Science.gov

Sample records for warm climatic conditions

  1. Assessment of permafrost conditions under Northern Quebec's airports: an integrative approach for the development of adaptation strategies to climate warming

    NASA Astrophysics Data System (ADS)

    L'Hérault, E.; Allard, M.; Doré, G.; Barrette, C.; Verreault, J.; Sarrazin, D.; Doyon, J.; Guimond, A.

    2011-12-01

    Community airports in Nunavik were built between 1984 and 1992 and were designed by using a thick embankment of rock fill placed on undisturbed ground surface to prevent the thawing of the underlying permafrost. However, since around 2000, many of the runways show signs of permafrost disturbance as some localized differential settlements have begun to take place. With the anticipated rise of air temperature, the vulnerability of transportation infrastructures to permafrost degradation raises concerns. Several studies initiated by MTQ were undertaken by CEN to evaluate the permafrost conditions underneath airports. These studies provide valuable baseline information but also reveal the needs for a better understanding of the spatial variability of the surficial deposits, their geotechnical properties and permafrost conditions underneath embankments to assess its sensibility to thawing and to plan adaptation strategies in face of climate warming. A geomorphological and geotechnical investigation campaign, including surficial geology mapping using pre-construction air photographs and recovery of drilled frozen cores, was carried out in the summers 2008 and 2009 at eight airports. The impact of the runway embankments on surface drainage, snow drift accumulation and permafrost thawing was also determined. Stratigraphic information from drilling was used to reinterpret CCR and GPR surveys done in previous studies. High resolution cross-sections of the stratigraphy and permafrost conditions could then be drawn. Lab testing over undisturbed frozen samples was performed to determine the geotechnical properties of the different stratigraphic units encountered, particularly thaw consolidation ratios. Field measurements of ground temperatures and numerical modeling of the thermal regime of the embankment and subgrade were also performed to assess the potential impacts on permafrost stability alongside and beneath embankments under different climate change scenarios. Thermistor readings show that the active layer in the central part of the runways is in most case still contained in the embankment or within the prior-to-construction consolidated active layer. However, a residual thaw layer (talik) is now present at the toe of embankments where significant snow accumulations occurred. Thermal modeling indicates that water accumulation and seepage as well as snow accumulation along embankment shoulders are currently the dominant factors of permafrost degradation. In the future, centerlines of embankment built on ice rich permafrost will gradually settle as the climate warms up; therefore periodic reloading will be necessary. To counter permafrost degradation alongside runways and access roads, the proposed mitigation strategies focus on minimizing snow and water accumulation by making gentler slopes (1:6) and by improving the drainage system to avoid potential seepage through embankments.

  2. The global climate of December 1992-February 1993. Part I: Warm ENSO conditions continue in the tropical Pacific; California drought abates

    SciTech Connect

    Bell, G.D.; Basist, A.N.

    1994-10-01

    Part I of this Seasonal Climate Summary present an analysis of the global climate during December 1992 - February 1993 (DJF). Atmospheric and oceanic indices indicate the redevelopment of mature El Nino-Southern Oscillation conditions in the tropical Pacific during DJF. This marks one of the longest periods of continuous warm episode conditions on record. Above normal sea surface temperature covered large portions of the tropical and subtropical eastern Pacific during the period. In the extratropics, one prominent feature during the season was extremely heavy precipitation totals over California and the southwestern US. This precipitation was associated with enhanced southwesterly flow, above normal cyclone activity, and enhanced transport of low-level moisture into the region from the subtropical North Pacific. A second prominent feature was a strong positive phase of the North Atlantic Oscillation.

  3. Climatic warming disrupts recurrent Alpine insect outbreaks

    E-print Network

    Liebhold, Andrew

    for diverse ecological changes worldwide. Warming trends over the last couple of decades have coincided such as with competitors and natural enemies (4, 5). Global warming has recently been implicated in elevational rangeClimatic warming disrupts recurrent Alpine insect outbreaks Derek M. Johnsona,1 , Ulf Büntgenb

  4. Soil degradation, global warming and climate impacts

    E-print Network

    Feddema, Johannes J.; Freire, Sergio Carneiro

    2001-01-01

    stream_size 21847 stream_content_type text/plain stream_name Feddema_Soil_Degradation_Global_Warming.pdf.txt stream_source_info Feddema_Soil_Degradation_Global_Warming.pdf.txt Content-Encoding UTF-8 Content-Type text.... This study will demonstrate one methodology for assessing the potential large-scale impacts of soil degradation on African climates and water resources. In addition it will compare and contrast these impacts to those expected from global warming and compare...

  5. Climatic warming disrupts recurrent Alpine insect outbreaks

    E-print Network

    Esper, Jan

    Climatic warming disrupts recurrent Alpine insect outbreaks Derek M. Johnsona,1 , Ulf Büntgenb shifts of plants (1, 6) and animals (7, 8) at various spatiotemporal scales (9). Range shifts are often scale warming trends have coincided with the collapse of population cycles across a broad range of taxa

  6. State-dependent climate sensitivity in past warm climates and its implications for future climate projections

    PubMed Central

    Caballero, Rodrigo; Huber, Matthew

    2013-01-01

    Projections of future climate depend critically on refined estimates of climate sensitivity. Recent progress in temperature proxies dramatically increases the magnitude of warming reconstructed from early Paleogene greenhouse climates and demands a close examination of the forcing and feedback mechanisms that maintained this warmth and the broad dynamic range that these paleoclimate records attest to. Here, we show that several complementary resolutions to these questions are possible in the context of model simulations using modern and early Paleogene configurations. We find that (i) changes in boundary conditions representative of slow “Earth system” feedbacks play an important role in maintaining elevated early Paleogene temperatures, (ii) radiative forcing by carbon dioxide deviates significantly from pure logarithmic behavior at concentrations relevant for simulation of the early Paleogene, and (iii) fast or “Charney” climate sensitivity in this model increases sharply as the climate warms. Thus, increased forcing and increased slow and fast sensitivity can all play a substantial role in maintaining early Paleogene warmth. This poses an equifinality problem: The same climate can be maintained by a different mix of these ingredients; however, at present, the mix cannot be constrained directly from climate proxy data. The implications of strongly state-dependent fast sensitivity reach far beyond the early Paleogene. The study of past warm climates may not narrow uncertainty in future climate projections in coming centuries because fast climate sensitivity may itself be state-dependent, but proxies and models are both consistent with significant increases in fast sensitivity with increasing temperature. PMID:23918397

  7. How strong is carbon cycle-climate feedback under global warming?

    E-print Network

    Maryland at College Park, University of

    How strong is carbon cycle-climate feedback under global warming? Haifeng Qian Advisor: Prof. Ning of the carbon cycle-climate system. Our results indicate that there is a positive feedback from interactive carbon cycle to the climate system, which means that under the global warming condition, the ecosystem

  8. Influence of free-stall flooring on comfort and hygiene of dairy cows during warm climatic conditions.

    PubMed

    De Palo, P; Tateo, A; Zezza, F; Corrente, M; Centoducati, P

    2006-12-01

    An evaluation of behavioral and hygienic conditions was carried out with 4 materials used as free-stall flooring for dairy cows: polyethylene vinyl acetate (EVA) and polypropylene vinyl acetate (PVA) mats, wood shavings, and solid manure. The free-stall type selected by cows was evaluated in response to changes in environmental temperature and humidity. Two tests were used: 1) a preference test, in which 8 cows were housed in a pen with 32 free stalls and 4 types of flooring; and 2) an aversion test, in which 32 cows were placed in 4 pens, each with 8 free stalls. The free stalls in each pen had a single type of bedding material. These tests showed that the comfort of dairy cows was predominantly influenced by environmental conditions. The preference test for lying showed that cows preferred free-stall floors with EVA mats over those with PVA mats, wood shavings, and solid manure (332.4 +/- 24.0 vs. 130.8 +/- 6.2, 160.9 +/- 23.7, and 102.6 +/- 23.2 min/d, respectively), but under conditions of heat stress, with a temperature-humidity index > 80, they chose wood shavings and solid manure lying areas. These results were confirmed by the aversion test. In all experimental and environmental conditions, the PVA mats were the least suitable. The mats contaminated with organic manure and the free stalls bedded with wood shavings and organic solids did not differ in either the coliform load on the lying surfaces (EVA mats: 290 +/- 25; PVA mats: 306 +/- 33; wood shavings: 290 +/- 39; and solid manure: 305 +/- 23 log(10) cfu/mL) or the total bacterial count in the raw milk (EVA mats: 232 +/- 22; PVA mats: 233 + 24; wood shavings: 221 +/- 24; and solid manure: 220 +/- 25 log(10) cfu/mL). These results demonstrate that the comfort of dairy cows housed in barns with free stalls as resting areas does not depend only on the material used, but also on the value of the material in microenvironmental conditions. PMID:17106090

  9. Effects of in situ climate warming on monarch caterpillar (Danaus plexippus) development

    PubMed Central

    Capdevielle, Jillian N.; Parker, John D.

    2015-01-01

    Climate warming will fundamentally alter basic life history strategies of many ectothermic insects. In the lab, rising temperatures increase growth rates of lepidopteran larvae but also reduce final pupal mass and increase mortality. Using in situ field warming experiments on their natural host plants, we assessed the impact of climate warming on development of monarch (Danaus plexippus) larvae. Monarchs were reared on Asclepias tuberosa grown under ‘Ambient’ and ‘Warmedconditions. We quantified time to pupation, final pupal mass, and survivorship. Warming significantly decreased time to pupation, such that an increase of 1 °C corresponded to a 0.5 day decrease in pupation time. In contrast, survivorship and pupal mass were not affected by warming. Our results indicate that climate warming will speed the developmental rate of monarchs, influencing their ecological and evolutionary dynamics. However, the effects of climate warming on larval development in other monarch populations and at different times of year should be investigated. PMID:26528403

  10. Projected changes of snow conditions and avalanche activity in a warming climate: the French Alps over the 2020-2050 and 2070-2100 periods

    NASA Astrophysics Data System (ADS)

    Castebrunet, H.; Eckert, N.; Giraud, G.; Durand, Y.; Morin, S.

    2014-09-01

    Projecting changes in snow cover due to climate warming is important for many societal issues, including the adaptation of avalanche risk mitigation strategies. Efficient modelling of future snow cover requires high resolution to properly resolve the topography. Here, we introduce results obtained through statistical downscaling techniques allowing simulations of future snowpack conditions including mechanical stability estimates for the mid and late 21st century in the French Alps under three climate change scenarios. Refined statistical descriptions of snowpack characteristics are provided in comparison to a 1960-1990 reference period, including latitudinal, altitudinal and seasonal gradients. These results are then used to feed a statistical model relating avalanche activity to snow and meteorological conditions, so as to produce the first projection on annual/seasonal timescales of future natural avalanche activity based on past observations. The resulting statistical indicators are fundamental for the mountain economy in terms of anticipation of changes. Whereas precipitation is expected to remain quite stationary, temperature increase interacting with topography will constrain the evolution of snow-related variables on all considered spatio-temporal scales and will, in particular, lead to a reduction of the dry snowpack and an increase of the wet snowpack. Overall, compared to the reference period, changes are strong for the end of the 21st century, but already significant for the mid century. Changes in winter are less important than in spring, but wet-snow conditions are projected to appear at high elevations earlier in the season. At the same altitude, the southern French Alps will not be significantly more affected than the northern French Alps, which means that the snowpack will be preserved for longer in the southern massifs which are higher on average. Regarding avalanche activity, a general decrease in mean (20-30%) and interannual variability is projected. These changes are relatively strong compared to changes in snow and meteorological variables. The decrease is amplified in spring and at low altitude. In contrast, an increase in avalanche activity is expected in winter at high altitude because of conditions favourable to wet-snow avalanches earlier in the season. Comparison with the outputs of the deterministic avalanche hazard model MEPRA (Modèle Expert d'aide à la Prévision du Risque d'Avalanche) shows generally consistent results but suggests that, even if the frequency of winters with high avalanche activity is clearly projected to decrease, the decreasing trend may be less strong and smooth than suggested by the statistical analysis based on changes in snowpack characteristics and their links to avalanches observations in the past. This important point for risk assessment pleads for further work focusing on shorter timescales. Finally, the small differences between different climate change scenarios show the robustness of the predicted avalanche activity changes.

  11. Hurricanes in a Warming Climate

    NASA Astrophysics Data System (ADS)

    Emanuel, K.

    2011-12-01

    We will review evidence that Atlantic hurricane activity has responded to both natural and anthropogenic climate change over the past century and explore the physical causes of the observed changes. We will argue that while basic theory suggests that the global frequency of events should decline, it is likely that the global trend will be small compared to trends in individual ocean basins; moreover, theory and observations consistently show that the intensity of the most intense events is increasing and should continue to do so. Finally, we present evidence that a major cause of the upswing in Atlantic hurricane activity over the past two decades has been the cooling of the tropical tropopause transition layer.

  12. Climate warming will not decrease winter mortality

    NASA Astrophysics Data System (ADS)

    Staddon, Philip L.; Montgomery, Hugh E.; Depledge, Michael H.

    2014-03-01

    It is widely assumed by policymakers and health professionals that the harmful health impacts of anthropogenic climate change will be partially offset by a decline in excess winter deaths (EWDs) in temperate countries, as winters warm. Recent UK government reports state that winter warming will decrease EWDs. Over the past few decades, however, the UK and other temperate countries have simultaneously experienced better housing, improved health care, higher incomes and greater awareness of the risks of cold. The link between winter temperatures and EWDs may therefore no longer be as strong as before. Here we report on the key drivers that underlie year-to-year variations in EWDs. We found that the association of year-to-year variation in EWDs with the number of cold days in winter ( <5 °C), evident until the mid 1970s, has disappeared, leaving only the incidence of influenza-like illnesses to explain any of the year-to-year variation in EWDs in the past decade. Although EWDs evidently do exist, winter cold severity no longer predicts the numbers affected. We conclude that no evidence exists that EWDs in England and Wales will fall if winters warm with climate change. These findings have important implications for climate change health adaptation policies.

  13. Evaluating the Dominant Components of Warming in Pliocene Climate Simulations

    NASA Technical Reports Server (NTRS)

    Hill, D. J.; Haywood, A. M.; Lunt, D. J.; Hunter, S. J.; Bragg, F. J.; Contoux, C.; Stepanek, C.; Sohl, L.; Rosenbloom, N. A.; Chan, W.-L.; Kamae, Y.; Zhang, Z.; Abe-Ouchi, A.; Chandler, M. A.; Jost, A.; Lohmann, G.; Otto-Bliesner, B. L.; Ramstein, G.; Ueda, H.

    2014-01-01

    The Pliocene Model Intercomparison Project (PlioMIP) is the first coordinated climate model comparison for a warmer palaeoclimate with atmospheric CO2 significantly higher than pre-industrial concentrations. The simulations of the mid-Pliocene warm period show global warming of between 1.8 and 3.6 C above pre-industrial surface air temperatures, with significant polar amplification. Here we perform energy balance calculations on all eight of the coupled ocean-atmosphere simulations within PlioMIP Experiment 2 to evaluate the causes of the increased temperatures and differences between the models. In the tropics simulated warming is dominated by greenhouse gas increases, with the cloud component of planetary albedo enhancing the warming in most of the models, but by widely varying amounts. The responses to mid-Pliocene climate forcing in the Northern Hemisphere midlatitudes are substantially different between the climate models, with the only consistent response being a warming due to increased greenhouse gases. In the high latitudes all the energy balance components become important, but the dominant warming influence comes from the clear sky albedo, only partially offset by the increases in the cooling impact of cloud albedo. This demonstrates the importance of specified ice sheet and high latitude vegetation boundary conditions and simulated sea ice and snow albedo feedbacks. The largest components in the overall uncertainty are associated with clouds in the tropics and polar clear sky albedo, particularly in sea ice regions. These simulations show that albedo feedbacks, particularly those of sea ice and ice sheets, provide the most significant enhancements to high latitude warming in the Pliocene.

  14. Effects of Arctic warming on Eurasian climate

    NASA Astrophysics Data System (ADS)

    Uotila, Petteri; Vihma, Timo

    2015-04-01

    The rapid warming in the Arctic has been one of the most dramatic signs of the climate change during the last decades. Arctic warming has been at least twice as fast as the global mean. Simultaneously with the strong warming in the central Arctic, an increased occurrence of extreme weather events, often of unprecedented strength and duration, has already been observed in the northern hemisphere. In this study we address the effects of Arctic warming patterns on climate extremes in Eurasia, and on the atmospheric circulation linking the Arctic with the mid-latitudes. Our objective is to enhance the understanding of the regional differences in the Arctic-mid-latitude linkages, which is an issue that has received a little attention in previous studies. We focus on the period since 1979, when high quality atmospheric reanalysis data are available. We apply the Self-Organizing Maps (SOMs) to extract the geographical patterns of Arctic surface temperature and relate these patterns with composites of atmospheric circulation and climate extreme indices. The extreme indices data are derived from the observational HadEX2 data set. We recognise the fact that the remote effects of Arctic warming may occur with a time lag of several weeks. Therefore we compare Arctic surface temperature patterns and temporally lagged composites of atmospheric circulation and climate extreme data. We compute the frequencies of occurrence of Arctic surface temperature patterns and decompose changes in relevant quantities, such as precipitation, into two components. The first component represents quantity changes associated with changes in frequencies of occurrence of temperature patterns, whilst the second component describes quantity changes due to the local temperature change within each surface temperature pattern. Our preliminary results demonstrate fundamental differences in the Arctic-mid-latitude linkages between the western and central parts of the Eurasian continent. For example, in autumn and early winter, the sea ice cover and air temperatures have a different relationship in the western and central Eurasia, but in late winter their statistical relationships turn similar. Furthermore, frequencies of occurrence of Arctic temperature change significantly from the 1980s until the latest decade. These frequency changes are associated with a particularly distinct reorganisation of the atmospheric circulation over Eurasia, while elsewhere the largest contribution to the atmospheric circulation change in the Northern Hemisphere is associated with local changes in Arctic surface temperatures. We are carrying out more analysis with the SOM technique to different seasons and variables that can provide further insights on the Arctic-mid-latitude linkages.

  15. Ocean change around Greenland under a warming climate

    NASA Astrophysics Data System (ADS)

    Lique, Camille; Johnson, Helen L.; Plancherel, Yves; Flanders, Robert

    2015-09-01

    The impact of climate warming on the ocean near Greenland is investigated with a high resolution coupled global climate model. The ocean around Greenland exhibits a strong warming in response to a four times increase of present-day atmospheric levels. The signal is intensified in the intermediate layer and regionally strongest in the Greenland Sea. The projected changes in temperature are driven by changes affecting the large-scale ocean circulation rather than changes of the local atmospheric heat forcing. The ocean conditions examined here provide a background for the water masses in contact with the outlet glaciers around the Greenland coast. The future warming of the warm subtropical-origin layer could thus lead to enhanced ice sheet melting, although the signal could be mitigated by other effects, including an enhanced stratification of the surface fresh layer. Applying a simple parameterization to estimate the change in melt rate along the Greenland coast, we find that ice sheet melting increases everywhere in response to the change in water mass properties, although the melt rate changes show large variations in space. The largest melting acceleration is found on the east coast between Fram Strait and Denmark Strait, where both the parameterization applied to present-day conditions and observations suggest moderate melting up to now. These model results caution that the Greenland Ice Sheet mass balance should be monitored everywhere and not only where melting occurs at the moment.

  16. Lagging adaptation to warming climate in Arabidopsis thaliana.

    PubMed

    Wilczek, Amity M; Cooper, Martha D; Korves, Tonia M; Schmitt, Johanna

    2014-06-01

    If climate change outpaces the rate of adaptive evolution within a site, populations previously well adapted to local conditions may decline or disappear, and banked seeds from those populations will be unsuitable for restoring them. However, if such adaptational lag has occurred, immigrants from historically warmer climates will outperform natives and may provide genetic potential for evolutionary rescue. We tested for lagging adaptation to warming climate using banked seeds of the annual weed Arabidopsis thaliana in common garden experiments in four sites across the species' native European range: Valencia, Spain; Norwich, United Kingdom; Halle, Germany; and Oulu, Finland. Genotypes originating from geographic regions near the planting site had high relative fitness in each site, direct evidence for broad-scale geographic adaptation in this model species. However, genotypes originating in sites historically warmer than the planting site had higher average relative fitness than local genotypes in every site, especially at the northern range limit in Finland. This result suggests that local adaptive optima have shifted rapidly with recent warming across the species' native range. Climatic optima also differed among seasonal germination cohorts within the Norwich site, suggesting that populations occurring where summer germination is common may have greater evolutionary potential to persist under future warming. If adaptational lag has occurred over just a few decades in banked seeds of an annual species, it may be an important consideration for managing longer-lived species, as well as for attempts to conserve threatened populations through ex situ preservation. PMID:24843140

  17. Climatic warming disrupts recurrent Alpine insect outbreaks

    PubMed Central

    Johnson, Derek M.; Büntgen, Ulf; Frank, David C.; Kausrud, Kyrre; Haynes, Kyle J.; Liebhold, Andrew M.; Esper, Jan; Stenseth, Nils Chr.

    2010-01-01

    Climate change has been identified as a causal factor for diverse ecological changes worldwide. Warming trends over the last couple of decades have coincided with the collapse of long-term population cycles in a broad range of taxa, although causal mechanisms are not well-understood. Larch budmoth (LBM) population dynamics across the European Alps, a classic example of regular outbreaks, inexplicably changed sometime during the 1980s after 1,200 y of nearly uninterrupted periodic outbreak cycles. Herein, analysis of perhaps the most extensive spatiotemporal dataset of population dynamics and reconstructed Alpine-wide LBM defoliation records reveals elevational shifts in LBM outbreak epicenters that coincide with temperature fluctuations over two centuries. A population model supports the hypothesis that temperature-mediated shifting of the optimal elevation for LBM population growth is the mechanism for elevational epicenter changes. Increases in the optimal elevation for population growth over the warming period of the last century to near the distributional limit of host larch likely dampened population cycles, thereby causing the collapse of a millennium-long outbreak cycle. The threshold-like change in LBM outbreak pattern highlights how interacting species with differential response rates to climate change can result in dramatic ecological changes. PMID:21059922

  18. Comment on "Global Genetic Change Tracks Global Climate Warming in

    E-print Network

    Rodríguez, Miguel Ángel

    Comment on "Global Genetic Change Tracks Global Climate Warming in Drosophila subobscura" Francisco in response to global warming. However, that conclusion is not adequately buttressed by their data, because that chromosomal inversion polymorphisms of Drosophila subobscura are evolving in response to global warming. (2

  19. Contrasting the Hydrological Cycle in Past and Future Warm Climates

    NASA Astrophysics Data System (ADS)

    Fedorov, A. V.; Burls, N.

    2014-12-01

    Warm epochs of the past, from the Cretaceous to the Eocene to the Pliocene, are believed to have had generally wetter climate conditions than cold epochs. In particular, vast subtropical regions had enough precipitation to support rich vegetation and fauna. Only with global cooling and the onset of glacial cycles some 3 million years ago did the broad pattern of arid and semi-arid subtropical regions become fully established. However, current projections for future global warming caused by CO2 rise suggest the strengthening of such dry conditions over subtropical regions, rather than the return to a wetter state. What makes these past warm climates so different from future projections? Here, we investigate this question by comparing a typical quadrupling-of-CO2 experiment with an early Pliocene simulation that closely reproduces the available observations. We argue that different cloud properties, maintaining low-latitude ocean temperature patterns with reduced zonal and meridional temperature gradients and hence weaker atmospheric circulation, could explain this puzzle.

  20. OIKOS 97: 5258, 2002 Artificial climate warming positively affects arbuscular

    E-print Network

    Rilli, Matthias C.

    for soil carbon storage and erosion in a warmed climate, especially if there are cumulative effects. Artificial climate warming positively affects arbuscular mycorrhizae but decreases soil aggregate water or production, hence influencing the role of these symbionts in soil aggregation. The observed small changes

  1. Effect of ocean gateway changes under past equable warm climates

    NASA Astrophysics Data System (ADS)

    Sijp, W. P.; England, M. H.

    2008-12-01

    The role of tectonic Southern Ocean gateway changes in driving Antarctic climate change at the Eocene/ Oligocene boundary remains a topic of debate. Here, we find a significantly greater sensitivity of Antarctic temperatures to Southern Ocean gateway changes when atmospheric CO2 concentrations are high. In particular, the closure of the Drake Passage (DP) gap is a necessary condition for the existence of ice-free Antarctic conditions at high CO2 concentrations in our coupled climate model. The absence of the Antarctic Circumpolar Current (ACC) is particularly conducive to warm Eocene Antarctic conditions at higher CO2 concentrations, markedly different to previous simulations conducted under present-day CO2 conditions. Antarctic sea surface temperature and surface air temperature warming due to a closed DP gap reach values around ~5C and ~7C respectively for high concentrations of CO2 (above 1250 ppm). In other words, we find a significantly greater sensitivity of Antarctic temperatures to atmospheric CO2 concentration when the DP is closed. The thermal isolation of Antarctica arising from the development of the ACC inhibits a return to the warmer Antarctic and deep ocean conditions resembling the Eocene, even under enhanced atmospheric greenhouse gas concentrations.

  2. How to preserve the tundra in a warming climate?

    NASA Astrophysics Data System (ADS)

    Käyhkö, Jukka

    2014-05-01

    The warming climate of the polar regions may change much of the current arctic-alpine tundra to forest or dense scrubland. This modification requires adaptation by traditional livelihoods such as reindeer herding, which relies on diverse, seasonal pasturelands. Vegetation change may also trigger positive warming feedbacks, where more abundant forest-scrub vegetation will decrease the global albedo. NCoE Tundra team investigates the complex climate-animal-plant interaction of the tundra ecosystem and aim to unravel the capability of herbivorous mammals to control the expansion of woody vegetation. Our interdisciplinary approach involves several work packages, whose results will be summarised in the presentation. In the ecological WPs, we study the dynamics of the natural food chains involving small herbivorous and the impacts of reindeer on the vegetation and the population dynamics of those arctic-alpine plants, which are most likely to become threatened in a warmer climate. Our study demonstrates the potential of a relatively sparse reindeer stocks (2-5 heads per km2) together with natural populations of arvicoline rodents to prevent the expansion of erect woody plants at the arctic-alpine timberline. In the climatic WPs we study the impact of grazing-dependent vegetation differences on the fraction of solar energy converted to heat. In the socio-economic WPs, we study the conditions for maintaining the economic and cultural viability of reindeer herding while managing the land use so that the arctic-alpine biota would be preserved.

  3. Modelling middle pliocene warm climates of the USA

    USGS Publications Warehouse

    Haywood, A.M.; Valdes, P.J.; Sellwood, B.W.; Kaplan, J.O.; Dowsett, H.J.

    2001-01-01

    The middle Pliocene warm period represents a unique time slice in which to model and understand climatic processes operating under a warm climatic regime. Palaeoclimatic model simulations, focussed on the United States of America (USA), for the middle Pliocene (ca 3 Ma) were generated using the USGS PRISM2 2?? ?? 2?? data set of boundary conditions and the UK Meteorological Office's HadAMS General Circulation Model (GCM). Model results suggest that conditions in the USA during the middle Pliocene can be characterised as annually warmer (by 2?? to 4??C), less seasonal, wetter (by a maximum of 4 to 8 mm/day) and with an absence of freezing winters over the central and southern Great Plains. A sensitivity experiment suggests that the main forcing mechanisms for surface temperature changes in near coastal areas are the imposed Pliocene sea surface temperatures (SST's). In interior regions, reduced Northern Hemisphere terrestrial ice, combined with less snow cover and a reduction in the elevation of the western cordillera of North America, generate atmospheric circulation changes and positive albedo feedbacks that raise surface temperatures. A complex set of climatic feedback mechanisms cause an enhancement of the hydrological cycle magnifying the moisture bearing westerly wind belt during the winter season (Dec., Jan., Feb.). Predictions produced by the model are in broad agreement with available geological evidence. However, the GCM appears to underestimate precipitation levels in the interior and central regions of the southern USA. Copyright: Palaeontological Association, 22 June 2001.

  4. Ocean biogeochemistry in the warm climate of the late Paleocene

    NASA Astrophysics Data System (ADS)

    Heinze, M.; Ilyina, T.

    2015-01-01

    The late Paleocene is characterized by warm and stable climatic conditions that served as the background climate for the Paleocene-Eocene Thermal Maximum (PETM, ~55 million years ago). With respect to feedback processes in the carbon cycle, the ocean biogeochemical background state is of major importance for projecting the climatic response to a carbon perturbation related to the PETM. Therefore, we use the Hamburg Ocean Carbon Cycle model (HAMOCC), embedded in the ocean general circulation model of the Max Planck Institute for Meteorology, MPIOM, to constrain the ocean biogeochemistry of the late Paleocene. We focus on the evaluation of modeled spatial and vertical distributions of the ocean carbon cycle parameters in a long-term warm steady-state ocean, based on a 560 ppm CO2 atmosphere. Model results are discussed in the context of available proxy data and simulations of pre-industrial conditions. Our results illustrate that ocean biogeochemistry is shaped by the warm and sluggish ocean state of the late Paleocene. Primary production is slightly reduced in comparison to the present day; it is intensified along the Equator, especially in the Atlantic. This enhances remineralization of organic matter, resulting in strong oxygen minimum zones and CaCO3 dissolution in intermediate waters. We show that an equilibrium CO2 exchange without increasing total alkalinity concentrations above today's values is achieved. However, consistent with the higher atmospheric CO2, the surface ocean pH and the saturation state with respect to CaCO3 are lower than today. Our results indicate that, under such conditions, the surface ocean carbonate chemistry is expected to be more sensitive to a carbon perturbation (i.e., the PETM) due to lower CO32- concentration, whereas the deep ocean calcite sediments would be less vulnerable to dissolution due to the vertically stratified ocean.

  5. Simulating forest ecosystem response to climate warming incorporating spatial

    E-print Network

    He, Hong S.

    using gap models, which are among the most effective tools for assessing the effects of climate change beyond the simulation plots and are important under changing climates. In this study we incorporate (establishment) of individual species to climate warming are simulated using a gap model (linkages) that has been

  6. Tropical Cyclogenesis Factors in a Warming Climate 

    E-print Network

    Cathey, Stephen Christopher

    2012-02-14

    Understanding the underlying causes of tropical cyclone formation is crucial to predicting tropical cyclone behavior in a warming environment, given the Earth's current warming trend. This study examines two sets of simulations from the National...

  7. Talking about Climate Change and Global Warming

    PubMed Central

    Kim, Ji Yoon; Joo, Gea-Jae

    2015-01-01

    The increasing prevalence of social networks provides researchers greater opportunities to evaluate and assess changes in public opinion and public sentiment towards issues of social consequence. Using trend and sentiment analysis is one method whereby researchers can identify changes in public perception that can be used to enhance the development of a social consciousness towards a specific public interest. The following study assessed Relative search volume (RSV) patterns for global warming (GW) and Climate change (CC) to determine public knowledge and awareness of these terms. In conjunction with this, the researchers looked at the sentiment connected to these terms in social media networks. It was found that there was a relationship between the awareness of the information and the amount of publicity generated around the terminology. Furthermore, the primary driver for the increase in awareness was an increase in publicity in either a positive or a negative light. Sentiment analysis further confirmed that the primary emotive connections to the words were derived from the original context in which the word was framed. Thus having awareness or knowledge of a topic is strongly related to its public exposure in the media, and the emotional context of this relationship is dependent on the context in which the relationship was originally established. This has value in fields like conservation, law enforcement, or other fields where the practice can and often does have two very strong emotive responses based on the context of the problems being examined. PMID:26418127

  8. Soil respiration under climate warming: differential response of heterotrophic and autotrophic respiration.

    PubMed

    Wang, Xin; Liu, Lingli; Piao, Shilong; Janssens, Ivan A; Tang, Jianwu; Liu, Weixing; Chi, Yonggang; Wang, Jing; Xu, Shan

    2014-10-01

    Despite decades of research, how climate warming alters the global flux of soil respiration is still poorly characterized. Here, we use meta-analysis to synthesize 202 soil respiration datasets from 50 ecosystem warming experiments across multiple terrestrial ecosystems. We found that, on average, warming by 2 °C increased soil respiration by 12% during the early warming years, but warming-induced drought partially offset this effect. More significantly, the two components of soil respiration, heterotrophic respiration and autotrophic respiration showed distinct responses. The warming effect on autotrophic respiration was not statistically detectable during the early warming years, but nonetheless decreased with treatment duration. In contrast, warming by 2 °C increased heterotrophic respiration by an average of 21%, and this stimulation remained stable over the warming duration. This result challenged the assumption that microbial activity would acclimate to the rising temperature. Together, our findings demonstrate that distinguishing heterotrophic respiration and autotrophic respiration would allow us better understand and predict the long-term response of soil respiration to warming. The dependence of soil respiration on soil moisture condition also underscores the importance of incorporating warming-induced soil hydrological changes when modeling soil respiration under climate change. PMID:24771521

  9. Why tropical forest lizards are vulnerable to climate warming

    PubMed Central

    Huey, Raymond B.; Deutsch, Curtis A.; Tewksbury, Joshua J.; Vitt, Laurie J.; Hertz, Paul E.; Álvarez Pérez, Héctor J.; Garland, Theodore

    2009-01-01

    Biological impacts of climate warming are predicted to increase with latitude, paralleling increases in warming. However, the magnitude of impacts depends not only on the degree of warming but also on the number of species at risk, their physiological sensitivity to warming and their options for behavioural and physiological compensation. Lizards are useful for evaluating risks of warming because their thermal biology is well studied. We conducted macrophysiological analyses of diurnal lizards from diverse latitudes plus focal species analyses of Puerto Rican Anolis and Sphaerodactyus. Although tropical lowland lizards live in environments that are warm all year, macrophysiological analyses indicate that some tropical lineages (thermoconformers that live in forests) are active at low body temperature and are intolerant of warm temperatures. Focal species analyses show that some tropical forest lizards were already experiencing stressful body temperatures in summer when studied several decades ago. Simulations suggest that warming will not only further depress their physiological performance in summer, but will also enable warm-adapted, open-habitat competitors and predators to invade forests. Forest lizards are key components of tropical ecosystems, but appear vulnerable to the cascading physiological and ecological effects of climate warming, even though rates of tropical warming may be relatively low. PMID:19324762

  10. Modeling the Impact of Warming in Climate Change Economics

    E-print Network

    Pindyck, Robert S.

    Any economic analysis of climate change policy requires some model that describes the impact of warming on future GDP and consumption. Most integrated assessment models (IAMs) relate temperature to the level of real GDP ...

  11. The Climate Policy Narrative for a Dangerously Warming World

    SciTech Connect

    Sanford, Todd; Frumhoff, Peter; Luers, Amy; Gulledge, Jay

    2014-01-01

    It is time to acknowledge that global average temperatures will likely rise above the 2 C policy target and consider how that deeply troubling prospect should affect priorities for communicating and managing the risks of a dangerously warming climate.

  12. Warm rain and climate: VOCALS, CloudSat, Models

    E-print Network

    Wood, Robert

    to be taken to compare model with CloudSat: (1) Use model assumed precipitation DSD to determine radar1 of cloud liquid q water (Lhermitte 1990) #12;Reflectivity in [LWP, Nd] space IncreasingWarm rain and climate: VOCALS, CloudSat, Models Robert Wood University of Washington #12;Warm

  13. Transitivity of the climate-vegetation system in a warm climate

    NASA Astrophysics Data System (ADS)

    Port, U.; Claussen, M.

    2015-11-01

    To date, the transitivity of the global system has been analysed for late Quaternary (glacial, interglacial, and present-day) climate. Here, we extend this analysis to a warm, almost ice-free climate with a different configuration of continents. We use the Earth system model of the Max Planck Institute for Meteorology to analyse the stability of the climate system under early Eocene and pre-industrial conditions. We initialize the simulations by prescribing either dense forests or bare deserts on all continents. Starting with desert continents, an extended desert remains in central Asia in the early Eocene climate. Starting with dense forest coverage, the Asian desert is much smaller, while coastal deserts develop in the Americas which appear to be larger than in the simulations with initially bare continents. These differences can be attributed to differences in the large-scale tropical circulation. With initially forested continents, a stronger dipole in the 200 hPa velocity potential develops than in the simulation with initially bare continents. This difference prevails when vegetation is allowed to adjust to and interact with climate. Further simulations with initial surface conditions that differ in the region of the Asian desert only indicate that local feedback processes are less important in the development of multiple states. In the interglacial, pre-industrial climate, multiple states develop only in the Sahel region. There, local climate-vegetation interaction seems to dominate.

  14. Simulated increase of hurricane intensities in a CO{sub 2}-warmed climate

    SciTech Connect

    Knutson, T.R.; Tuleya, R.E.; Kurihara, Y.

    1998-02-13

    Hurricanes can inflict catastrophic property damage and loss of human life. Thus, it is important to determine how the character of these powerful storms could change in response to greenhouse gas-induced global warming. The impact of climate warming on hurricane intensities was investigated with a regional, high-resolution, hurricane prediction model. In a case study, 51 western Pacific storm cases under present-day climate conditions were compared with 51 storm cases under high-CO{sub 2} conditions. More idealized experiments were also performed. The large-scale initial conditions were derived from a global climate model. For a sea surface temperature warming of about 2.2{degree}C, the simulations yielded hurricanes that were more intense by 3 to 7 meters per second (5 to 12 percent) for wind speed and 7 to 20 millibars for central surface pressure. 26 refs., 4 figs.

  15. Phenological sequences reveal aggregate life history response to climatic warming.

    PubMed

    Post, Eric S; Pedersen, Christian; Wilmers, Christopher C; Forchhammer, Mads C

    2008-02-01

    Climatic warming is associated with organisms breeding earlier in the season than is typical for their species. In some species, however, response to warming is more complex than a simple advance in the timing of all life history events preceding reproduction. Disparities in the extent to which different components of the reproductive phenology of organisms vary with climatic warming indicate that not all life history events are equally responsive to environmental variation. Here, we propose that our understanding of phenological response to climate change can be improved by considering entire sequences of events comprising the aggregate life histories of organisms preceding reproduction. We present results of a two-year warming experiment conducted on 33 individuals of three plant species inhabiting a low-arctic site. Analysis of phenological sequences of three key events for each species revealed how the aggregate life histories preceding reproduction responded to warming, and which individual events exerted the greatest influence on aggregate life history variation. For alpine chickweed (Cerastium alpinum), warming elicited a shortening of the duration of the emergence stage by 2.5 days on average, but the aggregate life history did not differ between warmed and ambient plots. For gray willow (Salix glauca), however, all phenological events monitored occurred earlier on warmed than on ambient plots, and warming reduced the aggregate life history of this species by 22 days on average. Similarly, in dwarf birch (Betula nana), warming advanced flower bud set, blooming, and fruit set and reduced the aggregate life history by 27 days on average. Our approach provides important insight into life history responses of many organisms to climate change and other forms of environmental variation. Such insight may be compromised by considering changes in individual phenological events in isolation. PMID:18409426

  16. Climatic unpredictability and parasitism of caterpillars: Implications of global warming

    E-print Network

    Stireman III, John O.

    Climatic unpredictability and parasitism of caterpillars: Implications of global warming J. O variability itself on species interactions has been little explored. Here, we compare caterpillar­parasitoid geographically dispersed databases show a decrease in levels of parasitism as climatic variability increases

  17. Biomass production in experimental grasslands of different species richness during three years of climate warming

    NASA Astrophysics Data System (ADS)

    de Boeck, H. J.; Lemmens, C. M. H. M.; Zavalloni, C.; Gielen, B.; Malchair, S.; Carnol, M.; Merckx, R.; van den Berge, J.; Ceulemans, R.; Nijs, I.

    2008-04-01

    Here we report on the single and combined impacts of climate warming and species richness on the biomass production in experimental grassland communities. Projections of a future warmer climate have stimulated studies on the response of terrestrial ecosystems to this global change. Experiments have likewise addressed the importance of species numbers for ecosystem functioning. There is, however, little knowledge on the interplay between warming and species richness. During three years, we grew experimental plant communities containing one, three or nine grassland species in 12 sunlit, climate-controlled chambers in Wilrijk, Belgium. Half of these chambers were exposed to ambient air temperatures (unheated), while the other half were warmed by 3°C (heated). Equal amounts of water were added to heated and unheated communities, so that warming would imply drier soils if evapotranspiration was higher. Biomass production was decreased due to warming, both aboveground (-29%) and belowground (-25%), as negative impacts of increased heat and drought stress in summer prevailed. Complementarity effects, likely mostly through both increased aboveground spatial complementarity and facilitative effects of legumes, led to higher shoot and root biomass in multi-species communities, regardless of the induced warming. Surprisingly, warming suppressed productivity the most in 9-species communities, which may be attributed to negative impacts of intense interspecific competition for resources under conditions of high abiotic stress. Our results suggest that warming and the associated soil drying could reduce primary production in many temperate grasslands, and that this will not necessarily be mitigated by efforts to maintain or increase species richness.

  18. Terrestrial carbon cycle affected by non-uniform climate warming

    NASA Astrophysics Data System (ADS)

    Xia, Jianyang; Chen, Jiquan; Piao, Shilong; Ciais, Philippe; Luo, Yiqi; Wan, Shiqiang

    2014-03-01

    Feedbacks between the terrestrial carbon cycle and climate change could affect many ecosystem functions and services, such as food production, carbon sequestration and climate regulation. The rate of climate warming varies on diurnal and seasonal timescales. A synthesis of global air temperature data reveals a greater rate of warming in winter than in summer in northern mid and high latitudes, and the inverse pattern in some tropical regions. The data also reveal a decline in the diurnal temperature range over 51% of the global land area and an increase over only 13%, because night-time temperatures in most locations have risen faster than daytime temperatures. Analyses of satellite data, model simulations and in situ observations suggest that the impact of seasonal warming varies between regions. For example, spring warming has largely stimulated ecosystem productivity at latitudes between 30° and 90° N, but suppressed productivity in other regions. Contrasting impacts of day- and night-time warming on plant carbon gain and loss are apparent in many regions. We argue that ascertaining the effects of non-uniform climate warming on terrestrial ecosystems is a key challenge in carbon cycle research.

  19. Global Warming What is Climate? Ocean's Role in Climate Change Uncertainty Quantification, the Next Frontier The Role Played by Oceans in Climate

    E-print Network

    Restrepo, Juan M.

    Global Warming What is Climate? Ocean's Role in Climate Change Uncertainty Quantification, the Next Department University of Arizona October 11, 2008 #12;Global Warming What is Climate? Ocean's Role in Climate, Undergraduate Students: 2. UQGQG #12;Global Warming What is Climate? Ocean's Role in Climate Change Uncertainty

  20. Seasonal Climate Extremes : Mechanism, Predictability and Responses to Global Warming

    NASA Astrophysics Data System (ADS)

    Shongwe, M. E.

    2010-01-01

    Climate extremes are rarely occurring natural phenomena in the climate system. They often pose one of the greatest environmental threats to human and natural systems. Statistical methods are commonly used to investigate characteristics of climate extremes. The fitted statistical properties are often interpolated or extrapolated to give an indication of the likelihood of a certain event within a given period or interval. Under changing climatic conditions, the statistical properties of climate extremes are also changing. It is an important scientific goal to predict how the properties of extreme events change. To achieve this goal, observational and model studies aimed at revealing important features are a necessary prerequisite. Notable progress has been made in understanding mechanisms that influence climate variability and extremes in many parts of the globe including Europe. However, some of the recently observed unprecedented extremes cannot be fully explained from the already identified forcing factors. A better understanding of why these extreme events occur and their sensitivity to certain reinforcing and/or competing factors is useful. Understanding their basic form as well as their temporal variability is also vital and can contribute to global scientific efforts directed at advancing climate prediction capabilities, particularly making skilful forecasts and realistic projections of extremes. In this thesis temperature and precipitation extremes in Europe and Africa, respectively, are investigated. Emphasis is placed on the mechanisms underlying the occurrence of the extremes, their predictability and their likely response to global warming. The focus is on some selected seasons when extremes typically occur. An atmospheric energy budget analysis for the record-breaking European Autumn 2006 event has been carried out with the goal to identify the sources of energy for the extreme event. Net radiational heating is compared to surface turbulent fluxes of energy and dynamic horizontal advection of heat. There is clear evidence that the central North Atlantic Ocean was the major source of energy for the Autumn 2006 extreme event. Within Europe, anomalously high atmospheric water-vapor loading played a significant role through its strong greenhouse effect which resulted in an increase of downwelling infrared flux to the surface. Potential influences and connections between boreal snow cover during the melt season (February--April) and near-surface temperature in the spring season are established. Large amounts of snow act as a precursor to cold spring seasons by altering the coupling between the land and the overlying air through a modification of the surface energy and hydrological processes. In operational numerical models, a snow signal is found to provide some seasonal forecast skill for cold spring seasons in Europe. Changes in the intensity of droughts and floods in Africa in response to global warming are investigated and compared with changes in mean precipitation simulated by an ensemble of climate models selected from the Intergovernmental Panel on Climate Change (IPCC) fourth assessment report (AR4) set. The model simulations are objectively combined using a Bayesian weighting procedure. In southern Africa south of about 15° S, the most robust climate-change signal is a shortening of the main rainfall season. This arises from a delayed onset of seasonal rainfall associated with a reduction in lower-tropospheric moisture advection from the southwestern Indian Ocean. The semi-arid areas closer to the Kalahari desert are projected to become drier, while the wet areas are projected to become wetter. East Africa is projected to get wet in the future climate, much wetter than other regions within the same latitudinal belt. The zonal asymmetry in tropical precipitation increase is associated with a shift towards positive Indian Ocean Zonal Mode (IOZM)-like events via an alteration in the structure of the Eastern Hemisphere Walker circulation.

  1. The long-term fate of permafrost peatlands under rapid climate warming

    PubMed Central

    Swindles, Graeme T.; Morris, Paul J.; Mullan, Donal; Watson, Elizabeth J.; Turner, T. Edward; Roland, Thomas P.; Amesbury, Matthew J.; Kokfelt, Ulla; Schoning, Kristian; Pratte, Steve; Gallego-Sala, Angela; Charman, Dan J.; Sanderson, Nicole; Garneau, Michelle; Carrivick, Jonathan L.; Woulds, Clare; Holden, Joseph; Parry, Lauren; Galloway, Jennifer M.

    2015-01-01

    Permafrost peatlands contain globally important amounts of soil organic carbon, owing to cold conditions which suppress anaerobic decomposition. However, climate warming and permafrost thaw threaten the stability of this carbon store. The ultimate fate of permafrost peatlands and their carbon stores is unclear because of complex feedbacks between peat accumulation, hydrology and vegetation. Field monitoring campaigns only span the last few decades and therefore provide an incomplete picture of permafrost peatland response to recent rapid warming. Here we use a high-resolution palaeoecological approach to understand the longer-term response of peatlands in contrasting states of permafrost degradation to recent rapid warming. At all sites we identify a drying trend until the late-twentieth century; however, two sites subsequently experienced a rapid shift to wetter conditions as permafrost thawed in response to climatic warming, culminating in collapse of the peat domes. Commonalities between study sites lead us to propose a five-phase model for permafrost peatland response to climatic warming. This model suggests a shared ecohydrological trajectory towards a common end point: inundated Arctic fen. Although carbon accumulation is rapid in such sites, saturated soil conditions are likely to cause elevated methane emissions that have implications for climate-feedback mechanisms. PMID:26647837

  2. The long-term fate of permafrost peatlands under rapid climate warming.

    PubMed

    Swindles, Graeme T; Morris, Paul J; Mullan, Donal; Watson, Elizabeth J; Turner, T Edward; Roland, Thomas P; Amesbury, Matthew J; Kokfelt, Ulla; Schoning, Kristian; Pratte, Steve; Gallego-Sala, Angela; Charman, Dan J; Sanderson, Nicole; Garneau, Michelle; Carrivick, Jonathan L; Woulds, Clare; Holden, Joseph; Parry, Lauren; Galloway, Jennifer M

    2015-01-01

    Permafrost peatlands contain globally important amounts of soil organic carbon, owing to cold conditions which suppress anaerobic decomposition. However, climate warming and permafrost thaw threaten the stability of this carbon store. The ultimate fate of permafrost peatlands and their carbon stores is unclear because of complex feedbacks between peat accumulation, hydrology and vegetation. Field monitoring campaigns only span the last few decades and therefore provide an incomplete picture of permafrost peatland response to recent rapid warming. Here we use a high-resolution palaeoecological approach to understand the longer-term response of peatlands in contrasting states of permafrost degradation to recent rapid warming. At all sites we identify a drying trend until the late-twentieth century; however, two sites subsequently experienced a rapid shift to wetter conditions as permafrost thawed in response to climatic warming, culminating in collapse of the peat domes. Commonalities between study sites lead us to propose a five-phase model for permafrost peatland response to climatic warming. This model suggests a shared ecohydrological trajectory towards a common end point: inundated Arctic fen. Although carbon accumulation is rapid in such sites, saturated soil conditions are likely to cause elevated methane emissions that have implications for climate-feedback mechanisms. PMID:26647837

  3. Impacts of a Warming Arctic - Arctic Climate Impact Assessment

    NASA Astrophysics Data System (ADS)

    Arctic Climate Impact Assessment

    2004-12-01

    The Arctic is now experiencing some of the most rapid and severe climate change on earth. Over the next 100 years, climate change is expected to accelerate, contributing to major physical, ecological, social, and economic changes, many of which have already begun. Changes in arctic climate will also affect the rest of the world through increased global warming and rising sea levels. Impacts of a Warming Arctic is a plain language synthesis of the key findings of the Arctic Climate Impact Assessment (ACIA), designed to be accessible to policymakers and the broader public. The ACIA is a comprehensively researched, fully referenced, and independently reviewed evaluation of arctic climate change. It has involved an international effort by hundreds of scientists. This report provides vital information to society as it contemplates its responses to one of the greatest challenges of our time. It is illustrated in full color throughout.

  4. The case for a wet, warm climate on early Mars.

    PubMed

    Pollack, J B; Kasting, J F; Richardson, S M; Poliakoff, K

    1987-01-01

    Theoretical arguments are presented in support of the idea that Mars possessed a dense CO2 atmosphere and a wet, warm climate early in its history. Calculations with a one-dimensional radiative-convective climate model indicate that CO2 pressures between 1 and 5 bars would have been required to keep the surface temperature above the freezing point of water early in the planet's history. The higher value corresponds to globally and orbitally averaged conditions and a 30% reduction in solar luminosity; the lower value corresponds to conditions at the equator during perihelion at times of high orbital eccentricity and the same reduced solar luminosity. The plausibility of such a CO2 greenhouse is tested by formulating a simple model of the CO2 geochemical cycle on early Mars. By appropriately scaling the rate of silicate weathering on present Earth, we estimate a weathering time constant of the order of several times 10(7) years for early Mars. Thus, a dense atmosphere could have persisted for a geologically significant time period (approximately 10(9) years) only if atmospheric CO2 was being continuously resupplied. The most likely mechanism by which this might have been accomplished is the thermal decomposition of carbonate rocks induced directly and indirectly (through burial) by intense, global-scale volcanism. For plausible values of the early heat flux, the recycling time constant is also of the order of several times 10(7) years. The amount of CO2 dissolved in standing bodies of water was probably small; thus, the total surficial CO2 inventory required to maintain these conditions was approximately 2 to 10 bars. The amount of CO2 in Mars' atmosphere would eventually have dwindled, and the climate cooled, as the planet's internal heat engine ran down. A test for this theory will be provided by spectroscopic searches for carbonates in Mars' crust. PMID:11539035

  5. Geoengineering: Direct Mitigation of Climate Warming

    EPA Science Inventory

    For Frank Princiotta’s book, Global Climate Change—The Technology Challenge With the concentrations of atmospheric greenhouse gases (GHGs) rising to levels unprecedented in the current glacial epoch, the earth’s climate system appears to be rapidly shifting into a warmer regime....

  6. Assessing regional and warming level dependent differences in climate impacts

    NASA Astrophysics Data System (ADS)

    Wohland, Jan; Schleussner, Carl-Friedrich; Lissner, Tabea; Fischer, Erich M.; Frieler, Katja

    2015-04-01

    Differentiation between climate impacts at different levels of warming is of great relevance for scientists and policy makers. Knowledge of the consequences of different development and temperature pathways is essential to inform international climate negotiations and regional adaptation planning alike. At the same time, not only the warming dimension but also the regional dimension of changes in impacts is of interest, since regional changes might not be linearly related to global mean temperature increase. A detailed understanding of regionally differentiated impacts is an important basis on which to develop suitable coping strategies and adaptation options. Here we present a framework that allows for a differentiation of regional changes in climate impacts at different levels of temperature increase. Based on data from the CMIP5 archive as well as output from the AgMIP project, we assess the climate impact projections for an increase in global mean surface air temperature of 1.5 and 2 °C above pre-industrial levels for the 26 regions used in the IPCC SREX report. We show results for several extreme event indices as well as projections of water availability and agricultural yields. Based on a method developed by Fischer et al. (2013), we are able to test for statistical significance of changes in climate impact projections between the different warming levels across the model ensemble. References: Fischer, E. M., Beyerle, U. & Knutti, R. Robust spatially aggregated projections of climate extremes. Nature Climate Change 3, 1033-1038 (2013).

  7. Projected changes of snow conditions and avalanche activity in a warming climate: a case study in the French Alps over the 2020-2050 and 2070-2100 periods

    NASA Astrophysics Data System (ADS)

    Castebrunet, H.; Eckert, N.; Giraud, G.; Durand, Y.; Morin, S.

    2014-01-01

    Projecting changes in snow cover due to climate warming is important for many societal issues, including adaptation of avalanche risk mitigation strategies. Efficient modeling of future snow cover requires high resolution to properly resolve the topography. Here, we detail results obtained through statistical downscaling techniques allowing simulations of future snowpack conditions for the mid- and late 21st century in the French Alps under three climate change scenarios. Refined statistical descriptions of snowpack characteristics are provided with regards to a 1960-1990 reference period, including latitudinal, altitudinal and seasonal gradients. These results are then used to feed a statistical model of avalanche activity-snow conditions-meteorological conditions relationships, so as to produce the first prognoses at annual/seasonal time scales of future natural avalanche activity eventually based on past observations. The resulting statistical indicators are fundamental for the mountain economy in terms of changes anticipation. At all considered spatio-temporal scales, whereas precipitations are expected to remain quite stationary, temperature increase interacting with topography will control snow-related variables, for instance the rate of decrease of total and dry snow depths, and the successive increase/decrease of the wet snow pack. Overall, with regards to the reference period, changes are strong for the end of the 21st century, but already significant for the mid-century. Changes in winter are somewhat less important than in spring, but wet snow conditions will appear at high elevations earlier in the season. For a given altitude, the Southern French Alps will not be significantly more affected than the Northern French Alps, so that the snowpack characteristics will be preserved more lately in the southern massifs of higher mean altitude. Regarding avalanche activity, a general -20-30% decrease and interannual variability is forecasted, relatively strong compared to snow and meteorological parameters changes. This decrease is amplified in spring and at low altitude. In contrast, an increase of avalanche activity is expected in winter at high altitude because of earlier wet snow avalanches triggers, at least as long as a minimal snow cover will be present. Comparison with the outputs of the deterministic avalanche hazard model MEPRA shows generally consistent results but suggests that, even if the frequency of winters with high avalanche activity will clearly decrease, the decreasing trend may be less strong and smooth than suggested by the changes in snowpack characteristics. This important point for risk assessment pleads for further work focusing on shorter time scales. Finally, small differences between different climate change scenarios show the robustness of the predicted avalanche activity changes.

  8. Climatic warming and the future of bison as grazers

    PubMed Central

    Craine, Joseph M.; Towne, E. Gene; Miller, Mary; Fierer, Noah

    2015-01-01

    Climatic warming is likely to exacerbate nutritional stress and reduce weight gain in large mammalian herbivores by reducing plant nutritional quality. Yet accurate predictions of the effects of climatic warming on herbivores are limited by a poor understanding of how herbivore diet varies along climate gradients. We utilized DNA metabarcoding to reconstruct seasonal variation in the diet of North American bison (Bison bison) in two grasslands that differ in mean annual temperature by 6?°C. Here, we show that associated with greater nutritional stress in warmer climates, bison consistently consumed fewer graminoids and more shrubs and forbs, i.e. eudicots. Bison in the warmer grassland consumed a lower proportion of C3 grass, but not a greater proportion of C4 grass. Instead, bison diet in the warmer grassland had a greater proportion of N2-fixing eudicots, regularly comprising >60% of their protein intake in spring and fall. Although bison have been considered strict grazers, as climatic warming reduces grass protein concentrations, bison may have to attempt to compensate by grazing less and browsing more. Promotion of high-protein, palatable eudicots or increasing the protein concentrations of grasses will be critical to minimizing warming-imposed nutritional stress for bison and perhaps other large mammalian herbivores. PMID:26567987

  9. Climatic warming and the future of bison as grazers.

    PubMed

    Craine, Joseph M; Towne, E Gene; Miller, Mary; Fierer, Noah

    2015-01-01

    Climatic warming is likely to exacerbate nutritional stress and reduce weight gain in large mammalian herbivores by reducing plant nutritional quality. Yet accurate predictions of the effects of climatic warming on herbivores are limited by a poor understanding of how herbivore diet varies along climate gradients. We utilized DNA metabarcoding to reconstruct seasonal variation in the diet of North American bison (Bison bison) in two grasslands that differ in mean annual temperature by 6?°C. Here, we show that associated with greater nutritional stress in warmer climates, bison consistently consumed fewer graminoids and more shrubs and forbs, i.e. eudicots. Bison in the warmer grassland consumed a lower proportion of C3 grass, but not a greater proportion of C4 grass. Instead, bison diet in the warmer grassland had a greater proportion of N2-fixing eudicots, regularly comprising >60% of their protein intake in spring and fall. Although bison have been considered strict grazers, as climatic warming reduces grass protein concentrations, bison may have to attempt to compensate by grazing less and browsing more. Promotion of high-protein, palatable eudicots or increasing the protein concentrations of grasses will be critical to minimizing warming-imposed nutritional stress for bison and perhaps other large mammalian herbivores. PMID:26567987

  10. Climatic warming and the future of bison as grazers

    NASA Astrophysics Data System (ADS)

    Craine, Joseph M.; Towne, E. Gene; Miller, Mary; Fierer, Noah

    2015-11-01

    Climatic warming is likely to exacerbate nutritional stress and reduce weight gain in large mammalian herbivores by reducing plant nutritional quality. Yet accurate predictions of the effects of climatic warming on herbivores are limited by a poor understanding of how herbivore diet varies along climate gradients. We utilized DNA metabarcoding to reconstruct seasonal variation in the diet of North American bison (Bison bison) in two grasslands that differ in mean annual temperature by 6?°C. Here, we show that associated with greater nutritional stress in warmer climates, bison consistently consumed fewer graminoids and more shrubs and forbs, i.e. eudicots. Bison in the warmer grassland consumed a lower proportion of C3 grass, but not a greater proportion of C4 grass. Instead, bison diet in the warmer grassland had a greater proportion of N2-fixing eudicots, regularly comprising >60% of their protein intake in spring and fall. Although bison have been considered strict grazers, as climatic warming reduces grass protein concentrations, bison may have to attempt to compensate by grazing less and browsing more. Promotion of high-protein, palatable eudicots or increasing the protein concentrations of grasses will be critical to minimizing warming-imposed nutritional stress for bison and perhaps other large mammalian herbivores.

  11. Implication of climate warming for agricultural production in eastern areas of China

    SciTech Connect

    Wang Futang

    1996-12-31

    Based on historical variation of temperature and precipitation, the potential effects of climate warming on rice, winter wheat and corn production in China are simulated in this paper, using the weather-yield model and cropping system model. As a result, it is shown that under the current planting systems and agrotechniques, the greenhouse climate warming effect upon the corn production is the most significant. Regionally, the meteorological conditions of agricultural production in the northern part of China will be more favorable than the south and the central part. And seasonally speaking, such impact in general will be apparent in Autumn.

  12. Sustained growth of the Southern Ocean carbon storage in a warming climate

    NASA Astrophysics Data System (ADS)

    Ito, Takamitsu; Bracco, Annalisa; Deutsch, Curtis; Frenzel, Hartmut; Long, Matthew; Takano, Yohei

    2015-06-01

    We investigate the mechanisms controlling the evolution of Southern Ocean carbon storage under a future climate warming scenario. A subset of Coupled Model Intercomparison Project Phase 5 models predicts that the inventory of biologically sequestered carbon south of 40°S increases about 18-34 Pg C by 2100 relative to the preindustrial condition. Sensitivity experiments with an ocean circulation and biogeochemistry model illustrates the impacts of the wind and buoyancy forcings under a warming climate. Intensified and poleward shifted westerly wind strengthens the upper overturning circulation, not only leading to an increased uptake of anthropogenic CO2 but also releasing biologically regenerated carbon to the atmosphere. Freshening of Antarctic Surface Water causes a slowdown of the lower overturning circulation, leading to an increased Southern Ocean biological carbon storage. The rectified effect of these processes operating together is the sustained growth of the carbon storage in the Southern Ocean, even under the warming climate with a weaker global ocean carbon uptake.

  13. Impacts of climate warming on terrestrial ectotherms across latitude

    PubMed Central

    Deutsch, Curtis A.; Tewksbury, Joshua J.; Huey, Raymond B.; Sheldon, Kimberly S.; Ghalambor, Cameron K.; Haak, David C.; Martin, Paul R.

    2008-01-01

    The impact of anthropogenic climate change on terrestrial organisms is often predicted to increase with latitude, in parallel with the rate of warming. Yet the biological impact of rising temperatures also depends on the physiological sensitivity of organisms to temperature change. We integrate empirical fitness curves describing the thermal tolerance of terrestrial insects from around the world with the projected geographic distribution of climate change for the next century to estimate the direct impact of warming on insect fitness across latitude. The results show that warming in the tropics, although relatively small in magnitude, is likely to have the most deleterious consequences because tropical insects are relatively sensitive to temperature change and are currently living very close to their optimal temperature. In contrast, species at higher latitudes have broader thermal tolerance and are living in climates that are currently cooler than their physiological optima, so that warming may even enhance their fitness. Available thermal tolerance data for several vertebrate taxa exhibit similar patterns, suggesting that these results are general for terrestrial ectotherms. Our analyses imply that, in the absence of ameliorating factors such as migration and adaptation, the greatest extinction risks from global warming may be in the tropics, where biological diversity is also greatest. PMID:18458348

  14. Climate warming and disease risks for terrestrial and marine biota

    USGS Publications Warehouse

    Harvell, C.D.; Mitchell, C.E.; Ward, J.R.; Altizer, S.; Dobson, A.P.; Ostfeld, R.S.; Samuel, M.D.

    2002-01-01

    Infectious diseases can cause rapid population declines or species extinctions. Many pathogens of terrestrial and marine taxa are sensitive to temperature, rainfall, and humidity, creating synergisms that could affect biodiversity. Climate warming can increase pathogen development and survival rates, disease transmission, and host susceptibility. Although most host-parasite systems are predicted to experience more frequent or severe disease impacts with warming, a subset of pathogens might decline with warming, releasing hosts from disease. Recently, changes in El Niño–Southern Oscillation events have had a detectable influence on marine and terrestrial pathogens, including coral diseases, oyster pathogens, crop pathogens, Rift Valley fever, and human cholera. To improve our ability to predict epidemics in wild populations, it will be necessary to separate the independent and interactive effects of multiple climate drivers on disease impact.

  15. Seventh Grade Students' Conceptions of Global Warming and Climate Change

    ERIC Educational Resources Information Center

    Shepardson, Daniel P.; Niyogi, Dev; Choi, Soyoung; Charusombat, Umarporn

    2009-01-01

    The purpose of this study was to investigate seventh grade students' conceptions of global warming and climate change. The study was descriptive in nature and involved the collection of qualitative data from 91 seventh grade students from three different schools in the Midwest, USA. An open response and draw and explain assessment instrument was…

  16. Impacts of climate warming on terrestrial ectotherms across latitude

    E-print Network

    Huey, Raymond B.

    Impacts of climate warming on terrestrial ectotherms across latitude Curtis A. Deutsch* , Joshua J for terrestrial ectotherms. Our analyses imply that, in the absence of ameliorating factors such as migration with the physiological sensitivity of organisms to that change (12). Ectotherms constitute the vast majority

  17. Warming Up the Classroom Climate for Women.

    ERIC Educational Resources Information Center

    Rosser, Sue V.

    1989-01-01

    Presents five exercises, based on the "Chilly Climate" papers, designed to enhance faculty and staff sensitivity to the need of providing a comfortable learning environment for women. Covers definition of sexism, pronouns as power, gender differences in experiences with sexism, incorporating feminist scholarship into traditional courses,…

  18. Climate Whiplash: What Happens AFTER Global Warming?

    E-print Network

    Mallin, Michael

    the next nation-crushing ice age. But as the Earth finally starts to cool down again, "climate whiplash" will force people, animals, and plants to reverse their adaptive strategies. Losers may then become winners in this new geologic epoch, the "Age of Humans." Curt Stager is a paleo-ecologist, award-winning educator

  19. Climate warming and Bergmann's rule through time: is there any evidence?

    PubMed Central

    Teplitsky, Celine; Millien, Virginie

    2014-01-01

    Climate change is expected to induce many ecological and evolutionary changes. Among these is the hypothesis that climate warming will cause a reduction in body size. This hypothesis stems from Bergmann's rule, a trend whereby species exhibit a smaller body size in warmer climates, and larger body size under colder conditions in endotherms. The mechanisms behind this rule are still debated, and it is not clear whether Bergmann's rule can be extended to predict the effects of climate change through time. We reviewed the primary literature for evidence (i) of a decrease in body size in response to climate warming, (ii) that changing body size is an adaptive response and (iii) that these responses are evolutionary or plastic. We found weak evidence for changes in body size through time as predicted by Bergmann's rule. Only three studies investigated the adaptive nature of these size decreases. Of these, none reported evidence of selection for smaller size or of a genetic basis for the size change, suggesting that size decreases could be due to nonadaptive plasticity in response to changing environmental conditions. More studies are needed before firm conclusions can be drawn about the underlying causes of these changes in body size in response to a warming climate. PMID:24454554

  20. Potential Distribution Predicted for Rhynchophorus ferrugineus in China under Different Climate Warming Scenarios.

    PubMed

    Ge, Xuezhen; He, Shanyong; Wang, Tao; Yan, Wei; Zong, Shixiang

    2015-01-01

    As the primary pest of palm trees, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) has caused serious harm to palms since it first invaded China. The present study used CLIMEX 1.1 to predict the potential distribution of R. ferrugineus in China according to both current climate data (1981-2010) and future climate warming estimates based on simulated climate data for the 2020s (2011-2040) provided by the Tyndall Center for Climate Change Research (TYN SC 2.0). Additionally, the Ecoclimatic Index (EI) values calculated for different climatic conditions (current and future, as simulated by the B2 scenario) were compared. Areas with a suitable climate for R. ferrugineus distribution were located primarily in central China according to the current climate data, with the northern boundary of the distribution reaching to 40.1°N and including Tibet, north Sichuan, central Shaanxi, south Shanxi, and east Hebei. There was little difference in the potential distribution predicted by the four emission scenarios according to future climate warming estimates. The primary prediction under future climate warming models was that, compared with the current climate model, the number of highly favorable habitats would increase significantly and expand into northern China, whereas the number of both favorable and marginally favorable habitats would decrease. Contrast analysis of EI values suggested that climate change and the density of site distribution were the main effectors of the changes in EI values. These results will help to improve control measures, prevent the spread of this pest, and revise the targeted quarantine areas. PMID:26496438

  1. Potential Distribution Predicted for Rhynchophorus ferrugineus in China under Different Climate Warming Scenarios

    PubMed Central

    Ge, Xuezhen; He, Shanyong; Wang, Tao; Yan, Wei; Zong, Shixiang

    2015-01-01

    As the primary pest of palm trees, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) has caused serious harm to palms since it first invaded China. The present study used CLIMEX 1.1 to predict the potential distribution of R. ferrugineus in China according to both current climate data (1981–2010) and future climate warming estimates based on simulated climate data for the 2020s (2011–2040) provided by the Tyndall Center for Climate Change Research (TYN SC 2.0). Additionally, the Ecoclimatic Index (EI) values calculated for different climatic conditions (current and future, as simulated by the B2 scenario) were compared. Areas with a suitable climate for R. ferrugineus distribution were located primarily in central China according to the current climate data, with the northern boundary of the distribution reaching to 40.1°N and including Tibet, north Sichuan, central Shaanxi, south Shanxi, and east Hebei. There was little difference in the potential distribution predicted by the four emission scenarios according to future climate warming estimates. The primary prediction under future climate warming models was that, compared with the current climate model, the number of highly favorable habitats would increase significantly and expand into northern China, whereas the number of both favorable and marginally favorable habitats would decrease. Contrast analysis of EI values suggested that climate change and the density of site distribution were the main effectors of the changes in EI values. These results will help to improve control measures, prevent the spread of this pest, and revise the targeted quarantine areas. PMID:26496438

  2. Climatic Conditions in Classrooms.

    ERIC Educational Resources Information Center

    Kevan, Simon M.; Howes, John D.

