erosion, inundation of wetlands, and changes in hydrodynamic patterns. Planning for the effects of SLR requires understanding the coupled response of SLR, geomorphic and hydrodynamic processes; this will provide crucial information for managers to make informed decisions for human and natural communities. Evaluating changes in tidal hydrodynamics under future scenarios is a key aspect for understanding the effects of SLR on coastal systems; tidal hydrodynamics influence inundation, circulation patterns, sediment transport processes, shoreline erosion, and productivity of marshes and other species. This study evaluates the dynamic effects of SLR and morphologic change on tidal hydrodynamics along the Northern Gulf of Mexico (NGOM) coast from Mississippi to the Florida panhandle. A large-scale hydrodynamic model is used to simulate astronomic tides under present (circa 2005), and future conditions (circa 2050 and 2100). The model is modified with specific SLR scenarios, morphology, and shorelines that represent the conditions at each of the time periods. Future sea levels for the years 2050 and 2100 are determined using the Parris et al. (2012) projections. To make projections of future morphology, a Bayesian Network (BN) is implemented. The BN is used to define relationships between forcing mechanisms and coastal responses based on long-term relative SLR, mean wave height, long-term shoreline change rates, mean tidal range, geomorphic setting and coastal slope. Probabilistic predictions of future shoreline positions and dune heights are developed for each SLR scenario for the years 2050 and 2100. The Digital Elevation Model (DEM) is then updated to reflect the future morphologic changes. Comparison of present and future conditions illustrates the hydrodynamic response of the system to the changing landscape. Changes in variables such as harmonic tidal constituents, tidal range, tidal prism, tidal datums, circulation patterns and inundation areas are examined. This provides a better understanding of the physical processes of the current state of the NGOM and gives insight into how future SLR and coastal landscape changes may affect hydrodynamics within the NGOM estuary systems.

Sea-level rise and shoreline retreat: time to abandon the Bruun Rule

NASA Astrophysics Data System (ADS)

Cooper, J. Andrew G.; Pilkey, Orrin H.

2004-11-01

In the face of a global rise in sea level, understanding the response of the shoreline to changes in sea level is a critical scientific goal to inform policy makers and managers. A body of scientific information exists that illustrates both the complexity of the linkages between sea-level rise and shoreline response, and the comparative lack of understanding of these linkages. In spite of the lack of understanding, many appraisals have been undertaken that employ a concept known as the "Bruun Rule". This is a simple two-dimensional model of shoreline response to rising sea level. The model has seen near global application since its original formulation in 1954. The concept provided an advance in understanding of the coastal system at the time of its first publication. It has, however, been superseded by numerous subsequent findings and is now invalid. Several assumptions behind the Bruun Rule are known to be false and nowhere has the Bruun Rule been adequately proven; on the contrary several studies disprove it in the field. No universally applicable model of shoreline retreat under sea-level rise has yet been developed. Despite this, the Bruun Rule is in widespread contemporary use at a global scale both as a management tool and as a scientific concept. The persistence of this concept beyond its original assumption base is attributed to the following factors: Appeal of a simple, easy to use analytical model that is in widespread use. Difficulty of determining the relative validity of 'proofs' and 'disproofs'. Ease of application. Positive advocacy by some scientists. Application by other scientists without critical appraisal. The simple numerical expression of the model. Lack of easy alternatives. The Bruun Rule has no power for predicting shoreline behaviour under rising sea level and should be abandoned. It is a concept whose time has passed. The belief by policy makers that it offers a prediction of future shoreline position may well have stifled much-needed research into the coastal response to sea-level rise.

The Future of GLOSS Sea Level Data Archaeology

NASA Astrophysics Data System (ADS)

Jevrejeva, S.; Bradshaw, E.; Tamisiea, M. E.; Aarup, T.

2014-12-01

Long term climate records are rare, consisting of unique and unrepeatable measurements. However, data do exist in analogue form in archives, libraries and other repositories around the world. The Global Sea Level Observing System (GLOSS) Group of Experts aims to provide advice on locating hidden tide gauge data, scanning and digitising records and quality controlling the resulting data. Long sea level data time series are used in Intergovernmental Panel on Climate Change (IPCC) assessment reports and climate studies, in oceanography to study changes in ocean currents, tides and storm surges, in geodesy to establish national datum and in geography and geology to monitor coastal land movement. GLOSS has carried out a number of data archaeology activities over the past decade, which have mainly involved sending member organisations questionnaires on their repositories. The Group of Experts is now looking at future developments in sea level data archaeology and how new technologies coming on line could be used by member organisations to make data digitisation and transcription more efficient. Analogue tide data comes in two forms charts, which record the continuous measurements made by an instrument, usually via a pen trace on paper ledgers containing written values of observations The GLOSS data archaeology web pages will provide a list of software that member organisations have reported to be suitable for the automatic digitisation of tide gauge charts. Transcribing of ledgers has so far proved more labour intensive and is usually conducted by people entering numbers by hand. GLOSS is exploring using Citizen Science techniques, such as those employed by the Old Weather project, to improve the efficiency of transcribing ledgers. The Group of Experts is also looking at recent advances in Handwritten Text Recognition (HTR) technology, which mainly relies on patterns in the written word, but could be adapted to work with the patterns inherent in sea level data.

Synoptic conditions of fine-particle transport to the last interglacial Red Sea -Dead Sea from Nd-Sr compositions of sediment cores

NASA Astrophysics Data System (ADS)

Stein, M.; Palchan, D.; Goldstein, S. L.; Almogi-Labin, A.; Tirosh, O.; Erel, Y.

2017-12-01

The last interglacial peak, Marine Isotope Stage 5e (MIS 5e), was associated with stronger northern hemisphere insolation, higher global sea levels and higher average global temperatures compared to the Holocene, and is considered as an analogue for a future warming world. In this perspective the present-day areas of the Sahara - Arabia deserts (the "desert belt") are of special interest since their margins are densely inhabited and global climate models predict enhanced aridity in these regions due to future warming. The Red Sea situated at the midst of the desert belt and the Dead Sea at the northern fringe of the desert belt comprise sensitive monitors for past hydroclimate changes in the Red Sea-Levant regions as global climate shifted from glacial to interglacial conditions. Here, we reconstruct the synoptic conditions that controlled desert dust transport to the Red Sea and the Dead Sea during MIS5e. The reconstruction is based on Nd-Sr isotopes and chemical composition of carbonate-free detritus recovered from sediment cores drilled at the deep floors of these water-bodies combined with data of contemporaneous dust storms transporting dust to the lake and sea floors. During Termination 2 ( 134-130 ka) the Sahara, Nile River desiccated and the Dead Sea watershed were under extreme dry conditions manifested by lake level drop, deposition of salt and enhanced transport of Sahara dusts to the entire studied transect. At the peak of the interglacial MIS 5e ( 130-120 ka), enhanced flooding activity mobilized local fine detritus from the surroundings of the Red Sea and the Dead Sea watershed into the water-bodies. This interval coincided with the Sapropel event S5 in the Mediterranean that responded to enhanced monsoon rains at the heads of the Blue Nile River. At the end of MIS 5e ( 120-116 ka) the effect of the regional floods faded and the Dead Sea and Red Sea areas re-entered sever arid conditions with salt deposition at the Dead Sea. Overall, the desert margins were under turbulent climate regime during the last interglacial period, fluctuating between contraction and expansions manifested with extreme enhanced flooding and extreme arid spells.

Centuries of thermal sea-level rise due to anthropogenic emissions of short-lived greenhouse gases

PubMed Central

Zickfeld, Kirsten

2017-01-01

Mitigation of anthropogenic greenhouse gases with short lifetimes (order of a year to decades) can contribute to limiting warming, but less attention has been paid to their impacts on longer-term sea-level rise. We show that short-lived greenhouse gases contribute to sea-level rise through thermal expansion (TSLR) over much longer time scales than their atmospheric lifetimes. For example, at least half of the TSLR due to increases in methane is expected to remain present for more than 200 y, even if anthropogenic emissions cease altogether, despite the 10-y atmospheric lifetime of this gas. Chlorofluorocarbons and hydrochlorofluorocarbons have already been phased out under the Montreal Protocol due to concerns about ozone depletion and provide an illustration of how emission reductions avoid multiple centuries of future TSLR. We examine the “world avoided” by the Montreal Protocol by showing that if these gases had instead been eliminated in 2050, additional TSLR of up to about 14 cm would be expected in the 21st century, with continuing contributions lasting more than 500 y. Emissions of the hydrofluorocarbon substitutes in the next half-century would also contribute to centuries of future TSLR. Consideration of the time scales of reversibility of TSLR due to short-lived substances provides insights into physical processes: sea-level rise is often assumed to follow air temperature, but this assumption holds only for TSLR when temperatures are increasing. We present a more complete formulation that is accurate even when atmospheric temperatures are stable or decreasing due to reductions in short-lived gases or net radiative forcing. PMID:28069937

Centuries of thermal sea-level rise due to anthropogenic emissions of short-lived greenhouse gases.

PubMed

Zickfeld, Kirsten; Solomon, Susan; Gilford, Daniel M

2017-01-24

Mitigation of anthropogenic greenhouse gases with short lifetimes (order of a year to decades) can contribute to limiting warming, but less attention has been paid to their impacts on longer-term sea-level rise. We show that short-lived greenhouse gases contribute to sea-level rise through thermal expansion (TSLR) over much longer time scales than their atmospheric lifetimes. For example, at least half of the TSLR due to increases in methane is expected to remain present for more than 200 y, even if anthropogenic emissions cease altogether, despite the 10-y atmospheric lifetime of this gas. Chlorofluorocarbons and hydrochlorofluorocarbons have already been phased out under the Montreal Protocol due to concerns about ozone depletion and provide an illustration of how emission reductions avoid multiple centuries of future TSLR. We examine the "world avoided" by the Montreal Protocol by showing that if these gases had instead been eliminated in 2050, additional TSLR of up to about 14 cm would be expected in the 21st century, with continuing contributions lasting more than 500 y. Emissions of the hydrofluorocarbon substitutes in the next half-century would also contribute to centuries of future TSLR. Consideration of the time scales of reversibility of TSLR due to short-lived substances provides insights into physical processes: sea-level rise is often assumed to follow air temperature, but this assumption holds only for TSLR when temperatures are increasing. We present a more complete formulation that is accurate even when atmospheric temperatures are stable or decreasing due to reductions in short-lived gases or net radiative forcing.

Future Flood Inundation and Damages from Storm Surge in the Coast of Virginia and Maryland with Projected Climate Change and Sea Level Rise Scenarios

NASA Astrophysics Data System (ADS)

Rezaie, A. M.; Ferreira, C.; Walls, M. A.

2016-12-01

The recurrent flood risks on coastal areas in the United States (US) due to hurricane wind and storm surge are likely to rise with warmer climate, frequent storms, and increasing coastal population. Recent studies suggested that the global financial losses from hurricanes will be doubled by 2100 due to combined impact of climate change, sea level rise (SLR) and intensified hurricanes. While the predicted average SLR for the Mid-Atlantic region of the US is 2.2 meter, some coastal areas in Virginia (VA) and Maryland (MD) are expected to experience a 0.7 to 1.6m and 0.6 to 1.7m SLR respectively. Nearly 80 percent of the total $5.3 billion property damage by Hurricane Isabel in 2003 was within VA and MD. In order to provide a quantitative assessment of the future flooding and associated damages for projected climate change and SLR scenarios, this study integrated state-of-the-art coastal numerical model ADCIRC with a careful economic valuation exercise of flood damages. The study area covers the entire coastal zone of VA and MD focusing on regions that are in the vicinity of the Chesapeake Bay and the Atlantic Ocean with high susceptibility to storm surge and flooding. Multiple climate change land cover scenarios generated by the United States Geological Survey (USGS) under a series of the IPCC's Emissions Scenarios are incorporated in the modeling approach to integrate climate change whereas local SLR projections are included to provide the regional aspects of future risks. Preliminary results for hurricane Isabel (2003) shows that a 2.3m rise in sea level can cause storm surges rising up to 3-4m in the coastal areas. While a 0.5m SLR makes the range 1-2.5m in the affected areas. It is also seen that higher increase in the sea level not only causes higher range of inundation but a greater extent of flood as well. The projected inland flooding extents are highest for the SRES A2 Scenario. Alongside an estimate of future loss and damage will be prepared to assist in future planning for the coastal areas near the Chesapeake Bay regions and finally progressing in developing a climate resilient coast. Furthermore the estimated damages will be applied to quantify the functionality and benefits of natural and nature-based features for coastal defense for future changes in climate and development.

Improving the Predictability of Severe Water Levels along the Coasts of Marginal Seas

NASA Astrophysics Data System (ADS)

Ridder, N. N.; de Vries, H.; van den Brink, H.; De Vries, H.

2016-12-01

Extreme water levels can lead to catastrophic consequences with severe societal and economic repercussions. Particularly vulnerable are countries that are largely situated below sea level. To support and optimize forecast models, as well as future adaptation efforts, this study assesses the modeled contribution of storm surges and astronomical tides to total water levels under different air-sea momentum transfer parameterizations in a numerical surge model (WAQUA/DCSMv5) of the North Sea. It particularly focuses on the implications for the representation of extreme and rapidly recurring severe water levels over the past decades based on the example of the Netherlands. For this, WAQUA/DCSMv5, which is currently used to forecast coastal water levels in the Netherlands, is forced with ERA Interim reanalysis data. Model results are obtained from two different methodologies to parameterize air-sea momentum transfer. The first calculates the governing wind stress forcing using a drag coefficient derived from the conventional approach of wind speed dependent Charnock constants. The other uses instantaneous wind stress from the parameterization of the quasi-linear theory applied within the ECMWF wave model which is expected to deliver a more realistic forcing. The performance of both methods is tested by validating the model output with observations, paying particular attention to their ability to reproduce rapidly succeeding high water levels and extreme events. In a second step, the common features of and connections between these events are analyzed. The results of this study will allow recommendations for the improvement of water level forecasts within marginal seas and support decisions by policy makers. Furthermore, they will strengthen the general understanding of severe and extreme water levels as a whole and help to extend the currently limited knowledge about clustering events.

Assessing and Mitigating Hurricane Storm Surge Risk in a Changing Environment

NASA Astrophysics Data System (ADS)

Lin, N.; Shullman, E.; Xian, S.; Feng, K.

2017-12-01

Hurricanes have induced devastating storm surge flooding worldwide. The impacts of these storms may worsen in the coming decades because of rapid coastal development coupled with sea-level rise and possibly increasing storm activity due to climate change. Major advances in coastal flood risk management are urgently needed. We present an integrated dynamic risk analysis for flooding task (iDraft) framework to assess and manage coastal flood risk at the city or regional scale, considering integrated dynamic effects of storm climatology change, sea-level rise, and coastal development. We apply the framework to New York City. First, we combine climate-model projected storm surge climatology and sea-level rise with engineering- and social/economic-model projected coastal exposure and vulnerability to estimate the flood damage risk for the city over the 21st century. We derive temporally-varying risk measures such as the annual expected damage as well as temporally-integrated measures such as the present value of future losses. We also examine the individual and joint contributions to the changing risk of the three dynamic factors (i.e., sea-level rise, storm change, and coastal development). Then, we perform probabilistic cost-benefit analysis for various coastal flood risk mitigation strategies for the city. Specifically, we evaluate previously proposed mitigation measures, including elevating houses on the floodplain and constructing flood barriers at the coast, by comparing their estimated cost and probability distribution of the benefit (i.e., present value of avoided future losses). We also propose new design strategies, including optimal design (e.g., optimal house elevation) and adaptive design (e.g., flood protection levels that are designed to be modified over time in a dynamic and uncertain environment).

Impact of Atmospheric Aerosols on Solar Photovoltaic Electricity Generation in China

NASA Astrophysics Data System (ADS)

Li, X.; Mauzerall, D. L.; Wagner, F.; Peng, W.; Yang, J.

2016-12-01

Hurricanes have induced devastating storm surge flooding worldwide. The impacts of these storms may worsen in the coming decades because of rapid coastal development coupled with sea-level rise and possibly increasing storm activity due to climate change. Major advances in coastal flood risk management are urgently needed. We present an integrated dynamic risk analysis for flooding task (iDraft) framework to assess and manage coastal flood risk at the city or regional scale, considering integrated dynamic effects of storm climatology change, sea-level rise, and coastal development. We apply the framework to New York City. First, we combine climate-model projected storm surge climatology and sea-level rise with engineering- and social/economic-model projected coastal exposure and vulnerability to estimate the flood damage risk for the city over the 21st century. We derive temporally-varying risk measures such as the annual expected damage as well as temporally-integrated measures such as the present value of future losses. We also examine the individual and joint contributions to the changing risk of the three dynamic factors (i.e., sea-level rise, storm change, and coastal development). Then, we perform probabilistic cost-benefit analysis for various coastal flood risk mitigation strategies for the city. Specifically, we evaluate previously proposed mitigation measures, including elevating houses on the floodplain and constructing flood barriers at the coast, by comparing their estimated cost and probability distribution of the benefit (i.e., present value of avoided future losses). We also propose new design strategies, including optimal design (e.g., optimal house elevation) and adaptive design (e.g., flood protection levels that are designed to be modified over time in a dynamic and uncertain environment).

The competing impacts of climate change and nutrient reductions on dissolved oxygen in Chesapeake Bay

NASA Astrophysics Data System (ADS)

Irby, Isaac D.; Friedrichs, Marjorie A. M.; Da, Fei; Hinson, Kyle E.

2018-05-01

The Chesapeake Bay region is projected to experience changes in temperature, sea level, and precipitation as a result of climate change. This research uses an estuarine-watershed hydrodynamic-biogeochemical modeling system along with projected mid-21st-century changes in temperature, freshwater flow, and sea level rise to explore the impact climate change may have on future Chesapeake Bay dissolved-oxygen (DO) concentrations and the potential success of nutrient reductions in attaining mandated estuarine water quality improvements. Results indicate that warming bay waters will decrease oxygen solubility year-round, while also increasing oxygen utilization via respiration and remineralization, primarily impacting bottom oxygen in the spring. Rising sea level will increase estuarine circulation, reducing residence time in bottom waters and increasing stratification. As a result, oxygen concentrations in bottom waters are projected to increase, while oxygen concentrations at mid-depths (3 < DO < 5 mg L-1) will typically decrease. Changes in precipitation are projected to deliver higher winter and spring freshwater flow and nutrient loads, fueling increased primary production. Together, these multiple climate impacts will lower DO throughout the Chesapeake Bay and negatively impact progress towards meeting water quality standards associated with the Chesapeake Bay Total Maximum Daily Load. However, this research also shows that the potential impacts of climate change will be significantly smaller than improvements in DO expected in response to the required nutrient reductions, especially at the anoxic and hypoxic levels. Overall, increased temperature exhibits the strongest control on the change in future DO concentrations, primarily due to decreased solubility, while sea level rise is expected to exert a small positive impact and increased winter river flow is anticipated to exert a small negative impact.

Modeling future scenarios of light attenuation and potential seagrass success in a eutrophic estuary

USGS Publications Warehouse

del Barrio, Pilar; Ganju, Neil K.; Aretxabaleta, Alfredo L.; Hayn, Melanie; García, Andrés; Howarth, Robert W.

2014-01-01

Estuarine eutrophication has led to numerous ecological changes, including loss of seagrass beds. One potential cause of these losses is a reduction in light availability due to increased attenuation by phytoplankton. Future sea level rise will also tend to reduce light penetration and modify seagrass habitat. In the present study, we integrate a spectral irradiance model into a biogeochemical model coupled to the Regional Ocean Model System (ROMS). It is linked to a bio-optical seagrass model to assess potential seagrass habitat in a eutrophic estuary under future nitrate loading and sea-level rise scenarios. The model was applied to West Falmouth Harbor, a shallow estuary located on Cape Cod (Massachusetts) where nitrate from groundwater has led to eutrophication and seagrass loss in landward portions of the estuary. Measurements of chlorophyll, turbidity, light attenuation, and seagrass coverage were used to assess the model accuracy. Mean chlorophyll based on uncalibrated in-situ fluorometry varied from 28 μg L−1 at the landward-most site to 6.5 μg L−1 at the seaward site, while light attenuation ranged from 0.86 to 0.45 m-1. The model reproduced the spatial variability in chlorophyll and light attenuation with RMS errors of 3.72 μg L−1 and 0.07 m-1 respectively. Scenarios of future nitrate reduction and sea-level rise suggest an improvement in light climate in the landward basin with a 75% reduction in nitrate loading. This coupled model may be useful to assess habitat availability changes due to eutrophication and sediment resuspension and fully considers spatial variability on the tidal timescale.

Scenario-based projections of future urban inundation within a coupled hydrodynamic model framework: A case study in Dongguan City, China

NASA Astrophysics Data System (ADS)

Wu, Xushu; Wang, Zhaoli; Guo, Shenglian; Liao, Weilin; Zeng, Zhaoyang; Chen, Xiaohong

2017-04-01

One major threat to cities at present is the increased inundation hazards owing to changes in climate and accelerated human activity. Future evolution of urban inundation is still an unsolved issue, given large uncertainties in future environmental conditions within urbanized areas. Developing model techniques and urban inundation projections are essential for inundation management. In this paper, we proposed a 2D hydrodynamic inundation model by coupling SWMM and LISFLOOD-FP models, and revealed how future urban inundation would evolve for different storms, sea level rise and subsidence scenarios based on the developed model. The Shiqiao Creek District (SCD) in Dongguan City was used as the case study. The model ability was validated against the June 13th, 2008 inundation event, which occurred in SCD, and proved capable of simulating dynamic urban inundation. Scenario analyses revealed a high degree of consistency in the inundation patterns among different storms, with larger magnitudes corresponding to greater return periods. Inundations across SCD generally vary as a function of storm intensity, but for lowlands or regions without drainage facilities inundations tend to aggravate over time. In riverfronts, inundations would exacerbate with sea level rise or subsidence; however, the inland inundations are seemingly insensitive to both factors. For the combined scenario of 100-yr storm, 0.5 m subsidence and 0.7 m sea level rise, the riverside inundations would occur much in advance, whilst catastrophic inundations sweep across SCD. Furthermore, the optimal low-impact development found for this case study includes 0.2 km2 of permeable pavements, 0.1 km2 of rain barrels and 0.7 km2 of green roofs.

The Orinoco megadelta as a conservation target in the face of the ongoing and future sea level rise.

PubMed

Vegas-Vilarrúbia, T; Hernández, E; Rull, Valentí; Rull Vegas, Elisa

2015-05-15

Currently, risk assessments related to rising sea levels and the adoption of defensive or adaptive measures to counter these sea level increases are underway for densely populated deltas where economic losses might be important, especially in the developed world. However, many underpopulated deltas harbouring high biological and cultural diversity are also at risk but will most likely continue to be ignored as conservation targets. In this study, we explore the potential effects of erosion, inundation and salinisation on one of the world's comparatively underpopulated megadeltas, the Orinoco Delta. With a 1 m sea level rise expected to occur by 2100, several models predict a moderate erosion of the delta's shorelines, migration or loss of mangroves, general inundation of the delta with an accompanying submersion of wetlands, and an increase in the distance to which sea water intrudes into streams, resulting in harm to the freshwater biota and resources. The Warao people are the indigenous inhabitants of the Orinoco Delta and currently are subject to various socioeconomic stressors. Changes due to sea level rise will occur extremely rapidly and cause abrupt shifts in the Warao's traditional environments and resources, resulting in migrations and abandonment of their ancestral territories. However, evidence indicates that deltaic aggradation/accretion processes at the Orinoco delta due to allochthonous sediment input and vegetation growth could be elevating the surface of the land, keeping pace with the local sea level rise. Other underpopulated and large deltas of the world also may risk immeasurable biodiversity and cultural losses and should not be forgotten as important conservation targets. Copyright © 2015. Published by Elsevier B.V.

The Linear Predictability of Sea Level: A Benchmark

NASA Astrophysics Data System (ADS)

Sonnewald, M.; Wunsch, C.; Heimbach, P.

2016-12-01

A benchmark of linear predictive skill of global sea level is presented, complimenting more complicated model studies of future predictive skill. Sea level is of great socioeconomic interest, as most of the worlds population live by the sea. Currently, the spread in model projections suggests poor predictive skill outside the seasonal cycle. We use 20 years of data from the ECCOv4 state estimate (1992-2012), assessing the variance attributable to the seasons and the linear predictability potential of the deseasoned component of sea level. The Northern Hemisphere has large regions where the seasons make up >90% of the variance, particularly in the western boundary current regions and zonal bands along the equator. The deaseasoned sea level is more dominant in the Southern Hemisphere, particularly in the Southern Ocean. We treat the deseasoned sea level as a weakly stationary random process, whose predictability is given by the covariance structure. Fitting an ARMA(n,m) model, we choose the order using the Akaike and Bayesian Information Criteria (AIC and BIC). The AIC is more appropriate, with generally higher orders chosen and offering slightly more predictive accuracy. Monthly detrended data shows skill generally of the order of a few months, with isolated regions of twelve months or more. With the trend, the predictive skill increases, particularly in the South Pacific. We assess the annually averaged data, although our time-series is too short to assess the variability. There is some predictive skill, which is enhanced if the trend is not removed. A major caveat of our approach is that we test and train our model on the same dataset due to the short duration of available data.

Assessing the Potential for Inland Migration of a Northeastern Salt Marsh

NASA Astrophysics Data System (ADS)

Farron, S.; FitzGerald, D.; Hughes, Z. J.

2017-12-01

It is often assumed that as sea level rises, salt marshes will expand inland. If the slope of the upland is relatively flat and sufficient sediment is available, marshes should be able to spread horizontally and grow vertically in order to maintain their areal extent. However, in cases where marshes are backed by steeper slopes, or sediment supply is limited, rising sea level will produce minimal gains along the landward edge insufficient to offset potential losses along the seaward edge. This study uses future sea level rise scenarios to project areal losses for the Great Marsh in Massachusetts, the largest continuous salt marsh in New England. Land area covered by salt marsh is defined by surface elevation. Annual sediment input to the system is estimated based on the areal extent of high and low marsh, historical accretion rates for each, and known organic/inorganic ratios. Unlike other studies, sediment availability is considered to be finite, and future accretion rates are limited based on the assumption that the system is presently receiving the maximum sediment input available. The Great Marsh is dominated by high marsh; as sea level rises, it will convert to low marsh, vastly altering the ecological and sedimentological dynamics of the system. If it is assumed that former high marsh areas will build vertically at the increased rate associated with low marsh, then much of the total marsh area will be maintained. However, this may be an unrealistic assumption due to the low levels of suspended sediment within the Great Marsh system. Modeling the evolution of the Great Marsh by assuming that the current accretion rate is the maximum possible for this system reveals much greater losses than models assuming an unlimited sediment supply would predict (17% less marsh by 2115). In addition, uplands surrounding the Great Marsh have been shaped by glaciation, leaving numerous drumlins and other glacial landforms. Compared to the flat backbarrier, the surrounding hills offer little opportunity for expansion. Modeling results suggest that sea level rise over the next century will convert 12 km2 of marsh to open water, but only 9 km2 of new marsh will be formed through uplands inundation and sedimentation. These findings suggest that sea level rise presents a particular threat to the Great Marsh, and marshes like it.

Future Earth Coasts: The Mississippi and Yangtze Rivers as Examples

NASA Astrophysics Data System (ADS)

D'Elia, C.; Xu, K.; Chen, Z.; Day, J.; Le Tissier, M.

2016-02-01

Deltas and estuaries are productive and fertile links between the land and the sea. Deltas occupy only about 5% of the Earth's surface but sustain over a half billion people all around the world. Many river deltas are endangered because of extensive dam and levee construction, declining sediment supply, groundwater withdrawal, relative sea level rise and severe coastal erosion, leading to a variety of threats to natural, economic and social systems. About 630 million people now live at an elevation of 10 m or less above mean sea level, and maintaining sustainable land with a rising sea will be a challenging problem for many major deltaic coasts and cities in the next century. Stemming from 20 years of LOICZ (Land-Ocean Interactions in the Coastal Zone), Future Earth Coasts is a new global initiative that seeks to enable the scientific and social scientific communities to build knowledge through collaborative processes to better understand and address the profound and urgent changes occurring in vulnerable coastal zones. The topics of this comparative study are the Mississippi and Yangtze (Changjiang) Rivers, the largest in the United States and China, respectively. We use these two rivers as examples to evaluate current conditions and catalyze future discussion. The Mississippi and Yangtze both have had long-term observations of physical and biological processes that affect human activities, making it possible to quantify both natural and anthropogenic impacts. We also consider the limits to concept of sustainability for the Earth's biosphere and human civilization, and emphasize biophysical constraints and demographic challenges.

A model ensemble for projecting multi‐decadal coastal cliff retreat during the 21st century

USGS Publications Warehouse

Limber, Patrick; Barnard, Patrick; Vitousek, Sean; Erikson, Li

2018-01-01

Sea cliff retreat rates are expected to accelerate with rising sea levels during the 21st century. Here we develop an approach for a multi‐model ensemble that efficiently projects time‐averaged sea cliff retreat over multi‐decadal time scales and large (>50 km) spatial scales. The ensemble consists of five simple 1‐D models adapted from the literature that relate sea cliff retreat to wave impacts, sea level rise (SLR), historical cliff behavior, and cross‐shore profile geometry. Ensemble predictions are based on Monte Carlo simulations of each individual model, which account for the uncertainty of model parameters. The consensus of the individual models also weights uncertainty, such that uncertainty is greater when predictions from different models do not agree. A calibrated, but unvalidated, ensemble was applied to the 475 km‐long coastline of Southern California (USA), with 4 SLR scenarios of 0.5, 0.93, 1.5, and 2 m by 2100. Results suggest that future retreat rates could increase relative to mean historical rates by more than two‐fold for the higher SLR scenarios, causing an average total land loss of 19 – 41 m by 2100. However, model uncertainty ranges from +/‐ 5 – 15 m, reflecting the inherent difficulties of projecting cliff retreat over multiple decades. To enhance ensemble performance, future work could include weighting each model by its skill in matching observations in different morphological settings

Multiproxy assessment of Holocene relative sea-level changes in the western Mediterranean: sea-level variability and improvements in the definition of the isostatic signal

NASA Astrophysics Data System (ADS)

Vacchi, Matteo; Rovere, Alessio; Marriner, Nick; Morhange, Christophe; Spada, Giorgio; Fontana, Alessandro

2016-04-01

After the review of 918 radiocarbon dated Relative Sea-Level (RSL) data-points we present here the first quality-controlled database constraining the Holocene sea-level histories of the western Mediterranean Sea (Spain, France, Italy, Slovenia, Croatia, Malta and Tunisia). We reviewed and standardized the geological RSL data-points using a new multi-proxy methodology based on: (1) modern taxa assemblages in Mediterranean lagoons and marshes; (2) beachrock characteristics (cement fabric and chemistry, sedimentary structures); and (3) the modern distribution of Mediterranean fixed biological indicators. These RSL data-points were coupled with the large number of archaeological RSL indicators available for the western Mediterranean. We assessed the spatial variability of RSL histories for 22 regions and compared these with the ICE-5G VM2 GIA model. In the western Mediterranean, RSL rose continuously for the whole Holocene with a sudden slowdown at ~7.5 ka BP and a further deceleration during the last ~4.0 ka BP, after which time observed RSL changes are mainly related to variability in isostatic adjustment. The sole exception is southern Tunisia, where data show evidence of a mid-Holocene high-stand compatible with the isostatic impacts of the melting history of the remote Antarctic ice sheet. Our results indicate that late-Holocene sea-level rise was significantly slower than the current one. First estimates of GIA contribution indicate that, at least in the northwestern sector, it accounts at least for the 25-30% of the ongoing sea-level rise recorded by Mediterranean tidal gauges. Such contribution is less constrained at lower latitudes due to the lower quality of the late Holocene index points. Future applications of spatio-temporal statistical techniques are required to better quantify the gradient of the isostatic contribution and to provide improved context for the assessment of 20th century acceleration of Mediterranean sea-level rise.

Spaceborne Synthetic Aperture Radar Survey of Subsidence in Hampton Roads, Virginia (USA).

PubMed

Bekaert, D P S; Hamlington, B D; Buzzanga, B; Jones, C E

2017-11-07

Over the past century, the Hampton Roads area of the Chesapeake Bay region has experienced one of the highest rates of relative sea level rise on the Atlantic coast of the United States. This rate of relative sea level rise results from a combination of land subsidence, which has long been known to be present in the region, and rising seas associated with global warming on long timescales and exacerbated by shifts in ocean dynamics on shorter timescales. An understanding of the current-day magnitude of each component is needed to create accurate projections of future relative sea level rise upon which to base planning efforts. The objective of this study is to estimate the land component of relative sea level rise using interferometric synthetic aperture radar (InSAR) analysis applied to ALOS-1 synthetic aperture radar data acquired during 2007-2011 to generate high-spatial resolution (20-30 m) estimates of vertical land motion. Although these results are limited by the uncertainty associated with the small set of available historical SAR data, they highlight both localized rates of high subsidence and a significant spatial variability in subsidence, emphasizing the need for further measurement, which could be done with Sentinel-1 and NASA's upcoming NISAR mission.

Sea, Lake, and Overland Surge from Hurricanes (SLOSH) Inundation for Categories 2 and 4

EPA Pesticide Factsheets

The file geodatabase (fgdb) contains the Sea, Lake, and Overland Surge from Hurricanes (SLOSH) Maximum of Maximums (MOM) model for hurricane categories 2 and 4. The EPA Office of Research & Development (ORD) modified the original model from NOAA to fit the model parameters for the Buzzards Bay region. The models show storm surge extent for the Mattapoisett area and therefore the flooding area was reduced to the study area. Areas of flooding that were not connected to the main water body were removed. The files in the geodatabase are:Cat2_SLR0_Int_Feet_dissolve_Mattapoisett: Current Category 2 hurricane with 0 ft sea level riseCat4_SLR0_Int_Feet_dissolve_Mattapoisett: Current Category 4 hurricane with 0 ft sea level riseCat4_SLR4_Int_Feet_dissolve_Mattapoisett: Future Category 4 hurricane with 4 feet sea level riseThe features support the Weather Ready Mattapoisett story map, which can be accessed via the following link:https://epa.maps.arcgis.com/apps/MapJournal/index.html?appid=1ff4f1d28a254cb689334799d94b74e2

XXI century projections of wind-wave conditions and sea-level rise in the Black sea

NASA Astrophysics Data System (ADS)

Polonsky, A.; Garmashov, A.; Fomin, V.; Valchev, N.; Trifonova, E.