    1980-01-01

    Presents an overview of research on the ways in which classroom thermal environment, lighting conditions, ion state, and electromagnetic and air pollution affect learning and the performance of students and teachers. (SJL)

  3. Warming Experiments Underpredict Plant Phenological Responses to Climate Change

    NASA Technical Reports Server (NTRS)

    Wolkovich, E. M.; Cook, B. I.; Allen, J. M.; Crimmins, T. M.; Betancourt, J. L.; Travers, S. E.; Pau, S.; Regetz, J.; Davies, T. J.; Kraft, N. J. B.; Ault, T. R.; Bolmgren, K.; Mazer, S. J.; McCabe, G. J.; McGill, B. J.; Parmesan, C.; Salamin, N.; Schwartz, M. D.; Cleland, E. E.

    2012-01-01

    Warming experiments are increasingly relied on to estimate plant responses to global climate change. For experiments to provide meaningful predictions of future responses, they should reflect the empirical record of responses to temperature variability and recent warming, including advances in the timing of flowering and leafing. We compared phenology (the timing of recurring life history events) in observational studies and warming experiments spanning four continents and 1,634 plant species using a common measure of temperature sensitivity (change in days per degree Celsius). We show that warming experiments underpredict advances in the timing of flowering and leafing by 8.5-fold and 4.0-fold, respectively, compared with long-term observations. For species that were common to both study types, the experimental results did not match the observational data in sign or magnitude. The observational data also showed that species that flower earliest in the spring have the highest temperature sensitivities, but this trend was not reflected in the experimental data. These significant mismatches seem to be unrelated to the study length or to the degree of manipulated warming in experiments. The discrepancy between experiments and observations, however, could arise from complex interactions among multiple drivers in the observational data, or it could arise from remediable artefacts in the experiments that result in lower irradiance and drier soils, thus dampening the phenological responses to manipulated warming. Our results introduce uncertainty into ecosystem models that are informed solely by experiments and suggest that responses to climate change that are predicted using such models should be re-evaluated.

  4. Conservation Planning for Coral Reefs Accounting for Climate Warming Disturbances

    PubMed Central

    Magris, Rafael A.; Heron, Scott F.; Pressey, Robert L.

    2015-01-01

    Incorporating warming disturbances into the design of marine protected areas (MPAs) is fundamental to developing appropriate conservation actions that confer coral reef resilience. We propose an MPA design approach that includes spatially- and temporally-varying sea-surface temperature (SST) data, integrating both observed (1985–2009) and projected (2010–2099) time-series. We derived indices of acute (time under reduced ecosystem function following short-term events) and chronic thermal stress (rate of warming) and combined them to delineate thermal-stress regimes. Coral reefs located on the Brazilian coast were used as a case study because they are considered a conservation priority in the southwestern Atlantic Ocean. We show that all coral reef areas in Brazil have experienced and are projected to continue to experience chronic warming, while acute events are expected to increase in frequency and intensity. We formulated quantitative conservation objectives for regimes of thermal stress. Based on these objectives, we then evaluated if/how they are achieved in existing Brazilian MPAs and identified priority areas where additional protection would reinforce resilience. Our results show that, although the current system of MPAs incorporates locations within some of our thermal-stress regimes, historical and future thermal refugia along the central coast are completely unprotected. Our approach is applicable to other marine ecosystems and adds to previous marine planning for climate change in two ways: (i) by demonstrating how to spatially configure MPAs that meet conservation objectives for warming disturbance using spatially- and temporally-explicit data; and (ii) by strategically allocating different forms of spatial management (MPA types) intended to mitigate warming impacts and also enhance future resistance to climate warming. PMID:26535586

  5. Lungs in a warming world: climate change and respiratory health.

    PubMed

    Bernstein, Aaron S; Rice, Mary B

    2013-05-01

    Climate change is a health threat no less consequential than cigarette smoking. Increased concentrations of greenhouse gases, and especially CO?, in the earth's atmosphere have already warmed the planet substantially, causing more severe and prolonged heat waves, temperature variability, air pollution, forest fires, droughts, and floods, all of which put respiratory health at risk. These changes in climate and air quality substantially increase respiratory morbidity and mortality for patients with common chronic lung diseases such as asthma and COPD and other serious lung diseases. Physicians have a vital role in addressing climate change, just as they did with tobacco, by communicating how climate change is a serious, but remediable, hazard to their patients. PMID:23648909

  6. Simulated warm periods of climate over China during the last two millennia: The Sui-Tang warm period versus the Song-Yuan warm period

    NASA Astrophysics Data System (ADS)

    Yan, Qing; Zhang, Zhongshi; Wang, Huijun; Jiang, Dabang

    2015-03-01

    A 2000 year simulation forced by the external forcings of the last two millennia is carried out with the Community Earth System Model. We compare climate changes over China between the peak Sui-Tang warm period (Sui-TangWP; 650-700 A.D.) and Song-Yuan warm period (Song-YuanWP; 950-1000 A.D.), which were two key culturally, economically, and educationally prosperous eras in Chinese history. The simulation indicates warm conditions in both periods, but the warmth is mainly seen in East China in the peak Sui-TangWP, and over the whole of China in the peak Song-YuanWP. The warming in the peak Sui-TangWP is attributed to the localized increase of atmospheric net energy with favorable heat transport, whereas the peak Song-YuanWP results from the increase of global solar radiation. The annual mean precipitation anomalies in the peak Sui-TangWP exhibit a meridional dipole pattern over East China, with enhanced precipitation in the region south of the Yangtze River and decreased precipitation to the north. In the peak Song-YuanWP, the precipitation enhances over most parts of China. The precipitation anomalies are largely attributed to the water vapor transport anomalies associated with monsoon circulation changes. The simulated climate changes are broadly consistent with reconstructions, but the magnitude is greatly underestimated. Based on the simulation and reconstructions, we suggest that the Sui-TangWP may have been a regional phenomenon in China, while the Song-YuanWP was a reflection of global/hemispheric-scale warm events that took place at the same time.

  7. Climate extremes and ecosystem productivity in global warming simulations

    NASA Astrophysics Data System (ADS)

    Williams, I. N.; Torn, M. S.; Riley, W. J.; Wehner, M. F.; Collins, W.

    2013-12-01

    Ecosystem responses to present-day droughts and heat-waves are often considered indicative of future global warming impacts on ecosystems, under the assumption that the temperature above which vegetation experiences heat and drought stress is invariant with changes in climate and carbon dioxide concentration. Understanding how the impacts of temperature extremes on ecosystems can change with climate change is essential for correctly evaluating and developing Earth System Models (ESMs). The Coupled Model Inter-comparison Project (CMIP5) historical and future (RCP8.5) climate predictions were analyzed in this study to illustrate non-stationarity of climate impacts on ecosystems, as evident by changes in the distribution of Gross Primary Production (GPP) as a function of temperature between future and historical climates. These changes consist of (1) a uniform shift in the GPP distribution toward warmer temperatures between future and historical climates, and (2) a proportional increase in GPP at all temperatures, consistent with CO2 fertilization. The temperature at which GPP has a local maximum within a given climate increases with global warming and closely tracks the change in mean temperature for each ecosystem. This maximum GPP temperature can be conceptualized as a stable equilibrium determined by the temperature at which an increase in plant water stress is compensated by a decrease in light stress (decreasing cloud cover) with increasing temperature. Temperature relative to the temperature of maximum GPP is proposed as an improved measure of climate extremes more relevant to ecosystem productivity than absolute temperature. The percentage change in GPP attributed to changes in relative temperature extremes is up to 3% per K (decrease in GPP), and reflects both an increase in the frequency of climate extremes in global warming scenarios and the change in temperature criteria for negative climate impacts on ecosystem productivity. Temperature at GPP maximum as a function of the growing season average temperature, for each ecosystem type. Lengths of crosshairs indicate the standard error of the CMIP5 ensemble average. Both future and historical averages are shown (the temperature of GPP maximum increases monotonically with growing season average temperature between future and historical simulations).

  8. Reductions in labour capacity from heat stress under climate warming

    NASA Astrophysics Data System (ADS)

    Dunne, John P.; Stouffer, Ronald J.; John, Jasmin G.

    2013-06-01

    A fundamental aspect of greenhouse-gas-induced warming is a global-scale increase in absolute humidity. Under continued warming, this response has been shown to pose increasingly severe limitations on human activity in tropical and mid-latitudes during peak months of heat stress. One heat-stress metric with broad occupational health applications is wet-bulb globe temperature. We combine wet-bulb globe temperatures from global climate historical reanalysis and Earth System Model (ESM2M) projections with industrial and military guidelines for an acclimated individual's occupational capacity to safely perform sustained labour under environmental heat stress (labour capacity)--here defined as a global population-weighted metric temporally fixed at the 2010 distribution. We estimate that environmental heat stress has reduced labour capacity to 90% in peak months over the past few decades. ESM2M projects labour capacity reduction to 80% in peak months by 2050. Under the highest scenario considered (Representative Concentration Pathway 8.5), ESM2M projects labour capacity reduction to less than 40% by 2200 in peak months, with most tropical and mid-latitudes experiencing extreme climatological heat stress. Uncertainties and caveats associated with these projections include climate sensitivity, climate warming patterns, CO2 emissions, future population distributions, and technological and societal change.

  9. Data of high performance precast external walls for warm climate.

    PubMed

    Baglivo, Cristina; Maria Congedo, Paolo

    2015-09-01

    The data given in the following paper are related to input and output information of the paper entitled Design method of high performance precast external walls for warm climate by multi-objective optimization analysis by Baglivo et al. [1]. Previous studies demonstrate that the superficial mass and the internal areal heat capacity are necessary to reach the best performances for the envelope of the Zero Energy Buildings located in a warm climate [2-4]. The results show that it is possible to achieve high performance precast walls also with light and ultra-thin solutions. A multi-criteria optimization has been performed in terms of steady and dynamic thermal behavior, eco sustainability score and costs. The modeFRONTIER optimization tool, with the use of computational procedures developed in Matlab, has been used to assess the thermal dynamics of building components. A large set of the best configurations of precast external walls for warm climate with their physical and thermal properties have been reported in the data article. PMID:26306317

  10. Data of high performance precast external walls for warm climate?

    PubMed Central

    Baglivo, Cristina; Maria Congedo, Paolo

    2015-01-01

    The data given in the following paper are related to input and output information of the paper entitled Design method of high performance precast external walls for warm climate by multi-objective optimization analysis by Baglivo et al. [1]. Previous studies demonstrate that the superficial mass and the internal areal heat capacity are necessary to reach the best performances for the envelope of the Zero Energy Buildings located in a warm climate [2–4]. The results show that it is possible to achieve high performance precast walls also with light and ultra-thin solutions. A multi-criteria optimization has been performed in terms of steady and dynamic thermal behavior, eco sustainability score and costs. The modeFRONTIER optimization tool, with the use of computational procedures developed in Matlab, has been used to assess the thermal dynamics of building components. A large set of the best configurations of precast external walls for warm climate with their physical and thermal properties have been reported in the data article. PMID:26306317

  11. Predicted effects of climate warming on the distribution of 50 stream fishes in Wisconsin, U.S.A.

    USGS Publications Warehouse

    Stewart, Jana S.; John Lyons; Matt Mitro

    2010-01-01

    Summer air and stream water temperatures are expected to rise in the state of Wisconsin, U.S.A., over the next 50 years. To assess potential climate warming effects on stream fishes, predictive models were developed for 50 common fish species using classification-tree analysis of 69 environmental variables in a geographic information system. Model accuracy was 56·0–93·5% in validation tests. Models were applied to all 86 898 km of stream in the state under four different climate scenarios: current conditions, limited climate warming (summer air temperatures increase 1° C and water 0·8° C), moderate warming (air 3° C and water 2·4° C) and major warming (air 5° C and water 4° C). With climate warming, 23 fishes were predicted to decline in distribution (three to extirpation under the major warming scenario), 23 to increase and four to have no change. Overall, declining species lost substantially more stream length than increasing species gained. All three cold-water and 16 cool-water fishes and four of 31 warm-water fishes were predicted to decline, four warm-water fishes to remain the same and 23 warm-water fishes to increase in distribution. Species changes were predicted to be most dramatic in small streams in northern Wisconsin that currently have cold to cool summer water temperatures and are dominated by cold-water and cool-water fishes, and least in larger and warmer streams and rivers in southern Wisconsin that are currently dominated by warm-water fishes. Results of this study suggest that even small increases in summer air and water temperatures owing to climate warming will have major effects on the distribution of stream fishes in Wisconsin.

  12. Recent Antarctic Peninsula warming relative to Holocene climate and ice-shelf history.

    PubMed

    Mulvaney, Robert; Abram, Nerilie J; Hindmarsh, Richard C A; Arrowsmith, Carol; Fleet, Louise; Triest, Jack; Sime, Louise C; Alemany, Olivier; Foord, Susan

    2012-09-01

    Rapid warming over the past 50?years on the Antarctic Peninsula is associated with the collapse of a number of ice shelves and accelerating glacier mass loss. In contrast, warming has been comparatively modest over West Antarctica and significant changes have not been observed over most of East Antarctica, suggesting that the ice-core palaeoclimate records available from these areas may not be representative of the climate history of the Antarctic Peninsula. Here we show that the Antarctic Peninsula experienced an early-Holocene warm period followed by stable temperatures, from about 9,200 to 2,500?years ago, that were similar to modern-day levels. Our temperature estimates are based on an ice-core record of deuterium variations from James Ross Island, off the northeastern tip of the Antarctic Peninsula. We find that the late-Holocene development of ice shelves near James Ross Island was coincident with pronounced cooling from 2,500 to 600?years ago. This cooling was part of a millennial-scale climate excursion with opposing anomalies on the eastern and western sides of the Antarctic Peninsula. Although warming of the northeastern Antarctic Peninsula began around 600 years ago, the high rate of warming over the past century is unusual (but not unprecedented) in the context of natural climate variability over the past two millennia. The connection shown here between past temperature and ice-shelf stability suggests that warming for several centuries rendered ice shelves on the northeastern Antarctic Peninsula vulnerable to collapse. Continued warming to temperatures that now exceed the stable conditions of most of the Holocene epoch is likely to cause ice-shelf instability to encroach farther southward along the Antarctic Peninsula. PMID:22914090

  13. Estimating present climate in a warming world: a model-based approach

    SciTech Connect

    Raeisaenen, J.; Ruokolainen, L.

    2008-09-30

    Weather services base their operational definitions of 'present' climate on past observations, using a 30-year normal period such as 1961-1990 or 1971-2000. In a world with ongoing global warming, however, past data give a biased estimate of the actual present-day climate. Here we propose to correct this bias with a 'delta change' method, in which model-simulated climate changes and observed global mean temperature changes are used to extrapolate past observations forward in time, to make them representative of present or future climate conditions. In a hindcast test for the years 1991-2002, the method works well for temperature, with a clear improvement in verification statistics compared to the case in which the hindcast is formed directly from the observations for 1961-1990. However, no improvement is found for precipitation, for which the signal-to-noise ratio between expected anthropogenic changes and interannual variability is much lower than for temperature. An application of the method to the present (around the year 2007) climate suggests that, as a geographical average over land areas excluding Antarctica, 8-9 months per year and 8-9 years per decade can be expected to be warmer than the median for 1971-2000. Along with the overall warming, a substantial increase in the frequency of warm extremes at the expense of cold extremes of monthly-to-annual temperature is expected.

  14. DO GLOBAL WARMING AND CLIMATE CHANGE REPRESENT A SERIOUS THREAT TO OUR WELFARE

    E-print Network

    DO GLOBAL WARMING AND CLIMATE CHANGE REPRESENT A SERIOUS THREAT TO OUR WELFARE AND ENVIRONMENT? By Michael E. Mann I. Introduction The subjects of "global warming" and "climate change" have become parts of both the popular lexicon and the public discourse. Discussions of global warming often evoke passionate

  15. Climate changes mirror global warming predictions BY THOMAS CROWLEY Guest columnist

    E-print Network

    Climate changes mirror global warming predictions BY THOMAS CROWLEY Guest columnist The Herald" and must reflect, at least in part, the climate system response to the increase in global warming. What if we wanted to prevent global warming. This is just doomsday speaking of the same type that he

  16. Increased Climate Variability Is More Visible Than Global Warming: A General

    E-print Network

    Kreinovich, Vladik

    Increased Climate Variability Is More Visible Than Global Warming: A General System@utep.edu Abstract While global warming is a statistically confirmed long-term phenomenon, its most visible than the global warming itself. 1 Formulation of the Problem What is global warming. The term "global

  17. Political Polarization over Global Warming: Analyzing Twitter Data on Climate Change

    E-print Network

    Sukthankar, Gita Reese

    Political Polarization over Global Warming: Analyzing Twitter Data on Climate Change Alireza/Democrats are more likely to ex- press personal concern about global warming than are self-identified conservatives

  18. Multisectoral climate impact hotspots in a warming world.

    PubMed

    Piontek, Franziska; Müller, Christoph; Pugh, Thomas A M; Clark, Douglas B; Deryng, Delphine; Elliott, Joshua; Colón González, Felipe de Jesus; Flörke, Martina; Folberth, Christian; Franssen, Wietse; Frieler, Katja; Friend, Andrew D; Gosling, Simon N; Hemming, Deborah; Khabarov, Nikolay; Kim, Hyungjun; Lomas, Mark R; Masaki, Yoshimitsu; Mengel, Matthias; Morse, Andrew; Neumann, Kathleen; Nishina, Kazuya; Ostberg, Sebastian; Pavlick, Ryan; Ruane, Alex C; Schewe, Jacob; Schmid, Erwin; Stacke, Tobias; Tang, Qiuhong; Tessler, Zachary D; Tompkins, Adrian M; Warszawski, Lila; Wisser, Dominik; Schellnhuber, Hans Joachim

    2014-03-01

    The impacts of global climate change on different aspects of humanity's diverse life-support systems are complex and often difficult to predict. To facilitate policy decisions on mitigation and adaptation strategies, it is necessary to understand, quantify, and synthesize these climate-change impacts, taking into account their uncertainties. Crucial to these decisions is an understanding of how impacts in different sectors overlap, as overlapping impacts increase exposure, lead to interactions of impacts, and are likely to raise adaptation pressure. As a first step we develop herein a framework to study coinciding impacts and identify regional exposure hotspots. This framework can then be used as a starting point for regional case studies on vulnerability and multifaceted adaptation strategies. We consider impacts related to water, agriculture, ecosystems, and malaria at different levels of global warming. Multisectoral overlap starts to be seen robustly at a mean global warming of 3 °C above the 1980-2010 mean, with 11% of the world population subject to severe impacts in at least two of the four impact sectors at 4 °C. Despite these general conclusions, we find that uncertainty arising from the impact models is considerable, and larger than that from the climate models. In a low probability-high impact worst-case assessment, almost the whole inhabited world is at risk for multisectoral pressures. Hence, there is a pressing need for an increased research effort to develop a more comprehensive understanding of impacts, as well as for the development of policy measures under existing uncertainty. PMID:24344270

  19. Weakening of atmospheric information flow in a warming climate in the Community

    E-print Network

    Ebert-Uphoff, Imme

    Weakening of atmospheric information flow in a warming climate in the Community Climate System Model Yi Deng1 and Imme Ebert-Uphoff2 1 School of Earth and Atmospheric Sciences, Georgia Institute characteristics of atmospheric information flow in a warming climate. The key idea is to interpret large

  20. The effect of slope aspect on the response of snowpack to climate warming in the Pyrenees

    NASA Astrophysics Data System (ADS)

    López-Moreno, J. I.; Revuelto, J.; Gilaberte, M.; Morán-Tejeda, E.; Pons, M.; Jover, E.; Esteban, P.; García, C.; Pomeroy, J. W.

    2014-07-01

    The aim of this study was to analyse the effect of slope aspect on the response of snowpack to climate warming in the Pyrenees. For this purpose, data available from five automatic weather stations were used to simulate the energy and mass balance of snowpack, assuming different magnitudes of an idealized climate warming (upward shifting of 1, 2 and 3 °C the temperature series). Snow energy and mass balance were simulated using the Cold Regions Hydrological Modelling platform (CRHM). CRHM was used to create a model that enabled correction of the all-wave incoming radiation fluxes from the observation sites for various slope aspects (N, NE, E, SE, S, SW,W,NW and flat areas), which enabled assessment of the differential impact of climate warming on snow processes on mountain slopes. The results showed that slope aspect was responsible for substantial variability in snow accumulation and the duration of the snowpack. Simulated variability markedly increased with warmer temperature conditions. Annual maximum snow accumulation (MSA) and annual snowpack duration (ASD) showed marked sensitivity to a warming of 1 °C. Thus, the sensitivity of the MSA in flat areas ranged from 11 to 17 % per degree C amongst the weather stations, and the ASD ranged from 11 to 20 days per degree C. There was a clear increase in the sensitivity of the snowpack to climate warming on those slopes that received intense solar radiation (S, SE and SW slopes) compared with those slopes where the incident radiation was more limited (N, NE and NW slopes). The sensitivity of the MSA and the ASD increased as the temperature increased, particularly on the most irradiated slopes. Large interannual variability was also observed. Thus, with more snow accumulation and longer duration the sensitivity of the snowpack to temperature decreased, especially on south-facing slopes.

  1. Climate warming and agricultural stressors interact to determine stream periphyton community composition.

    PubMed

    Piggott, Jeremy J; Salis, Romana K; Lear, Gavin; Townsend, Colin R; Matthaei, Christoph D

    2015-01-01

    Lack of knowledge about how the various drivers of global climate change will interact with multiple stressors already affecting ecosystems is the basis for great uncertainty in projections of future biological change. Despite concerns about the impacts of changes in land use, eutrophication and climate warming in running waters, the interactive effects of these stressors on stream periphyton are largely unknown. We manipulated nutrients (simulating agricultural runoff), deposited fine sediment (simulating agricultural erosion) (two levels each) and water temperature (eight levels, 0-6 °C above ambient) simultaneously in 128 streamside mesocosms. Our aim was to determine the individual and combined effects of the three stressors on the algal and bacterial constituents of the periphyton. All three stressors had pervasive individual effects, but in combination frequently produced synergisms at the population level and antagonisms at the community level. Depending on sediment and nutrient conditions, the effect of raised temperature frequently produced contrasting response patterns, with stronger or opposing effects when one or both stressors were augmented. Thus, warming tended to interact negatively with nutrients or sediment by weakening or reversing positive temperature effects or strengthening negative ones. Five classes of algal growth morphology were all affected in complex ways by raised temperature, suggesting that these measures may prove unreliable in biomonitoring programs in a warming climate. The evenness and diversity of the most abundant bacterial taxa increased with temperature at ambient but not with enriched nutrient levels, indicating that warming coupled with nutrient limitation may lead to a more evenly distributed bacterial community as temperatures rise. Freshwater management decisions that seek to avoid or mitigate the negative effects of agricultural land use on stream periphyton should be informed by knowledge of the interactive effects of multiple stressors in a warming climate. PMID:24942814

  2. Trophic level responses differ as climate warms in Ireland.

    PubMed

    Donnelly, Alison; Yu, Rong; Liu, Lingling

    2015-08-01

    Effective ecosystem functioning relies on successful species interaction. However, this delicate balance may be disrupted if species do not respond to environmental change at a similar rate. Here we examine trends in the timing of spring phenophases of groups of species occupying three trophic levels as a potential indicator of ecosystem response to climate warming in Ireland. The data sets were of varying length (1976-2009) and from varying locations: (1) timing of leaf unfolding and May Shoot of a range of broadleaf and conifer tree species, (2) first appearance dates of a range of moth species, and (3) first arrival dates of a range of spring migrant birds. All three groups revealed a statistically significant (P<0.01 and P<0.001) advance in spring phenology that was driven by rising spring temperature (P<0.05; 0.45 °C /decade). However, the rate of advance was greater for moths (1.8 days/year), followed by birds (0.37 days/year) and trees (0.29 days/year). In addition, the length of time between (1) moth emergence and leaf unfolding and (2) moth emergence and bird arrival decreased significantly (P<0.05 and P<0.001, respectively), indicating a decrease in the timing between food supply and demand. These differing trophic level response rates demonstrate the potential for a mismatch in the timing of interdependent phenophases as temperatures rise. Even though these data were not specifically collected to examine climate warming impacts, we conclude that such data may be used as an early warning indicator and as a means to monitor the potential for future ecosystem disruption to occur as climate warms. PMID:25380974

  3. Measure Guideline: Supplemental Dehumidification in Warm-Humid Climates

    SciTech Connect

    Rudd, A.

    2014-10-01

    This document covers a description of the need and applied solutions for supplemental dehumidification in warm-humid climates, especially for energy efficient homes where the sensible cooling load has been dramatically reduced. In older homes in warm-humid climates, cooling loads are typically high and cooling equipment runs a lot to cool the air. The cooling process also removes indoor moisture, reducing indoor relative humidity. However, at current residential code levels, and especially for above-code programs, sensible cooling loads have been so dramatically reduced that the cooling system does not run a lot to cool the air, resulting in much less moisture being removed. In these new homes, cooling equipment is off for much longer periods of time especially during spring/fall seasons, summer shoulder months, rainy periods, some summer nights, and some winter days. In warm-humid climates, those long off periods allow indoor humidity to become elevated due to internally generated moisture and ventilation air change. Elevated indoor relative humidity impacts comfort, indoor air quality, and building material durability. Industry is responding with supplemental dehumidification options, but that effort is really in its infancy regarding year-round humidity control in low-energy homes. Available supplemental humidity control options are discussed. Some options are less expensive but may not control indoor humidity as well as more expensive and comprehensive options. The best performing option is one that avoids overcooling and avoids adding unnecessary heat to the space by using waste heat from the cooling system to reheat the cooled and dehumidified air to room-neutral temperature.

  4. Measure Guideline: Supplemental Dehumidification in Warm-Humid Climates

    SciTech Connect

    Rudd, Armin

    2014-10-01

    This document covers a description of the need and applied solutions for supplemental dehumidification in warm-humid climates, especially for energy efficient homes where the sensible cooling load has been dramatically reduced. Cooling loads are typically high and cooling equipment runs a lot to cool the air in older homes in warm-humid climates. The cooling process also removes indoor moisture, reducing indoor relative humidity. However, at current residential code levels, and especially for above-code programs, sensible cooling loads have been so dramatically reduced that the cooling system does not run a lot to cool the air, resulting in much less moisture being removed. In these new homes, cooling equipment is off for much longer periods of time especially during spring/fall seasons, summer shoulder months, rainy periods, some summer nights, and winter days. In warm-humid climates, those long-off periods allow indoor humidity to become elevated due to internally generated moisture and ventilation air change. Elevated indoor relative humidity impacts comfort, indoor air quality, and building material durability. Industry is responding with supplemental dehumidification options, but that effort is really in its infancy regarding year-round humidity control in low-energy homes. Available supplemental humidity control options are discussed. Some options are less expensive but may not control indoor humidity as well as more expensive and comprehensive options. The best performing option is one that avoids overcooling and adding unnecessary heat to the space by using waste heat from the cooling system to reheat the cooled and dehumidified air to room-neutral temperature.

  5. Trophic level responses differ as climate warms in Ireland

    NASA Astrophysics Data System (ADS)

    Donnelly, Alison; Yu, Rong; Liu, Lingling

    2015-08-01

    Effective ecosystem functioning relies on successful species interaction. However, this delicate balance may be disrupted if species do not respond to environmental change at a similar rate. Here we examine trends in the timing of spring phenophases of groups of species occupying three trophic levels as a potential indicator of ecosystem response to climate warming in Ireland. The data sets were of varying length (1976-2009) and from varying locations: (1) timing of leaf unfolding and May Shoot of a range of broadleaf and conifer tree species, (2) first appearance dates of a range of moth species, and (3) first arrival dates of a range of spring migrant birds. All three groups revealed a statistically significant ( P<0.01 and P<0.001) advance in spring phenology that was driven by rising spring temperature ( P<0.05; 0.45 °C /decade). However, the rate of advance was greater for moths (1.8 days/year), followed by birds (0.37 days/year) and trees (0.29 days/year). In addition, the length of time between (1) moth emergence and leaf unfolding and (2) moth emergence and bird arrival decreased significantly ( P<0.05 and P<0.001, respectively), indicating a decrease in the timing between food supply and demand. These differing trophic level response rates demonstrate the potential for a mismatch in the timing of interdependent phenophases as temperatures rise. Even though these data were not specifically collected to examine climate warming impacts, we conclude that such data may be used as an early warning indicator and as a means to monitor the potential for future ecosystem disruption to occur as climate warms.

  6. The impact of boreal forest fire on climate warming

    USGS Publications Warehouse

    Randerson, J.T.; Liu, H.; Flanner, M.G.; Chambers, S.D.; Jin, Y.; Hess, P.G.; Pfister, G.; Mack, M.C.; Treseder, K.K.; Welp, L.R.; Chapin, F.S.; Harden, J.W.; Goulden, M.L.; Lyons, E.; Neff, J.C.; Schuur, E.A.G.; Zender, C.S.

    2006-01-01

    We report measurements and analysis of a boreal forest fire, integrating the effects of greenhouse gases, aerosols, black carbon deposition on snow and sea ice, and postfire changes in surface albedo. The net effect of all agents was to increase radiative forcing during the first year (34 ?? 31 Watts per square meter of burned area), but to decrease radiative forcing when averaged over an 80-year fire cycle (-2.3 ?? 2.2 Watts per square meter) because multidecadal increases in surface albedo had a larger impact than fire-emitted greenhouse gases. This result implies that future increases in boreal fire may not accelerate climate warming.

  7. Warm-water coral reefs and climate change

    NASA Astrophysics Data System (ADS)

    Spalding, Mark D.; Brown, Barbara E.

    2015-11-01

    Coral reefs are highly dynamic ecosystems that are regularly exposed to natural perturbations. Human activities have increased the range, intensity, and frequency of disturbance to reefs. Threats such as overfishing and pollution are being compounded by climate change, notably warming and ocean acidification. Elevated temperatures are driving increasingly frequent bleaching events that can lead to the loss of both coral cover and reef structural complexity. There remains considerable variability in the distribution of threats and in the ability of reefs to survive or recover from such disturbances. Without significant emissions reductions, however, the future of coral reefs is increasingly bleak.

  8. Warm-water coral reefs and climate change.

    PubMed

    Spalding, Mark D; Brown, Barbara E

    2015-11-13

    Coral reefs are highly dynamic ecosystems that are regularly exposed to natural perturbations. Human activities have increased the range, intensity, and frequency of disturbance to reefs. Threats such as overfishing and pollution are being compounded by climate change, notably warming and ocean acidification. Elevated temperatures are driving increasingly frequent bleaching events that can lead to the loss of both coral cover and reef structural complexity. There remains considerable variability in the distribution of threats and in the ability of reefs to survive or recover from such disturbances. Without significant emissions reductions, however, the future of coral reefs is increasingly bleak. PMID:26564846

  9. Implications of global warming for the climate of African rainforests.

    PubMed

    James, Rachel; Washington, Richard; Rowell, David P

    2013-01-01

    African rainforests are likely to be vulnerable to changes in temperature and precipitation, yet there has been relatively little research to suggest how the regional climate might respond to global warming. This study presents projections of temperature and precipitation indices of relevance to African rainforests, using global climate model experiments to identify local change as a function of global temperature increase. A multi-model ensemble and two perturbed physics ensembles are used, one with over 100 members. In the east of the Congo Basin, most models (92%) show a wet signal, whereas in west equatorial Africa, the majority (73%) project an increase in dry season water deficits. This drying is amplified as global temperature increases, and in over half of coupled models by greater than 3% per °C of global warming. Analysis of atmospheric dynamics in a subset of models suggests that this could be partly because of a rearrangement of zonal circulation, with enhanced convection in the Indian Ocean and anomalous subsidence over west equatorial Africa, the Atlantic Ocean and, in some seasons, the Amazon Basin. Further research to assess the plausibility of this and other mechanisms is important, given the potential implications of drying in these rainforest regions. PMID:23878329

  10. Implications of global warming for the climate of African rainforests

    PubMed Central

    James, Rachel; Washington, Richard; Rowell, David P.

    2013-01-01

    African rainforests are likely to be vulnerable to changes in temperature and precipitation, yet there has been relatively little research to suggest how the regional climate might respond to global warming. This study presents projections of temperature and precipitation indices of relevance to African rainforests, using global climate model experiments to identify local change as a function of global temperature increase. A multi-model ensemble and two perturbed physics ensembles are used, one with over 100 members. In the east of the Congo Basin, most models (92%) show a wet signal, whereas in west equatorial Africa, the majority (73%) project an increase in dry season water deficits. This drying is amplified as global temperature increases, and in over half of coupled models by greater than 3% per °C of global warming. Analysis of atmospheric dynamics in a subset of models suggests that this could be partly because of a rearrangement of zonal circulation, with enhanced convection in the Indian Ocean and anomalous subsidence over west equatorial Africa, the Atlantic Ocean and, in some seasons, the Amazon Basin. Further research to assess the plausibility of this and other mechanisms is important, given the potential implications of drying in these rainforest regions. PMID:23878329

  11. NorTropical Warm Pool variability and its effects on the climate of Colombia

    NASA Astrophysics Data System (ADS)

    Ricaurte Villota, Constanza; Romero-Rodriguez, Deisy; Coca-Domínguez, Oswaldo

    2015-04-01

    Much has been said about the effects of El Niño Southern Oscillation (ENSO) on oceanographic and climatic conditions in Colombia, but little is known about the influence of the Atlantic Warm Pool (AWP), which includes the gulf of Mexico, the Caribbean and the western tropical North Atlantic. The AWP has been identified by some authors as an area that influences the Earth's climate, associated with anomalous summer rainfall and hurricane activity in the Atlantic. The aim of this study was to understand the variation in the AWP and its effects on the climate of Colombia. An annual average of sea surface temperature (SST) was obtained from the composition of monthly images of the Spectroradiometer Moderate Resolution Imaging Spectroradiometer (MODIS), with resolution of 4 km, for one area that comprises the marine territory of Colombia, Panama, Costa Rica both the Pacific and the Caribbean, and parts of the Caribbean coast of Nicaragua, for the period between 2007 and 2013. The results suggest that warm pool is not restricted to the Caribbean, but it also covers a strip Pacific bordering Central America and the northern part of the Colombian coast, so it should be called the Nor-Tropical Warm pool (NTWP). Within the NTWP higher SST correspond to a marine area extending about 1 degree north and south of Central and out of the Colombian Caribbean coast. The NTWP also showed large interannual variability, with the years 2008 and 2009 with lower SST in average, while 2010, 2011 and 2013 years with warmer conditions, matching with greater precipitation. It was also noted that during warmer conditions (high amplitude NTWP) the cold tongue from the south Pacific has less penetration on Colombian coast. Finally, the results suggest a strong influence of NTWP in climatic conditions in Colombia.

  12. Inconsistent Range Shifts within Species Highlight Idiosyncratic Responses to Climate Warming

    PubMed Central

    Gibson-Reinemer, Daniel K.; Rahel, Frank J.

    2015-01-01

    Climate in part determines species’ distributions, and species’ distributions are shifting in response to climate change. Strong correlations between the magnitude of temperature changes and the extent of range shifts point to warming temperatures as the single most influential factor causing shifts in species’ distributions species. However, other abiotic and biotic factors may alter or even reverse these patterns. The importance of temperature relative to these other factors can be evaluated by examining range shifts of the same species in different geographic areas. When the same species experience warming in different geographic areas, the extent to which they show range shifts that are similar in direction and magnitude is a measure of temperature’s importance. We analyzed published studies to identify species that have documented range shifts in separate areas. For 273 species of plants, birds, mammals, and marine invertebrates with range shifts measured in multiple geographic areas, 42-50% show inconsistency in the direction of their range shifts, despite experiencing similar warming trends. Inconsistency of within-species range shifts highlights how biotic interactions and local, non-thermal abiotic conditions may often supersede the direct physiological effects of temperature. Assemblages show consistent responses to climate change, but this predictability does not appear to extend to species considered individually. PMID:26162013

  13. Global Warming, Climate Change and Glacier Retreat of Nepal Himalayas

    NASA Astrophysics Data System (ADS)

    Shrestha, S.; Hisaki, Y.

    2007-12-01

    Global average air temperature near the earth surface rose 0.74¡¾0.18¨¬C during the twentieth century. The Intergovernmental Panel on Climate Change (IPCC) concludes that observed increased globally averaged temperatures since mid-twentieth century is very likely due to the observed increment in anthropogenic greenhouse gas concentrations, which leads to warming of the surface and lower atmosphere by increasing the greenhouse effect. Climate models referred by IPCC project that global surface temperature are likely to be increase by 1.1 to 6.4¨¬C between 1990 and 2100. An increase in global temperature is expected to cause other changes including glacier retreat, sea level rise, increase intensity of extreme weather events and change in the pattern of precipitation, etc. The Nepal Himalaya revealed 3,252 glaciers and 2,323 lakes, which are 3,500 m above the sea level. They cover an area of 5,323 km2 with an estimated ice reserve of 481 km3. The average temperature in Nepal is rising by 0.5¨¬C per decade, and because of this reason, big glacial lakes in the country are at high risk of flooding from glacial lake bursts, which would have an adverse effect, such as huge loss of life and property. Nepal is facing a disturbance in mountain climate, flash floods, cloudbursts, erratic weather patterns and so on. The death of number of people due to floods and landslides is increasing annually. It is reported that more than 164 people already died because of floods and landslides during the current year, 2007 rainy season. Nepal does emit negligible greenhouse gases compare to developed and industrialized countries, however, country and people are facing the consequences of actions of other developed and industrialized countries. Study shows the¡¡disasters in current years and possible hazards in future due to the probable causes of global warming and recommends some suggestions for controlling of green house gases emission.

  14. Multisectoral climate impact hotspots in a warming world

    PubMed Central

    Piontek, Franziska; Müller, Christoph; Pugh, Thomas A. M.; Clark, Douglas B.; Deryng, Delphine; Elliott, Joshua; Colón González, Felipe de Jesus; Flörke, Martina; Folberth, Christian; Franssen, Wietse; Frieler, Katja; Friend, Andrew D.; Gosling, Simon N.; Hemming, Deborah; Khabarov, Nikolay; Kim, Hyungjun; Lomas, Mark R.; Masaki, Yoshimitsu; Mengel, Matthias; Morse, Andrew; Neumann, Kathleen; Nishina, Kazuya; Ostberg, Sebastian; Pavlick, Ryan; Ruane, Alex C.; Schewe, Jacob; Schmid, Erwin; Stacke, Tobias; Tang, Qiuhong; Tessler, Zachary D.; Tompkins, Adrian M.; Warszawski, Lila; Wisser, Dominik; Schellnhuber, Hans Joachim

    2014-01-01

    The impacts of global climate change on different aspects of humanity’s diverse life-support systems are complex and often difficult to predict. To facilitate policy decisions on mitigation and adaptation strategies, it is necessary to understand, quantify, and synthesize these climate-change impacts, taking into account their uncertainties. Crucial to these decisions is an understanding of how impacts in different sectors overlap, as overlapping impacts increase exposure, lead to interactions of impacts, and are likely to raise adaptation pressure. As a first step we develop herein a framework to study coinciding impacts and identify regional exposure hotspots. This framework can then be used as a starting point for regional case studies on vulnerability and multifaceted adaptation strategies. We consider impacts related to water, agriculture, ecosystems, and malaria at different levels of global warming. Multisectoral overlap starts to be seen robustly at a mean global warming of 3 °C above the 1980–2010 mean, with 11% of the world population subject to severe impacts in at least two of the four impact sectors at 4 °C. Despite these general conclusions, we find that uncertainty arising from the impact models is considerable, and larger than that from the climate models. In a low probability-high impact worst-case assessment, almost the whole inhabited world is at risk for multisectoral pressures. Hence, there is a pressing need for an increased research effort to develop a more comprehensive understanding of impacts, as well as for the development of policy measures under existing uncertainty. PMID:24344270

  15. Multisectoral Climate Impact Hotspots in a Warming World

    NASA Technical Reports Server (NTRS)

    Piontek, Franziska; Mueller, Christoph; Pugh, Thomas A. M.; Clark, Douglas B.; Deryng, Delphine; Elliott, Joshua; deJesusColonGonzalez, Felipe; Floerke, Martina; Folberth, Christian; Franssen, Wietse; Frieler, Katja; Friend, Andrew D.; Gosling, Simon N.; Hemming, Deborah; Khabarov, Nikolay; Kim, Hyungjun; Lomas, Mark R.; Masaki, Yoshimitsu; Mengel, Matthias; Morse, Andrew; Neumann, Kathleen; Nishina, Kazuya; Ostberg, Sebastian; Pavlick, Ryan; Ruane, Alex C.

    2014-01-01

    The impacts of global climate change on different aspects of humanity's diverse life-support systems are complex and often difficult to predict. To facilitate policy decisions on mitigation and adaptation strategies, it is necessary to understand, quantify, and synthesize these climate-change impacts, taking into account their uncertainties. Crucial to these decisions is an understanding of how impacts in different sectors overlap, as overlapping impacts increase exposure, lead to interactions of impacts, and are likely to raise adaptation pressure. As a first step we develop herein a framework to study coinciding impacts and identify regional exposure hotspots. This framework can then be used as a starting point for regional case studies on vulnerability and multifaceted adaptation strategies. We consider impacts related to water, agriculture, ecosystems, and malaria at different levels of global warming. Multisectoral overlap starts to be seen robustly at a mean global warming of 3 degC above the 1980-2010 mean, with 11% of the world population subject to severe impacts in at least two of the four impact sectors at 4 degC. Despite these general conclusions, we find that uncertainty arising from the impact models is considerable, and larger than that from the climate models. In a low probability-high impact worst-case assessment, almost the whole inhabited world is at risk for multisectoral pressures. Hence, there is a pressing need for an increased research effort to develop a more comprehensive understanding of impacts, as well as for the development of policy measures under existing uncertainty.

  16. Aridity changes in the Tibetan Plateau in a warming climate

    DOE PAGESBeta

    Gao, Yanhong; Li, Xia; Leung, Lai-Yung R.; Chen, Deliang; Xu, Jianwei

    2015-03-10

    Desertification in the Tibetan Plateau (TP) has drawn increasing attention in the recent decades. It has been postulated as a consequence of climate aridity due to the observed warming. This study quantifies the aridity changes in the TP and attributes the changes to different climatic factors. Using the ratio of P/PET (precipitation to potential evapotranspiration) as an aridity index to indicate changes in dryness and wetness in a given area, P/PET was calculated using observed records at 83 stations in the TP, with PET calculated using the Penman–Monteith (PM) algorithm. Spatial and temporal changes of P/PET in 1979-2011 are analyzed.more »Results show that stations located in the arid and semi-arid northwestern TP are becoming significantly wetter and stations in the semi-humid southeastern TP are becoming drier, though not significantly, in the recent three decades. The aridity change patterns are significantly correlated with precipitation, sunshine duration and diurnal temperature range changes at confidence level of 99.9% from two-tail t-test. Temporal correlations also confirm the significant correlation between aridity changes with the three variables, with precipitation being the most dominant driver of P/PET changes at interannual time scale. PET changes are insignificant but negatively correlated with P/PET in the cold season. In the warm season, however, correlation between PET changes and P/PET changes are significant at confidence level of 99.9% when the cryosphere melts near the surface. Significant correlation between wind speed changes and aridity changes occurs in limited locations and months. Consistency in the climatology pattern and linear trends in surface air temperature and precipitation calculated using station data, gridded data, and nearest grid-to-stations for the TP average and across sub-basins indicate the robustness of the trends despite the large spatial heterogeneity in the TP that challenge climate monitoring.« less

  17. Aridity changes in the Tibetan Plateau in a warming climate

    SciTech Connect

    Gao, Yanhong; Li, Xia; Leung, Lai-Yung R.; Chen, Deliang; Xu, Jianwei

    2015-03-10

    Desertification in the Tibetan Plateau (TP) has drawn increasing attention in the recent decades. It has been postulated as a consequence of climate aridity due to the observed warming. This study quantifies the aridity changes in the TP and attributes the changes to different climatic factors. Using the ratio of P/PET (precipitation to potential evapotranspiration) as an aridity index to indicate changes in dryness and wetness in a given area, P/PET was calculated using observed records at 83 stations in the TP, with PET calculated using the Penman–Monteith (PM) algorithm. Spatial and temporal changes of P/PET in 1979-2011 are analyzed. Results show that stations located in the arid and semi-arid northwestern TP are becoming significantly wetter and stations in the semi-humid southeastern TP are becoming drier, though not significantly, in the recent three decades. The aridity change patterns are significantly correlated with precipitation, sunshine duration and diurnal temperature range changes at confidence level of 99.9% from two-tail t-test. Temporal correlations also confirm the significant correlation between aridity changes with the three variables, with precipitation being the most dominant driver of P/PET changes at interannual time scale. PET changes are insignificant but negatively correlated with P/PET in the cold season. In the warm season, however, correlation between PET changes and P/PET changes are significant at confidence level of 99.9% when the cryosphere melts near the surface. Significant correlation between wind speed changes and aridity changes occurs in limited locations and months. Consistency in the climatology pattern and linear trends in surface air temperature and precipitation calculated using station data, gridded data, and nearest grid-to-stations for the TP average and across sub-basins indicate the robustness of the trends despite the large spatial heterogeneity in the TP that challenge climate monitoring.

  18. Climate warming could shift the timing of seed germination in alpine plants

    PubMed Central

    Mondoni, Andrea; Rossi, Graziano; Orsenigo, Simone; Probert, Robin J.

    2012-01-01

    Background and Aims Despite the considerable number of studies on the impacts of climate change on alpine plants, there have been few attempts to investigate its effect on regeneration. Recruitment from seeds is a key event in the life-history of plants, affecting their spread and evolution and seasonal changes in climate will inevitably affect recruitment success. Here, an investigation was made of how climate change will affect the timing and the level of germination in eight alpine species of the glacier foreland. Methods Using a novel approach which considered the altitudinal variation of temperature as a surrogate for future climate scenarios, seeds were exposed to 12 different cycles of simulated seasonal temperatures in the laboratory, derived from measurements at the soil surface at the study site. Key Results Under present climatic conditions, germination occurred in spring, in all but one species, after seeds had experienced autumn and winter seasons. However, autumn warming resulted in a significant increase in germination in all but two species. In contrast, seed germination was less sensitive to changes in spring and/or winter temperatures, which affected only three species. Conclusions Climate warming will lead to a shift from spring to autumn emergence but the extent of this change across species will be driven by seed dormancy status. Ungerminated seeds at the end of autumn will be exposed to shorter winter seasons and lower spring temperatures in a future, warmer climate, but these changes will only have a minor impact on germination. The extent to which climate change will be detrimental to regeneration from seed is less likely to be due to a significant negative effect on germination per se, but rather to seedling emergence in seasons that the species are not adapted to experience. Emergence in autumn could have major implications for species currently adapted to emerge in spring. PMID:22596094

  19. Modeling Multi-Reservoir Hydropower Systems in the Sierra Nevada with Environmental Requirements and Climate Warming

    NASA Astrophysics Data System (ADS)

    Rheinheimer, David Emmanuel

    Hydropower systems and other river regulation often harm instream ecosystems, partly by altering the natural flow and temperature regimes that ecosystems have historically depended on. These effects are compounded at regional scales. As hydropower and ecosystems are increasingly valued globally due to growing values for clean energy and native species as well as and new threats from climate warming, it is important to understand how climate warming might affect these systems, to identify tradeoffs between different water uses for different climate conditions, and to identify promising water management solutions. This research uses traditional simulation and optimization to explore these issues in California's upper west slope Sierra Nevada mountains. The Sierra Nevada provides most of the water for California's vast water supply system, supporting high-elevation hydropower generation, ecosystems, recreation, and some local municipal and agricultural water supply along the way. However, regional climate warming is expected to reduce snowmelt and shift runoff to earlier in the year, affecting all water uses. This dissertation begins by reviewing important literature related to the broader motivations of this study, including river regulation, freshwater conservation, and climate change. It then describes three substantial studies. First, a weekly time step water resources management model spanning the Feather River watershed in the north to the Kern River watershed in the south is developed. The model, which uses the Water Evaluation And Planning System (WEAP), includes reservoirs, run-of-river hydropower, variable head hydropower, water supply demand, and instream flow requirements. The model is applied with a runoff dataset that considers regional air temperature increases of 0, 2, 4 and 6 °C to represent historical, near-term, mid-term and far-term (end-of-century) warming. Most major hydropower turbine flows are simulated well. Reservoir storage is also generally well simulated, mostly limited by the accuracy of inflow hydrology. System-wide hydropower generation is reduced by 9% with 6 °C warming. Most reductions in hydropower generation occur in the highly productive watersheds in the northern Sierra Nevada. The central Sierra Nevada sees less reduction in annual runoff and can adapt better to changes in runoff timing. Generation in southern watersheds is expected to decrease. System-wide, reservoirs adapt to capture earlier runoff, but mostly decrease in mean reservoir storage with warming due to decreasing annual runoff. Second, a multi-reservoir optimization model is developed using linear programming that considers the minimum instream flows (MIFs) and weekly down ramp rates (DRRs) in the Upper Yuba River in the northern Sierra Nevada. Weekly DRR constraints are used to mimic spring snowmelt flows, which are particularly important for downstream ecosystems in the Sierra Nevada but are currently missing due to the influence of dams. Trade-offs between MIFs, DRRs and hydropower are explored with air temperature warming (+0, 2, 4 and 6 °C). Under base case operations, mean annual hydropower generation increases slightly with 2 °C warming and decreases slightly with 6 °C warming. With 6 °C warming, the most ecologically beneficial MIF and DRR reduce hydropower generation 5.5% compared to base case operations and a historical climate, which has important implications for re-licensing the hydropower project. Finally, reservoir management for downstream temperatures is explored using a linear programming model to optimally release water from a reservoir using selective withdrawal. The objective function is to minimize deviations from desired downstream temperatures, which are specified to mimic the natural temperature regime in the river. One objective of this study was to develop a method that can be readily integrated into a basin-scale multi-reservoir optimization model using a network representation of system features. The second objective was to explore the potential use of reservoirs to maintain an ideal str

  20. Global warming and changes in risk of concurrent climate extremes: Insights from the 2014 California drought

    NASA Astrophysics Data System (ADS)

    AghaKouchak, Amir; Cheng, Linyin; Mazdiyasni, Omid; Farahmand, Alireza

    2014-12-01

    Global warming and the associated rise in extreme temperatures substantially increase the chance of concurrent droughts and heat waves. The 2014 California drought is an archetype of an event characterized by not only low precipitation but also extreme high temperatures. From the raging wildfires, to record low storage levels and snowpack conditions, the impacts of this event can be felt throughout California. Wintertime water shortages worry decision-makers the most because it is the season to build up water supplies for the rest of the year. Here we show that the traditional univariate risk assessment methods based on precipitation condition may substantially underestimate the risk of extreme events such as the 2014 California drought because of ignoring the effects of temperature. We argue that a multivariate viewpoint is necessary for assessing risk of extreme events, especially in a warming climate. This study discusses a methodology for assessing the risk of concurrent extremes such as droughts and extreme temperatures.

  1. Changes in tropical circulation in a warming climate

    NASA Astrophysics Data System (ADS)

    Chou, C.

    2013-12-01

    Precipitation is experiencing a great change under global warming. Two major processes induced changes in precipitation are thermodynamic and dynamic contributions. The former is related to changes in water vapor and the latter is associated with changes in vertical velocity. Since water vapor increases almost everywhere, the thermodynamic contribution is determined by the corresponding mean vertical motion: positive for ascents and negative for descents, which creates a 'wet-get-wetter and dry-get-drier' tendency. The dynamic contribution, on the other hand, is much more complicated, especially on a regional basis. For a global average, all climate models in the CMIP3 and CMIP5 show a robust weakening of tropical circulation, while observed changes in tropical circulation are inconsistent among data sets. A fundamental explanation for changes in tropical circulation is related to atmospheric stability. In a warmer climate, the upper troposphere warms up faster than the lower troposphere, so dry static stability increases. Thus, the atmosphere should become more stable and the corresponding tropical circulation weakens. However, a more physically-sound index, moist static stability, shows very scattering changes in global-warming simulations. In other words, the atmosphere can become either more stable or more unstable if considering the effect of water vapor. Here we introduce a new effect associated with convection depth by proposing another index, gross moist stability, to measure changes in atmospheric stability under global warming. The gross moist stability, an effective static stability, is vertical integral of the vertical gradient of moist static energy weighted by pressure velocity. It depends not only on the vertical gradient of dry static energy, which is equivalent to dry static stability, but also on moisture vertical distribution and convection depth. The effects of dry static energy and convection depth stabilize the atmosphere, while the moisture effect tends to destabilize the atmosphere. Because tropical convection closely follows a moist adiabatic process, there is a strong cancellation between the effects of dry static energy and moisture. This leads to the dominance of the effect of convection depth in atmospheric stability.

  2. Impacts of climate warming on vegetation in Qaidam Area from 1990 to 2003.

    PubMed

    Zeng, Biao; Yang, Tai-Bao

    2008-09-01

    The observed warming trend in the Qaidam area, an arid basin surrounded by high mountains, has caused land surface dynamics that are detectable using remotely sensed data. In this paper, we detected land-cover changes in the Qaidam Area between 1990 and 2003 in attempt to depict its spatial variability. The land-cover changes were categorized into two trends: degradation and amelioration, and their spatial patterns were examined. Then we estimated the correlation coefficients between growing-season NDVI and several climatic factors with the consideration of duration and lagging effects. The results show that the inter-annual NDVI variations are positively correlated with May to July precipitations, but not significantly correlated with sunshine duration. We observed no obvious trend in precipitation or sunshine duration from 1990 to 2003. Thus, the authors suggest that their slight fluctuations may not be responsible to the decade-scaled land-cover changes. However, our results indicate a good positive relationship between the NDVI trend and climate warming in the ameliorated areas, but a negative one in the degraded areas. By statistical analyses, we found that degradations mainly occurred at the oasis boundaries and at lower elevations in the non-oasis regions where effective soil moisture might have been reduced by the warming-caused increase in evapotranspiration. At higher elevations where thermal condition acts as a major limiting factor, ameliorations were unequivocally detected, which is attributable to the direct facilitation by temperature increases. We suggest that the impacts of the observed climate warming on vegetation are spatially heterogeneous, depending on the combinations of thermal condition and moisture availability. PMID:17965943

  3. An update on human-induced climate change: global warming: coming, ready or not.

    E-print Network

    Trenberth, Kevin Edward

    1 An update on human-induced climate change: global warming: coming, ready or not. Dr. Kevin E activity. There is no doubt that carbon dioxide is a greenhouse gas and causes warming, and it has a long significantly to warming, while aerosols and dust more often cause cooling and regionalize some of the radiative

  4. A Vast Machine Computer Models, Climate Data, and the Politics of Global Warming

    E-print Network

    Edwards, Paul N.

    A Vast Machine Computer Models, Climate Data, and the Politics of Global Warming Paul N. Edwards models, climate data, and the politics of global warming / Paul N. Edwards. p. cm. Includes bibliographical references and index. ISBN 978-0-262-01392-5 (hardcover : alk. paper) 1. Weather forecasting. 2

  5. The case for a wet, warm climate on early Mars

    NASA Technical Reports Server (NTRS)

    Pollack, J. B.; Kasting, J. F.; Richardson, S. M.; Poliakoff, K.

    1987-01-01

    Arguments are presented in support of the idea that Mars possessed a dense CO2 atmosphere and a wet, warm climate early in its history. The plausibility of a CO2 greenhouse is tested by formulating a simple model of the CO2 geochemical cycle on early Mars. By scaling the rate of silicate weathering on Earth, researchers estimated a weathering time constant of the order of several times 10 to the 7th power years for early Mars. Thus, a dense atmosphere could have existed for a geologically significant time period (approx. 10 to the 9th power years) only if atmospheric CO2 was being continuously resupplied. The most likely mechanism by which this could have been accomplished is the thermal decomposition of carbonate rocks induced directly or indirectly by intense, global scale volcanism.

  6. Unexpected response of high Alpine Lake waters to climate warming.

    PubMed

    Thies, Hansjörg; Nickus, Ulrike; Mair, Volkmar; Tessadri, Richard; Tait, Danilo; Thaler, Bertha; Psenner, Roland

    2007-11-01

    Over the past two decades, we have observed a substantial rise in solute concentration at two remote high mountain lakes in catchments of metamorphic rocks in the European Alps. At Rasass See, the electrical conductivity increased 18-fold. Unexpectedly high nickel concentrations at Rasass See, which exceeded the limit in drinking water by more than 1 order of magnitude, cannot be related to catchment geology. We attribute these changes in lake water quality to solute release from the ice of an active rock glacier in the catchment as a response to climate warming. Similar processes occurred at the higher elevation lake Schwarzsee ob Sölden, where electrical conductivity has risen 3-fold during the past two decades. PMID:18044521

  7. Declining ocean anoxia in a warming climate (Invited)

    NASA Astrophysics Data System (ADS)

    Deutsch, C. A.; Ito, T.; van Geen, A.; Berelson, W.; Thunell, R.

    2013-12-01

    The warming of Earth's climate is expected to lead to a loss of oceanic dissolved oxygen, an important constraint on marine species habitat. The mechanisms underlying this so-called deoxygenation are that dissolved gases are less soluble in warmer waters, and the rate at which O2-rich surface water is circulated into the low-O2 interior ocean is also reduced due to increased thermal stratification. Here we show that a robust prediction of state-of-the-art Earth System Models is that in the oxygen minimum zone of the tropical thermocline, oxygen concentrations are relatively stable or even increasing in a warming climate. The tropical immunity to deoxygenation arises because the lower solubility of O2 is closely compensated by a reduced upwelling at the equator, which slows the rate of biological productivity at the surface and the bacterial oxygen demand in deeper waters. The reduction of nutrient supply to the surface ocean is driven not by stratification but by a weakening of the tropical trade winds. However it can also be viewed as a necessary consequence of the reduced ventilation in mid-latitudes, arising from the conservation of mass and the close coupling of nutrient and oxygen cycles. On centennial time scales, these dynamics are predicted to lead to a reduction of anoxia in the ocean, even while oxygen is steadily declining globally. Evidence from sediment cores along the North American margin suggest a gradual reduction in 20th century denitrification, and support the wind-driven mechanism predicted by Earth System Models.

  8. Evaluation of Laboratory Conditioning Protocols for Warm-Mix Asphalt 

    E-print Network

    Yin, Fan 1990-

    2012-10-26

    : Chair of Committee, Amy Epps Martin Committee Members, Robert Lytton Charles Glover Head of Department, John Niedzwecki December 2012 Major Subject: Civil Engineering Copyright 2012 Fan Yin ii ABSTRACT Warm-Mix Asphalt (WMA) refers... as indicated by HWTT agree with those in a dry condition in MR testing. iv ACKNOWLEDGEMENTS Firstly, I must give my high, respectful gratitude to my committee chair, Dr. Amy Epps Martin, for her great assistance in helping me with my thesis. I...

  9. Total environmental warming impact (TEWI) calculations for alternative automative air-conditioning systems

    SciTech Connect

    Sand, J.R.; Fischer, S.K.

    1997-01-01

    The Montreal Protocol phase-out of chlorofluorocarbons (CFCs) has required manufacturers to develop refrigeration and air-conditioning systems that use refrigerants that can not damage stratospheric ozone. Most refrigeration industries have adapted their designs to use hydrochlorofluorocarbon (HCFC) or hydrofluorocarbon (HFC) refrigerants; new automobile air- conditioning systems use HFC-134a. These industries are now being affected by scientific investigations of greenhouse warming and questions about the effects of refrigerants on global warming. Automobile air-conditioning has three separate impacts on global warming; (1) the effects of refrigerant inadvertently released to the atmosphere from accidents, servicing, and leakage; (2) the efficiency of the cooling equipment (due to the emission of C0{sub 2} from burning fuel to power the system); and (3) the emission of C0{sub 2} from burning fuel to transport the system. The Total Equivalent Warming Impact (TEWI) is an index that should be used to compare the global warming effects of alternative air-conditioning systems because it includes these contributions from the refrigerant, cooling efficiency, and weight. This paper compares the TEWI of current air-conditioning systems using HFC-134a with that of transcritical vapor compression system using carbon dioxide and systems using flammable refrigerants with secondary heat transfer loops. Results are found to depend on both climate and projected efficiency of C0{sub 2}systems. Performance data on manufacturing prototype systems are needed to verify the potential reductions in TEWI. Extensive field testing is also required to determine the performance, reliability, and ``serviceability`` of each alternative to HFC-134a to establish whether the potential reduction of TEWI can be achieved in a viable consumer product.

  10. Darcy's law predicts widespread forest mortality under climate warming

    NASA Astrophysics Data System (ADS)

    McDowell, Nathan G.; Allen, Craig D.

    2015-07-01

    Drought and heat-induced tree mortality is accelerating in many forest biomes as a consequence of a warming climate, resulting in a threat to global forests unlike any in recorded history. Forests store the majority of terrestrial carbon, thus their loss may have significant and sustained impacts on the global carbon cycle. We use a hydraulic corollary to Darcy’s law, a core principle of vascular plant physiology, to predict characteristics of plants that will survive and die during drought under warmer future climates. Plants that are tall with isohydric stomatal regulation, low hydraulic conductance, and high leaf area are most likely to die from future drought stress. Thus, tall trees of old-growth forests are at the greatest risk of loss, which has ominous implications for terrestrial carbon storage. This application of Darcy’s law indicates today’s forests generally should be replaced by shorter and more xeric plants, owing to future warmer droughts and associated wildfires and pest attacks. The Darcy’s corollary also provides a simple, robust framework for informing forest management interventions needed to promote the survival of current forests. Given the robustness of Darcy’s law for predictions of vascular plant function, we conclude with high certainty that today’s forests are going to be subject to continued increases in mortality rates that will result in substantial reorganization of their structure and carbon storage.

  11. Climate warming and estuarine and marine coastal ecosystems

    SciTech Connect

    Kennedy, V.S.

    1994-12-31

    Estuaries are physically controlled, resilient coastal ecosystems harboring environmentally tolerant species in diluted seawater. Marine coastal systems are less stressed physically and contain some environmentally less tolerant species. Both systems are biologically productive and economically significant. Because of their complex structure and function, it is difficult to predict accurately the effects of climate change, but some broad generalizations can be made. If climate warming occurs, it will raise sea-level, heat shallow waters, and modify precipitation, wind, and water circulation patterns. Rapid sea-level rise could cause the loss of salt marshes, mangrove swamps, and coral reefs, thus diminishing the ecological roles of these highly productive systems. Warmer waters could eliminate heat-sensitive species from part of their geographical range while allowing heat-tolerant species to expand their range, depending on their ability to disperse. Most thermally influenced losses of species will probably only be local, but changed distributions may lead to changed community function. It is more difficult to predict the effects of modified precipitation, wind, and water circulation patterns, but changes could affect organisms dependent on such patterns for food production (e.g., in upwelling regions) or for retention in estuaries. Aquacultural and fishery-related enterprises would be affected negatively in some regions and positively in others. 73 refs.

  12. Oceanic oxygen in a warming climate: mechanisms, patterns, and timescales

    NASA Astrophysics Data System (ADS)

    Deutsch, C. A.; van Geen, A.; Berelson, W.; Ito, T.; Weber, T.

    2014-12-01

    The oxygenation of the ocean reflects a balance of physical O2 supply and biological O2 demand, both of which are strongly influenced by climate. The processes governing changes in O2 supply and demand are spatially heterogeneous and involve multiple time scales, leading to complex pattern of O2 variability. We present an analysis of model simulations, historical observations, and the recent sedimentary record that reveal fundamental differences between the O2 response of the tropics and high latitudes to rising greenhouse gases. Whereas the reduction in O2 solubility and a slowing of ocean circulation act in concert to deoxygenate the mid- and high-latitudes, these processes tend to counteract one another in the tropics. Emerging evidence from the sedimentary record and model reconstructions in the Pacific Ocean indicates that oxygen demand is the dominant control on oxygenation in the eastern tropical anoxic zones on decadal to centennial time scales. This reduction is closely linked to the strength of the tropical trade winds and upwelling, providing a mechanism for transient contraction of anoxia during climate warming.

  13. How much do precipitation extremes change in a warming climate?

    NASA Astrophysics Data System (ADS)

    Shiu, Chein-Jung; Liu, Shaw Chen; Fu, Congbin; Dai, Aiguo; Sun, Ying

    2012-09-01

    Daily data from reanalyses of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Centers for Environmental Prediction (NCEP) are analyzed to study changes in precipitation intensity with respect to global mean temperature. The results are in good agreement with those derived from the Global Precipitation Climatology Project (GPCP) data by Liu et al. (2009), providing an independent verification for large changes in the precipitation extremes: about 100% increase for the annual top 10% heavy precipitation and about 20% decrease for the light and moderate precipitation for one degree warming in the global temperature. These changes can substantially increase the risk of floods as well as droughts, thus severely affecting the global ecosystems. Atmospheric models used in the reanalysis mode, with the benefit of observed wind and moisture fields, appear to be capable of realistically simulating the change of precipitation intensity with global temperature. In comparison, coupled climate models are capable of simulating the shape of the change in precipitation intensity, but underestimate the magnitude of the change by about one order of magnitude. The most likely reason of the underestimation is that the typical spatial resolution of climate models is too coarse to resolve atmospheric convection.

  14. An unexpected role for mixotrophs in the response of peatland carbon cycling to climate warming

    PubMed Central

    Jassey, Vincent E. J.; Signarbieux, Constant; Hättenschwiler, Stephan; Bragazza, Luca; Buttler, Alexandre; Delarue, Frédéric; Fournier, Bertrand; Gilbert, Daniel; Laggoun-Défarge, Fatima; Lara, Enrique; T. E. Mills, Robert; Mitchell, Edward A. D.; Payne, Richard J.; Robroek, Bjorn J. M.

    2015-01-01

    Mixotrophic protists are increasingly recognized for their significant contribution to carbon (C) cycling. As phototrophs they contribute to photosynthetic C fixation, whilst as predators of decomposers, they indirectly influence organic matter decomposition. Despite these direct and indirect effects on the C cycle, little is known about the responses of peatland mixotrophs to climate change and the potential consequences for the peatland C cycle. With a combination of field and microcosm experiments, we show that mixotrophs in the Sphagnum bryosphere play an important role in modulating peatland C cycle responses to experimental warming. We found that five years of consecutive summer warming with peaks of +2 to +8°C led to a 50% reduction in the biomass of the dominant mixotrophs, the mixotrophic testate amoebae (MTA). The biomass of other microbial groups (including decomposers) did not change, suggesting MTA to be particularly sensitive to temperature. In a microcosm experiment under controlled conditions, we then manipulated the abundance of MTA, and showed that the reported 50% reduction of MTA biomass in the field was linked to a significant reduction of net C uptake (-13%) of the entire Sphagnum bryosphere. Our findings suggest that reduced abundance of MTA with climate warming could lead to reduced peatland C fixation. PMID:26603894

  15. An unexpected role for mixotrophs in the response of peatland carbon cycling to climate warming.

    PubMed

    Jassey, Vincent E J; Signarbieux, Constant; Hättenschwiler, Stephan; Bragazza, Luca; Buttler, Alexandre; Delarue, Frédéric; Fournier, Bertrand; Gilbert, Daniel; Laggoun-Défarge, Fatima; Lara, Enrique; T E Mills, Robert; Mitchell, Edward A D; Payne, Richard J; Robroek, Bjorn J M

    2015-01-01

    Mixotrophic protists are increasingly recognized for their significant contribution to carbon (C) cycling. As phototrophs they contribute to photosynthetic C fixation, whilst as predators of decomposers, they indirectly influence organic matter decomposition. Despite these direct and indirect effects on the C cycle, little is known about the responses of peatland mixotrophs to climate change and the potential consequences for the peatland C cycle. With a combination of field and microcosm experiments, we show that mixotrophs in the Sphagnum bryosphere play an important role in modulating peatland C cycle responses to experimental warming. We found that five years of consecutive summer warming with peaks of +2 to +8°C led to a 50% reduction in the biomass of the dominant mixotrophs, the mixotrophic testate amoebae (MTA). The biomass of other microbial groups (including decomposers) did not change, suggesting MTA to be particularly sensitive to temperature. In a microcosm experiment under controlled conditions, we then manipulated the abundance of MTA, and showed that the reported 50% reduction of MTA biomass in the field was linked to a significant reduction of net C uptake (-13%) of the entire Sphagnum bryosphere. Our findings suggest that reduced abundance of MTA with climate warming could lead to reduced peatland C fixation. PMID:26603894

  16. Climate Control Load Reduction Strategies for Electric Drive Vehicles in Warm Weather

    SciTech Connect

    Jeffers, M. A.; Chaney, L.; Rugh, J. P.

    2015-04-30

    Passenger compartment climate control is one of the largest auxiliary loads on a vehicle. Like conventional vehicles, electric vehicles (EVs) require climate control to maintain occupant comfort and safety, but cabin heating and air conditioning have a negative impact on driving range for all electric vehicles. Range reduction caused by climate control and other factors is a barrier to widespread adoption of EVs. Reducing the thermal loads on the climate control system will extend driving range, thereby reducing consumer range anxiety and increasing the market penetration of EVs. Researchers at the National Renewable Energy Laboratory have investigated strategies for vehicle climate control load reduction, with special attention toward EVs. Outdoor vehicle thermal testing was conducted on two 2012 Ford Focus Electric vehicles to evaluate thermal management strategies for warm weather, including solar load reduction and cabin pre-ventilation. An advanced thermal test manikin was used to assess a zonal approach to climate control. In addition, vehicle thermal analysis was used to support testing by exploring thermal load reduction strategies, evaluating occupant thermal comfort, and calculating EV range impacts. Through stationary cooling tests and vehicle simulations, a zonal cooling configuration demonstrated range improvement of 6%-15%, depending on the drive cycle. A combined cooling configuration that incorporated thermal load reduction and zonal cooling strategies showed up to 33% improvement in EV range.

  17. DOI 10.1007/s00382-015-2811-y Global and regional surface cooling in a warming climate: a

    E-print Network

    Drange, Helge

    1 3 DOI 10.1007/s00382-015-2811-y Clim Dyn Global and regional surface cooling in a warming climate surface temperature. The likelihood of decadal-scale non-warming periods decrease with global warming in a warming world. Keywords Hiatus · CMIP5 · Global warming · Decadal variability 1 Motivation A central issue

  18. Activity restriction and the mechanistic basis for extinctions under climate warming.

    PubMed

    R Kearney, Michael

    2013-12-01

    Correlative analyses predict that anthropogenic climate warming will cause widespread extinction but the nature and generality of the underlying mechanisms is unclear. Warming-induced activity restriction has been proposed as a general explanatory mechanism for recent population extinctions in lizards, and has been used to forecast future extinction. Here, I test this hypothesis using globally applied biophysical calculations of the effects of warming and shade reduction on potential activity time and whole-life-cycle energy budgets. These 'thermodynamic niche' analyses show that activity restriction from climate warming is unlikely to provide a general explanation of recent extinctions, and that loss of shade is viable alternative explanation. Climate warming could cause population declines, even under increased activity potential, through joint impacts on fecundity and mortality rates. However, such responses depend strongly on behaviour, habitat (shade, food) and life history, all of which should be explicitly incorporated in mechanistic forecasts of extinction risk under climate change. PMID:24118740

  19. A warming climate may result in increased morbidity and mortality related to ozone, an

    E-print Network

    a changing climate (Kinney et al., in press). Warming of 1.4­3.6°C (2.6­6.5°F) by the 2050s has been of hun- dreds of kilometers. Several past studies have assessed health impacts of climate change using by 2050 (Anderson HR et al. 2001). To better assess localized impacts of climate change, models are needed

  20. A Vast Machine Computer Models, Climate Data, and the Politics of Global Warming

    E-print Network

    Edwards, Paul N.

    In the countless political controver- sies over climate change, the debate often shakes out into a contest: models such thing as a pure climate simulation. Yes, we get a lot of knowledge from simulation models. But this bookA Vast Machine Computer Models, Climate Data, and the Politics of Global Warming Paul N. Edwards

  1. The warming climate could put food supplies at risk over the next decade or two.

    E-print Network

    Floeter, Sergio Ricardo

    ) and wheat growing under natural climate variations to projected yields influenced by human-induced climate change. The results suggest that with climate warming, the risk of losing 10% or more of the global wheat in certain cancer genes. The researchers also tested the cells' sensitivity to various drugs. With further

  2. Climate warming will reduce growth and survival of Scots pine except in the far north

    E-print Network

    Thomas, David D.

    LETTER Climate warming will reduce growth and survival of Scots pine except in the far north P. B in North America. Growth and survival were analysed in response to climatic transfer distance populations at each site, and across sites for regional groups of populations, were related to climate

  3. Comparison of "warm and wet" and "cold and icy" scenarios for early Mars in a 3D climate model

    E-print Network

    Wordsworth, Robin D; Pierrehumbert, Raymond T; Forget, Francois; Head, James W

    2015-01-01

    We use a 3D general circulation model to compare the primitive Martian hydrological cycle in "warm and wet" and "cold and icy" scenarios. In the warm and wet scenario, an anomalously high solar flux or intense greenhouse warming artificially added to the climate model are required to maintain warm conditions and an ice-free northern ocean. Precipitation shows strong surface variations, with high rates around Hellas basin and west of Tharsis but low rates around Margaritifer Sinus (where the observed valley network drainage density is nonetheless high). In the cold and icy scenario, snow migration is a function of both obliquity and surface pressure, and limited episodic melting is possible through combinations of seasonal, volcanic and impact forcing. At surface pressures above those required to avoid atmospheric collapse (~0.5 bar) and moderate to high obliquity, snow is transported to the equatorial highland regions where the concentration of valley networks is highest. Snow accumulation in the Aeolis quadr...

  4. Present weather and climate: evolving conditions

    USGS Publications Warehouse

    Hoerling, Martin P; Dettinger, Michael; Wolter, Klaus; Lukas, Jeff; Eischeid, Jon K.; Nemani, Rama; Liebmann, Brant; Kunkel, Kenneth E.

    2013-01-01

    This chapter assesses weather and climate variability and trends in the Southwest, using observed climate and paleoclimate records. It analyzes the last 100 years of climate variability in comparison to the last 1,000 years, and links the important features of evolving climate conditions to river flow variability in four of the region’s major drainage basins. The chapter closes with an assessment of the monitoring and scientific research needed to increase confidence in understanding when climate episodes, events, and phenomena are attributable to human-caused climate change.

  5. Linking climate change and biological invasions: Ocean warming facilitates nonindigenous

    E-print Network

    Stachowicz, Jay

    , and increasing the magnitude of their growth and recruitment relative to natives, global warming may facilitate warming on the time scale of decades also may alter the composition of the resident biota by facilitating, 18), global warming may relax this constraint. Despite consid- erable interest in predicting

  6. Enhanced Climatic Warming Over the Tibetan Plateau Due to Doubling CO2: A Model Study

    NASA Technical Reports Server (NTRS)

    Chen, Baode; Chao, Winston C.; Liu, Xiaodong; Lau, William K. M. (Technical Monitor)

    2001-01-01

    A number of studies have presented the evidences that surface climate change associated with global warming at high elevation sites shows more pronounced warming than at low elevations, i.e. an elevation dependency of climatic warming pointed out that snow-albedo feedback may be responsible for the excessive warming in the Swiss Alps. From an ensemble of climate change experiments of increasing greenhouse gases and aerosols using an air-sea coupled climate model, Eyre and Raw (1999) found a marked elevation dependency of the simulated surface screen temperature increase over the Rocky Mountains. Using almost all available instrumental records, Liu and Chen (2000) showed that the main portion of the Tibetan Plateau (TP) has experienced significant ground temperature warming since the middlebrows, especially in winter, and that there is a tendency for the warming trend to increase with elevation in the TP as well as its surrounding areas. In this paper, we will investigate the mechanism of elevation dependency of climatic warming in the TP by using a high-resolution regional climate model.

  7. Using Long-Term Experimental Warming To Distinguish Vegetation Responses To Warming From Other Environmental Drivers Related To Climate Change

    NASA Astrophysics Data System (ADS)

    Gould, W. A.; Welker, J. M.; Mercado-Díaz, J. A.; Anderson, A.; Menken, M.

    2010-12-01

    Long term studies of vegetation change throughout the tundra biome show increases in the height, canopy extent and dominance of vascular vegetation versus bryophytes and lichens, with mixed responses of the dominant shrub and graminoid growth forms. Increases in vascular vegetation are recorded for sites with and without measurable climatic warming over recent decades, but with other potential drivers, i.e., increased summer precipitation. Experimental warming of tundra vegetation at Toolik Lake, Alaska shows a clear increase in shrub abundance relative to graminoids, with correlated higher NDVI values, increasing canopy heights, and thaw depths. Responses were similar between moist and dry tundra vegetation, with greater responses in moist vegetation. NDVI, with its ability to distinguish shrub from graminoid vegetation, may be a tool to distinguish fine scale differences in the response of tundra vegetation to climatic change, i.e., shifting balances of shrub and graminoid relative abundances that may be related to distinct climatic change drivers.

  8. Climate-induced changes in carbon and nitrogen cycling in the rapidly warming Antarctic coastal ocean 

    E-print Network

    Henley, Sian Frances

    2013-07-01

    The western Antarctic Peninsula (WAP) is a hotspot of climatic and oceanographic change, with a 6°C rise in winter atmospheric temperatures and >1°C warming of the surface ocean since the 1950s. These trends are having ...

  9. Permafrost, Lakes, and Climate-Warming Methane Feedback: What is the Worst

    E-print Network

    when weighed against unconstrained human emissions. The additional warming from these methane sourcesPermafrost, Lakes, and Climate-Warming Methane Feedback: What is the Worst We Can Expect? Xiang Gao No. 218 May 2012 #12;The MIT Joint Program on the Science and Policy of Global Change

  10. Global and Regional Climate Response to Late Twentieth-Century Warming over the Indian Ocean

    E-print Network

    England, Matthew

    Global and Regional Climate Response to Late Twentieth-Century Warming over the Indian Ocean JAMES changes occur over the Indian Ocean, where the increase in tropical SST is found to drive enhanced convection throughout the troposphere. In the extratropics, the warming Indian Ocean is found to induce

  11. Antarctic ice-sheet melting provides negative feedbacks on future climate warming

    E-print Network

    Huybrechts, Philippe

    Antarctic ice-sheet melting provides negative feedbacks on future climate warming D. Swingedouw,1 T to millennial time scales Antarctic Ice Sheet (AIS) can melt and moderate warming in the Southern Hemisphere. Fichefet, P. Huybrechts, H. Goosse, E. Driesschaert, and M.-F. Loutre (2008), Antarctic ice-sheet melting

  12. 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.

  13. Increased evapotranspiration demand in a Mediterranean climate might cause a decline in fungal yields under global warming.

    PubMed

    Ágreda, Teresa; Águeda, Beatriz; Olano, José M; Vicente-Serrano, Sergio M; Fernández-Toirán, Marina

    2015-09-01

    Wild fungi play a critical role in forest ecosystems, and its recollection is a relevant economic activity. Understanding fungal response to climate is necessary in order to predict future fungal production in Mediterranean forests under climate change scenarios. We used a 15-year data set to model the relationship between climate and epigeous fungal abundance and productivity, for mycorrhizal and saprotrophic guilds in a Mediterranean pine forest. The obtained models were used to predict fungal productivity for the 2021-2080 period by means of regional climate change models. Simple models based on early spring temperature and summer-autumn rainfall could provide accurate estimates for fungal abundance and productivity. Models including rainfall and climatic water balance showed similar results and explanatory power for the analyzed 15-year period. However, their predictions for the 2021-2080 period diverged. Rainfall-based models predicted a maintenance of fungal yield, whereas water balance-based models predicted a steady decrease of fungal productivity under a global warming scenario. Under Mediterranean conditions fungi responded to weather conditions in two distinct periods: early spring and late summer-autumn, suggesting a bimodal pattern of growth. Saprotrophic and mycorrhizal fungi showed differences in the climatic control. Increased atmospheric evaporative demand due to global warming might lead to a drop in fungal yields during the 21st century. PMID:25930066

  14. Contribution of air conditioning adoption to future energy use under global warming

    PubMed Central

    Davis, Lucas W.; Gertler, Paul J.

    2015-01-01

    As household incomes rise around the world and global temperatures go up, the use of air conditioning is poised to increase dramatically. Air conditioning growth is expected to be particularly strong in middle-income countries, but direct empirical evidence is scarce. In this paper we use high-quality microdata from Mexico to describe the relationship between temperature, income, and air conditioning. We describe both how electricity consumption increases with temperature given current levels of air conditioning, and how climate and income drive air conditioning adoption decisions. We then combine these estimates with predicted end-of-century temperature changes to forecast future energy consumption. Under conservative assumptions about household income, our model predicts near-universal saturation of air conditioning in all warm areas within just a few decades. Temperature increases contribute to this surge in adoption, but income growth by itself explains most of the increase. What this will mean for electricity consumption and carbon dioxide emissions depends on the pace of technological change. Continued advances in energy efficiency or the development of new cooling technologies could reduce the energy consumption impacts. Similarly, growth in low-carbon electricity generation could mitigate the increases in carbon dioxide emissions. However, the paper illustrates the enormous potential impacts in this sector, highlighting the importance of future research on adaptation and underscoring the urgent need for global action on climate change. PMID:25918391

  15. Contribution of air conditioning adoption to future energy use under global warming.

    PubMed

    Davis, Lucas W; Gertler, Paul J

    2015-05-12

    As household incomes rise around the world and global temperatures go up, the use of air conditioning is poised to increase dramatically. Air conditioning growth is expected to be particularly strong in middle-income countries, but direct empirical evidence is scarce. In this paper we use high-quality microdata from Mexico to describe the relationship between temperature, income, and air conditioning. We describe both how electricity consumption increases with temperature given current levels of air conditioning, and how climate and income drive air conditioning adoption decisions. We then combine these estimates with predicted end-of-century temperature changes to forecast future energy consumption. Under conservative assumptions about household income, our model predicts near-universal saturation of air conditioning in all warm areas within just a few decades. Temperature increases contribute to this surge in adoption, but income growth by itself explains most of the increase. What this will mean for electricity consumption and carbon dioxide emissions depends on the pace of technological change. Continued advances in energy efficiency or the development of new cooling technologies could reduce the energy consumption impacts. Similarly, growth in low-carbon electricity generation could mitigate the increases in carbon dioxide emissions. However, the paper illustrates the enormous potential impacts in this sector, highlighting the importance of future research on adaptation and underscoring the urgent need for global action on climate change. PMID:25918391

  16. Responses of alpine grassland on Qinghai-Tibetan plateau to climate warming and permafrost degradation: a modeling perspective

    NASA Astrophysics Data System (ADS)

    Yi, Shuhua; Wang, Xiaoyun; Qin, Yu; Xiang, Bo; Ding, Yongjian

    2014-07-01

    Permafrost plays a critical role in soil hydrology. Thus, the degradation of permafrost under warming climate conditions may affect the alpine grassland ecosystem on the Qinghai-Tibetan Plateau. Previous space-for-time studies using plot and basin scales have reached contradictory conclusions. In this study, we applied a process-based ecosystem model (DOS-TEM) with a state-of-the-art permafrost hydrology scheme to examine this issue. Our results showed that 1) the DOS-TEM model could properly simulate the responses of soil thermal and hydrological dynamics and of ecosystem dynamics to climate warming and spatial differences in precipitation; 2) the simulated results were consistent with plot-scale studies showing that warming caused an increase in maximum unfrozen thickness, a reduction in vegetation and soil carbon pools as a whole, and decreases in soil water content, net primary production, and heterotrophic respiration; and 3) the simulated results were also consistent with basin-scale studies showing that the ecosystem responses to warming were different in regions with different combinations of water and energy constraints. Permafrost prevents water from draining into water reservoirs. However, the degradation of permafrost in response to warming is a long-term process that also enhances evapotranspiration. Thus, the degradation of the alpine grassland ecosystem on the Qinghai-Tibetan Plateau (releasing carbon) cannot be mainly attributed to the disappearing waterproofing function of permafrost.

  17. Allocation trade-off under climate warming in experimental amphibian populations.

    PubMed

    Gao, Xu; Jin, Changnan; Camargo, Arley; Li, Yiming

    2015-01-01

    Climate change could either directly or indirectly cause population declines via altered temperature, rainfall regimes, food availability or phenological responses. However few studies have focused on allocation trade-offs between growth and reproduction under marginal resources, such as food scarce that may be caused by climate warming. Such critical changes may have an unpredicted impact on amphibian life-history parameters and even population dynamics. Here, we report an allocation strategy of adult anuran individuals involving a reproductive stage under experimental warming. Using outdoor mesocosm experiments we simulated a warming scenario likely to occur at the end of this century. We examined the effects of temperature (ambient vs. pre-/post-hibernation warming) and food availability (normal vs. low) on reproduction and growth parameters of pond frogs (Pelophylax nigromaculatus). We found that temperature was the major factor influencing reproductive time of female pond frogs, which showed a significant advancing under post-hibernation warming treatment. While feeding rate was the major factor influencing reproductive status of females, clutch size, and variation of body size for females, showed significant positive correlations between feeding rate and reproductive status, clutch size, or variation of body size. Our results suggested that reproduction and body size of amphibians might be modulated by climate warming or food availability variation. We believe this study provides some new evidence on allocation strategies suggesting that amphibians could adjust their reproductive output to cope with climate warming. PMID:26500832

  18. Allocation trade-off under climate warming in experimental amphibian populations

    PubMed Central

    Gao, Xu; Jin, Changnan; Camargo, Arley

    2015-01-01

    Climate change could either directly or indirectly cause population declines via altered temperature, rainfall regimes, food availability or phenological responses. However few studies have focused on allocation trade-offs between growth and reproduction under marginal resources, such as food scarce that may be caused by climate warming. Such critical changes may have an unpredicted impact on amphibian life-history parameters and even population dynamics. Here, we report an allocation strategy of adult anuran individuals involving a reproductive stage under experimental warming. Using outdoor mesocosm experiments we simulated a warming scenario likely to occur at the end of this century. We examined the effects of temperature (ambient vs. pre-/post-hibernation warming) and food availability (normal vs. low) on reproduction and growth parameters of pond frogs (Pelophylax nigromaculatus). We found that temperature was the major factor influencing reproductive time of female pond frogs, which showed a significant advancing under post-hibernation warming treatment. While feeding rate was the major factor influencing reproductive status of females, clutch size, and variation of body size for females, showed significant positive correlations between feeding rate and reproductive status, clutch size, or variation of body size. Our results suggested that reproduction and body size of amphibians might be modulated by climate warming or food availability variation. We believe this study provides some new evidence on allocation strategies suggesting that amphibians could adjust their reproductive output to cope with climate warming. PMID:26500832

  19. Tropical Climate Mean State and Variability during the Pliocene Warm Period (Invited)

    NASA Astrophysics Data System (ADS)

    Ravelo, A. C.; Ford, H. L.; Dekens, P. S.; White, S. M.; Griffith, E. M.

    2013-12-01

    Past studies have shown that the mean climate state during the Pliocene warm period, about 3 - 4 million years ago, differed from present day climate in several ways: global temperature was about 3-4 degrees C warmer, the tropical thermocline was warmer and/or deeper, and meridional and zonal sea surface temperature gradients were reduced due to warmer high latitude temperatures but tropical sea surface temperatures that were similar to today. One of the most striking features of the Pliocene warm period is the El Niño-like (El Padre) mean state of the tropical Pacific, which is thought to have far-field impacts. In this study, we present a synthesis of new and published tropical Pacific data, detailing the mean state and higher frequency variability (e.g., using orbital scale records and measurements made on single foraminifera shells), for the purpose of meeting two main goals. First, we highlight important characteristics of the El Padre mean state, which include average Indo-Pacific warm pool temperatures that were similar and east Pacific cold tongue temperatures and cross-Pacific subsurface temperatures that were warmer than today. Because much of the paleotemperature data comes from Mg/Ca ratios measured in planktonic foraminifera, the impact of possible changes in Mg/Ca of seawater on paleotemperature estimates is addressed. We conclude that Mg/Ca-derived temperature estimates could be adjusted by no more than about 1 degree in order to account for seawater chemistry changes. Second, by examining orbital variability and temperature distributions based on single foraminifera analyses, we evaluate whether the cumulative strength of the many feedbacks that are involved in the generation of climate variability may be impacted by the mean state. Data indicate that the amplitude of orbital variability in surface temperature, and possibly the amplitude of ENSO variability, was reduced during the warm Pliocene compared to today. On orbital timescales, the reduction in the amplitude of variability could be explained by a possible reduction in orbital variations in CO2 forcing; this inference is supported by the single foraminiferal shell analyses from the west Pacific that show that the distribution of temperatures across seasons remained unchanged even as the mean temperature varied. On shorter, ENSO timescales, variability may have been affected by mean state conditions such as the reduced zonal gradient and the deeper/warmer thermocline that determine the strength of dominant feedbacks. In sum, while the mean state was radically different with reduced zonal gradients characteristic of El Padre, significant orbital, ENSO and seasonal variability was present, albeit reduced in amplitude in several datasets.

  20. Warm climate isotopic simulations: what do we learn about interglacial signals in Greenland ice cores?

    NASA Astrophysics Data System (ADS)

    Sime, Louise C.; Risi, Camille; Tindall, Julia C.; Sjolte, Jesper; Wolff, Eric W.; Masson-Delmotte, Valérie; Capron, Emilie

    2013-05-01

    Measurements of Last Interglacial stable water isotopes in ice cores show that central Greenland ?18O increased by at least 3‰ compared to present day. Attempting to quantify the Greenland interglacial temperature change from these ice core measurements rests on our ability to interpret the stable water isotope content of Greenland snow. Current orbitally driven interglacial simulations do not show ?18O or temperature rises of the correct magnitude, leading to difficulty in using only these experiments to inform our understanding of higher interglacial ?18O. Here, analysis of greenhouse gas warmed simulations from two isotope-enabled general circulation models, in conjunction with a set of Last Interglacial sea surface observations, indicates a possible explanation for the interglacial ?18O rise. A reduction in the winter time sea ice concentration around the northern half of Greenland, together with an increase in sea surface temperatures over the same region, is found to be sufficient to drive a >3‰ interglacial enrichment in central Greenland snow. Warm climate ?18O and ?D in precipitation falling on Greenland are shown to be strongly influenced by local sea surface condition changes: local sea surface warming and a shrunken sea ice extent increase the proportion of water vapour from local (isotopically enriched) sources, compared to that from distal (isotopically depleted) sources. Precipitation intermittency changes, under warmer conditions, leads to geographical variability in the ?18O against temperature gradients across Greenland. Little sea surface warming around the northern areas of Greenland leads to low ?18O against temperature gradients (0.1-0.3‰ per °C), whilst large sea surface warmings in these regions leads to higher gradients (0.3-0.7‰ per °C). These gradients imply a wide possible range of present day to interglacial temperature increases (4 to >10 °C). Thus, we find that uncertainty about local interglacial sea surface conditions, rather than precipitation intermittency changes, may lead to the largest uncertainties in interpreting temperature from Greenland ice cores. We find that interglacial sea surface change observational records are currently insufficient to enable discrimination between these different ?18O against temperature gradients. In conclusion, further information on interglacial sea surface temperatures and sea ice changes around northern Greenland should indicate whether +5 °C during the Last Interglacial is sufficient to drive the observed ice core ?18O increase, or whether a larger temperature increases or ice sheet changes are also required to explain the ice core observations.

  1. Impact of land surface processes on the South American warm season climate

    E-print Network

    Xue, Yongkang

    Impact of land surface processes on the South American warm season climate H.-Y. Ma · C. R. Mechoso season (December­ February) climate by an atmospheric general circulation model (AGCM) is sensitive transports abundant moisture from the Amazon basin to high latitudes, and in the monsoon region where

  2. Geoengineering of climate warming TR 2:55-4:10 Bradfield 1102

    E-print Network

    Mahowald, Natalie

    Geoengineering of climate warming TR 2:55-4:10 Bradfield 1102 Prerequisites: Math 1920 Geoengineering: the deliberate large-scale manipulation of the planetary environment to counteract anthropogenic strategies to geoengineer the climate (e.g., using balloon technology to emit reflecting sulfate aerosols

  3. Medical Providers as Global Warming and Climate Change Health Educators: A Health Literacy Approach

    ERIC Educational Resources Information Center

    Villagran, Melinda; Weathers, Melinda; Keefe, Brian; Sparks, Lisa

    2010-01-01

    Climate change is a threat to wildlife and the environment, but it also one of the most pervasive threats to human health. The goal of this study was to examine the relationships among dimensions of health literacy, patient education about global warming and climate change (GWCC), and health behaviors. Results reveal that patients who have higher…

  4. Does the climate warming hiatus exist over the Tibetan Plateau?

    PubMed

    Duan, Anmin; Xiao, Zhixiang

    2015-01-01

    The surface air temperature change over the Tibetan Plateau is determined based on historical observations from 1980 to 2013. In contrast to the cooling trend in the rest of China, and the global warming hiatus post-1990s, an accelerated warming trend has appeared over the Tibetan Plateau during 1998-2013 (0.25?°C decade(-1)), compared with that during 1980-1997 (0.21?°C decade(-1)). Further results indicate that, to some degree, such an accelerated warming trend might be attributable to cloud-radiation feedback. The increased nocturnal cloud over the northern Tibetan Plateau would warm the nighttime temperature via enhanced atmospheric back-radiation, while the decreased daytime cloud over the southern Tibetan Plateau would induce the daytime sunshine duration to increase, resulting in surface air temperature warming. Meanwhile, the in situ surface wind speed has recovered gradually since 1998, and thus the energy concentration cannot explain the accelerated warming trend over the Tibetan Plateau after the 1990s. It is suggested that cloud-radiation feedback may play an important role in modulating the recent accelerated warming trend over the Tibetan Plateau. PMID:26329678

  5. Does the climate warming hiatus exist over the Tibetan Plateau?

    PubMed Central

    Duan, Anmin; Xiao, Zhixiang

    2015-01-01

    The surface air temperature change over the Tibetan Plateau is determined based on historical observations from 1980 to 2013. In contrast to the cooling trend in the rest of China, and the global warming hiatus post-1990s, an accelerated warming trend has appeared over the Tibetan Plateau during 1998–2013 (0.25?°C decade?1), compared with that during 1980–1997 (0.21?°C decade?1). Further results indicate that, to some degree, such an accelerated warming trend might be attributable to cloud–radiation feedback. The increased nocturnal cloud over the northern Tibetan Plateau would warm the nighttime temperature via enhanced atmospheric back-radiation, while the decreased daytime cloud over the southern Tibetan Plateau would induce the daytime sunshine duration to increase, resulting in surface air temperature warming. Meanwhile, the in situ surface wind speed has recovered gradually since 1998, and thus the energy concentration cannot explain the accelerated warming trend over the Tibetan Plateau after the 1990s. It is suggested that cloud–radiation feedback may play an important role in modulating the recent accelerated warming trend over the Tibetan Plateau. PMID:26329678

  6. Does the climate warming hiatus exist over the Tibetan Plateau?

    NASA Astrophysics Data System (ADS)

    Duan, Anmin; Xiao, Zhixiang

    2015-09-01

    The surface air temperature change over the Tibetan Plateau is determined based on historical observations from 1980 to 2013. In contrast to the cooling trend in the rest of China, and the global warming hiatus post-1990s, an accelerated warming trend has appeared over the Tibetan Plateau during 1998-2013 (0.25?°C decade-1), compared with that during 1980-1997 (0.21?°C decade-1). Further results indicate that, to some degree, such an accelerated warming trend might be attributable to cloud-radiation feedback. The increased nocturnal cloud over the northern Tibetan Plateau would warm the nighttime temperature via enhanced atmospheric back-radiation, while the decreased daytime cloud over the southern Tibetan Plateau would induce the daytime sunshine duration to increase, resulting in surface air temperature warming. Meanwhile, the in situ surface wind speed has recovered gradually since 1998, and thus the energy concentration cannot explain the accelerated warming trend over the Tibetan Plateau after the 1990s. It is suggested that cloud-radiation feedback may play an important role in modulating the recent accelerated warming trend over the Tibetan Plateau.

  7. A volcanically induced climate warming and floral change preceded the onset of OAE1a (Early Cretaceous)

    E-print Network

    Gilli, Adrian

    A volcanically induced climate warming and floral change preceded the onset of OAE1a (Early change Climate change Early Cretaceous Negative carbon isotope excursion OAE1a Ontong Java volcanism volcanism are proposed as triggers for climate warming, altered ocean circulation patterns and elevated

  8. Species traits and climate velocity explain geographic range shifts in an ocean-warming hotspot.

    PubMed

    Sunday, Jennifer M; Pecl, Gretta T; Frusher, Stewart; Hobday, Alistair J; Hill, Nicole; Holbrook, Neil J; Edgar, Graham J; Stuart-Smith, Rick; Barrett, Neville; Wernberg, Thomas; Watson, Reg A; Smale, Dan A; Fulton, Elizabeth A; Slawinski, Dirk; Feng, Ming; Radford, Ben T; Thompson, Peter A; Bates, Amanda E

    2015-09-01

    Species' ranges are shifting globally in response to climate warming, with substantial variability among taxa, even within regions. Relationships between range dynamics and intrinsic species traits may be particularly apparent in the ocean, where temperature more directly shapes species' distributions. Here, we test for a role of species traits and climate velocity in driving range extensions in the ocean-warming hotspot of southeast Australia. Climate velocity explained some variation in range shifts, however, including species traits more than doubled the variation explained. Swimming ability, omnivory and latitudinal range size all had positive relationships with range extension rate, supporting hypotheses that increased dispersal capacity and ecological generalism promote extensions. We find independent support for the hypothesis that species with narrow latitudinal ranges are limited by factors other than climate. Our findings suggest that small-ranging species are in double jeopardy, with limited ability to escape warming and greater intrinsic vulnerability to stochastic disturbances. PMID:26189556

  9. Global warming: Growing feedback from ocean carbon to climate

    NASA Astrophysics Data System (ADS)

    Joos, Fortunat

    2015-06-01

    The finding that feedbacks between the ocean's carbon cycle and climate may become larger than terrestrial carbon-climate feedbacks has implications for the socio-economic effects of today's fossil-fuel emissions.

  10. Peculiarities of the dynamics of the general atmospheric circulation in conditions of the global climate change

    NASA Astrophysics Data System (ADS)

    Martynova, Yu. V.; Krupchatnikov, V. N.

    2015-05-01

    In the last decades, poleward displacements of elements of the general atmospheric circulation such as the Hadley Cell and storm tracks have been observed. On the basis of results of the numerical modeling of climate dynamics using an idealized model of the climatic system, we showed that the tendency to the displacement of storm tracks to the poles in the Northern Hemisphere would continue under the conditions of climate warming (according to the RCP 8.5 scenario). We also discuss the other peculiarities of the dynamics of the general circulation under the conditions of variable climate, which were revealed in the numerical experiment.

  11. Climate-change impact potentials as an alternative to global warming potentials

    NASA Astrophysics Data System (ADS)

    Kirschbaum, Miko U. F.

    2014-03-01

    For policy applications, such as for the Kyoto Protocol, the climate-change contributions of different greenhouse gases are usually quantified through their global warming potentials. They are calculated based on the cumulative radiative forcing resulting from a pulse emission of a gas over a specified time period. However, these calculations are not explicitly linked to an assessment of ultimate climate-change impacts. A new metric, the climate-change impact potential (CCIP), is presented here that is based on explicitly defining the climate-change perturbations that lead to three different kinds of climate-change impacts. These kinds of impacts are: (1) those related directly to temperature increases; (2) those related to the rate of warming; and (3) those related to cumulative warming. From those definitions, a quantitative assessment of the importance of pulse emissions of each gas is developed, with each kind of impact assigned equal weight for an overall impact assessment. Total impacts are calculated under the RCP6 concentration pathway as a base case. The relevant climate-change impact potentials are then calculated as the marginal increase of those impacts over 100 years through the emission of an additional unit of each gas in 2010. These calculations are demonstrated for CO2, methane and nitrous oxide. Compared with global warming potentials, climate-change impact potentials would increase the importance of pulse emissions of long-lived nitrous oxide and reduce the importance of short-lived methane.

  12. Expanding Peatlands in Alaska Caused by Accelerated Glacier Melting Under a Warming Climate

    NASA Astrophysics Data System (ADS)

    Loisel, J.; Yu, Z.; Jones, M. C.

    2009-05-01

    Most mountain glaciers worldwide have been retreating over the last century due to global warming. This is particularly true around the Gulf of Alaska, where glacier recession has further accelerated since 1988. It is well known that glacier meltwater plays a critical role in the global sea level rise, but its effects on structure and functioning of peatland ecosystems remain poorly understood. We have observed in the field that many peatlands in the Susitna Basin, south-central Alaska, are expanding. As high moisture conditions are needed to promote peatland development and expansion, a regional change toward wetter conditions is likely responsible for the ongoing paludification of these peatlands. However, instrumental climatic data from this region show no increase in precipitation but an increase in temperature (and presumably evaporation) over the last decades. We hypothesize that climatically-induced glacier melting is modifying the local/regional climate, especially air humidity during the growing season, promoting the expansion of peatlands. To document recent peatland vertical growth and lateral expansion, we collected two long peat cores and twelve 30-cm-long monoliths in 2008 along a 110-m transect from an expanding peatland margin toward the peatland center. Ecohydrologic changes were reconstructed from testate amoebae and plant macrofossils assemblages. Preliminary results from both long cores revealed a change in the vegetation assemblages from a mesotrophic fen dominated by sedges and brown mosses to a Sphagnum-dominated peat bog at 11 cm, suggesting a very recent modification of the local hydrologic regime. A simultaneous increase in moisture was reconstructed from testate amoebae records. These unusual shifts in peatland development and hydrology (e.g., wet conditions triggering the fen-bog transition) imply a recent increase of atmospheric water to these peatlands. Our ongoing lead-210 dating and additional proxy analysis will help us resolve the timing and nature of recent peatland changes. These data, together with glacier history and climate records, will allow us to further test our hypothesis that the increase in glacier meltwater is causing peatland expansion By acting as water sinks, peatlands located in glacierized watersheds may mediate the contribution of meltwater to present and future sea-level rise. Increases in peat accumulation rates due to favorable hydroclimatic conditions are also expected to promote carbon sequestration by these ecosystems. In contrast to the expected desiccation of peatlands under a warmer climate, enhanced growth due to glaciers-climate feedbacks in high-latitude regions may thus promote peatland expansion, even just temporally.

  13. Collaborative Research. Quantifying Climate Feedbacks of the Terrestrial Biosphere under Thawing Permafrost Conditions in the Arctic

    SciTech Connect

    Zhuang, Qianlai; Schlosser, Courtney; Melillo, Jerry; Walter, Katey

    2015-09-15

    Our overall goal is to quantify the potential for threshold changes in natural emission rates of trace gases, particularly methane and carbon dioxide, from pan-arctic terrestrial systems under the spectrum of anthropogenically-forced climate warming, and the conditions under which these emissions provide a strong feedback mechanism to global climate warming. This goal is motivated under the premise that polar amplification of global climate warming will induce widespread thaw and degradation of the permafrost, and would thus cause substantial changes to the landscape of wetlands and lakes, especially thermokarst (thaw) lakes, across the Arctic. Through a suite of numerical experiments that encapsulate the fundamental processes governing methane emissions and carbon exchanges – as well as their coupling to the global climate system - we intend to test the following hypothesis in the proposed research: There exists a climate warming threshold beyond which permafrost degradation becomes widespread and stimulates large increases in methane emissions (via thermokarst lakes and poorly-drained wetland areas upon thawing permafrost along with microbial metabolic responses to higher temperatures) and increases in carbon dioxide emissions from well-drained areas. Besides changes in biogeochemistry, this threshold will also influence global energy dynamics through effects on surface albedo, evapotranspiration and water vapor. These changes would outweigh any increased uptake of carbon (e.g. from peatlands and higher plant photosynthesis) and would result in a strong, positive feedback to global climate warming.

  14. Enhanced marine productivity off western North America during warm climate intervals of the past 52 k.y

    USGS Publications Warehouse

    Ortiz, J.D.; O'Connell, S. B.; DelViscio, J.; Dean, W.; Carriquiry, J.D.; Marchitto, T.; Zheng, Yen; VanGeen, A.

    2004-01-01

    Studies of the Santa Barbara Basin off the coast of California have linked changes in its bottom-water oxygen content to millennial-scale climate changes as recorded by the oxygen isotope composition of Greenland ice. Through the use of detailed records from a sediment core collected off the Magdalena Margin of Baja California, Mexico, we demonstrate that this teleconnection predominantly arose from changes in marine productivity, rather than changes in ventilation of the North Pacific, as was originally proposed. One possible interpretation is that the modern balance of El Nin??o-La Nin??a conditions that favors a shallow nutricline and high productivity today and during warm climate intervals of the past 52 k.y. was altered toward more frequent, deep nutricline, low productivity, El Nin??o-like conditions during cool climate intervals. ?? 2004 Geological Society of America.

  15. Evidence for 20th century climate warming and wetland drying in the North American Prairie Pothole Region

    PubMed Central

    Werner, Brett A; Johnson, W Carter; Guntenspergen, Glenn R

    2013-01-01

    The Prairie Pothole Region (PPR) of North America is a globally important resource that provides abundant and valuable ecosystem goods and services in the form of biodiversity, groundwater recharge, water purification, flood attenuation, and water and forage for agriculture. Numerous studies have found these wetlands, which number in the millions, to be highly sensitive to climate variability. Here, we compare wetland conditions between two 30-year periods (1946–1975; 1976–2005) using a hindcast simulation approach to determine if recent climate warming in the region has already resulted in changes in wetland condition. Simulations using the WETLANDSCAPE model show that 20th century climate change may have been sufficient to have a significant impact on wetland cover cycling. Modeled wetlands in the PPR's western Canadian prairies show the most dramatic effects: a recent trend toward shorter hydroperiods and less dynamic vegetation cycles, which already may have reduced the productivity of hundreds of wetland-dependent species. PMID:24223283

  16. Evidence for 20th century climate warming and wetland drying in the North American Prairie Pothole Region.

    PubMed

    Werner, Brett A; Johnson, W Carter; Guntenspergen, Glenn R

    2013-09-01

    The Prairie Pothole Region (PPR) of North America is a globally important resource that provides abundant and valuable ecosystem goods and services in the form of biodiversity, groundwater recharge, water purification, flood attenuation, and water and forage for agriculture. Numerous studies have found these wetlands, which number in the millions, to be highly sensitive to climate variability. Here, we compare wetland conditions between two 30-year periods (1946-1975; 1976-2005) using a hindcast simulation approach to determine if recent climate warming in the region has already resulted in changes in wetland condition. Simulations using the WETLANDSCAPE model show that 20th century climate change may have been sufficient to have a significant impact on wetland cover cycling. Modeled wetlands in the PPR's western Canadian prairies show the most dramatic effects: a recent trend toward shorter hydroperiods and less dynamic vegetation cycles, which already may have reduced the productivity of hundreds of wetland-dependent species. PMID:24223283

  17. Evidence for 20th century climate warming and wetland drying in the North American Prairie Pothole Region

    USGS Publications Warehouse

    Werner, B.A.; Johnson, W. Carter; Guntenspergen, Glenn R.

    2013-01-01

    The Prairie Pothole Region (PPR) of North America is a globally important resource that provides abundant and valuable ecosystem goods and services in the form of biodiversity, groundwater recharge, water purification, flood attenuation, and water and forage for agriculture. Numerous studies have found these wetlands, which number in the millions, to be highly sensitive to climate variability. Here, we compare wetland conditions between two 30-year periods (1946–1975; 1976–2005) using a hindcast simulation approach to determine if recent climate warming in the region has already resulted in changes in wetland condition. Simulations using the WETLANDSCAPE model show that 20th century climate change may have been sufficient to have a significant impact on wetland cover cycling. Modeled wetlands in the PPR's western Canadian prairies show the most dramatic effects: a recent trend toward shorter hydroperiods and less dynamic vegetation cycles, which already may have reduced the productivity of hundreds of wetland-dependent species.

  18. Constant diurnal temperature regime alters the impact of simulated climate warming on a tropical pseudoscorpion

    PubMed Central

    Zeh, Jeanne A.; Bonilla, Melvin M.; Su, Eleanor J.; Padua, Michael V.; Anderson, Rachel V.; Zeh, David W.

    2014-01-01

    Recent theory suggests that global warming may be catastrophic for tropical ectotherms. Although most studies addressing temperature effects in ectotherms utilize constant temperatures, Jensen's inequality and thermal stress considerations predict that this approach will underestimate warming effects on species experiencing daily temperature fluctuations in nature. Here, we tested this prediction in a neotropical pseudoscorpion. Nymphs were reared in control and high-temperature treatments under a constant daily temperature regime, and results compared to a companion fluctuating-temperature study. At constant temperature, pseudoscorpions outperformed their fluctuating-temperature counterparts. Individuals were larger, developed faster, and males produced more sperm, and females more embryos. The greatest impact of temperature regime involved short-term, adult exposure, with constant temperature mitigating high-temperature effects on reproductive traits. Our findings demonstrate the importance of realistic temperature regimes in climate warming studies, and suggest that exploitation of microhabitats that dampen temperature oscillations may be critical in avoiding extinction as tropical climates warm. PMID:24424082

  19. Constant diurnal temperature regime alters the impact of simulated climate warming on a tropical pseudoscorpion

    NASA Astrophysics Data System (ADS)

    Zeh, Jeanne A.; Bonilla, Melvin M.; Su, Eleanor J.; Padua, Michael V.; Anderson, Rachel V.; Zeh, David W.

    2014-01-01

    Recent theory suggests that global warming may be catastrophic for tropical ectotherms. Although most studies addressing temperature effects in ectotherms utilize constant temperatures, Jensen's inequality and thermal stress considerations predict that this approach will underestimate warming effects on species experiencing daily temperature fluctuations in nature. Here, we tested this prediction in a neotropical pseudoscorpion. Nymphs were reared in control and high-temperature treatments under a constant daily temperature regime, and results compared to a companion fluctuating-temperature study. At constant temperature, pseudoscorpions outperformed their fluctuating-temperature counterparts. Individuals were larger, developed faster, and males produced more sperm, and females more embryos. The greatest impact of temperature regime involved short-term, adult exposure, with constant temperature mitigating high-temperature effects on reproductive traits. Our findings demonstrate the importance of realistic temperature regimes in climate warming studies, and suggest that exploitation of microhabitats that dampen temperature oscillations may be critical in avoiding extinction as tropical climates warm.

  20. Metagenomics-Enabled Understanding of Soil Microbial Feedbacks to Climate Warming

    NASA Astrophysics Data System (ADS)

    Zhou, J.; Wu, L.; Zhili, H.; Kostas, K.; Luo, Y.; Schuur, E. A. G.; Cole, J. R.; Tiedje, J. M.

    2014-12-01

    Understanding the response of biological communities to climate warming is a central issue in ecology and global change biology, but it is poorly understood microbial communities. To advance system-level predictive understanding of the feedbacks of belowground microbial communities to multiple climate change factors and their impacts on soil carbon (C) and nitrogen (N) cycling processes, we have used integrated metagenomic technologies (e.g., target gene and shotgun metagenome sequencing, GeoChip, and isotope) to analyze soil microbial communities from experimental warming sites in Alaska (AK) and Oklahoma (OK), and long-term laboratory incubation. Rapid feedbacks of microbial communities to warming were observed in the AK site. Consistent with the changes in soil temperature, moisture and ecosystem respiration, microbial functional community structure was shifted after only 1.5-year warming, indicating rapid responses and high sensitivity of this permafrost ecosystem to climate warming. Also, warming stimulated not only functional genes involved in aerobic respiration of both labile and recalcitrant C, contributing to an observed 24% increase in 2010 growing season and 56% increase of decomposition of a standard substrate, but also functional genes for anaerobic processes (e.g., denitrification, sulfate reduction, methanogenesis). Further comparisons by shotgun sequencing showed significant differences of microbial community structure between AK and OK sites. The OK site was enriched in genes annotated for cellulose degradation, CO2 production, denitrification, sporulation, heat shock response, and cellular surface structures (e.g., trans-membrane transporters for glucosides), while the AK warmed plots were enriched in metabolic pathways related to labile C decomposition. Together, our results demonstrate the vulnerability of permafrost ecosystem C to climate warming and the importance of microbial feedbacks in mediating such vulnerability.

  1. Ocean Conditions, Salmon, and Climate Change

    E-print Network

    Ocean Conditions, Salmon, and Climate Change John Ferguson1 NOAA Fisheries Northwest Fisheries is dynamic · Multiple species increase and decrease in abundance over various time scales · For salmon, ocean productivity sets salmon recruitment levels - return rates can vary >10x with similar freshwater conditions

  2. Link between land-ocean warming contrast and surface relative humidities in simulations with coupled climate models

    E-print Network

    Byrne, Michael Patrick

    Simulations of warming climates with coupled climate models exhibit strong land-ocean contrasts in changes in surface temperature and relative humidity, but little land-ocean contrast in changes in equivalent potential ...

  3. Climatic Warming Increases Winter Wheat Yield but Reduces Grain Nitrogen Concentration in East China

    PubMed Central

    Deng, Aixing; Song, Zhenwei; Zhang, Baoming; Zhang, Weijian

    2014-01-01

    Climatic warming is often predicted to reduce wheat yield and grain quality in China. However, direct evidence is still lacking. We conducted a three-year experiment with a Free Air Temperature Increase (FATI) facility to examine the responses of winter wheat growth and plant N accumulation to a moderate temperature increase of 1.5°C predicted to prevail by 2050 in East China. Three warming treatments (AW: all-day warming; DW: daytime warming; NW: nighttime warming) were applied for an entire growth period. Consistent warming effects on wheat plant were recorded across the experimental years. An increase of ca. 1.5°C in daily, daytime and nighttime mean temperatures shortened the length of pre-anthesis period averagely by 12.7, 8.3 and 10.7 d (P<0.05), respectively, but had no significant impact on the length of the post-anthesis period. Warming did not significantly alter the aboveground biomass production, but the grain yield was 16.3, 18.1 and 19.6% (P<0.05) higher in the AW, DW and NW plots than the non-warmed plot, respectively. Warming also significantly increased plant N uptake and total biomass N accumulation. However, warming significantly reduced grain N concentrations while increased N concentrations in the leaves and stems. Together, our results demonstrate differential impacts of warming on the depositions of grain starch and protein, highlighting the needs to further understand the mechanisms that underlie warming impacts on plant C and N metabolism in wheat. PMID:24736557

  4. Teaching about Climate Change: Cool Schools Tackle Global Warming.

    ERIC Educational Resources Information Center

    Grant, Tim, Ed.; Littlejohn, Gail, Ed.

    Within the last couple of decades, the concentration of greenhouse gases in the atmosphere has increased significantly due to human activities. Today climate change is an important issue for humankind. This book provides a starting point for educators to teach about climate change, although there are obstacles caused by the industrialized…

  5. Warm Rain Processes Over the Tropical Oceans and Implications on Climate Change

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Wu, H. T.

    2004-01-01

    In this talk, we will first show results from TRMM regarding the characteristics of warm rains over the tropical oceans, and the dependence of rate of warm rain production on sea surface temperature. Results lead to the hypothesis that warm rain production efficiency, i.e., autoconversion, may be increased in a warm climate. We use the GEOS-II GCM to test this hypothesis. Our modeling results show that in a climate with increased rate of autoconversion, the total rain amount is increased, with warm rain contributing to a larger portion of the increase. The abundant rainout of warm precipitation at middle to low levels causes a reduction of high cloud cover due to the depletion of water available for ice-phase rain production. As a result, more isolated, but more intense penetrative convection develops. Results also show that increased autoconversion reduces the convective adjustment time scale tends, implying a faster recycling of atmospheric water. Most interestingly, the increased low level heating associated with warm rain leads to more energetic Madden and Julian oscillations in the tropics, with well-defined eastward propagation. While reducing the autoconversion leads to an abundant mix of westward and eastward tropical disturbance on daily to weekly time scales. The causes of the sensitivity of the dynamical regimes to the microphysics parameterization in the GCM will be discussed.

  6. Evaporation variability under climate warming in five reanalyses and its association with pan evaporation over China

    NASA Astrophysics Data System (ADS)

    Su, Tao; Feng, Taichen; Feng, Guolin

    2015-08-01

    With the motivation to identify actual evapotranspiration (AE) variability under climate warming over China, an assessment is made from five sets of reanalysis data sets [National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR), NCEP-Department of Energy (NCEP-DOE), Modern-Era Retrospective Analysis for Research and Applications (MERRA), Interim Reanalysis, and Japanese 55-year Reanalysis (JRA-55)]. Based on comparison with AE estimates calculated using the Budyko equation, all five reanalysis data sets reasonably reproduce the spatial patterns of AE over China, with a clearly southeast-northwest gradient. Overall, JRA-55 (NCEP-DOE) gives the lowest (highest) reanalysis evaporation (RE) values. From 1979 to 2013, dominant modes of RE among five reanalyses are extracted using multivariate empirical orthogonal function analysis. Accordingly, the interdecadal variation of RE is likely driven by the change of temperature, and the interannual variation is constrained by the water supply conditions. Under climate warming, RE increase in the Northwest China, Yangtze-Huaihe river basin, and South China, while they decrease in Qinghai-Tibet Plateau, and northern and Northeast China. Moreover, the relationship between RE and pan evaporation (PE) are comprehensively evaluated in space-time. Negative correlations are generally confirmed in nonhumid environments, while positive correlations exist in the humid regions. Our analysis supports the interpretation that the relationship between PE and AE was complementary with water control and proportional with energy control. In view of data availability, important differences in spatial variability and the amount of RE can be found in Northwest China, the Qinghai-Tibet Plateau, and the Yangtze River Basin. Generally speaking, NCEP-NCAR and MERRA have substantial problems on describing the long-term change of RE; however, there are some inaccuracies in the JRA-55 estimates when focusing on the year-to-year variation.

  7. Reconstruction of spatial patterns of climatic anomalies during the medieval warm period (AD 900-1300)

    SciTech Connect

    Diaz, H.F.; Hughes, M.K.

    1992-12-31

    The workshop will focus on climatic variations during the Medieval Warm Period or Little Climatic Optimum. The nominal time interval assigned to this period is AD 900--1300, but climate information available during the century or two preceding and following this episode is welcome. The aims of the workshop will be to: examine the available evidence for the existence of this episode; assess the spatial and temporal synchronicity of the climatic signals; discuss possible forcing mechanisms; and identify areas and paleoenvironmental records where additional research efforts are needed to improve our knowledge of this period. This document consists of abstracts of eighteen papers presented at the meeting.

  8. The integrated hydrologic and societal impacts of a warming climate in interior Alaska

    NASA Astrophysics Data System (ADS)

    Jones, Charles E., Jr.

    In this dissertation, interdisciplinary research methods were used to examine how changes in hydrology associated with climate affect Alaskans. Partnerships were established with residents of Fairbanks and Tanana to develop scientific investigations relevant to rural Alaskans. In chapter 2, local knowledge was incorporated into scientific models to identify a social-ecological threshold used to model potential driftwood harvest from the Yukon River. Anecdotal evidence and subsistence calendar records were combined with scientific data to model the harvest rates of driftwood. Modeling results estimate that between 1980 and 2010 hydrologic factors alone were responsible for a 29% decrease in the annual wood harvest, which approximately balanced a 23% reduction in wood demand due to a decline in number of households. The community's installation of wood-fired boilers in 2007 created a threshold increase (76%) in wood demand that is not met by driftwood harvest. Modeling of climatic scenarios illustrates that increased hydrologic variability decreases driftwood harvest and increases the financial or temporal costs for subsistence users. In chapter 3, increased groundwater flow related to permafrost degradation was hypothesized to be affect river ice thickness in sloughs of the Tanana River. A physically-based, numerical model was developed to examine the importance of permafrost degradation in explaining unfrozen river conditions in the winter. Results indicated that ice melt is amplified by increasing groundwater upwelling rates, groundwater temperatures, and snowfall. Modeling results also suggest that permafrost degradation could be a valid explanation of the phenomenon, but does not address the potential drivers (e.g. warming climate, forest fire, etc.) of the permafrost warming. In chapter 4, remote sensing techniques were hypothesized to be useful for mapping dangerous ice conditions on the Tanana River in interior Alaska. Unsupervised classification of high-resolution satellite imagery was used to identify and map open water and degraded ice conditions on the Tanana River. Ninety-five percent of the total river channel surface was classified as "safe" for river travel, while 4% of the channel was mapped as having degraded ice and 0.6% of the channel was classified as open water (overall accuracy of 73%). This research demonstrates that the classification of high-resolution satellite images can be useful for mapping hazardous ice for recreational, transportation, or industrial applications in northern climates. These results are applicable to communities throughout the North. For people that rely upon subsistence activities, increased variability in climate cycles can have substantial financial, cultural, recreational, or even mortal consequences. This research demonstrates how collaborations between scientists and local stakeholders can create tools that help to assess the impacts of increased environmental variability (such as flooding) or to detect or predict unsafe conditions (such as thin or unpredictable ice cover). Based upon this research, I conclude that regional-scale adaptations and technological advances (such as modeling and remote sensing tools) may help to alleviate the effects of environmental variability associated by climate.

  9. Beyond a warming fingerprint: individualistic biogeographic responses to heterogeneous climate change in California

    PubMed Central

    Rapacciuolo, Giovanni; Maher, Sean P; Schneider, Adam C; Hammond, Talisin T; Jabis, Meredith D; Walsh, Rachel E; Iknayan, Kelly J; Walden, Genevieve K; Oldfather, Meagan F; Ackerly, David D; Beissinger, Steven R

    2014-01-01

    Understanding recent biogeographic responses to climate change is fundamental for improving our predictions of likely future responses and guiding conservation planning at both local and global scales. Studies of observed biogeographic responses to 20th century climate change have principally examined effects related to ubiquitous increases in temperature – collectively termed a warming fingerprint. Although the importance of changes in other aspects of climate – particularly precipitation and water availability – is widely acknowledged from a theoretical standpoint and supported by paleontological evidence, we lack a practical understanding of how these changes interact with temperature to drive biogeographic responses. Further complicating matters, differences in life history and ecological attributes may lead species to respond differently to the same changes in climate. Here, we examine whether recent biogeographic patterns across California are consistent with a warming fingerprint. We describe how various components of climate have changed regionally in California during the 20th century and review empirical evidence of biogeographic responses to these changes, particularly elevational range shifts. Many responses to climate change do not appear to be consistent with a warming fingerprint, with downslope shifts in elevation being as common as upslope shifts across a number of taxa and many demographic and community responses being inconsistent with upslope shifts. We identify a number of potential direct and indirect mechanisms for these responses, including the influence of aspects of climate change other than temperature (e.g., the shifting seasonal balance of energy and water availability), differences in each taxon's sensitivity to climate change, trophic interactions, and land-use change. Finally, we highlight the need to move beyond a warming fingerprint in studies of biogeographic responses by considering a more multifaceted view of climate, emphasizing local-scale effects, and including a priori knowledge of relevant natural history for the taxa and regions under study. PMID:24934878

  10. Beyond a warming fingerprint: individualistic biogeographic responses to heterogeneous climate change in California.

    PubMed

    Rapacciuolo, Giovanni; Maher, Sean P; Schneider, Adam C; Hammond, Talisin T; Jabis, Meredith D; Walsh, Rachel E; Iknayan, Kelly J; Walden, Genevieve K; Oldfather, Meagan F; Ackerly, David D; Beissinger, Steven R

    2014-09-01

    Understanding recent biogeographic responses to climate change is fundamental for improving our predictions of likely future responses and guiding conservation planning at both local and global scales. Studies of observed biogeographic responses to 20th century climate change have principally examined effects related to ubiquitous increases in temperature - collectively termed a warming fingerprint. Although the importance of changes in other aspects of climate - particularly precipitation and water availability - is widely acknowledged from a theoretical standpoint and supported by paleontological evidence, we lack a practical understanding of how these changes interact with temperature to drive biogeographic responses. Further complicating matters, differences in life history and ecological attributes may lead species to respond differently to the same changes in climate. Here, we examine whether recent biogeographic patterns across California are consistent with a warming fingerprint. We describe how various components of climate have changed regionally in California during the 20th century and review empirical evidence of biogeographic responses to these changes, particularly elevational range shifts. Many responses to climate change do not appear to be consistent with a warming fingerprint, with downslope shifts in elevation being as common as upslope shifts across a number of taxa and many demographic and community responses being inconsistent with upslope shifts. We identify a number of potential direct and indirect mechanisms for these responses, including the influence of aspects of climate change other than temperature (e.g., the shifting seasonal balance of energy and water availability), differences in each taxon's sensitivity to climate change, trophic interactions, and land-use change. Finally, we highlight the need to move beyond a warming fingerprint in studies of biogeographic responses by considering a more multifaceted view of climate, emphasizing local-scale effects, and including a priori knowledge of relevant natural history for the taxa and regions under study. PMID:24934878

  11. Freezing of Martian streams under climatic conditions

    NASA Technical Reports Server (NTRS)

    Carr, M. H.

    1984-01-01

    The valley networks of Mars are widely believed to have formed at a time when climatic conditions on the planet were significantly different from those that currently prevail. This view arises from the following observations: (1) the valleys form integrated branching networks which suggests fluid drainage, and water is the most plausible fluid, (2) the present atmosphere contains only minute amounts of water, (3) the networks appear to be more akin to terrestrial valleys that are eroded by streams of modest discharges than features that form by catastrophic floods, and (4) small streams of water will rapidly freeze under present climatic conditions. Climatic conditions at the time of formation of the valleys are studied based on the assumption that they were cut by running water.

  12. Modelling high latitude climates and ice sheets during the mid-Pliocene warm period

    NASA Astrophysics Data System (ADS)

    Hill, D. J.; Haywood, A. M.; Hindmarsh, R. C.; Valdes, P. J.; Lunt, D. J.

    2007-12-01

    Reduction in the polar ice caps and associated climate feedbacks are implicated in the warming of pre- Quaternary palaeoclimates. General Circulation Model (GCM) simulations of the last such warm period, the mid- Pliocene (3.29-2.97 Ma), suggests global surface temperatures were between 1.4°C and 3.6°C warmer than today. However, the changes are amplified in the high latitudes, where the PRISM (Pliocene Research, Interpretation and Synoptic Mapping) palaeoenvironmental reconstruction specifies a 50% reduction in the Greenland Ice Sheet (GrIS) and a 33% reduction in the Antarctic Ice Sheet. These ice sheets configurations are largely based on poorly constrained sea level estimates and are one of the least well-known boundary conditions for the mid-Pliocene. Utilizing a suite of mid-Pliocene GCM experiments, evaluated against available palaeoenvironmental information, and a 3-D thermomechanically coupled ice sheet model, the state of the GrIS and East Antarctic Ice Sheet (EAIS) during this interval has been reconstructed. Ensemble models of Greenland, which compare favourably to evidence of ice-rafted debris and mid-Pliocene vegetation, suggest a reduction in the ice sheet to 30 - 40% of the modern ice volume. In East Antarctica increased surface temperatures during the mid-Pliocene lead to significant melt over the Wilkes and Aurora Subglacial Basins and a reduction in the extent of the ice sheet. These ice losses are partially offset by an increase in snowfall over the Antarctic plateau. Marine diatoms in the Transantarctic Mountains have been used as evidence of major East Antarctic deglaciations during the Pliocene. However, our EAIS predictions show that the modelled mid-Pliocene climate is insufficient to cause the hypothesized magnitude of ice sheet retreat. Finally, the mid-Pliocene has been suggested as a possible palaeoclimate analogue for the climate of the late 21st century. Here we compare predictions of mid-Pliocene ice sheets with observations of modern high latitude cryospheric change and discuss the implications for future ice sheet and climate stability of the high latitudes.

  13. Ecosystem resilience despite large-scale altered hydro climatic conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climate change is predicted to increase both drought frequency and duration, and when coupled with substantial warming, will establish a new hydroclimatological paradigm for many regions. Large-scale, warm droughts have recently impacted North America, Africa, Europe, Amazonia, and Australia result...

  14. WHAT TO DO ABOUT CLIMATE CHANGE? Slowing the rate of carbon burning won't stop global warming

    E-print Network

    Baez, John

    WHAT TO DO ABOUT CLIMATE CHANGE? #12;Slowing the rate of carbon burning won't stop global warming: most CO2 stays in the air over a century, though individual molecules come and go. Global warming. But we need to research it -- starting now. If global warming gets bad, public opinion may suddently flip

  15. Communicating Climate Uncertainties: Challenges and Opportunities Related to Spatial Scales, Extreme Events, and the Warming 'Hiatus'

    NASA Astrophysics Data System (ADS)

    Casola, J. H.; Huber, D.

    2013-12-01

    Many media, academic, government, and advocacy organizations have achieved sophistication in developing effective messages based on scientific information, and can quickly translate salient aspects of emerging climate research and evolving observations. However, there are several ways in which valid messages can be misconstrued by decision makers, leading them to inaccurate conclusions about the risks associated with climate impacts. Three cases will be discussed: 1) Issues of spatial scale in interpreting climate observations: Local climate observations may contradict summary statements about the effects of climate change on larger regional or global spatial scales. Effectively addressing these differences often requires communicators to understand local and regional climate drivers, and the distinction between a 'signal' associated with climate change and local climate 'noise.' Hydrological statistics in Missouri and California are shown to illustrate this case. 2) Issues of complexity related to extreme events: Climate change is typically invoked following a wide range of damaging meteorological events (e.g., heat waves, landfalling hurricanes, tornadoes), regardless of the strength of the relationship between anthropogenic climate change and the frequency or severity of that type of event. Examples are drawn from media coverage of several recent events, contrasting useful and potentially confusing word choices and frames. 3) Issues revolving around climate sensitivity: The so-called 'pause' or 'hiatus' in global warming has reverberated strongly through political and business discussions of climate change. Addressing the recent slowdown in warming yields an important opportunity to raise climate literacy in these communities. Attempts to use recent observations as a wedge between climate 'believers' and 'deniers' is likely to be counterproductive. Examples are drawn from Congressional testimony and media stories. All three cases illustrate ways that decision makers can arrive at invalid conclusions from a seemingly valid scientific messages. Honest discussion of uncertainties, and recognition of the spatial and time scales associated with decision making, can work to combat this potential confusion.

  16. Predicting organismal vulnerability to climate warming: roles of behaviour,

    E-print Network

    Huey, Raymond B.

    temperatures) that are often available for some groups. Several proxies for ectotherms are promising that ectotherms sharing vulnerability traits seem concentrated in lowland tropical forests. Their vulnerability, the prospects for tropical forest ectotherms appear grim. Keywords: climate change; ectotherms; endotherms

  17. Thermal state of permafrost in urban environment under changing climatic conditions

    NASA Astrophysics Data System (ADS)

    Grebenets, V. I.; Kerimov, A. G.; Shiklomanov, N. I.; Streletskiy, D. A.; Shkoda, V. S.; Anduschenko, F. D.

    2014-12-01

    Large industrial centers on permafrost are characterized by a set of geocryological conditions different from natural environment. Thermal state of foundations on permafrost in areas of economic development depends on climate trends and upon technogenic impacts, such as type of impact, area of facility, permafrost temperature and duration of the technogenic pressure. Technogenic degradation of permafrost is evident in most urban centers on permafrost leading to deterioration of geotechnical environment and particularly foundations of buildings and structures. This situation is exacerbated by climate warming in such cities as Vorkuta, Chita, Nerungry, Salekhard and others where temperature rises at a rate of 0.4 - 1.2 oC/decade over the last 40 years. To evaluate impact of climate warming and technogenic factors on permafrost temperature regime and foundation bearing capacity we compared five facilities in Norilsk, the largest city on permafrost. The facilities were selected to represent different parts of the town, different ages of built-up environment and were located in different permafrost and lithological conditions. We found a leading role of technogenic factors relative to climatic ones in dynamics of thermal state of permafrost in urban environment. Climate warming in Norilsk (0.15 oC/decade) was a small contributor, but gave an additional input to deterioration of geotechnical environment on permafrost. At the same time, implementation of engineering solutions of permafrost temperature cooling (such as crawl spaces) result in lowering of permafrost temperature. Field surveys in Yamburg showed that under some facilities permafrost temperature decreased by 1-1.5 C oC over the last 15 years despite pronounced in the region climate warming of 0.5 oC/decade. This shows that despite deterioration of permafrost conditions in the most Arctic regions due to technogenic pressure and climate warming, implementation of adequate engineering solutions allows stabilization of permafrost thermal regime.

  18. Global and regional surface cooling in a warming climate: a multi-model analysis

    NASA Astrophysics Data System (ADS)

    Medhaug, Iselin; Drange, Helge

    2015-09-01

    Instrumental temperature records show that the global climate may experience decadal-scale periods without warming despite a long-term warming trend. We analysed 17 global climate models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5), identifying the likelihood and duration of periods without warming in the four Representative Concentration Pathway (RCP) scenarios RCP2.6, RCP4.5, RCP6.0 and RCP8.5, together with the preindustrial control and historical simulations. We find that non-warming periods may last 10, 15 and 30 years for RCP8.5, RCP6.0 and RCP4.5, respectively. In the models, anomalous ocean heat uptake and storage are the main factors explaining the decadal-scale surface temperature hiatus periods. The low-latitude East Pacific Ocean is a key region for these variations, acting in tandem with basin-scale anomalies in the sea level pressure. During anomalously cold decades, roughly 35-50 % of the heat anomalies in the upper 700 m of the ocean are located in the Pacific Ocean, and 25 % in the Atlantic Ocean. Decadal-scale ocean heat anomalies, integrated over the upper 700 m, have a magnitude of about 7.5 × 1021 J. This is comparable to the ocean heat uptake needed to maintain a 10 year period without increasing surface temperature under global warming. On sub-decadal time scales the Atlantic, Pacific and Southern Oceans all have the ability to store large amounts of heat, contributing to variations in global surface temperature. The likelihood of decadal-scale non-warming periods decrease with global warming, firstly at the low latitude region stretching eastward from the tropical Atlantic towards the western Pacific. The North Atlantic and Southern Oceans have largest likelihood of non-warming decades in a warming world.

  19. A brief history of climate e the northern seas from the Last Glacial Maximum to global warming

    E-print Network

    Drange, Helge

    A brief history of climate e the northern seas from the Last Glacial Maximum to global warming Tor, and Bjerknes Centre for Climate Research, Bergen, Norway b Uni Research Climate, and Bjerknes Centre for Climate Research, Bergen, Norway c Department of Biology, University of Bergen, and Bjerknes Centre

  20. Large impacts of climatic warming on growth of boreal forests since 1960.

    PubMed

    Kauppi, Pekka E; Posch, Maximilian; Pirinen, Pentti

    2014-01-01

    Boreal forests are sensitive to climatic warming, because low temperatures hold back ecosystem processes, such as the mobilization of nitrogen in soils. A greening of the boreal landscape has been observed using remote sensing, and the seasonal amplitude of CO2 in the northern hemisphere has increased, indicating warming effects on ecosystem productivity. However, field observations on responses of ecosystem productivity have been lacking on a large sub-biome scale. Here we report a significant increase in the annual growth of boreal forests in Finland in response to climatic warming, especially since 1990. This finding is obtained by linking meteorological records and forest inventory data on an area between 60° and 70° northern latitude. An additional increase in growth has occurred in response to changes in other drivers, such as forest management, nitrogen deposition and/or CO2 concentration. A similar warming impact can be expected in the entire boreal zone, where warming takes place. Given the large size of the boreal biome - more than ten million km2- important climate feedbacks are at stake, such as the future carbon balance, transpiration and albedo. PMID:25383552

  1. Large Impacts of Climatic Warming on Growth of Boreal Forests since 1960

    PubMed Central

    Kauppi, Pekka E.; Posch, Maximilian; Pirinen, Pentti

    2014-01-01

    Boreal forests are sensitive to climatic warming, because low temperatures hold back ecosystem processes, such as the mobilization of nitrogen in soils. A greening of the boreal landscape has been observed using remote sensing, and the seasonal amplitude of CO2 in the northern hemisphere has increased, indicating warming effects on ecosystem productivity. However, field observations on responses of ecosystem productivity have been lacking on a large sub-biome scale. Here we report a significant increase in the annual growth of boreal forests in Finland in response to climatic warming, especially since 1990. This finding is obtained by linking meteorological records and forest inventory data on an area between 60° and 70° northern latitude. An additional increase in growth has occurred in response to changes in other drivers, such as forest management, nitrogen deposition and/or CO2 concentration. A similar warming impact can be expected in the entire boreal zone, where warming takes place. Given the large size of the boreal biome – more than ten million km2– important climate feedbacks are at stake, such as the future carbon balance, transpiration and albedo. PMID:25383552

  2. Boreal Forests in Permafrost Landscapes: Changing Structure and Function in Response to Climate Warming

    NASA Astrophysics Data System (ADS)

    Baltzer, J. L.; Quinton, W. L.; Sonnentag, O.

    2014-12-01

    Boreal forests occupy latitudes that are experiencing the greatest rates of warming on earth, a pattern that is expected to continue over the coming decades. Much of the Boreal is underlain by permafrost, which can be expected to have important consequences for forest structure, composition and functioning as the climate warms. The southern margin of permafrost is especially susceptible to warming, since in this region, the permafrost is discontinuous, relatively thin, warm and ice-rich. In the discontinuous permafrost zone, permafrost often forms the physical foundation on which trees develop, forming tree-covered peat plateaus where trees contribute to permafrost maintenance and aggradation processes through reductions in radiation load and changes in snow accumulation. Forests are restricted to peat plateaus while wetland communities occupy intervening permafrost-free areas. The extent and distribution of each land cover type is an important determinant of how boreal forest-wetland landscapes in the discontinuous permafrost zone function as part of the climate system. Climate warming is rapidly thawing permafrost leading to ground surface subsidence and transformation of the forests into wetlands, increasing both the areal extent and connectivity of the latter. In this presentation, we will use an integrative framework at the ForestGEO Scotty Creek Forest Dynamics Plot site near Fort Simpson, Northwest Territories, Canada to demonstrate the changes in ecological, hydrological and biosphere-atmosphere interactions within this boreal forest-wetland landscape characterized by rapidly degrading permafrost.