2012-04-01

Projection of regional climate changes for XXI century is one of the priorities of EC environmental programme. Potential worsening of the waves' statistics, sea level rise and extreme surges are the principal negative consequences of the climate change for marine environment. That is why the main purpose of this presentation is to discuss the above issue for the Black sea region (with a strong focus to the south-west subregion because the maximum heights of waves exceeding 10 m occur just here) using output of several global coupled models (GCM) for XXI century, wave simulation, long-term observations of sea level and statistical techniques. First of all we tried to choose the best coupled model (s) simulated the Black sea climate change and variability using the control experiments for 20 century (203). The principal result is as follows. There is not one model which is simulating adequately even one atmospheric parameter for all seasons. Therefore we considered (for the climate projection) different outputs form various models. When it was possible we calculated also the ensemble mean projection for the selected model (s) and emission scenarios. To calculate the wave projection we used the output of SWAN model forced by the GCM wind projection for 2010 to 2100. To estimate the sea level rise in XXI century and future surges statistics we extrapolate the observed sea level rise tendencies, statistical relation between wave heights and sea level and wave scenarios. Results show that in general, the climate change in XXI century doesn't lead to the catastrophic change of the Black sea wind-wave statistics including the extreme waves in the S-W Black sea. The typical atmospheric pattern leading to the intense storm in the S-W Black sea is characterized by the persistent anticyclonic area to the North of the Black sea and cyclonic conditions in the Southern Black sea region. Such pressure pattern causes persistent and strong eastern or north-eastern wind which generates the high waves in the S-E Black sea. The climate projections show that the frequency of such atmospheric pattern will not principally increase. The recent probability of the extreme wave height (exceeding 8 to10 m) in the S-W Black sea (~1 occurrence per 10 years) will not be much worse in XXI century. Similar conclusion is true for the storm surges along the Bulgarian coastline. Expected sea level rise in the Black sea basin for XXI century due to regional climate changes is about 2 mm per year (±50%). However, some Black sea subregions (such as Odessa and Varna bay) are characterized by fivefold sea level rise because of the local land subsidence. So, this geomorphologic effect is the most dangerous local consequence for the sustainable development and management of the coastal zone in such subregions. This study was supported by EC project "THESEUS".

Implications of Sea Level Rise on Coastal Flood Hazards

NASA Astrophysics Data System (ADS)

Roeber, V.; Li, N.; Cheung, K.; Lane, P.; Evans, R. L.; Donnelly, J. P.; Ashton, A. D.

2012-12-01

Recent global and local projections suggest the sea level will be on the order of 1 m or higher than the current level by the end of the century. Coastal communities and ecosystems in low-lying areas are vulnerable to impacts resulting from hurricane or large swell events in combination with sea-level rise. This study presents the implementation and results of an integrated numerical modeling package to delineate coastal inundation due to storm landfalls at future sea levels. The modeling package utilizes a suite of numerical models to capture both large-scale phenomena in the open ocean and small-scale processes in coastal areas. It contains four components to simulate (1) meteorological conditions, (2) astronomical tides and surge, (3) wave generation, propagation, and nearshore transformation, and (4) surf-zone processes and inundation onto dry land associated with a storm event. Important aspects of this package are the two-way coupling of a spectral wave model and a storm surge model as well as a detailed representation of surf and swash zone dynamics by a higher-order Boussinesq-type wave model. The package was validated with field data from Hurricane Ivan of 2005 on the US Gulf coast and applied to tropical and extratropical storm scenarios respectively at Eglin, Florida and Camp Lejeune, North Carolina. The results show a nonlinear increase of storm surge level and nearshore wave energy with a rising sea level. The exacerbated flood hazard can have major consequences for coastal communities with respect to erosion and damage to infrastructure.

Potential increase in coastal wetland vulnerability to sea-level rise suggested by considering hydrodynamic attenuation effects

PubMed Central

Rodríguez, José F.; Saco, Patricia M.; Sandi, Steven; Saintilan, Neil; Riccardi, Gerardo

2017-01-01

The future of coastal wetlands and their ecological value depend on their capacity to adapt to the interacting effects of human impacts and sea-level rise. Even though extensive wetland loss due to submergence is a possible scenario, its magnitude is highly uncertain due to limited understanding of hydrodynamic and bio-geomorphic interactions over time. In particular, the effect of man-made drainage modifications on hydrodynamic attenuation and consequent wetland evolution is poorly understood. Predictions are further complicated by the presence of a number of vegetation types that change over time and also contribute to flow attenuation. Here, we show that flow attenuation affects wetland vegetation by modifying its wetting-drying regime and inundation depth, increasing its vulnerability to sea-level rise. Our simulations for an Australian subtropical wetland predict much faster wetland loss than commonly used models that do not consider flow attenuation. PMID:28703130

Potential increase in coastal wetland vulnerability to sea-level rise suggested by considering hydrodynamic attenuation effects

NASA Astrophysics Data System (ADS)

Rodríguez, José F.; Saco, Patricia M.; Sandi, Steven; Saintilan, Neil; Riccardi, Gerardo

2017-07-01

The future of coastal wetlands and their ecological value depend on their capacity to adapt to the interacting effects of human impacts and sea-level rise. Even though extensive wetland loss due to submergence is a possible scenario, its magnitude is highly uncertain due to limited understanding of hydrodynamic and bio-geomorphic interactions over time. In particular, the effect of man-made drainage modifications on hydrodynamic attenuation and consequent wetland evolution is poorly understood. Predictions are further complicated by the presence of a number of vegetation types that change over time and also contribute to flow attenuation. Here, we show that flow attenuation affects wetland vegetation by modifying its wetting-drying regime and inundation depth, increasing its vulnerability to sea-level rise. Our simulations for an Australian subtropical wetland predict much faster wetland loss than commonly used models that do not consider flow attenuation.

Projected future climate change and Baltic Sea ecosystem management.

PubMed

Andersson, Agneta; Meier, H E Markus; Ripszam, Matyas; Rowe, Owen; Wikner, Johan; Haglund, Peter; Eilola, Kari; Legrand, Catherine; Figueroa, Daniela; Paczkowska, Joanna; Lindehoff, Elin; Tysklind, Mats; Elmgren, Ragnar

2015-06-01

Climate change is likely to have large effects on the Baltic Sea ecosystem. Simulations indicate 2-4 °C warming and 50-80 % decrease in ice cover by 2100. Precipitation may increase ~30 % in the north, causing increased land runoff of allochthonous organic matter (AOM) and organic pollutants and decreased salinity. Coupled physical-biogeochemical models indicate that, in the south, bottom-water anoxia may spread, reducing cod recruitment and increasing sediment phosphorus release, thus promoting cyanobacterial blooms. In the north, heterotrophic bacteria will be favored by AOM, while phytoplankton production may be reduced. Extra trophic levels in the food web may increase energy losses and consequently reduce fish production. Future management of the Baltic Sea must consider the effects of climate change on the ecosystem dynamics and functions, as well as the effects of anthropogenic nutrient and pollutant load. Monitoring should have a holistic approach, encompassing both autotrophic (phytoplankton) and heterotrophic (e.g., bacterial) processes.

Modelling the thermosteric contribution to global and regional sea-level rise during the last interglacial

NASA Astrophysics Data System (ADS)

Singarayer, Joy; Stone, Emma; Whipple, Matthew; Lunt, Dan; Bouttes, Nathaelle; Gregory, Jonathan

2014-05-01

Global sea level during the last interglacial is likely to have been between 5.5 and 9m above present (Dutton and Lambeck, 2012). Recent calculations, taking into account latest NEEM ice core information, suggest that Greenland would probably not have contributed more than 2.2m to this (Stone et al, 2013), implying a considerable contribution from Antarctica. Previous studies have suggested a significant loss from the West Antarctic ice-sheet (e.g. Holden et al, 2010), which could be initiated following a collapse of the Atlantic Meridional Overturning Circulation (AMOC) and resultant warming in the Southern Ocean. Here, model simulations with FAMOUS and HadCM3 have been performed of the last interglacial under various scenarios of reduced Greenland and Antarctic ice-sheet configurations, and with and without collapsed AMOC. Thermal expansion and changes in regional density structure (resulting from ocean circulation changes) can also influence sea level, in addition to ice mass effects discussed thus far. The HadCM3 and FAMOUS simulations will be used to estimate the contribution to global and regional sea level change in interglacials from the latter two factors using a similar methodology to the IPCC TAR/AR4 estimations of future sea level rise (Gregory and Lowe, 2000). The HadCM3 and FAMOUS both have a rigid lid in their ocean model, and consequently a fixed ocean volume. Thermal expansion can, however, be calculated as a volume change from in-situ density (a prognostic variable from the model). Relative sea surface topography will then be estimated from surface pressure gradients and changes in atmospheric pressure. Dutton A., and Lambeck K., 2013. Ice Volume and Sea Level During the Last Interglacial. Science, 337, 216-219 Gregory J.M. and Lowe J.A., 2000. Predictions of global and regional sea-level using AOGCMs with and without flux adjustment. GRL, 27, 3069-3072 Holden P. et al., 2010. Interhemispheric coupling, the West Antarctic Ice Sheet and warm Antarctic interglacials. Clim. Past, 6, 431-443 Stone E.J., et al., 2013. Quantification of the Greenland ice sheet contribution to Last Interglacial sea level rise. Clim. Past, 9, 621-639

A scenario framework to explore the future migration and adaptation in deltas: A multi-scale and participatory approach

NASA Astrophysics Data System (ADS)

Kebede, Abiy S.; Nicholls, Robert J.; Allan, Andrew; Arto, Inaki; Cazcarro, Ignacio; Fernandes, Jose A.; Hill, Chris T.; Hutton, Craig W.; Kay, Susan; Lawn, Jon; Lazar, Attila N.; Whitehead, Paul W.

2017-04-01

Coastal deltas are home for over 500 million people globally, and they have been identified as one of the most vulnerable coastal environments during the 21st century. They are susceptible to multiple climatic (e.g., sea-level rise, storm surges, change in temperature and precipitation) and socio-economic (e.g., human-induced subsidence, population and urbanisation changes, GDP growth) drivers of change. These drivers also operate at multiple scales, ranging from local to global and short- to long-term. This highlights the complex challenges deltas face in terms of both their long-term sustainability as well as the well-being of their residents and the health of ecosystems that support the livelihood of large (often very poor) population under uncertain changing conditions. A holistic understanding of these challenges and the potential impacts of future climate and socio-economic changes is central for devising robust adaptation policies. Scenario analysis has long been identified as a strategic management tool to explore future climate change and its impacts for supporting robust decision-making under uncertainty. This work presents the overall scenario framework, methodology, and processes adopted for the development of scenarios in the DECCMA* project. DECCMA is analysing the future of three deltas in South Asia and West Africa: (i) the Ganges-Brahmaputra-Meghna (GBM) delta (Bangladesh/India), (ii) the Mahanadi delta (India), and (iii) the Volta delta (Ghana). This includes comparisons between these three deltas. Hence, the scenario framework comprises a multi-scale hybrid approach, with six levels of scenario considerations: (i) global (climate change, e.g., sea-level rise, temperature change; and socio-economic assumptions, e.g., population and urbanisation changes, GDP growth); (ii) regional catchments (e.g., river flow modelling), (iii) regional seas (e.g., fisheries modelling), (iv) regional politics (e.g., transboundary disputes), (v) national (e.g., socio-economic factors), and (vi) delta-scale (e.g., future adaptation and migration policies) scenarios. The framework includes and combines expert-based and participatory approaches and provides improved specification of the role of scenarios to analyse the future state of adaptation and migration across the three deltas. It facilitates the development of appropriate and consistent endogenous and exogenous scenario futures: (i) at the delta-scale, (ii) across all deltas, and (iii) with wider climate change, environmental change, and adaptation & migration research. Key words: Coastal deltas, sea-level rise, migration and adaptation, multi-scale scenarios, participatory approach *DECCMA (Deltas, Vulnerability & Climate Change: Migration & Adaptation) project is part of the Collaborative ADAPTATION Research Initiative in Africa and Asia (CARIAA), with financial support from the UK Government's Department for International Development (DFID) and the International Development Research Centre (IDRC), Canada.

Incorporating Infrastructure and Vegetation Effects on Sea Level Rise Predictions in Low-Gradient Coastal Landscapes

NASA Astrophysics Data System (ADS)

Rodriguez, J. F.; Sandi Rojas, S.; Trivisonno, F.; Saco, P. M.; Riccardi, G.

2015-12-01

At the regional and global scales, coastal management and planning for future sea level rise scenarios is typically supported by modelling tools that predict the expected inundation extent. These tools rely on a number of simplifying assumptions that, in some cases, may result in important overestimation or underestimation of the inundation extent. One of such cases is coastal wetlands, where vegetation strongly affects both the magnitude and the timing of inundation. Many coastal wetlands display other forms of flow restrictions due to, for example, infrastructure or drainage works, which also alters the inundation patterns. In this contribution we explore the effects of flow restrictions on inundation patterns under sea level rise conditions in coastal wetlands. We use a dynamic wetland evolution model that not only incorporates the effects of flow restrictions due to culverts, bridges and weirs as well as vegetation, but also considers that vegetation changes as a consequence of increasing inundation. We apply our model to a coastal wetland in Australia and compare predictions of our model to predictions using conventional approaches. We found that some restrictions accentuate detrimental effects of sea level rise while others moderate them. We also found that some management strategies based on flow redistribution that provide short term solution may result more damaging in the long term if sea level rise is considered.

Probabilistic framework for assessing the ice sheet contribution to sea level change.

PubMed

Little, Christopher M; Urban, Nathan M; Oppenheimer, Michael

2013-02-26

Previous sea level rise (SLR) assessments have excluded the potential for dynamic ice loss over much of Greenland and Antarctica, and recently proposed "upper bounds" on Antarctica's 21st-century SLR contribution are derived principally from regions where present-day mass loss is concentrated (basin 15, or B15, drained largely by Pine Island, Thwaites, and Smith glaciers). Here, we present a probabilistic framework for assessing the ice sheet contribution to sea level change that explicitly accounts for mass balance uncertainty over an entire ice sheet. Applying this framework to Antarctica, we find that ongoing mass imbalances in non-B15 basins give an SLR contribution by 2100 that: (i) is comparable to projected changes in B15 discharge and Antarctica's surface mass balance, and (ii) varies widely depending on the subset of basins and observational dataset used in projections. Increases in discharge uncertainty, or decreases in the exceedance probability used to define an upper bound, increase the fractional contribution of non-B15 basins; even weak spatial correlations in future discharge growth rates markedly enhance this sensitivity. Although these projections rely on poorly constrained statistical parameters, they may be updated with observations and/or models at many spatial scales, facilitating a more comprehensive account of uncertainty that, if implemented, will improve future assessments.

Using GRACE and climate model simulations to predict mass loss of Alaskan glaciers through 2100

DOE PAGES

Wahr, John; Burgess, Evan; Swenson, Sean

2016-05-30

Glaciers in Alaska are currently losing mass at a rate of ~–50 Gt a –1, one of the largest ice loss rates of any regional collection of mountain glaciers on Earth. Existing projections of Alaska's future sea-level contributions tend to be divergent and are not tied directly to regional observations. Here we develop a simple, regional observation-based projection of Alaska's future sea-level contribution. We compute a time series of recent Alaska glacier mass variability using monthly GRACE gravity fields from August 2002 through December 2014. We also construct a three-parameter model of Alaska glacier mass variability based on monthly ERA-Interimmore » snowfall and temperature fields. When these three model parameters are fitted to the GRACE time series, the model explains 94% of the variance of the GRACE data. Using these parameter values, we then apply the model to simulated fields of monthly temperature and snowfall from the Community Earth System Model, to obtain predictions of mass variations through 2100. Here, we conclude that mass loss rates may increase between –80 and –110 Gt a –1by 2100, with a total sea-level rise contribution of 19 ± 4 mm during the 21st century.« less

A geological perspective on potential future sea-level rise

PubMed Central

Rohling, Eelco J.; Haigh, Ivan D.; Foster, Gavin L.; Roberts, Andrew P.; Grant, Katharine M.

2013-01-01

During ice-age cycles, continental ice volume kept pace with slow, multi-millennial scale, changes in climate forcing. Today, rapid greenhouse gas (GHG) increases have outpaced ice-volume responses, likely committing us to > 9 m of long-term sea-level rise (SLR). We portray a context of naturally precedented SLR from geological evidence, for comparison with historical observations and future projections. This context supports SLR of up to 0.9 (1.8) m by 2100 and 2.7 (5.0) m by 2200, relative to 2000, at 68% (95%) probability. Historical SLR observations and glaciological assessments track the upper 68% limit. Hence, modern change is rapid by past interglacial standards but within the range of ‘normal’ processes. The upper 95% limit offers a useful low probability/high risk value. Exceedance would require conditions without natural interglacial precedents, such as catastrophic ice-sheet collapse, or activation of major East Antarctic mass loss at sustained CO2 levels above 1000 ppmv. PMID:24336564

Assessment of salinity intrusion in the James and Chickahominy Rivers as a result of simulated sea-level rise in Chesapeake Bay, East Coast, USA.

PubMed

Rice, Karen C; Hong, Bo; Shen, Jian

2012-11-30

Global sea level is rising, and the relative rate in the Chesapeake Bay region of the East Coast of the United States is greater than the worldwide rate. Sea-level rise can cause saline water to migrate upstream in estuaries and rivers, threatening freshwater habitat and drinking-water supplies. The effects of future sea-level rise on two tributaries of Chesapeake Bay, the James and Chickahominy (CHK) Rivers, were evaluated in order to quantify the salinity change with respect to the magnitude of sea-level rise. Such changes are critical to: 1) local floral and faunal habitats that have limited tolerance ranges to salinity; and 2) a drinking-water supply for the City of Newport News, Virginia. By using the three-dimensional Hydrodynamic-Eutrophication Model (HEM-3D), sea-level rise scenarios of 30, 50, and 100 cm, based on the U.S. Climate Change Science Program for the mid-Atlantic region for the 21st century, were evaluated. The model results indicate that salinity increases in the entire river as sea level rises and that the salinity increase in a dry year is greater than that in a typical year. In the James River, the salinity increase in the middle-to-upper river (from 25 to 50 km upstream of the mouth) is larger than that in the lower and upper parts of the river. The maximum mean salinity increase would be 2 and 4 ppt for a sea-level rise of 50 and 100 cm, respectively. The upstream movement of the 10 ppt isohaline is much larger than the 5 and 20 ppt isohalines. The volume of water with salinity between 10 and 20 ppt would increase greatly if sea level rises 100 cm. In the CHK River, with a sea-level rise of 100 cm, the mean salinity at the drinking-water intake 34 km upstream of the mouth would be about 3 ppt in a typical year and greater than 5 ppt in a dry year, both far in excess of the U.S. Environmental Protection Agency's secondary standard for total dissolved solids for drinking water. At the drinking-water intake, the number of days of salinity greater than 0.1 ppt increases with increasing sea-level rise; during a dry year, 0.1 ppt would be exceeded for more than 100 days with as small a rise as 30 cm. Copyright © 2012 Elsevier Ltd. All rights reserved.

Assessment of salinity intrusion in the James and Chickahominy Rivers as a result of simulated sea-level rise in Chesapeake Bay, East Coast, USA

USGS Publications Warehouse

Rice, Karen; Bo Hong,; Jian Shen,

2012-01-01

Global sea level is rising, and the relative rate in the Chesapeake Bay region of the East Coast of the United States is greater than the worldwide rate. Sea-level rise can cause saline water to migrate upstream in estuaries and rivers, threatening freshwater habitat and drinking-water supplies. The effects of future sea-level rise on two tributaries of Chesapeake Bay, the James and Chickahominy (CHK) Rivers, were evaluated in order to quantify the salinity change with respect to the magnitude of sea-level rise. Such changes are critical to: 1) local floral and faunal habitats that have limited tolerance ranges to salinity; and 2) a drinking-water supply for the City of Newport News, Virginia. By using the three-dimensional Hydrodynamic-Eutrophication Model (HEM-3D), sea-level rise scenarios of 30, 50, and 100 cm, based on the U.S. Climate Change Science Program for the mid-Atlantic region for the 21st century, were evaluated. The model results indicate that salinity increases in the entire river as sea level rises and that the salinity increase in a dry year is greater than that in a typical year. In the James River, the salinity increase in the middle-to-upper river (from 25 to 50 km upstream of the mouth) is larger than that in the lower and upper parts of the river. The maximum mean salinity increase would be 2 and 4 ppt for a sea-level rise of 50 and 100 cm, respectively. The upstream movement of the 10 ppt isohaline is much larger than the 5 and 20 ppt isohalines. The volume of water with salinity between 10 and 20 ppt would increase greatly if sea level rises 100 cm. In the CHK River, with a sea-level rise of 100 cm, the mean salinity at the drinking-water intake 34 km upstream of the mouth would be about 3 ppt in a typical year and greater than 5 ppt in a dry year, both far in excess of the U.S. Environmental Protection Agency's secondary standard for total dissolved solids for drinking water. At the drinking-water intake, the number of days of salinity greater than 0.1 ppt increases with increasing sea-level rise; during a dry year, 0.1 ppt would be exceeded for more than 100 days with as small a rise as 30 cm.

Increased Flooding Risk - Accelerating Threat and Stakeholder Response

NASA Astrophysics Data System (ADS)

Atkinson, L. P.; Ezer, T.; De Young, R.; McShane, M. K.; McFarlane, B.

2012-12-01

Coastal cities have been adapting to coastal flooding for centuries. Now, with increased population along the coast combined with increased flooding because of sea level rise (SLR) the vulnerability of coastal cities has increased significantly. In this paper we will discuss the physical threat of accelerating sea level rise and the response of stakeholders. Sallenger et al (2012) stated "... we present evidence of recently accelerated SLR in a unique 1,000-km-long hotspot on the highly populated North American Atlantic coast north of Cape Hatteras and show that it is consistent with a modeled fingerprint of dynamic SLR." In the Northeast Hotspot (NEH) dynamic processes such as Gulf Stream transport can cause local sea level differences (Ezer, 2001). Sweet et al (2009) attributed the anomalously high sea level along the mid-Atlantic in 2009 to dynamic SLR. A recent paper (Ezer and Corlett, 2012 submitted), focused on Chesapeake Bay, confirms Sallenger et al. These accelerations suggest that the higher estimates of SLR in IPCC reports may be better estimates. The combination of local sea level rise and acceleration, even with average coastal storm surge, results in increased vulnerability and economic losses. We will use three examples of stakeholder response to this threat: shipbuilding, cities and insurance. Nuclear aircraft carrier drydock in Newport News, VA - The only drydock where nuclear powered aircraft carriers are built flooded during Hurricane Isabel. A study showed that with a 1 meter sea level rise and no change in storm severity they would have 'Major Flooding' every 4 months rather than every 27 years. Cities infrastructure - In a recent report on sea level rise, the Hampton Roads Planning District Commission (representing nearly 2m people) found that "sea level rise will be a major issue", "there is not yet official state or federal guidance for addressing sea level rise", "…the "…U.S. Army Corps of Engineers has developed guidance…" for their projects, and "…subsidence …. is not well-documented". Studies sponsored by the City of Norfolk for example suggest massive tidal barriers. Flood insurance - Flood insurance is available only from the National Flood Insurance Program (NFIP), not from private insurers. NFIP has a current deficit of about 18B, which is estimated to increase by about 2B annually. The rates are subsidized and do not reflect the true risk of coastal flooding and do not incorporate the likelihood of future sea-level rise. In effect, the subsidy promotes increased building on the coast, leading to increased deficits in the tax-payer financed program. Risk-based flood insurance pricing would lead to less coastal development, therefore decreasing the tax base of the community. Stakeholder needs - Planning for increased flooding due to sea level rise extends 50 to 100 years given the lifetime of infrastructure. Planners need guidance and error estimates. To make adequate predictions for users we must understand the various components of sea level rise including subsidence, global sea level rise and regional and local dynamic sea level rise. Predictions of regional sea level rise will be presented in the context of existing infrastructure such as NASA research facilities and the city of Norfolk, Virginia.

Simulation of coastal floodings during a typhoon event with the consideration of future sea-level rises.

NASA Astrophysics Data System (ADS)

Shu-Huei, Jhang; Chih-Chung, Wen; Dong-Jiing, Doong; Cheng-Han, Tsai

2017-04-01

Taiwan is an Island in the western Pacific Ocean and experienced more than 3 typhoons in a year. Typhoons bring intense rainfall, high waves, and storm surges, which often resulted in coastal flooding. The flooding can be aggravated by the sea level rise due to the global warming, which may subject Taiwan's coastal areas to more serious damage in the future than present. The objectives of this study are to investigate the flooding caused by typhoons in the Annan District, Tainan, a city on the southwest coast of Taiwan by numerical simulations, considering the effects of sea-level rises according to the level suggested by the 5th Assessment Report of IPCC (Intergovernmental Panel on Climate Change) for 2050 and 2100, respectively. The simulations were carried out by using MIKE21 HD (a hydrodynamic model) and MIKE21 SW (a spectral wave model). In our simulation, we used an intense typhoon, named Soudelor, as our base typhoon, which made its landfall on the east coast of Taiwan in the summer of 2015, traveled through the width of the island, and exited the island to the north of Tainan. The reasons we pick this typhoon are that it passed near our objective area, wind field data for this typhoon are available, and we have well documented coastal wave and water level measurements during the passage of Typhoon Soudelor. We firstly used ECMWF (European Centre for Medium-Range Weather Forecasts) wind field data to reconstruct typhoon waves and storm surges for this typhoon by using coupled MIKE21 SW and MIKE21 HD in a regional model. The resultant simulated wave height and sea-level height matched satisfactorily with the measured data. The wave height and storm surge calculated by the regional model provided the boundary conditions for our fine-grid domain. Then different sea-level rises suggested by the IPCC were incorporated into the fine-grid model. Since river discharge due to intense rainfall has also to be considered for coastal flooding, our fine-grid models encompass the estuary of River Yanshui, and measured upstream river discharges were used to simulate the interactions among tide, current, and wave near the estuary of Yanshui River. Our preliminary results showed that with only the effect of rainwater discharge, the maximum surface level of the river during the storm near the estuary was 1.4 m, which is not higher than the river embankments. With the storm surge, the river level at the same location was 2.2 m. With the storm surge and sea-level rise, the maximum river levels near the estuary were 3.6 m and 3.9 m for 2050 and 2100 scenarios, respective. These levels were higher than the embankment height of 3 m. This showed that due to higher sea-level, the area near the estuary will be flooded.

Studying the impact of climate change on flooding in 12 river basins using CCSM4 output

NASA Astrophysics Data System (ADS)

Thiele-Eich, I.; Hopson, T. M.; Gilleland, E.; Lamarque, J.; Hu, A.

2011-12-01

The goal of this study is to analyze the impact of climate change on flood frequency changes in twelve large river basins by assessing the changes in upper catchment precipitation as well as the impact of sea-level rise at the river mouths. Using the recently released model output of the CCSM4 for upper catchment precipitation in twelve large river basins as well as the sea-level rise anomalies at the respective river mouths, we assess the impact of climate change on the return periods of flooding in the individual basins. Upper catchment precipitation, discharge as well as annual mean thermosteric sea-level rise are taken from the four CCSM4 1° 20th Century ensemble members as well as from six CCSM4 1° ensemble members for the RCP scenarios RCP8.5, 6.0, 4.5 and 2.6. In a next step, return levels are compared from both 20th century and future model simulations for time slices at 2030, 2050, 2070 and 2090. It can be seen that what is e.g. a 20 year flood in present-day climate has a return period of ~15/10 years (RCP 2.6/8.5) in 2070. This effect strengthens as time progresses in the 21st century. Especially in low-lying countries such as Bangladesh, changes in sea-level rise can be expected to influence present-day flood characteristics. Sea-level rise anomalies for the 21st century are taken from CCSM4 model output at each of the river mouths. The backwater effect of sea-level rise can be estimated by referring to the geometry of the river channel and calculating an effective additional discharge both at the river mouth and inland. Judging from our work, the increase in effective discharge due to sea-level rise cannot be neglected when discussing flooding in the respective river basins. Impact of sea-level rise on changes in return levels will be investigated further. To blend both precipitation and sea-level effects together, we use extreme-value theory to calculate how the tails of the current river discharge distribution in both the lower and middle reaches of the river basins will be impacted by changing climate.

Model Projections of Future Fluvial Sediment Delivery to Major Deltas Under Environmental Change

NASA Astrophysics Data System (ADS)

Darby, S. E.; Dunn, F.; Nicholls, R. J.; Cohen, S.; Zarfl, C.

2017-12-01

Deltas are important hot spots for climate change impacts on which over half a billion people live worldwide. Most of the world's deltas are sinking as a result of natural and anthropogenic subsidence and due to eustatic sea level rise. The ability to predict rates of delta aggradation is therefore critical to assessments of the extent to which sedimentation can potentially offset sea level rise, but our ability to make such predictions is severely hindered by a lack of insight into future trends of the fluvial sediment load supplied to their deltas by feeder watersheds. To address this gap we investigate fluvial sediment fluxes under future environmental change for a selection (47) of the world's major river deltas. Specifically, we employed the numerical model WBMsed to project future variations in mean annual fluvial sediment loads under a range of environmental change scenarios that account for changes in climate, socio-economics and dam construction. Our projections indicate a clear decrease (by 34 to 41% on average, depending on the specific scenario) in future fluvial sediment supply to most of the 47 deltas. These reductions in sediment delivery are driven primarily by anthropogenic disturbances, with reservoir construction being the most influential factor globally. Our results indicate the importance of developing new management strategies for reservoir construction and operation.

Bedrock Erosion Surfaces Record Former East Antarctic Ice Sheet Extent

NASA Astrophysics Data System (ADS)

Paxman, Guy J. G.; Jamieson, Stewart S. R.; Ferraccioli, Fausto; Bentley, Michael J.; Ross, Neil; Armadillo, Egidio; Gasson, Edward G. W.; Leitchenkov, German; DeConto, Robert M.

2018-05-01

East Antarctica hosts large subglacial basins into which the East Antarctic Ice Sheet (EAIS) likely retreated during past warmer climates. However, the extent of retreat remains poorly constrained, making quantifying past and predicted future contributions to global sea level rise from these marine basins challenging. Geomorphological analysis and flexural modeling within the Wilkes Subglacial Basin are used to reconstruct the ice margin during warm intervals of the Oligocene-Miocene. Flat-lying bedrock plateaus are indicative of an ice sheet margin positioned >400-500 km inland of the modern grounding zone for extended periods of the Oligocene-Miocene, equivalent to a 2-m rise in global sea level. Our findings imply that if major EAIS retreat occurs in the future, isostatic rebound will enable the plateau surfaces to act as seeding points for extensive ice rises, thus limiting extensive ice margin retreat of the scale seen during the early EAIS.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bougamont, M.; Christoffersen, P.; Price, S. F.

Ongoing, centennial-scale flow variability within the Ross ice streams of West Antarctica suggests that the present-day positive mass balance in this region may reverse in the future. Here we use a three-dimensional ice sheet model to simulate ice flow in this region over 250 years. The flow responds to changing basal properties, as a subglacial till layer interacts with water transported in an active subglacial hydrological system. We show that a persistent weak bed beneath the tributaries of the dormant Kamb Ice Stream is a source of internal ice flow instability, which reorganizes all ice streams in this region, leadingmore » to a reduced (positive) mass balance within decades and a net loss of ice within two centuries. This hitherto unaccounted for flow variability could raise sea level by 5 mm this century. Furthermore, better constraints on future sea level change from this region will require improved estimates of geothermal heat flux and subglacial water transport.« less

Sea Level Rise, Rainfall and Coastal Flooding in Northeastern U.S. Cities Vivien Gornitz, Radley Horton, Philip Orton, Nickitas Georgas, Alan Blumberg, and Cynthia Rosenzweig

NASA Astrophysics Data System (ADS)

Gornitz, V.; Horton, R. M.; Orton, P. M.; Georgas, N.; Blumberg, A. F.; Rosenzweig, C.

2012-12-01

Populations and infrastructure along much of the northeastern coast of the United States will become increasingly vulnerable to the impacts of rising sea level and storm surges over the coming century. This vulnerability is amplified by regional land subsidence and likely also by shifts in ocean circulation. Building upon recent studies for the New York City Panel on Climate Change (NPCC), New York State ClimAid assessment, and the latest U.S. National Climate Assessment, we report new regional sea level rise projections based on the latest CMIP-5 global climate models (GCMs) and RCP emission scenarios, adjusted for revised glacial ice melt contributions, and other factors such as gravitational effects, land water storage, and changes in the Atlantic Meriodional Overturning Circulation (AMOC). Over the coming two years, GCM-derived sea level outputs for future decades will be utilized in risk assessments for coastal flooding in New York City, Boston, and Philadelphia, as part of the Consortium for Climate Risk in the Urban Northeast-RISA project. The Stevens Institute Estuarine and Coastal Ocean Model (sECOM) will be used to produce best estimates (including uncertainty ranges) of sea level rise impacts for a wide range of tropical and extra-tropical cyclones for the 2010s, 2050s, and 2080s. Major improvements over prior studies include (a) the use of a detailed, extensively validated ocean model, and (b) inclusion of rainfall and river flow influences on coastal flooding, which affect flood levels in enclosed tidal waterways (e.g., the Hudson and Delaware Rivers), and which are also likely important in coastal confluence zones of impermeable urbanized watersheds. In addition to the sea level rise results, we present initial model validation results for historical storms.

Effects of Projected Future Climate Change on Groundwater Recharge and Storage for Two Coastal Aquifers in Guanacaste Province, Costa Rica

NASA Astrophysics Data System (ADS)

Kolb, C.

2017-12-01

Climate change is expected to pose a significant threat to water resources in the future. Guanacaste Province, located in northwestern Costa Rica, has a unique climate that is influenced by the Pacific Ocean and Caribbean Sea, as well as the Central Cordillera mountain range. Although the region experiences a marked rainy season between May and November, the hot, dry summers often stress water resources. Climate change projections suggest increased temperatures and reduced precipitation for the region, which will further stress water supplies. This study focuses on the effects of climate change on groundwater resources for two coastal aquifers, Potrero and Brasilito. The UZF model package coupled with the finite difference groundwater flow model MODFLOW were used to evaluate the effect of climate change on groundwater recharge and storage. A potential evapotranspiration model was used to estimate groundwater infiltration rates used in the MODFLOW model. Climate change projections for temperature, precipitation, and sea level rise were used to develop climate scenarios, which were compared to historical data. Preliminary results indicate that climate change could reduce future recharge, especially during the dry season. Additionally, the coastal aquifers are at increased risk of reduced storage and increased salinization due to the reductions in groundwater recharge and sea level rise. Climate change could also affect groundwater quality in the region, disrupting the ecosystem and impairing a primary source of drinking water.

Simulation of the ground-water flow system at Naval Submarine Base Bangor and vicinity, Kitsap County, Washington

USGS Publications Warehouse

Heeswijk, Marijke van; Smith, Daniel T.

2002-01-01

An evaluation of the interaction between ground-water flow on Naval Submarine Base Bangor and the regional-flow system shows that for selected alternatives of future ground-water pumping on and near the base, the risk is low that significant concentrations of on-base ground-water contamination will reach off-base public-supply wells and hypothetical wells southwest of the base. The risk is low even if worst-case conditions are considered ? no containment and remediation of on-base contamination. The evaluation also shows that future saltwater encroachment of aquifers below sea level may be possible, but this determination has considerable uncertainty associated with it. The potential effects on the ground-water flow system resulting from four hypothetical ground-water pumping alternatives were considered, including no change in 1995 pumping rates, doubling the rates, and 2020 rates estimated from population projections with two different pumping distributions. All but a continuation of 1995 pumping rates demonstrate the possibility of future saltwater encroachment in the Sea-level aquifer on Naval Submarine Base Bangor. The amount of time it would take for encroachment to occur is unknown. For all pumping alternatives, future saltwater encroachment in the Sea-level aquifer also may be possible along Puget Sound east and southeast of the base. Future saltwater encroachment in the Deep aquifer also may be possible throughout large parts of the study area. Projections of saltwater encroachment are least certain outside the boundaries of Naval Submarine Base Bangor. The potential effects of the ground-water pumping alternatives were evaluated by simulating the ground-water flow system with a three-dimensional uniform-density ground-water flow model. The model was calibrated by trial-and-error by minimizing differences between simulated and measured or estimated variables. These included water levels from prior to January 17, 1977 (termed 'predevelopment'), water-level drawdowns since predevelopment until April 15, 1995, ground-water discharge to streams in water year 1995, and residence times of ground water in different parts of the flow system that were estimated in a separate but related study. Large amounts of ground water were pumped from 1977 through 1980 from the Sea-level aquifer on Naval Submarine Base Bangor to enable the construction of an off-shore drydock. Records of the flow-system responses to the applied stresses were used to help calibrate the model. Errors in the calibrated model were significant. The poor agreement between simulated and measured values could be improved by making many local changes to hydraulic parameters but these changes were not supported by other data. Model errors may have resulted in errors in the simulated effects of ground-water pumping alternatives.