  3. Responses of community-level plant-insect interactions to climate warming in a meadow steppe

    PubMed Central

    Zhu, Hui; Zou, Xuehui; Wang, Deli; Wan, Shiqiang; Wang, Ling; Guo, Jixun

    2015-01-01

    Climate warming may disrupt trophic interactions, consequently influencing ecosystem functioning. Most studies have concentrated on the temperature-effects on plant-insect interactions at individual and population levels, with a particular emphasis on changes in phenology and distribution. Nevertheless, the available evidence from the community level is limited. A 3-year field manipulative experiment was performed to test potential responses of plant and insect communities, and plant-insect interactions, to elevated temperature in a meadow steppe. Warming increased the biomass of plant community and forbs, and decreased grass biomass, indicating a shift from grass-dominant to grass-forb mixed plant community. Reduced abundance of the insect community under warming, particularly the herbivorous insects, was attributed to lower abundance of Euchorthippus unicolor and a Cicadellidae species resulting from lower food availability and higher defensive herbivory. Lower herbivore abundance caused lower predator species richness because of reduced prey resources and contributed to an overall decrease in insect species richness. Interestingly, warming enhanced the positive relationship between insect and plant species richness, implying that the strength of the plant-insect interactions was altered by warming. Our results suggest that alterations to plant-insect interactions at a community level under climate warming in grasslands may be more important and complex than previously thought. PMID:26686758

  4. Responses of community-level plant-insect interactions to climate warming in a meadow steppe.

    PubMed

    Zhu, Hui; Zou, Xuehui; Wang, Deli; Wan, Shiqiang; Wang, Ling; Guo, Jixun

    2015-01-01

    Climate warming may disrupt trophic interactions, consequently influencing ecosystem functioning. Most studies have concentrated on the temperature-effects on plant-insect interactions at individual and population levels, with a particular emphasis on changes in phenology and distribution. Nevertheless, the available evidence from the community level is limited. A 3-year field manipulative experiment was performed to test potential responses of plant and insect communities, and plant-insect interactions, to elevated temperature in a meadow steppe. Warming increased the biomass of plant community and forbs, and decreased grass biomass, indicating a shift from grass-dominant to grass-forb mixed plant community. Reduced abundance of the insect community under warming, particularly the herbivorous insects, was attributed to lower abundance of Euchorthippus unicolor and a Cicadellidae species resulting from lower food availability and higher defensive herbivory. Lower herbivore abundance caused lower predator species richness because of reduced prey resources and contributed to an overall decrease in insect species richness. Interestingly, warming enhanced the positive relationship between insect and plant species richness, implying that the strength of the plant-insect interactions was altered by warming. Our results suggest that alterations to plant-insect interactions at a community level under climate warming in grasslands may be more important and complex than previously thought. PMID:26686758

  5. The Response of A Coupled Climate Model To Transient Fluxes From A Global Warming Experiment.

    NASA Astrophysics Data System (ADS)

    Eby, M.; Gregory, J. M.; Saenko, O. A.; Schmittner, A.; Weaver, A. J.

    The response of the UVic Earth System Climate Model to forcing from a global warm- ing run is investigated. Four additional transient experiments were performed to look at the relative contribution of fresh water and heat fluxes. The experiments consisted of prescribing freshwater fluxes, either above or below the sea ice, from a transient global warming run to a present day simulation and the present day fluxes to a tran- sient global warming run. These experiments show that the reduction in North Atlantic overturning with global warming is dominated by changes in heat flux in this model. Fresh water fluxes account for about one quarter of the reduction. It is also found that the increased flux of fresh water from the atmosphere to the North Atlantic in a global warming run is enough to make the overturning collapse in a present day simulation. In a similar present day experiment, it is found that the redistribution of fresh wa- ter flux from exported sea ice in the global warming climate actually increases the overturning, even with the increased atmospheric fresh water flux. These experiments demonstrate that the distribution of both heat and fresh water near the deep water for- mation regions is critical in how the thermohaline circulation responds. They show that the treatment of both convection and sea ice are important and demonstrate po- tential difficulties in trying to look at the separate responses of a nonlinear system to fluxes which are in places highly corelated.

  6. Impacts of peatland forestation on regional climate conditions in Finland

    NASA Astrophysics Data System (ADS)

    Gao, Yao; Markkanen, Tiina; Backman, Leif; Henttonen, Helena M.; Pietikäinen, Joni-Pekka; Laaksonen, Ari

    2014-05-01

    Climate response to anthropogenic land cover change happens more locally and occurs on a shorter time scale than the global warming due to increased GHGs. Over the second half of last Century, peatlands were vastly drained in Finland to stimulate forest growth for timber production. In this study, we investigate the biophysical effects of peatland forestation on near-surface climate conditions in Finland. For this, the regional climate model REMO, developed in Max Plank Institute (currently in Climate Service Center, Germany), provides an effective way. Two sets of 15-year climate simulations were done by REMO, using the historic (1920s; The 1st Finnish National Forest Inventory) and present-day (2000s; the 10th Finnish National Forest Inventory) land cover maps, respectively. The simulated surface air temperature and precipitation were then analyzed. In the most intensive peatland forestation area in Finland, the differences in monthly averaged daily mean surface air temperature show a warming effect around 0.2 to 0.3 K in February and March and reach to 0.5 K in April, whereas a slight cooling effect, less than 0.2 K, is found from May till October. Consequently, the selected snow clearance dates in model gridboxes over that area are advanced 0.5 to 4 days in the mean of 15 years. The monthly averaged precipitation only shows small differences, less than 10 mm/month, in a varied pattern in Finland from April to September. Furthermore, a more detailed analysis was conducted on the peatland forestation area with a 23% decrease in peatland and a 15% increase in forest types. 11 day running means of simulated temperature and energy balance terms, as well as snow depth were averaged over 15 years. Results show a positive feedback induced by peatland forestation between the surface air temperature and snow depth in snow melting period. This is because the warmer temperature caused by lower surface albedo due to more forest in snow cover period leads to a quicker and earlier snow melting. Meanwhile, surface albedo is reduced and consequently surface air temperature is increased. Additionally, the maximum difference from individual gridboxes in this area over 15 years of 11 day running means of daily mean surface air temperature reaches 2 K, which is four times as much as the maximum difference of 15-year regional average of that. This illustrates that the spring warming effect from peatland forestation in Finland is highly heterogeneous spatially and temporally.

  7. Global warming impacts of ozone-safe refrigerants and refrigeration, heating, and air-conditioning technologies

    SciTech Connect

    Fischer, S.; Sand, J.; Baxter, V.

    1997-12-01

    International agreements mandate the phase-out of many chlorine containing compounds that are used as the working fluid in refrigeration, air-conditioning, and heating equipment. Many of the chemical compounds that have been proposed, and are being used in place of the class of refrigerants eliminated by the Montreal Protocol are now being questioned because of their possible contributions to global warming. Natural refrigerants are put forth as inherently superior to manufactured refrigerants because they have very low or zero global warming potentials (GWPs). Questions are being raised about whether or not these manufactured refrigerants, primarily hydrofluorocarbons (HFCs), should be regulated and perhaps phased out in much the same manner as CFCs and HCFCs. Several of the major applications of refrigerants are examined in this paper and the results of an analysis of their contributions to greenhouse warming are presented. Supermarket refrigeration is shown to be an application where alternative technologies have the potential to reduce emissions of greenhouse gases (GHG) significantly with no clear advantage to either natural or HFC refrigerants. Mixed results are presented for automobile air conditioners with opportunities to reduce GHG emissions dependent on climate and comfort criteria. GHG emissions for hermetic and factory built systems (i.e. household refrigerators/freezers, unitary equipment, chillers) are shown to be dominated by energy use with much greater potential for reduction through efficiency improvements than by selection of refrigerant. The results for refrigerators also illustrate that hydrocarbon and carbon dioxide blown foam insulation have lower overall effects on GHG emissions than HFC blown foams at the cost of increased energy use.

  8. Increases in flood magnitudes in California under warming climates

    NASA Astrophysics Data System (ADS)

    Das, Tapash; Maurer, Edwin P.; Pierce, David W.; Dettinger, Michael D.; Cayan, Daniel R.

    2013-09-01

    Downscaled and hydrologically modeled projections from an ensemble of 16 Global Climate Models suggest that flooding may become more intense on the western slopes of the Sierra Nevada mountains, the primary source for California's managed water system. By the end of the 21st century, all 16 climate projections for the high greenhouse-gas emission SRES A2 scenario yield larger floods with return periods ranging 2-50 years for both the Northern Sierra Nevada and Southern Sierra Nevada, regardless of the direction of change in mean precipitation. By end of century, discharges from the Northern Sierra Nevada with 50-year return periods increase by 30-90% depending on climate model, compared to historical values. Corresponding flood flows from the Southern Sierra increase by 50-100%. The increases in simulated 50 year flood flows are larger (at 95% confidence level) than would be expected due to natural variability by as early as 2035 for the SRES A2 scenario.

  9. Dusting the climate for fingerprints. Has greenhouse warming arrived? Will we ever know?

    SciTech Connect

    Monastersy, R.

    1995-06-10

    The topic of global warming is front page news again. Although the annual average global temperature has risen by about 0.5 C since the late 19th century, investigators have had difficulty determining whether natural forces or human actions are to blame. This article summarizes the arguments pro and con and the search for a diffinative `human fingerprint` on global warming. For example, Max-Lanck researchers find it highly imporbable (1 in 20 chance) that natural forcers have caused the temperature rise. However other scientists acknowledge that uncertainties continue to plague studies aimed at detecting the human influence in climatic change. Computer climate models are the major approach, but distiguishing between recent abnormal warming due to greenhouse gases or to other causes is elusive.

  10. Ecological contingency in the effects of climatic warming on forest herb communities

    E-print Network

    Harrison, Susan

    Ecological contingency in the effects of climatic warming on forest herb communities Susan change in understory herb communities over a 60-y period (1949/1951­2007/ 2009) in a complex montane,500­2,100 m above sea level). In lower montane forests, regardless of land-use history, we found multiple herb

  11. Climate Warming and Adaptability of High-Elevation Hydropower Generation in California

    E-print Network

    Keller, Arturo A.

    and allows more hydropower generation in the summer when energy price is greater. Currently, CaliforniaClimate Warming and Adaptability of High-Elevation Hydropower Generation in California Kaveh Madani's high-elevation hydropower system is composed of more than 150 power plants. Most of the associated

  12. Variation in climate warming along the migration route uncouples arrival and breeding dates

    E-print Network

    Laaksonen, Toni

    Variation in climate warming along the migration route uncouples arrival and breeding dates M A R K and at the breeding grounds. Here we show that migration and breeding times of a trans-Saharan migrant, the pied and at the breeding grounds. Because of differences in long-term temperature trends of short within-spring periods

  13. Can behavior douse the fire of climate warming? Raymond B. Huey1

    E-print Network

    Huey, Raymond B.

    ­9) that does just that. Kearny et al. (6) quantify whether a diurnal ectotherm's use of behavioral adjustments-zone ectotherms live in environments that are considerably cooler than their optimum, and so be- coming warmer and continental- desert ectotherms is staying cool. Climate warming will place them at risk, especially if shade

  14. An Alternative View of the Climate Warming Mitigation Potential of U.S. Temperate Forests

    EPA Science Inventory

    Many U.S. federal and non-governmental agencies promote forestation as a means to mitigate climate warming because of the carbon sequestration potential of forests. This biogeochemical-oriented carbon sequestration policy is somewhat inconsistent with a decade or more of researc...

  15. Impact of climate change on stratospheric sudden warmings as simulated by the

    E-print Network

    Wirosoetisno, Djoko

    Hemi- sphere winter stratosphere: polar temperatures undergo a rapid increase that reverses stratospheric clouds (PSCs), which activate chlorine and lead to chemical ozone loss in the presence of sunlightImpact of climate change on stratospheric sudden warmings as simulated by the Canadian middle

  16. The effects of climate uncertainty on the stability of the Antarctic ice sheet during the mid-Pliocene warm period

    NASA Astrophysics Data System (ADS)

    Bernales, Jorge; Häfliger, Tonio; Rogozhina, Irina; Thomas, Maik

    2015-04-01

    The mid-Pliocene (3.15 to 2.85 million years before present) is the most recent period in Earth's history when temperatures and CO2 concentrations were sustainedly higher than pre-industrial values [1], representing an ideal interval for studying the climate system under conditions similar to those projected for the end of this century. In these projections, the response of the Antarctic ice sheet (AIS) remains uncertain, including areas generally considered stable under a warming climate. Therefore, a better understanding of AIS's behaviour during periods like the mid-Pliocene will provide valuable information on the potential vulnerability of the composite parts of the AIS in the future. For this purpose, we have designed numerical experiments of the AIS dynamics during the mid-Pliocene warm period using the continental-scale ice sheet-shelf model SICOPOLIS [2]. To account for the uncertainties in the configuration of the AIS and climate conditions prior to this period, we employ a wide range of initial ice sheet configurations and climatologies, including modern observations, the results from the Pliocene Model Intercomparison Project (PlioMIP) climate experiments [3], and perturbations to single climatic fields, allowing us to assess the vulnerability of different AIS sectors to specific forcing mechanisms. Our simulations show that the West Antarctic ice sheet remains largely ice-free under the chosen range of climate conditions, except for small portions grounded above sea level. On the contrary, the East Antarctic ice sheet (EAIS) shows no signs of potential collapse, with an ice loss over a few peripheral sectors largely compensated by an increase in ice volume over the interior due to increased precipitation rates and surface temperatures remaining well below the freezing point. Furthermore, our results contrast with existing hypotheses that cast doubt on the stability of the EAIS during the mid-Pliocene warm period. References [1] Cook, C. P., et al. Dynamic behaviour of the East Antarctic ice sheet during Pliocene warmth. Nature Geoscience 6.9 (2013): 765-769. [2] Sato, T., and Greve, R. Sensitivity experiments for the Antarctic ice sheet with varied sub-ice-shelf melting rates. Annals of Glaciology 53.60 (2012): 221-228. [3] Haywood, A. M., et al. Large-scale features of Pliocene climate: results from the Pliocene Model Intercomparison Project. Clim. Past 9 (2013): 191-209.

  17. Simulated climate warming alters phenological synchrony between an outbreak insect herbivore and host trees.

    PubMed

    Schwartzberg, Ezra G; Jamieson, Mary A; Raffa, Kenneth F; Reich, Peter B; Montgomery, Rebecca A; Lindroth, Richard L

    2014-07-01

    As the world's climate warms, the phenologies of interacting organisms in seasonally cold environments may advance at differing rates, leading to alterations in phenological synchrony that can have important ecological consequences. For temperate and boreal species, the timing of early spring development plays a key role in plant-herbivore interactions and can influence insect performance, outbreak dynamics, and plant damage. We used a field-based, meso-scale free-air forest warming experiment (B4WarmED) to examine the effects of elevated temperature on the phenology and performance of forest tent caterpillar (Malacosoma disstria) in relation to the phenology of two host trees, aspen (Populus tremuloides) and birch (Betula papyrifera). Results of our 2-year study demonstrated that spring phenology advanced for both insects and trees, with experimentally manipulated increases in temperature of 1.7 and 3.4 °C. However, tree phenology advanced more than insect phenology, resulting in altered phenological synchrony. Specifically, we observed a decrease in the time interval between herbivore egg hatch and budbreak of aspen in both years and birch in one year. Moreover, warming decreased larval development time from egg hatch to pupation, but did not affect pupal mass. Larvae developed more quickly on aspen than birch, but pupal mass was not affected by host species. Our study reveals that warming-induced phenological shifts can alter the timing of ecological interactions across trophic levels. These findings illustrate one mechanism by which climate warming could mediate insect herbivore outbreaks, and also highlights the importance of climate change effects on trophic interactions. PMID:24889969

  18. Comparison of "warm and wet" and "cold and icy" scenarios for early Mars in a 3-D climate model

    NASA Astrophysics Data System (ADS)

    Wordsworth, Robin D.; Kerber, Laura; Pierrehumbert, Raymond T.; Forget, Francois; Head, James W.

    2015-06-01

    We use a 3-D general circulation model to compare the primitive Martian hydrological cycle in "warm and wet" and "cold and icy" scenarios. In the warm and wet scenario, an anomalously high solar flux or intense greenhouse warming artificially added to the climate model are required to maintain warm conditions and an ice-free northern ocean. Precipitation shows strong surface variations, with high rates around Hellas basin and west of Tharsis but low rates around Margaritifer Sinus (where the observed valley network drainage density is nonetheless high). In the cold and icy scenario, snow migration is a function of both obliquity and surface pressure, and limited episodic melting is possible through combinations of seasonal, volcanic, and impact forcing. At surface pressures above those required to avoid atmospheric collapse (˜0.5 bar) and moderate to high obliquity, snow is transported to the equatorial highland regions where the concentration of valley networks is highest. Snow accumulation in the Aeolis quadrangle is high, indicating an ice-free northern ocean is not required to supply water to Gale crater. At lower surface pressures and obliquities, both H2O and CO2 are trapped as ice at the poles and the equatorial regions become extremely dry. The valley network distribution is positively correlated with snow accumulation produced by the cold and icy simulation at 41.8° obliquity but uncorrelated with precipitation produced by the warm and wet simulation. Because our simulations make specific predictions for precipitation patterns under different climate scenarios, they motivate future targeted geological studies.

  19. Quantifying the influence of observed global warming on the probability of unprecedented extreme climate events

    NASA Astrophysics Data System (ADS)

    Diffenbaugh, N. S.; Rajaratnam, B.; Charland, A.; Haugen, M.; Horton, D. E.; Singh, D.; Swain, D. L.; Tsiang, M.

    2014-12-01

    Now that observed global warming has been clearly attributed to human activities, there has been increasing interest in the extent to which that warming has influenced the occurrence and severity of individual extreme climate events. However, although trends in the extremes of the seasonal- and daily-scale distributions of climate records have been analyzed for many years, quantifying the contribution of observed global warming to individual events that are unprecedented in the observed record presents a particular scientific challenge. We will describe a modified method for leveraging observations and large climate model ensembles to quantify the influence of observed global warming on the probability of unprecedented extreme events. In this approach, we first diagnose the causes of the individual event in order to understand which climate processes to target in the probability quantification. We then use advanced statistical techniques to quantify the uncertainty in the return period of the event in the observed record. We then use large ensembles of climate model simulations to quantify the distribution of return period ratios between the current level of climate forcing and the pre-industrial climate forcing. We will compare the structure of this approach to other approaches that exist in the literature. We will then examine a set of individual extreme events that have been analyzed in the literature, and compare the results of our approach with those that have been previously published. We will conclude with a discussion of the observed agreement and disagreement between the different approaches, including implications for interpretation of the role of human forcing in shaping unprecedented extreme events.

  20. Climate warming feedback from mountain birch forest expansion: reduced albedo dominates carbon uptake.

    PubMed

    de Wit, Heleen A; Bryn, Anders; Hofgaard, Annika; Karstensen, Jonas; Kvalevåg, Maria M; Peters, Glen P

    2014-07-01

    Expanding high-elevation and high-latitude forest has contrasting climate feedbacks through carbon sequestration (cooling) and reduced surface reflectance (warming), which are yet poorly quantified. Here, we present an empirically based projection of mountain birch forest expansion in south-central Norway under climate change and absence of land use. Climate effects of carbon sequestration and albedo change are compared using four emission metrics. Forest expansion was modeled for a projected 2.6 °C increase in summer temperature in 2100, with associated reduced snow cover. We find that the current (year 2000) forest line of the region is circa 100 m lower than its climatic potential due to land-use history. In the future scenarios, forest cover increased from 12% to 27% between 2000 and 2100, resulting in a 59% increase in biomass carbon storage and an albedo change from 0.46 to 0.30. Forest expansion in 2100 was behind its climatic potential, forest migration rates being the primary limiting factor. In 2100, the warming caused by lower albedo from expanding forest was 10 to 17 times stronger than the cooling effect from carbon sequestration for all emission metrics considered. Reduced snow cover further exacerbated the net warming feedback. The warming effect is considerably stronger than previously reported for boreal forest cover, because of the typically low biomass density in mountain forests and the large changes in albedo of snow-covered tundra areas. The positive climate feedback of high-latitude and high-elevation expanding forests with seasonal snow cover exceeds those of afforestation at lower elevation, and calls for further attention of both modelers and empiricists. The inclusion and upscaling of these climate feedbacks from mountain forests into global models is warranted to assess the potential global impacts. PMID:24343906

  1. Floods, Droughts and Global Warming: Rolling the Climate Dice

    NASA Astrophysics Data System (ADS)

    Lau, W. K.; Wu, H.; Kim, K.

    2013-12-01

    In this study, we find from analyses of projections of 14 CMIP5 models a robust, canonical global response in rainfall characteristics to CO2 greenhouse warming. Under a scenario of 1% increase per year of CO2 emission, the model ensemble projects globally more heavy precipitation (+7×2.4%K-1), less moderate precipitation (-2.5×0.6%K-1), more light precipitation (+1.8×1.3%K-1), and increased length of dry (no-rain) periods (+4.7×2.1%K-1). Regionally, a majority of the models project a consistent response with more heavy precipitation over climatologically wet regions of the deep tropics especially the equatorial Pacific Ocean and the Asian monsoon regions, and more dry periods over the land areas of the subtropics and the tropical marginal convective zones. Changes in the global circulation associated with the precipitation changes include a narrowing and deepening of convective zone, a rise of the center of gravity and acceleration of the upper branch of the Hadley circulation, an expansion of the subtropics and a poleward shift of the jetstream. Our results suggest that increased risks of severe floods and droughts worldwide induced by increased CO2 emission is the manifestation of a canonical response of the global rainfall system in association with a re-adjustment of the global circulation system, in a competition for increased availability of atmospheric moisture from global warming.

  2. Humidity critical for grass growth in warming climates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant growth responses to climate change might be confounded by multi-factor changes such as temperature and vapor pressure deficit (VPD). The growth and water loss of tall fescue (Festuca arundinaccea Schreb.), a cool season grass, was measured over 6 weeks with independent control of temperature a...

  3. [Effects of climate warming and drying on millet yield in Gansu Province and related countermeasures].

    PubMed

    Cao, Ling; Wang, Qiang; Deng, Zhen-yong; Guo, Xiao-qin; Ma, Xing-xiang; Ning, Hui-fang

    2010-11-01

    Based on the data of air temperature, precipitation, and millet yield from Ganzhou, Anding, and Xifeng, the representative stations in Hexi moderate arid oasis irrigation area, moderate sub-arid dry area in middle Gansu, and moderate sub-humid dry area in eastern Gansu, respectively, this paper calculated the regional active accumulated temperature of > or = 0 degrees C, > or =5 degrees C, > or =10 degrees C, > or =15 degrees C, and > or =20 degrees C in millet growth period, and the average temperature and precipitation in millet key growth stages. The millet climatic yield was isolated by orthogonal polynomial, and the change characteristics of climate and millet climatic yield as well as the effects of climate change on millet yield were analyzed by statistical methods of linear tendency, cumulative anomaly, and Mann-Kendall. The results showed that warming and drying were the main regional features in the modern climatic change of Gansu. The regional temperature had a significant upward trend since the early 1990s, while the precipitation was significantly reduced from the late 1980s. There were significant correlations between millet yield and climatic factors. The millet yield in dry areas increased with the increasing temperature and precipitation in millet key growth stages, and that in Hexi Corridor area increased with increasing temperature. Warming and drying affected millet yield prominently. The weather fluctuation index of regional millet yield in Xifeng, Anding, and Ganzhou accounted for 73%, 72%, and 54% of real output coefficient variation, respectively, and the percentages increased significantly after warming. Warming was conducive to the increase of millet production, and the annual increment of millet climatic yield in Xifeng, Anding, and Ganzhou after warming was 30.6, 43.1, and 121.1 kg x hm(-2), respectively. Aiming at the warming and drying trend in Gansu Province in the future, the millet planting area in the Province should be further expanded, and the millet planting structure should be adjusted. At the same time, according to the different regional and yearly climatic types, different varieties should be selected, and various planting measures should be taken. PMID:21361020

  4. Using multiple equilibria in precipitation to understand self-aggregation of deep tropical convection in a warming climate

    NASA Astrophysics Data System (ADS)

    Sessions, Sharon; Sentic, Stipo; Raymond, David

    2013-03-01

    Understanding mechanisms of convective organization is currently an important problem in tropical meteorology. Recent numerical simulations show that the tendency for deep tropical convection to self-aggregate increases as sea surface temperatures (SSTs) increase. This has significant implications for hurricane genesis in a warming climate. Investigating the conditions over which convection self-aggregates requires large domains and is therefore computationally expensive. An alternative approach utilizes the analogy between multiple equilibria in limited domain simulations, and the dry and precipitating regions in a large domain with self-aggregated convection. Multiple equilibria refers to a steady state which either exhibits a completely dry troposphere or persistent precipitating deep convection under identical forcing conditions. The large scale circulation is parameterized based on the assumption that horizontal gradients in temperature are small in the tropics. Understanding the mechanisms which permit multiple equilibria on small domains is a computationally economic approach to understanding self-aggregation. We show how multiple equilibria depend on SSTs, and thus provide insight to self-aggregation in a warming climate. Understanding mechanisms of convective organization is currently an important problem in tropical meteorology. Recent numerical simulations show that the tendency for deep tropical convection to self-aggregate increases as sea surface temperatures (SSTs) increase. This has significant implications for hurricane genesis in a warming climate. Investigating the conditions over which convection self-aggregates requires large domains and is therefore computationally expensive. An alternative approach utilizes the analogy between multiple equilibria in limited domain simulations, and the dry and precipitating regions in a large domain with self-aggregated convection. Multiple equilibria refers to a steady state which either exhibits a completely dry troposphere or persistent precipitating deep convection under identical forcing conditions. The large scale circulation is parameterized based on the assumption that horizontal gradients in temperature are small in the tropics. Understanding the mechanisms which permit multiple equilibria on small domains is a computationally economic approach to understanding self-aggregation. We show how multiple equilibria depend on SSTs, and thus provide insight to self-aggregation in a warming climate. This work supported by NSF grant number AGS-1056254

  5. Adaptive strategies and life history characteristics in a warming climate: salmon in the Arctic?

    USGS Publications Warehouse

    Nielsen, Jennifer L.; Ruggerone, Gregory T.; Zimmerman, Christian E.

    2013-01-01

    In the warming Arctic, aquatic habitats are in flux and salmon are exploring their options. Adult Pacific salmon, including sockeye (Oncorhynchus nerka), coho (O. kisutch), Chinook (O. tshawytscha), pink (O. gorbuscha) and chum (O. keta) have been captured throughout the Arctic. Pink and chum salmon are the most common species found in the Arctic today. These species are less dependent on freshwater habitats as juveniles and grow quickly in marine habitats. Putative spawning populations are rare in the North American Arctic and limited to pink salmon in drainages north of Point Hope, Alaska, chum salmon spawning rivers draining to the northwestern Beaufort Sea, and small populations of chum and pink salmon in Canada’s Mackenzie River. Pacific salmon have colonized several large river basins draining to the Kara, Laptev and East Siberian seas in the Russian Arctic. These populations probably developed from hatchery supplementation efforts in the 1960’s. Hundreds of populations of Arctic Atlantic salmon (Salmo salar) are found in Russia, Norway and Finland. Atlantic salmon have extended their range eastward as far as the Kara Sea in central Russian. A small native population of Atlantic salmon is found in Canada’s Ungava Bay. The northern tip of Quebec seems to be an Atlantic salmon migration barrier for other North American stocks. Compatibility between life history requirements and ecological conditions are prerequisite for salmon colonizing Arctic habitats. Broad-scale predictive models of climate change in the Arctic give little information about feedback processes contributing to local conditions, especially in freshwater systems. This paper reviews the recent history of salmon in the Arctic and explores various patterns of climate change that may influence range expansions and future sustainability of salmon in Arctic habitats. A summary of the research needs that will allow informed expectation of further Arctic colonization by salmon is given.

  6. Paleoclimate diagnostics: consistent large-scale temperature responses in warm and cold climates

    NASA Astrophysics Data System (ADS)

    Izumi, Kenji; Bartlein, Patrick; Harrison, Sandy

    2015-04-01

    The CMIP5 model simulations of the large-scale temperature responses to increased raditative forcing include enhanced land-ocean contrast, stronger response at higher latitudes than in the tropics, and differential responses in warm and cool season climates to uniform forcing. Here we show that these patterns are also characteristic of CMIP5 model simulations of past climates. The differences in the responses over land as opposed to over the ocean, between high and low latitudes, and between summer and winter are remarkably consistent (proportional and nearly linear) across simulations of both cold and warm climates. Similar patterns also appear in historical observations and paleoclimatic reconstructions, implying that such responses are characteristic features of the climate system and not simple model artifacts, thereby increasing our confidence in the ability of climate models to correctly simulate different climatic states. We also show the possibility that a small set of common mechanisms control these large-scale responses of the climate system across multiple states.

  7. Increases in Flood Magnitudes in California Under Warming Climates

    NASA Astrophysics Data System (ADS)

    Das, T.; Maurer, E. P.; Pierce, D. W.; Dettinger, M. D.; Cayan, D.; Munevar, A.

    2012-12-01

    Downscaled and hydrologically modeled projections from an ensemble of sixteen Global Climate Models suggest that flooding may become more intense on the western slopes of the Sierra Nevada mountains, the primary source for California's managed water system. By the end of the 21st century, all 32 climate projections yield larger floods with return periods ranging 2 to 50 years for both the moderate elevation Northern Sierra Nevada and higher elevation Southern Sierra Nevada, regardless of the direction of change in mean precipitation. By end of century, discharges from the Northern Sierra Nevada with 50-year return periods increase by 30 to 90 percent depending on climate model and emission scenario, compared to historical values. Corresponding flood flows from the Southern Sierra increase by 50 to 100 percent. The increases in simulated 50 year flood flows are larger (at 95% confidence level) than would be expected due to natural variability by as early as 2035 for the higher (A2) greenhouse gas emission scenario.

  8. A brief history of climate - the northern seas from the Last Glacial Maximum to global warming

    NASA Astrophysics Data System (ADS)

    Eldevik, Tor; Risebrobakken, Bjørg; Bjune, Anne E.; Andersson, Carin; Birks, H. John B.; Dokken, Trond M.; Drange, Helge; Glessmer, Mirjam S.; Li, Camille; Nilsen, Jan Even Ø.; Otterå, Odd Helge; Richter, Kristin; Skagseth, Øystein

    2014-12-01

    The understanding of climate and climate change is fundamentally concerned with two things: a well-defined and sufficiently complete climate record to be explained, for example of observed temperature, and a relevant mechanistic framework for making closed and consistent inferences concerning cause-and-effect. This is the case for understanding observed climate, as it is the case for historical climate as reconstructed from proxy data and future climate as projected by models. The present study offers a holistic description of northern maritime climate - from the Last Glacial Maximum through to the projected global warming of the 21st century - in this context. It includes the compilation of the most complete temperature record for Norway and the Norwegian Sea to date based on the synthesis of available terrestrial and marine paleoclimate reconstructions into continuous times series, and their continuation into modern and future climate with the instrumental record and a model projection. The scientific literature on a variable northern climate is reviewed against this background, and with a particular emphasis on the role of the Norwegian Atlantic Current - the Gulf Stream's extension towards the Arctic. This includes the introduction of an explicit and relatively simple diagnostic relation to quantify the change in ocean circulation consistent with reconstructed ocean temperatures. It is found that maritime climate and the strength of the Norwegian Atlantic Current are closely related throughout the record. The nature of the relation is however qualitatively different as one progresses from the past, through the present, and into the future.

  9. McMurdo Dry Valleys Climate Response to Plio-Pleistocene Warm Interglacial Climate Forcing

    NASA Astrophysics Data System (ADS)

    Kowalewski, D. E.; Deconto, R.; Seth, A.; Pollard, D.

    2010-12-01

    The Antarctic Drilling Program recovered high quality Neogene sediment cores off of the coast of Ross Island recording a series of ice-contact, ice-proximal, ice-distal and marine facies suggesting grounding line migration along the sea floor. Chronology control of the core places glacial variability consistent with ~41 kyr orbital forcing. The marine facies suggests episodes of open-water conditions and elevated sea-surface temperatures in McMurdo Sound and the Ross Sea during the Pliocene. Recent Antarctic ice sheet modeling efforts have supported episodic retreat of the sea ice and possibly a frequent collapse of the West Antarctic Ice Sheet (WAIS) during the warmest intervals of the Pliocene-Pleistocene. Such repeated reduction in the Antarctic Ice Sheets occurs at a time when terrestrial records from near-by McMurdo Dry Valleys call for enduring hyper-arid cold desert conditions since the mid-to early Miocene. To assess whether hyper-arid cold desert climate could exist at high elevations within the McMurdo Dry Valleys during episodes of a diminished ice sheet (and near-by open water conditions), or if in fact these conditions are mutually exclusive, we simulated both present day (for validation) and paleo-climate conditions for Antarctic using a high resolution Regional Climate Model (RegCM3) nested within a medium resolution Global Climate Model (GCM) to predict paleo-climate as a function of ice sheet variability. RegCM3 simulations for paleo-conditions focused on the response of the Ross Sea sector to 1) orbital changes consistent with peak austral summer warmth, 2) reduction of ice shelves including the loss of the Ross and Filchner-Ronne Ice Shelves, 3) higher than modern carbon dioxide concentrations (400 - 800 ppmv) and 4) a highly diminished WAIS as predicted by the ice-sheet model. Results show mean atmospheric temperatures in the McMurdo Dry Valleys are most sensitive to loss of sea ice in McMurdo Sound / Ross Sea. If we assume a loss of marine grounded ice and remove the Antarctic ice shelves the mean atmospheric temperatures in the McMurdo Dry Valleys increases; model results suggest temperatures were 2.78°C and 2.38°C warmer than today at the coast and inland respectively although the rise in atmospheric temperatures during the summer months is typically of a smaller magnitude compared to the temperature rise predicted for the winter months. As expected the model showed warmer mean atmospheric temperatures with elevated levels of CO2. Precipitation also increased in the McMurdo Dry Valleys with increasing values of CO2. Initial model results for simulations run with a diminished WAIS predict increased atmospheric temperatures for most of the continent; temperature increase within the Transantarctic Mountains and McMurdo Dry Valleys is below the mean rise in Antarctic temperature for this simulation.

  10. Climate Warming and 21st-Century Drought in Southwestern North America

    NASA Astrophysics Data System (ADS)

    MacDonald, Glen M.; Stahle, David W.; Diaz, Jose Villanueva; Beer, Nicholas; Busby, Simon J.; Cerano-Paredes, Julian; Cole, Julie E.; Cook, Edward R.; Endfield, Georgina; Gutierrez-Garcia, Genaro; Hall, Beth; Magana, Victor; Meko, David M.; Méndez-Pérez, Matias; Sauchyn, David J.; Watson, Emma; Woodhouse, Connie A.

    2008-02-01

    Since 2000, southwestern North America has experienced widespread drought. Lakes Powell and Mead are now at less than 50% of their reservoir capacity, and drought or fire-related states of emergency were declared this past summer by governors in six western states. As with other prolonged droughts, such as the Dust Bowl during the 1930s, aridity has at times extended from northern Mexico to the southern Canadian prairies. A synthesis of climatological and paleoclimatological studies suggests that a transition to a more arid climate may be occurring due to global warming, with the prospect of sustained droughts being exacerbated by the potential reaction of the Pacific Ocean to warming.

  11. Possible climate warming effects on vegetation, forests, biotic (insect, pathogene) disturbances and agriculture in Central Siberia for 1960- 2050

    NASA Astrophysics Data System (ADS)

    Tchebakova, N. M.; Parfenova, E. I.; Soja, A. J.; Lysanova, G. I.; Baranchikov, Y. N.; Kuzmina, N. A.

    2012-04-01

    Regional Siberian studies have already registered climate warming over the last half a century (1960-2010). Our analysis showed that winters are already 2-3°C warmer in the north and 1-2°C warmer in the south by 2010. Summer temperatures increased by 1°C in the north and by 1-2°C in the south. Change in precipitation is more complicated, increasing on average 10% in middle latitudes and decreasing 10-20% in the south, promoting local drying in already dry landscapes. Our goal was to summarize results of research we have done for the last decade in the context of climate warming and its consequences for biosystems in Central Siberia. We modeled climate change effects on vegetation shifts, on forest composition and agriculture change, on the insect Siberian moth (Dendrolimus suprans sibiricus Tschetv) and pathogene (Lophodermium pinastri Chev) ranges in Central Siberia for a century (1960-2050) based on historical climate data and GCM-predicted data. Principal results are: In the warmer and drier climate projected by these scenarios, Siberian forests are predicted to decrease and shift northwards and forest-steppe and steppe ecosystems are predicted to dominate over 50% of central Siberia due to the dryer climate by 2080. Permafrost is not predicted to thaw deep enough to sustain dark (Pinus sibirica, Abies sibirica, and Picea obovata) taiga. Over eastern Siberia, larch (Larix dahurica) taiga is predicted to continue to be the dominant zonobiome because of its ability to withstand continuous permafrost. The model also predicts new temperate broadleaf forest and forest-steppe habitats; At least half of central Siberia is predicted to be climatically suitable for agriculture at the end of the century although potential croplands would be limited by the availability of suitable soils agriculture in central Siberia would likely benefit from climate warming Crop production may twofold increase as climate warms during the century; traditional crops (grain, potato, maize for silage) could be gradually shifted as far as 500 km from the south northwards (about 50-70 km per decade) and new crops (maize for grain, apricot, grape, gourds) may be introduced in the very south depending on winter conditions and would necessitate irrigation in a drier 2080 climate; The environment for the Siberian moth may considerably shrink in the future leaving suitable habitats only in highlands of mountains and the north of Eurasia. The moth habitats also depend on migration rates of tree species Larix spp., Abies sibirica, and Pinus sibirica being main food resources. Siberian moth may not be considered as a threat in climates with mild winter because larvae require continuos continental type winters. Needle-cast of Pinus sylvestris caused by Lophodermium pinastri Chev. was found to be strongly related to precipation including snow depth. In a predicted dryer climate, it would shift northwards followed sufficient water.

  12. Potential Impacts of Climate Warming on Water Supply Reliability in the Tuolumne and Merced River Basins, California

    PubMed Central

    Kiparsky, Michael; Joyce, Brian; Purkey, David; Young, Charles

    2014-01-01

    We present an integrated hydrology/water operations simulation model of the Tuolumne and Merced River Basins, California, using the Water Evaluation and Planning (WEAP) platform. The model represents hydrology as well as water operations, which together influence water supplied for agricultural, urban, and environmental uses. The model is developed for impacts assessment using scenarios for climate change and other drivers of water system behavior. In this paper, we describe the model structure, its representation of historical streamflow, agricultural and urban water demands, and water operations. We describe projected impacts of climate change on hydrology and water supply to the major irrigation districts in the area, using uniform 2°C, 4°C, and 6°C increases applied to climate inputs from the calibration period. Consistent with other studies, we find that the timing of hydrology shifts earlier in the water year in response to temperature warming (5–21 days). The integrated agricultural model responds with increased water demands 2°C (1.4–2.0%), 4°C (2.8–3.9%), and 6°C (4.2–5.8%). In this sensitivity analysis, the combination of altered hydrology and increased demands results in decreased reliability of surface water supplied for agricultural purposes, with modeled quantity-based reliability metrics decreasing from a range of 0.84–0.90 under historical conditions to 0.75–0.79 under 6°C warming scenario. PMID:24465455

  13. How Will Climate Warming Affect Non-Native Pumpkinseed Lepomis gibbosus Populations in the U.K.?

    PubMed Central

    Zi?ba, Grzegorz; Fox, Michael G.; Copp, Gordon H.

    2015-01-01

    Of the non-native fishes introduced to the U.K., the pumpkinseed is one of six species predicted to benefit from the forecasted climate warming conditions. To demonstrate the potential response of adults and their progeny to a water temperature increase, investigations of parental pumpkinseed acclimatization, reproduction and YOY over-wintering were carried out in outdoor experimental ponds under ambient and elevated water temperature regimes. No temperature effects were observed on either adult survivorship and growth, and none of the assessed reproductive activity variables (total spawning time, spawning season length, number of spawning bouts) appeared to be responsible for the large differences observed in progeny number and biomass. However, it was demonstrated in a previous study [Zi?ba G. et al., 2010] that adults in the heated ponds began spawning earlier than those of the ambient ponds. Ambient ponds produced 2.8× more progeny than the heated ponds, but these progeny were significantly smaller, probably due to their late hatching date, and subsequently suffered very high mortality over the first winter. Pumpkinseed in the U.K. will clearly benefit from climate warming through earlier seasonal reproduction, resulting in larger progeny going into winter, and as a result, higher over-winter survivorship would be expected relative to that which occurs under the present climatic regime. PMID:26302021

  14. The influence of Greenland melt water on climate during past and future warm periods: a model study

    NASA Astrophysics Data System (ADS)

    Blaschek, Michael; Bakker, Pepijn; Renssen, Hans

    2013-04-01

    "Can past climates teach us something about the future?" Under this general question of interest to most palaeoclimate-modeller we specified it more to "Can past changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC) related to melt water from the Greenland Ice Sheet (GIS) teach us something about future changes in the AMOC forced by predicted partial melting of the GIS?" To address this question, we developed a series of sensitivity experiments with the global atmosphere-ocean-sea-ice model LOVECLIM to better understand the relationship between the strength of the Atlantic Meridional Overturning Circulation (AMOC) and Greenland Ice Sheet (GIS) melt over the last and present interglacials (the Eemian and the Holocene, respectively) and put these into perspective of future greenhouse gas emission scenarios. In terms of radiative forcing, future emission scenarios are different from past orbitally-forced warm periods, as past insolation varied per season and per latitude, whereas radiative forcing due to future greenhouse gas emissions has no seasonal component (i.e. it is an annual forcing) and shows little variation per latitude. However, the two can be compared when we consider the radiative forcing regimes of the different considered warm climates, by focusing on the energy that is potentially available from radiative forcing to melt the GIS. In a similar approach, Swingedouw et al. (2009) have shown in simulations with an AOGCM that the AMOC sensitivity relates non-linear to freshwater input and that under Last Glacial Maximum (LGM) conditions the climate is more sensitive compared to warmer climates. They conclude that different climatic conditions share similar patterns in response and that past climates are useful for models to evaluate their abilities in reproducing past events. The authors encourage further model sensitivity testing to gain a better understanding of this highly important question. In order to test this approach we performed a series of experiments in which we applied different versions of our model that differ in the sensitivity to freshwater forcing. These experiments cover all three periods considered: the Eemian, the Holocene and the 21st Century. We used different amounts of GIS melt fluxes that correspond to a wide range of changes in percent from modern-day ice sheet volume, ranging from as little as 5% to 100%. The GIS extent and topography was kept at present-day conditions. The future greenhouse gas emissions are taken from the Representative Concentration Pathways (Meinshausen et al. 2011), the new scenarios for climate change research. Our first results suggest that the warmer Eemian and the less warm Holocene test cases have a quite linear relationship in terms of AMOC sensitivity to GIS melt. In all our sensitivity experiments the Eemian is more sensitive to freshwater forcing than the Holocene. Meinshausen, M.; Smith, S.; Calvin, K.; Daniel, J.; Kainuma, M.; Lamarque, J.-F.; Matsumoto, K.; Montzka, S.; Raper, S.; Riahi, K.; Thomson, A.; Velders, G. & van Vuuren, D.,The RCP greenhouse gas concentrations and their extensions from 1765 to 2300, Climatic Change, Springer Netherlands, 2011, 109, 213-241 Swingedouw, D.; Mignot, J.; Braconnot, P.; Mosquet, E.; Kageyama, M. & Alkama, R.,Impact of Freshwater Release in the North Atlantic under Different Climate Conditions in an OAGCM, J. Climate, Journal of Climate, American Meteorological Society, 2009, 22, 6377-6403

  15. Warming-induced increase in aerosol number concentration likely to moderate climate change

    NASA Astrophysics Data System (ADS)

    Paasonen, Pauli; Asmi, Ari; Petäjä, Tuukka; Kajos, Maija K.; Äijälä, Mikko; Junninen, Heikki; Holst, Thomas; Abbatt, Jonathan P. D.; Arneth, Almut; Birmili, Wolfram; van der Gon, Hugo Denier; Hamed, Amar; Hoffer, András; Laakso, Lauri; Laaksonen, Ari; Richard Leaitch, W.; Plass-Dülmer, Christian; Pryor, Sara C.; Räisänen, Petri; Swietlicki, Erik; Wiedensohler, Alfred; Worsnop, Douglas R.; Kerminen, Veli-Matti; Kulmala, Markku

    2013-06-01

    Atmospheric aerosol particles influence the climate system directly by scattering and absorbing solar radiation, and indirectly by acting as cloud condensation nuclei. Apart from black carbon aerosol, aerosols cause a negative radiative forcing at the top of the atmosphere and substantially mitigate the warming caused by greenhouse gases. In the future, tightening of controls on anthropogenic aerosol and precursor vapour emissions to achieve higher air quality may weaken this beneficial effect. Natural aerosols, too, might affect future warming. Here we analyse long-term observations of concentrations and compositions of aerosol particles and their biogenic precursor vapours in continental mid- and high-latitude environments. We use measurements of particle number size distribution together with boundary layer heights derived from reanalysis data to show that the boundary layer burden of cloud condensation nuclei increases exponentially with temperature. Our results confirm a negative feedback mechanism between the continental biosphere, aerosols and climate: aerosol cooling effects are strengthened by rising biogenic organic vapour emissions in response to warming, which in turn enhance condensation on particles and their growth to the size of cloud condensation nuclei. This natural growth mechanism produces roughly 50% of particles at the size of cloud condensation nuclei across Europe. We conclude that biosphere-atmosphere interactions are crucial for aerosol climate effects and can significantly influence the effects of anthropogenic aerosol emission controls, both on climate and air quality.

  16. Climate warming could reduce runoff significantly in New England, USA

    USGS Publications Warehouse

    Huntington, T.G.

    2003-01-01

    The relation between mean annual temperature (MAT), mean annual precipitation (MAP) and evapotranspiration (ET) for 38 forested watersheds was determined to evaluate the potential increase in ET and resulting decrease in stream runoff that could occur following climate change and lengthening of the growing season. The watersheds were all predominantly forested and were located in eastern North America, along a gradient in MAT from 3.5??C in New Brunswick, CA, to 19.8??C in northern Florida. Regression analysis for MAT versus ET indicated that along this gradient ET increased at a rate of 2.85 cm??C-1 increase in MAT (??0.96 cm??C-1, 95% confidence limits). General circulation models (GCM) using current mid-range emission scenarios project global MAT to increase by about 3??C during the 21st century. The inferred, potential, reduction in annual runoff associated with a 3??C increase in MAT for a representative small coastal basin and an inland mountainous basin in New England would be 11-13%. Percentage reductions in average daily runoff could be substantially larger during the months of lowest flows (July-September). The largest absolute reductions in runoff are likely to be during April and May with smaller reduction in the fall. This seasonal pattern of reduction in runoff is consistent with lengthening of the growing season and an increase in the ratio of rain to snow. Future increases in water use efficiency (WUE), precipitation, and cloudiness could mitigate part or all of this reduction in runoff but the full effects of changing climate on WUE remain quite uncertain as do future trends in precipitation and cloudiness.

  17. Warming Ocean Conditions Relate to Increased Trophic Requirements of Threatened and Endangered Salmon

    PubMed Central

    Daly, Elizabeth A.; Brodeur, Richard D.

    2015-01-01

    The trophic habits, size and condition of yearling Chinook salmon (Oncorhynchus tshawytscha) caught early in their marine residence were examined during 19 survey years (1981–1985; 1998–2011). Juvenile salmon consumed distinct highly piscivorous diets in cold and warm ocean regimes with major differences between ocean regimes driven by changes in consumption of juvenile rockfishes, followed by several other fish prey, adult euphausiids and decapod larvae. Notable, Chinook salmon consumed 30% more food in the warm versus cold ocean regime in both May and June. Additionally, there were about 30% fewer empty stomachs in the warm ocean regime in May, and 10% fewer in warm June periods. The total prey energy density consumed during the warmer ocean regime was also significantly higher than in cold. Chinook salmon had lower condition factor and were smaller in fork length during the warm ocean regime, and were longer and heavier for their size during the cold ocean regime. The significant increase in foraging during the warm ocean regime occurred concurrently with lower available prey biomass. Adult return rates of juvenile Chinook salmon that entered the ocean during a warm ocean regime were lower. Notably, our long term data set contradicts the long held assertion that juvenile salmon eat less in a warm ocean regime when low growth and survival is observed, and when available prey are reduced. Comparing diet changes between decades under variable ocean conditions may assist us in understanding the effects of projected warming ocean regimes on juvenile Chinook salmon and their survival in the ocean environment. Bioenergetically, the salmon appear to require more food resources during warm ocean regimes. PMID:26675673

  18. 24 CFR 3285.404 - Severe climatic conditions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Severe climatic conditions. 3285.404 Section 3285.404 Housing...Against Wind § 3285.404 Severe climatic conditions. In frost-susceptible soil locations, ground anchor augers must be...

  19. The influence of climate change and the timing of stratospheric warmings on Arctic ozone depletion

    SciTech Connect

    Austin, J.; Butchart, N.

    1994-01-20

    A three-dimensional model is presented to evaluate the influence of climatic change and increased carbon dioxide concentrations on ozone depletion in the Arctic region. Satellite data showing the time of stratospheric warmings during the winters of 1979-1992 is used in a series of idealized experiments where the timing of the warmings is varied by using different geopotential wave amplitudes. Results of the experiments indicate that for doubled atmospheric carbon dioxide levels, an ozone hole in the Arctic is more likely to develop during years where late stratospheric warming has occurred after a relatively quiescent winter. The validity of this model is dependent on the future composition and temperature of the stratosphere. 43 refs., 21 figs.

  20. Hamburg 2K: Climate modeling and downscaling for Hamburg, Germany under a 2 K global warming scenario

    NASA Astrophysics Data System (ADS)

    Flagg, D. D.; Grawe, D.; Daneke, C.; Hoffmann, P.; Jacob, D.; Kirschner, P.; Kriegsmann, A.; Linde, M.; Mayer, B.; O'Driscoll, K. T.; Pohlmann, T.; Schlünzen, K. H.; Schoetter, R.; Teichert, W.; Zorita, E.

    2011-12-01

    The European Union has established a 2 K warming of average annual global surface temperature above pre-industrial levels as a target to avoid disruptive climate change. The Hamburg 2K project seeks to model the climate of Hamburg, Germany subject to this target warming by the end of the 21st century. A general circulation model (ECHAM5) with a greenhouse gas scenario consistent with this target (E1) provides a source for dynamical and statistical-dynamical model downscaling at the regional scale, using the Regional Model (REMO), and at the mesoscale, using the Mesoscale Transport and fluid (Stream) Model (METRAS). Regional scale model estimates provide forcing for off-line modeling of the North Sea circulation with the Hamburg Shelf-Ocean Model (HAMSOM). This presentation concentrates on the urban climate component of the 2K scenario. The approach quantifies the projected change in both the meteorology and the urban development. The modeling strategy allows for a discrete diagnosis of each contribution. For the meteorology, the project identifies an urban climate change signal between the late 20th and late 21st centuries using a statistical-dynamical downscaling technique. Cluster analysis of multiple REMO realizations generates a series of archetypical synoptic conditions, a.k.a., weather types. The frequency change of these weather types between present and future climate yields a climate change signal. The potential for distinctively new weather types in the future climate is also investigated. Regional weather types provide the forcing for simulations with METRAS at 1 km resolution. These simulations provide further assessment of urban climate change at a scale more sensitive to the heterogeneous urban surface. Some initial METRAS modeling results will be presented here. For the urban development, the METRAS model simulations benefit from a detailed surface cover map including over 50 classes of natural and artificial surfaces tailored specifically for Hamburg. The simulations of future climate incorporate estimates of future surface cover. Evaluation of current municipal construction plans helps quantify trends in building density and change in unsealed surface cover. An off-line urban planning model tuned for the 2K scenario incorporates these plans into its parameterizations and assists in deriving a future surface cover map of Hamburg.

  1. Enhanced Climatic Warming in the Tibetan Plateau Due to Double CO2: A Model Study

    NASA Technical Reports Server (NTRS)

    Chen, Baode; Chao, Winston C.; Liu, Xiao-Dong; Lau, William K. M. (Technical Monitor)

    2001-01-01

    The NCAR (National Center for Atmospheric Research) regional climate model (RegCM2) with time-dependent lateral meteorological fields provided by a 130-year transient increasing CO2 simulation of the NCAR Climate System Model (CSM) has been used to investigate the mechanism of enhanced ground temperature warming over the TP (Tibetan Plateau). From our model results, a remarkable tendency of warming increasing with elevation is found for the winter season, and elevation dependency of warming is not clearly recognized in the summer season. This simulated feature of elevation dependency of ground temperature is consistent with observations. Based on an analysis of surface energy budget, the short wave solar radiation absorbed at the surface plus downward long wave flux reaching the surface shows a strong elevation dependency, and is mostly responsible for enhanced surface warming over the TP. At lower elevations, the precipitation forced by topography is enhanced due to an increase in water vapor supply resulted from a warming in the atmosphere induced by doubling CO2. This precipitation enhancement must be associated with an increase in clouds, which results in a decline in solar flux reaching surface. At higher elevations, large snow depletion is detected in the 2xCO2run. It leads to a decrease in albedo, therefore more solar flux is absorbed at the surface. On the other hand, much more uniform increase in downward long wave flux reaching the surface is found. The combination of these effects (i.e. decrease in solar flux at lower elevations, increase in solar flux at higher elevation and more uniform increase in downward long wave flux) results in elevation dependency of enhanced ground temperature warming over the TP.

  2. Climate change, global warming and coral reefs: modelling the effects of temperature.

    PubMed

    Crabbe, M James C

    2008-10-01

    Climate change and global warming have severe consequences for the survival of scleractinian (reef-building) corals and their associated ecosystems. This review summarizes recent literature on the influence of temperature on coral growth, coral bleaching, and modelling the effects of high temperature on corals. Satellite-based sea surface temperature (SST) and coral bleaching information available on the internet is an important tool in monitoring and modelling coral responses to temperature. Within the narrow temperature range for coral growth, corals can respond to rate of temperature change as well as to temperature per se. We need to continue to develop models of how non-steady-state processes such as global warming and climate change will affect coral reefs. PMID:18565794

  3. Assessment of the effects of climate warming on Great Lakes basin fishes

    SciTech Connect

    Meisner, J.D.; Goodier, J.L.; Regier, H.A.; Shuter, B.J.; Christie, W.J.

    1987-01-01

    The authors combine information on the influence of temperature on the physiology and ecology of fishes with information on the interrelationships between climate and physical limnology for an initial assessment of the impact of future climate warming on fishes and their habitats in the Great Lakes basin. The predicted increase in mean annual air temperature of 3.2-4.8 /sup 0/C is not expected to extirpate fish taxa in the basin. Habitat warming in streams and lakes will likely shrink extant populations of salmonines and coregonines through reductions in preferred thermal habitat and allow range extensions of cyprinids, esocids, centrarchids, and ictalurids. Competition for optimal thermal space within thermal niches will increase, resulting in changes in community composition. Relatively rapid changes in water level would adversely affect the structure of wetlands and littoral areas, reducing their efficacy as spawning and nursery areas. Changes in fisheries yields of preferred species are expected.

  4. Impact of a global warming on biospheric sources of methane and its climatic consequences

    NASA Technical Reports Server (NTRS)

    Hameed, S.; Cess, R. D.

    1980-01-01

    Most of atmospheric methane originates by bacterial processes in anaerobic environments within the soil which are found to become more productive with increases in ambient temperature. A warming of climate, due to increasing levels of industrial gases resulting from fossil fuel burning, is thus likely to increase methane abundance within the atmosphere. This may lead to further heating of the atmosphere, since both methane and ozone (which is generated in the troposphere from reactions of methane) have greenhouse effects. This feedback mechanism has been explored with the use of a coupled climate-chemical model of the troposphere, by the calculation of the impact of the predicted global warming due to increased emissions of carbon dioxide and other industrial gases on the biospheric sources of methane.

  5. Warm-water decapods and the trophic amplification of climate in the North Sea

    PubMed Central

    Lindley, J. A.; Beaugrand, G.; Luczak, C.; Dewarumez, J.-M.; Kirby, R. R.

    2010-01-01

    A long-term time series of plankton and benthic records in the North Sea indicates an increase in decapods and a decline in their prey species that include bivalves and flatfish recruits. Here, we show that in the southern North Sea the proportion of decapods to bivalves doubled following a temperature-driven, abrupt ecosystem shift during the 1980s. Analysis of decapod larvae in the plankton reveals a greater presence and spatial extent of warm-water species where the increase in decapods is greatest. These changes paralleled the arrival of new species such as the warm-water swimming crab Polybius henslowii now found in the southern North Sea. We suggest that climate-induced changes among North Sea decapods have played an important role in the trophic amplification of a climate signal and in the development of the new North Sea dynamic regime. PMID:20554562

  6. Assessment of thermal change in cold avalanching glaciers in relation to climate warming

    NASA Astrophysics Data System (ADS)

    Gilbert, A.; Vincent, C.; Gagliardini, O.; Krug, J.; Berthier, E.

    2015-08-01

    High-elevation glaciers covered by cold firn are undergoing substantial warming in response to ongoing climate change. This warming is affecting the ice/rock interface temperature, the primary driver of avalanching glacier instability on steep slopes. Prediction of future potential instability therefore requires appropriate modeling of the thermal evolution of these glaciers. Application of a state-of-the-art model to a glacier in the French Alps (Taconnaz) has provided the first evaluation of the temperature evolution of a cold hanging glacier through this century. Our observations and three-dimensional modeling of the glacier response (velocity, thickness, temperature, density, and water content) to climate change indicate that Taconnaz glacier will become temperate and potentially unstable over a large area by the end of the 21st century. The risk induced by this glacier hazard is high for the populated region below and makes observation and modeling of such glaciers a priority.

  7. Warming climate extends dryness-controlled areas of terrestrial carbon sequestration

    PubMed Central

    Yi, Chuixiang; Wei, Suhua; Hendrey, George

    2014-01-01

    At biome-scale, terrestrial carbon uptake is controlled mainly by weather variability. Observational data from a global monitoring network indicate that the sensitivity of terrestrial carbon sequestration to mean annual temperature (T) breaks down at a threshold value of 16°C, above which terrestrial CO2 fluxes are controlled by dryness rather than temperature. Here we show that since 1948 warming climate has moved the 16°C T latitudinal belt poleward. Land surface area with T > 16°C and now subject to dryness control rather than temperature as the regulator of carbon uptake has increased by 6% and is expected to increase by at least another 8% by 2050. Most of the land area subjected to this warming is arid or semiarid with ecosystems that are highly vulnerable to drought and land degradation. In areas now dryness-controlled, net carbon uptake is ~27% lower than in areas in which both temperature and dryness (T < 16°C) regulate plant productivity. This warming-induced extension of dryness-controlled areas may be triggering a positive feedback accelerating global warming. Continued increases in land area with T > 16°C has implications not only for positive feedback on climate change, but also for ecosystem integrity and land cover, particularly for pastoral populations in marginal lands. PMID:24980649

  8. The ice-core record - Climate sensitivity and future greenhouse warming

    NASA Technical Reports Server (NTRS)

    Lorius, C.; Raynaud, D.; Jouzel, J.; Hansen, J.; Le Treut, H.

    1990-01-01

    The prediction of future greenhouse-gas-warming depends critically on the sensitivity of earth's climate to increasing atmospheric concentrations of these gases. Data from cores drilled in polar ice sheets show a remarkable correlation between past glacial-interglacial temperature changes and the inferred atmospheric concentration of gases such as carbon dioxide and methane. These and other palaeoclimate data are used to assess the role of greenhouse gases in explaining past global climate change, and the validity of models predicting the effect of increasing concentrations of such gases in the atmosphere.

  9. Formability analysis of austenitic stainless steel-304 under warm conditions

    NASA Astrophysics Data System (ADS)

    Lade, Jayahari; Singh, Swadesh Kumar; Banoth, Balu Naik; Gupta, Amit Kumar

    2013-12-01

    A warm deep drawing process of austenitic stainless steel-304 (ASS-304) of circular blanks with coupled ther mal analysis is studied in this article. 65 mm blanks were deep drawn at different temperatures and thickness distribution is experimentally measured after cutting the drawn component into two halves. The process is simulated using explicit fin ite element code LS-DYNA. A Barlat 3 parameter model is used in the simulation, as the material is anisotropic up to 30 0°C. Material properties for the simulation are determined at different temperatures using a 5 T UTM coupled with a furn ace. In this analysis constant punch speed and variable blank holder force (BHF) is applied to draw cups without wrinkle.

  10. 500-year climate cycles stacking of recent centennial warming documented in an East Asian pollen record

    PubMed Central

    Xu, Deke; Lu, Houyuan; Chu, Guoqiang; Wu, Naiqin; Shen, Caiming; Wang, Can; Mao, Limi

    2014-01-01

    Here we presented a high-resolution 5350-year pollen record from a maar annually laminated lake in East Asia (EA). Pollen record reflected the dynamics of vertical vegetation zones and temperature change. Spectral analysis on pollen percentages/concentrations of Pinus and Quercus, and a temperature proxy, revealed ~500-year quasi-periodic cold-warm fluctuations during the past 5350 years. This ~500-year cyclic climate change occurred in EA during the mid-late Holocene and even the last 150 years dominated by anthropogenic forcing. It was almost in phase with a ~500-year periodic change in solar activity and Greenland temperature change, suggesting that ~500-year small variations in solar output played a prominent role in the mid-late Holocene climate dynamics in EA, linked to high latitude climate system. Its last warm phase might terminate in the next several decades to enter another ~250-year cool phase, and thus this future centennial cyclic temperature minimum could partially slow down man-made global warming. PMID:24402348

  11. 500-year climate cycles stacking of recent centennial warming documented in an East Asian pollen record.

    PubMed

    Xu, Deke; Lu, Houyuan; Chu, Guoqiang; Wu, Naiqin; Shen, Caiming; Wang, Can; Mao, Limi

    2014-01-01

    Here we presented a high-resolution 5350-year pollen record from a maar annually laminated lake in East Asia (EA). Pollen record reflected the dynamics of vertical vegetation zones and temperature change. Spectral analysis on pollen percentages/concentrations of Pinus and Quercus, and a temperature proxy, revealed ~500-year quasi-periodic cold-warm fluctuations during the past 5350 years. This ~500-year cyclic climate change occurred in EA during the mid-late Holocene and even the last 150 years dominated by anthropogenic forcing. It was almost in phase with a ~500-year periodic change in solar activity and Greenland temperature change, suggesting that ~500-year small variations in solar output played a prominent role in the mid-late Holocene climate dynamics in EA, linked to high latitude climate system. Its last warm phase might terminate in the next several decades to enter another ~250-year cool phase, and thus this future centennial cyclic temperature minimum could partially slow down man-made global warming. PMID:24402348

  12. Ocean Heat Transport and Water Vapor Greenhouse in a Warm Equable Climate: A New Look at the Low Gradient Paradox

    E-print Network

    Rose, Brian E. J.

    The authors study the role of ocean heat transport (OHT) in the maintenance of a warm, equable, ice-free climate. An ensemble of idealized aquaplanet GCM calculations is used to assess the equilibrium sensitivity of global ...

  13. The dynamics of the Earth's climate and the global-warming debate are complex, to say the least. NJIT

    E-print Network

    Haimovich, Alexander

    The dynamics of the Earth's climate and the global- warming debate are complex, to say the least with significant implications for further study of global warming. Weinstein: What led you to study the Earth years. We've also applied to the Keck Foundation for money to build a global network of eight automated

  14. Soil Warming Alters the Nitrogen Cycle: Ecosystem Implications and Feedbacks to the Climate System

    NASA Astrophysics Data System (ADS)

    Butler, S. M.; Melillo, J. M.; Johnson, J. E.; Mohan, J. E.; Steudler, P. A.; Bowles, F. P.

    2008-12-01

    Increases in soil temperatures associated with global warming have the potential to accelerate nitrogen turnover in soils, which could alter other biogeochemical processes and eventually affect the structure of these forests. Over the past five years we have been studying soil and plant responses to soil warming in large plots in a deciduous stand at Harvard Forest in central Massachusetts. We have heated the soil 5°C above ambient and measured nitrogen cycling parameters including in situ net nitrogen mineralization and nitrification, nitrogen leaching and nitrous oxide (N2O) fluxes. We have also measured various aspects of the carbon cycle including soil respiration and carbon accumulation in vegetation. Over the first five years of the study, we observed a mean annual increase in the net nitrogen mineralized in the warmed plot of 23.8 kg N ha-1. While nitrification rates were low throughout the five years in the control plot, they increased in the warmed plot to account for over 25% of the total net nitrogen mineralized in year five. The increase in nitrogen mineralization stimulated tree growth and carbon storage in woody tissue in the warmed plot. The increased carbon storage in the trees compensated for more than half of the carbon lost from the soils due to accelerated decay of soil organic matter and so reduced the magnitude of the positive feedback to the climate system due to soil warming. We hypothesize that the increase in nitrification we observed will eventually "open" the nitrogen cycle and make gaseous and solution losses more likely. To date, however, we have measured no major losses of nitrous oxide or solution losses of nitrate in response to soil warming. Trees with the capacity to use nitrate may have a competitive advantage in a warmer world. Nitrate-using plants have an inducible enzyme that transforms nitrate to ammonium, a key building block for producing essential amino acids and proteins. Studies by our research group and by others have shown that red maples (Acer rubrum), when grown with high levels of nitrate, have a greater ability to produce this enzyme than many other species common to the region's forests. We have also observed that red maple seedlings and saplings show a higher growth response to soil warming than juvenile plants of other species. Our working hypothesis is that some of this response is linked to the capacity of red maple to use the nitrate produced in the warmed soils. In the long term, warming could lead to red maples becoming a more dominant tree in the forests of southern New England.

  15. Predicting changes in alluvial channel patterns in North-European Russia under conditions of global warming

    NASA Astrophysics Data System (ADS)

    Anisimov, Oleg; Vandenberghe, Jef; Lobanov, Vladimir; Kondratiev, Alexander

    2008-06-01

    Global climate change may have a noticeable impact on the northern environment, leading to changes in permafrost, vegetation and fluvial morphology. In this paper we compare the results from three geomorphological models and study the potential effects of changing climatic factors on the river channel types in North-European Russia. Two of the selected models by Romashin [Romashin, V.V., 1968. Variations of the river channel types under governing factors, Annals of the Hydrological Institute, vol. 155. Hydrometeoizdat, Leningrad, pp. 56-63.] and Leopold and Wolman [Leopold, L.B., Wolman, M.G., 1957. River channel pattern: braided, meandering and straight, Physiographic and hydraulic studies of rivers. USA Geological Survey Professional Paper 252, pp. 85-98.] are conventional QS-type models, which predict the existence of either multi-thread or single-tread channel types using data on discharge and channel slope. The more advanced model by Van den Berg [Van den Berg, J.H., 1995. Prediction of alluvial channel pattern of perennial rivers. Geomorphology 12, 259-270.] takes into account the size of the sediment material. We used data from 16 runoff gauges to validate the models and predict the channel types at selected locations under modern and predicted for the future climatic conditions. Two of the three models successfully replicated the currently existing channel types in all but one of the studied sites. Predictive calculations under the hypothetical scenarios of 10%, 15%, 20% and 35% runoff increase gave different results. Van den Berg's model predicted potential transformation of the channel types, from single- to multi-thread, at 4 of 16 selected locations in the next few decades, and at 5 locations by the middle of the 21st century. Each of the QS-type models predicted such transformation at one site only. Results of the study indicate that climatic warming in combination with other environmental changes may lead to transformation of the river channel types at selected locations in north-western Russia. Further efforts are needed to improve the performance of the fluvial geomorphological models and their ability to predict such changes.

  16. Heat-related mortality in a warming climate: projections for 12 U.S. cities.

    PubMed

    Petkova, Elisaveta P; Bader, Daniel A; Anderson, G Brooke; Horton, Radley M; Knowlton, Kim; Kinney, Patrick L

    2014-11-01

    Heat is among the deadliest weather-related phenomena in the United States, and the number of heat-related deaths may increase under a changing climate, particularly in urban areas. Regional adaptation planning is unfortunately often limited by the lack of quantitative information on potential future health responses. This study presents an assessment of the future impacts of climate change on heat-related mortality in 12 cities using 16 global climate models, driven by two scenarios of greenhouse gas emissions. Although the magnitude of the projected heat effects was found to differ across time, cities, climate models and greenhouse pollution emissions scenarios, climate change was projected to result in increases in heat-related fatalities over time throughout the 21st century in all of the 12 cities included in this study. The increase was more substantial under the high emission pathway, highlighting the potential benefits to public health of reducing greenhouse gas emissions. Nearly 200,000 heat-related deaths are projected to occur in the 12 cities by the end of the century due to climate warming, over 22,000 of which could be avoided if we follow a low GHG emission pathway. The presented estimates can be of value to local decision makers and stakeholders interested in developing strategies to reduce these impacts and building climate change resilience. PMID:25365060

  17. Heat-Related Mortality in a Warming Climate: Projections for 12 U.S. Cities

    NASA Technical Reports Server (NTRS)

    Petkova, Elisaveta P.; Bader, Daniel A.; Anderson, G. Brooke; Horton, Radley M.; Knowlton, Kim; Kinney, Patrick L.