Larval development and settling of Macoma balthica in a large-scale mesocosm experiment at different fCO2 levels

NASA Astrophysics Data System (ADS)

Jansson, A.; Lischka, S.; Boxhammer, T.; Schulz, K. G.; Norkko, J.

2015-12-01

Anthropogenic carbon dioxide (CO2) emissions are causing severe changes in the global inorganic carbon balance of the oceans. Associated ocean acidification is expected to impose a major threat to marine ecosystems worldwide, and it is also expected to be amplified in the Baltic Sea where the system is already at present exposed to relatively large natural seasonal and diel pH fluctuations. The response of organisms to future ocean acidification has primarily been studied in single-species experiments, whereas the knowledge of community-wide responses is still limited. To study responses of the Baltic Sea pelagic community to a range of future CO2-scenarios, six ∼ 55 m3 pelagic mesocosms were deployed in the northern Baltic Sea in June 2012. In this specific study we focused on the tolerance, development and subsequent settlement process of the larvae of the benthic key-species Macoma balthica when exposed to different levels of future CO2. We found that the settling of M. balthica was delayed along the increasing CO2 gradient of the mesocosms. Also, when exposed to increasing CO2 levels larvae settled at a larger size, indicating a developmental delay. With on-going climate change, both the frequency and extent of regularly occurring high CO2 conditions is likely to increase, and a permanent pH decrease will likely occur. The strong impact of increasing CO2 levels on early-stage bivalves is alarming as these stages are crucial for sustaining viable populations, and a failure in their recruitment would ultimately lead to negative effects on the population.

Uprated OMS Engine Status-Sea Level Testing Results

NASA Technical Reports Server (NTRS)

Bertolino, J. D.; Boyd, W. C.

1990-01-01

The current Space Shuttle Orbital Maneuvering Engine (OME) is pressure fed, utilizing storable propellants. Performance uprating of this engine, through the use of a gas generator driven turbopump to increase operating pressure, is being pursued by the NASA Johnson Space Center (JSC). Component level design, fabrication, and test activities for this engine system have been on-going since 1984. More recently, a complete engine designated the Integrated Component Test Bed (ICTB), was tested at sea level conditions by Aerojet. A description of the test hardware and results of the sea level test program are presented. These results, which include the test condition operating envelope and projected performance at altitude conditions, confirm the capability of the selected Uprated OME (UOME) configuration to meet or exceed performance and operational requirements. Engine flexibility, demonstrated through testing at two different operational mixture ratios, along with a summary of projected Space Shuttle performance enhancements using the UOME, are discussed. Planned future activities, including ICTB tests at simulated altitude conditions, and recommendations for further engine development, are also discussed.

Near-field sea-level variability in northwest Europe and ice sheet stability during the last interglacial

NASA Astrophysics Data System (ADS)

Long, A. J.; Barlow, N. L. M.; Busschers, F. S.; Cohen, K. M.; Gehrels, W. R.; Wake, L. M.

2015-10-01

Global sea level during the Last Interglacial (LIG, Marine Isotope Sub-stage 5e) peaked between c. 5.5 and 9 m above present, implying significant melt from Greenland and Antarctica. Relative sea level (RSL) observations from several far- and intermediate-field sites suggest abrupt fluctuations or jumps in RSL during the LIG highstand that require one or more episodes of ice-sheet collapse and regrowth. Such events should be manifest as unique sea-level fingerprints, recorded in far-, intermediate- and near-field sites depending on the source(s) of ice-mass change involved. To date, though, no coherent evidence of such fluctuations has been reported from near-field RSL studies in northwest Europe. This is an important problem because RSL fluctuations during the LIG are portrayed as warning signs for how polar ice sheets may behave in a future, warmer than present, world. Here we review the evidence for RSL change during the LIG using stratigraphic data from the best resolved highstand records that exist in the near-field of northwest Europe, from a range of settings that include lagoonal, shallow marine, tidal flat, salt marsh and brackish-water fluviatile environments. Consideration of previously published stratigraphic records from two sites in the Eemian coastal-marine embayment that existed in the central Netherlands, yields no clear indications for abrupt RSL change during the attainment of the near-field highstand. Nor do we find any such indications common to other records from countries bordering the North Sea, the Baltic Sea and the White Sea. Two modelling experiments that explore the global signal of hypothetical sea-level oscillations caused by partial collapse and regrowth of either the Greenland or Antarctic LIG ice-sheet, show that the North Sea region is relatively insensitive to mass changes sourced from Greenland but should clearly register events with an Antarctic origin, especially those that occur late in the LIG. The lack of evidence for abrupt sea-level fluctuations at this time in northwest Europe concurs with a lack of clear near-field evidence for ice sheet collapse.

Future Reef Growth Can Mitigate Physical Impacts of Sea-Level Rise on Atoll Islands

NASA Astrophysics Data System (ADS)

Beetham, Edward; Kench, Paul S.; Popinet, Stéphane

2017-10-01

We present new detail on how future sea-level rise (SLR) will modify nonlinear wave transformation processes, shoreline wave energy, and wave driven flooding on atoll islands. Frequent and destructive wave inundation is a primary climate-change hazard that may render atoll islands uninhabitable in the near future. However, limited research has examined the physical vulnerability of atoll islands to future SLR and sparse information are available to implement process-based coastal management on coral reef environments. We utilize a field-verified numerical model capable of resolving all nonlinear wave transformation processes to simulate how future SLR will modify wave dissipation and overtopping on Funafuti Atoll, Tuvalu, accounting for static and accretionary reef adjustment morphologies. Results show that future SLR coupled with a static reef morphology will not only increase shoreline wave energy and overtopping but will fundamentally alter the spectral composition of shoreline energy by decreasing the contemporary influence of low-frequency infragravity waves. "Business-as-usual" emissions (RCP 8.5) will result in annual wave overtopping on Funafuti Atoll by 2030, with overtopping at high tide under mean wave conditions occurring from 2090. Comparatively, vertical reef accretion in response to SLR will prevent any significant increase in shoreline wave energy and mitigate wave driven flooding volume by 72%. Our results provide the first quantitative assessment of how effective future reef accretion can be at mitigating SLR-associated flooding on atoll islands and endorse active reef conservation and restoration for future coastal protection.

Understanding Sea Level Changes

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.

2004-01-01

Today more than 100 million people worldwide live on coastlines within one meter of mean sea level; any short-term or long-term sea level change relative to vertical ground motion is of great societal and economic concern. As palm-environment and historical data have clearly indicated the existence and prevalence of such changes in the past, new scientific information regarding to the nature and causes and a prediction capability are of utmost importance for the future. The 10-20 cm global sea-level rise recorded over the last century has been broadly attributed to two effects: (1) the steric effect (thermal expansion and salinity-density compensation of sea water) following global climate; (2) mass-budget changes due to a number of competing geophysical and hydrological processes in the Earth-atmosphere-hydrosphere-cryosphere system, including water exchange from polar ice sheets and mountain glaciers to the ocean, atmospheric water vapor and land hydrological variations, and anthropogenic effects such as water impoundment in artificial reservoirs and extraction of groundwater, all superimposed on the vertical motions of solid Earth due to tectonics, rebound of the mantle from past and present deglaciation, and other local ground motions. As remote-sensing tools, a number of space geodetic measurements of sea surface topography (e.g., TOPEX/Poseidon, Jason), ice mass (e.g., ICESat), time-variable gravity (e.g. GRACE), and ground motions (SLR, VLBI, GPS, InSAR, Laser altimetry, etc.) become directly relevant. Understanding sea level changes "anywhere, anytime" in a well-defined terrestrial reference frame in terms of climate change and interactions among ice masses, oceans, and the solid Earth, and being able to predict them, emerge as one of the scientific challenges in the Solid Earth Science Working Group (SESWG, 2003) conclusions.

Development 3D model of adaptation of the Azerbaijan coastal zone at the various levels of Caspian Sea

NASA Astrophysics Data System (ADS)

Mammadov, Ramiz

2013-04-01

The most characteristic feature of the Caspian Sea which difference it on relation other seas is its periodical fluctuating in its level. In many coastal regions of the world the problem of influence of change of a sea level on activities of the human is a problem of the long-term future, but in region of Caspian Sea, especially in its Azerbaijan sector, it is already actual. Also experience accumulated here, can be use at the decision of problems of optimization of wildlife management in conditions of significant change of a sea level as model of potential consequences of warming of a climate. Changeableness of the level of the Caspian sea over many years can be observed better on the basis of natural observations, a systematic basis of which has been put by the academician E. Lents in 1830 year in Baku coastal line. According these data in 1882 the average level has reached its level -25.2 m. the highest point over the observations, i.e. by 1.8 m. higher than today's level. The average level over 1830-1930 was about -25.83 m. In 1960 some stabilization in the level, about 28,4 meters, in 1970 was a sharp drop, in 1977 - sharp drop reached -29.00 rn. The drop over the whole period of observations totaled 3.8 m within diapason -25.2 -29.0 m. In 1978 the level of the sea began to increase and in 1995 its average yearly mark reach -26,62 rn. Intensiveness of the rise of the level ever that period totaled in average about 14 cm per year. As a result of this rise of a sea level about 800 km2 of a coastal zone it has been flooded, the ecological situation has worsened, and there were ecological refugees. The damage to a coastal zone of Azerbaijan was 2 billion USA dollars. Caspian sea also has within-year (seasonal) variability equal 32 sm and sleeve and pileup change of level. Its estimate in Azerbaijan coastal zone is 0.8-1.0 m. In the coastal zone also necessary take into height of the wave which in these coasts can be 3.0 m height. All these means that in the coastal areas at hydraulic engineering projects the sea level should be considered as multistage process, what we have considered by development of adaptation of a coastal zone The exact three-dimensional map of a coastal zone has been created. For different scenario sea levels, or example, -30.0; -29.0; -28.0; -27.0; -26.0; -25.0 and -24.0 exact coastal lines have been certain. Further maps of a vegetative cover, ground, social and economic and ecological conditions have been developed for different level and respective alterations are certain. More vulnerable coastal zone, flooded area and socio-economic damage were estimated.

The multi-millennial Antarctic commitment to future sea-level rise

NASA Astrophysics Data System (ADS)

Golledge, N. R.; Kowalewski, D. E.; Naish, T. R.; Levy, R. H.; Fogwill, C. J.; Gasson, E. G. W.

2015-10-01

Atmospheric warming is projected to increase global mean surface temperatures by 0.3 to 4.8 degrees Celsius above pre-industrial values by the end of this century. If anthropogenic emissions continue unchecked, the warming increase may reach 8-10 degrees Celsius by 2300 (ref. 2). The contribution that large ice sheets will make to sea-level rise under such warming scenarios is difficult to quantify because the equilibrium-response timescale of ice sheets is longer than those of the atmosphere or ocean. Here we use a coupled ice-sheet/ice-shelf model to show that if atmospheric warming exceeds 1.5 to 2 degrees Celsius above present, collapse of the major Antarctic ice shelves triggers a centennial- to millennial-scale response of the Antarctic ice sheet in which enhanced viscous flow produces a long-term commitment (an unstoppable contribution) to sea-level rise. Our simulations represent the response of the present-day Antarctic ice-sheet system to the oceanic and climatic changes of four representative concentration pathways (RCPs) from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We find that substantial Antarctic ice loss can be prevented only by limiting greenhouse gas emissions to RCP 2.6 levels. Higher-emissions scenarios lead to ice loss from Antarctic that will raise sea level by 0.6-3 metres by the year 2300. Our results imply that greenhouse gas emissions in the next few decades will strongly influence the long-term contribution of the Antarctic ice sheet to global sea level.

The multi-millennial Antarctic commitment to future sea-level rise.

PubMed

Golledge, N R; Kowalewski, D E; Naish, T R; Levy, R H; Fogwill, C J; Gasson, E G W

2015-10-15

Atmospheric warming is projected to increase global mean surface temperatures by 0.3 to 4.8 degrees Celsius above pre-industrial values by the end of this century. If anthropogenic emissions continue unchecked, the warming increase may reach 8-10 degrees Celsius by 2300 (ref. 2). The contribution that large ice sheets will make to sea-level rise under such warming scenarios is difficult to quantify because the equilibrium-response timescale of ice sheets is longer than those of the atmosphere or ocean. Here we use a coupled ice-sheet/ice-shelf model to show that if atmospheric warming exceeds 1.5 to 2 degrees Celsius above present, collapse of the major Antarctic ice shelves triggers a centennial- to millennial-scale response of the Antarctic ice sheet in which enhanced viscous flow produces a long-term commitment (an unstoppable contribution) to sea-level rise. Our simulations represent the response of the present-day Antarctic ice-sheet system to the oceanic and climatic changes of four representative concentration pathways (RCPs) from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We find that substantial Antarctic ice loss can be prevented only by limiting greenhouse gas emissions to RCP 2.6 levels. Higher-emissions scenarios lead to ice loss from Antarctic that will raise sea level by 0.6-3 metres by the year 2300. Our results imply that greenhouse gas emissions in the next few decades will strongly influence the long-term contribution of the Antarctic ice sheet to global sea level.

Infrastructure effects on estuarine wetlands increase their vulnerability to sea level rise

NASA Astrophysics Data System (ADS)

Rodriguez, Jose; Saco, Patricia; Sandi, Steven; Saintilan, Neil; Riccardi, Gerardo

2017-04-01

At the regional and global scales, coastal management and planning for future sea level rise scenarios is typically supported by modelling tools that predict the expected inundation extent. These tools rely on a number of simplifying assumptions that, in some cases, may result in important miscalculation of the inundation effects. One of such cases is estuarine wetlands, where vegetation strongly depends on both the magnitude and the timing of inundation. Many coastal wetlands display flow restrictions due to infrastructure or drainage works, which produce alterations to the inundation patterns that can not be captured by conventional models. In this contribution we explore the effects of flow restrictions on inundation patterns under sea level rise conditions in estuarine wetlands. We use a spatially-distributed dynamic wetland ecogeomorphological model that not only incorporates the effects of flow restrictions due to culverts, bridges and weirs as well as vegetation, but also considers that vegetation changes as a consequence of increasing inundation. We also consider the ability of vegetation to capture sediment and produce accretion. We apply our model to an estuarine wetland in Australia and show that our model predicts a much faster wetland loss due to sea level rise than conventional approaches.

High resolution climate projection of storm surge at the Venetian coast

NASA Astrophysics Data System (ADS)

Mel, R.; Sterl, A.; Lionello, P.

2013-04-01

Climate change impact on storm surge regime is of great importance for the safety and maintenance of Venice. In this study a future storm surge scenario is evaluated using new high resolution sea level pressure and wind data recently produced by EC-Earth, an Earth System Model based on the operational seasonal forecast system of the European Centre for Medium-Range Weather Forecasts (ECMWF). The study considers an ensemble of six 5 yr long simulations of the rcp45 scenario at 0.25° resolution and compares the 2094-2098 to the 2004-2008 period. EC-Earth sea level pressure and surface wind fields are used as input for a shallow water hydrodynamic model (HYPSE) which computes sea level and barotropic currents in the Adriatic Sea. Results show that a high resolution climate model is needed for producing realistic values of storm surge statistics and confirm previous studies in that they show little sensitivity of storm surge levels to climate change. However, some climate change signals are detected, such as increased persistence of high pressure conditions, an increased frequency of windless hour, and a decreased number of moderate windstorms.

Mapping Relative Sea Level Influences of the Cape Fear Arch in southern North Carolina

NASA Astrophysics Data System (ADS)

Hawkes, A.; Kemp, A.; Capar, P.

2017-12-01

Long-term relative sea-level (RSL) records are a necessary benchmark by which to gauge present accelerated rates of sea-level rise, future sea-level predictions, and their implications to the coastal zone. The east coast of the United States functions as a significant region of latitudinal RSL variability due to the continuous recovery of land from the deglaciation of the Laurentide Ice Sheet since the Last Glacial Maximum. Differential glacial isostatic adjustment (GIA) along the coastline has caused higher rates of subsidence in areas around the former forbulge maxima near New Jersey and Delaware and lower rates to the north and south of this maxima. However, the coast between southern North Carolina and northern South Carolina is experiencing a slower rate of RSL rise then is seen in reconstructed GIA latitudinal trends along the U.S. east coast. It was thought that this could have been attributed to non-isostatic, long-term tectonic processes causing less GIA subsidence of the lithosphere within the region impacted by uplift from the Cape Fear Arch (CFA), an underlying crystalline basement high. A recent study suggests that RSL rise is slower around the CFA than areas to the north and south due to suggested CFA uplift rates of 0.24+0.15mm a-1. An absence of RSL records for 200km north of the CFA make mapping of its influence difficult. Additional RSL records to the north of the CFA allow for a better understanding of the asymmetrical distribution in the rate of RSL rise in this region. Because the distribution in the rate of RSLR between records is not linear it is important for these low-lying coastal communities to better understand their risk to future RSLR.

Challenges faced by ice sheet projections: lessons from the SeaRISE effort

NASA Astrophysics Data System (ADS)

Nowicki, S.

2013-12-01

Projecting the future evolution of the Greenland and Antarctic ice sheets is a problem of enormous societal importance, as ice sheet influence our future sea levels. This crucial issue is however a non trivial task, as demonstrated by the Sea level Response to Ice Sheet Evolution (SeaRISE) effort: prescribing simple external forcings to a group of ice sheet models results in a spread in responses. Understanding the source of the diversity in the model results is therefore crucial in order to reduce the uncertainty in the projection. Just as in any future climate simulation, the analysis presented here demonstrates that the model spread in the SeaRISE effort is due to a number of factors. First is the problem of obtaining an initial configuration for the projection. The two commonly used methods, interglacial spin-up or data assimilation, have both advantages and drawbacks, and will affect the determination of fields that cannot be measured (such as basal slipperiness). Second is the uncertainty in actual observations, which includes but is not limited to surface mass balance, basal topography, ice thickness, and surface velocities. An additional issue with these observations is that they can be transient quantities which are not measured at the same time, but ice sheet models require them to be simultaneous. Third is the uncertainty in the models' physics and discretization, which is limited by our understanding (or lack of understanding) of crucial processes that often occur at subgrid scale relative to the resolution used by continental ice sheet models, and thus require parameterization. Grounding line migration and sliding laws are such an example. Fourth is the determination of the future forcing scenarios and their implementation as the external forcing. Unfortunately, as demonstrated in this analysis, all ice sheet models face these limitations to some degree, so that it is extremely difficult to identify a set of models and projections that should be trusted in preference to others. One model might be more suitable for assessing the impact of a warmer atmosphere because of its initialization procedure, but its deficiencies in capturing grounding line migration, for example, might make its projections for oceanic forcing unreliable. More work is thus required to evaluate individual ice sheet models' skills in projection, but this crucial and challenging task is left for future studies.

Future aerosol concentrations in Europe: Effects of changing meteorology and emissions

NASA Astrophysics Data System (ADS)

Coleman, Liz; Martin, Damien; Radalescu, Razvan; O'Dowd, Colin

2013-05-01

The ambient particulate matter concentrations are assessed using annual simulations for model validation period 2006, and for future time-slice years 2030, 2050 and 2100 under RCP scenario 6.0. Meteorological initial and boundary conditions are procured from ECHAM5-HAMMOC global simulations. The contribution of natural and anthropogenic processes to aerosol concentrations are assessed with particular emphasis on accumulation mode sea salt, organic enrichment thereof and future levels of secondary organic aerosol from isoprene.

Persistent cold air outbreaks over North America in a warming climate

DOE PAGES

Gao, Yang; Leung, L. Ruby; Lu, Jian; ...

2015-03-30

This study examines future changes of cold air outbreaks (CAO) using a multi-model ensemble of global climate simulations from the Coupled Model Intercomparison Project Phase 5 as well as regional high resolution climate simulations. In the future, while robust decrease of CAO duration dominates in most regions, the magnitude of decrease over northwestern U.S. is much smaller than the surrounding regions. We identified statistically significant increases in sea level pressure during CAO events centering over Yukon, Alaska, and Gulf of Alaska that advects continental cold air to northwestern U.S., leading to blocking and CAO events. Changes in large scale circulationmore » contribute to about 50% of the enhanced sea level pressure anomaly conducive to CAO in northwestern U.S. in the future. High resolution regional simulations revealed potential contributions of increased existing snowpack to increased CAO in the near future over the Rocky Mountain, southwestern U.S., and Great Lakes areas through surface albedo effects, despite winter mean snow water equivalent decreases in the future. Overall, the multi-model projections emphasize that cold extremes do not completely disappear in a warming climate. Concomitant with the relatively smaller reduction in CAO events in northwestern U.S., the top 5 most extreme CAO events may still occur in the future, and wind chill warning will continue to have societal impacts in that region.« less

Behavioral responses of Atlantic cod to sea temperature changes.

PubMed

Freitas, Carla; Olsen, Esben Moland; Moland, Even; Ciannelli, Lorenzo; Knutsen, Halvor

2015-05-01

Understanding responses of marine species to temperature variability is essential to predict impacts of future climate change in the oceans. Most ectotherms are expected to adjust their behavior to avoid extreme temperatures and minimize acute changes in body temperature. However, measuring such behavioral plasticity in the wild is challenging. Combining 4 years of telemetry-derived behavioral data on juvenile and adult (30-80 cm) Atlantic cod (Gadus morhua), and in situ ocean temperature measurements, we found a significant effect of sea temperature on cod depth use and activity level in coastal Skagerrak. During summer, cod were found in deeper waters when sea surface temperature increased. Further, this effect of temperature was stronger on larger cod. Diel vertical migration, which consists in a nighttime rise to shallow feeding habitats, was stronger among smaller cod. As surface temperature increased beyond ∼15°C, their vertical migration was limited to deeper waters. In addition to larger diel vertical migrations, smaller cod were more active and travelled larger distances compared to larger specimens. Cold temperatures during winter tended, however, to reduce the magnitude of diel vertical migrations, as well as the activity level and distance moved by those smaller individuals. Our findings suggest that future and ongoing rises in sea surface temperature may increasingly deprive cod in this region from shallow feeding areas during summer, which may be detrimental for local populations of the species.

Behavioral responses of Atlantic cod to sea temperature changes

PubMed Central

Freitas, Carla; Olsen, Esben Moland; Moland, Even; Ciannelli, Lorenzo; Knutsen, Halvor

2015-01-01

Understanding responses of marine species to temperature variability is essential to predict impacts of future climate change in the oceans. Most ectotherms are expected to adjust their behavior to avoid extreme temperatures and minimize acute changes in body temperature. However, measuring such behavioral plasticity in the wild is challenging. Combining 4 years of telemetry-derived behavioral data on juvenile and adult (30–80 cm) Atlantic cod (Gadus morhua), and in situ ocean temperature measurements, we found a significant effect of sea temperature on cod depth use and activity level in coastal Skagerrak. During summer, cod were found in deeper waters when sea surface temperature increased. Further, this effect of temperature was stronger on larger cod. Diel vertical migration, which consists in a nighttime rise to shallow feeding habitats, was stronger among smaller cod. As surface temperature increased beyond ∼15°C, their vertical migration was limited to deeper waters. In addition to larger diel vertical migrations, smaller cod were more active and travelled larger distances compared to larger specimens. Cold temperatures during winter tended, however, to reduce the magnitude of diel vertical migrations, as well as the activity level and distance moved by those smaller individuals. Our findings suggest that future and ongoing rises in sea surface temperature may increasingly deprive cod in this region from shallow feeding areas during summer, which may be detrimental for local populations of the species. PMID:26045957

Modeling Storm-Induced Inundation on the Yukon-Kuskokwim Delta for Present and Future Climates

NASA Astrophysics Data System (ADS)

Ravens, T. M.; Allen, J.

2012-12-01

The Yukon-Kuskokwim (YK) Delta is a large delta on the west coast of Alaska and one of the few remaining deltas that is largely free of anthropogenic impacts. The delta hosts a wide-range of nesting birds including the endangered Spectacled Eider. The delta plain, with an elevation of about 2 m (m.s.l.) - and an average tidal range of 2.7 m - is subject to frequent inundation by storm surges originating from the adjacent Bering Sea. Here, we report on our efforts to validate a storm-surge modeling system consisting of a course-grid ADCIRC model covering the Bering and Chukchi Seas and a Delft3D fine-grid model of the southern YK Delta. The storm surge models are validated based on measured water levels from 2007-2010 and using satellite observations of inundation due to large storms in 2005 and 2006. About 10 storms over the past 30 years are modeled. Based on model output, we computed a spatially distributed inundation index which is a time-integral of water level throughout the fine-grid model domain from individual storms and from the 30 year period. In order to examine the change in inundation in future climates, the models of the 30 year period were re-run assuming a 1 and 2 meter sea level rise. The impact of climate change on inundation frequency and intensity - using the inundation index - is reported. Future work will relate the present and projected inundation index to ecological parameters such as bird-nest concentration and vegetation type.

More than 70 years of continuous sea level records on the Santander Bay.

NASA Astrophysics Data System (ADS)

Lavín, Alicia; Tel, Elena; Molinero, Joaquin; Rodriguez, Carmen

2017-04-01

The knowledge of sea level height is important for many different sectors as navigation, transport, building infrastructures, tourism, or maritime sports, between others. Tides are mainly composed of an astronomical part and a meteorological one. Sometimes, their joined action is the responsible of extreme behaviors in the sea level. Influence of pressure differences, as well as related winds, is important in the behavior of sea level to analyze. The first system for reading the sea level was a tide board attached at the pier. In Spain the first modern tide gauge was installed in the Port of Alicante, Mediterranean Sea, in 1873 depending of the National Geographic Institute (IGN). Just the following year, a similar tide gauge was installed at the entrance of the Santander Bay. "La Magdalena" tide gauge was working during two periods 1876-1928 and 1963-1975. Together with Cádiz, the IGN tide gauges were used to determinate the national datum for terrestrial cartography. The Spanish Institute of Oceanography (IEO) tide gauge network was initiated in 1943 with the installation of tide gauges along the Spanish coast. One of them was located in Santander and has been working since then. At the beginning it was a float tide gauge connected to a graphical continuous recorder. Nowadays, it also has a digital encoder and a remote connection that allow using the recorded data for operational purposes. Later a Radar system was added. This tide gauge is referred to the Tide Gauge Zero and also calibrated to a benchmark in order to have a unique reference. This high quality sea level information is required for international and regional research activities, as Global Sea Level Observing System (GLOSS). In particular, long time series are widely used for climate change detection. The sea level long term variability studies require a very good quality data focus in the reference of the data along the whole period and also it will be more precisely if we can remove the crustal movements by monitoring the tide gauge benchmark. Increase in sea level detected in the Santander tide gauge is more than 2 mm/year. Annual and semi-annual cycles are detected in the monthly mean sea level. The amplitude of the annual cycle is 30 mm. and the semiannual 21 mm. Due to the good correlation between the NAO index and the monthly mean sea level we can assume that an important part of these cycles corresponds to the meteorological influence. The historical original records on paper are also digitalized images in order to avoid loses by paper degrading, facilitate the access to them, and in the future, keep a higher frequency record for systematic studies of extreme events.

Interferometric Synthetic Aperture Radar to capture spatial variability of local land-based subsidence

NASA Astrophysics Data System (ADS)

Bekaert, D. P.; Hamlington, B.; Buzzanga, B. A.; Jones, C. E.

2017-12-01

The rate of relative sea level rise results from a combination of land subsidence and rising seas associated with global warming on long timescales and exacerbated by shifts in ocean dynamics on shorter timescales. An understanding of the current-day magnitude of each component is needed to create accurate projections of future relative sea level rise upon which to base planning efforts. Current day land-based subsidence rates derived from GPS often lack the spatial resolution to capture the local spatial variability needed when assessing the impact of relative sea-level rise. Interferometric Synthetic Aperture Radar (InSAR) is an attractive technique that has the potential to provide a measurement every 20-30m when good signal coherence is maintained. In practice, coastal regions are challenging for InSAR due to variable vegetation cover and soil moisture, which can be in part mitigated by applying advanced time-series InSAR techniques. After applying time-series InSAR, derived rates need to be combined with GPS to tie relative subsidence rates into a geodetic reference frame. Given the need to make projections of relative sea-level rise it is particularly important to propagate all uncertainties during the different processing stages. Here we provide results from ALOS and Sentinel-1 over Hampton Roads area in the Chesapeake Bay region, which is experiencing one of the highest rates of relative sea level rise on the Atlantic coast of the United States. Although the current derived subsidence rates have large uncertainties, it is expected that this will improve with the decadal observations from Sentinel-1.

Anticipating Future Sea Level Rise and Coastal Storms in New York City (Invited)

NASA Astrophysics Data System (ADS)

Horton, R. M.; Gornitz, V.; Bader, D.; Little, C. M.; Oppenheimer, M.; Patrick, L.; Orton, P. M.; Rosenzweig, C.; Solecki, W.

2013-12-01

Hurricane Sandy caused 43 fatalities in New York City and 19 billion in damages. Mayor Michael Bloomberg responded by convening the second New York City Panel on Climate Change (NPCC2), to provide up-to-date climate information for the City's Special Initiative for Rebuilding and Resiliency (SIRR). The Mayor's proposed 20 billion plan aims to strengthen the City's resilience to coastal inundation. Accordingly, the NPCC2 scientific and technical support team generated a suite of temperature, precipitation, and sea level rise and extreme event projections through the 2050s. The NPCC2 sea level rise projections include contributions from ocean thermal expansion, dynamic changes in sea surface height, mass changes in glaciers, ice caps, and ice sheets, and land water storage. Local sea level changes induced by changes in ice mass include isostatic, gravitational, and rotational effects. Results are derived from CMIP5 model-based outputs, expert judgment, and literature surveys. Sea level at the Battery, lower Manhattan, is projected to rise by 7-31 in (17.8-78.7cm) by the 2050s relative to 2000-2004 (10 to 90 percentile). As a result, flood heights above NAVD88 for the 100-year storm (stillwater plus waves) would rise from 15.0 ft (0.71 m) in the 2000s to 15.6-17.6 ft (4.8-5.4 m) by the 2050s (10-90 percentile). The annual chance of today's 100-year flood would increase from 1 to 1.4-5.0 percent by the 2050s.

Elevated CO2 stimulates marsh elevation gain, counterbalancing sea-level rise

USGS Publications Warehouse

Langley, J.A.; McKee, K.L.; Cahoon, D.R.; Cherry, J.A.; Megonigala, J.P.

2009-01-01

Tidal wetlands experiencing increased rates of sea-level rise (SLR) must increase rates of soil elevation gain to avoid permanent conversion to open water. The maximal rate of SLR that these ecosystems can tolerate depends partly on mineral sediment deposition, but the accumulation of organic matter is equally important for many wetlands. Plant productivity drives organic matter dynamics and is sensitive to global change factors, such as rising atmospheric CO2 concentration. It remains unknown how global change will influence organic mechanisms that determine future tidal wetland viability. Here, we present experimental evidence that plant response to elevated atmospheric [CO2] stimulates biogenic mechanisms of elevation gain in a brackish marsh. Elevated CO2 (ambient + 340 ppm) accelerated soil elevation gain by 3.9 mm yr−1in this 2-year field study, an effect mediated by stimulation of below-ground plant productivity. Further, a companion greenhouse experiment revealed that the CO2 effect was enhanced under salinity and flooding conditions likely to accompany future SLR. Our results indicate that by stimulating biogenic contributions to marsh elevation, increases in the greenhouse gas, CO2, may paradoxically aid some coastal wetlands in counterbalancing rising seas.

Elevated CO2 stimulates marsh elevation gain, counterbalancing sea-level rise.

PubMed

Langley, J Adam; McKee, Karen L; Cahoon, Donald R; Cherry, Julia A; Megonigal, J Patrick

2009-04-14

Tidal wetlands experiencing increased rates of sea-level rise (SLR) must increase rates of soil elevation gain to avoid permanent conversion to open water. The maximal rate of SLR that these ecosystems can tolerate depends partly on mineral sediment deposition, but the accumulation of organic matter is equally important for many wetlands. Plant productivity drives organic matter dynamics and is sensitive to global change factors, such as rising atmospheric CO(2) concentration. It remains unknown how global change will influence organic mechanisms that determine future tidal wetland viability. Here, we present experimental evidence that plant response to elevated atmospheric [CO(2)] stimulates biogenic mechanisms of elevation gain in a brackish marsh. Elevated CO(2) (ambient + 340 ppm) accelerated soil elevation gain by 3.9 mm yr(-1) in this 2-year field study, an effect mediated by stimulation of below-ground plant productivity. Further, a companion greenhouse experiment revealed that the CO(2) effect was enhanced under salinity and flooding conditions likely to accompany future SLR. Our results indicate that by stimulating biogenic contributions to marsh elevation, increases in the greenhouse gas, CO(2), may paradoxically aid some coastal wetlands in counterbalancing rising seas.

Elevated CO2 stimulates marsh elevation gain, counterbalancing sea-level rise

PubMed Central

Langley, J. Adam; McKee, Karen L.; Cahoon, Donald R.; Cherry, Julia A.; Megonigal, J. Patrick

2009-01-01

Tidal wetlands experiencing increased rates of sea-level rise (SLR) must increase rates of soil elevation gain to avoid permanent conversion to open water. The maximal rate of SLR that these ecosystems can tolerate depends partly on mineral sediment deposition, but the accumulation of organic matter is equally important for many wetlands. Plant productivity drives organic matter dynamics and is sensitive to global change factors, such as rising atmospheric CO2 concentration. It remains unknown how global change will influence organic mechanisms that determine future tidal wetland viability. Here, we present experimental evidence that plant response to elevated atmospheric [CO2] stimulates biogenic mechanisms of elevation gain in a brackish marsh. Elevated CO2 (ambient + 340 ppm) accelerated soil elevation gain by 3.9 mm yr−1 in this 2-year field study, an effect mediated by stimulation of below-ground plant productivity. Further, a companion greenhouse experiment revealed that the CO2 effect was enhanced under salinity and flooding conditions likely to accompany future SLR. Our results indicate that by stimulating biogenic contributions to marsh elevation, increases in the greenhouse gas, CO2, may paradoxically aid some coastal wetlands in counterbalancing rising seas. PMID:19325121

Projected atoll shoreline and run-up changes in response to sea-level rise and varying large wave conditions at Wake and Midway Atolls, Northwestern Hawaiian Islands

USGS Publications Warehouse

Shope, James B.; Storlazzi, Curt; Hoeke, Ron

2017-01-01

Atoll islands are dynamic features that respond to seasonal alterations in wave conditions and sea level. It is unclear how shoreline wave run-up and erosion patterns along these low elevation islands will respond to projected sea-level rise (SLR) and changes in wave climate over the next century, hindering communities' preparation for the future. To elucidate how these processes may respond to climate change, extreme boreal winter and summer wave conditions under future sea-level rise (SLR) and wave climate scenarios were simulated at two atolls, Wake and Midway, using a shallow-water hydrodynamic model. Nearshore wave conditions were used to compute the potential longshore sediment flux along island shorelines via the CERC empirical formula and wave-driven erosion was calculated as the divergence of the longshore drift; run-up and the locations where the run-up exceed the berm elevation were also determined. SLR is projected to predominantly drive future island morphological change and flooding. Seaward shorelines (i.e., ocean fronted shorelines directly facing incident wave energy) were projected to experience greater erosion and flooding with SLR and in hypothetical scenarios where changes to deep water wave directions were altered, as informed by previous climate change forced Pacific wave modeling efforts. These changes caused nearshore waves to become more shore-normal, increasing wave attack along previously protected shorelines. With SLR, leeward shorelines (i.e., an ocean facing shoreline but sheltered from incident wave energy) became more accretive on windward islands and marginally more erosive along leeward islands. These shorelines became more accretionary and subject to more flooding with nearshore waves becoming more shore-normal. Lagoon shorelines demonstrated the greatest SLR-driven increase in erosion and run-up. They exhibited the greatest relative change with increasing wave heights where both erosion and run-up magnitudes increased. Wider reef flat-fronted seaward shorelines became more accretive as all oceanographic forcing parameters increased in magnitude and exhibited large run-up increases following increasing wave heights. Island end shorelines became subject to increased flooding, erosion at Wake, and accretion at Midway with SLR. Under future conditions, windward and leeward islands are projected to become thinner as ocean facing and lagoonal shorelines erode, with leeward islands becoming more elongate. Island shorelines will change dramatically over the next century as SLR and altered wave climates drive new erosional regimes. It is vital to the sustainability of island communities that the relative magnitudes of these effects are addressed when planning for projected future climates.

Projected atoll shoreline and run-up changes in response to sea-level rise and varying large wave conditions at Wake and Midway Atolls, Northwestern Hawaiian Islands

NASA Astrophysics Data System (ADS)

Shope, James B.; Storlazzi, Curt D.; Hoeke, Ron K.

2017-10-01

Atoll islands are dynamic features that respond to seasonal alterations in wave conditions and sea level. It is unclear how shoreline wave run-up and erosion patterns along these low elevation islands will respond to projected sea-level rise (SLR) and changes in wave climate over the next century, hindering communities' preparation for the future. To elucidate how these processes may respond to climate change, extreme boreal winter and summer wave conditions under future sea-level rise (SLR) and wave climate scenarios were simulated at two atolls, Wake and Midway, using a shallow-water hydrodynamic model. Nearshore wave conditions were used to compute the potential longshore sediment flux along island shorelines via the CERC empirical formula and wave-driven erosion was calculated as the divergence of the longshore drift; run-up and the locations where the run-up exceed the berm elevation were also determined. SLR is projected to predominantly drive future island morphological change and flooding. Seaward shorelines (i.e., ocean fronted shorelines directly facing incident wave energy) were projected to experience greater erosion and flooding with SLR and in hypothetical scenarios where changes to deep water wave directions were altered, as informed by previous climate change forced Pacific wave modeling efforts. These changes caused nearshore waves to become more shore-normal, increasing wave attack along previously protected shorelines. With SLR, leeward shorelines (i.e., an ocean facing shoreline but sheltered from incident wave energy) became more accretive on windward islands and marginally more erosive along leeward islands. These shorelines became more accretionary and subject to more flooding with nearshore waves becoming more shore-normal. Lagoon shorelines demonstrated the greatest SLR-driven increase in erosion and run-up. They exhibited the greatest relative change with increasing wave heights where both erosion and run-up magnitudes increased. Wider reef flat-fronted seaward shorelines became more accretive as all oceanographic forcing parameters increased in magnitude and exhibited large run-up increases following increasing wave heights. Island end shorelines became subject to increased flooding, erosion at Wake, and accretion at Midway with SLR. Under future conditions, windward and leeward islands are projected to become thinner as ocean facing and lagoonal shorelines erode, with leeward islands becoming more elongate. Island shorelines will change dramatically over the next century as SLR and altered wave climates drive new erosional regimes. It is vital to the sustainability of island communities that the relative magnitudes of these effects are addressed when planning for projected future climates.

Responding to climate risks in South Florida: New tools for adaptive water management collaboration between researchers and practitioners.

NASA Astrophysics Data System (ADS)

Treuer, G.

2017-12-01

South Florida's vulnerability to sea level rise has brought attention and research funding to the region. Scientists have demonstrated that existing flood control, water supply, and water quality challenges will be made more difficult by sea level rise. Investing in adaptation and efficiency can help reduce the region's exposure to climate change threats. However, local governments and agencies struggle to act. Suggestions for further collaboration between practitioners and researchers are presented, drawing from the results of research on homeowner risk perception, water supply management, and sea level rise adaptive stormwater investments in the Miami area. Choice Flow, an online platform for creating immersive simulations that track decision making and information gathering, was used to help 348 South Florida homeowners experience 35 years (18 inches) of sea level rise in 20 minutes. It found that there is a window of opportunity for local governments to act. Over 70% of homeowners were willing to support higher taxes to pay for adaptation investments now and in the future. And while most were not worried enough about sea level rise now they became increasingly willing to move out of the region as sea levels rose. Simulations like this could enable cities like Miami Beach pre-test new technologies and policies, e.g. new building standards or stormwater technology, which help reduce flood risk but often inspire opposition from stakeholders who perceive them as a threat. Additionally, academic researchers can collaborate with practitioners to understand how policy transitions, necessary for adaptive water management, occur over time and across jurisdictions. A data-narrative of the recent shift towards sustainable water supply in Miami-Dade County, developed in consultation with utility staff, is presented as an example. It provides a basis for comparison with other communities and a tool for entrepreneurial practitioners to advocate for conservation as a means of reducing vulnerability to sea level rise.

Losing ground - scenarios of land loss as consequence of shifting sediment budgets in the Mekong Delta

NASA Astrophysics Data System (ADS)

Schmitt, R. J. P.; Rubin, Z.; Kondolf, G. M.

2017-10-01

With changing climate and rising seas, proliferation of hydroelectric dams, instream sand mining, dyking of floodplains, accelerated subsidence from groundwater pumping, accelerated sea-level rise, and other anthropic impacts, it is certain that the Mekong Delta will undergo large changes in the coming decades. These changes will threaten the very existence of the landform itself. The multiplicity of compounding drivers and lack of reliable data lead to large uncertainties in forecasting changes in the sediment budget of the Mekong Delta, its morphology, and the ecosystems and human livelihoods it supports. We compile information on key drivers affecting the sediment budget of the Mekong Delta and compare them to quantify the magnitude of effects from different drivers. We develop a set of likely scenarios for the future development of these drivers and quantify implications for the future of the Mekong Delta using a simplified model of the delta's geometry. If sediment supply to the delta is nearly completely cut off, as would be the case with full buildout of planned dams and current rates of sediment mining, and with continued groundwater pumping at current rates, our model forecasts that the delta will almost completely disappear by the end of this century due to increased rates of delta subsidence and rising sea levels. While local management cannot prevent global sea level rise, model results suggest that there are important management steps that could prolong the persistence of the delta ecosystem and the livelihoods it supports, including a reduction in ground water pumping and maintaining sediment connectivity between the basin and the delta.

Collapse of the West Antarctic Ice Sheet after local destabilization of the Amundsen Basin

PubMed Central

Feldmann, Johannes; Levermann, Anders

2015-01-01

The future evolution of the Antarctic Ice Sheet represents the largest uncertainty in sea-level projections of this and upcoming centuries. Recently, satellite observations and high-resolution simulations have suggested the initiation of an ice-sheet instability in the Amundsen Sea sector of West Antarctica, caused by the last decades’ enhanced basal ice-shelf melting. Whether this localized destabilization will yield a full discharge of marine ice from West Antarctica, associated with a global sea-level rise of more than 3 m, or whether the ice loss is limited by ice dynamics and topographic features, is unclear. Here we show that in the Parallel Ice Sheet Model, a local destabilization causes a complete disintegration of the marine ice in West Antarctica. In our simulations, at 5-km horizontal resolution, the region disequilibrates after 60 y of currently observed melt rates. Thereafter, the marine ice-sheet instability fully unfolds and is not halted by topographic features. In fact, the ice loss in Amundsen Sea sector shifts the catchment's ice divide toward the Filchner–Ronne and Ross ice shelves, which initiates grounding-line retreat there. Our simulations suggest that if a destabilization of Amundsen Sea sector has indeed been initiated, Antarctica will irrevocably contribute at least 3 m to global sea-level rise during the coming centuries to millennia. PMID:26578762

The exposure of Sydney (Australia) to earthquake-generated tsunamis, storms and sea level rise: a probabilistic multi-hazard approach

PubMed Central

Dall'Osso, F.; Dominey-Howes, D.; Moore, C.; Summerhayes, S.; Withycombe, G.

2014-01-01

Approximately 85% of Australia's population live along the coastal fringe, an area with high exposure to extreme inundations such as tsunamis. However, to date, no Probabilistic Tsunami Hazard Assessments (PTHA) that include inundation have been published for Australia. This limits the development of appropriate risk reduction measures by decision and policy makers. We describe our PTHA undertaken for the Sydney metropolitan area. Using the NOAA NCTR model MOST (Method for Splitting Tsunamis), we simulate 36 earthquake-generated tsunamis with annual probabilities of 1:100, 1:1,000 and 1:10,000, occurring under present and future predicted sea level conditions. For each tsunami scenario we generate a high-resolution inundation map of the maximum water level and flow velocity, and we calculate the exposure of buildings and critical infrastructure. Results indicate that exposure to earthquake-generated tsunamis is relatively low for present events, but increases significantly with higher sea level conditions. The probabilistic approach allowed us to undertake a comparison with an existing storm surge hazard assessment. Interestingly, the exposure to all the simulated tsunamis is significantly lower than that for the 1:100 storm surge scenarios, under the same initial sea level conditions. The results have significant implications for multi-risk and emergency management in Sydney. PMID:25492514

The exposure of Sydney (Australia) to earthquake-generated tsunamis, storms and sea level rise: a probabilistic multi-hazard approach.

PubMed

Dall'Osso, F; Dominey-Howes, D; Moore, C; Summerhayes, S; Withycombe, G

2014-12-10

Approximately 85% of Australia's population live along the coastal fringe, an area with high exposure to extreme inundations such as tsunamis. However, to date, no Probabilistic Tsunami Hazard Assessments (PTHA) that include inundation have been published for Australia. This limits the development of appropriate risk reduction measures by decision and policy makers. We describe our PTHA undertaken for the Sydney metropolitan area. Using the NOAA NCTR model MOST (Method for Splitting Tsunamis), we simulate 36 earthquake-generated tsunamis with annual probabilities of 1:100, 1:1,000 and 1:10,000, occurring under present and future predicted sea level conditions. For each tsunami scenario we generate a high-resolution inundation map of the maximum water level and flow velocity, and we calculate the exposure of buildings and critical infrastructure. Results indicate that exposure to earthquake-generated tsunamis is relatively low for present events, but increases significantly with higher sea level conditions. The probabilistic approach allowed us to undertake a comparison with an existing storm surge hazard assessment. Interestingly, the exposure to all the simulated tsunamis is significantly lower than that for the 1:100 storm surge scenarios, under the same initial sea level conditions. The results have significant implications for multi-risk and emergency management in Sydney.

A process for developing and revising a learning progression on sea level rise using learners' explanations

NASA Astrophysics Data System (ADS)

McDonald, Robert Christopher

The purpose of this study was to explore the process of developing a learning progression (LP) on constructing explanations about sea level rise. I used a learning progressions theoretical framework informed by the situated cognition learning theory. During this exploration, I explicitly described my decision-making process as I developed and revised a hypothetical learning progression. Correspondingly, my research question was: What is a process by which a hypothetical learning progression on sea level rise is developed into an empirical learning progression using learners' explanations? To answer this question, I used a qualitative descriptive single case study with multiple embedded cases (Yin, 2014) that employed analytic induction (Denzin, 1970) to analyze data collected on middle school learners (grades 6-8). Data sources included written artifacts, classroom observations, and semi-structured interviews. Additionally, I kept a researcher journal to track my thinking about the learning progression throughout the research study. Using analytic induction to analyze collected data, I developed eight analytic concepts: participant explanation structures varied widely, global warming and ice melt cause sea level rise, participants held alternative conceptions about sea level rise, participants learned about thermal expansion as a fundamental aspect of sea level rise, participants learned to incorporate authentic scientific data, participants' mental models of the ocean varied widely, sea ice melt contributes to sea level rise, and participants held vague and alternative conceptions about how pollution impacts the ocean. I started with a hypothetical learning progression, gathered empirical data via various sources (especially semi-structured interviews), revised the hypothetical learning progression in response to those data, and ended with an empirical learning progression comprising six levels of learner thinking. As a result of developing an empirically based LP, I was able to compare two learning progressions on the same topic. By comparing my learning progression with the LP in Breslyn, McGinnis, McDonald, and Hestness (2016), I was able to confirm portions of the two learning progressions and explore different possible pathways for learners to achieve progress towards upper anchors of the LPs through targeted instruction. Implications for future LP research, curriculum, instruction, assessment, and policy related to learning progressions are presented.

Sea Level Rise Drove Enhanced Coastal Erosion following the Last Glacial Maximum, Southern California, U.S.A.

NASA Astrophysics Data System (ADS)

Sharman, G.; Covault, J. A.; Stockli, D. F.; Sickmann, Z.; Malkowski, M. A.; Johnstone, S.

2017-12-01

Seacliff erosion poses a major threat to southern California coastal communities, including the propensity for episodic cliff failure and damage to residential and commercial property. Rising sea level is predicted to accelerate seacliff retreat, yet few constraints exist on how rapid sea level rise influenced coastal erosion rates in pre-modern timescales. Here we look to the geologic record in submarine fans to investigate changes in relative sediment supply from rivers and coastal erosion, the latter including seacliff retreat and bluffland erosion. To understand how sea level rise driven by past global warming impacted coastal erosion rates, we sampled modern rivers of the Peninsular Ranges and latest Pleistocene-Holocene submarine canyon-fan systems in southern California for detrital zircon U-Pb geochronology (1369 analyses from 10 samples). Modern river samples show a systematic north-south change in grain age populations broadly distributed across Cretaceous time (ca. 70-135 Ma) to a predominance of middle Cretaceous grain ages (ca. 95-115 Ma), reflecting variations in the geologic age of units within each river catchment. The Carlsbad and La Jolla submarine canyon-fan systems, deposited during sea level lowstand and highstand, respectively, exhibit detrital zircon age distributions consistent with derivation from upstream rivers, with mixing in the littoral zone. However, a sample from the Oceanside fan, deposited during rapid sea level rise at ca. 13 ka, is dominated by detrital ages that lack a local source in the northern Peninsular Ranges, including latest Cretaceous, late Jurassic, and Proterozoic ages. However, such grain ages are widespread in Paleogene sedimentary rocks that comprise the shelf and coastal area, suggesting increased sediment supply from coastal and shelf erosion. Assuming that the Oceanside sample is representative of sediment production during sea level rise, sediment mixing calculations suggest a one to two orders of magnitude increase in sediment from coastal erosion relative to river-supplied sediment. Our results thus suggest a significant increase in coastal erosion rates following the Last Glacial Maximum, highlighting the risk that future sea level rise poses to coastal communities.

Future sea-level rise from tidewater and ice-shelf tributary glaciers of the Antarctic Peninsula

NASA Astrophysics Data System (ADS)

Schannwell, Clemens; Barrand, Nicholas E.; Radić, Valentina

2016-11-01

Iceberg calving and increased ice discharge from ice-shelf tributary glaciers contribute significant amounts to global sea-level rise (SLR) from the Antarctic Peninsula (AP). Owing to ongoing ice dynamical changes (collapse of buttressing ice shelves), these contributions have accelerated in recent years. As the AP is one of the fastest warming regions on Earth, further ice dynamical adjustment (increased ice discharge) is expected over the next two centuries. In this paper, the first regional SLR projection of the AP from both iceberg calving and increased ice discharge from ice-shelf tributary glaciers in response to ice-shelf collapse is presented. An ice-sheet model forced by temperature output from 13 global climate models (GCMs), in response to the high greenhouse gas emission scenario (RCP8.5), projects AP contribution to SLR of 28 ± 16 to 32 ± 16 mm by 2300, partitioned approximately equally between contributions from tidewater glaciers and ice-shelf tributary glaciers. In the RCP4.5 scenario, sea-level rise projections to 2300 are dominated by tidewater glaciers (∼8-18 mm). In this cooler scenario, 2.4 ± 1 mm is added to global sea levels from ice-shelf tributary drainage basins as fewer ice-shelves are projected to collapse. Sea-level projections from ice-shelf tributary glaciers are dominated by drainage basins feeding George VI Ice Shelf, accounting for ∼70% of simulated SLR. Combined total ice dynamical SLR projections to 2300 from the AP vary between 11 ± 2 and 32 ± 16 mm sea-level equivalent (SLE), depending on the emission scenario used. These simulations suggest that omission of tidewater glaciers could lead to a substantial underestimation of the ice-sheet's contribution to regional SLR.

Projections of tsunami inundation area coupled with impacts of sea level rise in Banda Aceh, Indonesia

NASA Astrophysics Data System (ADS)

Tursina, Syamsidik, Kato, Shigeru

2017-10-01

In a long term, sea level rise is anticipated to give devastating effects on Banda Aceh, as one of the coastal cities in the northern tip of Sumatra. The growth of the population and buildings in the city has come to the stage where the coastal area is vulnerable to any coastal hazard. Some public facilities and settlements have been constructed and keep expanding in the future. According to TOPEX/POSEIDON satellite images, 7 mm/year the sea level has been risen between 1992 and 2015 in this area. It is estimated that in the next 100 years, there will be 700 mm additional sea level rise which will give a setback more over to a rather flat area around the coast. This research is aim at investigating the influence of sea level rise toward the tsunami inundation on the land area particularly the impacts on Banda Aceh city. Cornell Multigrid Coupled Tsunami Model (COMCOT) simulation numerically generated tsunami propagation. Topography and bathymetry data were collected from GEBCO and updated with the available nautical chart (DISHIDROS, JICA, and field measurements). Geological movement of the underwater fault was generated using Piatanesi and Lorito of 9.15 Mw 2004 multi-fault scenario. The inundation area produced by COMCOT revealed that the inundation area was expanded to several hundred meters from the shoreline. To investigate the impacts of tsunami wave on Banda Aceh, the inundation area were digitized and analyzed with Quantum GIS spatial tools. The Quantum GIS analyzed inundations area affected by the projected tsunami. It will give a new tsunami-prone coastal area map induced by sea level rise in 100 years.

Uncertainty Quantification for Ice Sheet Science and Sea Level Projections

NASA Astrophysics Data System (ADS)

Boening, C.; Schlegel, N.; Limonadi, D.; Schodlok, M.; Seroussi, H. L.; Larour, E. Y.; Watkins, M. M.

2017-12-01

In order to better quantify uncertainties in global mean sea level rise projections and in particular upper bounds, we aim at systematically evaluating the contributions from ice sheets and potential for extreme sea level rise due to sudden ice mass loss. Here, we take advantage of established uncertainty quantification tools embedded within the Ice Sheet System Model (ISSM) as well as sensitivities to ice/ocean interactions using melt rates and melt potential derived from MITgcm/ECCO2. With the use of these tools, we conduct Monte-Carlo style sampling experiments on forward simulations of the Antarctic ice sheet, by varying internal parameters and boundary conditions of the system over both extreme and credible worst-case ranges. Uncertainty bounds for climate forcing are informed by CMIP5 ensemble precipitation and ice melt estimates for year 2100, and uncertainty bounds for ocean melt rates are derived from a suite of regional sensitivity experiments using MITgcm. Resulting statistics allow us to assess how regional uncertainty in various parameters affect model estimates of century-scale sea level rise projections. The results inform efforts to a) isolate the processes and inputs that are most responsible for determining ice sheet contribution to sea level; b) redefine uncertainty brackets for century-scale projections; and c) provide a prioritized list of measurements, along with quantitative information on spatial and temporal resolution, required for reducing uncertainty in future sea level rise projections. Results indicate that ice sheet mass loss is dependent on the spatial resolution of key boundary conditions - such as bedrock topography and melt rates at the ice-ocean interface. This work is performed at and supported by the California Institute of Technology's Jet Propulsion Laboratory. Supercomputing time is also supported through a contract with the National Aeronautics and Space Administration's Cryosphere program.

Salton Sea ecosystem monitoring and assessment plan

USGS Publications Warehouse

Case(compiler), H. L.; Boles, Jerry; Delgado, Arturo; Nguyen, Thang; Osugi, Doug; Barnum, Douglas A.; Decker, Drew; Steinberg, Steven; Steinberg, Sheila; Keene, Charles; White, Kristina; Lupo, Tom; Gen, Sheldon; Baerenklau, Ken A.

2013-01-01

The Salton Sea, California’s largest lake, provides essential habitat for several fish and wildlife species and is an important cultural and recreational resource. It has no outlet, and dissolved salts contained in the inflows concentrate in the Salton Sea through evaporation. The salinity of the Salton Sea, which is currently nearly one and a half times the salinity of ocean water, has been increasing as a result of evaporative processes and low freshwater inputs. Further reductions in inflows from water conservation, recycling, and transfers will lower the level of the Salton Sea and accelerate the rate of salinity increases, reduce the suitability of fish and wildlife habitat, and affect air quality by exposing lakebed playa that could generate dust. Legislation enacted in 2003 to implement the Quantification Settlement Agreement (QSA) stated the Legislature’s intent for the State of California to undertake the restoration of the Salton Sea ecosystem. As required by the legislation, the California Resources Agency (now California Natural Resources Agency) produced the Salton Sea Ecosystem Restoration Study and final Programmatic Environmental Impact Report (PEIR; California Resources Agency, 2007) with the stated purpose to “develop a preferred alternative by exploring alternative ways to restore important ecological functions of the Salton Sea that have existed for about 100 years.” A decision regarding a preferred alternative currently resides with the California State Legislature (Legislature), which has yet to take action. As part of efforts to identify an ecosystem restoration program for the Salton Sea, and in anticipation of direction from the Legislature, the California Department of Water Resources (DWR), California Department of Fish and Wildlife (CDFW), U.S. Bureau of Reclamation (Reclamation), and U.S. Geological Survey (USGS) established a team to develop a monitoring and assessment plan (MAP). This plan is the product of that effort. The goal of the MAP is to provide a guide for data collection, analysis, management, and reporting to inform management actions for the Salton Sea ecosystem. Monitoring activities are directed at species and habitats that could be affected by or drive future restoration activities. The MAP is not intended to be a prescriptive document. Rather, it is envisioned to be a flexible, program-level guide that articulates high-level goals and objectives, and establishes broad sideboards within which future project-level investigations and studies will be evaluated and authorized. As such, the MAP, by design, does not, for example, include detailed protocols describing how investigations will be implemented. It is anticipated that detailed study proposals will be prepared as part of an implementation plan that will include such things as specific sampling objectives, sampling schemes, and statistical and spatial limits.

Seasonal forecasting of groundwater levels in natural aquifers in the United Kingdom

NASA Astrophysics Data System (ADS)

Mackay, Jonathan; Jackson, Christopher; Pachocka, Magdalena; Brookshaw, Anca; Scaife, Adam

2014-05-01

Groundwater aquifers comprise the world's largest freshwater resource and provide resilience to climate extremes which could become more frequent under future climate changes. Prolonged dry conditions can induce groundwater drought, often characterised by significantly low groundwater levels which may persist for months to years. In contrast, lasting wet conditions can result in anomalously high groundwater levels which result in flooding, potentially at large economic cost. Using computational models to produce groundwater level forecasts allows appropriate management strategies to be considered in advance of extreme events. The majority of groundwater level forecasting studies to date use data-based models, which exploit the long response time of groundwater levels to meteorological drivers and make forecasts based only on the current state of the system. Instead, seasonal meteorological forecasts can be used to drive hydrological models and simulate groundwater levels months into the future. Such approaches have not been used in the past due to a lack of skill in these long-range forecast products. However systems such as the latest version of the Met Office Global Seasonal Forecast System (GloSea5) are now showing increased skill up to a 3-month lead time. We demonstrate the first groundwater level ensemble forecasting system using a multi-member ensemble of hindcasts from GloSea5 between 1996 and 2009 to force 21 simple lumped conceptual groundwater models covering most of the UK's major aquifers. We present the results from this hindcasting study and demonstrate that the system can be used to forecast groundwater levels with some skill up to three months into the future.

Sea ice and pollution-modulated changes in Greenland ice core methanesulfonate and bromine

NASA Astrophysics Data System (ADS)

Maselli, Olivia J.; Chellman, Nathan J.; Grieman, Mackenzie; Layman, Lawrence; McConnell, Joseph R.; Pasteris, Daniel; Rhodes, Rachael H.; Saltzman, Eric; Sigl, Michael

2017-01-01

Reconstruction of past changes in Arctic sea ice extent may be critical for understanding its future evolution. Methanesulfonate (MSA) and bromine concentrations preserved in ice cores have both been proposed as indicators of past sea ice conditions. In this study, two ice cores from central and north-eastern Greenland were analysed at sub-annual resolution for MSA (CH3SO3H) and bromine, covering the time period 1750-2010. We examine correlations between ice core MSA and the HadISST1 ICE sea ice dataset and consult back trajectories to infer the likely source regions. A strong correlation between the low-frequency MSA and bromine records during pre-industrial times indicates that both chemical species are likely linked to processes occurring on or near sea ice in the same source regions. The positive correlation between ice core MSA and bromine persists until the mid-20th century, when the acidity of Greenland ice begins to increase markedly due to increased fossil fuel emissions. After that time, MSA levels decrease as a result of declining sea ice extent but bromine levels increase. We consider several possible explanations and ultimately suggest that increased acidity, specifically nitric acid, of snow on sea ice stimulates the release of reactive Br from sea ice, resulting in increased transport and deposition on the Greenland ice sheet.

The study of the hydrological regime extreme effects of the Caspian Sea during the XX-XXI centuries

NASA Astrophysics Data System (ADS)

Yaitskaya, Natalia

2016-04-01

The Caspian Sea - the unique largest enclosed inland body of water on Earth. Significant periodic sea level fluctuations are a typical feature of the sea. In the XIX-XX centuries a number of comprehensive studies of the Caspian Sea was carried out. The results are published in the papers, monographs and climatic atlases. But a number of fundamental questions about the features of the hydrological regime of the Caspian Sea is still open: 1. How does the water circulation change during the level variations? 2. What is the effect of heterogeneity of evaporation from the water surface on the formation of the flow field in the conditions of long-term level changes? 3. How does the water salinity regime change depending on the sea level position, water circulation, river flow and different climatic influences? 4. What is the effect of extreme events (multi-hazards) (ice, storms, destruction of the coasts) on coastal infrastructure? In 2016, the project aims to study hydrological regime extreme effects of the Caspian Sea was supported by the Russian Foundation for Basic Research. Within this project all of the above problems will be solved. Geographic information system "Caspian Sea" for the storage and data processing, including a database of primary oceanographic information for the period of instrumental observations (1897-2013), cartographic database (1921-2011) and tools for multidimensional analysis of spatio-temporal information is the basis of the study. The scheme of interconnected hydrodynamic models (Caspian Sea MODel - Ocean Model - Wind wave model) was developed. The important factors are taken into account in the structure of the models: long-term and seasonal dynamics of the sea waves parameters, new long-term values of evaporation from the shallow waters areas of the Caspian Sea, water circulation. Schemes of general seasonal circulation of the Caspian Sea and the Northern Caspian at different positions of the sea level in XX-XXI centuries using interconnected models will be reconstructed. Forecast of seasonal water circulation for the most probable climate change scenarios in the future will be done. Conceptual scheme of calculations of the multi-hazards (ice storms, the destruction of the coasts) in the Caspian Sea was developed. The similar method of calculation was successfully applied to the prediction of natural hazards in the Sea of Azov. The reported study was funded by RFBR, according to the research project No.16-35-60046 mol_a_dk.

The ICESat/GLAS Instrument Operations Report. Volume 4

NASA Technical Reports Server (NTRS)

Jester, Peggy L.

2012-01-01

The Geoscience Laser Altimeter System (GLAS) was the primary instrument aboard the first ICESat spacecraft. ICESat's primary objectives are to determine the mass balance of the polar ice sheets and their contributions to global sea level change, and to obtain essential data for prediction of future changes in ice volume and sea-level. ICESat launched successfully from Vandenberg Air Force Base on January 12, 2003 23:45 UT. The ICESat science mission began in February 2003 and ended on October 11, 2009. De-orbit of the spacecraft occurred on August 30, 2010. This document focusses on the GLAS instrument operations during the ICESat mission. This document will not discuss science results.

The Irish Sea: Is it eutrophic?

NASA Astrophysics Data System (ADS)

Gowen, R. J.; Tett, P.; Kennington, K.; Mills, D. K.; Shammon, T. M.; Stewart, B. M.; Greenwood, N.; Flanagan, C.; Devlin, M.; Wither, A.

2008-01-01

The question of whether the Irish Sea is eutrophic is addressed by reviewing the evidence for anthropogenic nutrient enrichment, elevated phytoplankton production and biomass and undesirable disturbance in the context of the EU and OSPAR definitions of eutrophication. Winter concentrations of dissolved available inorganic phosphate (DAIP), nitrogen (DAIN as nitrate and nitrite) and silicate (Si) in coastal waters and concentrations of DAIP and Si in offshore waters of the Irish Sea are elevated relative to winter Celtic Sea shelf break concentrations (0.5 μM DAIP, 7.7 μM DAIN and 2.7 μM Si). Significant, negative nutrient salinity relationships and analysis of the Isle of Man nutrient time-series indicate that the elevated Irish Sea levels of DAIP and DAIN are the result of anthropogenic enrichment with highest concentrations (≈2.0 μM DAIP, 30 μM DAIN and 17 μM Si) measured in near shore eastern Irish Sea waters. Summer levels of phytoplankton chlorophyll (Chl) range from <0.1 to 11.4 mg m -3 (mean: 3.4 mg m -3) and from <0.1 to 16.4 mg m -3 (mean: 2.2 mg m -3) in coastal and offshore waters of the western Irish Sea, respectively. Offshore eastern Irish Sea summer chlorophyll levels range from 0.3 to 3.8 mg m -3 (mean: 1.8 mg m -3). Higher levels of spring (up to 43.9 mg m -3) and summer (up to 22.7 mg m -3) biomass in Liverpool Bay are attributed to nutrient enrichment. Estimates of spring and summer production in different regions of the Irish Sea are ≤194 g C m -2. The absence of: (a) oxygen depletion in near shore and open waters of the Irish Sea (except the seasonally isolated western Irish Sea bottom water); (b) trends in the frequency of Phaeocystis spp. blooms and occurrence of toxin producing algae; and (c) changes in the dominant life form of pelagic primary producers, point to a lack of undesirable disturbance and hence argue against anthropogenic eutrophication in the Irish Sea. This conclusion is discussed in the context of future trends in anthropogenic nutrient inputs.

Sea level variability influencing coastal flooding in the Swan River region, Western Australia

NASA Astrophysics Data System (ADS)

Eliot, Matt

2012-02-01

Coastal flooding refers to the incidence of high water levels produced by water level fluctuations of marine origin, rather than riverine floods. An understanding of the amplitude and frequency of high water level events is essential to foreshore management and the design of many coastal and estuarine facilities. Coastal flooding events generally determine public perception of sea level phenomena, as they are commonly associated with erosion events. This investigation has explored the nature of coastal flooding events affecting the Swan River Region, Western Australia, considering water level records at four sites in the estuary and lower river, extending from the mouth of the Swan River to 40 km upstream. The analysis examined the significance of tides, storms and mean sea level fluctuations over both seasonal and inter-annual time scales. The relative timing of these processes is significant for the enhanced or reduced frequency of coastal flooding. These variations overlie net sea level rise previously reported from the coastal Fremantle record, which is further supported by changes to the distribution of high water level events at an estuarine tidal station. Seasonally, coastal flooding events observed in the Swan River region are largely restricted to the period from May to July due to the relative phases of the annual mean sea fluctuation and biannual tidal cycle. Although significant storm surge events occur outside this period, their impact is normally reduced, as they are superimposed on lower tidal and mean sea level conditions. Over inter-annual time scales tide, storminess and mean sea level produce cycles of enhanced and depressed frequency of coastal flooding. For the Swan River region, the inter-annual tidal variation is regular, dominated by the 18.6 year lunar nodal cycle. Storminess and mean sea level variations are independent and irregular, with cycles from 3 to 10 year duration. Since 1960, these fluctuations have not occurred in phase, suggesting that recent historic records may not provide a real indication of inundation risk, exclusive of factors linked to climate change. The burst-like nature of coastal flooding incidents, with respect to frequency, has implications for both public perception and coastal management effort. The result, when combined with sea level rise, produces step-like change, with short periods of frequent coastal flooding, followed by extended, slowly varying quiescent periods. This presents challenges for coastal managers to incorporate variability into projections of future management needs, and to ensure that public and political recognition of coastal flooding hazard is not downplayed during quiet periods.

Tidal marsh susceptibility to sea-level rise: importance of local-scale models

USGS Publications Warehouse

Thorne, Karen M.; Buffington, Kevin J.; Elliott-Fisk, Deborah L.; Takekawa, John Y.

2015-01-01

Increasing concern over sea-level rise impacts to coastal tidal marsh ecosystems has led to modeling efforts to anticipate outcomes for resource management decision making. Few studies on the Pacific coast of North America have modeled sea-level rise marsh susceptibility at a scale relevant to local wildlife populations and plant communities. Here, we use a novel approach in developing an empirical sea-level rise ecological response model that can be applied to key management questions. Calculated elevation change over 13 y for a 324-ha portion of San Pablo Bay National Wildlife Refuge, California, USA, was used to represent local accretion and subsidence processes. Next, we coupled detailed plant community and elevation surveys with measured rates of inundation frequency to model marsh state changes to 2100. By grouping plant communities into low, mid, and high marsh habitats, we were able to assess wildlife species vulnerability and to better understand outcomes for habitat resiliency. Starting study-site conditions were comprised of 78% (253-ha) high marsh, 7% (30-ha) mid marsh, and 4% (18-ha) low marsh habitats, dominated by pickleweed Sarcocornia pacifica and cordgrass Spartina spp. Only under the low sea-level rise scenario (44 cm by 2100) did our models show persistence of some marsh habitats to 2100, with the area dominated by low marsh habitats. Under mid (93 cm by 2100) and high sea-level rise scenarios (166 cm by 2100), most mid and high marsh habitat was lost by 2070, with only 15% (65 ha) remaining, and a complete loss of these habitats by 2080. Low marsh habitat increased temporarily under all three sea-level rise scenarios, with the peak (286 ha) in 2070, adding habitat for the endemic endangered California Ridgway’s rail Rallus obsoletus obsoletus. Under mid and high sea-level rise scenarios, an almost complete conversion to mudflat occurred, with most of the area below mean sea level. Our modeling assumed no marsh migration upslope due to human levee and infrastructure preventing these types of processes. Other modeling efforts done for this area have projected marsh persistence to 2100, but our modeling effort with site-specific datasets allowed us to model at a finer resolution with much higher local confidence, resulting in different results for management. Our results suggest that projected sea-level rise will have significant impacts on marsh plant communities and obligate wildlife, including those already under federal and state protection. Comprehensive modeling as done here improves the potential to implement adaptive management strategies and prevent marsh habitat and wildlife loss in the future.