    2014-01-01

    Heat is among the deadliest weather-related phenomena in the United States, and the number of heat-related deaths may increase under a changing climate, particularly in urban areas. Regional adaptation planning is unfortunately often limited by the lack of quantitative information on potential future health responses. This study presents an assessment of the future impacts of climate change on heat-related mortality in 12 cities using 16 global climate models, driven by two scenarios of greenhouse gas emissions. Although the magnitude of the projected heat effects was found to differ across time, cities, climate models and greenhouse pollution emissions scenarios, climate change was projected to result in increases in heat-related fatalities over time throughout the 21st century in all of the 12 cities included in this study. The increase was more substantial under the high emission pathway, highlighting the potential benefits to public health of reducing greenhouse gas emissions. Nearly 200,000 heat-related deaths are projected to occur in the 12 cities by the end of the century due to climate warming, over 22,000 of which could be avoided if we follow a low GHG emission pathway. The presented estimates can be of value to local decision makers and stakeholders interested in developing strategies to reduce these impacts and building climate change resilience.

  18. Estimating thermal regimes of bull trout and assessing the potential effects of climate warming on critical habitats

    USGS Publications Warehouse

    Jones, Leslie A.; Muhlfeld, Clint C.; Marshall, Lucy A.; McGlynn, Brian L.; Kershner, Jeffrey L.

    2013-01-01

    Understanding the vulnerability of aquatic species and habitats under climate change is critical for conservation and management of freshwater systems. Climate warming is predicted to increase water temperatures in freshwater ecosystems worldwide, yet few studies have developed spatially explicit modelling tools for understanding the potential impacts. We parameterized a nonspatial model, a spatial flow-routed model, and a spatial hierarchical model to predict August stream temperatures (22-m resolution) throughout the Flathead River Basin, USA and Canada. Model comparisons showed that the spatial models performed significantly better than the nonspatial model, explaining the spatial autocorrelation found between sites. The spatial hierarchical model explained 82% of the variation in summer mean (August) stream temperatures and was used to estimate thermal regimes for threatened bull trout (Salvelinus confluentus) habitats, one of the most thermally sensitive coldwater species in western North America. The model estimated summer thermal regimes of spawning and rearing habitats at <13 C° and foraging, migrating, and overwintering habitats at <14 C°. To illustrate the useful application of such a model, we simulated climate warming scenarios to quantify potential loss of critical habitats under forecasted climatic conditions. As air and water temperatures continue to increase, our model simulations show that lower portions of the Flathead River Basin drainage (foraging, migrating, and overwintering habitat) may become thermally unsuitable and headwater streams (spawning and rearing) may become isolated because of increasing thermal fragmentation during summer. Model results can be used to focus conservation and management efforts on populations of concern, by identifying critical habitats and assessing thermal changes at a local scale.

  19. Responses of the leading mode of coldwave intensity in China to a warming climate

    NASA Astrophysics Data System (ADS)

    Ma, Tingting; Jiang, Zhihong; Wu, Zhiwei

    2013-10-01

    Regional extreme cold events have changed notably with recent global warming. Understanding how these cold extremes change in China is an urgent issue. This study examines the responses of the dominant mode of China coldwave intensity (CWI) to global warming by comparing observations with simulations from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The leading modes of the CWI derived from empirical orthogonal function (EOF) analysis have different features in different epochs. During the cold period (1957-1979), the leading mode is characterized by centers of extreme values of CWI in northern China; while during the warm period (1980-2009), the leading mode features two maximum loading centers over northern and southern China. The southward extension of the extreme value center is associated with an increase in the intensity of coldwave variations in southern China relative to previous decades. A multi-model ensemble of seven state-of-the-art climate models shows an extension of the maximum loading of the CWI leading mode into southern China by the end of the 21st century (2080-2099) under the A1B global warming scenario (atmospheric CO2 concentration of 720 ppm). These results indicate that the primary response of the leading mode of CWI to global warming might be a southward extension of the extreme value center. This response may be associated with the southward shift of the storm track observed during recent decades. A significant change in the baroclinic growth rates around 40°N is accompanied by a consistent change in synoptic eddies in the troposphere, which may indicate a shift in the preferred latitude for the growth of eddies. As a result, the storm track tends to move southward, suggesting that southern China may experience increased storminess due to increased baroclinic instability in the troposphere.

  20. Shallowness of tropical low clouds as a predictor of climate models' response to warming

    NASA Astrophysics Data System (ADS)

    Brient, Florent; Schneider, Tapio; Tan, Zhihong; Bony, Sandrine; Qu, Xin; Hall, Alex

    2015-10-01

    How tropical low clouds change with climate remains the dominant source of uncertainty in global warming projections. An analysis of an ensemble of CMIP5 climate models reveals that a significant part of the spread in the models' climate sensitivity can be accounted by differences in the climatological shallowness of tropical low clouds in weak-subsidence regimes: models with shallower low clouds in weak-subsidence regimes tend to have a higher climate sensitivity than models with deeper low clouds. The dynamical mechanisms responsible for the model differences are analyzed. Competing effects of parameterized boundary-layer turbulence and shallow convection are found to be essential. Boundary-layer turbulence and shallow convection are typically represented by distinct parameterization schemes in current models—parameterization schemes that often produce opposing effects on low clouds. Convective drying of the boundary layer tends to deepen low clouds and reduce the cloud fraction at the lowest levels; turbulent moistening tends to make low clouds more shallow but affects the low-cloud fraction less. The relative importance different models assign to these opposing mechanisms contributes to the spread of the climatological shallowness of low clouds and thus to the spread of low-cloud changes under global warming.

  1. Thermal Plasticity of Photosynthesis: the Role of Acclimation in Forest Responses to a Warming Climate

    SciTech Connect

    Gunderson, Carla A; O'Hara, Keiran H; Campion, Christina M; Walker, Ashley V; Edwards, Nelson T

    2010-01-01

    The increasing air temperatures central to climate change predictions have the potential to alter forest ecosystem function and structure by exceeding temperatures optimal for carbon gain. Such changes are projected to threaten survival of sensitive species, leading to local extinctions, range migrations, and altered forest composition. This study investigated photosynthetic sensitivity to temperature and the potential for acclimation in relation to the climatic provenance of five species of deciduous trees, Liquidambar styraciflua, Quercus rubra, Quercus falcata, Betula alleghaniensis, and Populus grandidentata. Open-top chambers supplied three levels of warming (+0, +2, and +4 C above ambient) over 3 years, tracking natural temperature variability. Optimal temperature for CO2 assimilation was strongly correlated with daytime temperature in all treatments, but assimilation rates at those optima were comparable. Adjustment of thermal optima was confirmed in all species, whether temperatures varied with season or treatment, and regardless of climate in the species' range or provenance of the plant material. Temperature optima from 17 to 34 were observed. Across species, acclimation potentials varied from 0.55 C to 1.07 C per degree change in daytime temperature. Responses to the temperature manipulation were not different from the seasonal acclimation observed in mature indigenous trees, suggesting that photosynthetic responses should not be modeled using static temperature functions, but should incorporate an adjustment to account for acclimation. The high degree of homeostasis observed indicates that direct impacts of climatic warming on forest productivity, species survival, and range limits may be less than predicted by existing models.

  2. The Effect of Urban Heat Island on Climate Warming in the Yangtze River Delta Urban Agglomeration in China

    PubMed Central

    Huang, Qunfang; Lu, Yuqi

    2015-01-01

    The Yangtze River Delta (YRD) has experienced rapid urbanization and dramatic economic development since 1978 and the Yangtze River Delta urban agglomeration (YRDUA) has been one of the three largest urban agglomerations in China. We present evidence of a significant urban heat island (UHI) effect on climate warming based on an analysis of the impacts of the urbanization rate, urban population, and land use changes on the warming rate of the daily average, minimal (nighttime) and maximal (daytime) air temperature in the YRDUA using 41 meteorological stations observation data. The effect of the UHI on climate warming shows a large spatial variability. The average warming rates of average air temperature of huge cities, megalopolises, large cities, medium-sized cities, and small cities are 0.483, 0.314 ± 0.030, 0.282 ± 0.042, 0.225 ± 0.044 and 0.179 ± 0.046 °C/decade during the period of 1957–2013, respectively. The average warming rates of huge cities and megalopolises are significantly higher than those of medium-sized cities and small cities, indicating that the UHI has a significant effect on climate warming (t-test, p < 0.05). Significantly positive correlations are found between the urbanization rate, population, built-up area and warming rate of average air temperature (p < 0.001). The average warming rate of average air temperature attributable to urbanization is 0.124 ± 0.074 °C/decade in the YRDUA. Urbanization has a measurable effect on the observed climate warming in the YRD aggravating the global climate warming. PMID:26225986

  3. Warm climates of the past—a lesson for the future?

    PubMed Central

    Lunt, D. J.; Elderfield, H.; Pancost, R.; Ridgwell, A.; Foster, G. L.; Haywood, A.; Kiehl, J.; Sagoo, N.; Shields, C.; Stone, E. J.; Valdes, P.

    2013-01-01

    This Discussion Meeting Issue of the Philosophical Transactions A had its genesis in a Discussion Meeting of the Royal Society which took place on 10–11 October 2011. The Discussion Meeting, entitled ‘Warm climates of the past: a lesson for the future?’, brought together 16 eminent international speakers from the field of palaeoclimate, and was attended by over 280 scientists and members of the public. Many of the speakers have contributed to the papers compiled in this Discussion Meeting Issue. The papers summarize the talks at the meeting, and present further or related work. This Discussion Meeting Issue asks to what extent information gleaned from the study of past climates can aid our understanding of future climate change. Climate change is currently an issue at the forefront of environmental science, and also has important sociological and political implications. Most future predictions are carried out by complex numerical models; however, these models cannot be rigorously tested for scenarios outside of the modern, without making use of past climate data. Furthermore, past climate data can inform our understanding of how the Earth system operates, and can provide important contextual information related to environmental change. All past time periods can be useful in this context; here, we focus on past climates that were warmer than the modern climate, as these are likely to be the most similar to the future. This introductory paper is not meant as a comprehensive overview of all work in this field. Instead, it gives an introduction to the important issues therein, using the papers in this Discussion Meeting Issue, and other works from all the Discussion Meeting speakers, as exemplars of the various ways in which past climates can inform projections of future climate. Furthermore, we present new work that uses a palaeo constraint to quantitatively inform projections of future equilibrium ice sheet change. PMID:24043873

  4. Change in abundance of pacific brant wintering in alaska: evidence of a climate warming effect?

    USGS Publications Warehouse

    Ward, D.H.; Dau, C.P.; Lee, T.; Sedinger, J.S.; Anderson, B.A.; Hines, J.E.

    2009-01-01

    Winter distribution of Pacific Flyway brant (Branta bernicla nigricans) has shifted northward from lowtemperate areas to sub-Arctic areas over the last 42 years. We assessed the winter abundance and distribution of brant in Alaska to evaluate whether climate warming may be contributing to positive trends in the most northern of the wintering populations. Mean surface air temperatures during winter at the end of the Alaska Peninsula increased about 1??C between 1963 and 2004, resulting in a 23% reduction in freezing degree days and a 34% decline in the number of days when ice cover prevents birds from accessing food resources. Trends in the wintering population fluctuated with states of the Pacific Decadal Oscillation, increasing during positive (warm) phases and decreasing during negative (cold) phases, and this correlation provides support for the hypothesis that growth in the wintering population of brant in Alaska is linked to climate warming. The size of the wintering population was negatively correlated with the number of days of strong northwesterly winds in November, which suggests that the occurrence of tailwinds favorable for migration before the onset of winter was a key factor in whether brant migrated from Alaska or remained there during winter. Winter distribution of brant on the Alaska Peninsula was highly variable and influenced by ice cover, particularly at the heavily used Izembek Lagoon. Observations of previously marked brant indicated that the Alaska wintering population was composed primarily of birds originating from Arctic breeding colonies that appear to be growing. Numbers of brant in Alaska during winter will likely increase as temperatures rise and ice cover decreases at high latitudes in response to climate warming. ?? The Arctic Institute of North America.

  5. Changing forest water yields in response to climate warming: results from long-term experimental watershed sites across North America

    PubMed Central

    Creed, Irena F; Spargo, Adam T; Jones, Julia A; Buttle, Jim M; Adams, Mary B; Beall, Fred D; Booth, Eric G; Campbell, John L; Clow, Dave; Elder, Kelly; Green, Mark B; Grimm, Nancy B; Miniat, Chelcy; Ramlal, Patricia; Saha, Amartya; Sebestyen, Stephen; Spittlehouse, Dave; Sterling, Shannon; Williams, Mark W; Winkler, Rita; Yao, Huaxia

    2014-01-01

    Climate warming is projected to affect forest water yields but the effects are expected to vary. We investigated how forest type and age affect water yield resilience to climate warming. To answer this question, we examined the variability in historical water yields at long-term experimental catchments across Canada and the United States over 5-year cool and warm periods. Using the theoretical framework of the Budyko curve, we calculated the effects of climate warming on the annual partitioning of precipitation (P) into evapotranspiration (ET) and water yield. Deviation (d) was defined as a catchment's change in actual ET divided by P [AET/P; evaporative index (EI)] coincident with a shift from a cool to a warm period – a positive d indicates an upward shift in EI and smaller than expected water yields, and a negative d indicates a downward shift in EI and larger than expected water yields. Elasticity was defined as the ratio of interannual variation in potential ET divided by P (PET/P; dryness index) to interannual variation in the EI – high elasticity indicates low d despite large range in drying index (i.e., resilient water yields), low elasticity indicates high d despite small range in drying index (i.e., nonresilient water yields). Although the data needed to fully evaluate ecosystems based on these metrics are limited, we were able to identify some characteristics of response among forest types. Alpine sites showed the greatest sensitivity to climate warming with any warming leading to increased water yields. Conifer forests included catchments with lowest elasticity and stable to larger water yields. Deciduous forests included catchments with intermediate elasticity and stable to smaller water yields. Mixed coniferous/deciduous forests included catchments with highest elasticity and stable water yields. Forest type appeared to influence the resilience of catchment water yields to climate warming, with conifer and deciduous catchments more susceptible to climate warming than the more diverse mixed forest catchments. PMID:24757012

  6. Changing hydrological conditions in the Po basin under global warming

    NASA Astrophysics Data System (ADS)

    Coppola, Erika; Verdecchia, Marco; Giorgi, Filippo; Colaiuda, Valentina; Tomassetti, Barbara; Lombardi, Annalina

    2014-05-01

    The Po River is a crucial resource for the Italian economy since 40% of the gross domestic product comes from this area. To quantify the impact of climate change on this water resource is then crucial for planning the water use and distribution in the near future. In this paper a mini ensemble of 8 hydrological simulations are completed from 1960 to 2050 under the A1B scenario, by using as input the output of two regional climate models (REMO and RegCM) at two different resolutions (25 km -10km and 25km-3km). The river discharge at the closing point of the basin shows a change in the spring pick of annual cycle and one month shift is evident from May to April. This shift is entirely due to the changing in the snowmelt timing because that drives most of the discharge in this period. The others two important changes are the increase of discharge in the wintertime and the decrease in fall from September to November. The uncertainty associated with the winter change is bigger compared to that in fall. The spring shift and the fall decrease of discharge imply an extension of the hydrological dry seasons and thus increasing water stress over the basin. The spatial distribution of the discharge changes are in agreement with what is observed at the closing point and the uncertainty associated with these changes are proportional to the amplitude of the signal. By looking at the changes in the anomaly distribution of discharge it seems evident that either the increase or decrease of seasonal discharge is tied to the changes in the tails of the distribution, namely to the increase or decrease of the extreme events.

  7. Changing hydrological conditions in the Po basin under global warming.

    PubMed

    Coppola, Erika; Verdecchia, Marco; Giorgi, Filippo; Colaiuda, Valentina; Tomassetti, Barbara; Lombardi, Annalina

    2014-09-15

    The Po River is a crucial resource for the Italian economy, since 40% of the gross domestic product comes from this area. It is thus crucial to quantify the impact of climate change on this water resource in order to plan for future water use. In this paper a mini ensemble of 8 hydrological simulations is completed from 1960 to 2050 under the A1B emission scenario, by using the output of two regional climate models as input (REMO and RegCM) at two different resolutions (25 km-10 km and 25 km-3 km). The river discharge at the outlet point of the basin shows a change in the spring peak of the annual cycle, with a one month shift from May to April. This shift is entirely due to the change in snowmelt timing which drives most of the discharge during this period. Two other important changes are an increase of discharge in the wintertime and a decrease in the fall from September to November. The uncertainty associated with the winter change is larger compared to that in the fall. The spring shift and the fall decrease of discharge imply an extension of the hydrological dry season and thus an increase in water stress over the basin. The spatial distributions of the discharge changes are in agreement with what is observed at the outlet point and the uncertainty associated with these changes is proportional to the amplitude of the signal. The analysis of the changes in the anomaly distribution of discharge shows that both the increases and decreases in seasonal discharge are tied to the changes in the tails of the distribution, i.e. to the increase or decrease of extreme events. PMID:24656403

  8. Warm-dry collocation of recent drought in southwestern China tied to moisture transport and climate warming

    NASA Astrophysics Data System (ADS)

    Dai, Xin-Gang; Liu, Ye; Wang, Ping

    2015-04-01

    This study aims to investigate the recent drought in southwestern China and its association with environmental changes in moisture transport (MT) and atmospheric circulation. Climatic Research Unit grid data, in situ observations in China, and ERA-interim reanalysis are used to study the characteristics of the drought and the associated mechanism. Recent precipitation trends show a pattern of “Northern wetting and Southern drying”, similar to the anti-phase of the climate pattern prevailing during 1980-2000 in mainland China; southwestern China incurred a severe drought during 2009-2013. Wavelet analysis reveals that the drought coincides with a warm-dry phase of temperature and precipitation on a period of about 20 years and beyond 100 years, where contributions account for 43% and 57% of the deficiency of the precipitation, averaged for 2003-2012, respectively. A further investigation reveals that the drought results chiefly from the decline of the southwestern monsoon MT toward southwestern China, in addition to mid-latitude circulation changes, which leads to more blockings near the Ural Mountains and the Sea of Okhotsk in the rainy season and negative anomalies around Lake Baikal and northeast China in the dry season. These anomalies are likely to be correlated with global sea surface temperature changes and need to be studied further. Project supported by the National Basic Research and Development Program of China (Grant No. 2013CB430201), the National Natural Science Foundation of China (Grant Nos. 41075058 and 41475075), and the China Meteorological Administration Special Public Welfare Research Fund (Grant No. GYHY201106016).

  9. Elevational differences in developmental plasticity determine phenological responses of grasshoppers to recent climate warming.

    PubMed

    Buckley, Lauren B; Nufio, César R; Kirk, Evan M; Kingsolver, Joel G

    2015-06-22

    Annual species may increase reproduction by increasing adult body size through extended development, but risk being unable to complete development in seasonally limited environments. Synthetic reviews indicate that most, but not all, species have responded to recent climate warming by advancing the seasonal timing of adult emergence or reproduction. Here, we show that 50 years of climate change have delayed development in high-elevation, season-limited grasshopper populations, but advanced development in populations at lower elevations. Developmental delays are most pronounced for early-season species, which might benefit most from delaying development when released from seasonal time constraints. Rearing experiments confirm that population, elevation and temperature interact to determine development time. Population differences in developmental plasticity may account for variability in phenological shifts among adults. An integrated consideration of the full life cycle that considers local adaptation and plasticity may be essential for understanding and predicting responses to climate change. PMID:26041342

  10. Persistent cold air outbreaks over North America in a warming climate

    NASA Astrophysics Data System (ADS)

    Gao, Yang; Leung, L. Ruby; Lu, Jian; Masato, Giacomo

    2015-04-01

    This study examines future changes of cold air outbreaks (CAOs) using a multi-model ensemble of global climate simulations from the Coupled Model Intercomparison Project Phase 5 and high resolution regional climate simulations. Overall, climate models agree on a dip in CAO duration across North America, but the percentage change is consistently smaller from western Canada to the upper mid-western US with historically more frequent CAO. By decomposing the changes of the probability density function of daily surface temperature into changes due to mean warming and changes in standard deviation (std) and skewness/higher order moments, the contributions of each factor to CAO changes are quantified. Results show that CAO changes can be explained largely by the mean warming, but the decrease in temperature std contributes to about 20% reduction of CAO from Alaska to northeastern US and eastern Canada possibly due to the Arctic amplification and weakening of storm track. A thermodynamical modulation of the skewness called the ‘0 °C mode’ effect is found to operate prominently along the 0 °C isotherm hemispherically and reduce CAO in western and northeastern US with winter snow cover by up to 10%. This effect also produces a manifold increase in CAO events over the Arctic sea ice. An increased frequency in atmospheric blocking also contributes to increases in CAO duration over Alaska and the Arctic region. Regional simulations revealed more contributions of existing snowpack to CAO in the near future over the Rocky Mountain, southwestern US, and Great Lakes areas through surface albedo effects. 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 US, the top five most extreme CAO events may still occur, and wind chill will continue to have societal impacts in that region.

  11. Climate-induced warming imposes a threat to north European spring ecosystems.

    PubMed

    Jyväsjärvi, Jussi; Marttila, Hannu; Rossi, Pekka M; Ala-Aho, Pertti; Olofsson, Bo; Nisell, Jakob; Backman, Birgitta; Ilmonen, Jari; Virtanen, Risto; Paasivirta, Lauri; Britschgi, Ritva; Kløve, Bjørn; Muotka, Timo

    2015-12-01

    Interest in climate change effects on groundwater has increased dramatically during the last decade. The mechanisms of climate-related groundwater depletion have been thoroughly reviewed, but the influence of global warming on groundwater-dependent ecosystems (GDEs) remains poorly known. Here we report long-term water temperature trends in 66 northern European cold-water springs. A vast majority of the springs (82%) exhibited a significant increase in water temperature during 1968-2012. Mean spring water temperatures were closely related to regional air temperature and global radiative forcing of the corresponding year. Based on three alternative climate scenarios representing low (RCP2.6), intermediate (RCP6) and high-emission scenarios (RCP8.5), we estimate that increase in mean spring water temperature in the region is likely to range from 0.67 °C (RCP2.6) to 5.94 °C (RCP8.5) by 2086. According to the worst-case scenario, water temperature of these originally cold-water ecosystems (regional mean in the late 1970s: 4.7 °C) may exceed 12 °C by the end of this century. We used bryophyte and macroinvertebrate species data from Finnish springs and spring-fed streams to assess ecological impacts of the predicted warming. An increase in spring water temperature by several degrees will likely have substantial biodiversity impacts, causing regional extinction of native, cold-stenothermal spring specialists, whereas species diversity of headwater generalists is likely to increase. Even a slight (by 1 °C) increase in water temperature may eliminate endemic spring species, thus altering bryophyte and macroinvertebrate assemblages of spring-fed streams. Climate change-induced warming of northern regions may thus alter species composition of the spring biota and cause regional homogenization of biodiversity in headwater ecosystems. PMID:26300476

  12. Sensitivity of spring phenology to warming across temporal and spatial climate gradients in two independent databases

    USGS Publications Warehouse

    Cook, Benjamin I.; Wolkovich, Elizabeth M.; Davies, T. Jonathan; Ault, Toby R.; Betancourt, Julio L.; Allen, Jenica M.; Bolmgren, Kjell; Cleland, Elsa E.; Crimmins, Theresa M.; Kraft, Nathan J.B.; Lancaster, Lesley T.; Mazer, Susan J.; McCabe, Gregory J.; McGill, Brian J.; Parmesan, Camille; Pau, Stephanie; Regetz, James; Salamin, Nicolas; Schwartz, Mark D.; Travers, Steven E.

    2012-01-01

    Disparate ecological datasets are often organized into databases post hoc and then analyzed and interpreted in ways that may diverge from the purposes of the original data collections. Few studies, however, have attempted to quantify how biases inherent in these data (for example, species richness, replication, climate) affect their suitability for addressing broad scientific questions, especially in under-represented systems (for example, deserts, tropical forests) and wild communities. Here, we quantitatively compare the sensitivity of species first flowering and leafing dates to spring warmth in two phenological databases from the Northern Hemisphere. One—PEP725—has high replication within and across sites, but has low species diversity and spans a limited climate gradient. The other—NECTAR—includes many more species and a wider range of climates, but has fewer sites and low replication of species across sites. PEP725, despite low species diversity and relatively low seasonality, accurately captures the magnitude and seasonality of warming responses at climatically similar NECTAR sites, with most species showing earlier phenological events in response to warming. In NECTAR, the prevalence of temperature responders significantly declines with increasing mean annual temperature, a pattern that cannot be detected across the limited climate gradient spanned by the PEP725 flowering and leafing data. Our results showcase broad areas of agreement between the two databases, despite significant differences in species richness and geographic coverage, while also noting areas where including data across broader climate gradients may provide added value. Such comparisons help to identify gaps in our observations and knowledge base that can be addressed by ongoing monitoring and research efforts. Resolving these issues will be critical for improving predictions in understudied and under-sampled systems outside of the temperature seasonal mid-latitudes.

  13. The intrinsic growth rate as a predictor of population viability under climate warming.

    PubMed

    Amarasekare, Priyanga; Coutinho, Renato M

    2013-11-01

    1. Lately, there has been interest in using the intrinsic growth rate (rm) to predict the effects of climate warming on ectotherm population viability. However, because rm is calculated using the Euler-Lotka equation, its reliability in predicting population persistence depends on whether ectotherm populations can achieve a stable age/stage distribution in thermally variable environments. Here, we investigate this issue using a mathematical framework that incorporates mechanistic descriptions of temperature effects on vital rates into a stage-structured population model that realistically captures the temperature-induced variability in developmental delays that characterize ectotherm life cycles. 2. We find that populations experiencing seasonal temperature variation converge to a stage distribution whose intra-annual pattern remains invariant across years. As a result, the mean annual per capita growth rate also remains constant between years. The key insight is the mechanism that allows populations converge to a stationary stage distribution. Temperature effects on the biochemical processes (e.g. enzyme kinetics, hormonal regulation) that underlie life-history traits (reproduction, development and mortality) exhibit well-defined thermodynamical properties (e.g. changes in entropy and enthalpy) that lead to predictable outcomes (e.g. reduction in reaction rates or hormonal action at temperature extremes). As a result, life-history traits exhibit a systematic and predictable response to seasonal temperature variation. This in turn leads to temporally predictable temperature responses of the stage distribution and the per capita growth rate. 3. When climate warming causes an increase in the mean annual temperature and/or the amplitude of seasonal fluctuations, the population model predicts the mean annual per capita growth rate to decline to zero within 100 years when warming is slow relative to the developmental period of the organism (0.03-0.05°C per year) and to become negative, causing population extinction, well before 100 years when warming is fast (e.g. 0.1°C per year). The Euler-Lotka equation predicts a slower decrease in rm when warming is slow and a longer persistence time when warming is fast, with the deviation between the two metrics increasing with increasing developmental period. These results suggest that predictions of ectotherm population viability based on rm may be valid only for species with short developmental delays, and even then, only over short time-scales and under slow warming regimes. PMID:23926903

  14. Climatic warming and basal melting of large ice sheets: possible implications for East Antarctica

    SciTech Connect

    Saari, M.R.; Yuen, D.A.; Schubert, G.

    1987-01-01

    Climatic warming is shown to be capable of inducing shear heating instability and basal melting in a model ice sheet that is creeping slowly downslope. Growth times of the instability are calculated from a nonlinear analysis of temperature and flow in the model ice sheet whose surface undergoes a prescribed increase of temperature. The source of instability lies in the decrease of maximum ice thickness for steady downslope creep with increasing surface temperature. A surface temperature increase of 5 to 10 k can cause instability on a 10/sup 4/ year time scale for realistic ice rheology. The instability occurs suddenly after a prolonged period of dormancy. The instability might be relevant to the East Antarctic ice sheet. Warming associated with the Holocene interglacial epoch that heralded the end of the last ice age may have set the East Antarctic ice sheet on a course toward wide-spread instability some 10/sup 4/ years later. The present CO/sub 2/-induced climate warming is also a potential trigger for instability and basal melting of the East Antarctic ice sheet.

  15. Aerosol microphysical effects on warm cloud in Eastern China: impacts of meteorological conditions

    NASA Astrophysics Data System (ADS)

    Guo, J.; Wang, F.; Li, Z.

    2013-12-01

    Atmospheric aerosol particles can alter the droplet size and number concentration of clouds, thereby changing the Earth's climate system. The aerosol indirect effect has been proved climatically significant after decades of research, albeit uncertain. This is partially due to the frustrating difficulty in decoupling the aerosol effect from meteorology influences on cloud properties. This study attempts to probe into the aerosol indirect effect on the warm clouds of summertime the Yangtze River Delta (YRD) of eastern China and East China Sea (ECS), respectively. It is based on simultaneously observed aerosol and cloud properties from MODIS/Aqua Level 3 datasets, along with meteorological properties from NCEP Final Analyses Operational Global Analysis datasets. Statistic analysis is employed to analyze the aerosol cloud interaction, constrained by multiple meteorological conditions, such as cloud top pressure (CTP), relative humidity (RH), pressure vertical velocity (PVV) and lower tropospheric stability (LTS), expected to minimize meteorological impact. The reduction of cloud droplet radius (CDR) with increasing aerosol optical depth (AOD) is revealed over ECS. In contrast, anti-Twomey effect is detected over YRD. The aerosol effects on cloud fraction (CF) are further investigated, taking CTP and RH into account. CF is found to increase more sharply over YRD than over ECS in response to aerosol enhancement, regardless of RH conditions. In addition, the horizontal extension of cloud is prone to be driven by aerosol rather than RH in the summertime over YRD. Meanwhile, CTP effect on AOD-CF is eliminated, indicating CTP make little contribution to the observed AOD-CF relationship. Also, CDR variation in response to AOD, constrained by LTS and PVV (750hPa) is analyzed. In general, aerosol tends to observe the law of Twomey's effect except for the unstable condition over land. Regarding dynamic effect, the rising atmospheric environment is subject to larger CDR than the subsidence environment under the same aerosol abundance, irrespective of over land and ocean, which can be attributed to the rising motion favoring the growth of cloud droplet. Overall, the observed cloud response to aerosol reflects the combined effects of dynamic, thermodynamic, and microphysical processes in cloud systems.

  16. The influence of convection parameterisations under alternate climate conditions

    NASA Astrophysics Data System (ADS)

    Rybka, Harald; Tost, Holger

    2013-04-01

    In the last decades several convection parameterisations have been developed to consider the impact of small-scale unresolved processes in Earth System Models associated with convective clouds. Global model simulations, which have been performed under current climate conditions with different convection schemes, significantly differ among each other in the simulated precipitation patterns due to the parameterisation assumptions and formulations, e.g. the simplified treatment of the cloud microphysics. Additionally, the simulated transport of short-lived trace gases strongly depends on the chosen convection parameterisation due to the differences in the vertical redistribution of mass. Furthermore, other meteorological parameters like the temperature or the specific humidity show substantial differences in convectively active regions. This study presents uncertainties of climate change scenarios caused by different convection parameterisations. For this analysis two experiments (reference simulation with a CO2 concentration of 348 ppm; 2xCO2-simulation with a CO2 concentration of 696 ppm) are calculated with the ECHAM/MESSy atmospheric chemistry (EMAC) model applying four different convection schemes (Tiedtke, ECMWF, Emanuel and Zhang-McFarlane - Hack) and two resolutions (T42 and T63), respectively. The results indicate that the equilibrium climate sensitivity is independent of the chosen convection parameterisation. However, the regional temperature increase, induced by a doubling of the carbon dioxide concentration, demonstrates differences of up to a few Kelvin at the surface as well as in the UTLS for the ITCZ region depending on the selected convection parameterisation. The interaction between cloud and convection parameterisations results in a large disagreement of precipitation patterns. Although every 2xCO2 -experiment simulates an increase in global mean precipitation rates, the change of regional precipitation patterns differ widely. Finally, analysing the cloud radiative forcing a huge spread of the cloud-induced radiative flux change is found in the warm pool region due to a change of the convection parameterisation.

  17. Enhancing Primary School Students' Knowledge about Global Warming and Environmental Attitude Using Climate Change Activities

    ERIC Educational Resources Information Center

    Karpudewan, Mageswary; Roth, Wolff-Michael; Bin Abdullah, Mohd Nor Syahrir

    2015-01-01

    Climate change generally and global warming specifically have become a common feature of the daily news. Due to widespread recognition of the adverse consequences of climate change on human lives, concerted societal effort has been taken to address it (e.g. by means of the science curriculum). This study was designed to test the effect that…

  18. CLIMATE CHANGE. Possible artifacts of data biases in the recent global surface warming hiatus.

    PubMed

    Karl, Thomas R; Arguez, Anthony; Huang, Boyin; Lawrimore, Jay H; McMahon, James R; Menne, Matthew J; Peterson, Thomas C; Vose, Russell S; Zhang, Huai-Min

    2015-06-26

    Much study has been devoted to the possible causes of an apparent decrease in the upward trend of global surface temperatures since 1998, a phenomenon that has been dubbed the global warming "hiatus." Here, we present an updated global surface temperature analysis that reveals that global trends are higher than those reported by the Intergovernmental Panel on Climate Change, especially in recent decades, and that the central estimate for the rate of warming during the first 15 years of the 21st century is at least as great as the last half of the 20th century. These results do not support the notion of a "slowdown" in the increase of global surface temperature. PMID:26044301

  19. Mass extinctions, atmospheric sulphur and climatic warming at the K/T boundary

    NASA Technical Reports Server (NTRS)

    Rampino, Michael R.; Volk, Tyler

    1988-01-01

    The possible climatic effects of a drastic decrease in cloud condensation nuclei (CCN) associated with a severe reduction in the global marine phytoplankton abundance are investigated. Calculations suggest that a reduction in CCN of more than 80 percent and the resulting decrease in marine cloud albedo could have produced a rapid global warming of 6 C or more. Oxygen isotope analyses of marine sediments from many parts of the world have been interpreted as indicating a marked warming coincident with the demise of calcareous nannoplankton at the K/T boundary. Decreased marine cloud albedo and resulting high sea surface temperatures could have been a factor in the maintenance of low productivity in the 'Strangelove Ocean' period following the K/T extinctions.

  20. Climate change. Projected increase in lightning strikes in the United States due to global warming.

    PubMed

    Romps, David M; Seeley, Jacob T; Vollaro, David; Molinari, John

    2014-11-14

    Lightning plays an important role in atmospheric chemistry and in the initiation of wildfires, but the impact of global warming on lightning rates is poorly constrained. Here we propose that the lightning flash rate is proportional to the convective available potential energy (CAPE) times the precipitation rate. Using observations, the product of CAPE and precipitation explains 77% of the variance in the time series of total cloud-to-ground lightning flashes over the contiguous United States (CONUS). Storms convert CAPE times precipitated water mass to discharged lightning energy with an efficiency of 1%. When this proxy is applied to 11 climate models, CONUS lightning strikes are predicted to increase 12 ± 5% per degree Celsius of global warming and about 50% over this century. PMID:25395536

  1. Climate Warming and Drought Effects on Pinus and Juniperus Species: Contrasting Drought Tolerance Traits Limit Function and Growth in Tree Seedlings 

    E-print Network

    Lenoir, Katherine Judith

    2013-04-29

    Junipers and pines exhibit contrasting patterns of growth decline and mortality with climate change-type warming and drought; yet, the underlying physiological mechanisms are not fully understood. Does warming exacerbate the effects of drought...

  2. Warm dense matter study at Matter in Extreme Conditions (MEC) Instrument with LCLS in SLAC

    NASA Astrophysics Data System (ADS)

    Lee, Hae Ja; Nagler, Bob

    2011-06-01

    The Matter in Extreme Conditions (MEC) instrument is being designed to study warm dense matter and high energy density matter. The lack of an appropriate x-ray light source has led to a paucity of robust techniques to create and probe high energy density matter. With the very recent advent of a high peak brightness x-ray source, the LCLS, MEC instrument can deliver the capability of studying phenomena of solid material under extreme conditions. We will describe the LCLS Materials under MEC instrument as well as the warm dense matter experimental program at LCLS.

  3. Is equilibrium climate sensitivity the best predictor for future global warming? (Invited)

    NASA Astrophysics Data System (ADS)

    Rypdal, M.; Rypdal, K.

    2013-12-01

    When the climate system is subject to radiative forcing the planet is brought out of radiative balance and the thermal inertia of the planet makes the surface temperature lag behind the forcing. The time constant, which is the time for relaxation to a new equilibrium after a sudden change in forcing, has been considered to be an important parameter to determine. The equilibrium climate sensitivity Seq, the temperature raise per unit forcing after relaxation is complete, is another. In the industrialized epoch a major source for the present energy imbalance is the steady increase in anthropogenic forcing. If the climate system can be modeled as a hierarchy of interacting subsystems with increasing heat capacities and response times there will also be a hierarchy of climate sensitivities. One way of modeling this feature is to replace the standard exponentially decaying impulse-response function with one that is scale free, i.e., decaying like a power law. For a climate system which is subject only to random forcing modeled as a white Gaussian noise, the resulting climate variable is then a long-memory fractional Gaussian noise with a scale-free power spectral density. The final response to a step increase in the forcing is infinite for such a perfectly scale-free response function, since the response to an increase in the forcing will never saturate. This is of course unphysical, but rather than invalidating the scale-free response model it suggests the introduction of a frequency-dependent climate sensitivity S(f). Even in the exponential response model the amplitude response to an oscillation vanishes for high frequencies, but converges to Seq in the limit of low frequencies f. In the scale-free response model S(f) diverges in the low-frequency limit. We demonstrate that long-memory responses can explain important aspects of Northern hemisphere temperature variability over the last millennium and lead to new predictions of how much more warming there will be 'in the pipeline' in any given forcing scenario. The relation to scaling properties of local temperature data and spatial correlations in climate data is also discussed. References: Rypdal, M. and Rypdal, K.: Long-memory effects in linear-response models of Earth's temperature and implications for future global warming, submitted to J. Climate, http://arxiv.org/pdf/ 1305.5080v1.pdf, 2013. Rypdal, M. and Rypdal, K.: 'Predicting' northern hemisphere temperature for the previous millennium based on a parametric stochastic-dynamic model trained on the instrumental global temperature and forcing records, session PP012, this conference.

  4. Do cities simulate climate change? A comparison of herbivore response to urban and global warming

    USGS Publications Warehouse

    Youngsteadt, Elsa; Dale, Adam G.; Terando, Adam J.; Dunn, Robert R.; Frank, Steven D.

    2014-01-01

    Cities experience elevated temperature, CO2, and nitrogen deposition decades ahead of the global average, such that biological response to urbanization may predict response to future climate change. This hypothesis remains untested due to a lack of complementary urban and long-term observations. Here, we examine the response of an herbivore, the scale insect Melanaspis tenebricosa, to temperature in the context of an urban heat island, a series of historical temperature fluctuations, and recent climate warming. We survey M. tenebricosa on 55 urban street trees in Raleigh, NC, 342 herbarium specimens collected in the rural southeastern United States from 1895 to 2011, and at 20 rural forest sites represented by both modern (2013) and historical samples. We relate scale insect abundance to August temperatures and find that M. tenebricosa is most common in the hottest parts of the city, on historical specimens collected during warm time periods, and in present-day rural forests compared to the same sites when they were cooler. Scale insects reached their highest densities in the city, but abundance peaked at similar temperatures in urban and historical datasets and tracked temperature on a decadal scale. Although urban habitats are highly modified, species response to a key abiotic factor, temperature, was consistent across urban and rural-forest ecosystems. Cities may be an appropriate but underused system for developing and testing hypotheses about biological effects of climate change. Future work should test the applicability of this model to other groups of organisms.

  5. Climate warming may facilitate invasion of the exotic shrub Lantana camara.

    PubMed

    Zhang, Qiaoying; Zhang, Yunchun; Peng, Shaolin; Zobel, Kristjan

    2014-01-01

    Plant species show different responses to the elevated temperatures that are resulting from global climate change, depending on their ecological and physiological characteristics. The highly invasive shrub Lantana camara occurs between the latitudes of 35 °N and 35 °S. According to current and future climate scenarios predicted by the CLIMEX model, climatically suitable areas for L. camara are projected to contract globally, despite expansions in some areas. The objective of this study was to test those predictions, using a pot experiment in which branch cuttings were grown at three different temperatures (22 °C, 26 °C and 30 °C). We hypothesized that warming would facilitate the invasiveness of L. camara. In response to rising temperatures, the total biomass of L. camara did increase. Plants allocated more biomass to stems and enlarged their leaves more at 26 °C and 30 °C, which promoted light capture and assimilation. They did not appear to be stressed by higher temperatures, in fact photosynthesis and assimilation were enhanced. Using lettuce (Lactuca sativa) as a receptor plant in a bioassay experiment, we also tested the phytotoxicity of L. camara leachate at different temperatures. All aqueous extracts from fresh leaves significantly inhibited the germination and seedling growth of lettuce, and the allelopathic effects became stronger with increasing temperature. Our results provide key evidence that elevated temperature led to significant increases in growth along with physiological and allelopathic effects, which together indicate that global warming facilitates the invasion of L. camara. PMID:25184224

  6. Do cities simulate climate change? A comparison of herbivore response to urban and global warming.

    PubMed

    Youngsteadt, Elsa; Dale, Adam G; Terando, Adam J; Dunn, Robert R; Frank, Steven D

    2015-01-01

    Cities experience elevated temperature, CO2 , and nitrogen deposition decades ahead of the global average, such that biological response to urbanization may predict response to future climate change. This hypothesis remains untested due to a lack of complementary urban and long-term observations. Here, we examine the response of an herbivore, the scale insect Melanaspis tenebricosa, to temperature in the context of an urban heat island, a series of historical temperature fluctuations, and recent climate warming. We survey M. tenebricosa on 55 urban street trees in Raleigh, NC, 342 herbarium specimens collected in the rural southeastern United States from 1895 to 2011, and at 20 rural forest sites represented by both modern (2013) and historical samples. We relate scale insect abundance to August temperatures and find that M. tenebricosa is most common in the hottest parts of the city, on historical specimens collected during warm time periods, and in present-day rural forests compared to the same sites when they were cooler. Scale insects reached their highest densities in the city, but abundance peaked at similar temperatures in urban and historical datasets and tracked temperature on a decadal scale. Although urban habitats are highly modified, species response to a key abiotic factor, temperature, was consistent across urban and rural-forest ecosystems. Cities may be an appropriate but underused system for developing and testing hypotheses about biological effects of climate change. Future work should test the applicability of this model to other groups of organisms. PMID:25163424

  7. Differentiated Responses of Apple Tree Floral Phenology to Global Warming in Contrasting Climatic Regions

    PubMed Central

    Legave, Jean-Michel; Guédon, Yann; Malagi, Gustavo; El Yaacoubi, Adnane; Bonhomme, Marc

    2015-01-01

    The responses of flowering phenology to temperature increases in temperate fruit trees have rarely been investigated in contrasting climatic regions. This is an appropriate framework for highlighting varying responses to diverse warming contexts, which would potentially combine chill accumulation (CA) declines and heat accumulation (HA) increases. To examine this issue, a data set was constituted in apple tree from flowering dates collected for two phenological stages of three cultivars in seven climate-contrasting temperate regions of Western Europe and in three mild regions, one in Northern Morocco and two in Southern Brazil. Multiple change-point models were applied to flowering date series, as well as to corresponding series of mean temperature during two successive periods, respectively determining for the fulfillment of chill and heat requirements. A new overview in space and time of flowering date changes was provided in apple tree highlighting not only flowering date advances as in previous studies but also stationary flowering date series. At global scale, differentiated flowering time patterns result from varying interactions between contrasting thermal determinisms of flowering dates and contrasting warming contexts. This may explain flowering date advances in most of European regions and in Morocco vs. stationary flowering date series in the Brazilian regions. A notable exception in Europe was found in the French Mediterranean region where the flowering date series was stationary. While the flowering duration series were stationary whatever the region, the flowering durations were far longer in mild regions compared to temperate regions. Our findings suggest a new warming vulnerability in temperate Mediterranean regions, which could shift toward responding more to chill decline and consequently experience late and extended flowering under future warming scenarios. PMID:26697028

  8. Differentiated Responses of Apple Tree Floral Phenology to Global Warming in Contrasting Climatic Regions.

    PubMed

    Legave, Jean-Michel; Guédon, Yann; Malagi, Gustavo; El Yaacoubi, Adnane; Bonhomme, Marc

    2015-01-01

    The responses of flowering phenology to temperature increases in temperate fruit trees have rarely been investigated in contrasting climatic regions. This is an appropriate framework for highlighting varying responses to diverse warming contexts, which would potentially combine chill accumulation (CA) declines and heat accumulation (HA) increases. To examine this issue, a data set was constituted in apple tree from flowering dates collected for two phenological stages of three cultivars in seven climate-contrasting temperate regions of Western Europe and in three mild regions, one in Northern Morocco and two in Southern Brazil. Multiple change-point models were applied to flowering date series, as well as to corresponding series of mean temperature during two successive periods, respectively determining for the fulfillment of chill and heat requirements. A new overview in space and time of flowering date changes was provided in apple tree highlighting not only flowering date advances as in previous studies but also stationary flowering date series. At global scale, differentiated flowering time patterns result from varying interactions between contrasting thermal determinisms of flowering dates and contrasting warming contexts. This may explain flowering date advances in most of European regions and in Morocco vs. stationary flowering date series in the Brazilian regions. A notable exception in Europe was found in the French Mediterranean region where the flowering date series was stationary. While the flowering duration series were stationary whatever the region, the flowering durations were far longer in mild regions compared to temperate regions. Our findings suggest a new warming vulnerability in temperate Mediterranean regions, which could shift toward responding more to chill decline and consequently experience late and extended flowering under future warming scenarios. PMID:26697028

  9. Icing Conditions Over Northern Eurasia in Changing Climate

    NASA Astrophysics Data System (ADS)

    Bulygina, O.; Arzhanova, N.; Groisman, P. Y.

    2013-12-01

    A general increase in atmospheric humidity is expected with global warming, projected with GCMs, reported with remote sensing and in situ observations (Trenberth et al. 2005; Dessler, and Davis 2010; IPCC 2007, Zhang et al. 2012.) In the Arctic this increase has been and will be especially prominent triggered by the dramatic retreat of the sea ice. In the warm season this retreat provides an abundant water vapor supply to the dry Arctic atmosphere. The contemporary sea ice changes are especially visible in the Eastern Hemisphere and after the two extremely anomalous low-ice years (2007 and 2012) it is right time to look for the impact of these changes in the high latitudinal hydrological cycle: first of all in the atmospheric humidity and precipitation changes. Usually, humidity (unless extremely high or low) does not critically affect the human activities and life style. However, in the high latitudes this characteristic has an additional facet: higher humidity causes higher ice condensation from the air (icing and hoar frost) on the infrastructure and transports in the absence of precipitation. The hoar frost and icing (in Russian: gololed) are measured at the Russian meteorological network and reports of icing of the wires are quantitative measurements. While hoar frost can be considered as a minor annoyance, icing may have important societal repercussions. In the Arctic icing occurs mostly during relatively warm months when atmosphere holds maximum amount of water vapor (and is projected to have more). Freezing rain and drizzle contribute to gololed formation and thus this variable (being above some thresholds) presents an important characteristic that can affect the infrastructure (communication lines elevated at the telegraph poles, antennas, etc.), became a Socially-Important climatic Variable (SIV). The former USSR observational program includes gololed among the documented weather phenomena and this allowed RIHMI to create Electronic Reference Book on Climate of the Russian Federation for the national territory. This Reference Book addresses the current state of these weather phenomena. However, the ongoing and projected humidity changes in the high latitudes will strongly affect the circum-polar area (land and ocean) and impact the frequency and intensity of these potentially dangerous weather phenomena across the entire extratropical land area. Therefore the goal of the present study is to quantify icing conditions over the northern Eurasia. Our analysis includes data of 958 Russian stations from 1977 to 2012. Regional analysis of gololed characteristics was carried out using quasi-homogeneous climatic regions. Maps (climatology, trends) are presented mostly for visualization purposes. The area-averaging technique using station values converted to anomalies with respect to a common reference period (in this study, from 1977 to 2012). Anomalies were arithmetically averaged first within 1N x 2E grid cells and thereafter by a weighted average value derived over the quasi-homogeneous climatic regions. This approach provides a more uniform spatial field for averaging.

  10. A paleoscience approach to estimating the effects of climatic warming on salmonid fisheries of the Columbia River Basin

    SciTech Connect

    Chatters, J.C.; Butler, V.L.; Scott, M.J.; Anderson, D.M.; Neitzel, D.A.

    1992-10-01

    To understand how climatic warming might affect salmonid populations, we are following a four-step procedure, incorporating paleoenvironmental data at the beginning and ending points, as follows. First, we used geomorphic, paleobotanical, and paleomalacological data to reconstruct stream conditions during the last 8000 years. Second, we estimated the effect on salmon of conditions extant approximately 6000 to 7000 radiocarbon years before present (B.P.), when temperatures were as much as 2{degrees}C warmer than at present. This became an analog of future warmer climate and its effects on spawning, incubation, and rearing parameters of the NPPC`s Tributary Parameter Model (TPM) for estimating salmoned production. Third, we ran the TPM in conjunction with the NPPC System Planning Model (SPM) to calculate the effect of these analog conditions on the population of returning adult fish in selected stream systems. Ultimately, we will run the models for all salmon-accessible subbasins of the Columbia River system. Finally, we are identifying fish remains obtained from archaeological sites along the Columbia River to compare variations in the taxonomic composition of ancient fish assemblages with model predictions.

  11. A paleoscience approach to estimating the effects of climatic warming on salmonid fisheries of the Columbia River Basin

    SciTech Connect

    Chatters, J.C.; Butler, V.L.; Scott, M.J.; Anderson, D.M.; Neitzel, D.A.

    1992-10-01

    To understand how climatic warming might affect salmonid populations, we are following a four-step procedure, incorporating paleoenvironmental data at the beginning and ending points, as follows. First, we used geomorphic, paleobotanical, and paleomalacological data to reconstruct stream conditions during the last 8000 years. Second, we estimated the effect on salmon of conditions extant approximately 6000 to 7000 radiocarbon years before present (B.P.), when temperatures were as much as 2[degrees]C warmer than at present. This became an analog of future warmer climate and its effects on spawning, incubation, and rearing parameters of the NPPC's Tributary Parameter Model (TPM) for estimating salmoned production. Third, we ran the TPM in conjunction with the NPPC System Planning Model (SPM) to calculate the effect of these analog conditions on the population of returning adult fish in selected stream systems. Ultimately, we will run the models for all salmon-accessible subbasins of the Columbia River system. Finally, we are identifying fish remains obtained from archaeological sites along the Columbia River to compare variations in the taxonomic composition of ancient fish assemblages with model predictions.

  12. Warm-Season North American Extreme Surface Air Temperature Relationships to Arctic Sea Ice Conditions

    NASA Astrophysics Data System (ADS)

    Budikova, D.; Chechi, L.

    2014-12-01

    Growing amount of evidence points to a notable impact of the changing Arctic cryosphere on remote climates. Recent studies propose a series of events that makes the connection between Arctic amplification/sea ice decline and increased frequency of extreme weather events in the mid-latitudes plausible. This study examines relationships between 1978-2013 spring (MAM) and summer (JJA) extreme surface air temperature (SAT) conditions across North America (NA) and simultaneous Arctic sea ice concentration (SIC) conditions. Seasonal summaries of daily frequency of occurrence of extreme SATs are correlated to simultaneous mean seasonal SIC anomalies. Low MAM SICs coincide with higher-than-normal incidence of cool nights/days across central US and Canada and eastern in Canada and lower-than-expected incidence of cool nights/days is observed westward from Nevada and Arizona. At this time, large portions of northern and eastern Canada and NE US coincide with decreased frequency of warmest days/nights and large sections of the US southwest show a significant increase in the frequency of warmest days/nights when SICs are low. SAT extremes continue to be related to SIC conditions into JJA across large portions of northern and eastern NA where lower-than-expected SICs coincide with significantly lower frequencies of cool nights/days and higher frequency of warm days/nights. Also examined are various simultaneously-occurring atmospheric and synoptic flow conditions that may begin to suggest potential mechanisms behind the observed relationships. Initial analyses indicate the observed relationships are reflected in mean monthly SATs and atmospheric thickness conditions, as well as 500 and 250 hPa geopotential height and zonal wind anomaly patterns. Both seasons display strong north-south meandering of the 500 hPa surface. During low MAM ice seasons the mid-tropospheric flow resembles the positive phase of the AO with a well-developed polar vortex that dips south of the Great Lakes; low SIC JJA seasons are characterized by a low-high-low flow over NA with a ridge over the central-eastern sector. Zonal flow at the 500 hPa level is significantly weakened in JJA over eastern NA. Areas with greatest flow anomalies are associated with regions that display most notable SAT extreme frequency deviations.

  13. Nitrogen partitioning in oak leaves depends on species, provenance, climate conditions and soil type.

    PubMed

    Hu, B; Simon, J; Kuster, T M; Arend, M; Siegwolf, R; Rennenberg, H

    2013-01-01

    Climate-tolerant tree species and/or provenances have to be selected to ensure the high productivity of managed forests in Central Europe under the prognosticated climate changes. For this purpose, we studied the responses of saplings from three oak species (i.e. Quercus robur, Q. petraea and Q. pubescens) and provenances of different climatic origin (i.e. low or high rainfall, low or high temperature habitats) with regard to leaf nitrogen (N) composition as a measure of N nutrition. Saplings were grown in model ecosystems on either calcareous or acidic soil and subjected to one of four treatments (control, drought, air warming or a combination of drought and air warming). Across species, oak N metabolism responded to the influence of drought and/or air warming with an increase in leaf amino acid N concentration at the expense of structural N. Moreover, provenances or species from drier habitats were more tolerant to the climate conditions applied, as indicated by an increase in amino acid N (comparing species) or soluble protein N (comparing provenances within a species). Furthermore, amino acid N concentrations of oak leaves were significantly higher on calcareous compared to acidic soil. From these results, it can be concluded that seeds from provenances or species originating from drier habitats and - if available - from calcareous soil types may provide a superior seed source for future forest establishment. PMID:22934888

  14. Disentangling Aerosol Cooling and Greenhouse Warming to Reveal Earth's Climate Sensitivity

    NASA Astrophysics Data System (ADS)

    Storelvmo, Trude; Leirvik, Thomas; Phillips, Petter; Lohmann, Ulrike; Wild, Martin

    2015-04-01

    Earth's climate sensitivity has been the subject of heated debate for decades, and recently spurred renewed interest after the latest IPCC assessment report suggested a downward adjustment of the most likely range of climate sensitivities. Here, we present a study based on the time period 1964 to 2010, which is unique in that it does not rely on global climate models (GCMs) in any way. The study uses surface observations of temperature and incoming solar radiation from approximately 1300 surface sites, along with observations of the equivalent CO2 concentration (CO2,eq) in the atmosphere, to produce a new best estimate for the transient climate sensitivity of 1.9K (95% confidence interval 1.2K - 2.7K). This is higher than other recent observation-based estimates, and is better aligned with the estimate of 1.8K and range (1.1K - 2.5K) derived from the latest generation of GCMs. The new estimate is produced by incorporating the observations in an energy balance framework, and by applying statistical methods that are standard in the field of Econometrics, but less common in climate studies. The study further suggests that about a third of the continental warming due to increasing CO2,eq was masked by aerosol cooling during the time period studied.

  15. Science blogging: RealClimate.org and the Global Warming debate

    NASA Astrophysics Data System (ADS)

    Schmidt, G. A.

    2006-12-01

    The media and public policy debate suffer from an extreme form of Attention Deficit Disorder. Compared to the daily news cycle, the progress of scientific debate within the peer-reviewed literature is extremely slow. This puts serious scientists who work in relatively politicised fields (global warming, evolution, stem cell research and the like) at a huge disadvantage when it comes to having their voices heard above the noise. Since Dec 2004, RealClimate.org has been operating as a group blog (a web-based journal) run by climate scientists for interested members of the public and the media. The aim has been to provide the context for climate-related news stories that is often missing in the mainstream media and to explain the basics of our field to the often confused, but curious, members of the public. In particular, it has provided rapid reaction to mis-uses and abuses of scientific results by policy advocates across the spectrum. Reactions to the blog have been overwhelmingly (but not uniformly) positive from both professionals in the media, the scientific community and the public. It has been described as the 'go-to site' for climate science in the New York Times, and received a Scientific American Science and Technology Web award in 2005. I will discuss what impacts RealClimate may have had and the pluses and minuses of trying to reach the public through this kind of outlet.

  16. Competitive and demographic leverage points of community shifts under climate warming.

    PubMed

    Sorte, Cascade J B; White, J Wilson

    2013-07-01

    Accelerating rates of climate change and a paucity of whole-community studies of climate impacts limit our ability to forecast shifts in ecosystem structure and dynamics, particularly because climate change can lead to idiosyncratic responses via both demographic effects and altered species interactions. We used a multispecies model to predict which processes and species' responses are likely to drive shifts in the composition of a space-limited benthic marine community. Our model was parametrized from experimental manipulations of the community. Model simulations indicated shifts in species dominance patterns as temperatures increase, with projected shifts in composition primarily owing to the temperature dependence of growth, mortality and competition for three critical species. By contrast, warming impacts on two other species (rendering them weaker competitors for space) and recruitment rates of all species were of lesser importance in determining projected community changes. Our analysis reveals the importance of temperature-dependent competitive interactions for predicting effects of changing climate on such communities. Furthermore, by identifying processes and species that could disproportionately leverage shifts in community composition, our results contribute to a mechanistic understanding of climate change impacts, thereby allowing more insightful predictions of future biodiversity patterns. PMID:23658199

  17. Data of cost-optimality and technical solutions for high energy performance buildings in warm climate

    PubMed Central

    Zacà, Ilaria; D’Agostino, Delia; Maria Congedo, Paolo; Baglivo, Cristina

    2015-01-01

    The data reported in this article refers to input and output information related to the research articles entitled Assessment of cost-optimality and technical solutions in high performance multi-residential buildings in the Mediterranean area by Zacà et al. (Assessment of cost-optimality and technical solutions in high performance multi-residential buildings in the Mediterranean area, in press.) and related to the research article Cost-optimal analysis and technical comparison between standard and high efficient mono residential buildings in a warm climate by Baglivo et al. (Energy, 2015, 10.1016/j.energy.2015.02.062, in press). PMID:26217793

  18. Elevation and connectivity define genetic refugia for mountain sheep as climate warms.

    PubMed

    Epps, Clinton W; Palsbøll, Per J; Wehausen, John D; Roderick, George K; McCullough, Dale R

    2006-12-01

    Global warming is predicted to affect the evolutionary potential of natural populations. We assessed genetic diversity of 25 populations of desert bighorn sheep (Ovis canadensis nelsoni) in southeastern California, where temperatures have increased and precipitation has decreased during the 20th century. Populations in low-elevation habitats had lower genetic diversity, presumably reflecting more fluctuations in population sizes and founder effects. Higher-elevation habitats acted as reservoirs of genetic diversity. However, genetic diversity was also affected by population connectivity, which has been disrupted by human development. Restoring population connectivity may be necessary to buffer the effects of climate change on this desert-adapted ungulate. PMID:17107466

  19. Warm Rain Processes over the Tropical Oceans and Implications on Climate Change: Results from TRMM and GEOS GCM

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Wu, H. T.

    2004-01-01

    In this talk, we will first show results from TRMM data regarding the characteristics of warm rains over the tropical oceans, and the dependence of rate of warm rain production on sea surface temperature. Results lead to the hypothesis that warm rain production efficiency, i.e., autoconversion, may be increased in a warm climate. We use the GEOS-II GCM to test this hypothesis. Our modeling results show that in a climate with increased rate of autoconversion, the total rain amount is increased, with warm rain contributing to larger portion of the increase. The abundant rainout of warm precipitation causes a reduction of low and middle cloud amount due to rainout, and reduced high clouds due to less water vapor available for ice-phase convection. However, clod radiation feedback caused by the increased rainfall efficiency, leads to differential vertical heating/cooling producing a more unstable atmosphere, allowing, more intense, but isolated penetrative convection, with contracted anvils to develop. Results also show that increased autoconversion reduces the convective adjustment time scale, resulting in faster recycling of atmospheric water. Most interestingly, the increased low level heating associated with warm rain leads to more energetic Madden and Julian oscillations in the tropics, with well-defined eastward propagation. While reducing the autoconversion leads to an abundant mix of westward and eastward tropical disturbances on daily to weekly time scales. The crucial link of precipitation microphysical processes to climate change including the effects of aerosols will be discussed.

  20. Warm Rain Processes Over the Tropical Oceans and Implications on Climate Change: Results from TRMM and GOES GCM

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Wu, H. T.

    2004-01-01

    In this talk, we will first show results from TRMM data regarding the characteristics of warm rains over the tropical oceans, and the dependence of rate of warm rain production on sea surface temperature. Results lead to the hypothesis that warm rain production efficiency, i.e., autoconversion, may be increased in a warm climate. We use the GEOS-II GCM to test this hypothesis. Our modeling results show that in a climate with increased rate of autoconversion, the total rain amount is increased, with warm rain contributing to a larger portion of the increase. The abundant rainout of warm precipitation causes a reduction of low and middle cloud amount due to rainout, and reduced high clouds due to less water vapor available for ice-phase convection. However, clod radiation feedback caused by the increased rainfall efficiency, leads to differential vertical heating/cooling producing a more unstable atmosphere, allowing, more intense, but isolated penetrative convection, with contracted anvils to develop. Results also show that increased autoconversion reduces the convective adjustment time scale, resulting in faster recycling of atmospheric water. Most interestingly, the increased low level heating associated with warm rain leads to more energetic Madden and Julian oscillations in the tropics, with well-defined eastward propagation. While reducing the autoconversion leads to an abundant mix of westward and eastward tropical disturbances on daily to weekly time scales. The crucial link of precipitation microphysical processes to climate change including the effects of aerosols will be discussed.

  1. Impact of a permanent El Niño (El Padre) and Indian Ocean Dipole in warm Pliocene climates

    USGS Publications Warehouse

    Shukla, Sonali P.; Chandler, Mark A.; Jonas, Jeff; Sohl, Linda E.; Mankoff, Ken; Dowsett, Harry J.

    2009-01-01

     Pliocene sea surface temperature data, as well as terrestrial precipitation and temperature proxies, indicate warmer than modern conditions in the eastern equatorial Pacific and imply permanent El Niño–like conditions with impacts similar to those of the 1997/1998 El Niño event. Here we use a general circulation model to examine the global-scale effects that result from imposing warm tropical sea surface temperature (SST) anomalies in both modern and Pliocene simulations. Observed SSTs from the 1997/1998 El Niño event were used for the anomalies and incorporate Pacific warming as well as a prominent Indian Ocean Dipole event. Both the permanent El Niño (also called El Padre) and Indian Ocean Dipole (IOD) conditions are necessary to reproduce temperature and precipitation patterns consistent with the global distribution of Pliocene proxy data. These patterns may result from the poleward propagation of planetary waves from the strong convection centers associated with the El Niño and IOD.

  2. Sensitivity of the Atmospheric Response to Warm Pool El Nino Events to Modeled SSTs and Future Climate Forcings

    NASA Technical Reports Server (NTRS)

    Hurwitz, Margaret M.; Garfinkel, Chaim I.; Newman, Paul A.; Oman, Luke D.

    2013-01-01

    Warm pool El Nino (WPEN) events are characterized by positive sea surface temperature (SST) anomalies in the central equatorial Pacific. Under present-day climate conditions, WPEN events generate poleward propagating wavetrains and enhance midlatitude planetary wave activity, weakening the stratospheric polar vortices. The late 21st century extratropical atmospheric response to WPEN events is investigated using the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM), version 2. GEOSCCM simulations are forced by projected late 21st century concentrations of greenhouse gases (GHGs) and ozone-depleting substances (ODSs) and by SSTs and sea ice concentrations from an existing ocean-atmosphere simulation. Despite known ocean-atmosphere model biases, the prescribed SST fields represent a best estimate of the structure of late 21st century WPEN events. The future Arctic vortex response is qualitatively similar to that observed in recent decades but is weaker in late winter. This response reflects the weaker SST forcing in the Nino 3.4 region and subsequently weaker Northern Hemisphere tropospheric teleconnections. The Antarctic stratosphere does not respond to WPEN events in a future climate, reflecting a change in tropospheric teleconnections: The meridional wavetrain weakens while a more zonal wavetrain originates near Australia. Sensitivity simulations show that a strong poleward wavetrain response to WPEN requires a strengthening and southeastward extension of the South Pacific Convergence Zone; this feature is not captured by the late 21st century modeled SSTs. Expected future increases in GHGs and decreases in ODSs do not affect the polar stratospheric responses to WPEN.

  3. Moisture rivals temperature in limiting photosynthesis by trees establishing beyond their cold-edge range limit under ambient and warmed conditions.

    PubMed

    Moyes, Andrew B; Germino, Matthew J; Kueppers, Lara M

    2015-09-01

    Climate change is altering plant species distributions globally, and warming is expected to promote uphill shifts in mountain trees. However, at many cold-edge range limits, such as alpine treelines in the western United States, tree establishment may be colimited by low temperature and low moisture, making recruitment patterns with warming difficult to predict. We measured response functions linking carbon (C) assimilation and temperature- and moisture-related microclimatic factors for limber pine (Pinus flexilis) seedlings growing in a heating × watering experiment within and above the alpine treeline. We then extrapolated these response functions using observed microclimate conditions to estimate the net effects of warming and associated soil drying on C assimilation across an entire growing season. Moisture and temperature limitations were each estimated to reduce potential growing season C gain from a theoretical upper limit by 15-30% (c. 50% combined). Warming above current treeline conditions provided relatively little benefit to modeled net assimilation, whereas assimilation was sensitive to either wetter or drier conditions. Summer precipitation may be at least as important as temperature in constraining C gain by establishing subalpine trees at and above current alpine treelines as seasonally dry subalpine and alpine ecosystems continue to warm. PMID:25902893

  4. Impact of climate warming-induced increase in drought stress on successional dynamic of a coniferous forest within a dry inner Alpine environment

    NASA Astrophysics Data System (ADS)

    Schuster, R.; Zeisler, B.; Oberhuber, W.

    2012-04-01

    Climate sensitivity of tree growth will effect the development of forest ecosystems under a warmer and drier climate by changing species composition and inducing shifts in forest distribution. We applied dendroclimatological techniques to determine impact of climate warming on radial stem growth of three native and widespread coniferous tree species of the central Austrian Alps (Norway spruce, Picea abies; European larch, Larix decidua; Scots pine, Pinus sylvestris), which grow intermixed at dry-mesic sites within a dry inner Alpine environment (750 m a.s.l., Tyrol, Austria). Time series of annual increments were developed from > 250 saplings and mature trees. Radial growth response to recent climate warming was explored by means of moving response functions (MRF) and evaluation of trends in basal area increment (BAI) for the period 1911 - 2009. Climate-growth relationships revealed significant differences among species in response to water availability. While precipitation in May - June favoured radial growth of spruce and larch, Scots pine growth mainly depended on April - May precipitation. Spruce growth was most sensitive to May - June temperature (inverse relationship). Although MRF coefficients indicated increasing drought sensitivity of all species, which is most likely related to intensified belowground competition for scarce water with increasing stand density and higher evapotranspiration rates due to climate warming, recent BAI trends strikingly differed among species. While BAI of larch was distinctly declining, spruce showed steadily increasing BAI and quite constant BAI was maintained in drought adapted Scots pine, although at lowest level of all species. Furthermore, more favourable growing conditions of spruce in recent decades are indicated by scattered natural regeneration and higher growth rates of younger trees during first decades of their lifespan. Because human interference and wildlife stock is negligible within the study area, results suggest a competitive advantage of shade-tolerant and shallow-rooted late successional spruce over early successional species, whereby the spruce`s competitive strength is most likely related to synergistic effects of shade-tolerance and efficient uptake of small rainfall events by fine roots distributed primarily in upper soil layers. On the other hand, strikingly decreasing trend in BAI of larch is suggested to be due to negative influence of climate warming on tree water status. We conclude that climate warming-induced increase in drought sensitivity changed competitive strength of co-occurring conifers due to differences in inherent adaptive capacity at a drought-prone inner Alpine site.