Diversity of terrestrial avifauna in response to distance from the shoreline of the Salton Sea

USGS Publications Warehouse

Mendelsohn, M.B.; Boarman, W.I.; Fisher, R.N.; Hathaway, S.A.

2007-01-01

Large aquatic bodies influence surrounding terrestrial ecosystems by providing water and nutrients. In arid landscapes, the increased primary productivity that results may greatly enhance vertebrate biodiversity. The Salton Sea, a large saline lake in the Colorado Desert of southern California, provides nutrients in the form of hundreds of thousands of dead fish carcasses, brine flies, and chemical compounds through windborne salt sea spray. We performed point counts for landbirds and shorebirds monthly or every other month between March 2001 and February 2002 across a sampling grid of 35 points along the west edge of Salton Sea. We found that avian diversity (numbers of species and numbers per species) was dependent on proximity to the Sea. Diversity was at a maximum nearest the shore, and was significantly lower away from the Sea's edge, at all surveyed distances up to 1 km from the shore. Cover by the dominant shrubs on the study site also corresponded to proximity to the water's edge. Whereas one may hypothesize that the avian diversity patterns are caused by these differences in vegetation structure, our data did not support this. Future studies should further investigate this potential correlation between vegetation and bird patterns. Until more is understood about the relationship between elevated avian diversity and the physical environment of the land-shore interface, our results suggest that the Sea's surface be stabilized near its present level. Future management schemes at the Salton Sea that include reductions of water sources should be carefully analyzed, so as to not jeopardize the terrestrial avifauna at this unique ecosystem. ?? 2006 Elsevier Ltd. All rights reserved.

Asynchronous behavior of the Antarctic Ice Sheet and local glaciers during and since Termination 1, Salmon Valley, Antarctica

NASA Astrophysics Data System (ADS)

Jackson, Margaret S.; Hall, Brenda L.; Denton, George H.

2018-01-01

The stability of the Antarctic Ice Sheet under future warming remains an open question with broad implications for sea-level prediction and adaptation. In particular, knowledge of whether the ice sheet has the capacity for rapid drawdown or collapse, or whether it can remain stable during periods of warming, is essential for predicting its future behavior. Here we use 55 radiocarbon dates, coupled with geomorphologic mapping, to reconstruct the timing of changes in ice extent and elevation during the last ice-age termination in Salmon Valley, adjacent to McMurdo Sound in the western Ross Sea Embayment. Results indicate that a grounded ice sheet in the Ross Sea Embayment achieved its maximum elevation and extent along the headlands of Salmon Valley at ∼18,000 yr BP, during a period of increasing temperatures and accumulation over the Antarctic continent. This ice remained at or near its maximum on the headlands near the valley mouth until after ∼14,000 yr BP. Removal of grounded Ross Sea ice from Salmon Valley was complete shortly after ∼7900 yr BP, indicating that the grounding line had retreated through southern McMurdo Sound by that time. We suggest the primary driver of Ross Sea ice removal from McMurdo Sound was marine-based, either through basal melting or calving due to sea-level rise. When combined with regional data, the Salmon Valley record suggests that this sector of the Antarctic Ice Sheet did not contribute in a significant way to deglacial meltwater pulses, such as meltwater pulse 1a. In contrast to the Ross Sea ice, our work also shows that local, independent alpine glaciers in Salmon Valley have advanced through the Holocene. Land-terminating glaciers such as these elsewhere in the region show a similar pattern, and may reflect the continued influence of increased accumulation following the termination of the last ice age.

Healthy coral reefs may assure coastal protection in face of climate change related sea level rise

NASA Astrophysics Data System (ADS)

Harris, D. L.; Rovere, A.; Parravicini, V.; Casella, E.; Canavesio, R.; Collin, A.

2016-12-01

Coral reefs are diverse ecosystems that support millions of people worldwide providing crucial services, of which, coastal protection is one of the most relevant. The efficiency of coral reefs in protecting coastlines and dissipating waves is directly linked to the cover of living corals and three dimensional reef structural complexity. Climate change and human impacts are leading to severe global reductions in live coral cover, posing serious concerns regarding the capacity of degraded reef systems in protecting tropical coastal regions. Although it is known that the loss of structurally complex reefs may lead to greater erosion of coastlines, this process has rarely been quantified and it is still unknown whether the maintenance of healthy reefs through conservation will be enough to guarantee coastal protection during rising sea levels. We show that a significant loss of wave dissipation and a subsequent increase in back-reef wave height (up to 5 times present wave height) could occur even at present sea level if living corals are lost and reef structural complexity is reduced. Yet we also show that healthy reefs, measured by structural complexity and efficiency of vertical reef accretion, may maintain their present capacity of wave dissipation even under rising sea levels. Our results indicate that the health of coral reefs and not sea level rise will be the major determinant of the coastal protection services provided by coral reefs and calls for investments into coral reef conservation to ensure the future protection of tropical coastal communities.

Assessing impacts of climate change, sea level rise, and drainage canals on saltwater intrusion to coastal aquifer

NASA Astrophysics Data System (ADS)

Rasmussen, P.; Sonnenborg, T. O.; Goncear, G.; Hinsby, K.

2012-07-01

Groundwater abstraction from coastal aquifers is vulnerable to climate change and sea level rise because both may potentially impact saltwater intrusion and hence groundwater quality depending on the hydrogeological setting. In the present study the impacts of sea level rise and changes in groundwater recharge are quantified for an island located in the Western Baltic Sea. Agricultural land dominates the western and central parts of the island, which geologically are developed as push moraine hills and a former lagoon (later wetland area) behind barrier islands to the east. The low-lying central area of the island was extensively drained and reclaimed during the second half of the 19th century. Summer cottages along the beach on the former barrier islands dominate the eastern part of the island. The main water abstraction is for holiday cottages during the summer period (June-August). The water is abstracted from 11 wells drilled to a depth of around 20 m in the upper 5-10 m of a confined chalk aquifer. Increasing chloride concentrations have been observed in several abstraction wells and in some cases the WHO drinking water standard has been exceeded. Using the modeling package MODFLOW/MT3D/SEAWAT the historical, present and future freshwater-sea water distribution is simulated. The model is calibrated against hydraulic head observations and validated against geochemical and geophysical data from new investigation wells, including borehole logs, and from an airborne transient electromagnetic survey. The impact of climate changes on saltwater intrusion is found to be sensitive to the boundary conditions of the investigated system. For the flux-controlled aquifer to the west of the drained area only changes in groundwater recharge impacts the freshwater-sea water interface whereas sea level rise do not result in increasing sea water intrusion. However, on the barrier islands to the east of the reclaimed area below which the sea is hydraulically connected to the drainage canal, and the boundary of the flow system therefore controlled, the projected changes in sea level, groundwater recharge and stage of the drainage canal all have significant impacts on saltwater intrusion and hence the chloride concentrations found in the abstraction wells.

Barrier island response to an elevated sea-level anomaly: Onslow Beach, North Carolina, USA

NASA Astrophysics Data System (ADS)

Theuerkauf, E. J.; Rodriguez, A. B.; Fegley, S. R.; Luettich, R.

2012-12-01

Variations in sea level over time scales ranging from hours to millennia influence coastal processes and evolution. At annual time scales, elevated sea-level anomalies produce coastal flooding and promote beach erosion. This study examines the coastal response of Onslow Beach, North Carolina to the summer 2009 East Coast sea-level anomaly. Onslow Beach is a 12-km-long wave-dominated barrier island with highly variable along-barrier morphology. The transgressive southern portion of the island is characterized by a narrow beach, low dunes, and multiple washover fans, while the regressive northern portion is characterized by a wide beach and continuous tall dunes. Hourly tide gauge data from adjacent NOAA stations (Beaufort and Wrightsville Beach) are used to determine the timing and extent of elevated water levels. The seasonal and longer term trends (relative sea level rise) are removed from both of the water level series and the sea-level anomaly is represented by a large residual between the observed and predicted water levels. Beach response is quantified using terrestrial laser scanning for morphology and from geoprobe cores to determine the maximum depth of erosion (MDOE). The mean high water (MHW) shoreline and dune toe are digitized from digital elevation models derived from the laser scans and analyzed using the Digital Shoreline Analysis System (DSAS). Landward (negative) movement of these contacts indicates erosion. Wave data collected from an Acoustic Wave and Current Meter (AWAC) located offshore of the southern end of Onslow Beach is used to characterize the wave regime throughout the study. Water level is elevated in the tide gauge data from June 2009 to March 2010. This sea-level anomaly corresponds with an increase in the maximum depth of erosion between 2009 and 2010. Landward movement of the MHW shoreline and the dunetoe increased during the period between September 2009 and May 2010 indicating an increase in beach erosion during the sea-level anomaly. No significant increase in wave height was observed during this period, suggesting that the increase in beach erosion resulted from the sea-level anomaly. The sites that were strongly impacted by the sea-level anomaly did not fully recover from the beach erosion and consequently experienced large amounts of erosion in response to Hurricane Irene in 2011. These results suggest that long duration (weeks to months) high water levels cause changes to the beach similar to those generally thought to occur only during large storms. Dune erosion from higher sea levels weakens a beaches defense to storms, leading to increased beach erosion and overwash if a storm occurs before the beach can recover. It is likely that similar high water events will increase in duration and magnitude with future climate change, leading to increased "fair-weather" beach erosion and priming the system for devastating hurricane impacts.

Projections of extreme water level events for atolls in the western Tropical Pacific

NASA Astrophysics Data System (ADS)

Merrifield, M. A.; Becker, J. M.; Ford, M.; Yao, Y.

2014-12-01

Conditions that lead to extreme water levels and coastal flooding are examined for atolls in the Republic of the Marshall Islands based on a recent field study of wave transformations over fringing reefs, tide gauge observations, and wave model hindcasts. Wave-driven water level extremes pose the largest threat to atoll shorelines, with coastal levels scaling as approximately one-third of the incident breaking wave height. The wave-driven coastal water level is partitioned into a mean setup, low frequency oscillations associated with cross-reef quasi-standing modes, and wind waves that reach the shore after undergoing high dissipation due to breaking and bottom friction. All three components depend on the water level over the reef; however, the sum of the components is independent of water level due to cancelling effects. Wave hindcasts suggest that wave-driven water level extremes capable of coastal flooding are infrequent events that require a peak wave event to coincide with mid- to high-tide conditions. Interannual and decadal variations in sea level do not change the frequency of these events appreciably. Future sea-level rise scenarios significantly increase the flooding threat associated with wave events, with a nearly exponential increase in flooding days per year as sea level exceeds 0.3 to 1.0 m above current levels.

Ocean-atmosphere relationships from synoptic scale to local scale in South San Francisco Bay, with implications to flood risk at NASA Ames Research Center, Silicon Valley

NASA Astrophysics Data System (ADS)

Mills, W. B.; Costa-Cabral, M. C.; Bromirski, P. D.; Miller, N. L.; Coats, R. N.; Loewenstein, M.; Roy, S. B.; MacWilliams, M.

2012-12-01

This work evaluates the implications to flooding risk at the low-lying NASA Ames Research Center in South San Francisco Bay under historical and projected climate and sea level rise. Atmospheric circulation patterns over the Pacific Ocean, influenced by ENSO and PDO, can result in extended periods of higher mean coastal sea level in California. Simultaneously they originate a larger number of storms that make landfall and have higher mean intensity. These storms generate barometrically-induced high water anomalies, and winds that are sometimes capable of producing large coastal waves. Storm surges that propagate from the coast into the estuary and South Bay, and locally-generated waves, may compromise the discharge capacity of stream channels. These conditions also typically generate high intensity rainfall, and the reduced channel capacity may result in fluvial flooding. Such atmospheric circulation patterns may persist for many months, during which California experiences more precipitation events of longer mean duration and higher intensity, leading to large precipitation totals that saturate soils and may exceed the storage capacity of stormwater retention ponds. Future scenarios of sea level rise, that may surpass a meter in this century according to the projections recently published by the National Research Council for states of CA, OR and WA, and projected atmospheric circulation changes associated with anthropogenic climate change, may amplify these risks. We evaluate the impacts of these changes on NASA's Ames Research Center through four areas of study: (i) wetland accretion and evolution as mean sea level rises, with implications to the Bay's response to the sea level rise and storm surges, (ii) hydrodynamic modeling to simulate the propagation of tidal height and storm surges in the Bay and the influence of local winds on wave height, (iii) evaluation of historical data and future climate projections to identify extreme precipitation events, and (iv) regional climate models to identify moisture source areas and evaluate the role of moisture flux on projected California precipitation.;

Building Climate Resilience at NASA Ames Research Center

NASA Astrophysics Data System (ADS)

Iraci, L. T.; Mueller, C.; Podolske, J. R.; Milesi, C.

2016-12-01

NASA Ames Research Center, located at the southern end of the San Francisco Bay (SFB) estuary, has identified three primary vulnerabilities to changes in climate. The Ames Climate Adaptation Science Investigator (CASI) workgroup has studied each of these challenges to operations and the potential exposure of infrastructure and employees to an increased frequency of hazards. Sea level rise inundation scenarios for the SFB Area generally refer to projected scenarios in mean sea level rather than changes in extreme tides that could occur during future storm conditions. In the summer of 2014, high resolution 3-D mapping of the low-lying portion of Ames was performed. Those data are integrated with improved sea level inundation scenarios to identify the buildings, basements and drainage systems potentially affected. We will also identify the impacts of sea level and storm surge effects on transportation to and from the Center. This information will help Center management develop future master plans. Climate change will also lead to changes in temperature, storm frequency and intensity. These changes have potential impacts on localized floods and ecosystems, as well as on electricity and water availability. Over the coming decades, these changes will be imposed on top of ongoing land use and land cover changes, especially those deriving from continued urbanization and increase in impervious surface areas. These coupled changes have the potential to create a series of cascading impacts on ecosystems, including changes in primary productivity and disturbance of hydrological properties and increased flood risk. The majority of the electricity used at Ames is supplied by hydroelectric dams, which will be influenced by reductions in precipitation or changes in the timing or phase of precipitation which reduces snow pack. Coupled with increased demand for summertime air conditioning and other cooling needs, NASA Ames is at risk for electricity shortfalls. To assess the anticipated energy usage as climate changes, the Ames CASI team is collecting historical energy usage data from Ames facilities, historical weather data, and projected future weather parameters from the CASI Climate subgroup. This data will be incorporated into the RETScreen model to predict how energy usage at Ames will change over the coming century.

Bridging groundwater models and decision support with a Bayesian network

USGS Publications Warehouse

Fienen, Michael N.; Masterson, John P.; Plant, Nathaniel G.; Gutierrez, Benjamin T.; Thieler, E. Robert

2013-01-01

Resource managers need to make decisions to plan for future environmental conditions, particularly sea level rise, in the face of substantial uncertainty. Many interacting processes factor in to the decisions they face. Advances in process models and the quantification of uncertainty have made models a valuable tool for this purpose. Long-simulation runtimes and, often, numerical instability make linking process models impractical in many cases. A method for emulating the important connections between model input and forecasts, while propagating uncertainty, has the potential to provide a bridge between complicated numerical process models and the efficiency and stability needed for decision making. We explore this using a Bayesian network (BN) to emulate a groundwater flow model. We expand on previous approaches to validating a BN by calculating forecasting skill using cross validation of a groundwater model of Assateague Island in Virginia and Maryland, USA. This BN emulation was shown to capture the important groundwater-flow characteristics and uncertainty of the groundwater system because of its connection to island morphology and sea level. Forecast power metrics associated with the validation of multiple alternative BN designs guided the selection of an optimal level of BN complexity. Assateague island is an ideal test case for exploring a forecasting tool based on current conditions because the unique hydrogeomorphological variability of the island includes a range of settings indicative of past, current, and future conditions. The resulting BN is a valuable tool for exploring the response of groundwater conditions to sea level rise in decision support.

The changing architecture of sea-level lowstand deposits across the Mid-Pleistocene Transition: South Evoikos Gulf, Greece

NASA Astrophysics Data System (ADS)

Anastasakis, George; Piper, David J. W.

2013-08-01

On subsiding continental shelves, the style of stacked coastal and deltaic progradational packages is directly dependent on relative sea-level changes. In the past ˜0.6 Ma, sea-level change has been dominated by asymmetric 100 ka eustatic sea-level cycles, whereas the record of sea-level changes in earlier Pleistocene progradational sequences is less clear. In a steadily subsiding basin in which accommodation balances sediment flux, the depth of a eustatic lowstand determines the paleo-depth of the deepest clinoform inflection point and the seaward limit of the erosional transgressive surface, whereas the duration of a lowstand controls the amount of progradation that takes place. We report high-resolution seismic profiles of an exceptionally preserved coastal progradational sequence from a coastal embayment in the Aegean Sea that is subsiding at ˜100 m/Ma. The seismic profiles show clinoforms of smaller amplitude and volume that were deposited before the 100 ka cyclic progradational units. This contrasts with literature reports of complexity in progradational sequences at that time. We assume that published stacked benthic foram O-isotope records are a good proxy for the duration and a reasonable proxy for the amplitude of Pleistocene eustatic sea-level cycles. The MIS 6-5 eustatic sea-level rise is recognised based on sedimentation rates from cores. The underlying major progradational units are correlated with the long-duration, extreme lowstand 100 ka cycles of MIS 6, 12 and 16. Changes in the elevation of lowstand inflection points in clinoforms are used to tentatively extend the record back to MIS 38, by comparison with the benthic foram proxy. The deposits of the higher and longer highstands of MIS 25, 31 and 37 are also recognised. This record provides a testable template for future studies of short early Pleistocene sections on land and raises questions of detail about parts of the published δ18O records. It independently supports the recent evidence that the Mid-Pleistocene transition was an abrupt event, with an extreme lowstand in MIS 22.

Effect of fjord geometry on Greenland mass loss in a warming climate (Invited)

NASA Astrophysics Data System (ADS)

Nick, F. M.; Vieli, A.; Andersen, M. L.; Joughin, I. R.

2013-12-01

Over the past decade, ice loss from the Greenland Ice Sheet increased as a result of both increased surface melting and ice discharge through the narrow outlet glaciers. The complicated behaviour of narrow outlet glaciers has not yet been fully captured by the ice-sheet models used to predict Greenland's contribution to future sea level. Here we try to quantify the future dynamic contribution of four major marine terminating outlet glaciers to sea-level rise. We use a glacier flow line model that includes a fully dynamic treatment of marine termini to simulate behavior of Helheim, Kangerdlugssuaq, Petermann and Jakobshavn Isbræ. The contribution from these glaciers to sea-level rise is largely (80%) dynamic in origin and is caused by several episodic retreats past overdeepenings in outlet glacier troughs. Model results show that the shape of the glacier and its fjord can alter how the glacier will respond to a changing climate. Dynamic losses are mainly related to channel geometry and occur when an ice front retreats from a basal high through an overdeepening. Subsequent decelerations in retreat and mass loss mostly coincide with a decrease in water depth as the glacier retreats or re-advances to a new or previous bathymetric high. In some cases, channel narrowing may temporarily slowdown the terminus retreat even when the terminus is located on an upward bed slope.

A Coastal Hazards Data Base for the U.S. East Coast (1992) (NDP-043a)

DOE Data Explorer

Gornitz, Vivien M. [NASA Goddard Inst. for Space Studies (GISS), New York, NY (United States); White, Tammy W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

1992-01-01

This NDP presents data on coastal geology, geomorphology, elevation, erosion, wave heights, tide ranges, and sea levels for the U.S. east coast. These data may be used either by nongeographic database management systems or by raster or vector geographic information systems (GISs). The database integrates several data sets (originally obtained as point, line, and polygon data) for the east coast into 0.25°-latitude by 0.25°-longitude grid cells. Each coastal grid cell contains 28 data variables. This NDP may be used to predict the response of coastal zones on the U.S. east coast to changes in local or global sea levels. Information on the geologic, geomorphic, and erosional states of the coast provides the basic data needed to predict the behavior of the coastal zone into the far future. Thus, these data may be seen as providing a baseline for the calculation of the relative vulnerability of the east coast to projected sea-level rises. This data will also be useful to research, educational, governmental, and private organizations interested in the present and future vulnerability of coastal areas to erosion and inundation. The data are in 13 files, the largest of which is 1.42 MB; the entire data base takes up 3.29 MB, excluding the ARC/INFO^TM files.

The multi-millennial Antarctic commitment to future sea-level rise

NASA Astrophysics Data System (ADS)

Golledge, Nicholas R.; Kowalewski, Douglas E.; Naish, Timothy R.; Levy, Richard H.; Fogwill, Christopher J.; Gasson, Edward G. W.

2016-04-01

Atmospheric warming is projected to increase global mean surface temperatures by 0.3 to 4.8 degrees Celsius above present values by the end of this century (Collins et al., 2013). If anthropogenic emissions continue unchecked, the warming increase may reach 8-10 degrees Celsius by 2300 (Rogelj et al., 2012). The contribution that large ice sheets will make to sea-level rise under such warming scenarios is difficult to quantify because the equilibrium-response timescale of ice sheets is longer than those of the atmosphere or ocean. Here we use a coupled ice-sheet/ice-shelf model to show that if atmospheric warming exceeds 1.5 to 2 degrees Celsius above present, collapse of the major Antarctic ice shelves triggers a centennial- to millennial-scale response of the Antarctic ice sheet in which enhanced viscous flow produces a long-term commitment (an unstoppable contribution) to sea-level rise. Our simulations represent the response of the present-day Antarctic ice-sheet system to the oceanic and climatic changes of four representative concentration pathways (RCPs) from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (Collins et al., 2013). We find that substantial Antarctic ice loss can be prevented only by limiting greenhouse gas emissions to RCP 2.6 levels. Higher-emissions scenarios lead to ice loss from Antarctic that will raise sea level by 0.6-3 metres by the year 2300. Our results imply that greenhouse gas emissions in the next few decades will strongly influence the long-term contribution of the Antarctic ice sheet to global sea level.

Amount and distribution of neustonic micro-plastic off the western Sardinian coast (Central-Western Mediterranean Sea).

PubMed

de Lucia, Giuseppe Andrea; Caliani, Ilaria; Marra, Stefano; Camedda, Andrea; Coppa, Stefania; Alcaro, Luigi; Campani, Tommaso; Giannetti, Matteo; Coppola, Daniele; Cicero, Anna Maria; Panti, Cristina; Baini, Matteo; Guerranti, Cristiana; Marsili, Letizia; Massaro, Giorgio; Fossi, Maria Cristina; Matiddi, Marco

2014-09-01

A plethora of different sampling methodologies has been used to document the presence of micro-plastic fragments in sea water. European Marine Strategy suggests to improve standard techniques to make future data comparable. We use Manta Trawl sampling technique to quantify abundance and distribution of micro-plastic fragments in Sardinian Sea (Western Mediterranean), and their relation with phthalates and organoclorine in the neustonic habitat. Our results highlight a quite high average plastic abundance value (0.15 items/m(3)), comparable to the levels detected in other areas of the Mediterranean. "Site" is the only factor that significantly explains the differences observed in micro-plastic densities. Contaminant levels show high spatial and temporal variation. In every station, HCB is the contaminant with the lowest concentration while PCBs shows the highest levels. This work, in line with Marine Strategy directives, represents a preliminary study for the analysis of plastic impact on marine environment of Sardinia. Copyright © 2014 Elsevier Ltd. All rights reserved.

Half-metre sea-level fluctuations on centennial timescales from mid-Holocene corals of Southeast Asia

PubMed Central

Meltzner, Aron J.; Switzer, Adam D.; Horton, Benjamin P.; Ashe, Erica; Qiu, Qiang; Hill, David F.; Bradley, Sarah L.; Kopp, Robert E.; Hill, Emma M.; Majewski, Jędrzej M.; Natawidjaja, Danny H.; Suwargadi, Bambang W.

2017-01-01

Sea-level rise is a global problem, yet to forecast future changes, we must understand how and why relative sea level (RSL) varied in the past, on local to global scales. In East and Southeast Asia, details of Holocene RSL are poorly understood. Here we present two independent high-resolution RSL proxy records from Belitung Island on the Sunda Shelf. These records capture spatial variations in glacial isostatic adjustment and paleotidal range, yet both reveal a RSL history between 6850 and 6500 cal years BP that includes two 0.6 m fluctuations, with rates of RSL change reaching 13±4 mm per year (2σ). Observations along the south coast of China, although of a lower resolution, reveal fluctuations similar in amplitude and timing to those on the Sunda Shelf. The consistency of the Southeast Asian records, from sites 2,600 km apart, suggests that the records reflect regional changes in RSL that are unprecedented in modern times. PMID:28186122

Global climate change and local land subsidence exacerbate inundation risk to the San Francisco Bay Area

PubMed Central

Shirzaei, Manoochehr; Bürgmann, Roland

2018-01-01

The current global projections of future sea level rise are the basis for developing inundation hazard maps. However, contributions from spatially variable coastal subsidence have generally not been considered in these projections. We use synthetic aperture radar interferometric measurements and global navigation satellite system data to show subsidence rates of less than 2 mm/year along most of the coastal areas along San Francisco Bay. However, rates exceed 10 mm/year in some areas underlain by compacting artificial landfill and Holocene mud deposits. The maps estimating 100-year inundation hazards solely based on the projection of sea level rise from various emission scenarios underestimate the area at risk of flooding by 3.7 to 90.9%, compared with revised maps that account for the contribution of local land subsidence. Given ongoing land subsidence, we project that an area of 125 to 429 km2 will be vulnerable to inundation, as opposed to 51 to 413 km2 considering sea level rise alone. PMID:29536042

The Geology of the Florida Keys.

ERIC Educational Resources Information Center

Shinn, Eugene A.

1988-01-01

Describes some of the ancient geologic history of the Florida Keys from Key Largo to Key West including the effects of glaciers, sea level rise, reef distribution, spurs and grooves, backstepping and ecological zonation, growth rates and erosion. Predicts future changes in this area. (CW)

Extreme sea levels on the rise along Europe's coasts

NASA Astrophysics Data System (ADS)

Vousdoukas, Michalis I.; Mentaschi, Lorenzo; Voukouvalas, Evangelos; Verlaan, Martin; Feyen, Luc

2017-03-01

Future extreme sea levels (ESLs) and flood risk along European coasts will be strongly impacted by global warming. Yet, comprehensive projections of ESL that include mean sea level (MSL), tides, waves, and storm surges do not exist. Here, we show changes in all components of ESLs until 2100 in view of climate change. We find that by the end of this century, the 100-year ESL along Europe's coastlines is on average projected to increase by 57 cm for Representative Concentration Pathways (RCP)4.5 and 81 cm for RCP8.5. The North Sea region is projected to face the highest increase in ESLs, amounting to nearly 1 m under RCP8.5 by 2100, followed by the Baltic Sea and Atlantic coasts of the UK and Ireland. Relative sea level rise (RSLR) is shown to be the main driver of the projected rise in ESL, with increasing dominance toward the end of the century and for the high-concentration pathway. Changes in storm surges and waves enhance the effects of RSLR along the majority of northern European coasts, locally with contributions up to 40%. In southern Europe, episodic extreme events tend to stay stable, except along the Portuguese coast and the Gulf of Cadiz where reductions in surge and wave extremes offset RSLR by 20-30%. By the end of this century, 5 million Europeans currently under threat of a 100-year ESL could be annually at risk from coastal flooding under high-end warming. The presented dataset is available through this link: http://data.jrc.ec.europa.eu/collection/LISCOAST.

Use of CMIP Atmospheric Boundary Conditions with ISMs

NASA Technical Reports Server (NTRS)

Cullather, Richard; Nowicki, Sophie

2017-01-01

Dynamical ice sheet models are being used in simulations of future sea level change resulting from changing glacier mass. One of the difficulties in doing so are the input conditions obtained from earth system models. These inputs can be of coarse spatial resolution, and may not represent surface melt in a future climate. I review various methods for overcoming this with the aim of promoting discussion among modelers.

Sea-level rise: towards understanding local vulnerability

NASA Astrophysics Data System (ADS)

Rahmstorf, Stefan

2012-06-01

Projections of global sea-level rise into the future have become more pessimistic over the past five years or so. A global rise by more than one metre by the year 2100 is now widely accepted as a serious possibility if greenhouse gas emissions continue unabated. That is witnessed by the scientific assessments that were made since the last IPCC report was published in 2007. The Delta Commission of the Dutch government projected up to 1.10 m as a 'high-end' scenario (Vellinga et al 2009). The Scientific Committee on Antarctic Research (SCAR) projected up to 1.40 m (Scientific Committee on Antarctic Research 2009), and the Arctic Monitoring and Assessment Programme (AMAP) gives a range of 0.90-1.60 m in its 2011 report (Arctic Monitoring and Assessment Programme 2011). And recently the US Army Corps of Engineers recommends using a 'low', an 'intermediate' and a 'high' scenario for global sea-level rise when planning civil works programmes, with the high one corresponding to a 1.50 m rise by 2100 (US Army Corps of Engineers 2011). This more pessimistic view is based on a number of observations, most importantly perhaps the fact that sea level has been rising at least 50% faster in the past decades than projected by the IPCC (Rahmstorf et al 2007, IPCC 2007). Also, the rate of rise (averaged over two decades) has accelerated threefold, from around 1 mm yr-1 at the start of the 20th century to around 3 mm yr-1 over the past 20 years (Church and White 2006), and this rate increase closely correlates with global warming (Rahmstorf et al 2011). The IPCC projections, which assume almost no further acceleration in the 20th century, thus look less plausible. And finally the observed net mass loss of the two big continental ice sheets (Van den Broeke et al 2011) calls into question the assumption that ice accumulation in Antarctica would largely balance ice loss from Greenland in the course of further global warming (IPCC 2007). With such a serious sea-level rise on the horizon, experts are increasingly looking at its potential impacts on coasts to facilitate local adaptation planning. This is a more complex issue than one might think, because different stretches of coast can be affected in very different ways. First of all, the sea-level response to global warming will not be globally uniform, since factors like changes in ocean currents (Levermann et al 2005) and the changing gravitational pull of continental ice (Mitrovica et al 2001) affect the local rise. Secondly, superimposed on the climatic trend is natural variability in sea level, which regionally can be as large as the climatic signal on multi-decadal timescales. Over the past decades, sea level has dropped in sizable parts of the world ocean, although it has of course risen in global mean (IPCC 2007). Thirdly, local land uplift or subsidence affects the local sea-level change relative to the coast, both for natural reasons (post-glacial isostatic adjustment centred on regions that were covered by ice sheets during the last ice age) and artificial ones (e.g., extraction of water or oil as in the Gulf of Mexico). Finally, local vulnerability to sea-level rise depends on many factors. Two interesting new studies in this journal (Tebaldi et al 2012, Strauss et al 2012) make important steps towards understanding sea-level vulnerability along the coasts of the United States, with methods that could also be applied elsewhere. The first, by Strauss and colleagues, merges high-resolution topographic data and a newly available tidal model together with population and housing data in order to estimate what land area and population would be at risk given certain increments in sea level. The results are mapped and tabulated at county and city level. They reveal the 'hot spots' along the US coast where sea-level rise is of the highest concern because of large populations living near the high-tide line: New York City and Long Island; the New Jersey shore; the Norfolk, Virginia, area; near Charleston, South Carolina; coastal cities across Florida, especially its southeast and the Tampa area; New Orleans; the San Francisco Bay Area and San Joaquin Delta; and greater Los Angeles. Overall, 3.7 million people across the US are estimated to live within 1 m of the present high-tide line. The second paper, by Tebaldi et al, specifically looks at storm surges and how their frequency is expected to change along the US coastline in the coming four decades due to rising sea levels. They first estimate future local sea-level rise relative to the land by combining the observed local trend of the past fifty years with a future acceleration due to global warming as estimated by a semi-empirical model (Vermeer and Rahmstorf 2009). Then they use past storm surge statistics for many different locations and shift the return level curves according to the projected sea-level rise. The authors find that by mid-century, in some locations what is now a once-per-century flooding event could become an annual event. Those are exceptional places—but at about a third of the sites investigated, a century flood could become a once-per-decade flood. Of course, many of these events need not have dramatic impacts: in fact, locations where rare floods are quite small in amplitude (and hence presumably modest in their impacts) are precisely those where the return period decreases most dramatically. In a place where the once-per-century flood is only 50 cm higher than the annual flood, a typical 30 cm rise in sea level makes a bigger difference than one in a place where the century flood is 2 m higher than the annual flood. Nevertheless, the expected large changes in return periods and return levels of storm surges clearly demonstrate that accounting for accelerating sea-level rise is vital in the planning and design of coastal infrastructure. But most importantly, these studies highlight the fact that the modern world, with many millions of people living right by the coast, is highly vulnerable to even modest sea-level rise. Losing just 1% of the present continental ice would raise sea level globally by about 75 cm—a tiny amount in the perspective of palaeoclimate history, e.g. the 120 m rise at the end of the last ice age, but a large amount in terms of impacts on human society. We should do everything we can to limit global warming and thereby sea-level rise to a manageable level. References Arctic Monitoring and Assessment Programme 2011 Snow, Water, Ice and Permafrost in the Arctic (Oslo: AMAP) Church J A and White N J 2006 A 20th century acceleration in global sea-level rise Geophys. Res. Lett. 33 L01602 IPCC 2007 Climate Change 2007: The Physical Science Basis. The Fourth Assessment Report of the Intergovernmental Panel on Climate Change ed S Solomon et al (Cambridge: Cambridge University Press) Levermann A, Griesel A, Hofmann M, Montoya M and Rahmstorf S 2005 Dynamic sea level changes following changes in the thermohaline circulation Clim. Dyn. 24 347-54 Mitrovica J X, Tamisiea M E, Davis J L and Milne G A 2001 Recent mass balance of polar ice sheets inferred from patterns of global sea-level change Nature 409 1026-9 Rahmstorf S, Cazenave A, Church J A, Hansen J E, Keeling R F, Parker D E and Somerville C J 2007 Recent climate observations compared to projections Science 316 709 Rahmstorf S, Perrette M and Vermeer M 2011 Testing the robustness of semi-empirical sea level projections Clim. Dyn. at press (doi:10.1007/s00382-011-1226-7) Scientific Committee on Antarctic Research 2009 Antarctic Climate Change and the Environment (Cambridge: Scott Polar Research Institute) Strauss B, Ziemlinski R, Weiss J and Overpeck J T 2012 Tidally-adjusted estimates of topographic vulnerability to sea level rise and flooding for the contiguous United States Environ. Res. Lett. 7 014033 Tebaldi C, Strauss B and Zervas C 2012 Modelling sea level rise impacts on storm surges along US coasts Environ. Res. Lett. 7 014032 US Army Corps of Engineers 2011 Sea-Level Change Considerations for Civil Works Programs (Washington, DC: Department of the Army) Van den Broeke M R, Bamber J, Lenaerts J and Rignot E 2011 Ice sheets and sea level: thinking outside the box Sur. Geophys. 32 495-505 Vellinga P, Katsman C A, Sterl A and Beersma J J 2009 Exploring high-end climate change scenarios for flood protection of the Netherlands International Scientific Assessment Carried out at the Request of the Delta Committee (De Bilt: KNMI) Vermeer M and Rahmstorf S 2009 Global sea level linked to global temperature Proc. Natl Acad. Sci. USA 106 21527-32

Using Groundwater Modeling to Evaluate Impacts of Sea Level Rise on A Coastal Riverine Ecosystem: A Case Study of Saint Jones River Water Shed

NASA Astrophysics Data System (ADS)

He, C.; McKenna, T. E.

2016-12-01

A 3-D, transient, variable-density groundwater flow model (SEAWAT) is used to simulate the groundwater response to predicted sea level rise in the Saint Jones River watershed adjacent to the Delaware Estuary. Sea level rise directly leads to substantial changes in the depth of water table, and these changes can extend far inland due to the long tidal rivers in this area. This research studied the impacts of three different sea level rise scenarios (0.5m, 1.0m and 1.5m) on two concerned aspects in the area: failure of septic tank system and loss of agriculture land. The model results indicate that 1) 10% 13% of current existing septic tank will fail as the water table rise to less than 1.5meters from land surface, and 2) approximate 271 to 927 acres of agriculture land, which covers about 4% 13% of total current agriculture land in the study area, will be lost due to water table rise above the effective rooting depth. To count in the uncertainty of climate change in the future, Monte Carlo simulation was applied and a linear transformation model was created and verified to facilitate the tremendous computation.

The Arctic-Subarctic Sea Ice System is Entering a Seasonal Regime: Implications for Future Arctic Amplication

NASA Astrophysics Data System (ADS)

Haine, T. W. N.; Martin, T.

2017-12-01

The loss of Arctic sea ice is a conspicuous example of climate change. Climate models project ice-free conditions during summer this century under realistic emission scenarios, reflecting the increase in seasonality in ice cover. To quantify the increased seasonality in the Arctic-Subarctic sea ice system, we define a non-dimensional seasonality number for sea ice extent, area, and volume from satellite data and realistic coupled climate models. We show that the Arctic-Subarctic, i.e. the northern hemisphere, sea ice now exhibits similar levels of seasonality to the Antarctic, which is in a seasonal regime without significant change since satellite observations began in 1979. Realistic climate models suggest that this transition to the seasonal regime is being accompanied by a maximum in Arctic amplification, which is the faster warming of Arctic latitudes compared to the global mean, in the 2010s. The strong link points to a peak in sea-ice-related feedbacks that occurs long before the Arctic becomes ice-free in summer.

Increased future ice discharge from Antarctica owing to higher snowfall.

PubMed

Winkelmann, R; Levermann, A; Martin, M A; Frieler, K

2012-12-13

Anthropogenic climate change is likely to cause continuing global sea level rise, but some processes within the Earth system may mitigate the magnitude of the projected effect. Regional and global climate models simulate enhanced snowfall over Antarctica, which would provide a direct offset of the future contribution to global sea level rise from cryospheric mass loss and ocean expansion. Uncertainties exist in modelled snowfall, but even larger uncertainties exist in the potential changes of dynamic ice discharge from Antarctica and thus in the ultimate fate of the precipitation-deposited ice mass. Here we show that snowfall and discharge are not independent, but that future ice discharge will increase by up to three times as a result of additional snowfall under global warming. Our results, based on an ice-sheet model forced by climate simulations through to the end of 2500 (ref. 8), show that the enhanced discharge effect exceeds the effect of surface warming as well as that of basal ice-shelf melting, and is due to the difference in surface elevation change caused by snowfall on grounded versus floating ice. Although different underlying forcings drive ice loss from basal melting versus increased snowfall, similar ice dynamical processes are nonetheless at work in both; therefore results are relatively independent of the specific representation of the transition zone. In an ensemble of simulations designed to capture ice-physics uncertainty, the additional dynamic ice loss along the coastline compensates between 30 and 65 per cent of the ice gain due to enhanced snowfall over the entire continent. This results in a dynamic ice loss of up to 1.25 metres in the year 2500 for the strongest warming scenario. The reported effect thus strongly counters a potential negative contribution to global sea level by the Antarctic Ice Sheet.

Using palaeoclimate data to improve models of the Antarctic Ice Sheet

NASA Astrophysics Data System (ADS)

Phipps, Steven; King, Matt; Roberts, Jason; White, Duanne

2017-04-01

Ice sheet models are the most descriptive tools available to simulate the future evolution of the Antarctic Ice Sheet (AIS), including its contribution towards changes in global sea level. However, our knowledge of the dynamics of the coupled ice-ocean-lithosphere system is inevitably limited, in part due to a lack of observations. Furthemore, to build computationally efficient models that can be run for multiple millennia, it is necessary to use simplified descriptions of ice dynamics. Ice sheet modelling is therefore an inherently uncertain exercise. The past evolution of the AIS provides an opportunity to constrain the description of physical processes within ice sheet models and, therefore, to constrain our understanding of the role of the AIS in driving changes in global sea level. We use the Parallel Ice Sheet Model (PISM) to demonstrate how palaeoclimate data can improve our ability to predict the future evolution of the AIS. A 50-member perturbed-physics ensemble is generated, spanning uncertainty in the parameterisations of three key physical processes within the model: (i) the stress balance within the ice sheet, (ii) basal sliding and (iii) calving of ice shelves. A Latin hypercube approach is used to optimally sample the range of uncertainty in parameter values. This perturbed-physics ensemble is used to simulate the evolution of the AIS from the Last Glacial Maximum ( 21,000 years ago) to present. Palaeoclimate records are then used to determine which ensemble members are the most realistic. This allows us to use data on past climates to directly constrain our understanding of the past contribution of the AIS towards changes in global sea level. Critically, it also allows us to determine which ensemble members are likely to generate the most realistic projections of the future evolution of the AIS.

Using paleoclimate data to improve models of the Antarctic Ice Sheet

NASA Astrophysics Data System (ADS)

King, M. A.; Phipps, S. J.; Roberts, J. L.; White, D.

2016-12-01

Ice sheet models are the most descriptive tools available to simulate the future evolution of the Antarctic Ice Sheet (AIS), including its contribution towards changes in global sea level. However, our knowledge of the dynamics of the coupled ice-ocean-lithosphere system is inevitably limited, in part due to a lack of observations. Furthemore, to build computationally efficient models that can be run for multiple millennia, it is necessary to use simplified descriptions of ice dynamics. Ice sheet modeling is therefore an inherently uncertain exercise. The past evolution of the AIS provides an opportunity to constrain the description of physical processes within ice sheet models and, therefore, to constrain our understanding of the role of the AIS in driving changes in global sea level. We use the Parallel Ice Sheet Model (PISM) to demonstrate how paleoclimate data can improve our ability to predict the future evolution of the AIS. A large, perturbed-physics ensemble is generated, spanning uncertainty in the parameterizations of four key physical processes within ice sheet models: ice rheology, ice shelf calving, and the stress balances within ice sheets and ice shelves. A Latin hypercube approach is used to optimally sample the range of uncertainty in parameter values. This perturbed-physics ensemble is used to simulate the evolution of the AIS from the Last Glacial Maximum ( 21,000 years ago) to present. Paleoclimate records are then used to determine which ensemble members are the most realistic. This allows us to use data on past climates to directly constrain our understanding of the past contribution of the AIS towards changes in global sea level. Critically, it also allows us to determine which ensemble members are likely to generate the most realistic projections of the future evolution of the AIS.

Salt dissolution and sinkhole formation: Results of laboratory experiments

NASA Astrophysics Data System (ADS)

Oz, Imri; Eyal, Shalev; Yoseph, Yechieli; Ittai, Gavrieli; Elad, Levanon; Haim, Gvirtzman

2016-10-01

The accepted mechanism for the formation of thousands of sinkholes along the coast of the Dead Sea suggests that their primary cause is dissolution of a salt layer by groundwater undersaturated with respect to halite. This is related to the drop in the Dead Sea level, which caused a corresponding drop of the freshwater-saltwater interface, resulting in fresher groundwater replacing the brines that were in contact with the salt layer. In this study we used physical laboratory experiments to examine the validity of this mechanism by reproducing the full dynamic natural process and to examine the impact of different hydrogeological characteristics on this process. The experimental results show surface subsidence and sinkhole formation. The stratigraphic configurations of the aquifer, together with the mechanical properties of the salt layer, determine the dynamic patterns of the sinkhole formation (instantaneous versus gradual formation). Laboratory experiments were also used to study the potential impact of future stratification in the Dead Sea, if and when the "Red Sea-Dead Sea Canal" project is carried out, and the Dead Sea level remains stable. The results show that the dissolution rates are slower by 1 order of magnitude in comparison with a nonstratified saltwater body, and therefore, the processes of salt dissolution and sinkhole formation will be relatively restrained under these conditions.

Measurement of historical cliff-top changes and estimation of future trends using GIS data between Bridlington and Hornsea - Holderness Coast (UK)

NASA Astrophysics Data System (ADS)

Castedo, Ricardo; de la Vega-Panizo, Rogelio; Fernández-Hernández, Marta; Paredes, Carlos

2015-02-01

A key requirement for effective coastal zone management is good knowledge of historical rates of change and the ability to predict future shoreline evolution, especially for rapidly eroding areas. Historical shoreline recession analysis was used for the prediction of future cliff shoreline positions along a section of 9 km between Bridlington and Hornsea, on the northern area of the Holderness Coast, UK. The analysis was based on historical maps and aerial photographs dating from 1852 to 2011 using the Digital Shoreline Analysis System (DSAS) 4.3, extension of ESRI's ArcInfo 10.×. The prediction of future shorelines was performed for the next 40 years using a variety of techniques, ranging from extrapolation from historical data, geometric approaches like the historical trend analysis, to a process-response numerical model that incorporates physically-based equations and geotechnical stability analysis. With climate change and sea-level rise implying that historical rates of change may not be a reliable guide for the future, enhanced visualization of the evolving coastline has the potential to improve awareness of these changing conditions. Following the IPCC, 2013 report, two sea-level rise rates, 2 mm/yr and 6 mm/yr, have been used to estimate future shoreline conditions. This study illustrated that good predictive models, once their limitations are estimated or at least defined, are available for use by managers, planners, engineers, scientists and the public to make better decisions regarding coastal management, development, and erosion-control strategies.

Disentangling the impact of nutrient load and climate changes on Baltic Sea hypoxia and eutrophication since 1850

NASA Astrophysics Data System (ADS)

Meier, H. E. M.; Eilola, K.; Almroth-Rosell, E.; Schimanke, S.; Kniebusch, M.; Höglund, A.; Pemberton, P.; Liu, Y.; Väli, G.; Saraiva, S.

2018-06-01

In the Baltic Sea hypoxia has been increased considerably since the first oxygen measurements became available in 1898. In 2016 the annual maximum extent of hypoxia covered an area of the sea bottom of about 70,000 km2, comparable with the size of Ireland, whereas 150 years ago hypoxia was presumably not existent or at least very small. The general view is that the increase in hypoxia was caused by eutrophication due to anthropogenic riverborne nutrient loads. However, the role of changing climate, e.g. warming, is less clear. In this study, different causes of expanding hypoxia were investigated. A reconstruction of the changing Baltic Sea ecosystem during the period 1850-2008 was performed using a coupled physical-biogeochemical ocean circulation model. To disentangle the drivers of eutrophication and hypoxia a series of sensitivity experiments was carried out. We found that the decadal to centennial changes in eutrophication and hypoxia were mainly caused by changing riverborne nutrient loads and atmospheric deposition. The impacts of other drivers like observed warming and eustatic sea level rise were comparatively smaller but still important depending on the selected ecosystem indicator. Further, (1) fictively combined changes in air temperature, cloudiness and mixed layer depth chosen from 1904, (2) exaggerated increases in nutrient concentrations in the North Sea and (3) high-end scenarios of future sea level rise may have an important impact. However, during the past 150 years hypoxia would not have been developed if nutrient conditions had remained at pristine levels.

Statistical modelling of sea lice count data from salmon farms in the Faroe Islands.

PubMed

Gislason, H

2018-06-01

Fiskaaling regularly counts the number of sea lice in the attached development stages (chalimus, mobiles and adult) for the salmon farms in the Faroe Islands. A statistical model of the data is developed. In the model, the sea-lice infection is represented by the chalimus (or mobile) lice developing into adult lice and is used to simulate past and current levels of adult lice-including treatments-as well as to predict the adult sea lice level 1-2 months into the future. Time series of the chalimus and adult lice show cross-correlations that shift in time and grow in size with temperature. This implies in situ the temperature-dependent development times of about 56 down to 42 days and the inverted development times (growth rates) of 0.018 up to 0.024 lice/day at 8-10°C. The temperature dependence DT=α1T+α2α3=17,840T+7.439-2.128is approximated byD1T=105.2-6.578T≈49 days at the mean temperature 8.5°C-similar to DchaT=100.6-6.507T≈45 days from EWOS data. The observed development times at four sites for a year (2010-11) were 49, 50, 51 and 52 days, respectively. Finally, we estimate the sea lice production from fish farms to discuss approaches to control the sea lice epidemics-preferably by natural means. This study is useful for understanding sea lice levels and treatments, and for in situ analysis of the sea-lice development times and growth rates. © 2017 John Wiley & Sons Ltd.

Uncertainties in forecasting the response of polar bears to global climate change

USGS Publications Warehouse

Douglas, David C.; Atwood, Todd C.; Butterworth, Andy

2017-01-01

Several sources of uncertainty affect how precisely the future status of polar bears (Ursus maritimus) can be forecasted. Foremost are unknowns about the future levels of global greenhouse gas emissions, which could range from an unabated increase to an aggressively mitigated reduction. Uncertainties also arise because different climate models project different amounts and rates of future warming (and sea ice loss)—even for the same emission scenario. There are also uncertainties about how global warming could affect the Arctic Ocean’s food web, so even if climate models project the presence of sea ice in the future, the availability of polar bear prey is not guaranteed. Under a worst-case emission scenario in which rates of greenhouse gas emissions continue to rise unabated to century’s end, the uncertainties about polar bear status center on a potential for extinction. If the species were to persist, it would likely be restricted to a high-latitude refugium in northern Canada and Greenland—assuming a food web also existed with enough accessible prey to fuel weight gains for surviving onshore during the most extreme years of summer ice melt. On the other hand, if emissions were to be aggressively mitigated at the levels proposed in the Paris Climate Agreement, healthy polar bear populations would probably continue to occupy all but the most southern areas of their contemporary summer range. While polar bears have survived previous warming phases—which indicate some resiliency to the loss of sea ice habitat—what is certain is that the present pace of warming is unprecedented and will increasingly expose polar bears to historically novel stressors.

Modelling West Antarctic ice sheet growth and collapse through the past five million years.

PubMed

Pollard, David; DeConto, Robert M

2009-03-19

The West Antarctic ice sheet (WAIS), with ice volume equivalent to approximately 5 m of sea level, has long been considered capable of past and future catastrophic collapse. Today, the ice sheet is fringed by vulnerable floating ice shelves that buttress the fast flow of inland ice streams. Grounding lines are several hundred metres below sea level and the bed deepens upstream, raising the prospect of runaway retreat. Projections of future WAIS behaviour have been hampered by limited understanding of past variations and their underlying forcing mechanisms. Its variation since the Last Glacial Maximum is best known, with grounding lines advancing to the continental-shelf edges around approximately 15 kyr ago before retreating to near-modern locations by approximately 3 kyr ago. Prior collapses during the warmth of the early Pliocene epoch and some Pleistocene interglacials have been suggested indirectly from records of sea level and deep-sea-core isotopes, and by the discovery of open-ocean diatoms in subglacial sediments. Until now, however, little direct evidence of such behaviour has been available. Here we use a combined ice sheet/ice shelf model capable of high-resolution nesting with a new treatment of grounding-line dynamics and ice-shelf buttressing to simulate Antarctic ice sheet variations over the past five million years. Modelled WAIS variations range from full glacial extents with grounding lines near the continental shelf break, intermediate states similar to modern, and brief but dramatic retreats, leaving only small, isolated ice caps on West Antarctic islands. Transitions between glacial, intermediate and collapsed states are relatively rapid, taking one to several thousand years. Our simulation is in good agreement with a new sediment record (ANDRILL AND-1B) recovered from the western Ross Sea, indicating a long-term trend from more frequently collapsed to more glaciated states, dominant 40-kyr cyclicity in the Pliocene, and major retreats at marine isotope stage 31 ( approximately 1.07 Myr ago) and other super-interglacials.

Comprehensive analysis of differentially expressed genes reveals the molecular response to elevated CO2 levels in two sea buckthorn cultivars.

PubMed

Zhang, Guoyun; Zhang, Tong; Liu, Juanjuan; Zhang, Jianguo; He, Caiyun

2018-06-20

Atmospheric carbon dioxide (CO 2 ) concentration increases every year. It is critical to understand the elevated CO 2 response molecular mechanisms of plants using genomic techniques. Hippophae rhamnoides L. is a high stress resistance plant species widely distributed in Europe and Asia. However, the molecular mechanism of elevated CO 2 response in H. rhamnoides has been limited. In this study, transcriptomic analysis of two sea buckthorn cultivars under different CO 2 concentrations was performed, based on the next-generation illumina sequencing platform and de novo assembly. We identified 4740 differentially expressed genes in sea buckthorn response to elevated CO 2 concentrations. According to the gene ontology (GO) results, photosystem I, photosynthesis and chloroplast thylakoid membrane were the main enriched terms in 'xiangyang' sea buckthorn. In 'zhongguo' sea buckthorn, photosynthesis was also the main significantly enriched term. However, the number of photosynthesis related differentially expressed genes were different between two sea buckthorn cultivars. Our GO and pathway analyses indicated that the expression levels of the transcription factors WRKY, MYB and NAC were significantly different between the two sea buckthorn cultivars. This study provides a reliable transcriptome sequence resource and is a valuable resource for genetic and genomic researches for plants under high CO 2 concentration in the future. Copyright © 2018 Elsevier B.V. All rights reserved.

Changes in size and trends of North American sea duck populations associated with North Pacific oceanic regime shifts

USGS Publications Warehouse

Flint, Paul L.

2013-01-01

Broad-scale multi-species declines in populations of North American sea ducks for unknown reasons is cause for management concern. Oceanic regime shifts have been associated with rapid changes in ecosystem structure of the North Pacific and Bering Sea. However, relatively little is known about potential effects of these changes in oceanic conditions on marine bird populations at broad scales. I examined changes in North American breeding populations of sea ducks from 1957 to 2011 in relation to potential oceanic regime shifts in the North Pacific in 1977, 1989, and 1998. There was strong support for population-level effects of regime shifts in 1977 and 1989, but little support for an effect of the 1998 shift. The continental-level effects of these regime shifts differed across species groups and time. Based on patterns of sea duck population dynamics associated with regime shifts, it is unclear if the mechanism of change relates to survival or reproduction. Results of this analysis support the hypothesis that population size and trends of North American sea ducks are strongly influenced by oceanic conditions. The perceived population declines appear to have halted >20 years ago, and populations have been relatively stable or increasing since that time. Given these results, we should reasonably expect dramatic changes in sea duck population status and trends with future oceanic regime shifts.

78 FR 54638 - Request for Information To Inform the Title III Technical Assistance Agenda and the Future...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-05

... assistance needed and at what level (e.g., SEA, LEA, school or classroom)? a. Common Core State Standards or..., or students; k. ESEA flexibility and ELs; l. Science, technology, engineering, and math (STEM...; o. ELs at the secondary school level; p. ELs served under IDEA; q. Civil rights and ELs; or r. Other...

Combined effects of projected sea level rise, storm surge, and peak river flows on water levels in the Skagit Floodplain

USGS Publications Warehouse

Hamman, Josheph J; Hamlet, Alan F.; Fuller, Roger; Grossman, Eric E.

2016-01-01

Current understanding of the combined effects of sea level rise (SLR), storm surge, and changes in river flooding on near-coastal environments is very limited. This project uses a suite of numerical models to examine the combined effects of projected future climate change on flooding in the Skagit floodplain and estuary. Statistically and dynamically downscaled global climate model scenarios from the ECHAM-5 GCM were used as the climate forcings. Unregulated daily river flows were simulated using the VIC hydrology model, and regulated river flows were simulated using the SkagitSim reservoir operations model. Daily tidal anomalies (TA) were calculated using a regression approach based on ENSO and atmospheric pressure forcing simulated by the WRF regional climate model. A 2-D hydrodynamic model was used to estimate water surface elevations in the Skagit floodplain using resampled hourly hydrographs keyed to regulated daily flood flows produced by the reservoir simulation model, and tide predictions adjusted for SLR and TA. Combining peak annual TA with projected sea level rise, the historical (1970–1999) 100-yr peak high water level is exceeded essentially every year by the 2050s. The combination of projected sea level rise and larger floods by the 2080s yields both increased flood inundation area (+ 74%), and increased average water depth (+ 25 cm) in the Skagit floodplain during a 100-year flood. Adding sea level rise to the historical FEMA 100-year flood resulted in a 35% increase in inundation area by the 2040's, compared to a 57% increase when both SLR and projected changes in river flow were combined.

Physical and Economic Impacts of Sea-Level Rise and Low Probability Flooding Events on Coastal Communities

PubMed Central

Prime, Thomas; Brown, Jennifer M.; Plater, Andrew J.

2015-01-01

Conventionally flood mapping typically includes only a static water level (e.g. peak of a storm tide) in coastal flood inundation events. Additional factors become increasingly important when increased water-level thresholds are met during the combination of a storm tide and increased mean sea level. This research incorporates factors such as wave overtopping and river flow in a range of flood inundation scenarios of future sea-level projections for a UK case study of Fleetwood, northwest England. With increasing mean sea level it is shown that wave overtopping and river forcing have an important bearing on the cost of coastal flood events. The method presented converts inundation maps into monetary cost. This research demonstrates that under scenarios of joint extreme surge-wave-river events the cost of flooding can be increased by up to a factor of 8 compared with an increase in extent of up to a factor of 3 relative to “surge alone” event. This is due to different areas being exposed to different flood hazards and areas with common hazard where flood waters combine non-linearly. This shows that relying simply on flood extent and volume can under-predict the actual economic impact felt by a coastal community. Additionally, the scenario inundation depths have been presented as “brick course” maps, which represent a new way of interpreting flood maps. This is primarily aimed at stakeholders to increase levels of engagement within the coastal community. PMID:25710497

Atoll groundwater movement and its response to climatic and sea-level fluctuations

USGS Publications Warehouse

Oberle, Ferdinand; Swarzenski, Peter W.; Storlazzi, Curt

2017-01-01

Groundwater resources of low-lying atoll islands are threatened due to short-term and long-term changes in rainfall, wave climate, and sea level. A better understanding of how these forcings affect the limited groundwater resources was explored on Roi-Namur in the Republic of the Marshall Islands. As part of a 16-month study, a rarely recorded island-overwash event occurred and the island’s aquifer’s response was measured. The findings suggest that small-scale overwash events cause an increase in salinity of the freshwater lens that returns to pre-overwash conditions within one month. The overwash event is addressed in the context of climate-related local sea-level change, which suggests that overwash events and associated degradations in freshwater resources are likely to increase in severity in the future due to projected rises in sea level. Other forcings, such as severe rainfall events, were shown to have caused a sudden freshening of the aquifer, with salinity levels retuning to pre-rainfall levels within three months. Tidal forcing of the freshwater lens was observed in electrical resistivity profiles, high-resolution conductivity, groundwater-level well measurements and through submarine groundwater discharge calculations. Depth-specific geochemical pore water measurements further assessed and confirmed the distinct boundaries between fresh and saline water masses in the aquifer. The identification of the freshwater lens’ saline boundaries is essential for a quantitative evaluation of the aquifers freshwater resources and help understand how these resources may be impacted by climate change and anthropogenic activities.

Physical and economic impacts of sea-level rise and low probability flooding events on coastal communities.

PubMed

Prime, Thomas; Brown, Jennifer M; Plater, Andrew J

2015-01-01

Conventionally flood mapping typically includes only a static water level (e.g. peak of a storm tide) in coastal flood inundation events. Additional factors become increasingly important when increased water-level thresholds are met during the combination of a storm tide and increased mean sea level. This research incorporates factors such as wave overtopping and river flow in a range of flood inundation scenarios of future sea-level projections for a UK case study of Fleetwood, northwest England. With increasing mean sea level it is shown that wave overtopping and river forcing have an important bearing on the cost of coastal flood events. The method presented converts inundation maps into monetary cost. This research demonstrates that under scenarios of joint extreme surge-wave-river events the cost of flooding can be increased by up to a factor of 8 compared with an increase in extent of up to a factor of 3 relative to "surge alone" event. This is due to different areas being exposed to different flood hazards and areas with common hazard where flood waters combine non-linearly. This shows that relying simply on flood extent and volume can under-predict the actual economic impact felt by a coastal community. Additionally, the scenario inundation depths have been presented as "brick course" maps, which represent a new way of interpreting flood maps. This is primarily aimed at stakeholders to increase levels of engagement within the coastal community.

PERSPECTIVE: The tripping points of sea level rise

NASA Astrophysics Data System (ADS)

Hecht, Alan D.

2009-12-01

When President Nixon created the US Environmental Protection Agency (EPA) in 1970 he said the environment must be perceived as a single, interrelated system. We are nowhere close to achieving this vision. Jim Titus and his colleagues [1] highlight one example of where one set of regulations or permits may be in conflict with another and where regulations were crafted in the absence of understanding the cumulative impact of global warming. The issue here is how to deal with the impacts of climate change on sea level and the latter's impact on wetland polices, clean water regulations, and ecosystem services. The Titus paper could also be called `The tripping points of sea level rise'. Titus and his colleagues have looked at the impact of such sea level rise on the east coast of the United States. Adaptive responses include costly large- scale investment in shore protection (e.g. dikes, sand replenishment) and/or ecosystem migration (retreat), where coastal ecosystems move inland. Shore protection is limited by available funds, while ecosystem migrations are limited by available land use. The driving factor is the high probability of sea level rise due to climate change. Estimating sea level rise is difficult because of local land and coastal dynamics including rising or falling land areas. It is estimated that sea level could rise between 8 inches and 2 feet by the end of this century [2]. The extensive data analysis done by Titus et al of current land use is important because, as they observe, `property owners and land use agencies have generally not decided how they will respond to sea level rise, nor have they prepared maps delineating where shore protection and retreat are likely'. This is the first of two `tripping points', namely the need for adaptive planning for a pending environmental challenge that will create economic and environment conflict among land owners, federal and state agencies, and businesses. One way to address this gap in adaptive management, according to Titus et al, is for communities to develop a common vision about which lands will be protected and which lands will yield to the rising sea, similar to the way land use plans identify commercial, residential, agricultural, and conservation lands. The supplementary material in their paper (as well as a related web site suggested by the peer review process of this journal) provides maps that depict the likelihood of shore protection based on existing land use data and the assessment of the local governments. Such maps, they suggest, might be used as a starting point to promote dialogue within communities about which lands should be protected and which lands are allowed to become submerged. A second tripping point relates to conflict between existing environmental laws and their collective ability to respond to the impacts of global warming. For example, property owners are automatically issued permits for construction of hard shore-protection structures (e.g. bulkheads and revetments) without an assessment of their environmental impact. Normally, under the Clean Water Act, the impact of each permit is assessed separately, but there is a special expedited process for activities with no cumulative impact. The Corps of Engineers concluded that shore protection does not have a cumulative impact, and that might be true if shore erosion was rare and stable shores the general rule. But once we recognize that the sea level is rising, then shore erosion becomes the general rule and a cumulative impact is likely. Under the National Environmental Protection Act (NEPA), cumulative impacts have been defined as `the impacts of an activity ``added to other past present and reasonably future actions'' regardless of who takes the other actions'. If the NEPA were actually evoked, it would considerably delay permit approvals and substantially impact the Corps of Engineers' process for issuing permits. The potential impact of sea level rise clearly requires a holistic approach to coastal management in which options for shore protection or retreats are clearly identified and where economic, ecosystem and social impacts can be clearly evaluated. At stake are both the future of wetlands that provide important ecosystem services and the safety and sustainability of our coastal communities. This is a huge challenge requiring adequate data, long-term planning, federal-state cooperation, and integration of environmental laws. The time is at hand to assess a business-as-usual response to sea level rise or to explore a more holistic and integrated approach. President Obama has said: `The threat from climate change is serious, it is urgent, and it is growing. Our generation's response to this challenge will be judged by history, for if we fail to meet it—boldly, swiftly, and together—we risk consigning future generations to an irreversible catastrophe' [3]. Though the President was talking about action to reduce emissions of greenhouse gases, cooperation to address the consequences of rising sea level and changing climate is just as urgent. References [1] Titus J G et al 2009 State and local governments plan for development of most land vulnerable to rising sea level along the US Atlantic coast Environ. Res. Lett. 4 044008 [2] US Global Change Research Program 2009 Global Climate Change Impacts in the United States (June 2009) [3] www.whitehouse.gov/the_press_office/Remarks-by-the-President-at-UN-Secretary-General-Ban-Ki-moons-Climate-Change-Summit/

Impact of climate change on Gironde Estuary

NASA Astrophysics Data System (ADS)

Laborie, Vanessya; Hissel, François; Sergent, Philippe

2014-05-01

Within the THESEUS European project, a simplified mathematical model for storm surge levels in the Bay of Biscay was adjusted on 10 events at Le Verdon using wind and pressure fields from CLM/SGA, so that the water levels at Le Verdon have the same statistic quantiles as observed tide records for the period [1960-2000]. The analysis of future storm surge levels shows a decrease in their quantiles at Le Verdon, whereas there is an increase of the quantiles of total water levels. This increase is smaller than the sea level rise and gets even smaller as one enters farther upstream in the estuary. A numerical model of the Gironde Estuary was then used to evaluate future water levels at 6 locations of the estuary from Le Verdon to Bordeaux and to assess the changes in the quantiles of water levels during the XXIst century using ONERC's pessimistic scenario for sea level rise (60 cm). The model was fed by several data sources : wind fields at Royan and Mérignac interpolated from the grid of the European Climatolologic Model CLM/SGA, a tide signal at Le Verdon, the discharges of Garonne (at La Réole), the Dordogne (at Pessac) and Isle (at Libourne). A series of flood maps for different return periods between 2 and 100 years and for four time periods ([1960-1999], [2010-2039], [2040-2069] and [2070-2099]) have been built for the region of Bordeaux. Quantiles of water levels in the floodplain have also been calculated. The impact of climate change on the evolution of flooded areas in the Gironde Estuary and on quantiles of water levels in the floodplain mainly depends on the sea level rise. Areas which are not currently flooded for low return periods will be inundated in 2100. The influence of river discharges and dike breaching should also be taken into account for more accurate results.

Impact of the 3 °C temperature rise on bacterial growth and carbon transfer towards higher trophic levels: Empirical models for the Adriatic Sea

NASA Astrophysics Data System (ADS)

Šolić, Mladen; Krstulović, Nada; Šantić, Danijela; Šestanović, Stefanija; Kušpilić, Grozdan; Bojanić, Natalia; Ordulj, Marin; Jozić, Slaven; Vrdoljak, Ana

2017-09-01

The Mediterranean Sea (including the Adriatic Sea) has been identified as a 'hotspot' for climate change, with the prediction of the increase in water temperature of 2-4 °C over the next few decades. Being mainly oligotrophic, and strongly phosphorus limited, the Adriatic Sea is characterized by the important role of the microbial food web in production and transfer of biomass and energy towards higher trophic levels. We hypothesized that predicted 3 °C temperature rise in the near future might cause an increase of bacterial production and bacterial losses to grazers, which could significantly enlarge the trophic base for metazoans. This empirical study is based on a combined 'space-for-time substitution' analysis (which is performed on 3583 data sets) and on an experimental approach (36 in situ grazing experiments performed at different temperatures). It showed that the predicted 3 °C temperature increase (which is a result of global warming) in the near future could cause a significant increase in bacterial growth at temperatures lower than 16 °C (during the colder winter-spring period, as well as in the deeper layers). The effect of temperature on bacterial growth could be additionally doubled in conditions without phosphorus limitation. Furthermore, a 3 °C increase in temperature could double the grazing on bacteria by heterotrophic nanoflagellate (HNF) and ciliate predators and it could increase the proportion of bacterial production transferred to the metazoan food web by 42%. Therefore, it is expected that global warming may further strengthen the role of the microbial food web in a carbon cycle in the Adriatic Sea.

Unveiling climate and ice-sheet history from drilling in high-latitude margins and future perspectives

NASA Astrophysics Data System (ADS)

Escutia Dotti, Carlota

2010-05-01

Polar ice is an important component of the climate system, affecting global sea level, ocean circulation and heat transport, marine productivity, and albedo. During the last decades drilling in the Arctic (IODP ACEX and Bering Expeditions) and in Antarctica (ODP Legs 178, 188, IODP Expedition 318 and ANDRILL) has revealed regional information about sea ice and ice sheets development and evolution. Integration of this data with numerical modeling provide an understanding of the early development of the ice sheets and their variability through the Cenozoic. Much of this work points to atmospheric CO2 and other greenhouse gases concentrations as important triggering mechanism driving the onset of glaciation and subsequent ice volume variability. With current increasing atmospheric greenhouse gases concentrations resulting in rapidly rising global temperatures, studies of polar climates become increasingly prominent on the research agenda. Despite of the relevance of the high-latitudes in the global climate systems, the short- and long-term history of the ice sheets and sea-ice and its relationships with paleoclimatic, paleoceanographic, and sea level changes is still poorly understood. A multinational, multiplatform scientific drilling strategy is being developed to recover key physical evidence from selected high-latitude areas. This strategy is aimed at addressing key knowledge gaps about the role of polar ice in climate change, targeting questions such as timing of events, rates of change, tipping points, regional variations, and northern vs. southern hemispheres (in phase or out-of-phase) variability. This data is critical to provide constrains to sea-ice and ice sheet models, which are the basis for forecasting the future of the cryosphere in a warming world.

Reactivation of Kamb Ice Stream tributaries triggers century-scale reorganization of Siple Coast ice flow in West Antarctica

DOE PAGES

Bougamont, M.; Christoffersen, P.; Price, S. F.; ...

2015-10-21

Ongoing, centennial-scale flow variability within the Ross ice streams of West Antarctica suggests that the present-day positive mass balance in this region may reverse in the future. Here we use a three-dimensional ice sheet model to simulate ice flow in this region over 250 years. The flow responds to changing basal properties, as a subglacial till layer interacts with water transported in an active subglacial hydrological system. We show that a persistent weak bed beneath the tributaries of the dormant Kamb Ice Stream is a source of internal ice flow instability, which reorganizes all ice streams in this region, leadingmore » to a reduced (positive) mass balance within decades and a net loss of ice within two centuries. This hitherto unaccounted for flow variability could raise sea level by 5 mm this century. Furthermore, better constraints on future sea level change from this region will require improved estimates of geothermal heat flux and subglacial water transport.« less

Climate projection of synoptic patterns forming extremely high wind speed over the Barents Sea

NASA Astrophysics Data System (ADS)

Surkova, Galina; Krylov, Aleksey

2017-04-01

Frequency of extreme weather events is not very high, but their consequences for the human well-being may be hazardous. These seldom events are not always well simulated by climate models directly. Sometimes it is more effective to analyze numerical projection of large-scale synoptic event generating extreme weather. For example, in mid-latitude surface wind speed depends mainly on the sea level pressure (SLP) field - its configuration and horizontal pressure gradient. This idea was implemented for analysis of extreme wind speed events over the Barents Sea. The calendar of high surface wind speed V (10 m above the surface) was prepared for events with V exceeding 99th percentile value in the central part of the Barents Sea. Analysis of probability distribution function of V was carried out on the base of ERA-Interim reanalysis data (6-hours, 0.75x0.75 degrees of latitude and longitude) for the period 1981-2010. Storm wind events number was found to be 240 days. Sea level pressure field over the sea and surrounding area was selected for each storm wind event. For the climate of the future (scenario RCP8.5), projections of SLP from CMIP5 numerical experiments were used. More than 20 climate models results of projected SLP (2006-2100) over the Barents Sea were correlated with modern storm wind SLP fields. Our calculations showed the positive tendency of annual frequency of storm SLP patterns over the Barents Sea by the end of 21st century.