  5. A warm and wet Little Climatic Optimum and a cold and dry Little Ice Age in the southern Rocky Mountains, USA

    SciTech Connect

    Petersen, K.L.

    1992-05-01

    In the next century, increases in atmospheric trace gas concentration could warm the global average temperature beyond what it has ranged during the past century. Examination of larger-than-historic climatic changes that have occurred in the past in specific regions provides realistic context for evaluating such potential future changes. This paper has contrasted the climatic manifestation of the Little Climatic Optimum or Medieval Warm Period (AD 900--1300) with that of the Little Ice Age (AD 1300--1850) in the northern Colorado Plateau region of the southwestern USA. The zenith of the Anasazi occupation coincides with the former and their demise coincides with the latter, when conditions became too cold and especially dry (in the summer) to support upland dry farming. During the height of the Little Climatic Optimum the region was characterized by a relatively long growing season and greater winter and summer precipitation than that of today. This resulted in a relatively rapid development of a potential dry-farming belt that was twice as wide as the present and areas that cannot be dry farmed today were routinely farmed by the Anasazi. Such conditions would be beneficial to dry farmers in the Four Corners region if those conditions were repeated in the near future.

  6. Global Farm Animal Production and Global Warming: Impacting and Mitigating Climate Change

    PubMed Central

    Koneswaran, Gowri; Nierenberg, Danielle

    2008-01-01

    Background The farm animal sector is the single largest anthropogenic user of land, contributing to many environmental problems, including global warming and climate change. Objectives The aim of this study was to synthesize and expand upon existing data on the contribution of farm animal production to climate change. Methods We analyzed the scientific literature on farm animal production and documented greenhouse gas (GHG) emissions, as well as various mitigation strategies. Discussions An analysis of meat, egg, and milk production encompasses not only the direct rearing and slaughtering of animals, but also grain and fertilizer production for animal feed, waste storage and disposal, water use, and energy expenditures on farms and in transporting feed and finished animal products, among other key impacts of the production process as a whole. Conclusions Immediate and far-reaching changes in current animal agriculture practices and consumption patterns are both critical and timely if GHGs from the farm animal sector are to be mitigated. PMID:18470284

  7. Arctic shelf flooding: a negative feedback on climate warming during terminations

    NASA Astrophysics Data System (ADS)

    Blaschek, Michael; Renssen, Hans

    2013-04-01

    Glacial terminations are characterized by a strong rise in sea level related to melting ice sheets. This rise in sea level is not uniform all over the world, because regional effects (uplift and subsidence of coastal zones) are superimposed on global trends. For the Laptev Sea, Bauch et al. (2001) have shown that during the early Holocene the shelf area became flooded from 8.9 ka BP (-31 m) to 7.5 ka BP (-7 m, close to modern day coastline). An extrapolation of this result on the basis of modern bathymetry suggests that a far bigger area, covering the entire East Siberian Sea, became flooded at that time. This area is currently known as a sea-ice production zone (Tamura and Ohshima, 2010) and contributes significantly to the sea-ice exported from the Arctic through the Fram Strait (~20% of annual sea-ice area passing Fram Strait, Rigor and Colony, 1997). This leads to the following hypothesis: during times of lower sea levels, the coastline advances closer to the shelf break and reduces the amount of sea-ice production on these shelves, reducing sea-ice volume and export through Fram Strait and causing the sea-ice extent to retreat in the Nordic Seas, yielding warmer and saltier sea surface conditions. We have tested this hypothesis in a ocean-sea-ice-atmosphere coupled model of intermediate complexity (LOVECLIM), thereby focusing on an early Holocene (9 ka BP) test case. We use the results of 9 snapshot simulations with different model configurations, differing in land-sea-mask, manually prescribed ice sheets and melt fluxes from the Laurentide Ice sheet and the Greenland Ice sheet. Simulations with an unflooded East Siberian shelf show lower sea-ice production, a retreat of the sea-ice extent in the Nordic Seas and an increase in temperature and salinity on the northern East Greenland Current. Together with the retreating sea ice cover, local deep convection shifts from south of the Denmark Strait up to 9 degrees north, following the sea ice edge and resulting in heat release and surface warming during the entire year. Our analysis exhibits a surprising connection between increased sea-ice export through Fram Strait and changes in atmospheric winds that result from modifications in the atmospheric circulation, that are forced by changes in differential heating over the East Siberian Shelf and the Nordic Seas. This atmospheric teleconnection clearly shows that regional changes can affect hemispheric changes. In a first comparison with available sea-ice proxy reconstructions our results do not disagree, but show the necessity of increased temporal and spatial coverage of proxy reconstructions for future investigations. Our results indicate that shelf flooding had a significant impact on the climate during the early Holocene, namely reducing sea-ice cover and affecting atmospheric circulation. During terminations this can be considered to be a negative feedback on the progress of the termination, as a shelf area becomes flooded, sea-ice production and extent are likely to increase and reduce high latitude intake of orbitally-forced insolation, slowing down the warming trend. This can be the cause of observed cold reversals during warming phases in the continuous transformation of a glacial to an interglacial climate. This implies that shelf flooding should be taken into account when studying the climate dynamics during all glacial terminations. References Bauch, H.; Mueller-Lupp, T.; Taldenkova, E.; Spielhagen, R.; Kassens, H.; Grootes, P.; Thiede, J.; Heinemeier, J. & Petryashov, V. Chronology of the Holocene transgression at the North Siberian margin, Global and Planetary Change, 2001, 31, 125 - 139 Rigor, I. & Colony, R., Sea-ice production and transport of pollutants in the Laptev Sea, 1979-1993, Science of The Total Environment, Environmental Radioactivity in the Arctic, 1997, 202, 89-110 Tamura, T. & Ohshima, K. I., Mapping of sea ice production in the Arctic coastal polynyas, J. Geophys. Res., AGU, 2011, 116, C07030-

  8. How is climate warming altering the carbon cycle of a tundra ecosystem in the Siberian Arctic?

    NASA Astrophysics Data System (ADS)

    Belelli Marchesini, Luca; (Ko) van Huissteden, Jacobus; van der Molen, Michiel; Parmentier, Frans-Jan W.; Maximov, Trofim; Budishchev, Artem; Gallagher, Angela; (Han) Dolman, Albertus J.

    2015-04-01

    Climate has been warming over the the Arctic region with the strongest anomalies taking place in autumn and winter for the period 2000-2010, particularly in northern Eurasia. The quantification of the impact on climate warming on the degradation of permafrost and the associated potential release to the atmosphere of carbon stocked in the soil under the form of greenhouse gases, thus further increasing the radiative forcing of the atmosphere, is currently a matter of scientific debate. The positive trend in primary productivity in the last decades inferred by vegetation indexes (NDVI) and confirmed by observations on the enhanced growth of shrub vegetation represents indeed a contrasting process that, if prevalent could offset GHG emissions or even strengthen the carbon sink over the Arctic tundra. At the site of Kytalyk, in north-eastern Siberia, net fluxes of CO2 at ecosystem scale (NEE) have been monitored by eddy covariance technique since 2003. While presenting the results of the seasonal (snow free period) and inter-annual variability of NEE, conceived as the interplay between meteorological drivers and ecosystem responses, we test the role of climate as the main source of NEE variability in the last decade using a data oriented statistical approach. The impact of the timing and duration of the snow free period on the seasonal carbon budget is also considered. Finally, by including the results of continuous micrometeorological observations of methane fluxes taken during summer 2012, corroborated with seasonal CH4 budgets from two previous shorter campaigns (2008, 2009), as well as an experimentally determined estimate of dissolved organic carbon (DOC) flux, we provide an assessment of the carbon budget and its stability over time. The examined tundra ecosystem was found to sequester CO2 during the snow free season with relatively small inter-annual variability (-97.9±12.1gC m-2) during the last decade and without any evident trend despite the carbon uptake period tended to start earlier in the course of the year, potentially leading to a greater carbon sink. The large meteorological variability during the arctic summer controlled indeed the duration of the carbon uptake period and the flux rates with no clear evidence of changes in the response patterns of CO2 fluxes to climatic drivers (global radiation and air temperature) emerged from the analysis. The carbon loss associated with seasonal CH4 emissions and lateral DOC fluxes resulted equal for both terms and 6.2 gC m-2 in total. Hence the tundra ecosystem was found to act so far as a steady carbon sink exerting a negative feedback to climate warming.

  9. Constraining cloud responses to CO2 and warming in climate models: physical and statistical approaches

    NASA Astrophysics Data System (ADS)

    Sherwood, S. C.; Fuchs, D.; Bony, S.; Jean-Louis, D.

    2014-12-01

    We describe two avenues for constraining the sensitivity of the climate system to external perturbations, using present-day observations. The first is physically motivated, based on recently published work showing that differences in the simulated strength of convective mixing between the lower and middle tropical troposphere explain about half of the variance in climate sensitivity estimated by 43 climate models. The apparent mechanism is that such mixing dehydrates the low-cloud layer at a rate that increases as the climate warms, and this rate of increase depends on the initial mixing strength, linking the mixing to cloud feedback. The mixing inferred from observations appears to be sufficiently strong to imply a climate sensitivity of more than 3 degrees for a doubling of carbon dioxide. This is significantly higher than the currently accepted lower bound of 1.5 degrees, thereby constraining model projections towards relatively severe future warming. However, this result would be wrong if there were an important feedback in the real world that was missing from all the models. The second approach is based on application of the fluctuation-dissipation theorem to climate models, to predict the three-dimensional equilibrium response to heating perturbations via a statistical model of the system fitted to data from a control run. We expand on previous applications of this technique for such problems by considering multivariate state vectors, showing that this improves skill and makes it possible to train skillful operators on data records of comparable length to what is available from satellite observations. We also present a new methodology for treating non-stationary processes, in particular the existence of a seasonal cycle, and show that we can obtain similar results with a realistic seasonal cycle as with an idealised non-seasonally-varying case. We focus specifically on the ability to predict how clouds in the model will respond to a forced climate change. Results indicate that the fluctuation-dissipation method may prove to be more useful than previously thought for predicting global forces responses from observed variability, although the skill varies significantly depending on the nature of the forcing perturbation.

  10. Subsurface warming in the subpolar North Atlantic during rapid climate events in the Early and Mid-Pleistocene

    NASA Astrophysics Data System (ADS)

    Hernández-Almeida, Iván; Sierro, Francisco; Cacho, Isabel; Abel Flores, José

    2014-05-01

    A new high-resolution reconstruction of the temperature and salinity of the subsurface waters using paired Mg/Ca-?18O measurements on the planktonic foraminifera Neogloboquadrina pachyderma sinistrorsa (sin.) was conducted on a deep-sea sediment core in the subpolar North Atlantic (Site U1314). This study aims to reconstruct millennial-scale subsurface hydrography variations during the Early and Mid-Pleistocene (MIS 31-19). These rapid climate events are characterized by abrupt shifts between warm/cold conditions, and ice-sheet oscillations, as evidenced by major ice rafting events recorded in the North Atlantic sediments (Hernández-Almeida et al., 2012), similar to those found during the Last Glacial period (Marcott et al, 2011). The Mg/Ca derived paleotemperature and salinity oscillations prior and during IRD discharges at Site U1314 are related to changes in intermediate circulation. The increases in Mg/Ca paleotemperatures and salinities during the IRD event are preceded by short episodes of cooling and freshening of subsurface waters. The response of the AMOC to this perturbation is an increased of warm and salty water coming from the south, transported to high latitudes in the North Atlantic beneath the thermocline. This process is accompanied by a southward shift in the convection cell from the Nordic Seas to the subpolar North Atlantic and better ventilation of the North Atlantic at mid-depths. Poleward transport of warm and salty subsurface subtropical waters causes intense basal melting and thinning of marine ice-shelves, that culminates in large-scale instability of the ice sheets, retreat of the grounding line and iceberg discharge. The mechanism proposed involves the coupling of the AMOC with ice-sheet dynamics, and would explain the presence of these fluctuations before the establishment of high-amplitude 100-kyr glacial cycles. Hernández-Almeida, I., Sierro, F.J., Cacho, I., Flores, J.A., 2012. Impact of suborbital climate changes in the North Atlantic on ice sheet dynamics at the Mid-Pleistocene Transition. Paleoceanography 27, PA3214. Marcott, S.A., Clark, P.U., Padman, L., Klinkhammer, G.P., Springer, S.R., Liu, Z., Otto-Bliesner, B.L., Carlson, A.E., Ungerer, A., Padman, J., He, F., Cheng, J., Schmittner, A., 2011. Ice-shelf collapse from subsurface warming as a trigger for Heinrich events. Proceedings of the National Academy of Sciences 108, 13415-13419

  11. Modeling dynamics of circum-arctic tundra plant communities in response to climate warming and grazing pressure

    NASA Astrophysics Data System (ADS)

    Yu, Q.; Epstein, H. E.; Walker, D. A.; Forbes, B. C.; Vors, L. S.

    2011-12-01

    The Arctic is a complex system with strong interconnectedness among system components. Understanding the responses of the arctic tundra biome to a changing climate requires knowledge of the complex interactions among climate, soils, and the biological system. In this study, we investigate the individual and interactive effects of projected climate change and reindeer/caribou grazing across a variety of climate zones and soil nutrient levels on tundra plant community dynamics using an arctic vegetation model - ArcVeg. Our research questions include: 1) How does soil nutrient availability affect tundra vegetation responses to projected climate warming? 2) How does grazing affect tundra vegetation responses? 3) How do interactions of soil nutrients, climate warming and grazing affect tundra vegetation? We based our simulations on A1B scenario temperature data from the Intergovernmental Panel on Climate Change (IPCC), soil organic nitrogen data from Terrestrial Ecosystem Model (TEM) simulations and grazing pressure derived from reindeer/caribou population data from the CircumArctic Rangifer Monitoring and Assessment Network (CARMA). We found that in general tundra communities responded to warming with increased plant biomass, but the magnitude of the response is affected by the bioclimate zones, warming magnitude, available soil nutrients and grazing pressures. Regions with greater soil organic nitrogen responded to warming with greater biomass increase, Low Arctic tundra tended to have greater biomass increase than High Arctic tundra due to greater shrub abundance. However, such responses are mitigated by grazing. Regions with greater reindeer population and thus greater grazing intensity tended to have stronger negative effects on plant responses to warming than regions with less grazing. For example, in Subzone D, total biomass and NPP increases due to warming were about 71% and 43% in an Alaskan low grazing-intensity region, but 63% and 36% in a northwestern Canada high grazing-intensity region. In Subzone C, although with similar warming magnitude, Yamal and Taymyr region being intensely grazed by reindeer responded with smaller total biomass increase (~68%) than a northwestern Canada low grazing-intensity region (~93%). Plant responses to warming may be a factor that determines the size of reindeer population and understanding how tundra plants respond to warming, grazing and their interactions will contribute to reindeer management practices.

  12. Extreme climatic events and their evolution under changing climatic conditions

    E-print Network

    that, with the exception of earthquakes, climate-related hazards take the heaviest toll on human life 11. E-mail address: Martin.Beniston@unifr.ch (M. Beniston). Global and Planetary Change 44 (2004) 1Q resulting from earthquakes, but more than 170 events related to climatic extremes, in particular windstorms

  13. Global warming and tropical cyclone climate in the western North Pacific

    NASA Astrophysics Data System (ADS)

    Kang, Nam-Young

    Violent tropical cyclones (TCs) continue to inflict serious impacts on national economies and welfare, but how they are responding to global warming has not been fully clarified. Here I construct an empirical framework that shows the observations supporting a strong link between rising global ocean warmth and increasing trade-off between TC intensity and frequency in the western North Pacific. Thermodynamic structure of the tropical western North Pacific with high global ocean warmth is characterized by convectively more unstable lower troposphere with greater heat and moisture, but this instability is simultaneously accompanied by anomalous high pressure in the middle and upper troposphere over the same region. Increasing trade-off level between TC intensity and frequency in a warmer year proves that this environment further inhibits the TC occurrences over the region, but TCs that form tend to discharge stored energy to upper troposphere with stronger intensities. By increasing the intensity threshold at higher levels we confirmed that the TC climate connection with global ocean warmth occurs throughout the strongest portion of TCs, and the environmental connection of the TC climate is more conspicuous in the extreme portion of TCs. Intensities at the strongest 10~% of the western North Pacific TCs are comparable to super typhoons on average, the increasing trade-off magnitude clearly suggests that super typhoons in a warmer year gets stronger. Conclusively, the negative collinear feature of the thermodynamics influences the portion of TCs at the highest intensities, and super typhoons are likely to become stronger at the expense of overall TC frequencies in a warmer world. The consequence of this finding is that record-breaking TC intensities occur at the expense of overall TC frequencies under global warming. TC activity is understood as a variation which is independent of global warming, and could be assumed to be an internal variability having no trend. Frequency variation and super typhoon intensity variation are regarded as the addition of global warming influence on TC activity variation. The structure depicts how a previous intensity record is overtaken and frequency falls continuously in the global warming environment in a linear perspective. A peak TC activity year when global ocean warmth is the highest ever is likely to experience a record-breaking intensity. In the same way, the least number of annual TCs may appear when a lull of TC activity occurs in the warmest year.

  14. Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming.

    PubMed

    Walter, K M; Zimov, S A; Chanton, J P; Verbyla, D; Chapin, F S

    2006-09-01

    Large uncertainties in the budget of atmospheric methane, an important greenhouse gas, limit the accuracy of climate change projections. Thaw lakes in North Siberia are known to emit methane, but the magnitude of these emissions remains uncertain because most methane is released through ebullition (bubbling), which is spatially and temporally variable. Here we report a new method of measuring ebullition and use it to quantify methane emissions from two thaw lakes in North Siberia. We show that ebullition accounts for 95 per cent of methane emissions from these lakes, and that methane flux from thaw lakes in our study region may be five times higher than previously estimated. Extrapolation of these fluxes indicates that thaw lakes in North Siberia emit 3.8 teragrams of methane per year, which increases present estimates of methane emissions from northern wetlands (< 6-40 teragrams per year; refs 1, 2, 4-6) by between 10 and 63 per cent. We find that thawing permafrost along lake margins accounts for most of the methane released from the lakes, and estimate that an expansion of thaw lakes between 1974 and 2000, which was concurrent with regional warming, increased methane emissions in our study region by 58 per cent. Furthermore, the Pleistocene age (35,260-42,900 years) of methane emitted from hotspots along thawing lake margins indicates that this positive feedback to climate warming has led to the release of old carbon stocks previously stored in permafrost. PMID:16957728

  15. Effect of climatic warming on the Pacific walrus, and potential modification of its helminth fauna.

    PubMed

    Rausch, Robert L; George, John C; Brower, Harry K

    2007-10-01

    The decreasing extent of sea-ice in the arctic basin as a consequence of climatic warming is modifying the behavior and diets of pagophilic pinnipeds, including the Pacific walrus, Odobenus rosmarus divergens Illiger, the species emphasized here. Mammals such as the walrus and bearded seal, Erignathus barbatus (Erxleben), cannot remain associated with the sea-ice, and continue to feed on their usual diet of benthic invertebrates inhabiting coastal waters to a depth of approximately 100 m, when the northwestward retreating ice reaches deep waters beyond the margins of the continental shelf. With reduction of their customary substrate (ice), the walrus has become more pelagic and preys more often on ringed seals, Phoca hispida Schreber. Dietary changes, with modifications of helminth faunas, may be induced by various factors. Increased consumption of mammals or their remains by walruses may lead to a higher prevalence of trichinellosis in them and to more frequent occurrence in indigenous peoples inhabiting the arctic coasts. To assess predicted effects on the composition of helminth fauna of the walrus, we recommend systematic surveys of their helminths as part of research on effects of climatic warming. PMID:18163371

  16. A Song of Our Warming Planet: Using Music to Communicate Critical Concepts in Climate Science

    NASA Astrophysics Data System (ADS)

    St George, S.; Crawford, D.; Reubold, T.

    2014-12-01

    When climate science is communicated to the broader public, many of its key findings are shared in the form of conceptual diagrams or information-dense data graphics. In this collaboration, we applied a data sonification approach to express NASA's global temperature record as a musical composition for the cello. The resulting piece, which we titled 'A Song of Our Warming Planet', transformed 133 years of annual global temperature anomalies into a haunting, atonal melody that stretched across almost all of the instrument's range. Since its release in June 2013, the song has been featured by several national and international media outlets, including the New York Times, the Weather Channel, and National Public Radio, and its accompanying video has received more than 140,000 views from nearly every corner of the world. We are currently preparing a new composition for string quartet that will add a geographic dimension to describe both the pace and place of global warming. We believe the success of our initial sonification project is testament to the power of music to reach audiences who respond less enthusiastically to traditional methods used to communicate climate science. We also imagine this approach could be applied more broadly to allow students to create novel, visceral, and memorable encounters with other aspects of the geophysical sciences.

  17. Biogeochemical plant-soil microbe feedback in response to climate warming in peatlands

    NASA Astrophysics Data System (ADS)

    Bragazza, Luca; Parisod, Julien; Buttler, Alexandre; Bardgett, Richard D.

    2013-03-01

    Peatlands act as global sinks of atmospheric carbon (C) through the accumulation of organic matter, primarily made up of decay-resistant litter of peat mosses. However, climate warming has been shown to promote vascular plant growth in peatlands, especially ericaceous shrubs. A change in vegetation cover is in turn expected to modify above-ground/below-ground interactions, but the biogeochemical mechanisms involved remain unknown. Here, by selecting peatlands at different altitudes to simulate a natural gradient of soil temperature, we show that the expansion of ericaceous shrubs with warming is associated with an increase of polyphenol content in both plant litter and pore water. In turn, this retards the release of nitrogen (N) from decomposing litter, increases the amount of dissolved organic N and reduces N immobilization by soil microbes. A decrease of soil water content with increasing temperature promotes the growth of fungi, which feeds back positively on ericaceous shrubs by facilitating the symbiotic acquisition of dissolved organic N. We also observed a higher release of labile C from vascular plant roots at higher soil temperatures, which promotes the microbial investment in C-degrading enzymes. Our data suggest that climate-induced changes in plant cover can reduce the productivity of peat mosses and potentially prime the decomposition of organic matter by affecting the stoichiometry of soil enzymatic activity.

  18. Warming the nursing education climate for traditional-age learners who are male.

    PubMed

    Bell-Scriber, Marietta J

    2008-01-01

    For nurse educators to facilitate student learning and the achievement of desired cognitive, affective, and psychomotor outcomes, they need to be competent in recognizing the influence of gender, experience, and other factors on teaching and learning. A study was conducted in one academic institution to describe how traditional-age male learners' perceptions of the nursing education climate compare to perceptions of female learners. Interviews were conducted with a sample of four male and four female learners. Additional data from interviews with nurse educators, classroom observations, and a review of textbooks provided breadth and depth to their perceptions. Findings support a nursing education climate that is cooler to traditional-age male learners and warmer to traditional-age female learners. The main cooling factor for men was caused by nurse educators' characteristics and unsupportive behaviors. Additional factors inside and outside the education environment contributed to a cooler climate for the male learners. Based on these findings, strategies for nurse educators to warm the education climate for traditional-age male learners are presented. PMID:18575237

  19. Spatial heterogeneity in the timing of birch budburst in response to future climate warming in Ireland.

    PubMed

    Caffarra, Amelia; Zottele, Fabio; Gleeson, Emily; Donnelly, Alison

    2014-05-01

    In order to predict the impact of future climate warming on trees it is important to quantify the effect climate has on their development. Our understanding of the phenological response to environmental drivers has given rise to various mathematical models of the annual growth cycle of plants. These models simulate the timing of phenophases by quantifying the relationship between development and its triggers, typically temperature. In addition, other environmental variables have an important role in determining the timing of budburst. For example, photoperiod has been shown to have a strong influence on phenological events of a number of tree species, including Betula pubescens (birch). A recently developed model for birch (DORMPHOT), which integrates the effects of temperature and photoperiod on budburst, was applied to future temperature projections from a 19-member ensemble of regional climate simulations (on a 25 km grid) generated as part of the ENSEMBLES project, to simulate the timing of birch budburst in Ireland each year up to the end of the present century. Gridded temperature time series data from the climate simulations were used as input to the DORMPHOT model to simulate future budburst timing. The results showed an advancing trend in the timing of birch budburst over most regions in Ireland up to 2100. Interestingly, this trend appeared greater in the northeast of the country than in the southwest, where budburst is currently relatively early. These results could have implications for future forest planning, species distribution modeling, and the birch allergy season. PMID:24037345

  20. Spatial heterogeneity in the timing of birch budburst in response to future climate warming in Ireland

    NASA Astrophysics Data System (ADS)

    Caffarra, Amelia; Zottele, Fabio; Gleeson, Emily; Donnelly, Alison

    2014-05-01

    In order to predict the impact of future climate warming on trees it is important to quantify the effect climate has on their development. Our understanding of the phenological response to environmental drivers has given rise to various mathematical models of the annual growth cycle of plants. These models simulate the timing of phenophases by quantifying the relationship between development and its triggers, typically temperature. In addition, other environmental variables have an important role in determining the timing of budburst. For example, photoperiod has been shown to have a strong influence on phenological events of a number of tree species, including Betula pubescens (birch). A recently developed model for birch (DORMPHOT), which integrates the effects of temperature and photoperiod on budburst, was applied to future temperature projections from a 19-member ensemble of regional climate simulations (on a 25 km grid) generated as part of the ENSEMBLES project, to simulate the timing of birch budburst in Ireland each year up to the end of the present century. Gridded temperature time series data from the climate simulations were used as input to the DORMPHOT model to simulate future budburst timing. The results showed an advancing trend in the timing of birch budburst over most regions in Ireland up to 2100. Interestingly, this trend appeared greater in the northeast of the country than in the southwest, where budburst is currently relatively early. These results could have implications for future forest planning, species distribution modeling, and the birch allergy season.

  1. Recent rapid warming of the Antarctic Peninsula set in context with regional Holocene climate records (Invited)

    NASA Astrophysics Data System (ADS)

    Mulvaney, R.; Abram, N.; Arrowsmith, C.

    2013-12-01

    The Antarctic Peninsula is one of the most rapidly warming regions on Earth, with historical observations from local meteorological stations documenting warming equivalent to around 3.5°C per century. During recent decades ice shelves to the north-east of Antarctic Peninsula have been lost, causing an acceleration of the feeder glaciers that drain ice from the Antarctic Peninsula. However, marine sediment records taken from beneath the former Prince Gustav Channel and Larsen B ice shelves suggest that they were also absent during the middle of the Holocene, presumably before then being re-established, and then lost again recently. The paradox between modern observations of rapid climate change and retreating ice shelves, and yet an apparent absence of those same ice shelves only a few thousand years before today, cries out for a local paleoclimate record. This was achieved by a joint UK-French team who recovered an ice core to bedrock in 2008 from James Ross Island, situated at the north of the Antarctic Peninsula, close to the area where ice shelves have retreated. The 364m long core spans the whole of the period from the Last Glacial Maximum through to the present. Our temperature estimates, based on the record of water deuterium isotope variations in the ice, show that the northern Antarctic Peninsula experienced an early-Holocene climate optimum about 1.3°C warmer than present, followed by cooler stable temperatures, from about 9,200 to 2,500 years ago, that were similar to the modern-day levels. We find that the late Holocene development of ice shelves near James Ross Island was coincident with pronounced cooling from 2,500 to 600 years ago. Warming of the northern Antarctic Peninsula began around 600 years ago, with the rate becoming more rapid during the 20th century. We discuss the temperature record from the James Ross Island ice core together with other paleoclimate references from this region.

  2. 3D Numerical Simulation of the Geothermal Field of Permafrost at Salluit in Nunavik, Québec, in Response to Climate Warming. Research in Progress.

    NASA Astrophysics Data System (ADS)

    Fortier, R.; Allard, M.; Gagnon, O.

    2002-12-01

    The village of Salluit is located in the continuous permafrost zone in Nunavik, Québec. This Inuit community of about 1100 people is characterized by a fast population growth. The village lies in the bottom of a restricted valley flanked by steep rock walls. Most village infrastructures are built on frozen saline and ice-rich marine silts creating problematic ground conditions for infrastructures construction. For satisfying the fast population growth, a housing program is in progress but the available terrain with proper ground conditions for stable foundation is scarce and little is known on the permafrost conditions in the valley. During the construction of the airport of Salluit, a thermistor cable has been permanently buried in a rock outcrop. Regular temperature measurements have been carried out from 1987 and 1994, and from 2001 until now. During the first measurement interval, the permafrost temperature decreased steadily from -8 to -8.5 °C at a depth of 8 m. According to Environment Canada, the climate in that region of Canada was slowly cooling. However, this trend was reversed around 1997-1998 and some important warming recently occurred. In August 2001, the temperature measurements showed an increase of about 1.9 °C at the same depth. Moreover, a major active layer detachment failure occurred in the valley uphill in 1998 forcing the moving of twenty houses recently built. This landslide was probably triggered by the climate warming. Proper assessment of available terrain for the village expansion is therefore a major concern for the Inuit community of Salluit. Following the request of the provincial government, a thorough study for mapping the permafrost conditions and assessing the impacts of climate warming on permafrost conditions has been undertaken in 2002. The surveys carried out included deep sampling of permafrost, seismic reflection and ground penetrating radar profiling, and surface mapping supported by a detailed photo interpretation. The survey aims at providing information on the geological and geotechnical characteristics of permafrost. Thermistor cables in deep boreholes, meteorological stations, dataloggers for the measurement of surface temperature, and thermal probes have been also installed in the valley. Air photographs will be used to produce a digital terrain model of the valley. This integrated multi-technique approach is essential for properly assessing the permafrost conditions in the valley. The study will provide the data needed for the development of a 3D model of permafrost conditions in the valley. A 3D numerical simulation of the geothermal field of permafrost in the valley will be then undertaken. This simulation is a major challenge giving the size of the thermal field and the variability in permafrost conditions. The impacts of climate warming on the thermal field of permafrost will be simulated and predicted by forcing the surface temperature to increase following different scenarios of climate warming. It is planned to combine the geotechnical properties and the simulation of the geothermal field of permafrost in order to define threshold values of permafrost strength and slope instability and set a pre-warning scheme of permafrost temperature in case of further warming in the coming years. The monitoring of permafrost temperature will be continued in the future. If the scheme is reached, actions can be then undertaken to mitigate the impacts of climate warming on the infrastructures and protect the population of Salluit.

  3. Plants, Birds and Butterflies: Short-Term Responses of Species Communities to Climate Warming Vary by Taxon and with Altitude

    PubMed Central

    Roth, Tobias; Plattner, Matthias; Amrhein, Valentin

    2014-01-01

    As a consequence of climate warming, species usually shift their distribution towards higher latitudes or altitudes. Yet, it is unclear how different taxonomic groups may respond to climate warming over larger altitudinal ranges. Here, we used data from the national biodiversity monitoring program of Switzerland, collected over an altitudinal range of 2500 m. Within the short period of eight years (2003–2010), we found significant shifts in communities of vascular plants, butterflies and birds. At low altitudes, communities of all species groups changed towards warm-dwelling species, corresponding to an average uphill shift of 8 m, 38 m and 42 m in plant, butterfly and bird communities, respectively. However, rates of community changes decreased with altitude in plants and butterflies, while bird communities changed towards warm-dwelling species at all altitudes. We found no decrease in community variation with respect to temperature niches of species, suggesting that climate warming has not led to more homogenous communities. The different community changes depending on altitude could not be explained by different changes of air temperatures, since during the 16 years between 1995 and 2010, summer temperatures in Switzerland rose by about 0.07°C per year at all altitudes. We discuss that land-use changes or increased disturbances may have prevented alpine plant and butterfly communities from changing towards warm-dwelling species. However, the findings are also consistent with the hypothesis that unlike birds, many alpine plant species in a warming climate could find suitable habitats within just a few metres, due to the highly varied surface of alpine landscapes. Our results may thus support the idea that for plants and butterflies and on a short temporal scale, alpine landscapes are safer places than lowlands in a warming world. PMID:24416144

  4. Is the impact of future climate change on hydro-climatic conditions significant? - A climate change study for an Eastern European catchment area.

    NASA Astrophysics Data System (ADS)

    Pavlik, Dirk; Söhl, Dennis; Bernhofer, Christian

    2014-05-01

    The future change of climatic conditions is, among others, closely linked to future hydrological changes. One important aspect of these issues is the question of future availability of water resources. A changed climatic water balance, as indicator for potential water availability, has far-reaching consequences for the water cycle, hydrological conditions, ecology, water management, the energy business, agriculture and forestry, and for anthropogenic use of the river. We generated regional climate projections via dynamic downscaling for the catchment area of the Western Bug river in the border area of Poland, Belarus, and Ukraine. The hydro-climatic conditions of the past and their projected future changes in the catchment were analyzed based on 2m-temperature, precipitation, potential evaporation and climatic water balance. Up to the end of the century, the used IPCC scenarios B1 and A2 lead to warming for each month in the long-term mean, with highest warming rates in winter. Instead, precipitation does not change in the long-term yearly mean. However, the intra-annual distribution of monthly precipitation sums shifts with an increase in winter and a strong decrease in summer. Combined, this leads to a changed climatic water balance with a stronger deficit in summer and a higher gain in winter. Particular in the south-eastern part of the catchment, the summer deficit cannot be compensated within the annual cycle. It raised the question: are these changes statistically significant and thus robust for use in further impact studies? Using a significance analysis, we found, that climatic changes in temperature, precipitation and potential evaporation and thus the climatic water balance change is most significant for scenario A2 from 2071 to 2100. The temperature changes are significant throughout the year. For the other variables changes are most significant in the late summer months (July, August, and September) and the winter months (December, January, and February). In contrast, projected changes are hardly significant in the first period from 2021 to 2050. Only temperatures show most statistically significant changes. Weaker change signals in temperature, precipitation and potential evaporation lead also to weak climatic water balance changes in the first period. However, the projected changes in the first period are already indications of impending climatic changes in the catchment.

  5. Diagnosing Warm Frontal Cloud Formation in a GCM: A Novel Approach using Conditional Subsetting

    NASA Astrophysics Data System (ADS)

    Booth, J. F.; Naud, C. M.; Del Genio, A. D.

    2013-12-01

    This study analyzes characteristics of clouds and vertical motion across extratropical cyclone warm fronts in the NASA Goddard Institute for Space Studies General Circulation Model. The validity of the modeled clouds is assessed using a combination of satellite observations from CloudSat, CALIPSO and AMSR-E and the NASA-MERRA reanalysis. The analysis focuses on developing cyclones, to test the model's ability to generate their initial structure. To begin, the extratropical cyclones and their warm fronts are objectively identified and cyclone-local fields are mapped into a vertical transect centered on the surface warm front. To further isolate specific physics, the cyclones are separated using conditional subsetting based on additional cyclone-local variables, and the differences between the subset means are analyzed. Conditional subsets are created based on: (1, 2) the transect clouds and vertical motion, (3) the strength of the temperature gradient along the warm front, as well as the storm-local (4) wind speed and (5) precipitable water (PW). The analysis shows that the model does not generate enough frontal cloud, especially at low altitude. The subsetting results reveal that compared to the observations, the model exhibits a decoupling between cloud formation at high and low altitudes across warm fronts and a weak sensitivity to moisture. These issues are caused in part by the parameterized convection and assumptions in the stratiform cloud scheme that are valid in the subtropics. On the other hand, the model generates proper co-variability of low-altitude vertical motion and cloud at the warm front, and a joint dependence of cloudiness on wind and PW.

  6. Diagnosing Warm Frontal Cloud Formation in a GCM: A Novel Approach Using Conditional Subsetting

    NASA Technical Reports Server (NTRS)

    Booth, James F.; Naud, Catherine M.; DelGenio, Anthony D.

    2013-01-01

    This study analyzes characteristics of clouds and vertical motion across extratropical cyclone warm fronts in the NASA Goddard Institute for Space Studies general circulation model. The validity of the modeled clouds is assessed using a combination of satellite observations from CloudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E), and the NASA Modern-Era Retrospective Analysis for Research and Applications (MERRA) reanalysis. The analysis focuses on developing cyclones, to test the model's ability to generate their initial structure. To begin, the extratropical cyclones and their warm fronts are objectively identified and cyclone-local fields are mapped into a vertical transect centered on the surface warm front. To further isolate specific physics, the cyclones are separated using conditional subsetting based on additional cyclone-local variables, and the differences between the subset means are analyzed. Conditional subsets are created based on 1) the transect clouds and 2) vertical motion; 3) the strength of the temperature gradient along the warm front, as well as the storm-local 4) wind speed and 5) precipitable water (PW). The analysis shows that the model does not generate enough frontal cloud, especially at low altitude. The subsetting results reveal that, compared to the observations, the model exhibits a decoupling between cloud formation at high and low altitudes across warm fronts and a weak sensitivity to moisture. These issues are caused in part by the parameterized convection and assumptions in the stratiform cloud scheme that are valid in the subtropics. On the other hand, the model generates proper covariability of low-altitude vertical motion and cloud at the warm front and a joint dependence of cloudiness on wind and PW.

  7. Direct Expansion Air Conditioning System Selection for Hot & Humid Climates 

    E-print Network

    Browning, B. K.

    2002-01-01

    This paper discusses some of the difficulties of selecting direct expansion (DX) air conditioning systems to dehumidify conditioned spaces in hot & humid climates. It is a common opinion among designers that concerns of humidity control are best...

  8. Thermokarst processes in west-European loess series: new evidences for rapid climatic warming events during the Last Glacial

    NASA Astrophysics Data System (ADS)

    Antoine, Pierre; Moine, Olivier; Didier Rousseau, Denis; Hatté, Christine

    2013-04-01

    For a long time, the imprint of millennial climatic cycles (D/O cycles) in the Last Glacial loess sequences has been related to the alternation of loess layers and arctic brown soil horizons, especially between about 60 and 30 ka BP (± MIS 3). Nevertheless, owing to erosion gaps and strong reductions in the sedimentation rate, there are always less individual soil horizons than D/O cycles during the same period, which makes correlations very difficult. The discovery in the Nussloch loess sequence (Germany) of a thermokarst structure including well preserved vegetal remains, mollusc shells, and relicts of former ice wedge casts, provides new evidences for a rapid climatic warming at the origin of a major erosion event during the Middle Pleniglacial (±MIS 3). This elongated thermokarst erosion gully incised the underlying deposits. The presence of deformed ice-wedge relicts along its very sharp and irregular lower boundary indicates a formation by thermal erosion linked to a rapid melting of the permafrost ice. The analysis of the biological data (vegetal remains and mollusc shells) allows to evidence interstadial conditions strongly contrasting with the over- and underlying loess environments. Radiocarbon dates from wood remains (average 32.26 14C / ± 37.7 cal. BP) allow the correlation of the main thermokarst formation and infilling with GIS-8 from the GRIP ice core, following H4 event. Similar structures have been evidenced in other west-European loess sequences, most of them at the base of the Middle Pleniglacial formations. On the basis of a comparison with present day analogues from Alaska and Siberia permafrost areas, past "thermokarst events" are related to thermal erosion processes and proposed as markers for rapid warming periods in Last Glacial European loess sequences.

  9. Greenhouse to icehouse: Understanding the role of CO2 and non-CO2 forcings in warm climate intervals

    NASA Astrophysics Data System (ADS)

    Goldner, Aaron P.

    The Earth system has evolved significantly over the past 65 million years. A relatively ice free world dominated the Eocene ˜45 million years ago (Ma), until the late Oligocene (˜34 Ma) when the Antarctic Ice Sheet (AIS) developed in relatively short time period. Throughout the Oligocene and Miocene (23 to 5.3 Ma) temperatures gradually decreased as atmospheric CO2 continued to fall, vegetation biomes shifted, ocean circulation moved into its modern positions, and ocean gateways opened and closed. This transition from the warm and humid Eocene climate to the icehouse world we currently live has largely been attributed to a gradual decline in atmospheric CO 2. Acknowledging the fact that CO2 was the dominant driver in the gradual cooling over the last 65 million years, here we explore the less constrained feedbacks and forcings within the Earth system. These non-CO 2 forcings are important and could prove pivotal as we continue to constrain future climate prediction. Here we explore the climatic impact and forcing of the AIS, the oceanic response to AIS forcing, the temperature and precipitation patterns induced by changes in the El Nino southern Oscillation, and the impacts of El Nino and AIS forcing in the mid-Miocene Climatic Optimum (MMCO). Specifically, we find that the distribution of sea surface temperature (SSTs) in the eastern equatorial pacific has a teleconnected fingerprint throughout the world and more El Nino like conditions is a possible explanation of the wetter conditions in the mid-latitudes during the Pliocene and Miocene. The effective forcing and temperature impact of the Antarctic Ice Sheet depends on the mean climate state as modern climate responds differently to removing the AIS than at the Eocene-Oligocene transition and during the MMCO. The differing temperature and climate sensitivity response is largely controlled by low cloud and sea-ice feedbacks during these time periods and the efficacy of AIS forcing in the Eocene is not necessarily close to one and is likely to be model and state dependent. We also find that adding the AIS into the unglaciated Eocene world cools the deep ocean comparable to previous modelling studies that opened southern ocean gateways. The modelled delta18O anomaly induced by glaciation is comparable to the change detected in the proxy records across the transition suggesting that the AIS can induce changes in ocean circulation and thermal structure, thus reversing the hypothesis that gateways caused a reorganization of ocean circulation and glaciation across the EOT. Finally, Simulating the MMCO at 400 ppm CO2 using a recently released state of the art modelling framework produces a model data mismatch in global MAT and at high latitudes. The discrepancy is comparable to that introduced by a full doubling of CO2. It is noteworthy that including two of the most discussed Earth system feedbacks (El Nino and reduced ice volume) had small impacts on improving the model predictions even when we included uncertainty from orbital forcing. In summary, the Earth system is complex and explaining the warmth in past greenhouse climates requires many changes to boundary conditions, the right climate modelling framework, and better understanding of the non-CO 2 climate forcings.

  10. The palaeoclimatic significance of Eurasian Giant Salamanders (Cryptobranchidae: Zaissanurus, Andrias) - indications for elevated humidity in Central Asia during global warm periods (Eocene, late Oligocene warming, Miocene Climate Optimum)

    NASA Astrophysics Data System (ADS)

    Vasilyan, Davit; Böhme, Madelaine; Winklhofer, Michael

    2010-05-01

    Cryptobranchids represent a group of large sized (up to 1.8 m) tailed amphibians known since the Middle Jurassic (Gao & Shubin 2003). Two species are living today in eastern Eurasia: Andrias davidianus (China) and A. japonicus (Japan). Cenozoic Eurasian fossil giant salamanders are known with two genera and two or three species from over 30 localities, ranging from the Late Eocene to the Early Pliocene (Böhme & Ilg 2003). The Late Eocene species Zaissanurus beliajevae is restricted to the Central Asian Zaissan Basin (SE-Kazakhstan, 50°N, 85°E), whereas the Late Oligocene to Early Pliocene species Andrias scheuchzeri is distributed from Central Europe to the Zaissan Basin. In the latter basin the species occur during two periods; the latest Oligocene and the late Early to early Middle Miocene (Chkhikvadse 1982). Andrias scheuchzeri is osteological indistinguishable from both recent species, indicating a similar ecology (Westfahl 1958). To investigate the palaeoclimatic significance of giant salamanders we analyzed the climate within the present-day distribution area and at selected fossil localities with independent palaeoclimate record. Our results indicate that fossil and recent Andrias species occur in humid areas where the mean annual precipitation reach over 900 mm (900 - 1.300 mm). As a working hypothesis (assuming a similar ecology of Andrias and Zaissanurus) we interpret occurrences of both fossil Eurasian giant salamanders as indicative for humid palaeoclimatic conditions. Based on this assumption the Late Eocene, the latest Oligocene (late Oligocene warming) and the late Early to early Middle Miocene (Miocene Climatic Optimum) of Central Asia (Zaissan Basin) are periods of elevated humidity, suggesting a direct (positive) relationship between global climate and Central Asian humidity evolution. Böhme M., Ilg A. 2003: fosFARbase, www.wahre-staerke.com/ Chkhikvadze V.M. 1982. On the finding of fossil Cryptobranchidae in the USSR and Mongolia. Vertebrata Hungarica, 21: 63-67. Gao K.-Q., Shubin N.H. 2003. Earliest known crown-group Salamanders. Nature, 422: 424-428. Westphal F. 1958. Die Tertiären und rezenten Eurasiatischen Riesensalamander. Palaeontolographica Abt. A, 110: 20-92.

  11. Zonobiomes, forests, and major forest-forming conifers across Northern Eurasia by the end of the century under climate warming

    NASA Astrophysics Data System (ADS)

    Tchebakova, N.; Parfenova, E. I.; Shvetsov, E.; Soja, A. J.; Conard, S. G.

    2012-12-01

    Simulations of terrestrial ecosystems demonstrated globally the profound effects of the GCM-predicted climate change on their distribution at all hierarchical levels: zonobiomes, forests, and forest-forming tree species. We investigated progressions of potential vegetation cover, forest cover and ranges of forest-forming conifers across Northern Eurasia and Russia in the warming climate during the current century. We developed envelope-type static large-scale bioclimatic models predicting zonobiomes NEBioCliM, forests (ForCliM) and primary forest-forming conifer trees (TreeCliM)) from three bioclimatic indices (1) growing degree-days above 5oC, GDD5; (2) negative degree-days below 0oC, NDDo; and (3) an annual moisture index (ratio of growing degree days above 5oC to annual precipitation), AMI. No soil conditions except presence/absence of permafrost were taken into account in our models. Continuous permafrost was included in the models as limiting the forests and tree species distribution in interior Siberia. Each zonobiome, forest type and conifer distribution was mapped for the basic period 1960-1990 and for 2080 by coupling our bioclimatic models with bioclimatic indices and the permafrost distribution for the 1960-1990 and 2080 simulations. Climatic departures for the 2080 climate were derived from two climate change scenarios, the HadCM3 A2 and B1 (IPCC, 2007). Kappa (K) statistics were used to compare both the modeled vegetation and the conifer distributions in the contemporary climate to actual vegetation and forest maps. K-statistics proved that NEBioCliM accomplished a fair work in modeling zonobiomes across Russia. The tree species distributions also showed good match with the modeled ranges: 41% (Abies sibirica), 46% (Pinus sibirica), 71% (Pinus sylvestris), 75% (Picea spp.) and 78% (Larix spp.). Those matches might be higher because historically part of the primary conifer forests were replaced by secondary birch and aspen forests after large disturbances (clearcuts and wildfire). With these projected climates, the zonobiomes would need to shift far to the north in order to reach an equilibrium with the change in climate. Because future climate is predicted to be much warmer and drier, the future climate would be suitable for the forest-steppe ecotone and grasslands (up to 80%) rather than forests (less than 20%). Water stress tolerant light-needled taiga would have advantage over water-loving dark-needled taiga in a new climate. Permafrost wiould not retreat fast enough to make favorable habitats for dark taiga and L. dahurica taiga withstanding permafrost would remain the dominant forest type. Accumulated fire load due to increased tree mortality, especially at the southern forest border and in interior Siberia (Yakutia), together with an increase in fire weather would also initiate large fires facilitating vegetation progression towards an equilibrium with the climate.

  12. Dependence of warm and cold climate depiction on climate model resolution

    NASA Technical Reports Server (NTRS)

    Rind, David

    1988-01-01

    Climate change simulations run with two different resolutions (8 deg by 10 deg and 4 deg by 5 deg) of the NASA Goddard Institute for Space Studies model are used to investigate radiative, dynamical, and regional sensitivities to model grid size. The results show that model resolution affected two key processes in the control runs, moist convection and the nonlinear transfer of kinetic energy into the zonal mean flow. It was found that the finer resolution model has more penetrative convection but less convection overall, with the results that its temperature and wind structure were altered with respect to the coarser grid model.

  13. Climate Warming in Antarctica is Triggering Changes in Biodiversity and Terrestrial Ecosystems

    NASA Astrophysics Data System (ADS)

    Wall, D. H.

    2007-12-01

    Antarctica climate changes relating to ice and ocean currents have global impacts, but changes on terrestrial ecosystems in the Antarctic are less well known. This is partially due to the small area of exposed land, the apparent isolation, and lack of permanent residents. However, low diversity ecosystems, such as Antarctic polar deserts, are expected to be more vulnerable to global changes and are located in regions that are likely to see some of the greatest climate changes. Evidence is accumulating that terrestrial regions of Antarctica are experiencing substantial but variable responses to climate change and human disturbance. In the McMurdo Dry Valleys and in the rapidly warming Antarctic Peninsula region, temperature changes have a rippling effect that control habitat dynamics, species, carbon cycling, especially since these ecosystems are situated on a threshold between frozen and liquid water. Direct anthropogenic effects, including tourism and invasive species are also changing terrestrial communities but the magnitude and duration is dependent on numerous interacting factors. Global change scenarios incorporating species abundance, species traits, community change and monitoring of changes in biogeography will be important for determining alterations to ecosystem processes such as nutrient cycling.

  14. Persistent Cold Air Outbreaks over North America in a Warming Climate

    SciTech Connect

    Gao, Yang; Leung, Lai-Yung R.; Lu, Jian; Masato, Giacomo

    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 circulation 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.

  15. Persistent Cold Air Outbreaks over North America in a Warming Climate

    DOE PAGESBeta

    Gao, Yang; Leung, Lai-Yung R.; Lu, Jian; Masato, Giacomo

    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

  16. Evidence for a warm-humid climate in arid northwestern China during 40-30 ka BP

    NASA Astrophysics Data System (ADS)

    Yang, Bao; Shi, Yafeng; Braeuning, Achim; Wang, Jianxun

    2004-12-01

    Former shorelines and sedimentary records from several lake basins in northwestern China (Xinjiang, Qinghai) give evidence for warm and humid climatic conditions during 40-30 ka BP. Further indications of this favorable climate period are derived from palaeosols from the Ili loess and from cemented calcareous layers on the terraces of the Keriya River at the southern margin of the Tarim Basin and in the Badain Jaran Desert in Inner Mongolia. At that time, annual mean temperature in the Qaidam Basin was 2 °C higher and in the western part of Inner Mongolia even 2-3 °C higher than today. Precipitation in most parts of northwestern China was between 60-300 mm greater than today. These changes were probably a consequence of an increase in ocean surface temperature and evaporation resulting from a higher radiation input at middle and low latitudes caused by changes in the Earth's precessional cycle. As a result of these orbital changes, it is suggested that the intensified westerly circulation was responsible for increased moisture over northwestern China.

  17. Stand competition determines how different tree species will cope with a warming climate.

    PubMed

    Fernández-de-Uña, Laura; Cañellas, Isabel; Gea-Izquierdo, Guillermo

    2015-01-01

    Plant-plant interactions influence how forests cope with climate and contribute to modulate species response to future climate scenarios. We analysed the functional relationships between growth, climate and competition for Pinus sylvestris, Quercus pyrenaica and Quercus faginea to investigate how stand competition modifies forest sensitivity to climate and simulated how annual growth rates of these species with different drought tolerance would change throughout the 21st century. Dendroecological data from stands subjected to thinning were modelled using a novel multiplicative nonlinear approach to overcome biases related to the general assumption of a linear relationship between covariates and to better mimic the biological relationships involved. Growth always decreased exponentially with increasing competition, which explained more growth variability than climate in Q. faginea and P. sylvestris. The effect of precipitation was asymptotic in all cases, while the relationship between growth and temperature reached an optimum after which growth declined with warmer temperatures. Our growth projections indicate that the less drought-tolerant P. sylvestris would be more negatively affected by climate change than the studied sub-Mediterranean oaks. Q. faginea and P. sylvestris mean growth would decrease under all the climate change scenarios assessed. However, P. sylvestris growth would decline regardless of the competition level, whereas this decrease would be offset by reduced competition in Q. faginea. Conversely, Q. pyrenaica growth would remain similar to current rates, except for the warmest scenario. Our models shed light on the nature of the species-specific interaction between climate and competition and yield important implications for management. Assuming that individual growth is directly related to tree performance, trees under low competition would better withstand the warmer conditions predicted under climate change scenarios but in a variable manner depending on the species. Thinning following an exponential rule may be desirable to ensure long-term conservation of high-density Mediterranean woodlands, particularly in drought-limited sites. PMID:25826446

  18. Stand Competition Determines How Different Tree Species Will Cope with a Warming Climate

    PubMed Central

    Fernández-de-Uña, Laura; Cañellas, Isabel; Gea-Izquierdo, Guillermo

    2015-01-01

    Plant-plant interactions influence how forests cope with climate and contribute to modulate species response to future climate scenarios. We analysed the functional relationships between growth, climate and competition for Pinus sylvestris, Quercus pyrenaica and Quercus faginea to investigate how stand competition modifies forest sensitivity to climate and simulated how annual growth rates of these species with different drought tolerance would change throughout the 21st century. Dendroecological data from stands subjected to thinning were modelled using a novel multiplicative nonlinear approach to overcome biases related to the general assumption of a linear relationship between covariates and to better mimic the biological relationships involved. Growth always decreased exponentially with increasing competition, which explained more growth variability than climate in Q. faginea and P. sylvestris. The effect of precipitation was asymptotic in all cases, while the relationship between growth and temperature reached an optimum after which growth declined with warmer temperatures. Our growth projections indicate that the less drought-tolerant P. sylvestris would be more negatively affected by climate change than the studied sub-Mediterranean oaks. Q. faginea and P. sylvestris mean growth would decrease under all the climate change scenarios assessed. However, P. sylvestris growth would decline regardless of the competition level, whereas this decrease would be offset by reduced competition in Q. faginea. Conversely, Q. pyrenaica growth would remain similar to current rates, except for the warmest scenario. Our models shed light on the nature of the species-specific interaction between climate and competition and yield important implications for management. Assuming that individual growth is directly related to tree performance, trees under low competition would better withstand the warmer conditions predicted under climate change scenarios but in a variable manner depending on the species. Thinning following an exponential rule may be desirable to ensure long-term conservation of high-density Mediterranean woodlands, particularly in drought-limited sites. PMID:25826446

  19. Aspergillus steynii and Aspergillus westerdijkiae as potential risk of OTA contamination in food products in warm climates.

    PubMed

    Gil-Serna, Jessica; Patiño, Belén; Cortes, Laura; Gonzalez-Jaen, Maria Teresa; Vazquez, Covadonga

    2015-04-01

    Aspergillus steynii and Aspergillus westerdijkiae are the main ochratoxin A (OTA) producing species of Aspergillus section Circumdati. Due to its recent description, few data are available about the influence of ecophysiological factors on their growth and OTA production profiles. In this work, the effect of temperature (20, 24 and 28 °C) and water activity (aw) (0.928, 0.964 and 0.995) on growth, sporulation and OTA production by these fungi was examined in CYA and media prepared from paprika, green coffee, anise, grapes, maize and barley. Growth was positively affected by the highest temperature and aw values indicating that both species might be expected in warm climates or storage conditions. However, optimal growth conditions showed differences depending on the medium. OTA production was markedly affected by substrate and showed qualitative and quantitative differences. Both species, especially A. steynii, represent a great potential risk of OTA contamination due to their high production in a variety of conditions and substrates, in particular in barley and paprika-based media. Additionally, neither growth nor sporulation did result good indicators of OTA production by A. steynii or A. westerdijkiae; therefore, specific and highly-sensitive detection methods become essential tools for control strategies to reduce OTA risk by these species. PMID:25475281

  20. Biotic Response in Aquatic Reptiles (Testudines) during Earliest Eocene Climatic Warming

    NASA Astrophysics Data System (ADS)

    Holroyd, P. A.; Hutchison, J. H.

    2010-12-01

    The earliest Eocene is marked by significant events of global warming: the Paleocene-Eocene Thermal Maximum (PETM) at ~55.8 Ma and two short-lived events (ETM2 or Elmo and H2) approximately 2 Ma later. These environmental changes induced strong responses in the continental biota. Noteworthy changes in North American mid-latitude faunas and floras that are temporally correlated with earliest Eocene warming events include: increased diversity; turnover; and significant range changes, comprising both northward shifts in ranges of North American taxa as well as intercontinental dispersal across Holarctica. Evidence for these biotic changes comes directly from the fossil record and indirectly from phylogeographic analyses of molecular phylogenies of extant biota. To date, the stratigraphic record of biotic change has only been examined for the flora and terrestrial mammals. Data on reptiles and for continental aquatic systems are particularly lacking. In order to assess the impact of climate-mediated faunal change in aquatic systems during early Paleogene warming, we have focused on developing a detailed record of fossil turtles (Testudines) from the Bighorn Basin of Wyoming, where these records can be directly compared to similarly studied mammalian and floral data and to isotopic studies that provide independent proxies of climate change. Using genus-level occurrence data from more than 450 stratigraphically-constrained localities spanning ~2.5 Ma, we calculated first and last appearances, taxonomic richness, and relative abundance as measured by presence-absence (site occupancy). Among turtles, taxonomic richness increased episodically through the earliest Eocene with two new taxa appearing at the PETM, two immediately following it, and two at Biohorizon B, an interval associated with the younger hyperthermals. These new, immigrant taxa eventually comprised 40% of known generic richness. Phylogenetically, the inferred biogeographic source regions are southern North America and Asia, with an equal number of taxa originating in each area. Although immigrant taxa comprised less than half of the known earliest Eocene diversity, their relative dominance in these assemblages varied markedly. Within the PETM interval, immigrant taxa comprise nearly 70% of occurrences. Post-PETM, as temperatures cooled, immigrant taxa and taxa persisting from the Paleocene showed greater evenness, but immigrant taxa again became dominant with renewed warming. Among immigrant taxa, intercontinental dispersers are much more common than those that that dispersed from southern North America. These data are consistent with and stratigraphically correlative with significant changes in the mammalian fauna and flora of the Bighorn Basin and underline the importance of climatic change as a driver in these events. However, the magnitude and relative importance of intra- vs. intercontinental dispersal has not yet been fully examined in other taxonomic groups. The asymmetry of response following immigration that we observe in turtles may be taxon-specific, unique to aquatic systems, or may illustrate a more general pattern of how biotas respond to significant climate change.

  1. Effects of climatic warming on Lakes of the central boreal forest

    SciTech Connect

    Schindler, D.W.; Beaty, K.G.; Fee, E.J.; Cruikshank, D.R.; DeBruyn, E.R.; Findlay, D.L.; Linsey, G.A.; Shearer, J.A.; Stainton, M.P.; Turner, M.A. )

    1990-11-16

    Twenty years of climatic, hydrologic, and ecological records for the Experimental Lakes Area of northwestern Ontario show that air and lake temperatures have increased by 2{degree}C and the length of the ice-free season has increased by 3 weeks. Higher than normal evaporation and lower than average precipitation have decreased rates of water renewal in lakes. Concentrations of most chemicals have increased in both lakes and streams because of decreased water renewal and forest fires in the catchments. In Lake 239, populations and diversity of phytoplankton also increased, but primary production showed no consistent trend. Increased wind velocities, increased transparency, and increased exposure to wind of lakes in burned catchments caused thermoclines to deepen. As a result, summer habitats for cold stenothermic organisms like lake trout and opossum shrimp decreased. Our observations may provide a preview of the effects of increased greenhouse warming on boreal lakes. 27 refs., 1 fig.

  2. Comparing effects of climate warming, fire, and timber harvesting on a boreal forest landscape in northeastern China.

    PubMed

    Li, Xiaona; He, Hong S; Wu, Zhiwei; Liang, Yu; Schneiderman, Jeffrey E

    2013-01-01

    Forest management under a changing climate requires assessing the effects of climate warming and disturbance on the composition, age structure, and spatial patterns of tree species. We investigated these effects on a boreal forest in northeastern China using a factorial experimental design and simulation modeling. We used a spatially explicit forest landscape model (LANDIS) to evaluate the effects of three independent variables: climate (current and expected future), fire regime (current and increased fire), and timber harvesting (no harvest and legal harvest). Simulations indicate that this forested landscape would be significantly impacted under a changing climate. Climate warming would significantly increase the abundance of most trees, especially broadleaf species (aspen, poplar, and willow). However, climate warming would have less impact on the abundance of conifers, diversity of forest age structure, and variation in spatial landscape structure than burning and harvesting. Burning was the predominant influence in the abundance of conifers except larch and the abundance of trees in mid-stage. Harvesting impacts were greatest for the abundance of larch and birch, and the abundance of trees during establishment stage (1-40 years), early stage (41-80 years) and old- growth stage (>180 years). Disturbance by timber harvesting and burning may significantly alter forest ecosystem dynamics by increasing forest fragmentation and decreasing forest diversity. Results from the simulations provide insight into the long term management of this boreal forest. PMID:23573209

  3. Change in climate and nature over Toyama prefecture due to global warming

    NASA Astrophysics Data System (ADS)

    Hatsushika, H.; Kawasaki, K.; Oritani, T.; Kondo, T.; Mizoguchi, T.; Kido, M.; Tsuchihara, Y.; Wada, N.; Horikawa, K.

    2007-12-01

    Toyama prefecture is located in the center of the mainland of Japan and is surrounded by steep mountains called Tateyama at about 3,000m above sea level and by the deep Toyama bay at about 1,000m depth. In summer, since Pacific high covers mainland of Japan and East Asian summer monsoon brings a lot of rainfalls, climate in Toyama is suitable for cropping the highest qualified rice and vegetables. In winter, the dominant East Asian winter monsoon brings water from the Japan Sea by heavy snowfalls onto Tateyama. As the snow melts gradually from spring to early autumn, the abundant pure water is utilized for generating hydroelectric power and for a variety of other purposes, making it a vital resource for industries, agriculture, fishery, and human life as well as for wildlife on both sides of the plains and the mountains of Toyama. In recent, by the IPCC-AR4, influence of global warming is reported in many aspects of nature and human lives all over the world. However, we have yet to realize whether these signs are also appeared in Toyama. Therefore, we carried out statistical analyses to investigate change of nature, climate, and human lives in Toyama by global warming. Some of main results are as follows. Using the phenological data of a sample maple (Acer palmatum) tree growing at the garden in Toyama Local Meteorological Observatory, we analyzed that the leaf-color-change date is delayed ca. 20 days and the leaf-falling date is delayed ca. 10 days during recent 30 years. Using daily snowfall data between 1958 and 2007, we found that snow amounts and snowfall days are decreased significantly on the plains, while there is no trend on the mountain side. Using AMeDAS's hourly temperature data between 1978 and 2006, we detected increases in winter time minimum temperature, summer time maximum temperature, and "typical summer days" which is defined as total days that the daily maximum temperature exceeds 30 degree C. It can be inferred from these findings that the climate change over Toyama is occurring with no doubt, and it is necessary for us to make plans for adapting to the future change. Now, we are conducting future climate simulations of Toyama by downscaling some SRES scenario data. We will show some preliminary results of the simulation at the meeting.

  4. The Drivers of Climate Change -- Tracking Global Greenhouse Gas Trends and their Warming Influence

    NASA Astrophysics Data System (ADS)

    Butler, J. H.; Tans, P. P.; Montzka, S. A.; Dlugokencky, E. J.; Hall, B. D.; Masarie, K. A.; Elkins, J. W.; Dutton, G. S.; Miller, B. R.

    2014-12-01

    Of the National Physical Climate Indicators, two stand out as primary drivers of climate change - the Global Monthly Average of Carbon Dioxide Concentration and the Annual Greenhouse Gas Index. Both of these are products of high quality, long-term, globally distributed monitoring of greenhouse gases in the atmosphere. To support monitoring of the trends of these gases over decades, NOAA maintains the WMO World Calibration Scales for the major contributors to radiative forcing and its own universally accepted scales for most of the minor greenhouse gases. Maintenance of these scales over time ensures the consistency of measurements from decade to decade. Further quality control through use of internal and external comparisons of on-going measurements places tight constraints on spatial and temporal bias. By far the most influential greenhouse gas contributing to radiative forcing is carbon dioxide (CO2). Its amount at Mauna Loa is reported on-line daily and its global trend updated monthly on NOAA's global monitoring website and at climate.gov. This is one of the most closely watched records of atmospheric composition, as its accelerating rate of increase is a constant reminder that society has yet to deal successfully with its emissions of this gas. Much of CO2 emitted remains in the atmosphere for 1000s of years, which is why it is of substantial concern. But atmospheric CO2 is not alone in warming the planet and driving climate change. Many other gases contribute in a lesser way to this long-term trend and are captured along with CO2 in NOAA's Annual Greenhouse Gas Index (AGGI). The AGGI is a normalized compilation of the radiative forcing (RF) of five major long-lived greenhouse gases (96% of RF) and 15 minor gases (4% of RF). Because it does not include short lived gases (< ~10 years), it measures a robust RF trend that represents the warming influence society has already committed itself to living in. This presentation discusses the development of these two indexes and their national and global use.

  5. PUBLISHED ONLINE: 20 JULY 2014 | DOI: 10.1038/NCLIMATE2310 Well-estimated global surface warming in climate

    E-print Network

    Risbey, James S.

    are overestimating current temperature evolution. Such comparisons are not evidence against model trends becauseARTICLES PUBLISHED ONLINE: 20 JULY 2014 | DOI: 10.1038/NCLIMATE2310 Well-estimated global surface warming in climate projections selected for ENSO phase James S. Risbey1 *, Stephan Lewandowsky2

  6. Simulated climate-warming increases Coleoptera activity-densities and reduces community diversity in a cereal crop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To assess one likely effect of global warming, we experimentally increased the temperature and precipitation of a coleopteran community (mainly Carabidae) of an agro-ecosystem. We simulated climate change on a field of spring wheat by experimentally increasing the temperature by 2°C using infrared h...

  7. Global warming and climate change - predictive models for temperate and tropical regions

    SciTech Connect

    Malini, B.H.

    1997-12-31

    Based on the assumption of 4{degree}C increase of global temperature by the turn of 21st century due to the accumulation of greenhouse gases an attempt is made to study the possible variations in different climatic regimes. The predictive climatic water balance model for Hokkaido island of Japan (a temperate zone) indicates the possible occurrence of water deficit for two to three months, which is a unknown phenomenon in this region at present. Similarly, India which represents tropical region also will experience much drier climates with increased water deficit conditions. As a consequence, the thermal region of Hokkaido which at present is mostly Tundra and Micro thermal will change into a Meso thermal category. Similarly, the moisture regime which at present supports per humid (A2, A3 and A4) and Humid (B4) climates can support A1, B4, B3, B2 and B1 climates indicating a shift towards drier side of the climatic spectrum. Further, the predictive modes of both the regions have indicated increased evapotranspiration rates. Although there is not much of change in the overall thermal characteristics of the Indian region the moisture regime indicates a clear shift towards the aridity in the country.

  8. European warming linked to Greenland melting during the Last Interglacial North Atlantic climate optimum

    NASA Astrophysics Data System (ADS)

    Sanchez Goni, M.; Michel, E.; Desprat, S.; Carlson, A. E.; Naughton, F.; Fletcher, W. J.; Rossignol, L.

    2010-12-01

    Recent models and data synthesis suggest that the Last Interglacial North Atlantic warm optimum, ~130 ±2 ka, corresponded with a sea level stand of 4-9 m higher than that of the present-day implying that a substantial part of the Greenland Ice Sheet (GIS) melted at that time. This makes this interglacial a good analogue for understanding the impact of the ongoing global warming and GIS melting on the Atlantic Meridional Overturning Circulation (AMOC) and adjacent landmasses. Here we provide new insights on the impact of insolation and AMOC changes on western European ecosystems and climate and their regional transmission during an episode of GIS melting that can be considered somehow similar to that predicted for 2100 C.E. from IPCC projections. We have revisited three pollen-rich western European margin sequences distributed from 37 to 45°N, MD04-2845, MD95-2042 and MD99-2331, which span all of MIS 5 and are directly affected by the descending branch of the North Atlantic Drift. The analysis of these sequences allows us to directly correlate marine tracers of AMOC variability and changes in ice volume, sea surface temperature (SST), iceberg discharges and pollen-derived European vegetation and climate. The comparison of these observations with those inferred from other locations in the North Atlantic region directly affected by the AMOC and records from the Eirik Drift off southern Greenland document the response of North Atlantic climate to GIS melting during the Last Interglacial. Large and rapid increase in the Western European forest cover and mid-latitude North Atlantic SST at the beginning of MIS 5e benthic isotopic plateau following the YD-like event coincide with strong GIS melting. Despite continued GIS melting during this interval, AMOC strength gradually increases. The dramatic expansion of western European forest could be the result of both AMOC and insolation increase. Subsequently sustained warm SSTs and strong AMOC do not preclude the long term forest reduction which parallels insolation decrease. On millennial time scales, repeated decreases in GIS runoff occurred when Europe and the adjacent ocean cooled and AMOC strength weakened. Contrary to what would be expected if GIS melting triggering reduced AMOC with attendant forest reductions and cooling in western Europe and the North Atlantic Ocean, our study suggests that GIS melting increases at the same time as the subpolar and mid latitudes of the North Atlantic and adjacent landmasses experienced warming with AMOC reinvigoration. Given the potential analogue between the Last Interglacial and the end of this century, we suggest that in contrast to GIS melting weakening AMOC, increased radiative forcing leading to future GIS melting may be associated with increased AMOC strengthwarming of Western Europe and a larger extent of temperate forests, in the absence of human intervention.