Assessing storm surge hazard and impact of sea level rise in the Lesser Antilles case study of Martinique

NASA Astrophysics Data System (ADS)

Krien, Yann; Dudon, Bernard; Roger, Jean; Arnaud, Gael; Zahibo, Narcisse

2017-09-01

In the Lesser Antilles, coastal inundations from hurricane-induced storm surges pose a great threat to lives, properties and ecosystems. Assessing current and future storm surge hazards with sufficient spatial resolution is of primary interest to help coastal planners and decision makers develop mitigation and adaptation measures. Here, we use wave-current numerical models and statistical methods to investigate worst case scenarios and 100-year surge levels for the case study of Martinique under present climate or considering a potential sea level rise. Results confirm that the wave setup plays a major role in the Lesser Antilles, where the narrow island shelf impedes the piling-up of large amounts of wind-driven water on the shoreline during extreme events. The radiation stress gradients thus contribute significantly to the total surge - up to 100 % in some cases. The nonlinear interactions of sea level rise (SLR) with bathymetry and topography are generally found to be relatively small in Martinique but can reach several tens of centimeters in low-lying areas where the inundation extent is strongly enhanced compared to present conditions. These findings further emphasize the importance of waves for developing operational storm surge warning systems in the Lesser Antilles and encourage caution when using static methods to assess the impact of sea level rise on storm surge hazard.

Impacts of sea-level rise on the Moroccan coastal zone: Quantifying coastal erosion and flooding in the Tangier Bay

NASA Astrophysics Data System (ADS)

Snoussi, Maria; Ouchani, Tachfine; Khouakhi, Abdou; Niang-Diop, Isabelle

2009-06-01

As part of a broad assessment of climate change impacts in Morocco, an assessment of vulnerability and adaptation of coastal zones to sea-level rise was conducted. Tangier Bay which is the most important socio-economic pole in Northern Morocco represents one of the cases studies. Using a GIS-based inundation analysis and an erosion modelling approach, the potential physical vulnerability to accelerated sea-level rise was investigated, and the most vulnerable socio-economic sectors were assessed. Results indicate that 10% and 24% of the area will be at risk of flooding respectively for minimum (4 m) and maximum (11 m) inundation levels. The most severely impacted sectors are expected to be the coastal defences and the port, the urban area, tourist coastal infrastructures, the railway, and the industrial area. Shoreline erosion would affect nearly 20% and 45% of the total beach areas respectively in 2050 and 2100. Potential response strategies and adaptation options identified include: sand dune fixation, beach nourishment and building of seawalls to protect the urban and industrial areas of high value. It was also recommended that an Integrated Coastal Zone Management Plan for the region, including upgrading awareness, building regulation and urban growth planning should be the most appropriate tool to ensure a long-term sustainable development, while addressing the vulnerability of the coast to future sea-level rise.

Importance of coastal change variables in determining vulnerability to sea- and lake-level change

USGS Publications Warehouse

Pendleton, E.A.; Thieler, E.R.; Williams, S.J.

2010-01-01

In 2001, the U.S. Geological Survey began conducting scientific assessments of coastal vulnerability to potential future sea- and lake-level changes in 22 National Park Service sea- and lakeshore units. Coastal park units chosen for the assessment included a variety of geological and physical settings along the U.S. Atlantic, Pacific, Gulf of Mexico, Gulf of Alaska, Caribbean, and Great Lakes shorelines. This research is motivated by the need to understand and anticipate coastal changes caused by accelerating sea-level rise, as well as lake-level changes caused by climate change, over the next century. The goal of these assessments is to provide information that can be used to make long-term (decade to century) management decisions. Here we analyze the results of coastal vulnerability assessments for several coastal national park units. Index-based assessments quantify the likelihood that physical changes may occur based on analysis of the following variables: tidal range, ice cover, wave height, coastal slope, historical shoreline change rate, geomorphology, and historical rate of relative sea- or lake-level change. This approach seeks to combine a coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, and it provides a measure of the system's potential vulnerability to the effects of sea- or lake-level change. Assessments for 22 park units are combined to evaluate relationships among the variables used to derive the index. Results indicate that Atlantic and Gulf of Mexico parks have the highest vulnerability rankings relative to other park regions. A principal component analysis reveals that 99% of the index variability can be explained by four variables: geomorphology, regional coastal slope, water-level change rate, and mean significant wave height. Tidal range, ice cover, and historical shoreline change are not as important when the index is evaluated at large spatial scales (thousands of kilometers). ?? 2010 Coastal Education and Research Foundation.

Future export of particulate and dissolved organic carbon from land to coastal zones of the Baltic Sea

NASA Astrophysics Data System (ADS)

Strååt, Kim Dahlgren; Mörth, Carl-Magnus; Undeman, Emma

2018-01-01

The Baltic Sea is a semi-enclosed brackish sea in Northern Europe with a drainage basin four times larger than the sea itself. Riverine organic carbon (Particulate Organic Carbon, POC and Dissolved Organic Carbon, DOC) dominates carbon input to the Baltic Sea and influences both land-to-sea transport of nutrients and contaminants, and hence the functioning of the coastal ecosystem. The potential impact of future climate change on loads of POC and DOC in the Baltic Sea drainage basin (BSDB) was assessed using a hydrological-biogeochemical model (CSIM). The changes in annual and seasonal concentrations and loads of both POC and DOC by the end of this century were predicted using three climate change scenarios and compared to the current state. In all scenarios, overall increasing DOC loads, but unchanged POC loads, were projected in the north. In the southern part of the BSDB, predicted DOC loads were not significantly changing over time, although POC loads decreased in all scenarios. The magnitude and significance of the trends varied with scenario but the sign (+ or -) of the projected trends for the entire simulation period never conflicted. Results were discussed in detail for the "middle" CO2 emission scenario (business as usual, a1b). On an annual and entire drainage basin scale, the total POC load was projected to decrease by ca 7% under this scenario, mainly due to reduced riverine primary production in the southern parts of the BSDB. The average total DOC load was not predicted to change significantly between years 2010 and 2100 due to counteracting decreasing and increasing trends of DOC loads to the six major sub-basins in the Baltic Sea. However, predicted seasonal total loads of POC and DOC increased significantly by ca 46% and 30% in winter and decreased by 8% and 21% in summer over time, respectively. For POC the change in winter loads was a consequence of increasing soil erosion and a shift in duration of snowfall and onset of the spring flood impacting the input of terrestrial litter, while reduced primary production mainly explained the differences predicted in summer. The simulations also showed that future changes in POC and DOC export can vary significantly across the different sub-basins of the Baltic Sea. These changes in organic carbon input may impact future coastal food web structures e.g. by influencing bacterial and phytoplankton production in coastal zones, which in turn may have consequences at higher trophic levels.

Pressures, trends, and impacts in coastal zones: Interactions between socioeconomic and natural systems

NASA Astrophysics Data System (ADS)

Turner, R. K.; Subak, S.; Adger, W. N.

1996-03-01

This paper assesses the status of coastal zones in the context of expected climate change and its related impacts, as well as current and future socioeconomic pressures and impacts. It is argued that external stresses and shocks relating to sea-level rise and other changes will tend to exacerbate existing environmental pressures and damage in coastal zones. Coastal zones are under increasing stress because of an interrelated set of planning failures including information, economic market, and policy intervention failures. Moves towards integrated coastal zone management are urgently required to guide the coevolution of natural and human systems. Overtly technocentric claims that assessments of vulnerability undertaken to date are overestimates of likely future damages from global warming are premature. While it is the case that forecasts of sea-level rise have been scaled down, much uncertainty remains over, for example, combined storm, sea surge, and other events. In any case, within the socioeconomic analyses of the problem, resource valuations have been at best only partial and have failed to incorporate sensitivity analysis in terms of the discount rates utilized. This would indicate an underestimation of potential damage costs. Overall, a precautionary approach is justified based on the need to act ahead of adequate information acquisition, economically efficient resource pricing and proactive coastal planning.

Sensitivity of the global submarine hydrate inventory to scenarios of future climate change

NASA Astrophysics Data System (ADS)

Hunter, S. J.; Goldobin, D. S.; Haywood, A. M.; Ridgwell, A.; Rees, J. G.

2013-04-01

The global submarine inventory of methane hydrate is thought to be considerable. The stability of marine hydrates is sensitive to changes in temperature and pressure and once destabilised, hydrates release methane into sediments and ocean and potentially into the atmosphere, creating a positive feedback with climate change. Here we present results from a multi-model study investigating how the methane hydrate inventory dynamically responds to different scenarios of future climate and sea level change. The results indicate that a warming-induced reduction is dominant even when assuming rather extreme rates of sea level rise (up to 20 mm yr-1) under moderate warming scenarios (RCP 4.5). Over the next century modelled hydrate dissociation is focussed in the top ˜100m of Arctic and Subarctic sediments beneath <500m water depth. Predicted dissociation rates are particularly sensitive to the modelled vertical hydrate distribution within sediments. Under the worst case business-as-usual scenario (RCP 8.5), upper estimates of resulting global sea-floor methane fluxes could exceed estimates of natural global fluxes by 2100 (>30-50TgCH4yr-1), although subsequent oxidation in the water column could reduce peak atmospheric release rates to 0.75-1.4 Tg CH4 yr-1.

Comparative Synthesis of Current and Future Urban Stormwater Runoff Scenarios in Tampa Bay Basin under a Changing Climate

NASA Astrophysics Data System (ADS)

Khan, M.; Abdul-Aziz, O. I.

2016-12-01

Changes in climatic regimes and basin characteristics such as imperviousness, roughness and land use types would lead to potential changes in stormwater budget. In this study we quantified reference sensitivities of stormwater runoff to the potential climatic and land use/cover changes by developing a large-scale, mechanistic rainfall-runoff model for the Tampa Bay Basin of Florida using the US EPA Storm Water Management Model (SWMM 5.1). Key processes of urban hydrology, its dynamic interactions with groundwater and sea level, hydro-climatic variables and land use/cover characteristics were incorporated within the model. The model was calibrated and validated with historical streamflow data. We then computed the historical (1970-2000) and potential 2050s stormwater budgets for the Tampa Bay Basin. Climatic scenario projected by the global climate models (GCMs) and the regional climate models (RCMs), along with sea level and land use/cover projections, were utilized to anticipate the future stormwater budget. The comparative assessment of current and future stormwater scenario will aid a proactive management of stormwater runoff under a changing climate in the Tampa Bay Basin and similar urban basins around the world.

Persistent Cold Air Outbreaks over North America Under Climate Warming

NASA Astrophysics Data System (ADS)

Gao, Y.; Leung, L. R.; Lu, J.

2014-12-01

This study evaluates the change of cold air outbreaks (CAO) over North America using Coupled Model Intercomparison Project Phase 5 (CMIP5) multi-model ensemble of global climate simulations as well as regional high resolution climate simulations. In future, while robust decrease of CAO duration dominates in most of the North America, the decrease over northwestern U.S. was found to have much smaller magnitude than the surrounding regions. We found statistically significant increase of the sea level pressure over gulf of Alaska, leading to the advection of cold air to northwestern U.S.. By shifting the probability distribution of present temperature towards future warmer conditions, we identified the changes in large scale circulation contribute to about 50% of the enhanced sea level pressure. Using the high resolution regional climate model results, we found that increases of existing snowpack could potentially trigger the increase of CAO in the near future over the southwestern U.S. and Rocky Mountain through surface albedo effects. By the end of this century, the top 5 most extreme historical CAO events may still occur and wind chill warning will continue to have societal impacts over North America in particular over northwestern United States.

The Last Interglacial in the Levant: Perspective from the ICDP Dead Sea Deep Drill Core

NASA Astrophysics Data System (ADS)

Goldstein, S. L.; Torfstein, A.; Stein, M.; Kushnir, Y.; Enzel, Y.; Haug, G. H.

2014-12-01

Sediments recovered by the ICDP Dead Sea Deep Drilling Project provide a new perspective on the climate history of the Levant during the last interglacial period MIS5. They record the extreme impacts of an intense interglacial characterized by stronger insolation, warmer mean global temperatures, and higher sea-levels than the Holocene. Results show both extreme hyper-aridity during MIS5e, including an unprecedented drawdown of Dead Sea water levels, and the impacts of a strong precession-driven African monsoon responsible for a major sapropel event (S5) in the eastern Mediterranean. Hyper-arid conditions at the beginning of MIS5e prior to S5 (~132-128 ka) are evidenced by halite deposition, indicating declining Dead Sea lake levels. Surprisingly, the hyper-arid phase is interrupted during the MIS5e peak (~128-120 ka), coinciding with the S5 sapropel, which is characterized by a thick (23 m) section of silty detritus (without any halite) whose provenance indicates southern-sourced wetness in the watershed. Upon weakening of the S5 monsoon (~120-115 ka), the return of extreme aridity resulted in an unprecedented lake level drawdown, reflected by massive salt deposition, and followed by a sediment hiatus (~115-100 ka) indicating prolonged low lake level. The resumption of section follows classic Levant patterns with more wetness during cooler MIS5b and hyper-aridity during warmer MIS5a. The ICDP core provides the first evidence for a direct linkage between an intense precession-driven African monsoon and wetness at the high subtropical latitude (~30N) of the Dead Sea watershed. Combined with coeval deposition of Negev speleothems and travertines, and calcitification of Red Sea corals, the evidence indicates a wet climatic corridor that could facilitate homo sapiens migration out of Africa during the MIS5e peak. In addition, the MIS 5e hyper-arid intervals may provide an important cautionary analogue for the impact of future warming on regional water resources.

Plastic litter in sediments from a marine area likely to become protected (Aeolian Archipelago's islands, Tyrrhenian sea).

PubMed

Fastelli, Paolo; Blašković, Andrea; Bernardi, Giulia; Romeo, Teresa; Čižmek, Hrvoje; Andaloro, Franco; Russo, Giovanni F; Guerranti, Cristiana; Renzi, Monia

2016-12-15

This research aims to define for the first time levels and patterns of different litter groups (macro, meso and microplastics) in sediments from a marine area designed for the institution of a new marine protected area (Aeolian Archipelago, Italy). Microplastics resulted the principal group and found in all samples analyzed, with shape and colours variable between different sampling sites. MPs levels measured in this study are similar to values recorded in harbour sites and lower than reported in Adriatic Sea, while macroplastics levels are notably lower than in harbor sites. Sediment grain-size and island extent resulted not significant in determining levels and distribution of plastic debris among islands. In the future, following the establishment of the MPA in the study area, these basic data will be useful to check for potential protective effects on the levels and distribution of plastic debris. Copyright © 2016 Elsevier Ltd. All rights reserved.

Leveling

USGS Publications Warehouse

1966-01-01

Geodetic leveling by the U.S. Geological Survey provides a framework of accurate elevations for topographic mapping. Elevations are referred to the Sea Level Datum of 1929. Lines of leveling may be run either with automatic or with precise spirit levels, by either the center-wire or the three-wire method. For future use, the surveys are monumented with bench marks, using standard metal tablets or other marking devices. The elevations are adjusted by least squares or other suitable method and are published in lists of control.

Evolving Understanding of Antarctic Ice-Sheet Physics and Ambiguity in Probabilistic Sea-Level Projections

NASA Astrophysics Data System (ADS)

Kopp, Robert E.; DeConto, Robert M.; Bader, Daniel A.; Hay, Carling C.; Horton, Radley M.; Kulp, Scott; Oppenheimer, Michael; Pollard, David; Strauss, Benjamin H.

2017-12-01

Mechanisms such as ice-shelf hydrofracturing and ice-cliff collapse may rapidly increase discharge from marine-based ice sheets. Here, we link a probabilistic framework for sea-level projections to a small ensemble of Antarctic ice-sheet (AIS) simulations incorporating these physical processes to explore their influence on global-mean sea-level (GMSL) and relative sea-level (RSL). We compare the new projections to past results using expert assessment and structured expert elicitation about AIS changes. Under high greenhouse gas emissions (Representative Concentration Pathway [RCP] 8.5), median projected 21st century GMSL rise increases from 79 to 146 cm. Without protective measures, revised median RSL projections would by 2100 submerge land currently home to 153 million people, an increase of 44 million. The use of a physical model, rather than simple parameterizations assuming constant acceleration of ice loss, increases forcing sensitivity: overlap between the central 90% of simulations for 2100 for RCP 8.5 (93-243 cm) and RCP 2.6 (26-98 cm) is minimal. By 2300, the gap between median GMSL estimates for RCP 8.5 and RCP 2.6 reaches >10 m, with median RSL projections for RCP 8.5 jeopardizing land now occupied by 950 million people (versus 167 million for RCP 2.6). The minimal correlation between the contribution of AIS to GMSL by 2050 and that in 2100 and beyond implies current sea-level observations cannot exclude future extreme outcomes. The sensitivity of post-2050 projections to deeply uncertain physics highlights the need for robust decision and adaptive management frameworks.

On the Application of Science Systems Engineering and Uncertainty Quantification for Ice Sheet Science and Sea Level Projections

NASA Astrophysics Data System (ADS)

Schlegel, Nicole-Jeanne; Boening, Carmen; Larour, Eric; Limonadi, Daniel; Schodlok, Michael; Seroussi, Helene; Watkins, Michael

2017-04-01

Research and development activities at the Jet Propulsion Laboratory (JPL) currently support the creation of a framework to formally evaluate the observational needs within earth system science. One of the pilot projects of this effort aims to quantify uncertainties in global mean sea level rise projections, due to contributions from the continental ice sheets. Here, we take advantage of established uncertainty quantification tools embedded within the JPL-University of California at Irvine Ice Sheet System Model (ISSM). We conduct sensitivity and Monte-Carlo style sampling experiments on forward simulations of the Greenland and Antarctic ice sheets. By varying internal parameters and boundary conditions of the system over both extreme and credible worst-case ranges, we assess the impact of the different parameter ranges on century-scale sea level rise projections. The results inform efforts to a) isolate the processes and inputs that are most responsible for determining ice sheet contribution to sea level; b) redefine uncertainty brackets for century-scale projections; and c) provide a prioritized list of measurements, along with quantitative information on spatial and temporal resolution, required for reducing uncertainty in future sea level rise projections. Results indicate that ice sheet mass loss is dependent on the spatial resolution of key boundary conditions - such as bedrock topography and melt rates at the ice-ocean interface. This work is performed at and supported by the California Institute of Technology's Jet Propulsion Laboratory. Supercomputing time is also supported through a contract with the National Aeronautics and Space Administration's Cryosphere program.

Evolving Understanding of Antarctic Ice-Sheet Physics and Ambiguity in Probabilistic Sea-Level Projections

NASA Technical Reports Server (NTRS)

Kopp, Robert E.; DeConto, Robert M.; Bader, Daniel A.; Hay, Carling C.; Horton, Radley M.; Kulp, Scott; Oppenheimer, Michael; Pollard, David; Strauss, Benjamin

2017-01-01

Mechanisms such as ice-shelf hydrofracturing and ice-cliff collapse may rapidly increase discharge from marine-based ice sheets. Here, we link a probabilistic framework for sea-level projections to a small ensemble of Antarctic ice-sheet (AIS) simulations incorporating these physical processes to explore their influence on global-mean sea-level (GMSL) and relative sea-level (RSL). We compare the new projections to past results using expert assessment and structured expert elicitation about AIS changes. Under high greenhouse gas emissions (Representative Concentration Pathway [RCP] 8.5), median projected 21st century GMSL rise increases from 79 to 146 cm. Without protective measures, revised median RSL projections would by 2100 submerge land currently home to 153 million people, an increase of 44 million. The use of a physical model, rather than simple parameterizations assuming constant acceleration of ice loss, increases forcing sensitivity: overlap between the central 90% of simulations for 2100 for RCP 8.5 (93-243 cm) and RCP 2.6 (26-98 cm) is minimal. By 2300, the gap between median GMSL estimates for RCP 8.5 and RCP 2.6 reaches >10 m, with median RSL projections for RCP 8.5 jeopardizing land now occupied by 950 million people (versus 167 million for RCP 2.6). The minimal correlation between the contribution of AIS to GMSL by 2050 and that in 2100 and beyond implies current sea-level observations cannot exclude future extreme outcomes. The sensitivity of post-2050 projections to deeply uncertain physics highlights the need for robust decision and adaptive management frameworks.

Sea-level rise impacts on the tides of the European Shelf

NASA Astrophysics Data System (ADS)

Idier, Déborah; Paris, François; Cozannet, Gonéri Le; Boulahya, Faiza; Dumas, Franck

2017-04-01

Sea-level rise (SLR) can modify not only total water levels, but also tidal dynamics. Several studies have investigated the effects of SLR on the tides of the western European continental shelf (mainly the M2 component). We further investigate this issue using a modelling-based approach, considering uniform SLR scenarios from -0.25 m to +10 m above present-day sea level. Assuming that coastal defenses are constructed along present-day shorelines, the patterns of change in high tide levels (annual maximum water level) are spatially similar, regardless of the magnitude of sea-level rise (i.e., the sign of the change remains the same, regardless of the SLR scenario) over most of the area (70%). Notable increases in high tide levels occur especially in the northern Irish Sea, the southern part of the North Sea and the German Bight, and decreases occur mainly in the western English Channel. These changes are generally proportional to SLR, as long as SLR remains smaller than 2 m. Depending on the location, they can account for +/-15% of regional SLR. High tide levels and the M2 component exhibit slightly different patterns. Analysis of the 12 largest tidal components highlights the need to take into account at least the M2, S2, N2, M4, MS4 and MN4 components when investigating the effects of SLR on tides. Changes in high tide levels are much less proportional to SLR when flooding is allowed, in particular in the German Bight. However, some areas (e.g., the English Channel) are not very sensitive to this option, meaning that the effects of SLR would be predictable in these areas, even if future coastal defense strategies are ignored. Physically, SLR-induced tidal changes result from the competition between reductions in bed friction damping, changes in resonance properties and increased reflection at the coast, i.e., local and non-local processes. A preliminary estimate of tidal changes by 2100 under a plausible non-uniform SLR scenario (using the RCP4.5 scenario) is provided. Though the changes display similar patterns, the high water levels appear to be sensitive to the non-uniformity of SLR.

A Bayesian network approach to predicting nest presence of thefederally-threatened piping plover (Charadrius melodus) using barrier island features

USGS Publications Warehouse

Gieder, Katherina D.; Karpanty, Sarah M.; Fraser, James D.; Catlin, Daniel H.; Gutierrez, Benjamin T.; Plant, Nathaniel G.; Turecek, Aaron M.; Thieler, E. Robert

2014-01-01

Sea-level rise and human development pose significant threats to shorebirds, particularly for species that utilize barrier island habitat. The piping plover (Charadrius melodus) is a federally-listed shorebird that nests on barrier islands and rapidly responds to changes in its physical environment, making it an excellent species with which to model how shorebird species may respond to habitat change related to sea-level rise and human development. The uncertainty and complexity in predicting sea-level rise, the responses of barrier island habitats to sea-level rise, and the responses of species to sea-level rise and human development necessitate a modelling approach that can link species to the physical habitat features that will be altered by changes in sea level and human development. We used a Bayesian network framework to develop a model that links piping plover nest presence to the physical features of their nesting habitat on a barrier island that is impacted by sea-level rise and human development, using three years of data (1999, 2002, and 2008) from Assateague Island National Seashore in Maryland. Our model performance results showed that we were able to successfully predict nest presence given a wide range of physical conditions within the model’s dataset. We found that model predictions were more successful when the range of physical conditions included in model development was varied rather than when those physical conditions were narrow. We also found that all model predictions had fewer false negatives (nests predicted to be absent when they were actually present in the dataset) than false positives (nests predicted to be present when they were actually absent in the dataset), indicating that our model correctly predicted nest presence better than nest absence. These results indicated that our approach of using a Bayesian network to link specific physical features to nest presence will be useful for modelling impacts of sea-level rise- or human-related habitat change on barrier islands. We recommend that potential users of this method utilize multiple years of data that represent a wide range of physical conditions in model development, because the model performed less well when constructed using a narrow range of physical conditions. Further, given that there will always be some uncertainty in predictions of future physical habitat conditions related to sea-level rise and/or human development, predictive models will perform best when developed using multiple, varied years of data input.

Projected Sea Level Rise and Changes in Extreme Storm Surge and Wave Events During the 21st Century in the Region of Singapore

NASA Astrophysics Data System (ADS)

Palmer, M. D.; Cannaby, H.; Howard, T.; Bricheno, L.

2016-02-01

Singapore is an island state with considerable population, industries, commerce and transport located in coastal areas at elevations less than 2 m making it vulnerable to sea-level rise. Mitigation against future inundation events requires a quantitative assessment of risk. To address this need, regional projections of changes in (i) long-term mean sea level and (ii) the frequency of extreme storm surge and wave events have been combined to explore potential changes to coastal flood risk over the 21st century. Local changes in time mean sea level were evaluated using the process-based climate model data and methods presented in the IPCC AR5. Regional surge and wave solutions extending from 1980 to 2100 were generated using 12 km resolution surge (Nucleus for European Modelling of the Ocean - NEMO) and wave (WaveWatchIII) models. Ocean simulations were forced by output from a selection of four downscaled ( 12 km resolution) atmospheric models, forced at the lateral boundaries by global climate model simulations generated for the IPCC AR5. Long-term trends in skew surge and significant wave height were then assessed using a generalised extreme value model, fit to the largest modelled events each year. An additional atmospheric solution downscaled from the ERA-Interim global reanalysis was used to force historical ocean model simulations extending from 1980-2010, enabling a quantitative assessment of model skill. Simulated historical sea surface height and significant wave height time series were compared to tide gauge data and satellite altimetry data respectively. Central estimates of the long-term mean sea level rise at Singapore by 2100 were projected to be 0.52 m(0.74 m) under the RCP 4.5(8.5) scenarios respectively. Trends in surge and significant wave height 2-year return levels were found to be statistically insignificant and/or physically very small under the more severe RCP8.5 scenario. We conclude that changes to long-term mean sea level constitute the dominant signal of change to the projected inundation risk for Singapore during the 21st century. We note that the largest recorded surge residual in the Singapore Strait of 84 cm lies between the central and upper estimates of sea level rise by 2100, highlighting the vulnerability of the region.

Projected sea level rise and changes in extreme storm surge and wave events during the 21st century in the region of Singapore

NASA Astrophysics Data System (ADS)

Cannaby, H.; Palmer, M. D.; Howard, T.; Bricheno, L.; Calvert, D.; Krijnen, J.; Wood, R.; Tinker, J.; Bunney, C.; Harle, J.; Saulter, A.; O'Neill, C.; Bellingham, C.; Lowe, J.

2015-12-01

Singapore is an island state with considerable population, industries, commerce and transport located in coastal areas at elevations less than 2 m making it vulnerable to sea-level rise. Mitigation against future inundation events requires a quantitative assessment of risk. To address this need, regional projections of changes in (i) long-term mean sea level and (ii) the frequency of extreme storm surge and wave events have been combined to explore potential changes to coastal flood risk over the 21st century. Local changes in time mean sea level were evaluated using the process-based climate model data and methods presented in the IPCC AR5. Regional surge and wave solutions extending from 1980 to 2100 were generated using ~ 12 km resolution surge (Nucleus for European Modelling of the Ocean - NEMO) and wave (WaveWatchIII) models. Ocean simulations were forced by output from a selection of four downscaled (~ 12 km resolution) atmospheric models, forced at the lateral boundaries by global climate model simulations generated for the IPCC AR5. Long-term trends in skew surge and significant wave height were then assessed using a generalised extreme value model, fit to the largest modelled events each year. An additional atmospheric solution downscaled from the ERA-Interim global reanalysis was used to force historical ocean model simulations extending from 1980-2010, enabling a quantitative assessment of model skill. Simulated historical sea surface height and significant wave height time series were compared to tide gauge data and satellite altimetry data respectively. Central estimates of the long-term mean sea level rise at Singapore by 2100 were projected to be 0.52 m (0.74 m) under the RCP 4.5 (8.5) scenarios respectively. Trends in surge and significant wave height 2 year return levels were found to be statistically insignificant and/or physically very small under the more severe RCP8.5 scenario. We conclude that changes to long-term mean sea level constitute the dominant signal of change to the projected inundation risk for Singapore during the 21st century. We note that the largest recorded surge residual in the Singapore Strait of ~ 84 cm lies between the central and upper estimates of sea level rise by 2100, highlighting the vulnerability of the region.

Ground-Penetrating Radar Study of Fort Morgan Peninsula Holocene Beach Ridges as Sea-level Indicators

NASA Astrophysics Data System (ADS)

Philbin, A.; Frederick, B.; Blum, M. D.; Tsoflias, G. P.

2017-12-01

Holocene sea-level change along the northern Gulf of Mexico (GoM) coast is controversial. One view interprets basal peats from the Mississippi Delta to indicate continual sea-level (SL) rise for the GoM as a whole. An alternate view proposes that data from the subsiding delta is primarily a subsidence signal, and that sandy non-deltaic shorelines indicate that regional SL reached present elevations by the middle Holocene, with minor oscillations since then. In fact, new regional long-term subsidence records from biostratigraphic indicators display significant subsidence in deltaic areas where basal-peat data were collected, and negligible rates along the GoM shoreline to the east. However, the use of sandy progradational shorelines, commonly known as "beach ridge systems", has been criticized for a lack of precise sea-level indicators, and therefore discounted. This research focuses on developing Holocene progradational sandy shorelines along the Alabama coast in the eastern GoM as SL indicators. Sandy shorelines in this area are ideal to examine SL change because they are well preserved, sufficiently distant from the subsiding delta, well mapped, and ages are known from previous work. Two-dimensional ground-penetrating radar imaging of well-dated beach-ridge successions is used here to examine and identify changes through time in the elevation of the shoreface clinoform topset-foreset break, which represents the transition between flat-lying foreshore and seaward-dipping shoreface facies, and forms in the intertidal zone. Beach-ridge successions with optical luminescence ages of ca. 5500-4800 yrs BP display topset-foreset breaks at current mean sea-level elevation, whereas beach-ridge successions from ca. 3500-2400 yrs BP display topset-foreset breaks that are 1 m above present mean SL and the elevation of modern topset-foreset breaks. These data support the view that current sea-level was reached by the middle Holocene, and was higher than present for at least one protracted period in the late Holocene. In addition to contributing to our understanding of Holocene SL change for the eastern GoM, results of this research provide context for sea-level conditions during which the Mississippi delta was constructed, and may provide insight into future shoreline response to rising sea levels.

Variation in winter diet of southern Beaufort Sea polar bears inferred from stable isotope analysis

USGS Publications Warehouse

Bentzen, T.W.; Follmann, Erich H.; Amstrup, Steven C.; York, G.S.; Wooller, M.J.; O'Hara, T. M.

2007-01-01

Ringed seals (Phoca hispida Schreber, 1775 = Pusa hispida (Schreber, 1775)) and bearded seals (Erignathus barbatus (Erxleben, 1777)) represent the majority of the polar bear (Ursus maritimus Phipps, 1774) annual diet. However, remains of lower trophic level bowhead whales (Balaena mysticetus L., 1758) are available in the southern Beaufort Sea and their dietary contribution to polar bears has been unknown. We used stable isotope (13C/12C, δ13C, 15N/14N, and δ15N) analysis to determine the diet composition of polar bears sampled along Alaska’s Beaufort Sea coast in March and April 2003 and 2004. The mean δ15N values of polar bear blood cells were 19.5‰ (SD = 0.7‰) in 2003 and 19.9‰ (SD = 0.7‰) in 2004. Mixing models indicated bowhead whales composed 11%–26% (95% CI) of the diets of sampled polar bears in 2003, and 0%–14% (95% CI) in 2004. This suggests significant variability in the proportion of lower trophic level prey in polar bear diets among individuals and between years. Polar bears depend on sea ice for hunting seals, and the temporal and spatial availabilities of sea ice are projected to decline. Consumption of low trophic level foods documented here suggests bears may increasingly scavenge such foods in the future.

Deciphering The Fall And Rise Of The Dead Sea In Relation To Solar Forcing

NASA Astrophysics Data System (ADS)

Yousef, Shahinaz M.

2005-03-01

Solar Forcing on closed seas and Lakes is space time dependent. The Cipher of the Dead Sea level variation since 1200 BC is solved in the context of millenium and Wolf-Gleissberg solar cycles time scales. It is found that the pattern of Dead Sea level variation follows the pattern of major millenium solar cycles. The 70 m rise of Dead Sea around 1AD is due to the forcing of the maximum millenium major solar cycle. Although the pattern of the Dead Sea level variation is almost identical to major solar cycles pattern between 1100 and 1980 AD, there is a dating problem of the Dead Sea time series around 1100-1300 AD that time. A discrepancy that should be corrected for the solar and Dead Sea series to fit. Detailed level variations of the Dead Sea level for the past 200 years are solved in terms of the 80-120 years solar Wolf-Gliessberg magnetic cycles. Solar induced climate changes do happen at the turning points of those cycles. Those end-start and maximum turning points are coincident with the change in the solar rotation rate due to the presence of weak solar cycles. Such weak cycles occur in series of few cycles between the end and start of those Wolf-Gleissberg cycles. Another one or two weak r solar cycle occur following the maximum of those Wolf-Gleissberg cycles. Weak cycles induce drop in the energy budget emitted from the sun and reaching the Earth thus causing solar induced climate change. An 8 meter sudden rise of Dead Sea occur prior 1900 AD due to positive solar forcing of the second cycle of the weak cycles series on the Dead Sea. The same second weak cycle induced negative solar forcing on Lake Chad. The first weak solar cycle forced Lake Victoria to rise abruptly in 1878. The maximum turning point of the solar Wolf-Gleissberg cycle induced negative forcing on both the Aral Sea and the Dead Sea causing their shrinkage to an alarming reduced area ever since. On the other hand, few years delayed positive forcing caused Lake Chad and the Equatorial African lakes to rise abruptly by several meters. Since the present solar cycle number 23 is the first weak cycle of a series, and since it caused 1.6 m sharp rise in Lake Victoria in 1997, then there is a high probability that the Dead Sea will rise by the beginning of the second weak cycle in few years time. And since both the Aral Sea and the Dead Sea are very much in coherence since the late 1950s, then it is rather likely that the Aral Sea will rise with God's wish in the near future. However it is also demanded that Israel should allow more water of the Jordan River to feed the Dead Sea before its real death. Plans for joining the Dead sea to the Red and or to the Mediterranean Seas should be cancelled owing the damaging harm it will cause the Dead Sea as a perfect indicator of solar induced climate change on one hand. On the other hand, the Dead Sea time series always show abrupt changes that can be as high as 70 m; if we add to this a planned artificial rise of the Dead Sea to its level of the thirties, then a damaging flooding effect will ruin the establishments and environment greatly.