  9. Using climate model experiments to explore difference between degrees of global warming: lessons from a study of African precipitation

    NASA Astrophysics Data System (ADS)

    James, Rachel; Washington, Richard

    2015-04-01

    A 2°C increase in global mean temperature (?Tg) has been widely adopted as a benchmark for dangerous climate change, and is currently being reviewed under the United Nations Framework Convention on Climate Change. However, there has been relatively little research into the implications of 2°C, or any other degree of global warming, for regional climate. This lack of research is particularly pressing in the case of vulnerable regions, including many in Africa. In recognition of this research gap, we conducted an in depth study of changes in African temperature and precipitation associated with 1°C, 1.5°C, 2°C, 3°C, 4°C, and beyond, using output from almost 400 climate model experiments: simulations from international modelling centres (CMIP3 and CMIP5), two perturbed physics ensembles, and a group of five regional models. The implications of global warming are different depending on which models are consulted, but each model consistently shows that temperature and precipitation anomalies are enhanced progressively with global warming. At 1°C, there is little significant change, but from 1.5°C or 2°C anomalies develop which grow in magnitude and spatial extent with global temperature, for example drying over Angola, and wetting in East Africa. The main difference between ?Tg intervals is in the magnitude and spatial extent of change. There do not appear to be rapid accelerations in the rate of change or trend reversals. This is not only true for lower levels of anthropogenic forcing, but also at higher degrees of warming up to 6°C. This finding has potential implications for policy. Given that larger changes in climate are likely to generate greater challenges for society, it suggests that global temperature should be limited to the lowest level possible. It does not imply that 2°C, or any other ?Tg increment, should be a preferred target from the perspective of regional climate. However, it is important to consider whether the approximately linear relationship between global warming and local climate change implied by the model experiments is reliable. It may be that the models are unable simulate feedbacks in the earth system which might lead to nonlinear change, due to their resolution and complexity. Analysis of earth system models run in long experiments with high levels of greenhouse gas forcing does reveal some nonlinear change. Further research might be needed to test the rate of change in global climate models before their results are used to infer difference between 1.5°C, 2°C, and other degrees of warming.

  10. Climate change under a scenario near 1.5 °C of global warming: monsoon intensification, ocean warming and steric sea level rise

    NASA Astrophysics Data System (ADS)

    Schewe, J.; Levermann, A.; Meinshausen, M.

    2011-03-01

    We present climatic consequences of the Representative Concentration Pathways (RCPs) using the coupled climate model CLIMBER-3?, which contains a statistical-dynamical atmosphere and a three-dimensional ocean model. We compare those with emulations of 19 state-of-the-art atmosphere-ocean general circulation models (AOGCM) using MAGICC6. The RCPs are designed as standard scenarios for the forthcoming IPCC Fifth Assessment Report to span the full range of future greenhouse gas (GHG) concentrations pathways currently discussed. The lowest of the RCP scenarios, RCP3-PD, is projected in CLIMBER-3? to imply a maximal warming by the middle of the 21st century slightly above 1.5 °C and a slow decline of temperatures thereafter, approaching today's level by 2500. We identify two mechanisms that slow down global cooling after GHG concentrations peak: The known inertia induced by mixing-related oceanic heat uptake; and a change in oceanic convection that enhances ocean heat loss in high latitudes, reducing the surface cooling rate by almost 50%. Steric sea level rise under the RCP3-PD scenario continues for 200 years after the peak in surface air temperatures, stabilizing around 2250 at 30 cm. This contrasts with around 1.3 m of steric sea level rise by 2250, and 2 m by 2500, under the highest scenario, RCP8.5. Maximum oceanic warming at intermediate depth (300-800 m) is found to exceed that of the sea surface by the second half of the 21st century under RCP3-PD. This intermediate-depth warming persists for centuries even after surface temperatures have returned to present-day values, with potential consequences for marine ecosystems, oceanic methane hydrates, and ice-shelf stability. Due to an enhanced land-ocean temperature contrast, all scenarios yield an intensification of monsoon rainfall under global warming.

  11. Climate change under a scenario near 1.5 °C of global warming: monsoon intensification, ocean warming and steric sea level rise

    NASA Astrophysics Data System (ADS)

    Schewe, J.; Levermann, A.; Meinshausen, M.

    2010-10-01

    We present climatic consequences of the Representative Concentration Pathways (RCPs) using the coupled climate model CLIMBER-3?, which contains a statistical-dynamical atmosphere and a three-dimensional ocean model. We compare those with emulations of 19 state-of-the-art atmosphere-ocean general circulation models (AOGCM) using MAGICC6. The RCPs are designed as standard scenarios for the forthcoming IPCC Fifth Assessment Report to span the full range of possible future greenhouse gas (GHG) concentrations pathways. The lowest of the RCP scenarios, RCP3-PD, is projected in CLIMBER-3? to imply a maximal warming by the middle of the 21st century slightly above 1.5 °C and a slow decline of temperatures thereafter, approaching today's level by 2500. We identify two mechanisms that slow down global cooling after GHG concentrations peak: The known inertia induced by mixing-related oceanic heat uptake; and a change in oceanic convection that enhances ocean heat loss in high latitudes, reducing the surface cooling rate by almost 50%. Steric sea level rise under the RCP3-PD scenario continues for 200 years after the peak in surface air temperatures, stabilizing around 2250 at 30 cm. This contrasts with around 2 m of steric sea level rise by 2500 under the highest scenario, RCP8.5. Maximum oceanic warming at intermediate depth (300-800 m) is found to exceed that of the sea surface by the second half of the 21st century under RCP3-PD. This intermediate-depth warming persists for centuries even after surface temperatures have returned to present-day values, with potential consequences for marine ecosystems, oceanic methane hydrates, and ice-shelf stability. Due to an enhanced land-ocean temperature contrast, all scenarios yield an intensification of monsoon rainfall under global warming.

  12. Equilibrium climate sensitivity in light of observations over the warming hiatus

    NASA Astrophysics Data System (ADS)

    Johansson, Daniel J. A.; O'Neill, Brian C.; Tebaldi, Claudia; Häggström, Olle

    2015-05-01

    A key uncertainty in projecting future climate change is the magnitude of equilibrium climate sensitivity (ECS), that is, the eventual increase in global annual average surface temperature in response to a doubling of atmospheric CO2 concentration. The lower bound of the likely range for ECS given in the IPCC Fifth Assessment Report (AR5; refs , ) was revised downwards to 1.5 °C, from 2 °C in its previous report, mainly as an effect of considering observations over the warming hiatus--the period of slowdown of global average temperature increase since the early 2000s. Here we analyse how estimates of ECS change as observations accumulate over time and estimate the contribution of potential causes to the hiatus. We find that including observations over the hiatus reduces the most likely value for ECS from 2.8 °C to 2.5 °C, but that the lower bound of the 90% range remains stable around 2 °C. We also find that the hiatus is primarily attributable to El Niño/Southern Oscillation-related variability and reduced solar forcing.

  13. Potential impacts of a warming climate on water availability in snow-dominated regions.

    PubMed

    Barnett, T P; Adam, J C; Lettenmaier, D P

    2005-11-17

    All currently available climate models predict a near-surface warming trend under the influence of rising levels of greenhouse gases in the atmosphere. In addition to the direct effects on climate--for example, on the frequency of heatwaves--this increase in surface temperatures has important consequences for the hydrological cycle, particularly in regions where water supply is currently dominated by melting snow or ice. In a warmer world, less winter precipitation falls as snow and the melting of winter snow occurs earlier in spring. Even without any changes in precipitation intensity, both of these effects lead to a shift in peak river runoff to winter and early spring, away from summer and autumn when demand is highest. Where storage capacities are not sufficient, much of the winter runoff will immediately be lost to the oceans. With more than one-sixth of the Earth's population relying on glaciers and seasonal snow packs for their water supply, the consequences of these hydrological changes for future water availability--predicted with high confidence and already diagnosed in some regions--are likely to be severe. PMID:16292301

  14. Strong atmospheric chemistry feedback to climate warming from Arctic methane emissions

    USGS Publications Warehouse

    Isaksen, Ivar S.A.; Gauss, Michael; Myhre, Gunnar; Walter Anthony, Katey M.; Ruppel, Carolyn

    2011-01-01

    The magnitude and feedbacks of future methane release from the Arctic region are unknown. Despite limited documentation of potential future releases associated with thawing permafrost and degassing methane hydrates, the large potential for future methane releases calls for improved understanding of the interaction of a changing climate with processes in the Arctic and chemical feedbacks in the atmosphere. Here we apply a “state of the art” atmospheric chemistry transport model to show that large emissions of CH4 would likely have an unexpectedly large impact on the chemical composition of the atmosphere and on radiative forcing (RF). The indirect contribution to RF of additional methane emission is particularly important. It is shown that if global methane emissions were to increase by factors of 2.5 and 5.2 above current emissions, the indirect contributions to RF would be about 250% and 400%, respectively, of the RF that can be attributed to directly emitted methane alone. Assuming several hypothetical scenarios of CH4 release associated with permafrost thaw, shallow marine hydrate degassing, and submarine landslides, we find a strong positive feedback on RF through atmospheric chemistry. In particular, the impact of CH4 is enhanced through increase of its lifetime, and of atmospheric abundances of ozone, stratospheric water vapor, and CO2 as a result of atmospheric chemical processes. Despite uncertainties in emission scenarios, our results provide a better understanding of the feedbacks in the atmospheric chemistry that would amplify climate warming.

  15. Darcy’s law predicts widespread forest mortality under climate warming

    USGS Publications Warehouse

    McDowell, Nate G.; Allen, Craig D.

    2015-01-01

    Drought and heat-induced tree mortality is accelerating in many forest biomes as a consequence of a warming climate, resulting in a threat to global forests unlike any in recorded history1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12. Forests store the majority of terrestrial carbon, thus their loss may have significant and sustained impacts on the global carbon cycle11,12. We use a hydraulic corollary to Darcy’s law, a core principle of vascular plant physiology13, to predict characteristics of plants that will survive and die during drought under warmer future climates. Plants that are tall with isohydric stomatal regulation, low hydraulic conductance, and high leaf area are most likely to die from future drought stress. Thus, tall trees of old-growth forests are at the greatest risk of loss, which has ominous implications for terrestrial carbon storage. This application of Darcy’s law indicates today’s forests generally should be replaced by shorter and more xeric plants, owing to future warmer droughts and associated wildfires and pest attacks. The Darcy’s corollary also provides a simple, robust framework for informing forest management interventions needed to promote the survival of current forests. Given the robustness of Darcy’s law for predictions of vascular plant function, we conclude with high certainty that today’s forests are going to be subject to continued increases in mortality rates that will result in substantial reorganization of their structure and carbon storage.

  16. Ocean subsurface warming as a mechanism for coupling Dansgaard-Oeschger climate cycles and ice-rafting events

    NASA Astrophysics Data System (ADS)

    Shaffer, Gary; Olsen, Steffen Malskær; Bjerrum, Christian J.

    2004-12-01

    Heinrich events have been attributed to surging of the Laurentide ice sheet every 7 thousand years or so during glacial time. These massive ice-rafting events only occurred during cold phases of millennial-scale, Dansgaard-Oeschger climate cycles. Other observed ice-rafting events, sourced from ice streams at various locations around the northern North Atlantic, occurred during all Dansgaard-Oeschger cold phases and led Heinrich events when the latter took place. Here it is suggested that ocean subsurface warming in the northern North Atlantic during the cold phases may provide the key to explaining these climate - ice rafting phasings. Such warming would lead to ice shelf melting and breakup. Without buttressing by ice shelves, ice streams may surge, leading to increased iceberg production. This interpretation is supported by results of a simplified, coupled climate model and by available sediment and ice sheet data.

  17. Vegetation types and climate conditions reflected by the modern phytolith assemblages in the subalpine Dalaoling Forest Reserve, central China

    NASA Astrophysics Data System (ADS)

    Traoré, Djakanibé Désiré; Gu, Yansheng; Liu, Humei; Shemsanga, Ceven; Ge, Jiwen

    2015-06-01

    This research describes modern phytolith records and distributions from subalpine surface soils in the Dalaoling Forest Reserve, and reveals its implications for local climate conditions with respect to the altitude gradient. Well-preserved phytolith morpho-types, assemblages, and climatic indices were used to study the relationship between local vegetation and climate conditions. The phytolith classification system is mainly based on the characteristics of detailed morpho-types described for anatomical terms, which are divided into seven groups: long cells, short cells, bulliform cells, hair cells, pteridophyte type, broad-leaved type, and gymnosperm type. Phytoliths originating from the Poaceae are composed of Pooideae (rondel and trapeziform), Panicoideae (bilobate, cross, and polylobate), Chloridoideae (short/square saddle), and Bambusoideae (oblong concave saddle). Based on the altitudinal distribution of the phytolith assemblages and the indices of aridity (Iph), climate (Ic), and tree cover density (D/P), five phytolith assemblage zones have revealed the five types of climatic conditions ranging from 1,169 m to 2,005 m in turn: warm-wet, warm-xeric to warm-mesic, warm-xeric to cool-mesic, cool-xeric, and cool-mesic to cool-xeric. The Bambusoideae, Panicoideae, and Chloridoideae are the dominant vegetation at the lower-middle of the mountains, while Pooideae is mainly distributed in the higher mountains. The close relationship between phytolith assembleages and changes of altitude gradient suggest that vegetation distribution patterns and plant ecology in the Dalaoling mountains are controlled by temperature and humidity conditions. Our results highlight the importance of phytolith records as reliable ecoclimatic indicators for vegetation ecology in subtropical regions.

  18. 24 CFR 3285.404 - Severe climatic conditions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Anchorage Against Wind § 3285.404 Severe climatic conditions. In frost-susceptible soil locations, ground anchor augers must be...

  19. 24 CFR 3285.404 - Severe climatic conditions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Anchorage Against Wind § 3285.404 Severe climatic conditions. In frost-susceptible soil locations, ground anchor augers must be...

  20. 24 CFR 3285.404 - Severe climatic conditions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Anchorage Against Wind § 3285.404 Severe climatic conditions. In frost-susceptible soil locations, ground anchor augers must be...

  1. Groundwater recharge simulation under the steady-state and transient climate conditions

    NASA Astrophysics Data System (ADS)

    Pozdniakov, S.; Lykhina, N.

    2010-03-01

    Groundwater recharge simulation under the steady-state and transient climate conditions Diffusive groundwater recharge is a vertical water flux through the water table, i.e. through the boundary between the unsaturated and saturated zones. This flux features temporal and spatial changes due to variations in the climatic conditions, landscape the state of vegetation, and the spatial variability of vadoze zone characteristics. In a changing climate the non-steady state series of climatic characteristics will affect on the groundwater recharge.. A well-tested approach to calculating water flux through the vadoze zone is the application of Richard’s equations for a heterogeneous one-domain porosity continuum with specially formulated atmospheric boundary conditions at the ground surface. In this approach the climatic parameters are reflected in upper boundary conditions, while the recharge series is the flux through the low boundary. In this work developed by authors code Surfbal that simulates water cycle at surface of topsoil to take into account the various condition of precipitation transformation at the surface in different seasons under different vegetation cover including snow accumulation in winter and melting in spring is used to generate upper boundary condition at surface of topsoil for world-wide known Hydrus-1D code (Simunek et al, 2008). To estimate the proposal climate change effect we performed Surfbal and Hydrus simulation using the steady state climatic condition and transient condition due to global warming on example of Moscow region, Russia. The following scenario of climate change in 21 century in Moscow region was selected: the annual temperature will increase on 4C during 100 year and annual precipitation will increase on 10% (Solomon et al, 2007). Within the year the maximum increasing of temperature and precipitation falls on winter time, while in middle of summer temperature will remain almost the same as observed now and monthly precipitation. For simulating climate input the weather generator LARSWG (Semenov and Barrow 1997) was trained for generation daily meteorological records for both steady state and transient climatic conditions and two 100 year of meteorological series of minimum and maximum of air temperature, solar radiation and precipitation were generated. The numerical experiment for studying of transient climate on groundwater was performed for typical vadoze zone parameters of western part of Moscow Artesian basin. As the result, the 100 years series of recharge were simulated. Examination of stochastic properties of simulated time-series and comparative analysis series for the transient and for the steady state conditions shows the trend of increasing of recharge in this region in transient climate. Analysis of daily and monthly simulated water balance shows that this increasing is result of winter snow melting and winter infiltration into thaw topsoil. This work was supported by Russian Foundation for Basic Research via grant 08-05-00720a REFERENCES Semenov M.A and Barrow E.M., 1997. Use of a stochastic weather generator in the development of climate change scenarios. Climatic Change, 35:397-414 Šim?nek, J., M. Th. van Genuchten, and M. Šejna, 2008. Development and applications of the HYDRUS and STANMOD software packages, and related codes, Vadose Zone Journal, doi:10.2136/VZJ2007.0077, Special Issue "Vadose Zone Modeling", 7(2), 587-600. Solomon, S., D. Qin, M. Manning, Technical Summary. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

  2. Global warming and climate forcing by recent albedo changes on Mars.

    PubMed

    Fenton, Lori K; Geissler, Paul E; Haberle, Robert M

    2007-04-01

    For hundreds of years, scientists have tracked the changing appearance of Mars, first by hand drawings and later by photographs. Because of this historical record, many classical albedo patterns have long been known to shift in appearance over time. Decadal variations of the martian surface albedo are generally attributed to removal and deposition of small amounts of relatively bright dust on the surface. Large swaths of the surface (up to 56 million km2) have been observed to darken or brighten by 10 per cent or more. It is unknown, however, how these albedo changes affect wind circulation, dust transport and the feedback between these processes and the martian climate. Here we present predictions from a Mars general circulation model, indicating that the observed interannual albedo alterations strongly influence the martian environment. Results indicate enhanced wind stress in recently darkened areas and decreased wind stress in brightened areas, producing a positive feedback system in which the albedo changes strengthen the winds that generate the changes. The simulations also predict a net annual global warming of surface air temperatures by approximately 0.65 K, enhancing dust lifting by increasing the likelihood of dust devil generation. The increase in global dust lifting by both wind stress and dust devils may affect the mechanisms that trigger large dust storm initiation, a poorly understood phenomenon, unique to Mars. In addition, predicted increases in summertime air temperatures at high southern latitudes would contribute to the rapid and steady scarp retreat that has been observed in the south polar residual ice for the past four Mars years. Our results suggest that documented albedo changes affect recent climate change and large-scale weather patterns on Mars, and thus albedo variations are a necessary component of future atmospheric and climate studies. PMID:17410170

  3. Global warming and climate forcing by recent albedo changes on Mars

    USGS Publications Warehouse

    Fenton, L.K.; Geissler, P.E.; Haberle, R.M.

    2007-01-01

    For hundreds of years, scientists have tracked the changing appearance of Mars, first by hand drawings and later by photographs. Because of this historical record, many classical albedo patterns have long been known to shift in appearance over time. Decadal variations of the martian surface albedo are generally attributed to removal and deposition of small amounts of relatively bright dust on the surface. Large swaths of the surface (up to 56 million km2) have been observed to darken or brighten by 10 per cent or more. It is unknown, however, how these albedo changes affect wind circulation, dust transport and the feedback between these processes and the martian climate. Here we present predictions from a Mars general circulation model, indicating that the observed interannual albedo alterations strongly influence the martian environment. Results indicate enhanced wind stress in recently darkened areas and decreased wind stress in brightened areas, producing a positive feedback system in which the albedo changes strengthen the winds that generate the changes. The simulations also predict a net annual global warming of surface air temperatures by ???0.65 K, enhancing dust lifting by increasing the likelihood of dust devil generation. The increase in global dust lifting by both wind stress and dust devils may affect the mechanisms that trigger large dust storm initiation, a poorly understood phenomenon, unique to Mars. In addition, predicted increases in summertime air temperatures at high southern latitudes would contribute to the rapid and steady scarp retreat that has been observed in the south polar residual ice for the past four Mars years. Our results suggest that documented albedo changes affect recent climate change and large-scale weather patterns on Mars, and thus albedo variations are a necessary component of future atmospheric and climate studies. ??2007 Nature Publishing Group.

  4. Limnological regime shifts caused by climate warming and Lesser Snow Goose population expansion in the western Hudson Bay Lowlands (Manitoba, Canada).

    PubMed

    MacDonald, Lauren A; Farquharson, Nicole; Merritt, Gillian; Fooks, Sam; Medeiros, Andrew S; Hall, Roland I; Wolfe, Brent B; Macrae, Merrin L; Sweetman, Jon N

    2015-02-01

    Shallow lakes are dominant features in subarctic and Arctic landscapes and are responsive to multiple stressors, which can lead to rapid changes in limnological regimes with consequences for aquatic resources. We address this theme in the coastal tundra region of Wapusk National Park, western Hudson Bay Lowlands (Canada), where climate has warmed during the past century and the Lesser Snow Goose (LSG; Chen caerulescens caerulescens) population has grown rapidly during the past ?40 years. Integration of limnological and paleolimnological analyses documents profound responses of productivity, nutrient cycling, and aquatic habitat to warming at three ponds ("WAP 12", "WAP 20", and "WAP 21?), and to LSG disturbance at the two ponds located in an active nesting area (WAP 20, WAP 21). Based on multiparameter analysis of (210)Pb-dated sediment records from all three ponds, a regime shift occurred between 1875 and 1900 CE marked by a transition from low productivity, turbid, and nutrient-poor conditions of the Little Ice Age to conditions of higher productivity, lower nitrogen availability, and the development of benthic biofilm habitat as a result of climate warming. Beginning in the mid-1970s, sediment records from WAP 20 and WAP 21 reveal a second regime shift characterized by accelerated productivity and increased nitrogen availability. Coupled with 3 years of limnological data, results suggest that increased productivity at WAP 20 and WAP 21 led to atmospheric CO2 invasion to meet algal photosynthetic demand. This limnological regime shift is attributed to an increase in the supply of catchment-derived nutrients from the arrival of LSG and their subsequent disturbance to the landscape. Collectively, findings discriminate the consequences of warming and LSG disturbance on tundra ponds from which we identify a suite of sensitive limnological and paleolimnological measures that can be utilized to inform aquatic ecosystem monitoring. PMID:25750718

  5. Limnological regime shifts caused by climate warming and Lesser Snow Goose population expansion in the western Hudson Bay Lowlands (Manitoba, Canada)

    PubMed Central

    MacDonald, Lauren A; Farquharson, Nicole; Merritt, Gillian; Fooks, Sam; Medeiros, Andrew S; Hall, Roland I; Wolfe, Brent B; Macrae, Merrin L; Sweetman, Jon N

    2015-01-01

    Shallow lakes are dominant features in subarctic and Arctic landscapes and are responsive to multiple stressors, which can lead to rapid changes in limnological regimes with consequences for aquatic resources. We address this theme in the coastal tundra region of Wapusk National Park, western Hudson Bay Lowlands (Canada), where climate has warmed during the past century and the Lesser Snow Goose (LSG; Chen caerulescens caerulescens) population has grown rapidly during the past ?40 years. Integration of limnological and paleolimnological analyses documents profound responses of productivity, nutrient cycling, and aquatic habitat to warming at three ponds (“WAP 12”, “WAP 20”, and “WAP 21?), and to LSG disturbance at the two ponds located in an active nesting area (WAP 20, WAP 21). Based on multiparameter analysis of 210Pb-dated sediment records from all three ponds, a regime shift occurred between 1875 and 1900 CE marked by a transition from low productivity, turbid, and nutrient-poor conditions of the Little Ice Age to conditions of higher productivity, lower nitrogen availability, and the development of benthic biofilm habitat as a result of climate warming. Beginning in the mid-1970s, sediment records from WAP 20 and WAP 21 reveal a second regime shift characterized by accelerated productivity and increased nitrogen availability. Coupled with 3 years of limnological data, results suggest that increased productivity at WAP 20 and WAP 21 led to atmospheric CO2 invasion to meet algal photosynthetic demand. This limnological regime shift is attributed to an increase in the supply of catchment-derived nutrients from the arrival of LSG and their subsequent disturbance to the landscape. Collectively, findings discriminate the consequences of warming and LSG disturbance on tundra ponds from which we identify a suite of sensitive limnological and paleolimnological measures that can be utilized to inform aquatic ecosystem monitoring. PMID:25750718

  6. Influence of Climate Warming on Arctic Mammals? New Insights from Ancient DNA Studies of the collared lemming Dicrostonyx torquatus.

    NASA Astrophysics Data System (ADS)

    Prost, Stefan; Smirnov, Nickolay; Fedorov, Vadim B.; Sommer, Robert S.; Stiller, Mathias; Nagel, Doris; Knapp, Michael; Hofreiter, Michael

    2010-05-01

    Global temperature increased by approximately half a degree (Celsius) within the last 150 years. Even this moderate warming had major impacts on Earth's ecological and biological systems, especially in the Arctic where the magnitude of abiotic changes even exceeds those in temperate and tropical biomes. Therefore, understanding the biological consequences of climate change on high latitudes is of critical importance for future conservation of the species living in this habitat. The past 25,000 years can be used as a model for such changes, as they were marked by prominent climatic changes that influenced geographic distribution, demographic history and pattern of genetic variation of many extant species. We sequenced ancient and modern DNA of the collared lemming (Dicrostonyx torquatus), which is a key species of the arctic biota, from a single site (Pymva Shor, Northern Pre Urals, Russia) to see if climate warming events after the Last Glacial Maximum (LGM) had detectable effects on the genetic variation of this arctic rodent species, which is strongly associated with cold and dry climate. Using three dimensional network reconstruction and model-based approaches such as Approximate Bayesian Computation and Markov Chain Monte Carlo based Bayesian inference we show that there is evidence for a population decline in the collared lemming following the LGM, with the population size dropping to a minimum during the Greenland Interstadial 1 (Blling/Allerd) warming phase at 14.5 kyrs BP. Our results show that previous climate warming events had a strong influence on collard lemming populations. A similar population reduction due to predicted future climate change would have severe effects on the arctic ecosystem, as collared lemmings are a key species in the trophic interactions and ecosystem processes in the Arctic.

  7. Influence of Climate Warming on Arctic Mammals? New Insights from Ancient DNA Studies of the Collared Lemming Dicrostonyx torquatus

    PubMed Central

    Prost, Stefan; Smirnov, Nickolay; Fedorov, Vadim B.; Sommer, Robert S.; Stiller, Mathias; Nagel, Doris; Knapp, Michael; Hofreiter, Michael

    2010-01-01

    Background Global temperature increased by approximately half a degree (Celsius) within the last 150 years. Even this moderate warming had major impacts on Earth's ecological and biological systems, especially in the Arctic where the magnitude of abiotic changes even exceeds those in temperate and tropical biomes. Therefore, understanding the biological consequences of climate change on high latitudes is of critical importance for future conservation of the species living in this habitat. The past 25,000 years can be used as a model for such changes, as they were marked by prominent climatic changes that influenced geographical distribution, demographic history and pattern of genetic variation of many extant species. We sequenced ancient and modern DNA of the collared lemming (Dicrostonyx torquatus), which is a key species of the arctic biota, from a single site (Pymva Shor, Northern Pre Urals, Russia) to see if climate warming events after the Last Glacial Maximum had detectable effects on the genetic variation of this arctic rodent species, which is strongly associated with a cold and dry climate. Results Using three dimensional network reconstructions we found a dramatic decline in genetic diversity following the LGM. Model-based approaches such as Approximate Bayesian Computation and Markov Chain Monte Carlo based Bayesian inference show that there is evidence for a population decline in the collared lemming following the LGM, with the population size dropping to a minimum during the Greenland Interstadial 1 (Bølling/Allerød) warming phase at 14.5 kyrs BP. Conclusion Our results show that previous climate warming events had a strong influence on genetic diversity and population size of collared lemmings. Due to its already severely compromised genetic diversity a similar population reduction as a result of the predicted future climate change could completely abolish the remaining genetic diversity in this population. Local population extinctions of collared lemmings would have severe effects on the arctic ecosystem, as collared lemmings are a key species in the trophic interactions and ecosystem processes in the Arctic. PMID:20523724

  8. Modeling the Effects of Climate Change on Permafrost in National Parks of Alaska: Will Permafrost Survive the Climate Warming of 21st Century?

    NASA Astrophysics Data System (ADS)

    Panda, S. K.; Marchenko, S. S.; Romanovsky, V. E.; Swanson, D. K.

    2014-12-01

    Permafrost underlies ~70% of all National Park Service administered land in Alaska and it provides a stable foundation to parks' ecosystems and wildlife habitats. However, the strength of this foundation is waning as its temperature is rising in response to recent climate warming. Consequently, thermokarst activities are on the rise and they are altering the parks' landscape, ecosystems, and wildlife habitats. In order to effectively respond to these changes park managers need up-to-date knowledge of the current permafrost temperature and distribution, and how they might evolve with changing climate in the future. To help decision makers understand and respond to the changing permafrost condition, we are modeling near-surface permafrost dynamics—permafrost temperature, distribution, and active layer thickness—in eight national parks of Alaska at a decadal time scale. We are using GIPL 1.0 model (Spatially Distributed Model of Permafrost Dynamics in Alaska), the best available climate inputs, and high-resolution (28 m) ecotype, soil landscape, and snow inputs. Here we present results for two national parks—Denali National Park and Preserve (DENA) and Wrangell-St. Elias National Park and Preserve (WRST). Areas underlain by glaciers and permanent ice-fields were excluded. In DENA, the model suggested near-surface permafrost in 51% of the park area for the 2000 decade, predicted its decline to 6% by 2050s, and 1% by 2090s. In WRST, the model suggested near-surface permafrost in 72% of the park area for the 2000 decade, predicted its decline to 42% by 2050s, and 15% by 2090s. In summary, the near-surface permafrost will likely be degrading in most parts of DENA and WRST towards the end of the current century except at higher elevations where climate models continue to project colder temperature. The modeled maps of DENA and WRST showed 86% and 95% agreement with the field observations of permafrost presence/ absence at 1375 and 430 sites, respectively. In conclusion, the modeled high-resolution permafrost maps show the effect of changing climate on near-surface permafrost. They offer decision makers a clear understanding of how near-surface permafrost distribution in the parks might change in the future, which was lacking up until now, to guide critical monitoring and management decisions.

  9. The interplay between knowledge, perceived efficacy, and concern about global warming and climate change: a one-year longitudinal study.

    PubMed

    Milfont, Taciano L

    2012-06-01

    If the long-term goal of limiting warming to less than 2°C is to be achieved, rapid and sustained reductions of greenhouse gas emissions are required. These reductions will demand political leadership and widespread public support for action on global warming and climate change. Public knowledge, level of concern, and perceived personal efficacy, in positively affecting these issues are key variables in understanding public support for mitigation action. Previous research has documented some contradictory associations between knowledge, personal efficacy, and concern about global warming and climate change, but these cross-sectional findings limit inferences about temporal stability and direction of influence. This study examines the relationships between these three variables over a one-year period and three waves with national data from New Zealand. Results showed a positive association between the variables, and the pattern of findings was stable and consistent across the three data points. More importantly, results indicate that concern mediates the influence of knowledge on personal efficacy. Knowing more about global warming and climate change increases overall concern about the risks of these issues, and this increased concern leads to greater perceived efficacy and responsibility to help solving them. Implications for risk communication are discussed. PMID:22489642

  10. Energy Partition From Various Climate Conditions And Land Use Types

    NASA Astrophysics Data System (ADS)

    Cheng, Chi-Han; Hsu2, Pang-Chi

    2015-04-01

    Investigating how energy partitions and what factors control energy exchange is critical for better understanding the hydrological cycle, boundary layer dynamics, and land -atmosphere coupling. Climate and land use conditions are the two main factors to control energy partitation. However, previous studies discussed energy partition and factors that controlled Bowen ratio (i.e., ratio of sensible heat flux to latent heat flux) in limited land use types and climate conditions. To provide a more comprehensive analysis over various climate and vegetation types, in this study, we studied eleven different land use types in the eight different climate zones within the United State. The results found out that the Mediterranean climate zone with dry summer season, dry arid (desert) climate zone, and the higher latitude area with severe winter would had higher Bowen ratio, lower precipitation and net radiation. In contrast, the humid climate zones had the lower Bowen ratio, higher net radiation and precipitation. Moreover, the higher Bowen ratio usually happened in the winter or early spring seasons. Regarding land conditions, it is found that soil moistures are the key factor to control Bowen ratio in the drier climate areas. Hence, the grassland and closed shrublands sites have higher Bowen ratio than deciduous broadleaf forests and evergreen needle-leaf forests sites' because of shallower root systems that lack access to the full storage of water in the vadose zone. However, in the humid areas, land use factors, such as stomatal resistance and leaf area, would play an important role in changing latent heat and sensible heat. Based on the tight relationships between Bowen ratio and conditions of climate and land use, we suggest that Bowen ratio could be a useful tool for understanding the potential feedbacks of changes in climate and land use to energy partition and exchange.

  11. The effect of abrupt climate changes and climate background conditions in Southern Europe during the last glacial

    NASA Astrophysics Data System (ADS)

    Knorr, Gregor; Martin-Puertas, Celia; Brauer, Achim; Lohmann, Gerrit

    2015-04-01

    The last glacial period is characterized by abrupt and large temperature shifts in Greenland and the North Atlantic realm. Pollen and sediment data from Lago Grande di Monticchio (MON) have demonstrated a clear imprint of these fluctuations operating at millennial time-scales. Interestingly, basic mean environmental condition changes with respect to temperature and precipitation occurred during MIS4, separating warm and dry conditions during MIS5 from relatively cold and humid conditions within MIS3. This general climate background shift is superposed by distinct millennial-scale variability at MON. Using a fully coupled atmosphere-ocean general circulation model applying boundary conditions at 32 ka BP and pre-industrial conditions as a surrogate for MIS3 and MIS5, we have simulated and analysed characteristic changes in Southern Europe during the last glacial. We find that changes in the mean state at MON are mainly related to a partial shift of the North Atlantic deep water (NADW) convection sites from the Nordic Seas to South of Iceland, the presence of the Fennoscandian ice sheet and lower greenhouse gas concentrations. These background characteristics provide the basis for enhanced zonal moisture transport from the eastern North Atlantic to Middle and Southern Europe. Furthermore, simulations of abrupt climate change scenarios show that a deactivation of the convection sites South of Iceland during MIS3 leads to cooler and dryer conditions at MON. Such temperature and precipitation changes are thought to provide a counter-acting effect on woody vegetation and associated pollen signals at MON. This is in contrast to the impact of abrupt climate perturbation scenarios during MIS5, where no significant precipitation changes are detected. Hence, the simulated changes and underlying mechanisms are largely consistent with the recorded proxy evidence with respect to both, mean state and millennial-scale changes.

  12. In situ carbon turnover dynamics and the role of soil microorganisms therein: a climate warming study in an Alpine ecosystem.

    PubMed

    Djukic, Ika; Zehetner, Franz; Watzinger, Andrea; Horacek, Micha; Gerzabek, Martin H

    2013-01-01

    Litter decomposition represents one of the largest fluxes in the global terrestrial carbon cycle. The aim of this study was to improve our understanding of the factors governing decomposition in alpine ecosystems and how their responses to changing environmental conditions change over time. Our study area stretches over an elevation gradient of 1000 m on the Hochschwab massif in the Northern Limestone Alps of Austria. We used high-to-low elevation soil translocation to simulate the combined effects of changing climatic conditions, shifting vegetation zones, and altered snow cover regimes. In original and translocated soils, we conducted in situ decomposition experiments with maize litter and studied carbon turnover dynamics as well as temporal response patterns of the pathways of carbon during microbial decomposition over a 2-year incubation period. A simulated mean annual soil warming (through down-slope translocation) of 1.5 and 2.7 °C, respectively, resulted in a significantly accelerated turnover of added maize carbon. Changes in substrate quantity and quality in the course of the decomposition appeared to have less influence on the microbial community composition and its substrate utilization than the prevailing environmental/site conditions, to which the microbial community adapted quickly upon change. In general, microbial community composition and function significantly affected substrate decomposition rates only in the later stage of decomposition when the differentiation in substrate use among the microbial groups became more evident. Our study demonstrated that rising temperatures in alpine ecosystems may accelerate decomposition of litter carbon and also lead to a rapid adaptation of the microbial communities to the new environmental conditions. PMID:22809312

  13. Climate impact of beef: an analysis considering multiple time scales and production methods without use of global warming potentials

    NASA Astrophysics Data System (ADS)

    Pierrehumbert, R. T.; Eshel, G.

    2015-08-01

    An analysis of the climate impact of various forms of beef production is carried out, with a particular eye to the comparison between systems relying primarily on grasses grown in pasture (‘grass-fed’ or ‘pastured’ beef) and systems involving substantial use of manufactured feed requiring significant external inputs in the form of synthetic fertilizer and mechanized agriculture (‘feedlot’ beef). The climate impact is evaluated without employing metrics such as {{CO}}2{{e}} or global warming potentials. The analysis evaluates the impact at all time scales out to 1000 years. It is concluded that certain forms of pastured beef production have substantially lower climate impact than feedlot systems. However, pastured systems that require significant synthetic fertilization, inputs from supplemental feed, or deforestation to create pasture, have substantially greater climate impact at all time scales than the feedlot and dairy-associated systems analyzed. Even the best pastured system analyzed has enough climate impact to justify efforts to limit future growth of beef production, which in any event would be necessary if climate and other ecological concerns were met by a transition to primarily pasture-based systems. Alternate mitigation options are discussed, but barring unforseen technological breakthroughs worldwide consumption at current North American per capita rates appears incompatible with a 2 °C warming target.

  14. Potential increase of flood hazards in Korea due to global warming from a high-resolution regional climate simulation

    NASA Astrophysics Data System (ADS)

    Im, Eun-Soon; Lee, Byong-Ju; Kwon, Ji-Hye; in, So-Ra; Han, Sang-Ok

    2012-02-01

    Because of the importance of the changes in the hydrologic cycle, accurate assessment of precipitation characteristics is essential to understand the impact of climate change due to global warming. This study investigates the changes in extreme precipitation with sub-daily and daily temporal scales. For a fine-scale climate change projection focusing on the Korean peninsula (20 km), we performed the dynamical downscaling of the global climate scenario covering the period 1971-2100 (130-year) simulated by the Max-Planck-Institute global climate model, ECHAM5, using the latest version of the International Centre for Theoretical Physics (ICTP) regional climate model, RegCM3. While annual mean precipitation exhibits a pronounced interannual and interdecadal variability, with the increasing or decreasing trend repeated during a certain period, extreme precipitation with sub-daily and daily temporal scales estimated from the generalized extreme value distribution shows consistently increasing pattern. The return period of extreme precipitation is significantly reduced despite the decreased annual mean precipitation at the end of 21st century. The decreased relatively weak precipitation is responsible for the decreased total precipitation, so that the decreased total precipitation does not necessarily mean less heavy precipitation. Climate change projection based on the ECHAM5-RegCM3 model chain clearly shows the effect of global warming in increasing the intensity and frequency of extreme precipitation, even without significantly increased total precipitation, which implies an increased risk for flood hazards.

  15. Impact of warming climate and cultivar change on maize phenology in the last three decades in North China Plain

    NASA Astrophysics Data System (ADS)

    Xiao, Dengpan; Qi, Yongqing; Shen, Yanjun; Tao, Fulu; Moiwo, Juana P.; Liu, Jianfeng; Wang, Rede; Zhang, He; Liu, Fengshan

    2015-04-01

    As climate change could significantly influence crop phenology and subsequent crop yield, adaptation is a critical mitigation process of the vulnerability of crop growth and production to climate change. Thus, to ensure crop production and food security, there is the need for research on the natural (shifts in crop growth periods) and artificial (shifts in crop cultivars) modes of crop adaptation to climate change. In this study, field observations in 18 stations in North China Plain (NCP) are used in combination with Agricultural Production Systems Simulator (APSIM)-Maize model to analyze the trends in summer maize phenology in relation to climate change and cultivar shift in 1981-2008. Apparent warming in most of the investigated stations causes early flowering and maturity and consequently shortens reproductive growth stage. However, APSIM-Maize model run for four representative stations suggests that cultivar shift delays maturity and thereby prolongs reproductive growth (flowering to maturity) stage by 2.4-3.7 day per decade (d 10a-1). The study suggests a gradual adaptation of maize production process to ongoing climate change in NCP via shifts in high thermal cultivars and phenological processes. It is concluded that cultivation of maize cultivars with longer growth periods and higher thermal requirements could mitigate the negative effects of warming climate on crop production and food security in the NCP study area and beyond.

  16. Barrier layers of the Atlantic warm pool: Formation mechanism and influence on weather and climate

    NASA Astrophysics Data System (ADS)

    Balaguru, Karthik

    The aim of this research is to study the formation mechanism of Barrier Layers (BL) in the western tropical Atlantic and their influence on the tropical Atlantic climate at both short and long timescales. Many Coupled General Circulation Models (CGCMs) tend to overestimate the salinity in the Atlantic warm pool or the Northwestern Tropical Atlantic (NWTA) and underestimate the surface salinity in the subtropical salinity maxima region. Most of these models also suffer from a sea-surface temperature (SST) bias in the NWTA region, leading to suggestions that the upper ocean salinity stratification may need to be improved in order to improve the BL simulations and thus the SST through BL-SST-Intertropical Convergence Zone (ITCZ) feedbacks. We used a CGCM to perform a set of idealized numerical experiments to understand the sensitivity of the BL and consequently SST in the NWTA region to freshwater flux and hence the upper ocean salinity stratification. We find that the BL of the western tropical Atlantic is quite sensitive to upper ocean salinity changes in the Amazon River discharge region and the subtropical salinity maxima region. The BL phenomenon is further manifested by the formation of winter temperature inversions in our model simulations. However, in the region of improved BL simulation, the SST response is not statistically significant. SST response to Tropical Cyclones (TCs) is studied for the Atlantic region using a high-resolution coupled regional climate model (CRCM) and observational data sets. The presence of a BL, defined as the layer below the mixed layer that separates the base of the isothermal layer from the base of the isohaline layer, is found to modulate the SST response. The amplitude of TC-induced surface cooling is reduced by more than 35% in the presence of a BL, as a consequence of the weak thermal stratification. Furthermore, in locations when the BL exhibits a temperature inversion, TC-induced mixing can result in weak surface warming. BLs considerably reduce the rightward bias for tropical storms, but the effect is less conspicuous for TCs. The enthalpy flux into the atmosphere at the air-sea interface is enhanced by 16 % and the increase in upper ocean potential energy due to TC-induced mixing is reduced by 25 % in the presence of BLs. The results from the coupled model are supported by an observational analysis performed using re-analysis data sets, as well as data from Argo floats and TRMM satellite. As previous modeling and observational studies have indicated that the surface cooling caused by TC-induced mixing acts as a negative feedback for its intensity, results from our study suggest that BLs may have potential implications for TC intensity prediction.

  17. Effects of airflow on body temperatures and sleep stages in a warm humid climate

    NASA Astrophysics Data System (ADS)

    Tsuzuki, Kazuyo; Okamoto-Mizuno, Kazue; Mizuno, Koh; Iwaki, Tatsuya

    2008-03-01

    Airflow is an effective way to increase heat loss—an ongoing process during sleep and wakefulness in daily life. However, it is unclear whether airflow stimulates cutaneous sensation and disturbs sleep or reduces the heat load and facilitates sleep. In this study, 17 male subjects wearing short pyjamas slept on a bed with a cotton blanket under two of the following conditions: (1) air temperature (Ta) 26°C, relative humidity (RH) 50%, and air velocity (V) 0.2 m s-1; (2) Ta 32°C, RH 80%, V 1.7 m s-1; (3) Ta 32°C; RH 80%, V 0.2 m s-1 (hereafter referred to as 26/50, 32/80 with airflow, and 32/80 with still air, respectively). Electroencephalograms, electrooculograms, and mental electromyograms were obtained for all subjects. Rectal (Tre) and skin (Ts) temperatures were recorded continuously during the sleep session, and body-mass was measured before and after the sleep session. No significant differences were observed in the duration of sleep stages between subjects under the 26/50 and 32/80 with airflow conditions; however, the total duration of wakefulness decreased significantly in subjects under the 32/80 with airflow condition compared to that in subjects under the 32/80 with still air condition ( P < 0.05). Tre, Tsk, Ts, and body-mass loss under the 32/80 with airflow condition were significantly higher compared to those under the 26/50 condition, and significantly lower than those under the 32/80 with still air condition ( P < 0.05). An alleviated heat load due to increased airflow was considered to exist between the 32/80 with still air and the 26/50 conditions. Airflow reduces the duration of wakefulness by decreasing Tre, Tsk, Ts, and body-mass loss in a warm humid condition.

  18. Reef fish dynamic response to climatic variability in a warm eastern Mediterranean semi-enclosed basin

    NASA Astrophysics Data System (ADS)

    Agiadi, K.; Koskeridou, E.; Giamali, Ch.; Karakitsios, V.

    2012-04-01

    Recent studies on the effects of global warming on fish populations reveal that the resulting hypoxia-based habitat compression due to the expansion of the oxygen minimum zone may lead to the restriction of fish depth distributions to the oxygenated near-surface layer1. Here we postulate that similar phenomena may have affected the fish distribution in the early Pliocene Heraklion semi-enclosed sea (Crete, eastern Mediterranean). Fish otoliths from Voutes section are systematically identified and the data is examined from a palaeoecologic perspective in response to the Pliocene climatic variability. Bregmaceros and Diaphus taaningi otoliths' relative abundances are used as reliable palaeoclimatic indicators2. The Voutes section sediments contain a very rich fish fauna. Diaphus spp., Bregmaceros sp., Sardinella maderensis, Phosichthyidae and Sternoptychyidae form the pelagic component. Mesopelagic taxa belong mostly to Myctophids. The benthopelagic and benthic component of the fish fauna is very well diversified and is comprised of Gobiids, such as Gobius cf. niger, Callogobius sp., Lesueurigobius aff. sanzoi, and Aphya sp., as well as Gadiculus labiatus, Laemonema sp., Oblada melanura, Parascombrus mutinensis, Barbourisia rufa, Blennius sp., Ammodytes sp., Solea aff. solea. The presence of Oligopus sp., Spratelloides sp., and Brotula cf. mutlibarbata in the middle part of the section indicate the development of a reef in the study area. The palaeoecologic analysis of the surface, intermediate and deep water faunal groups indicate that the pelagic fish populations in the semi-enclosed early Pliocene Heraklion basin directly reflect the climatic variability. However, the intermediate and deep water fish did not respond to climate change in the same manner. Indeed, two dysoxic events are recorded in this section, where the pelagic component of the fauna is almost exclusively comprised of Bregmaceros sp., few Myctophids are present, and the benthic and benthopelagic taxa are nearly non-existent. These events are intermitted by the development of a reef system near the study area, marked by the intense diversification of the fish fauna on all water levels. The mollusc fauna turnover reinforces the above results. Conclusively, the present study clearly presents the fish populations' dynamic characteristics of in response to climatic variability. Acknowledgments This research has been co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: Heracleitus II. Investing in knowledge society through the European Social Fund.

  19. Error analysis of FLC experimental data at warm/hot stamping conditions

    NASA Astrophysics Data System (ADS)

    Zhuang, Weimin; Zhang, Mengxi; Chen, Yanhong

    2014-07-01

    Forming limit curves(FLCs) are commonly used for evaluating the formability of sheet metals. However, it is difficult to obtain the FLCs with desirable accuracy by experiments due to that the friction effects are non-negligible under warm/hot stamping conditions. To investigate the experimental errors, experiments for obtaining the FLCs of the AA5754 are conducted at 250°C. Then, FE models are created and validated on the basis of experimental results. A number of FE simulations are carried out for FLC test-pieces and punches with different geometry configurations and varying friction coefficients between the test-piece and the punch. The errors for all the test conditions are predicted and analyzed. Particular attention of error analysis is paid to two special cases, namely, the biaxial FLC test and the uniaxial FLC test. The failure location and the variation of the error with respect to the friction coefficient are studied as well. The results obtained from the FLC tests and the above analyses show that, for the biaxial tension state, the friction coefficient should be controlled within 0.15 to avoid significant shifting of the necking location away from the center of the punch; for the uniaxial tension state, the friction coefficient should be controlled within 0.1 to guarantee the validity of the data collected from FLC tests. The conclusions summarized are beneficial for obtaining accurate FLCs under warm/hot stamping conditions.

  20. Modeling the effects of fire severity and climate warming on active layer and soil carbon dynamics of black spruce forests across the landscape in interior Alaska

    USGS Publications Warehouse

    Genet, H.; McGuire, Anthony David; Barrett, K.; Breen, A.; Euskirchen, E.S.; Johnstone, J.F.; Kasischke, E.S.; Melvin, A.M.; Bennett, A.; Mack, M.C.; Rupp, T.S.; Schuur, A.E.G.; Turetsky, M.R.; Yuan, F.

    2013-01-01

    There is a substantial amount of carbon stored in the permafrost soils of boreal forest ecosystems, where it is currently protected from decomposition. The surface organic horizons insulate the deeper soil from variations in atmospheric temperature. The removal of these insulating horizons through consumption by fire increases the vulnerability of permafrost to thaw, and the carbon stored in permafrost to decomposition. In this study we ask how warming and fire regime may influence spatial and temporal changes in active layer and carbon dynamics across a boreal forest landscape in interior Alaska. To address this question, we (1) developed and tested a predictive model of the effect of fire severity on soil organic horizons that depends on landscape-level conditions and (2) used this model to evaluate the long-term consequences of warming and changes in fire regime on active layer and soil carbon dynamics of black spruce forests across interior Alaska. The predictive model of fire severity, designed from the analysis of field observations, reproduces the effect of local topography (landform category, the slope angle and aspect and flow accumulation), weather conditions (drought index, soil moisture) and fire characteristics (day of year and size of the fire) on the reduction of the organic layer caused by fire. The integration of the fire severity model into an ecosystem process-based model allowed us to document the relative importance and interactions among local topography, fire regime and climate warming on active layer and soil carbon dynamics. Lowlands were more resistant to severe fires and climate warming, showing smaller increases in active layer thickness and soil carbon loss compared to drier flat uplands and slopes. In simulations that included the effects of both warming and fire at the regional scale, fire was primarily responsible for a reduction in organic layer thickness of 0.06 m on average by 2100 that led to an increase in active layer thickness of 1.1 m on average by 2100. The combination of warming and fire led to a simulated cumulative loss of 9.6 kgC m?2 on average by 2100. Our analysis suggests that ecosystem carbon storage in boreal forests in interior Alaska is particularly vulnerable, primarily due to the combustion of organic layer thickness in fire and the related increase in active layer thickness that exposes previously protected permafrost soil carbon to decomposition.

  1. Modeling the effects of fire severity and climate warming on active layer thickness and soil carbon storage of black spruce forests across the landscape in interior Alaska

    SciTech Connect

    Genet, Helene; McGuire, A. David; Barrett, K.; Breen, Amy; Euskirchen, Eugenie S; Johnstone, J. F.; Kasischke, Eric S.; Melvin, A. M.; Bennett, A.; Mack, M. C.; Rupp, Scott T.; Schuur, Edward; Turetsky, M. R.; Yuan, Fengming

    2013-01-01

    There is a substantial amount of carbon stored in the permafrost soils of boreal forest ecosystems, where it is currently protected from decomposition. The surface organic horizons insulate the deeper soil from variations in atmospheric temperature. The removal of these insulating horizons through consumption by fire increases the vulnerability of permafrost to thaw, and the carbon stored in permafrost to decomposition. In this study we ask how warming and fire regime may influence spatial and temporal changes in active layer and carbon dynamics across a boreal forest landscape in interior Alaska. To address this question, we (1) developed and tested a predictive model of the effect of fire severity on soil organic horizons that depends on landscape-level conditions and (2) used this model to evaluate the long-term consequences of warming and changes in fire regime on active layer and soil carbon dynamics of black spruce forests across interior Alaska. The predictive model of fire severity, designed from the analysis of field observations, reproduces the effect of local topography (landform category, the slope angle and aspect and flow accumulation), weather conditions (drought index, soil moisture) and fire characteristics (day of year and size of the fire) on the reduction of the organic layercaused by fire. The integration of the fire severity model into an ecosystem process-based model allowed us to document the relative importance and interactions among local topography, fire regime and climate warming on active layer and soil carbon dynamics. Lowlands were more resistant to severe fires and climate warming, showing smaller increases in active layer thickness and soil carbon loss compared to drier flat uplands and slopes. In simulations that included the effects of both warming and fire at the regional scale, fire was primarily responsible for a reduction in organic layer thickness of 0.06 m on average by 2100 that led to an increase in active layer thickness of 1.1 m on average by 2100. The combination of warming and fire led to a simulated cumulative loss of 9.6 kgC m 2 on average by 2100. Our analysis suggests that ecosystem carbon storage in boreal forests in interior Alaska is particularly vulnerable, primarily due to the combustion of organic layer thickness in fire and the related increase in active layer thickness that exposes previously protected permafrost soil carbon to decomposition.

  2. Diagnosis of the summertime warm and dry bias over the U. S. Southern Great Plains in the GFDL climate model using a weather forecasting approach

    SciTech Connect

    Klein, S A; Jiang, X; Boyle, J; Malyshev, S; Xie, S

    2006-07-11

    Weather forecasts started from realistic initial conditions are used to diagnose the large warm and dry bias over the United States Southern Great Plains simulated by the GFDL climate model. The forecasts exhibit biases in surface air temperature and precipitation within 3 days which appear to be similar to the climate bias. With the model simulating realistic evaporation but underestimated precipitation, a deficit in soil moisture results which amplifies the initial temperature bias through feedbacks with the land surface. The underestimate of precipitation is associated with an inability of the model to simulate the eastward propagation of convection from the front-range of the Rocky Mountains and is insensitive to an increase of horizontal resolution from 2{sup o} to 0.5{sup o} latitude.

  3. Aerosol-Induced Changes of Convective Cloud Anvils Produce Strong Climate Warming

    NASA Technical Reports Server (NTRS)

    Koren, I.; Remer, L. A.; Altaratz, O.; Martins, J. V.; Davidi, A.

    2010-01-01

    The effect of aerosol on clouds poses one of the largest uncertainties in estimating the anthropogenic contribution to climate change. Small human-induced perturbations to cloud characteristics via aerosol pathways can create a change in the top-of-atmosphere radiative forcing of hundreds of Wm(exp-2) . Here we focus on links between aerosol and deep convective clouds of the Atlantic and Pacific Intertropical Convergence Zones, noting that the aerosol environment in each region is entirely different. The tops of these vertically developed clouds consisting of mostly ice can reach high levels of the atmosphere, overshooting the lower stratosphere and reaching altitudes greater than 16 km. We show a link between aerosol, clouds and the free atmosphere wind profile that can change the magnitude and sign of the overall climate radiative forcing. We find that increased aerosol loading is associated with taller cloud towers and anvils. The taller clouds reach levels of enhanced wind speeds that act to spread and thin the anvi1 clouds, increasing areal coverage and decreasing cloud optical depth. The radiative effect of this transition is to create a positive radiative forcing (warming) at top-of-atmosphere. Furthermore we introduce the cloud optical depth (r), cloud height (Z) forcing space and show that underestimation of radiative forcing is likely to occur in cases of non homogenous clouds. Specifically, the mean radiative forcing of towers and anvils in the same scene can be several times greater than simply calculating the forcing from the mean cloud optical depth in the scene. Limitations of the method are discussed, alternative sources of aerosol loading are tested and meteorological variance is restricted, but the trend of taller clouds; increased and thinner anvils associated with increased aerosol loading remains robust through all the different tests and perturbations.

  4. Sensitivity of tropical intraseasonal variability to the pattern of climate warming

    E-print Network

    Xie, Shang-Ping

    of this warming perturbation that have the same global mean SST change are the other two. Changes in intraseasonal, and significant increases in MJO precipitation amplitude for a globally uniform warming. The amplitude of the wind historical MJO activity to develop a statistical stochastic model based on west Pacific and Indian Ocean warm

  5. HEAT STRESS CLIMATIC CONDITIONS AND THE PHYSIOLOGICAL RESPONSES OF CATTLE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle are adaptable to a wide range of climatic conditions, but can be severely challenged by sudden heat waves. Repeated hot, humid environments, with little air flow or cloud cover, are periods of concern, especially if conditions persist over a three-day period without significant nighttime reli...

  6. High performance solutions and data for nZEBs offices located in warm climates

    PubMed Central

    Congedo, Paolo Maria; Baglivo, Cristina; Zacà, Ilaria; D?Agostino, Delia

    2015-01-01

    This data article contains eleven tables supporting the research article entitled: Cost-Optimal Design For Nearly Zero Energy Office Buildings Located In Warm Climates [1]. The data explain the procedure of minimum energy performance requirements presented by the European Directive (EPBD) [2] to establish several variants of energy efficiency measures with the integration of renewable energy sources in order to reach nZEBs (nearly zero energy buildings) by 2020. This files include the application of comparative methodological framework and give the cost-optimal solutions for non-residential building located in Southern Italy. The data describe office sector in which direct the current European policies and investments [3], [4]. In particular, the localization of the building, geometrical features, thermal properties of the envelope and technical systems for HVAC are reported in the first sections. Energy efficiency measures related to orientation, walls, windows, heating, cooling, dhw and RES are given in the second part of the group; this data article provides 256 combinations for a financial and macroeconomic analysis. PMID:26629494

  7. Is the Climate of Bering Sea Warming and Affecting the Ecosystem?

    NASA Astrophysics Data System (ADS)

    Overland, James E.; Stabeno, Phyllis J.

    2004-08-01

    Observations from the Bering Sea are good indicators of decadal shifts in climate, as the Bering is a transition region between the cold, dry Arctic air mass to the north, and the moist, relatively warm maritime air mass to the south. The Bering Sea is also a transition region between Arctic and sub-Arctic ecosystems; this boundary can be loosely identified with the extent of winter sea-ice cover. Like a similar transition zone in the eastern North Atlantic, the Bering Sea is experiencing a northward biogeographical shift in response to changing temperature and atmospheric forcing. If this shift continues over the next decade, it will have major impacts on commercial and subsistence harvests as Arctic species are displaced by sub-Arctic species. The stakes are enormous, as this rich and diverse ecosystem currently provides 47% of the U.S. fishery production by weight, and is home to 80% of the U.S. sea bird population, 95% of northern fur seals, and major populations of Steller sea lions, walrus, and whales.

  8. Predicting organismal vulnerability to climate warming: roles of behaviour, physiology and adaptation

    PubMed Central

    Huey, Raymond B.; Kearney, Michael R.; Krockenberger, Andrew; Holtum, Joseph A. M.; Jess, Mellissa; Williams, Stephen E.

    2012-01-01

    A recently developed integrative framework proposes that the vulnerability of a species to environmental change depends on the species' exposure and sensitivity to environmental change, its resilience to perturbations and its potential to adapt to change. These vulnerability criteria require behavioural, physiological and genetic data. With this information in hand, biologists can predict organisms most at risk from environmental change. Biologists and managers can then target organisms and habitats most at risk. Unfortunately, the required data (e.g. optimal physiological temperatures) are rarely available. Here, we evaluate the reliability of potential proxies (e.g. critical temperatures) that are often available for some groups. Several proxies for ectotherms are promising, but analogous ones for endotherms are lacking. We also develop a simple graphical model of how behavioural thermoregulation, acclimation and adaptation may interact to influence vulnerability over time. After considering this model together with the proxies available for physiological sensitivity to climate change, we conclude that ectotherms sharing vulnerability traits seem concentrated in lowland tropical forests. Their vulnerability may be exacerbated by negative biotic interactions. Whether tropical forest (or other) species can adapt to warming environments is unclear, as genetic and selective data are scant. Nevertheless, the prospects for tropical forest ectotherms appear grim. PMID:22566674

  9. Climate warming shifts carbon allocation from stemwood to roots in calcium-depleted spruce forests

    USGS Publications Warehouse

    Lapenis, Andrei Gennady; Lawrence, Gregory B.; Heim, Alexander; Zheng, Chengyang; Shortle, Walter

    2013-01-01

    Increased greening of northern forests, measured by the Normalized Difference Vegetation Index (NDVI), has been presented as evidence that a warmer climate has increased both net primary productivity (NPP) and the carbon sink in boreal forests. However, higher production and greener canopies may accompany changes in carbon allocation that favor foliage or fine roots over less decomposable woody biomass. Furthermore, tree core data throughout mid- and northern latitudes have revealed a divergence problem (DP), a weakening in tree ring responses to warming over the past half century that is receiving increasing attention, but remains poorly understood. Often, the same sites exhibit trend inconsistency phenomenon (TIP), namely positive, or no trends in growing season NDVI where negative trends in tree ring indexes are observed. Here we studied growth of two Norway spruce (Picea abies) stands in western Russia that exhibited both the DP and TIP but were subject to soil acidification and calcium depletion of differing timing and severity. Our results link the decline in radial growth starting in 1980 to a shift in carbon allocation from wood to roots driven by a combination of two factors: (a) soil acidification that depleted calcium and impaired root function and (b) earlier onset of the growing season that further taxed the root system. The latter change in phenology appears to act as a trigger at both sites to push trees into nutrient limitation as the demand for Ca increased with the longer growing season, thereby causing the shift in carbon allocation.

  10. Climate warming shifts carbon allocation from stemwood to roots in calcium-depleted spruce forests

    NASA Astrophysics Data System (ADS)

    Lapenis, Andrei; Lawrence, Gregory; Buyantuev, Alexander

    2015-04-01

    Increased greening of northern forests, measured by the Normalized Difference Vegetation Index (NDVI), has been presented as evidence that a warmer climate has increased both net primary productivity (NPP) and the carbon sink in boreal forests. However, higher production and greener canopies may accompany changes in carbon allocation that favor foliage or fine roots over less decomposable woody biomass. Furthermore, tree core data throughout mid- and northern latitudes have revealed a divergence problem (DP), a weakening in tree ring responses to warming over the past half century that is receiving increasing attention, but remains poorly understood. Often, the same sites exhibit trend inconsistency phenomenon (TIP), namely positive, or no trends in growing season NDVI where negative trends in tree ring indexes are observed. Here we studied growth of two Norway spruce (Picea abies) stands in western Russia that exhibited both the DP and TIP but were subject to soil acidification and calcium depletion of differing timing and severity. Our results link the decline in radial growth starting in 1980 to a shift in carbon allocation from wood to roots driven by a combination of two factors: (a) soil acidification that depleted calcium and impaired root function and (b) earlier onset of the growing season that further taxed the root system. The latter change in phenology appears to act as a trigger at both sites to push trees into nutrient limitation as the demand for Ca increased with the longer growing season, thereby causing the shift in carbon allocation.

  11. Energy and global warming impacts of next generation refrigeration and air conditioning technologies

    SciTech Connect

    Sand, J.R.; Fischer, S.K.; Baxter, V.D.

    1996-10-01

    Significant developments have occurred in hydrofluorocarbon (HFC) and the application of ammonia and hydrocarbons as refrigerant working fluids since the original TEWI (Total Equivalent Warming Impact) report in 1991. System operating and performance data on alternative refrigerants and refrigeration technologies justify and updated evaluation of these new alternative refrigerants and competing technologies in well-characterized applications. Analytical and experimental results are used to show quantitative comparisons between HFCS, HFC blends, hydrocarbons, and ammonia, used as refrigerants. An objective evaluation is presented for commercial and near commercial non-CFC refrigerants/blowing agents and alternative refrigeration technologies. This information is needed for objective and quantitative decisions on policies addressing greenhouse gas emissions from refrigeration and air conditioning equipment. The evaluation assesses the energy use and global warming impacts of refrigeration and air conditioning technologies that could be commercialized during the phase out of HCFCS. Quantitative comparison TEWI for two application areas are presented. Opportunities for significant reductions in TEWI are seen with currently known refrigerants through improved maintenance and servicing practices and improved product designs.

  12. Genotypic trait variation modifies effects of climate warming and nitrogen deposition on litter mass loss and microbial respiration.

    PubMed

    Hines, Jes; Reyes, Marta; Mozder, Thomas J; Gessner, Mark O

    2014-12-01

    Intraspecific variation in genotypically determined traits can influence ecosystem processes. Therefore, the impact of climate change on ecosystems may depend, in part, on the distribution of plant genotypes. Here we experimentally assess effects of climate warming and excess nitrogen supply on litter decomposition using 12 genotypes of a cosmopolitan foundation species collected across a 2100 km latitudinal gradient and grown in a common garden. Genotypically determined litter-chemistry traits varied substantially within and among geographic regions, which strongly affected decomposition and the magnitude of warming effects, as warming accelerated litter mass loss of high-nutrient, but not low-nutrient, genotypes. Although increased nitrogen supply alone had no effect on decomposition, it strongly accelerated litter mass loss of all genotypes when combined with warming. Rates of microbial respiration associated with the leaf litter showed nearly identical responses as litter mass loss. These results highlight the importance of interactive effects of environmental factors and suggest that loss or gain of genetic variation associated with key phenotypic traits can buffer, or exacerbate, the impact of global change on ecosystem process rates in the future. PMID:25099691

  13. Climate warming increases biodiversity of small rodents by favoring rare or less abundant species in a grassland ecosystem.

    PubMed

    Jiang, Guangshun; Liu, Jun; Xu, Lei; Yu, Guirui; He, Honglin; Zhang, Zhibin

    2013-06-01

    Our Earth is facing the challenge of accelerating climate change, which imposes a great threat to biodiversity. Many published studies suggest that climate warming may cause a dramatic decline in biodiversity, especially in colder and drier regions. In this study, we investigated the effects of temperature, precipitation and a normalized difference vegetation index on biodiversity indices of rodent communities in the current or previous year for both detrended and nondetrended data in semi-arid grassland of Inner Mongolia during 1982-2006. Our results demonstrate that temperature showed predominantly positive effects on the biodiversity of small rodents; precipitation showed both positive and negative effects; a normalized difference vegetation index showed positive effects; and cross-correlation function values between rodent abundance and temperature were negatively correlated with rodent abundance. Our results suggest that recent climate warming increased the biodiversity of small rodents by providing more benefits to population growth of rare or less abundant species than that of more abundant species in Inner Mongolia grassland, which does not support the popular view that global warming would decrease biodiversity in colder and drier regions. We hypothesized that higher temperatures might benefit rare or less abundant species (with smaller populations and more folivorous diets) by reducing the probability of local extinction and/or by increasing herbaceous food resources. PMID:23731812

  14. Fungal Diversity in Permafrost and Tallgrass Prairie Soils under Experimental Warming Conditions

    PubMed Central

    StLouis, Derek; Cole, James R.; Luo, Yiqi; Wu, Liyou; Schuur, E. A. G; Zhou, Jizhong; Tiedje, James M.

    2013-01-01

    Soil fungi play a major role in terrestrial ecosystem functioning through interactions with soil structure, plants, micro- and mesofauna, and nutrient cycling through predation, pathogenesis, mutualistic, and saprotrophic roles. The diversity of soil fungi was assessed by sequencing their 28S rRNA gene in Alaskan permafrost and Oklahoma tallgrass prairie soils at experimental sites where the effect of climate warming is under investigation. A total of 226,695 reads were classified into 1,063 genera, covering 62% of the reference data set. Using the Bayesian Classifier offered by the Ribosomal Database Project (RDP) with 50% bootstrapping classification confidence, approximately 70% of sequences were returned as “unclassified” at the genus level, although the majority (?65%) were classified at the class level, which provided insight into these lesser-known fungal lineages. Those unclassified at the genus level were subjected to BLAST analysis against the ARB-SILVA database, where ?50% most closely matched nonfungal taxa. Compared to the more abundant sequences, a higher proportion of rare operational taxonomic units (OTU) were successfully classified to genera at 50% bootstrap confidence, indicating that the fungal rare biosphere in these sites is not composed of sequencing artifacts. There was no significant effect after 1 year of warming on the fungal community structure at both sites, except perhaps for a few minor members, but there was a significant effect of sample depth in the permafrost soils. Despite overall significant community structure differences driven by variations in OTU dominance, the prairie and permafrost soils shared 90% and 63% of all fungal sequences, respectively, indicating a fungal “seed bank” common between both sites. PMID:24014534

  15. Innovative Air Conditioning and Climate Control

    NASA Technical Reports Server (NTRS)

    Graf, John

    2015-01-01

    NASA needed to develop a desiccant wheel based humidity removal system to enable the long term testing of the Orion CO2 scrubber on the International Space Station. In the course of developing that system, we learned three things that are relevant to energy efficient air conditioning of office towers. NASA developed a conceptual design for a humidity removal system for an office tower environment. We are looking for interested partners to prototype and field test this concept.

  16. Simulating Freshwater Availability under Future Climate Conditions

    NASA Astrophysics Data System (ADS)

    Zhao, F.; Zeng, N.; Motesharrei, S.; Gustafson, K. C.; Rivas, J.; Miralles-Wilhelm, F.; Kalnay, E.