Incorporating climate change and morphological uncertainty into coastal change hazard assessments

USGS Publications Warehouse

Baron, Heather M.; Ruggiero, Peter; Wood, Nathan J.; Harris, Erica L.; Allan, Jonathan; Komar, Paul D.; Corcoran, Patrick

2015-01-01

Documented and forecasted trends in rising sea levels and changes in storminess patterns have the potential to increase the frequency, magnitude, and spatial extent of coastal change hazards. To develop realistic adaptation strategies, coastal planners need information about coastal change hazards that recognizes the dynamic temporal and spatial scales of beach morphology, the climate controls on coastal change hazards, and the uncertainties surrounding the drivers and impacts of climate change. We present a probabilistic approach for quantifying and mapping coastal change hazards that incorporates the uncertainty associated with both climate change and morphological variability. To demonstrate the approach, coastal change hazard zones of arbitrary confidence levels are developed for the Tillamook County (State of Oregon, USA) coastline using a suite of simple models and a range of possible climate futures related to wave climate, sea-level rise projections, and the frequency of major El Niño events. Extreme total water levels are more influenced by wave height variability, whereas the magnitude of erosion is more influenced by sea-level rise scenarios. Morphological variability has a stronger influence on the width of coastal hazard zones than the uncertainty associated with the range of climate change scenarios.

Devastating tsunami inspires efforts to reduce future tsunami destruction

USGS Publications Warehouse

Lockridge, P.A.

1987-01-01

The beacon from landmark Scotch Cap lighthouse pierced the moonless night of April 1, 1946, in Alaska's remote Aleutain Island chain. In the reinforced concrete lighthouse, five men were engaged in various support operations connected with the maintenance of the 80,000 candlepower beam. Perched atop a building constructed 5 years earlier on a bluff 32 feet above sea level, the proud new light rose a total of 92 feet above the swirling restless seas. On a cliff behind the lighthouse, a second building housed the Coast Guard radio-direction-finding station. 

Cascading Effects of Ocean Acidification in a Rocky Subtidal Community

PubMed Central

Asnaghi, Valentina; Chiantore, Mariachiara; Mangialajo, Luisa; Gazeau, Frédéric; Francour, Patrice; Alliouane, Samir; Gattuso, Jean-Pierre

2013-01-01

Temperate marine rocky habitats may be alternatively characterized by well vegetated macroalgal assemblages or barren grounds, as a consequence of direct and indirect human impacts (e.g. overfishing) and grazing pressure by herbivorous organisms. In future scenarios of ocean acidification, calcifying organisms are expected to be less competitive: among these two key elements of the rocky subtidal food web, coralline algae and sea urchins. In order to highlight how the effects of increased pCO2 on individual calcifying species will be exacerbated by interactions with other trophic levels, we performed an experiment simultaneously testing ocean acidification effects on primary producers (calcifying and non-calcifying algae) and their grazers (sea urchins). Artificial communities, composed by juveniles of the sea urchin Paracentrotus lividus and calcifying (Corallina elongata) and non-calcifying (Cystoseira amentacea var stricta, Dictyota dichotoma) macroalgae, were subjected to pCO2 levels of 390, 550, 750 and 1000 µatm in the laboratory. Our study highlighted a direct pCO2 effect on coralline algae and on sea urchin defense from predation (test robustness). There was no direct effect on the non-calcifying macroalgae. More interestingly, we highlighted diet-mediated effects on test robustness and on the Aristotle's lantern size. In a future scenario of ocean acidification a decrease of sea urchins' density is expected, due to lower defense from predation, as a direct consequence of pH decrease, and to a reduced availability of calcifying macroalgae, important component of urchins' diet. The effects of ocean acidification may therefore be contrasting on well vegetated macroalgal assemblages and barren grounds: in the absence of other human impacts, a decrease of biodiversity can be predicted in vegetated macroalgal assemblages, whereas a lower density of sea urchin could help the recovery of shallow subtidal rocky areas affected by overfishing from barren grounds to assemblages dominated by fleshy macroalgae. PMID:23613994

Cascading effects of ocean acidification in a rocky subtidal community.

PubMed

Asnaghi, Valentina; Chiantore, Mariachiara; Mangialajo, Luisa; Gazeau, Frédéric; Francour, Patrice; Alliouane, Samir; Gattuso, Jean-Pierre

2013-01-01

Temperate marine rocky habitats may be alternatively characterized by well vegetated macroalgal assemblages or barren grounds, as a consequence of direct and indirect human impacts (e.g. overfishing) and grazing pressure by herbivorous organisms. In future scenarios of ocean acidification, calcifying organisms are expected to be less competitive: among these two key elements of the rocky subtidal food web, coralline algae and sea urchins. In order to highlight how the effects of increased pCO2 on individual calcifying species will be exacerbated by interactions with other trophic levels, we performed an experiment simultaneously testing ocean acidification effects on primary producers (calcifying and non-calcifying algae) and their grazers (sea urchins). Artificial communities, composed by juveniles of the sea urchin Paracentrotus lividus and calcifying (Corallina elongata) and non-calcifying (Cystoseira amentacea var stricta, Dictyota dichotoma) macroalgae, were subjected to pCO2 levels of 390, 550, 750 and 1000 µatm in the laboratory. Our study highlighted a direct pCO2 effect on coralline algae and on sea urchin defense from predation (test robustness). There was no direct effect on the non-calcifying macroalgae. More interestingly, we highlighted diet-mediated effects on test robustness and on the Aristotle's lantern size. In a future scenario of ocean acidification a decrease of sea urchins' density is expected, due to lower defense from predation, as a direct consequence of pH decrease, and to a reduced availability of calcifying macroalgae, important component of urchins' diet. The effects of ocean acidification may therefore be contrasting on well vegetated macroalgal assemblages and barren grounds: in the absence of other human impacts, a decrease of biodiversity can be predicted in vegetated macroalgal assemblages, whereas a lower density of sea urchin could help the recovery of shallow subtidal rocky areas affected by overfishing from barren grounds to assemblages dominated by fleshy macroalgae.

Dating glacimarine sediments from the continental shelf in the Amundsen Sea using a multi-tool box: Implications for West Antarctic ice-sheet extent and retreat during the last glacial cycle

NASA Astrophysics Data System (ADS)

Hillenbrand, C. D.; Smith, J.; Klages, J. P.; Kuhn, G.; Maher, B.; Moreton, S.; Wacker, L.; Frederichs, T.; Wiers, S.; Jernas, P.; Anderson, J. B.; Ehrmann, W. U.; Graham, A. G. C.; Gohl, K.; Larter, R. D.

2016-02-01

Satellite data and in-situ measurements show that today considerable mass loss is occurring from the Amundsen Sea sector of the West Antarctic Ice Sheet (WAIS). The observational record only spans the past four decades, and until recently the long-term context of the current deglaciation was poorly constrained. This information is, however, crucial for understanding WAIS dynamics, evaluating the role of forcing mechanisms for ice-sheet melting, and testing and calibrating ice-sheet models that attempt to predict future WAIS behavior and its impact on global sea level. Over the past decade several multinational marine expeditions and terrestrial fieldwork campaigns have targeted the Amundsen Sea shelf and its hinterland to reconstruct the WAIS configuration during the Last Glacial Maximum (LGM) and its subsequent deglacial history. The resulting studies succeeded in shedding light on the maximum WAIS extent at the LGM and the style, pattern and speed of its retreat and thinning thereafter. Despite this progress, however, significant uncertainties and discrepancies between marine and terrestrial reconstructions remain, which may arise from difficulties in dating sediment cores from the Antarctic shelf, especially their deglacial sections. Resolving these issues is crucial for understanding the WAIS' contribution to post-LGM sea-level rise, its sensitivity to different forcing mechanisms and its future evolution. Here we present chronological constraints on WAIS advance in the Amundsen Sea and its retreat from 20 ka BP into the Holocene that were obtained by various techniques, such as 14C dating of large ( 10 mg) and small (<<1 mg) sample aliquots of calcareous microfossils, 14C dating of acid-insoluble organic matter combusted at low (300 °C) and high (800 °C) temperatures and dating of sediment cores by using geomagnetic paleointensity. We will compare the different age constraints and discuss their reliability, applicability and implications for WAIS history.

Reconciling projections of the Antarctic contribution to sea level rise

NASA Astrophysics Data System (ADS)

Edwards, Tamsin; Holden, Philip; Edwards, Neil; Wernecke, Andreas

2017-04-01

Two recent studies of the Antarctic contribution to sea level rise this century had best estimates that differed by an order of magnitude (around 10 cm and 1 m by 2100). The first, Ritz et al. (2015), used a model calibrated with satellite data, giving a 5% probability of exceeding 30cm by 2100 for sea level rise due to Antarctic instability. The second, DeConto and Pollard (2016), used a model evaluated with reconstructions of palaeo-sea level. They did not estimate probabilities, but using a simple assumption here about the distribution shape gives up to a 5% chance of Antarctic contribution exceeding 2.3 m this century with total sea level rise approaching 3 m. If robust, this would have very substantial implications for global adaptation to climate change. How are we to make sense of this apparent inconsistency? How much is down to the data - does the past tell us we will face widespread and rapid Antarctic ice losses in the future? How much is due to the mechanism of rapid ice loss ('cliff failure') proposed in the latter paper, or other parameterisation choices in these low resolution models (GRISLI and PISM, respectively)? How much is due to choices made in the ensemble design and calibration? How do these projections compare with high resolution, grounding line resolving models such as BISICLES? Could we reduce the huge uncertainties in the palaeo-study? Emulation provides a powerful tool for understanding these questions and reconciling the projections. By describing the three numerical ice sheet models with statistical models, we can re-analyse the ensembles and re-do the calibrations under a common statistical framework. This reduces uncertainty in the PISM study because it allows massive sampling of the parameter space, which reduces the sensitivity to reconstructed palaeo-sea level values and also narrows the probability intervals because the simple assumption about distribution shape above is no longer needed. We present reconciled probabilistic projections for the Antarctic contribution to sea level rise from GRISLI, PISM and BISICLES this century, giving results that are meaningful and interpretable by decision-makers.

Sea-level rise along the Emilia-Romagna coast (Northern Italy) in 2100: scenarios and impacts

NASA Astrophysics Data System (ADS)

Perini, Luisa; Calabrese, Lorenzo; Luciani, Paolo; Olivieri, Marco; Galassi, Gaia; Spada, Giorgio

2017-12-01

As a consequence of climate change and land subsidence, coastal zones are directly impacted by sea-level rise. In some particular areas, the effects on the ecosystem and urbanisation are particularly enhanced. We focus on the Emilia-Romagna (E-R) coastal plain in Northern Italy, bounded by the Po river mouth to the north and by the Apennines to the south. The plain is ˜ 130 km long and is characterised by wide areas below mean sea level, in part made up of reclaimed wetlands. In this context, several morphodynamic factors make the shore and back shore unstable. During next decades, the combined effects of land subsidence and of the sea-level rise as a result of climate change are expected to enhance the shoreline instability, leading to further retreat. The consequent loss of beaches would impact the economy of the region, which is tightly connected with tourism infrastructures. Furthermore, the loss of wetlands and dunes would threaten the ecosystem, which is crucial for the preservation of life and the environment. These specific conditions show the importance of a precise definition of the possible local impacts of the ongoing and future climate variations. The aim of this work is the characterisation of vulnerability in different sectors of the coastal plain and the recognition of the areas in which human intervention is urgently required. The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) sea-level scenarios are merged with new high-resolution terrain models, current data for local subsidence and predictions of the flooding model in_CoastFlood in order to develop different scenarios for the impact of sea-level rise projected to year 2100. First, the potential land loss due to the combined effect of subsidence and sea-level rise is extrapolated. Second, the increase in floodable areas as a result of storm surges is quantitatively determined. The results are expected to support the regional mitigation and adaptation strategies designed in response to climate change.

Impacts of Multiple Stressors on Southern New England Salt Marshes

EPA Science Inventory

In the Northeastern U.S., salt marsh area is in decline. Low sediment supply combined with regionally high rates of sea level rise mean that future salt marsh survival depends primarily on biomass production and organic matter accumulation, which are impacted by high nutrient lo...

(Pre-) calibration of a Reduced Complexity Model of the Antarctic Contribution to Sea-level Changes

NASA Astrophysics Data System (ADS)

Ruckert, K. L.; Guan, Y.; Shaffer, G.; Forest, C. E.; Keller, K.

2015-12-01

(Pre-) calibration of a Reduced Complexity Model of the Antarctic Contribution to Sea-level ChangesKelsey L. Ruckert1*, Yawen Guan2, Chris E. Forest1,3,7, Gary Shaffer 4,5,6, and Klaus Keller1,7,81 Department of Geosciences, The Pennsylvania State University, University Park, Pennsylvania, USA 2 Department of Statistics, The Pennsylvania State University, University Park, Pennsylvania, USA 3 Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania, USA 4 GAIA_Antarctica, University of Magallanes, Punta Arenas, Chile 5 Center for Advanced Studies in Arid Zones, La Serena, Chile 6 Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark 7 Earth and Environmental Systems Institute, The Pennsylvania State University, University Park, Pennsylvania, USA 8 Department of Engineering and Public Policy, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA * Corresponding author. E-mail klr324@psu.eduUnderstanding and projecting future sea-level changes poses nontrivial challenges. Sea-level changes are driven primarily by changes in the density of seawater as well as changes in the size of glaciers and ice sheets. Previous studies have demonstrated that a key source of uncertainties surrounding sea-level projections is the response of the Antarctic ice sheet to warming temperatures. Here we calibrate a previously published and relatively simple model of the Antarctic ice sheet over a hindcast period from the last interglacial period to the present. We apply and compare a range of (pre-) calibration methods, including a Bayesian approach that accounts for heteroskedasticity. We compare the model hindcasts and projections for different levels of model complexity and calibration methods. We compare the projections with the upper bounds from previous studies and find our projections have a narrower range in 2100. Furthermore we discuss the implications for the design of climate risk management strategies.

Impacts of the north and tropical Atlantic Ocean on the Antarctic Peninsula and sea ice.

PubMed

Li, Xichen; Holland, David M; Gerber, Edwin P; Yoo, Changhyun

2014-01-23

In recent decades, Antarctica has experienced pronounced climate changes. The Antarctic Peninsula exhibited the strongest warming of any region on the planet, causing rapid changes in land ice. Additionally, in contrast to the sea-ice decline over the Arctic, Antarctic sea ice has not declined, but has instead undergone a perplexing redistribution. Antarctic climate is influenced by, among other factors, changes in radiative forcing and remote Pacific climate variability, but none explains the observed Antarctic Peninsula warming or the sea-ice redistribution in austral winter. However, in the north and tropical Atlantic Ocean, the Atlantic Multidecadal Oscillation (a leading mode of sea surface temperature variability) has been overlooked in this context. Here we show that sea surface warming related to the Atlantic Multidecadal Oscillation reduces the surface pressure in the Amundsen Sea and contributes to the observed dipole-like sea-ice redistribution between the Ross and Amundsen-Bellingshausen-Weddell seas and to the Antarctic Peninsula warming. Support for these findings comes from analysis of observational and reanalysis data, and independently from both comprehensive and idealized atmospheric model simulations. We suggest that the north and tropical Atlantic is important for projections of future climate change in Antarctica, and has the potential to affect the global thermohaline circulation and sea-level change.

Cloud Response to Arctic Sea Ice Loss and Implications for Feedbacks in the CESM1 Climate Model

NASA Astrophysics Data System (ADS)

Morrison, A.; Kay, J. E.; Chepfer, H.; Guzman, R.; Bonazzola, M.

2017-12-01

Clouds have the potential to accelerate or slow the rate of Arctic sea ice loss through their radiative influence on the surface. Cloud feedbacks can therefore play into Arctic warming as clouds respond to changes in sea ice cover. As the Arctic moves toward an ice-free state, understanding how cloud - sea ice relationships change in response to sea ice loss is critical for predicting the future climate trajectory. From satellite observations we know the effect of present-day sea ice cover on clouds, but how will clouds respond to sea ice loss as the Arctic transitions to a seasonally open water state? In this study we use a lidar simulator to first evaluate cloud - sea ice relationships in the Community Earth System Model (CESM1) against present-day observations (2006-2015). In the current climate, the cloud response to sea ice is well-represented in CESM1: we see no summer cloud response to changes in sea ice cover, but more fall clouds over open water than over sea ice. Since CESM1 is credible for the current Arctic climate, we next assess if our process-based understanding of Arctic cloud feedbacks related to sea ice loss is relevant for understanding future Arctic clouds. In the future Arctic, summer cloud structure continues to be insensitive to surface conditions. As the Arctic warms in the fall, however, the boundary layer deepens and cloud fraction increases over open ocean during each consecutive decade from 2020 - 2100. This study will also explore seasonal changes in cloud properties such as opacity and liquid water path. Results thus far suggest that a positive fall cloud - sea ice feedback exists in the present-day and future Arctic climate.

Trends in the components of extreme water levels signal a rotation of winds in strong storms in the eastern Baltic Sea

NASA Astrophysics Data System (ADS)

Pindsoo, Katri; Soomere, Tarmo

2016-04-01

The water level time series and particularly temporal variations in water level extremes usually do not follow any simple rule. Still, the analysis of linear trends in extreme values of surge levels is a convenient tool to obtain a first approximation of the future projections of the risks associated with coastal floodings. We demonstrate how this tool can be used to extract essential information about concealed changes in the forcing factors of seas and oceans. A specific feature of the Baltic Sea is that sequences of even moderate storms may raise the average sea level by almost 1 m for a few weeks. Such events occur once in a few years. They substantially contribute to the extreme water levels in the eastern Baltic Sea: the most devastating coastal floodings occur when a strong storm from unfortunate direction arrives during such an event. We focus on the separation of subtidal (weekly-scale) processes from those which are caused by a single storm and on establishing how much these two kinds of events have contributed to the increase in the extreme water levels in the eastern Baltic Sea. The analysis relies on numerically reconstructed sea levels produced by the RCO (Rossby Center, Swedish Meteorological and Hydrological Institute) ocean model for 1961-2005. The reaction of sea surface to single storm events is isolated from the local water level time series using a running average over a fixed interval. The distribution of average water levels has an almost Gaussian shape for averaging lengths from a few days to a few months. The residual (total water level minus the average) can be interpreted as a proxy of the local storm surges. Interestingly, for the 8-day average this residual almost exactly follows the exponential distribution. Therefore, for this averaging length the heights of local storm surges reflect an underlying Poisson process. This feature is universal for the entire eastern Baltic Sea coast. The slopes of the exponential distribution for low and high water levels are different, vary markedly along the coast and provide a useful quantification of the vulnerability of single coastal segments with respect to coastal flooding. The formal linear trends in the extreme values of these water level components exhibit radically different spatial variations. The slopes of the trends in the weekly average are almost constant (~4 cm/decade for 8-day running average) along the entire eastern Baltic Sea coast. This first of all indicates that the duration of storm sequences has increased. The trends for maxima of local storm surge heights represent almost the entire spatial variability in the water level extremes. Their slopes are almost zero at the open Baltic Proper coasts of the Western Estonian archipelago. Therefore, an increase in wind speed in strong storms is unlikely in this area. In contrast, the slopes in question reach 5-7 cm/decade in the eastern Gulf of Finland and Gulf of Riga. This feature suggests that wind direction in strongest storms may have rotated in the northern Baltic Sea.

Coupled Long-Term Evolution of Climate and the Greenland Ice Sheet During the Last Interglacial and Implications for the Future

NASA Astrophysics Data System (ADS)

Otto-Bliesner, B. L.; Lofverstrom, M.; Lipscomb, W.; Fyke, J. G.; Marshall, S.; Sacks, B.

2017-12-01

The Greenland Ice Sheet (GrIS) is expected to contribute increasingly to global sea level rise by the end of this century, and potentially several meters in this millennium, but still with considerable uncertainty. The rate of Greenland melt will impact on regional sea levels. The Last Interglacial (LIG, 129 ka to 116 ka) is recognized as an important period for testing our knowledge of climate-ice sheet interactions in warm climate states. Although the LIG was discussed in the First Assessment Report of the IPCC, it gained more prominence in the IPCC Fourth and Fifth Assessment (AR4 and AR5) with reconstructions highlighting that global mean sea level was at least 5 m higher (but probably no more than 10 m higher) than present for several thousand years during the LIG. Model results assessed for the AR5 suggest a sea level contribution of 1.4 to 4.3 m from the GrIS. These model simulations, though, did not include all the feedbacks of the climate system and the GrIS. Here, we examine the response of the Arctic climate system and the GrIS in simulations with the Community Earth System Model (CESM) fully coupled to the Community Ice Sheet Model (CISM), using a surface energy balance scheme and without bias corrections. The analysis focuses on how the GrIS responds to the imposed high boreal summer insolation of the LIG and in addition, to the long-term feedbacks of high-latitude vegetation changes. Results will highlight the evolution of the ice sheet and the surface mass balance (patterns of ablation and accumulation) as compared to data-based reconstructions for the LIG. We conclude with a discussion on how the LIG may be informative as a potential process analogue for the GrIS response for future centuries to come.

Constraining the Antarctic contribution to global sea-level change: ANDRILL and beyond

NASA Astrophysics Data System (ADS)

Naish, Timothy

2016-04-01

Observations, models and paleoclimate reconstructions suggest that Antarctica's marine-based ice sheets behave in an unstable manner with episodes of rapid retreat in response to warming climate. Understanding the processes involved in this "marine ice sheet instability" is key for improving estimates of Antarctic ice sheet contribution to future sea-level rise. Another motivating factor is that far-field sea-level reconstructions and ice sheet models imply global mean sea level (GMSL) was up to 20m and 10m higher, respectively, compared with present day, during the interglacials of the warm Pliocene (~4-3Ma) and Late Pleistocene (at ~400ka and 125ka). This was when atmospheric CO2 was between 280 and 400ppm and global average surface temperatures were 1 to 3°C warmer, suggesting polar ice sheets are highly sensitive to relatively modest increases in climate forcing. Such magnitudes of GMSL rise not only require near complete melt of the Greenland Ice Sheet and the West Antarctic Ice Sheet, but a substantial retreat of marine-based sectors of East Antarctic Ice Sheet. Recent geological drilling initiatives on the continental margin of Antarctica from both ship- (e.g. IODP; International Ocean Discovery Program) and ice-based (e.g. ANDRILL/Antarctic Geological Drilling) platforms have provided evidence supporting retreat of marine-based ice. However, without direct access through the ice sheet to archives preserved within sub-glacial sedimentary basins, the volume and extent of ice sheet retreat during past interglacials cannot be directly constrained. Sediment cores have been successfully recovered from beneath ice shelves by the ANDRILL Program and ice streams by the WISSARD (Whillans Ice Stream Sub-glacial Access Research Drilling) Project. Together with the potential of the new RAID (Rapid Access Ice Drill) initiative, these demonstrate the technological feasibility of accessing the subglacial bed and deeper sedimentary archives. In this talk I will outline the scientific challenges, some potential sub-glacial sedimentary targets, and a strategy for future drilling of sub-glacial sedimentary basins.

Constraining the Antarctic contribution to interglacial sea-level rise

NASA Astrophysics Data System (ADS)

Naish, T.; Mckay, R. M.; Barrett, P. J.; Levy, R. H.; Golledge, N. R.; Deconto, R. M.; Horgan, H. J.; Dunbar, G. B.

2015-12-01

Observations, models and paleoclimate reconstructions suggest that Antarctica's marine-based ice sheets behave in an unstable manner with episodes of rapid retreat in response to warming climate. Understanding the processes involved in this "marine ice sheet instability" is key for improving estimates of Antarctic ice sheet contribution to future sea-level rise. Another motivating factor is that far-field sea-level reconstructions and ice sheet models imply global mean sea level (GMSL) was up to 20m and 10m higher, respectively, compared with present day, during the interglacials of the warm Pliocene (~4-3Ma) and Late Pleistocene (at ~400ka and 125ka). This was when atmospheric CO2 was between 280 and 400ppm and global average surface temperatures were 1- 3°C warmer, suggesting polar ice sheets are highly sensitive to relatively modest increases in climate forcing. Such magnitudes of GMSL rise not only require near complete melt of the Greenland Ice Sheet and the West Antarctic Ice Sheet, but a substantial retreat of marine-based sectors of East Antarctic Ice Sheet. Recent geological drilling initiatives on the continental margin of Antarctica from both ship- (e.g. IODP; International Ocean Discovery Program) and ice-based (e.g. ANDRILL/Antarctic Geological Drilling) platforms have provided evidence supporting retreat of marine-based ice. However, without direct access through the ice sheet to archives preserved within sub-glacial sedimentary basins, the volume and extent of ice sheet retreat during past interglacials cannot be directly constrained. Sediment cores have been successfully recovered from beneath ice shelves by the ANDRILL Program and ice streams by the WISSARD (Whillans Ice Stream Sub-glacial Access Research Drilling) Project. Together with the potential of the new RAID (Rapid Access Ice Drill) initiative, these demonstrate the technological feasibility of accessing the subglacial bed and deeper sedimentary archives. In this talk I will outline the scientific challenges, some potential sub-glacial sedimentary targets, and a strategy for future drilling of sub-glacial sedimentary basins.

Remote sensing and GIS analysis for demarcation of coastal hazard line along the highly eroding Krishna-Godavari delta front

NASA Astrophysics Data System (ADS)

Kallepalli, Akhil; Kakani, Nageswara Rao; James, David B.

2016-10-01

Coastal regions, especially river deltas are highly resourceful and hence densely populated; but these extremely low-lying lands are vulnerable to rising sea levels due to global warming threatening the life and property in these regions. Recent IPCC (2013) predictions of 26-82cm global sea level rise are now considered conservative as subsequent investigations such as by Met Office, UK indicated a vertical rise of about 190cm, which would displace 10% of the world's population living within 10 meters above the sea level. Therefore, predictive models showing the hazard line are necessary for efficient coastal zone management. Remote sensing and GIS technologies form the mainstay of such predictive models on coastal retreat and inundation to future sea-level rise. This study is an attempt to estimate the varying trends along the Krishna-Godavari (K-G) delta region. Detailed maps showing various coastal landforms in the K-G delta region were prepared using the IRS-P6 LISS 3 images. The rate of shoreline shift during a 31-year period along different sectors of the 330km long K-G delta coast was estimated using Landsat-2 and IRS-P6 LISS 3 images between 1977 and 2008. With reference to a selected baseline from along an inland position, End Point Rate (EPR), Shoreline Change Envelope (SCE) and Net Shoreline Movement (NSM) were calculated, using a GIS-based Digital Shoreline Analysis System (DSAS). The results showed that the shoreline migrated landward up to a maximum distance of 3.13km resulting in a net loss of about 42.10km2 area during this 31-year period. Further, considering the nature of landforms and EPR, the future hazard line is predicted for the area, which also indicated a net erosion of about 57.68km2 along the K-G delta coast by 2050 AD.

Greenland ice-sheet contribution to sea-level rise buffered by meltwater storage in firn.

PubMed

Harper, J; Humphrey, N; Pfeffer, W T; Brown, J; Fettweis, X

2012-11-08

Surface melt on the Greenland ice sheet has shown increasing trends in areal extent and duration since the beginning of the satellite era. Records for melt were broken in 2005, 2007, 2010 and 2012. Much of the increased surface melt is occurring in the percolation zone, a region of the accumulation area that is perennially covered by snow and firn (partly compacted snow). The fate of melt water in the percolation zone is poorly constrained: some may travel away from its point of origin and eventually influence the ice sheet's flow dynamics and mass balance and the global sea level, whereas some may simply infiltrate into cold snow or firn and refreeze with none of these effects. Here we quantify the existing water storage capacity of the percolation zone of the Greenland ice sheet and show the potential for hundreds of gigatonnes of meltwater storage. We collected in situ observations of firn structure and meltwater retention along a roughly 85-kilometre-long transect of the melting accumulation area. Our data show that repeated infiltration events in which melt water penetrates deeply (more than 10 metres) eventually fill all pore space with water. As future surface melt intensifies under Arctic warming, a fraction of melt water that would otherwise contribute to sea-level rise will fill existing pore space of the percolation zone. We estimate the lower and upper bounds of this storage sink to be 322 ± 44 gigatonnes and  1,289(+388)(-252) gigatonnes, respectively. Furthermore, we find that decades are required to fill this pore space under a range of plausible future climate conditions. Hence, routing of surface melt water into filling the pore space of the firn column will delay expansion of the area contributing to sea-level rise, although once the pore space is filled it cannot quickly be regenerated.

Sea level rise under the Shared Socioeconomic Pathways (SSPs)

NASA Astrophysics Data System (ADS)

Schleussner, C. F.; Nauels, A.; Rogelj, J.; Mengel, M.; Meinshausen, M.

2017-12-01

In order to assess future sea level rise and its impacts, we need to study climate change pathways combined with different scenarios of socioeconomic development. Here, we present Sea Level Rise (SLR) projections for the Shared Socioeconomic Pathway (SSP) storylines and different year-2100 radiative Forcing Targets (FTs). Future SLR is estimated with a comprehensive SLR emulator that accounts for latest research on additional Antarctic rapid discharge dynamics from hydrofracturing and ice cliff instability. Across all baseline scenario realizations (no dedicated climate mitigation), we find 2100 median SLR relative to 1986-2005 of 102 cm (likely range: 77 to 135 cm) for SSP1, 118 cm (90 to 151 cm) for SSP2, 118 cm (91 to 149 cm) for SSP3, 107 cm (81 to 137 cm) for SSP4, and 144 cm (112 to 184 cm) for SSP5. The 2100 sea level responses for combined SSP-FT scenarios is dominated by the mitigation targets and yield median estimates of 68 cm (56 to 87 cm) for FT 2.6 Wm-2, 76 cm (61 to 107 cm) for FT 3.4 Wm-2, 90 cm (68 to 120 cm) for FT 4.5 Wm-2, and 105 cm (79 to 136 cm) for FT 6.0 Wm-2. Average 2081-2100 annual rates of SLR are 6 mm/yr and 19 mm/yr for the FT 2.6 Wm-2 and the baseline scenarios, respectively. Our model setup allows linking scenario-specific emission and socioeconomic indicators to projected SLR. For limiting median 2100 SSP SLR projections to below 80 cm, we find that 2050 cumulative CO2 emissions since pre-industrial should not exceed around 860 GtC, with the global coal phase-out nearly completed. For SSP mitigation scenarios, the median 2050 carbon price of 90 US$2005 tCO2-1 would correspond to a median 2100 SLR of around 80 cm. Our results confirm that rapid and early emission reductions are essential for limiting 2100 SLR.

Current Status and Future Plan of Arctic Sea Ice monitoring in South Korea

NASA Astrophysics Data System (ADS)

Shin, J.; Park, J.

2016-12-01

Arctic sea ice is one of the most important parameters in climate. For monitoring of sea ice changes, the National Meteorological Satellite Center (NMSC) of Korea Metrological Administration has developed the "Arctic sea ice monitoring system" to retrieve the sea ice extent and surface roughness using microwave sensor data, and statistical prediction model for Arctic sea ice extent. This system has been implemented to the web site for real-time public service. The sea ice information can be retrieved using the spaceborne microwave sensor-Special Sensor Microwave Imager/Sounder (SSMI/S). The sea ice information like sea ice extent, sea ice surface roughness, and predictive sea ice extent are produced weekly base since 2007. We also publish the "Analysis report of the Arctic sea ice" twice a year. We are trying to add more sea ice information into this system. Details of current status and future plan of Arctic sea ice monitoring and the methodology of the sea ice information retrievals will be presented in the meeting.

Benchmarking and testing the "Sea Level Equation

NASA Astrophysics Data System (ADS)

Spada, G.; Barletta, V. R.; Klemann, V.; van der Wal, W.; James, T. S.; Simon, K.; Riva, R. E. M.; Martinec, Z.; Gasperini, P.; Lund, B.; Wolf, D.; Vermeersen, L. L. A.; King, M. A.

2012-04-01

The study of the process of Glacial Isostatic Adjustment (GIA) and of the consequent sea level variations is gaining an increasingly important role within the geophysical community. Understanding the response of the Earth to the waxing and waning ice sheets is crucial in various contexts, ranging from the interpretation of modern satellite geodetic measurements to the projections of future sea level trends in response to climate change. All the processes accompanying GIA can be described solving the so-called Sea Level Equation (SLE), an integral equation that accounts for the interactions between the ice sheets, the solid Earth, and the oceans. Modern approaches to the SLE are based on various techniques that range from purely analytical formulations to fully numerical methods. Despite various teams independently investigating GIA, we do not have a suitably large set of agreed numerical results through which the methods may be validated. Following the example of the mantle convection community and our recent successful Benchmark for Post Glacial Rebound codes (Spada et al., 2011, doi: 10.1111/j.1365-246X.2011.04952.x), here we present the results of a benchmark study of independently developed codes designed to solve the SLE. This study has taken place within a collaboration facilitated through the European Cooperation in Science and Technology (COST) Action ES0701. The tests involve predictions of past and current sea level variations, and 3D deformations of the Earth surface. In spite of the signi?cant differences in the numerical methods employed, the test computations performed so far show a satisfactory agreement between the results provided by the participants. The differences found, which can be often attributed to the different numerical algorithms employed within the community, help to constrain the intrinsic errors in model predictions. These are of fundamental importance for a correct interpretation of the geodetic variations observed today, and particularly for the evaluation of climate-driven sea level variations.

The changing seascape of Galway Bay, Western Ireland

NASA Astrophysics Data System (ADS)

Mc Cullagh, D.; Benetti, S.; Plets, R. M. K.; Edwards, R.

2016-12-01

During the late Quaternary significant environmental and relative sea-level variations have contributed to shaping present day coastlines. This is particularly evident along formerly glaciated continental margins. Strong evidence of these changes are recorded in Galway Bay, Western Ireland. This research uses a multidisciplinary approach. Seismic and multibeam data, sedimentological, micropaleontological, geochemical analysis and 15 radiocarbon dates of sediment cores from the bay provide post last glacial maximum (LGM) sea level and environmental reconstructions for the region. The acoustic stratigraphy of the bay includes 3 seismic units: the deepest unit represents the acoustic basement, composed of limestone and granite bedrock; the middle unit is composed of the oldest preserved sediments, deposited during and after the LGM, and interpreted to be glacial till. The uppermost unit represents deposition and reworking after glacial retreat. The erosive action of the ice sheet that extended off the Irish coast is thought to be responsible for the removal and reworking of all sediments older that the LGM. In the sediment cores, three main lithofacies were identified: 1) a sandy silt and clay facies, 2) a distinct shell hash interlayer and, 3) a fine silty sand facies. These 3 facies are found within the uppermost seismic unit, and initial radiocarbon dating of shells in 4 cores, constrain these sediments and the uppermost seismic unit to the Holocene. Preliminary qualitative analysis on foraminifera from several cores shows a general trend of progression from estuarine to open marine conditions, inferred from indicator species. This trend is supported by X-ray fluorescence (XRF) analysis which shows increased ratios of Cl/Fe in younger deposits. Constraining dates on sea level variations in the region will be added to the sea level database for Ireland and possibly used to adjust the existing relative sea level models. These are important for understating past sea level variations and modelling future trends.