    2013-12-01

    Freshwater availability is a key factor for regional development. Precipitation, evaporation, river inflow and outflow are the major terms in the estimate of regional water supply. In this study, we aim to obtain a realistic estimate for these variables from 1901 to 2100. First we calculated the ensemble mean precipitation using the 2011-2100 RCP4.5 output (re-sampled to half-degree spatial resolution) from 16 General Circulation Models (GCMs) participating the Coupled Model Intercomparison Project Phase 5 (CMIP5). The projections are then combined with the half-degree 1901-2010 Climate Research Unit (CRU) TS3.2 dataset after bias correction. We then used the combined data to drive our UMD Earth System Model (ESM), in order to generate evaporation and runoff. We also developed a River-Routing Scheme based on the idea of Taikan Oki, as part of the ESM. It is capable of calculating river inflow and outflow for any region, driven by the gridded runoff output. River direction and slope information from Global Dominant River Tracing (DRT) dataset are included in our scheme. The effects of reservoirs/dams are parameterized based on a few simple factors such as soil moisture, population density and geographic regions. Simulated river flow is validated with river gauge measurements for the world's major rivers. We have applied our river flow calculation to two data-rich watersheds in the United States: Phoenix AMA watershed and the Potomac River Basin. The results are used in our SImple WAter model (SIWA) to explore water management options.

  17. J5.14 SIMULATION OF POSSIBLE FUTURE EFFECTS OF GREENHOUSE WARMING ON GREAT LAKES WATER SUPPLY USING A REGIONAL CLIMATE MODEL

    E-print Network

    of greenhouse warming on the water resources of the Great Lakes Basin. Public attention has been focused climate was simulated over the Great Lakes Basin for time periods centered at 1989, 2030, and 2095J5.14 SIMULATION OF POSSIBLE FUTURE EFFECTS OF GREENHOUSE WARMING ON GREAT LAKES WATER SUPPLY USING

  18. Climate condition in the Central Europe during the Weichselian Ice Sheet according to the Educational Global Climate Modeling Project

    NASA Astrophysics Data System (ADS)

    Szuman, Izabela; Czernecki, Bartosz

    2010-05-01

    The expansion and retreat of the ice sheet is controlled by climate changes, and from the other hand, a huge ice mass influences on the climate in the regional scale. This mechanism is commonly known as the fact but often without making reconstruction by using climatological modeling. The purpose of our study is to reconstruct the climate condition during the Weichselian Ice Sheet in the Central Europe, especially for Poland and surrounded countries. The Global Climate Model (GCM) is made for predicting climate, but simplified version can be useful for reconstructing paleoclimate. Hence, the simple initial conditions and surface data proposed by the Educational version of the GCM was applied. In our study we used a simplified version of the GCM to calculate main climate characteristics within the time limits c. 21 000 BP - 18 000 BP, which has been previously invented on Columbia University. The model is constructed on grid with a horizontal resolution 8° latitude by 10° longitude and was establish for modeling most of weather conditions based on available paleoclimate data. It is possible to estimate the probable climate condition along the southern ice sheets margin on the basis of output from the GCM and GIS modeling techniques. Above the ice mass occurs local high pressure area, which seriously interfered on atmospheric circulation. Whereas the low pressure systems in the southern part of continent may caused permanent barometric situation, which stimulates wind directions as well as the precipitable water available in the mass of air. The climate on the east-south border of ice margin was colder and drier than on the west-south region, where it was more ocean-reliable and gentle with higher temperatures. The differences in temperature between the western and eastern part of the Central Europe reached few centigrade. Against a background of the mean paleoclimatic situation in the Central Europe there is coming out a question about the particular paleoclimate condition in Poland. In this area occurred a huge ice-lobe, distinct in the geomorphology, during the Weichselian Ice Sheet. Authors try to define the role of such a big ice-barrier on the climate changes at the foreland, between the western and eastern side. It is necessary to consider the ice cap thickness in the lobe estimated from separately prepared in GIS software (GRASS) 3D ice-sheet surface elevation model, together with the climatic data from the GCM for regional situation. The results of modeling are also related to available abiotic parameters for Poland. Finally, it is suggested that the ice-lobe was high enough barrier to cause the differences in temperature distribution due to limitation of delivery the warm Atlantic air masses to the eastern region. It has also significant impact on local wind field, especially in transition areas.

  19. Protected Area Tourism in a Changing Climate: Will Visitation at US National Parks Warm Up or Overheat?

    PubMed Central

    Fisichelli, Nicholas A.; Schuurman, Gregor W.; Monahan, William B.; Ziesler, Pamela S.

    2015-01-01

    Climate change will affect not only natural and cultural resources within protected areas but also tourism and visitation patterns. The U.S. National Park Service systematically collects data regarding its 270+ million annual recreation visits, and therefore provides an opportunity to examine how human visitation may respond to climate change from the tropics to the polar regions. To assess the relationship between climate and park visitation, we evaluated historical monthly mean air temperature and visitation data (1979–2013) at 340 parks and projected potential future visitation (2041–2060) based on two warming-climate scenarios and two visitation-growth scenarios. For the entire park system a third-order polynomial temperature model explained 69% of the variation in historical visitation trends. Visitation generally increased with increasing average monthly temperature, but decreased strongly with temperatures > 25°C. Linear to polynomial monthly temperature models also explained historical visitation at individual parks (R2 0.12-0.99, mean = 0.79, median = 0.87). Future visitation at almost all parks (95%) may change based on historical temperature, historical visitation, and future temperature projections. Warming-mediated increases in potential visitation are projected for most months in most parks (67–77% of months; range across future scenarios), resulting in future increases in total annual visits across the park system (8–23%) and expansion of the visitation season at individual parks (13–31 days). Although very warm months at some parks may see decreases in future visitation, this potential change represents a relatively small proportion of visitation across the national park system. A changing climate is likely to have cascading and complex effects on protected area visitation, management, and local economies. Results suggest that protected areas and neighboring communities that develop adaptation strategies for these changes may be able to both capitalize on opportunities and minimize detriment related to changing visitation. PMID:26083361

  20. Protected Area Tourism in a Changing Climate: Will Visitation at US National Parks Warm Up or Overheat?

    PubMed

    Fisichelli, Nicholas A; Schuurman, Gregor W; Monahan, William B; Ziesler, Pamela S

    2015-01-01

    Climate change will affect not only natural and cultural resources within protected areas but also tourism and visitation patterns. The U.S. National Park Service systematically collects data regarding its 270+ million annual recreation visits, and therefore provides an opportunity to examine how human visitation may respond to climate change from the tropics to the polar regions. To assess the relationship between climate and park visitation, we evaluated historical monthly mean air temperature and visitation data (1979-2013) at 340 parks and projected potential future visitation (2041-2060) based on two warming-climate scenarios and two visitation-growth scenarios. For the entire park system a third-order polynomial temperature model explained 69% of the variation in historical visitation trends. Visitation generally increased with increasing average monthly temperature, but decreased strongly with temperatures > 25°C. Linear to polynomial monthly temperature models also explained historical visitation at individual parks (R2 0.12-0.99, mean = 0.79, median = 0.87). Future visitation at almost all parks (95%) may change based on historical temperature, historical visitation, and future temperature projections. Warming-mediated increases in potential visitation are projected for most months in most parks (67-77% of months; range across future scenarios), resulting in future increases in total annual visits across the park system (8-23%) and expansion of the visitation season at individual parks (13-31 days). Although very warm months at some parks may see decreases in future visitation, this potential change represents a relatively small proportion of visitation across the national park system. A changing climate is likely to have cascading and complex effects on protected area visitation, management, and local economies. Results suggest that protected areas and neighboring communities that develop adaptation strategies for these changes may be able to both capitalize on opportunities and minimize detriment related to changing visitation. PMID:26083361

  1. The dynamic response of the Greenland and Antarctic ice sheets to multiple-century climatic warming

    SciTech Connect

    Huybrechts, P.; Wolde, J. de

    1999-08-01

    New calculations were performed to investigate the combined response of the Greenland and Antarctic ice sheets to a range of climatic warming scenarios over the next millennium. Use was made of fully dynamic 3D thermomechanic ice sheet models, which were coupled to a two-dimensional climate model. The experiments were initialized with simulations over the last two glacial cycles to estimate the present evolution and were subsequently forced with temperature scenarios resulting from greenhouse emission scenarios which assume equivalent CO{sub 2} increases of two, four, and eight times the present (1990 A.D.) value by the year 2130 A.D. and a stabilization after that. The calculations brought to light that during the next century (short-term effect), the background evolution trend would dominate the response of the Antarctic ice sheet but would be negligible for the Greenland ice sheet. On that timescale, the Greenland and Antarctic ice sheets would roughly balance one another for the middle scenario (similar to the IPCC96 IS92a scenario), with respective contributions to the worldwide sea level stand on the order of about {+-}10 cm. On the longer term, however, both ice sheets would contribute positively to the worldwide sea level stand and the most important effect would come from melting on the Greenland ice sheet. Sensitivity experiments highlighted the role of ice dynamics and the height-mass-balance feedback on the results. It was found that ice dynamics cannot be neglected for the Greenland ice sheet, not even on a century timescale, but becomes only important for Antarctica on the longer term. The latter is related to an increased outflow of ice into the ice shelves and to the grounding-line retreat of the west Antarctic ice sheet, which are both found to be sensitive to basal melting below ice shelves and the effective viscosity of the ice shelves. Stretching parameters to their limits yielded a combined maximum rate of sea level rise of 85 cm century{sup {minus}1}, of which 60 cm would originate from the Greenland ice sheet alone.

  2. Variability in krill biomass links harvesting and climate warming to penguin population changes in Antarctica

    PubMed Central

    Trivelpiece, Wayne Z.; Hinke, Jefferson T.; Miller, Aileen K.; Reiss, Christian S.; Trivelpiece, Susan G.

    2011-01-01

    The West Antarctic Peninsula (WAP) and adjacent Scotia Sea support abundant wildlife populations, many of which were nearly extirpated by humans. This region is also among the fastest-warming areas on the planet, with 5–6 °C increases in mean winter air temperatures and associated decreases in winter sea-ice cover. These biological and physical perturbations have affected the ecosystem profoundly. One hypothesis guiding ecological interpretations of changes in top predator populations in this region, the “sea-ice hypothesis,” proposes that reductions in winter sea ice have led directly to declines in “ice-loving” species by decreasing their winter habitat, while populations of “ice-avoiding” species have increased. However, 30 y of field studies and recent surveys of penguins throughout the WAP and Scotia Sea demonstrate this mechanism is not controlling penguin populations; populations of both ice-loving Adélie and ice-avoiding chinstrap penguins have declined significantly. We argue in favor of an alternative, more robust hypothesis that attributes both increases and decreases in penguin populations to changes in the abundance of their main prey, Antarctic krill. Unlike many other predators in this region, Adélie and chinstrap penguins were never directly harvested by man; thus, their population trajectories track the impacts of biological and environmental changes in this ecosystem. Linking trends in penguin abundance with trends in krill biomass explains why populations of Adélie and chinstrap penguins increased after competitors (fur seals, baleen whales, and some fishes) were nearly extirpated in the 19th to mid-20th centuries and currently are decreasing in response to climate change. PMID:21482793

  3. Space Solar Patrol data and changes in weather and climate, including global warming

    NASA Astrophysics Data System (ADS)

    Avakyan, S. V.; Baranova, L. A.; Leonov, N. B.; Savinov, E. P.; Voronin, N. A.

    2010-08-01

    In this paper, the results obtained during the execution of several ISTC projects are presented. The general aim of these projects has been the study of global changes in the environment, connected with solar activity. A brief description of the optical apparatus of the Space Solar Patrol (SSP) developed and built in the framework of the ISTC projects 385, 385.2, 1523 and 2500 is given. The SSP is intended for permanent monitoring of spectra and absolute fluxes of soft x-ray and extreme ultraviolet (x-ray/EUV) radiation from the full disk of the Sun which ionizes the upper atmosphere of the Earth. Permanent solar monitoring in the main part of the ionizing radiation spectra 0.8-115 (119) nm does not exist. The apparatus of the SSP was developed in the years 1996-2005 with multiyear experience of developing such apparatus in S I Vavilov State Optical Institute. The basis of this apparatus is the use of unique detectors of ionizing radiation—open secondary electron multipliers, which are 'solar blind' to near UV, visible and IR radiation from the Sun, and new methodology of these solar spectroradiometric absolute measurements. The prospects are discussed of using the SSP data for the investigation and forecast of the influence of solar variability on the weather and climate including global warming and also on the biosphere including human beings (proposal 3878). This article was originally submitted for inclusion with the papers from the 9th International Symposium on Measurement Science and Intelligent Instruments (ISMTII-2009), published in the May 2010 issue.

  4. Factors affecting the efficacy of live poliovirus vaccine in warm climates

    PubMed Central

    Dömök, I.; Balayan, M. S.; Fayinka, O. A.; Škrti?, N.; Soneji, A. D.; Harland, P. S. E. G.

    1974-01-01

    A virologically controlled field trial was conducted with live monovalent type 1 poliovirus vaccine in children aged 3-30 months living in a rural area of Uganda, in an attempt to find out the reason for the poor efficacy of such vaccine often observed in countries with a warm climate. Groups of breast-fed and of artificially fed infants received the vaccine orally, either alone or mixed with horse serum prepared against partly purified human gamma-globulin. Irrespective of the diet, the “take rate”—measured by the rates of vaccine virus excretion and of antibody conversion—was found to be poor when the vaccine was given alone but satisfactory when it was given together with the horse antiserum. However, the extent and duration of vaccine virus multiplication in the intestinal tract proved to be limited and the mean antibody level elicited by the vaccination, irrespective of the schedule of vaccine administration, was low. These results, besides indicating that breast-feeding does not influence the efficacy of vaccination in the age groups studied, revealed the presence of an inhibitor in the alimentary tract. This inhibitor acts against the multiplication of vaccine virus, which may be blocked by antibodies in the horse antiserum for a limited period at the time of vaccination. Interference between the enteroviruses and the vaccine strain was also found to be responsible for decreasing the efficacy of vaccination, though its role was secondary to that of the inhibitor. Revaccination experiments showed that the effects of both inhibitor and interference may be overcome by repeated administration of the vaccine. PMID:4142936

  5. Variability in krill biomass links harvesting and climate warming to penguin population changes in Antarctica.

    PubMed

    Trivelpiece, Wayne Z; Hinke, Jefferson T; Miller, Aileen K; Reiss, Christian S; Trivelpiece, Susan G; Watters, George M

    2011-05-01

    The West Antarctic Peninsula (WAP) and adjacent Scotia Sea support abundant wildlife populations, many of which were nearly extirpated by humans. This region is also among the fastest-warming areas on the planet, with 5-6 °C increases in mean winter air temperatures and associated decreases in winter sea-ice cover. These biological and physical perturbations have affected the ecosystem profoundly. One hypothesis guiding ecological interpretations of changes in top predator populations in this region, the "sea-ice hypothesis," proposes that reductions in winter sea ice have led directly to declines in "ice-loving" species by decreasing their winter habitat, while populations of "ice-avoiding" species have increased. However, 30 y of field studies and recent surveys of penguins throughout the WAP and Scotia Sea demonstrate this mechanism is not controlling penguin populations; populations of both ice-loving Adélie and ice-avoiding chinstrap penguins have declined significantly. We argue in favor of an alternative, more robust hypothesis that attributes both increases and decreases in penguin populations to changes in the abundance of their main prey, Antarctic krill. Unlike many other predators in this region, Adélie and chinstrap penguins were never directly harvested by man; thus, their population trajectories track the impacts of biological and environmental changes in this ecosystem. Linking trends in penguin abundance with trends in krill biomass explains why populations of Adélie and chinstrap penguins increased after competitors (fur seals, baleen whales, and some fishes) were nearly extirpated in the 19th to mid-20th centuries and currently are decreasing in response to climate change. PMID:21482793

  6. 11/13/12 Warming climate may starve bamboo-eating pandas -latimes.com 1/4www.latimes.com/news/science/sciencenow/la-sci-sn-giant-panda-20121112,0,1607423.story?track=...

    E-print Network

    'ANTONI PRESCRIPTION DEATHS Search Warming climate may starve bambooeating pandas Already endangered by deforestation, poor reproductive rates and hunting, China's giant pandas may now face a new threat: global warming11/13/12 Warming climate may starve bamboo-eating pandas - latimes.com 1/4www.latimes

  7. The Effects of Urban Warming on Herbivore Abundance and Street Tree Condition

    PubMed Central

    Dale, Adam G.; Frank, Steven D.

    2014-01-01

    Trees are essential to urban habitats because they provide services that benefit the environment and improve human health. Unfortunately, urban trees often have more herbivorous insect pests than rural trees but the mechanisms and consequences of these infestations are not well documented. Here, we examine how temperature affects the abundance of a scale insect, Melanaspis tenebricosa (Comstock) (Hemiptera: Diaspididae), on one of the most commonly planted street trees in the eastern U.S. Next, we examine how both pest abundance and temperature are associated with water stress, growth, and condition of 26 urban street trees. Although trees in the warmest urban sites grew the most, they were more water stressed and in worse condition than trees in cooler sites. Our analyses indicate that visible declines in tree condition were best explained by scale-insect infestation rather than temperature. To test the broader relevance of these results, we extend our analysis to a database of more than 2700 Raleigh, US street trees. Plotting these trees on a Landsat thermal image of Raleigh, we found that warmer sites had over 70% more trees in poor condition than those in cooler sites. Our results support previous studies linking warmer urban habitats to greater pest abundance and extend this association to show its effect on street tree condition. Our results suggest that street tree condition and ecosystem services may decline as urban expansion and global warming exacerbate the urban heat island effect. Although our non-probability sampling method limits our scope of inference, our results present a gloomy outlook for urban forests and emphasize the need for management tools. Existing urban tree inventories and thermal maps could be used to identify species that would be most suitable for urban conditions. PMID:25054326

  8. The effects of urban warming on herbivore abundance and street tree condition.

    PubMed

    Dale, Adam G; Frank, Steven D

    2014-01-01

    Trees are essential to urban habitats because they provide services that benefit the environment and improve human health. Unfortunately, urban trees often have more herbivorous insect pests than rural trees but the mechanisms and consequences of these infestations are not well documented. Here, we examine how temperature affects the abundance of a scale insect, Melanaspis tenebricosa (Comstock) (Hemiptera: Diaspididae), on one of the most commonly planted street trees in the eastern U.S. Next, we examine how both pest abundance and temperature are associated with water stress, growth, and condition of 26 urban street trees. Although trees in the warmest urban sites grew the most, they were more water stressed and in worse condition than trees in cooler sites. Our analyses indicate that visible declines in tree condition were best explained by scale-insect infestation rather than temperature. To test the broader relevance of these results, we extend our analysis to a database of more than 2700 Raleigh, US street trees. Plotting these trees on a Landsat thermal image of Raleigh, we found that warmer sites had over 70% more trees in poor condition than those in cooler sites. Our results support previous studies linking warmer urban habitats to greater pest abundance and extend this association to show its effect on street tree condition. Our results suggest that street tree condition and ecosystem services may decline as urban expansion and global warming exacerbate the urban heat island effect. Although our non-probability sampling method limits our scope of inference, our results present a gloomy outlook for urban forests and emphasize the need for management tools. Existing urban tree inventories and thermal maps could be used to identify species that would be most suitable for urban conditions. PMID:25054326

  9. Potential increase of flood hazards in Korea due to global warming from a high-resolution regional climate simulation

    NASA Astrophysics Data System (ADS)

    Im, E.-S.; Kwon, J.-H.; Lee, B.-J.; In, S.-R.; Han, S.-O.

    2012-04-01

    Because of the importance of the changes in the hydrologic cycle, accurate assessment of precipitation characteristics is essential to understand the impact of climate change due to global warming. This study investigates the changes in extreme precipitation with sub-daily and daily temporal scales. For a fine-scale climate change projection focusing on the Korean peninsula (20 km), we performed the dynamical downscaling of the global climate scenario covering the period 1971-2000 (130-year) simulated by the Max-Planck-Institute global climate model, ECHAM5, using the latest version of the International Centre for Theoretical Physics (ICTP) regional climate model, RegCM3. While annual mean precipitation exhibits a pronounced interannual and interdecadal variability, with the increasing or decreasing trend repeated during a certain period, extreme precipitation with sub-daily and daily temporal scales estimated from the generalized extreme value distribution shows consistently increasing pattern. The return period of extreme precipitation is significantly reduced despite the decreased annual mean precipitation at the end of 21st century. The decreased relatively weak precipitation is responsible for the decreased total precipitation, so that the decreased total precipitation does not necessarily mean less heavy precipitation. Climate change projection based on the ECHAM5-RegCM3 model chain clearly shows the effect of global warming in increasing the intensity and frequency of extreme precipitation, even without significantly increased total precipitation, which implies an increased risk for flood hazards. [Acknowledgements] This work was supported by a grant (code#3100-3136-442) funded by the National Institute of Meteorological Research (NIMR), the Korea Meteorological Administration (KMA).

  10. Impact of the Atlantic Warm Pool on the Summer Climate of the Western Hemisphere CHUNZAI WANG

    E-print Network

    Wang, Chunzai

    The Atlantic warm pool (AWP) is a large body of warm water that comprises the Gulf of Mexico, the Caribbean Sea the tropical North Atlantic into the Caribbean Sea, where the flow intensifies, forming the Caribbean low the semiannual variation of sea level pressure in the Caribbean region owing to the westward extension

  11. Climate Change: Sources of Warming in the Late 20th Century

    E-print Network

    Gerald E. Marsh

    2009-05-28

    The role of the North Atlantic Oscillation, the Pacific Decadal Oscillation, volcanic and other aerosols, as well as the extraordinary solar activity of the late 20th century are discussed in the context of the warming since the mid-1970s. Much of that warming is found to be due to natural causes.

  12. Climate Change: Sources of Warming in the Late 20th Century

    E-print Network

    Marsh, Gerald E

    2009-01-01

    The role of the North Atlantic Oscillation, the Pacific Decadal Oscillation, volcanic and other aerosols, as well as the extraordinary solar activity of the late 20th century are discussed in the context of the warming since the mid-1970s. Much of that warming is found to be due to natural causes.

  13. Response of hurricane-type vortices to global warming as simulated by ARPEGE-Climat at high resolution

    NASA Astrophysics Data System (ADS)

    Chauvin, Fabrice; Royer, Jean-François; Déqué, Michel

    2006-09-01

    Atlantic hurricanes and their sensitivity to anthropogenic warming are investigated using very high (0.5°×0.5° over the Atlantic domain) resolution global simulations. The ARPEGE-Climat variable resolution grid demonstrates its usefulness in regional climate studies since resolution can be multiplied by a factor of 2.5 over the domain of interest compared to a uniform grid, for a similar computer cost. The question of hurricane characteristics dependence on anthropogenic warming is tackled trough the implementation of a tracking method. Changes in the total number, as well as locations, of hurricanes appear to depend more on sea surface temperature (SST) spatial patterns anomaly than Atlantic mean intensity, essentially through the change in large scale vertical wind shear. A uniform SST anomaly forcing produces increased and eastward shifted systems while a spatially contrasted anomaly leads to a decrease. Comparison between cyclogenesis density calculated from tracking or large scale combined variables (as a modified Gray parameter) brings some confidence in the use of the latter to investigate low resolution simulations. Mean hurricane dynamical characteristics are weakly changed by the warming but precipitation core and latent heat flux are enhanced in all scenarios.

  14. Regional Warming from Aerosol Removal over the United States: Results from a Transient 2010-2050 Climate Simulation

    NASA Technical Reports Server (NTRS)

    Mickley, L. J.; Leibensperger, E. M.; Jacob, D. J.; Rind, D.

    2012-01-01

    We use a general circulation model (NASA Goddard Institute for Space Studies GCM 3) to investigate the regional climate response to removal of aerosols over the United States. We perform a pair of transient 2010e2050 climate simulations following a scenario of increasing greenhouse gas concentrations, with and without aerosols over the United States and with present-day aerosols elsewhere. We find that removing U.S. aerosol significantly enhances the warming from greenhouse gases in a spatial pattern that strongly correlates with that of the aerosol. Warming is nearly negligible outside the United States, but annual mean surface temperatures increase by 0.4e0.6 K in the eastern United States. Temperatures during summer heat waves in the Northeast rise by as much as 1e2 K due to aerosol removal, driven in part by positive feedbacks involving soil moisture and low cloud cover. Reducing U.S. aerosol sources to achieve air quality objectives could thus have significant unintended regional warming consequences.

  15. Regional warming from aerosol removal over the United States: Results from a transient 2010-2050 climate simulation

    NASA Astrophysics Data System (ADS)

    Mickley, L. J.; Leibensperger, E. M.; Jacob, D. J.; Rind, D. H.

    2011-12-01

    We use a general circulation model (NASA Goddard Institute for Space Studies GCM 3) to investigate the regional climate response to removal of aerosols over the United States. We perform a pair of transient 2010-2050 climate simulations following a scenario of increasing greenhouse gas concentrations, with and without aerosols over the United States and with present day aerosol concentrations elsewhere. We find that removing U.S. aerosol significantly enhances the warming from greenhouse gases in a spatial pattern that strongly correlates with that of the aerosol. Warming is nearly negligible outside the United States, but annual mean surface temperatures increase by 0.4-0.6 K in the eastern United States. Temperatures during summer heat waves in the Northeast rise by as much as 1-2 K due to aerosol removal, driven in part by positive feedbacks involving soil moisture and low cloud cover. Reducing U.S. aerosol sources to achieve air quality objectives could thus have significant unintended regional warming consequences.

  16. Forecasting conditional climate-change using a hybrid approach

    USGS Publications Warehouse

    Esfahani, Akbar Akbari; Friedel, Michael J.

    2014-01-01

    A novel approach is proposed to forecast the likelihood of climate-change across spatial landscape gradients. This hybrid approach involves reconstructing past precipitation and temperature using the self-organizing map technique; determining quantile trends in the climate-change variables by quantile regression modeling; and computing conditional forecasts of climate-change variables based on self-similarity in quantile trends using the fractionally differenced auto-regressive integrated moving average technique. The proposed modeling approach is applied to states (Arizona, California, Colorado, Nevada, New Mexico, and Utah) in the southwestern U.S., where conditional forecasts of climate-change variables are evaluated against recent (2012) observations, evaluated at a future time period (2030), and evaluated as future trends (2009–2059). These results have broad economic, political, and social implications because they quantify uncertainty in climate-change forecasts affecting various sectors of society. Another benefit of the proposed hybrid approach is that it can be extended to any spatiotemporal scale providing self-similarity exists.

  17. Attribution of soil moisture dynamics - Initial conditions vs. atmospheric forcing and the role of climate change

    NASA Astrophysics Data System (ADS)

    Orth, Rene; Seneviratne, Sonia I.

    2014-05-01

    The world's climate has started to change more quickly in recent decades and a stronger and faster shift is expected in the future. Even if the public perception is mostly limited to a widespread warming, climate change is a complex phenomenon impacting numerous variables of the climate system in different ways, also depending on time and location. Furthermore, extreme events may change more drastically than the mean climate. There is growing evidence that climate change is mostly man-made. However, it is still a matter of debate to which extent changes of the mean climate but also of particular (extreme) events are due to human impact. These questions are addressed by the growing science of climate attribution. Pointing out the anthropogenic influence on extreme events such as the 2010 Russian heatwave or the 2002 floods in Central Europe may help to support adaptation to climate change. This study investigates soil moisture in Europe in the context of climate change, because of its role as a key variable of the land-climate system and its practical importance for instance to agriculture. To derive soil moisture dynamics from 1984-2007 we use E-OBS forcing data together with SRB radiation data and employ an observation-based approach where soil moisture is computed from a water balance equation in which runoff (normalized with precipitation) and ET (normalized with net radiation) are simple functions of soil moisture. The constant runoff function is prescribed for the whole continent, and the ET function is calibrated using temperature data. After performing a validation of the inferred soil moisture data we use it in order to analyze changes in the likelihood of droughts. Our results show increased drought risk especially in north-eastern Europe and the Mediterranean, whereby the probability of extreme droughts increases stronger as for mild dryness episodes. To assess the potential for drought forecasting we furthermore study the importance of the initial conditions versus the atmospheric forcing for monthly soil moisture variations. We find that initial soil moisture anomalies are overall more important than the forcing, even if less pronounced in summer. Especially in southern Europe we show high drought forecasting potential, whereas the forcing is more important in Central and North-eastern Europe.

  18. Multiple population breeding for uncertain climatic futures with Alnus rubra: ecological genetics and

    E-print Network

    Hamann, Andreas

    temperature is expected to rise in future decades, and warming has been predicted to be especially pronounced of climatic warming by simply shifting provenances to new locations. Instead climatic warming may require conditions at the site. Global climate change could cause such a lack of synchronization. The global

  19. Possible land cover change feedbacks to surface albedo and net radiation over Siberia in a warming climate

    NASA Astrophysics Data System (ADS)

    Tchebakova, N.; Parfenova, E.; Soja, A. J.

    2009-12-01

    Our goal was to simulate vegetation cover and hot spots of vegetation change in the changing climate of Siberia by the end of the 21st century and to insight regarding vegetation change feedbacks on the alteration of surface albedo and energy. We applied the Siberian BioClimatic Model (SiBCliM) to the HadCM3 A2 (with the highest temperature increase) and B1 (with the lowest temperature increase) scenarios of the Hadley Centre (IPCC, 2007) to highlight possible vegetation change. SiBCliM predicts a biome (a zonal vegetation class) from three climatic indices (growing degree-days, negative degree-days, and an annual moisture index) and permafrost. Large changes in land cover are predicted from the A2 scenario: coverage by northern vegetation types (tundra, forest-tundra, and taiga) would decrease from 70 to some 30% enabling southern habitats (forest-steppe, steppe and semidesert) to expand coverage from 30 to 70%. Altered land cover would feedback to the climate system resulting in a potential non-linear response to changes in climate. We investigated the effects of land cover change on surface reflectivity (albedo) resulting in net radiation alterations. We calculated annual albedo as the mean of summer albedo during months with no snow cover and winter albedo during months with snow cover. Snow cover appearance and dissappearance were related to surface temperature thresholds 0, 3 and 5 Celsius degrees. Albedo change by 2080 was calculated as the differences between albedo ascribed to each pixel (between 60oE -140oE and 50oN -75oN) according to a vegetation type and snow cover presence/absence in the current and the 2080 climates. In a warmed climate, by 2080, albedo would increase in the southern and middle latitudes in Siberia due to the forest retreat. In the northern latitudes and highlands, tundra would be replaced by the forest with decreased albedo. The total would result in about a 1% albedo increase over the entire area. Under the predicted warmer climate, these calculations suggest that the annual shortwave and consequently net radiation would decrease in 2/3 of the area in the south and would increase in 1/3 of the area in the north resulting in an even greater warming than currently predicted in the high latitudes. Thus, the regional effects of land cover change on climate would be non-linear. This land change projection suggests that the interactive biosphere should be included in global and regional circulation models to get more reliable projections.

  20. Implications of global warming for regional climate and water resources of tropical islands: Case studies over Sri Lanka and Puerto Rico

    NASA Astrophysics Data System (ADS)

    Mawalagedara, R.; Kumar, D.; Oglesby, R. J.; Ganguly, A. R.

    2013-12-01

    The IPCC AR4 identifies small islands as particularly vulnerable to climate change. Here we consider the cases of two tropical islands: Sri Lanka in the Indian Ocean and Puerto Rico in the Caribbean. The islands share a predominantly tropical climate with diverse topography and hence significant spatial variability of regional climate. Seasonal variability in temperatures is relatively small, but spatial variations can be large owing to topography. Precipitation mechanisms and patterns over the two islands are different however. Sri Lanka receives a majority of the annual rainfall from the summer and winter monsoons, with convective rainfall dominating in the inter-monsoon period. Rainfall generating mechanisms over Puerto Rico can range from orographic lifting, disturbances embedded in Easterly waves and synoptic frontal systems. Here we compare the projected changes in the regional and seasonal means and extremes of temperature and precipitation over the two islands during the middle of this century with the present conditions. Two 5-year regional climate model runs for each region, representing the present (2006-2010) and future (2056-2060) conditions, are performed using the Weather Research and Forecasting model with the lateral boundary conditions provided using the output from CCSM4 RCP8.5 greenhouse gas emissions pathway simulation from the CMIP5 ensemble. The consequences of global warming for water resources and the overall economy are examined. While both economies have substantial contributions from tourism, there are major differences: The agricultural sector is much more important over Sri Lanka compared to Puerto Rico, while the latter exhibits no recent growth in population or in urbanization trends unlike the former. Policy implications for water sustainability and security are discussed, which highlight how despite the differences, certain lessons learned may generalize across the two relatively small tropical islands, which in turn have diverse economic, infrastructural, and societal constraints.

  1. Modeling the impact of climate warming on the range of brook trout in the Blue Ridge Mountains, USA

    NASA Astrophysics Data System (ADS)

    Bartlett, M. G.

    2012-12-01

    Brook trout in the Eastern United States (Salvelinus fontinalis) thrive in a relatively narrow range of stream temperatures. Over the past several centuries, the introduction of competitive species has pushed brook trout to the cooler, upstream margins of what use to be a much more extensive range within most drainages. Over the next several decades, climate change may put further thermal pressure on the species, increasing the fragmentation of their distribution and shrinking their present range. Because the size and connectivity of habitats seem to influence the persistence of local populations, climate warming leading to increased fragmentation of remaining habitats could accelerated species decline. Using the Regional Hydrological and Ecological Simulation System (RHYSSys), I modeled the projected habitat changes for a group of native brook trout streams in the Blue Ridge Mountains of South-Central Virginia, USA. The modeling process is illustrative of the need for better understanding of the couplings that exist between geomorphology, hydrology, and ecology, particularly in mountain environments. Model results are quantified according to the degree of decrease in stream-miles of habitat and the increase in the fragmentation of the habitat as a function of the warming rate (degrees per decade). These results may help inform habitat management strategies for the coming several decades in the region, and the modeling process helps highlight the need for more refined understanding of climate change's impacts on habitability.

  2. Assessing the Response of Nematode Communities to Climate Change-Driven Warming: A Microcosm Experiment.

    PubMed

    Gingold, Ruth; Moens, Tom; Rocha-Olivares, Axayácatl

    2013-01-01

    Biodiversity has diminished over the past decades with climate change being among the main responsible factors. One consequence of climate change is the increase in sea surface temperature, which, together with long exposure periods in intertidal areas, may exceed the tolerance level of benthic organisms. Benthic communities may suffer structural changes due to the loss of species or functional groups, putting ecological services at risk. In sandy beaches, free-living marine nematodes usually are the most abundant and diverse group of intertidal meiofauna, playing an important role in the benthic food web. While apparently many functionally similar nematode species co-exist temporally and spatially, experimental results on selected bacterivore species suggest no functional overlap, but rather an idiosyncratic contribution to ecosystem functioning. However, we hypothesize that functional redundancy is more likely to observe when taking into account the entire diversity of natural assemblages. We conducted a microcosm experiment with two natural communities to assess their stress response to elevated temperature. The two communities differed in diversity (high [HD] vs. low [LD]) and environmental origin (harsh vs. moderate conditions). We assessed their stress resistance to the experimental treatment in terms of species and diversity changes, and their function in terms of abundance, biomass, and trophic diversity. According to the Insurance Hypothesis, we hypothesized that the HD community would cope better with the stressful treatment due to species functional overlap, whereas the LD community functioning would benefit from species better adapted to harsh conditions. Our results indicate no evidence of functional redundancy in the studied nematofaunal communities. The species loss was more prominent and size specific in the HD; large predators and omnivores were lost, which may have important consequences for the benthic food web. Yet, we found evidence for alternative diversity-ecosystem functioning relationships, such as the Rivets and the Idiosyncrasy Model. PMID:23825552

  3. Climate Warming May Threaten Reproductive Diapause of a Highly Eusocial Bee.

    PubMed

    Dos Santos, Charles Fernando; Acosta, André Luis; Nunes-Silva, Patrícia; Saraiva, Antonio Mauro; Blochtein, Betina

    2015-08-01

    Climate changes are predicted to affect the diapause of many insect species around the world adversely. In this context, bees are of interest due to their pollination services. In southern Brazil, the highly eusocial bee species Plebeia droryana (Friese) (Hymenoptera: Apidae: Meliponini) exhibits reproductive diapause in response to the region's rigorous winters. That diapause is characterized by a temporary interruption in brood cell construction by nurse bees and egg-laying by the queen, regardless of other internal tasks underway in the nests. In this study, we evaluated whether P. droryana enter diapause under experimental conditions. P. droryana colonies were kept in a germination chamber, and the temperature was progressively reduced from 20°C over a period of a few weeks until diapause was detected. Additionally, we also estimated the environmental conditions in the actual geographic range occupied by P. droryana and modeled it for predicted changes in climate up to the year 2080. Our findings indicate that P. droryana enter diapause between 10 and 8°C. We also found that the current minimum winter temperature (10.1°C, median) in the distributional range of P. droryana will probably rise (13.4°C, median). Thus, if our experimental data are somewhat accurate, ?36% of the southern Brazilian P. droryana population may be active during the expected milder winter months in 2080. In this scenario, there may be a larger demand for pollen and nectar for that bee species. Greater conservation efforts will be required to preserve P. droryana populations and keep them viable in the coming decades. PMID:26314063

  4. ENSO and greenhouse warming

    NASA Astrophysics Data System (ADS)

    Cai, Wenju; Santoso, Agus; Wang, Guojian; Yeh, Sang-Wook; An, Soon-Il; Cobb, Kim M.; Collins, Mat; Guilyardi, Eric; Jin, Fei-Fei; Kug, Jong-Seong; Lengaigne, Matthieu; McPhaden, Michael J.; Takahashi, Ken; Timmermann, Axel; Vecchi, Gabriel; Watanabe, Masahiro; Wu, Lixin

    2015-09-01

    The El Niño/Southern Oscillation (ENSO) is the dominant climate phenomenon affecting extreme weather conditions worldwide. Its response to greenhouse warming has challenged scientists for decades, despite model agreement on projected changes in mean state. Recent studies have provided new insights into the elusive links between changes in ENSO and in the mean state of the Pacific climate. The projected slow-down in Walker circulation is expected to weaken equatorial Pacific Ocean currents, boosting the occurrences of eastward-propagating warm surface anomalies that characterize observed extreme El Niño events. Accelerated equatorial Pacific warming, particularly in the east, is expected to induce extreme rainfall in the eastern equatorial Pacific and extreme equatorward swings of the Pacific convergence zones, both of which are features of extreme El Niño. The frequency of extreme La Niña is also expected to increase in response to more extreme El Niños, an accelerated maritime continent warming and surface-intensified ocean warming. ENSO-related catastrophic weather events are thus likely to occur more frequently with unabated greenhouse-gas emissions. But model biases and recent observed strengthening of the Walker circulation highlight the need for further testing as new models, observations and insights become available.

  5. Comparing Observed Hurricane Conditions Against Potential Future Climate Change Influences

    NASA Astrophysics Data System (ADS)

    Graham, W. D.

    2012-12-01

    Climate Adaptation Science Investigators: (CASI) is to advance and apply NASA's scientific expertise and products to develop climate adaptation strategies that support NASA's overall mission by minimizing risks to each center's operations, physical assets, and personnel. Using Hurricane Katrina observations as a baseline, we use ADCIRC to model surge extent with simple modifications of the storm track. We examine two time now (T0) scenarios of present-day climatological factors: 1) translating the 2005 path 7 km west; and 2) rotating the approach angle from due-north to WNW. Second, we examine two future time scenarios (TX) by infusing climate change conditions, such as sea level rise and increased storm intensity, into a T0 baseline to assess future impacts. The primary goal of this work entails planning and protecting NASA assets and infrastructure. The adjacent communities, state and local emergency managers, gain benefit from this NASA work as data and analysis includes the surrounding geography.

  6. State of the climate in 2010

    E-print Network

    Ganesan, Anita Lakshmi

    Several large-scale climate patterns influenced climate conditions and weather patterns across the globe during 2010. The transition from a warm El Niño phase at the beginning of the year to a cool La Niña phase by July ...

  7. Droughts in a warming climate: A global assessment of Standardized precipitation index (SPI) and Reconnaissance drought index (RDI)

    NASA Astrophysics Data System (ADS)

    Asadi Zarch, Mohammad Amin; Sivakumar, Bellie; Sharma, Ashish

    2015-07-01

    Both drought and aridity indicate imbalance in water availability. While drought is a natural temporal hazard, aridity is a constant climatic feature. This paper investigates the changes in drought characteristics across different aridity zones with and without consideration of potential evapotranspiration (PET), as a means to better assess drought in a warming climate. Two drought indexes are employed: (1) Standardized precipitation index (SPI), which is solely based on precipitation; and (2) Reconnaissance drought index (RDI), which, in addition to precipitation, takes PET into account. The two indexes are first employed to observed precipitation and PET data for the period 1960-2009 from the CRU (Climate Research Unit, University of East Anglia) TS 3.1 database. The results indicate that although all the aridity zones experience both downward and upward drought trends, no significant trend is found over large parts of the zones. However, the agreement between SPI and RDI reduces from the hyper-arid zone on one extreme toward the humid zone on the other. In the three more humid zones (i.e. semi-arid, sub-humid, and humid), the indexes exhibit different trends, with RDI showing more decreasing trends (i.e. becoming drier). While SPI generally shows more drought prone areas than RDI for the pre-1998 period, the opposite is observed for the post-1998 period. Given the known changes to PET in observed records, and also expected increases as global warming intensifies, these results suggest that RDI will be consistently different to the SPI as global warming intensifies. This hypothesis is further tested for historic and future climate projections from the CSIRO (Commonwealth Scientific and Industrial Research Organisation, Australia) Mk3.6 global climate model (GCM), with use of the fifth phase of the Coupled Model Intercomparison Project (CMIP5) and RCP8.5 (Representative Concentration Pathways). In this case, PET is calculated using FAO56-PM model for assessment of RDI. The results suggest that agreement between SPI and RDI is affected and decreases remarkably over time (between 1850 and 2100). All these lead to the conclusion that, in the face of climate change, PET, an important component in the hydrologic cycle, should not be ignored in drought modeling.

  8. Climatic and environmental conditions favoring the crossing of the Carpathians by early Neolithic populations

    NASA Astrophysics Data System (ADS)

    Per?oiu, Ioana; Per?oiu, Aurel

    2015-04-01

    The study of the origin and spread of Neolithic has been the subject of heated debate since the early studies of Childe (1942). To what extent the dispersal process was influenced by environmental factors is still debated, one of the issues being whether climatic conditions influencing agricultural practices, could have influenced the dispersal route, "blocking" some of the Neolithic societies in front of ecological barriers. Data from Neolithic sites in SE Europe shows that a continuous stream of people and cultures flowed through the Danube's Iron Gates towards Central Europe, while in the eastern part of Europe this process was delayed, people and cultures "moving" around the Carpathians and crossing them with a delay of ca. 1000 years. One of the possible avenues for this crossing is the floodplain of Some?u Mic River (Transylvanian depression), home to the oldest (~8500 cal. BP) Neolithic settlement in Romania. In this paper, we review the climatic and environmental changes that affected the region at the time of Neolithic dispersal. Pollen and stable isotopes in cave ice indicate an early Holocene rapid warming during summer months, peaking around 7 ka cal. BP; and a delayed warming for autumn and winter months, peaking at 5 ka cal. BP, both followed by a continuous cooling trend towards the present. Some?u Mic River developed and maintained a narrow sinuous channel during the Holocene, with local development of meanders and anabranches, in response to both climatic and geologic controlling factors. Archaeological finds in the floodplain and the lower terraces suggest that human societies in the region responded in sensitive manner to these climatic and environmental changes. During warm and dry periods, with low fluvial activity, the number of settlements increased in the floodplain's perimeter, while during the short cold and humid periods, the number of settlements rapidly increased on the lower terraces and on the valley slopes, disappearing from the flooded valley bottom and flash-flood prone alluvial fans. Our results suggest that once reaching the foothills of the Carpathian Mts., early Neolithic communities encountered a forested landscape and rather than clearing it for agriculture, they have moved along the middle Danube towards Pannonia and Central Europe, as well as along the lower reaches of the Danube's tributaries, following the most suitable and easily accessible terrain for agriculture practices.

  9. Permafrost degradation and methane: low risk of biogeochemical climate-warming feedback

    E-print Network

    Gao, Xiang

    Climate change and permafrost thaw have been suggested to increase high latitude methane emissions that could potentially represent a strong feedback to the climate system. Using an integrated earth-system model framework, ...

  10. Is bias correction of Regional Climate Model (RCM) simulations possible for non-stationary conditions?

    NASA Astrophysics Data System (ADS)

    Teutschbein, Claudia; Seibert, Jan

    2014-05-01

    Regional Climate Models (RCMs) are commonly used in climate-change impact studies to transfer large-scale Global Climate Model (GCM) values to smaller scales and to provide more detailed regional information. There is, however, the problem that RCM simulations often show considerable deviations from local observations due to systematic and random model errors. This issue has caused the development of several correction approaches, that can be classified according to their degree of complexity and include simple-to-apply methods such as linear transformations but also more advanced methods such as distribution mapping. Most of these common correction approaches are based on the assumption that RCM errors do not change over time. It is in principle not possible to test whether this underlying assumption of error stationarity is actually fulfilled for future climate conditions. In this contribution, however, we show that it is possible to evaluate how well correction methods perform for conditions different from those that they were calibrated to. This can be done with the relatively simple differential split-sample test, originally proposed by Klemeš ["Operational testing of hydrological simulation models", Hydrological Sciences Journal 31, no. 1 (1986): 13-24]. For five Swedish catchments, precipitation and temperature time series from 15 different ERA40-driven RCM simulations were corrected with different commonly-used bias correction methods. We then performed differential split-sample tests by dividing the data series into cold and warm respective dry and wet years. This enabled us to cross-evaluate the performance of different correction procedures under systematically varying climate conditions. The differential split-sample test identified major differences in the ability of the applied correction methods to reduce model errors and to cope with non-stationary biases. More advanced correction methods performed better, whereas large deviations remained for climate model simulations corrected with simpler approaches. Therefore, we question the use of simple correction methods such as the widely used delta-change approach and linear transformation for RCM-based climate-change impact studies. Instead, we recommend using higher-skill correction methods such as distribution mapping.

  11. The influence of menthol on thermoregulation and perception during exercise in warm, humid conditions.

    PubMed

    Gillis, D Jason; House, James R; Tipton, Michael J

    2010-10-01

    Menthol has recently been added to various cooling products that claim to enhance athletic performance. This study assessed the effect of two such solutions during exercise in warm, humid conditions. Twelve participants (22 ± 2.9 years; VO2peak 47.4 ± 6.2 mL kg(-1) min(-1)) completed a peak power (PO(peak)) test and three separate exercise bouts in 30°C and 70% relative humidity after being sprayed with 100 mL of water containing either 0.05 or 0.2% l-menthol, or a control spray. During each trial, participants underwent 15 min of rest, spraying, 15 min of rest and 45 min of exercise at 45% of PO(peak). The following variables were measured: rectal temperature (T (re)), sweat rate (SR), skin blood flow (SBF), heart rate (HR), thermal comfort (TC) and sensation (TS) votes, irritation (IRR) and rating of perceived exertion (RPE). Mean skin (MST) and body temperatures (Tbody) were calculated. There was no significant difference in MST, Tbody SR, SBF, HR, TC or RPE between conditions. Spraying with 0.2% menthol significantly (P < 0.05) elevated T (re) by 0.2°C compared to the other conditions. Both menthol sprays caused participants to feel significantly cooler than control spraying (P = 0.001), but 0.2% spraying induced significantly cooler sensations (P = 0.01) than 0.05% spraying. Both menthol sprays induced greater irritation (P < 0.001) than control spraying. These findings suggest that 0.05% menthol spraying induced cooler upper body sensations without measurable thermoregulatory impairment. T (re) was significantly elevated with 0.2% spraying. Irritation persisted with both menthol sprays while TC remained unchanged, suggesting a causal relationship. The use in sport of a spray similar to those tested here remains equivocal. PMID:20574677

  12. Random walk expectancies for recent global climate, and in an enhanced Greenhouse warming

    NASA Astrophysics Data System (ADS)

    Gordon, Adrian H.; Bye, John A. T.

    1993-11-01

    We partition the United Kingdom Meteorological Office Global Temperature Series ( Tk) using an exponential decay filter into a filtered series ( T?k) and a difference series ( T' k = T k - T?k). For a decay time constant, ? ? 0.85 years, T?k is shown to be agood approximation to a random walk generated by a cumulation of normally distributed interannual temperature transitions, and hence ' k contains the predictable temperature signal. The standard deviation of the T?k series, ? = 0.083K, which is about 1 1/2 that of the T' k series. From this partition, it is argued that ? is the decay time costant (e-folding time) for the global temperature series, and also by the elementary theory of damped oscillations, that the global cimate system (as represented by the global temperature) can only support free oscillations of natural period less than T = 2 ?? ? 5 years, i.e. the QBO and ENSO signals. On assuming that ? does not vary significantly over periods up to 20,000 B.P. we find that the expected maximum excursions of the random walks are consistent with the actual inferred temperature variability. On the other hand, the projected temperature rise due to the enhanced Greenhouse effect possibly cannot be supported as a random walk by ?. This suggests that the interannual structure of the climate system would change under these conditions. This conjecture can be tested adequately only with climate models which correctly reproduced random walk behaviour. This is inhibited in published simulated temperature series from coupled models, possibly because of flux correction. An assessment of the likelihood of a change in the interannual variance, and of the ratio between its predictable and random proportions is clearly of utmost significance in the Greenhouse debate, yet it appears to have received very little discussion.

  13. The origin and limits of the near proportionality between transient climate warming and cumulative CO2 emissions

    NASA Astrophysics Data System (ADS)

    MacDougall, Andrew H.; Friedlingstein, Pierre; Knutti, Reto

    2015-04-01

    The transient climate response to cumulative CO2 emissions (TCRE) is a useful metric of climate warming that directly relates the cause of climate change (cumulative carbon emissions) to the most used index of climate change (global mean near surface temperature change). In this presentation analytical reasoning is used to investigate why TCRE is near constant over a range of cumulative emissions up to 2000 Pg of carbon. In addition, a climate model of intermediate complexity, forced with linear emissions of CO2, is used to explore the effect of the terrestrial carbon cycle feedback strength on TCRE. The analysis reveals that TCRE emerges from the diminishing radiative forcing from CO2 per unit mass being compensated for by the diminishing ability of the ocean to take up heat and carbon. The relationship is maintained as long as the ocean uptake of carbon, which is simulated to be a function of CO2 emissions rate, dominates changes in the airborne fraction of carbon. Strong terrestrial carbon cycle feedbacks have a dependence on the rate of carbon emission and when present lead to TRCE becoming rate dependent. Despite these feedbacks TCRE remains roughly constant over the range of the Representative Concentration Pathways and therefore maintains its primary utility as a metric of climate change. Additional climate model experiments and analytical analysis suggests that a TCRE like metric also emerges in scenarios where CO2 is artificially removed from the atmosphere. However, this reverse TCRE is smaller in magnitude than the TCRE when net CO2 emissions are positive.

  14. Ceramic production during changing environmental/climatic conditions

    NASA Astrophysics Data System (ADS)

    Oestreich, Daniela B.; Glasmacher, Ulrich A.

    2015-04-01

    Ceramics, with regard to their status as largely everlasting everyday object as well as on the basis of their chronological sensitivity, reflect despite their simplicity the technological level of a culture and therefore also, directly or indirectly, the adaptability of a culture with respect to environmental and/or climatic changes. For that reason the question arises, if it is possible to identify changes in production techniques and raw material sources for ceramic production, as a response to environmental change, e.g. climate change. This paper will present results of a research about Paracas Culture (800 - 200 BC), southern Peru. Through several investigations (e.g. Schittek et al., 2014; Eitel and Mächtle, 2009) it is well known that during Paracas period changes in climate and environmental conditions take place. As a consequence, settlement patterns shifted several times through the various stages of Paracas time. Ceramics from three different sites (Jauranga, Cutamalla, Collanco) and temporal phases of the Paracas period are detailed archaeometric, geochemical and mineralogical characterized, e.g. Raman spectroscopy, XRD, and ICP-MS analyses. The aim of this research is to resolve potential differences in the chemical composition of the Paracas ceramics in space and time and to compare the data with the data sets of pre-Columbian environmental conditions. Thus influences of changing environmental conditions on human societies and their cultural conditions will be discussed. References Eitel, B. and Mächtle, B. 2009. Man and Environment in the eastern Atacama Desert (Southern Peru): Holocene climate changes and their impact on pre-Columbian cultures. In: Reindel, M. & Wagner, G. A. (eds.) New Technologies for Archaeology. Berlin Heidelberg: Springer-Verlag. Schittek, K., Mächtle, B., Schäbitz, F., Forbriger, M., Wennrich, V., Reindel, M., and Eitel, B.. Holocene environmental changes in the highlands of the southern Peruvian Andes (14° S) and their impact on pre-Columbian cultures, Clim. Past Discuss., 10, 1707-1746.

  15. Global flood risks under changing climate and socioeconomic conditions

    NASA Astrophysics Data System (ADS)

    Sperna Weiland, Frederiek; Ward, Philip; Bouwman, Arno; Ligtvoet, Willem; van Beek, Rens; Winsemius, Hessel

    2013-04-01

    Worldwide major flood events result in both economic losses and large numbers of casualties. Recent global scale studies indicate that in many regions of the world discharge extremes are likely to increase under changing climate conditions. However, few studies have so far examined how these changes in climate conditions may affect flood risk (defined here as the probability of a flood multiplied by the consequences). In the current study we investigate the impacts of changing climate and socioeconomic conditions on flood extents and depths, and also assess the potential impacts on flood risk. The study is conducted on a global scale, thereby indicating in which regions of the world flood risk is likely to change most. To assess global food risk under changing conditions, we combined socio-economic data from the Integrated Model to Assess the Global Environment (IMAGE) framework of the Netherlands Environmental Assessment Agency (PBL) with high resolution maps of inundation depth (1 km). To this end, projections from a number of GCMs were bias-corrected and used to force the global hydrological model PCR-GLOBWB which simulates (amongst other variables) global maps with daily flood volumes on a 0.5 degree resolution. These time series were used to derive flood volume maps for multiple return periods, which were downscaled to inundation depth maps at 1 km resolution using a 1 km resolution DEM. Finally, these high resolution flood maps were combined with spatial datasets on future GDP and population density from the IMAGE model. Results are presented on both the global scale and at the country level. We believe that the obtained flood extend and flood risk maps can assist development agencies in planning climate adaptation investments that aim to reduce flood risks.

  16. Energy-balance and circulation controls of consistent large-scale temperature responses in warm and cold climates

    NASA Astrophysics Data System (ADS)

    Izumi, K.; Bartlein, P. J.

    2013-12-01

    The Coupled Modelling Intercomparison Project Phase 5 (CMIP5), which requires the same version of models for paleo, historical, and future simulations, combined with large-scale paleoclimatic data syntheses (e.g., the Multiproxy Approach for the reconstruction of Glacial Ocean (MARGO) project, and the quantitative climate reconstructions based on the pollen and plant macrofossil data) allow diagnostic analyses of the mechanisms responsible for the large-scale spatial patterns of temperature that consistently occur in simulations of warm and cold climates. Comparison with the large-scale temperature changes shown by historical observations and by paleoclimate reconstructions also allows us to determine the realism of these responses. We have examined temperature responses in several CMIP5 experiments (lgm, midHolocene, historical, 1pctCO2, and abrupt4xCO2), and used six models (IPSL-CM5A-LR, MPI-ESM-P, MIROC-ESM, CCSM4, MRI-CGCM3, and GISS-E2-R). The simulations show major patterns of past and modern climates changes including 1) the differential response of land-ocean to warming/cooling, 2) the tendency for temperature changes in the higher latitudes to be more extreme than changes in the tropics, and 3) the amplification of seasonality in both warmer/cooler climates. The consistency among simulated and observed large-scale temperature responses shows that these are features of the real climate system that are simulated successfully by models. Moreover, consistency in the simulated patterns of past (e.g., lgm) and future (e.g., abrupt4xCO2) temperature changes implies that a small set of common mechanisms controls the response of the climate system across multiple states. In this study, we explore the key controls for the three large-scale temperature responses in both warmer and cooler climates using a simple energy balance model and analyses of atmospheric circulation changes. Overall, across the range of simulations, variations in clear-sky downward longwave radiation are responsible for the patterns in large-scale temperature anomalies, and in the lgm simulation, this mechanism is augmented by surface albedo feedback.

  17. Fingerprints of the initial conditions on the density profiles of cold and warm dark matter haloes

    E-print Network

    Polisensky, E

    2015-01-01

    We use N-body simulations of dark matter haloes in cold dark matter (CDM) and a large set of different warm dark matter (WDM) cosmologies to demonstrate that the spherically averaged density profile of dark matter haloes has a shape that depends on the power spectrum of matter perturbations. Density profiles are steeper in WDM but become shallower at scales less than one percent of the virial radius. Virialization isotropizes the velocity dispersion in the inner regions of the halo but does not erase the memory of the initial conditions in phase space. The location of the observed deviations from CDM in the density profile and in phase space can be directly related to the ratio between the halo mass and the filtering mass and are most evident in small mass haloes, even for a 34 keV thermal relic WDM. The rearrangement of mass within the haloes supports analytic models of halo structure that include angular momentum. We also find evidence of a dependence of the slope of the inner density profile in CDM cosmolo...

  18. Heart rate variability in sleeping preterm neonates exposed to cool and warm thermal conditions.

    PubMed

    Stéphan-Blanchard, Erwan; Chardon, Karen; Léké, André; Delanaud, Stéphane; Bach, Véronique; Telliez, Frédéric

    2013-01-01

    Sudden infant death syndrome (SIDS) remains the main cause of postneonatal infant death. Thermal stress is a major risk factor and makes infants more vulnerable to SIDS. Although it has been suggested that thermal stress could lead to SIDS by disrupting autonomic functions, clinical and physiopathological data on this hypothesis are scarce. We evaluated the influence of ambient temperature on autonomic nervous activity during sleep in thirty-four preterm neonates (mean ± SD gestational age: 31.4±1.5 weeks, postmenstrual age: 36.2±0.9 weeks). Heart rate variability was assessed as a function of the sleep stage at three different ambient temperatures (thermoneutrality and warm and cool thermal conditions). An elevated ambient temperature was associated with a higher basal heart rate and lower short- and long-term variability in all sleep stages, together with higher sympathetic activity and lower parasympathetic activity. Our study results showed that modification of the ambient temperature led to significant changes in autonomic nervous system control in sleeping preterm neonates. The latter changes are very similar to those observed in infants at risk of SIDS. Our findings may provide greater insight into the thermally-induced disease mechanisms related to SIDS and may help improve prevention strategies. PMID:23840888

  19. Fingerprints of the initial conditions on the density profiles of cold and warm dark matter haloes

    NASA Astrophysics Data System (ADS)

    Polisensky, E.; Ricotti, M.

    2015-06-01

    We use N-body simulations of dark matter haloes in cold dark matter (CDM) and a large set of different warm dark matter (WDM) cosmologies to demonstrate that the spherically averaged density profile of dark matter haloes has a shape that depends on the power spectrum of matter perturbations. Density profiles are steeper in WDM but become shallower at r < 0.01Rvir. Virialization isotropizes the velocity dispersion in the inner regions of the halo but does not erase the memory of the initial conditions in phase space. The location of the observed deviations from CDM in the density profile and in phase space can be directly related to the ratio between the halo mass and the filtering mass and are most evident in small mass haloes, even for a 34 keV thermal relic WDM. The rearrangement of mass within the haloes supports analytic models of halo structure that include angular momentum. We also find evidence of a dependence of the slope of the inner density profile in CDM cosmologies on the halo mass with more massive haloes exhibiting steeper profiles, in agreement with the model predictions and with previous simulation results. Our work complements recent studies of microhaloes near the filtering scale in CDM and strongly argue against a universal shape for the density profile.

  20. Ecoclimatic indicators to study crop suitability in present and future climatic conditionsTIC CONDITIONS

    NASA Astrophysics Data System (ADS)

    Caubel, Julie; Garcia de Cortazar Atauri, Inaki; Huard, Frédéric; Launay, Marie; Ripoche, Dominique; Gouache, David; Bancal, Marie-Odile; Graux, Anne-Isabelle; De Noblet, Nathalie

    2013-04-01

    Climate change is expected to affect both regional and global food production through changes in overall agroclimatic conditions. It is therefore necessary to develop simple tools of crop suitability diagnosis in a given area so that stakeholders can envisage land use adaptations under climate change conditions. The most common way to investigate potential impacts of climate on the evolution of agrosystems is to make use of an array of agroclimatic indicators, which provide synthetic information derived from climatic variables and calculated within fixed periods (i.e. January first - 31th July). However, the information obtained during these periods does not enable to take account of the plant response to climate. In this work, we present some results of the research program ORACLE (Opportunities and Risks of Agrosystems & forests in response to CLimate, socio-economic and policy changEs in France (and Europe). We proposed a suite of relevant ecoclimatic indicators, based on temperature and rainfall, in order to evaluate crop suitability for both present and new climatic conditions. Ecoclimatic indicators are agroclimatic indicators (e.g., grain heat stress) calculated during specific phenological phases so as to take account of the plant response to climate (e.g., the grain filling period, flowering- harvest). These indicators are linked with the ecophysiological processes they characterize (for e.g., the grain filling). To represent this methodology, we studied the suitability of winter wheat in future climatic conditions through three distinct French sites, Toulouse, Dijon and Versailles. Indicators have been calculated using climatic data from 1950 to 2100 simulated by the global climate model ARPEGE forced by a greenhouse effect corresponding to the SRES A1B scenario. The Quantile-Quantile downscaling method was applied to obtain data for the three locations. Phenological stages (emergence, ear 1 cm, flowering, beginning of grain filling and harvest) have been simulated by the STICS, CERES and PANORAMIX crop models with the same input climatic data. Results showed that phenological stages tend to be reached earlier in the future. Significant differences were noted between indicators calculated for invariable calendar periods and indicators calculated during phenological phases. Therefore, ecoclimatic indicators are relevant to provide accurate information about crop suitability in the context of climate change. Whereas most of the indicators do not indicate any significant changes in the future, plant mortality due to frost risks from emergence to ear 1 cm tends to decrease and water supply tends to be more limiting in the future. These indicators do not replace models but represent additional tools for understanding and spatializing some results obtained by models. Their use can provide a spatial distribution of crops according to their suitability in present or future climatic conditions and enable us to minimize the risk of crop failure. It would be interesting to consider the response uncertainties according to the uncertainties we have in future climatic predictions by using different greenhouse emission scenarios and downscaling methods.

  1. Influence of weather-climatic conditions on biospheric processes

    NASA Astrophysics Data System (ADS)

    Govorushko, S. M.

    2012-12-01

    The significance of meteorological processes and phenomena in the biosphere functioning is revealed. The influence of various weather conditions on human health is considered; the factors and mechanisms of their action are described. The impact of meteorological processes on animals is discussed and concrete examples of such impacts are presented. The influence of meteorological processes and phenomena on plants at different stages of their life (pollination, growth, ripening, transport of seeds, damage, and death) and on some abiotic natural components is shown. It is inferred that weather-climatic conditions have a great influence on biospheric processes.

  2. Dissipation of El Niño-like climate conditions through Andean uplift

    NASA Astrophysics Data System (ADS)

    Feng, R.; Poulsen, C. J.

    2013-12-01

    Marine proxies of sea-surface temperature (SST) and thermocline depth have been used to infer an El Niño-like climate state during the Pliocene warm period (~4.5 to 3 Ma ago) consisting of a reduced tropical Pacific SST gradient and deeper thermocline depth in the eastern tropical Pacific. El Niño-like conditions dissipated around ~3 Ma, inaugurating the modern tropical climate. More recent studies extend the Pacific record of northeastern equatorial upwelling to the late Miocene (~13 Ma) and suggest long-term strengthening of the upwelling and shoaling of the thermocline since then. Shoaling is thought to have terminated the El Niño-like climate state by cooling eastern equatorial SSTs and activating the Bjerknes feedback. Late Cenozoic cooling is often proposed as the cause of thermocline shoaling. However, corroborating evidence is still needed given that CO2 levels are thought to have been fairly uniform between 12-5 Ma, and that coupled ocean-atmosphere models simulate a shallow eastern equatorial thermocline even under early Pliocene warmth. Here we propose an alternative cause for SST cooling at eastern tropical Pacific--Late Cenozoic uplift of the Andes. Although the timing and stages of the uplift of the Andes are uncertain, geological evidence suggests significant surface uplift on the order of 2 km since the late Miocene. The sensitivity of the equatorial Pacific climate to Andean uplift is explored using the NCAR Community Climate System Model (CCSM4). In our simulations, the ~2.5 km uplift of central Andes leads to reduction in eastern tropical Pacific SST by 1-2 °C and strengthening of the southeastern Pacific subtropical high and equatorial Easterlies, producing a pattern representative of a La Niña-like state. In addition, the thermocline shoals in the northeastern equatorial Pacific, in agreement with late Miocene marine records. Air-sea interactions are identified as the primary cause of this climate shift because: i) the thermocline adjusts in tandem with variations of wind stress and Ekman transport, and ii) anomalous downwelling occurs at the center of SST cooling (~15 °S) due to densification of chilled seawater. Intensification of the southeastern subtropical high may have triggered this climate shift by enhancing latent heat flux from the ocean through surface evaporation, which accounts for about one-half of the SST cooling. In addition to these climatological changes, the transition from a low to high Andean range also decreases the strength and frequency of (interannual) El Niño events measured by the central equatorial Pacific SSTs (Niño 3.4 index), a possible step in pre-conditioning the Pacific for a more La Niña-like state.

  3. Experimental Warming and Precipitation Effects on Plant Community Composition, Productivity, Nutrient Availability, and Soil Respiration in Pacific Northwest Prairies along a Natural Climate Gradient

    NASA Astrophysics Data System (ADS)

    Bridgham, S. D.; Pfeifer-Meister, L.; Tomaszewski, T.; Reynolds, L.; Goklany, M.; Wilson, H.; Johnson, B. R.

    2011-12-01

    Climate change effects on soil respiration and carbon stores in grasslands globally may have significant implications for future atmospheric carbon dioxide concentrations. Climate change may also may negatively impact native plant species and favor exotic species. We are experimentally increasing temperature by 3 degrees C and increasing precipitation by 25% above ambient in three upland prairie sites along a natural climate gradient from southwestern Oregon to central-western Washington to determine how future climate change will affect (i) plant community composition and the relative success of native versus introduced plant species and (ii) above- and belowground carbon and nutrient dynamics. Sixty plots (20 at each site) were restored by mowing, raking, and herbicide application followed by the sowing of the same 34 native grass and forb species in each plot. Differences in total cover, net primary productivity, and community composition were much greater among sites than among treatments within sites in both 2010--the establishment year, and 2011-the first full year of treatment. Strong successional dynamics occurred over the two years as competition intensified, but these were dependent on a site-treatment interaction, with lower native plant survival in heated plots because of competitive exclusion by exotic, invasive plants. A strong treatment - season interaction in canopy cover (as determined by canopy reflectance) also occurred, with heating causing greater cover during the wet season and lower cover during the dry season. This effect was strongest in the southernmost site which experiences earlier and more intense drought conditions. There were also strong site, treatment, and season interactions on nutrient availability as determined by cation-anion exchange resins. Heating increased nutrient availability in all but the northernmost site during the growing season, and that site also had much lower nutrient availability, but overall availability and site and treatment effects were less during the winter. Plant dynamics among the sites are likely strongly controlled by these differences in nutrient availability. In the winter, heating increased soil respiration, but this effect was lost as the sites warmed and dried during the growing season, with this switch in treatment effect occurring earlier in the spring in the southernmost site. Overall, we have observed many significant effects of the warming and precipitation treatments on plant and ecosystem dynamics, but these effects are often seasonally dependent and of lesser importance than strong differences among sites, driven by differences in soils and the pressure from invasive species. Our experiment shows the importance of placing climate change impacts on natural ecosystems within a context of local ecosystem controls.

  4. Impact of the Medieval Climate Anomaly, Little Ice Age, and Recent Warming on Hydrology and Carbon Accumulation in the James Bay Lowland

    NASA Astrophysics Data System (ADS)

    Holmquist, J. R.; Booth, R. K.; MacDonald, G. M.

    2013-12-01

    Reconstructing late-Holocene hydroclimatic variations can be useful to understand the sensitivity of peatland soil carbon (C) to climate change (Bunbury et al., 2012). We reconstructed water table depth (WTD), using testate amoebae, for a four-core north to south transect of the James Bay Lowland and Boreal Shield of Ontario, Canada, and compared WTD to long-term apparent rate of C accumulation (LARCA). The three southern sites indicate that WTD fluctuated relative to the mean, with a wetter Medieval Climate Anomaly (MCA) and drier Little Ice Age (LIA) (Fig. 1). However, the most northern site recorded a wet LIA and dry MCA (Fig. 1). All four cores recorded drying coincident with modern warming (Fig. 1). Increased Medieval moisture detected in the three southern sites is consistent with a geographic pattern of precipitation anomalies associated with La Niña-like conditions, which cause drought in the American southwest and central plains regions coupled with increased moisture in the Pacific Northwest and north of the Great Lakes (Feng et al., 2008; Seager et al., 2008). Despite the hydroclimatic sensitivity of the region, we observed no consistent relationship between variations in WTD and LARCA from the same cores. At these particular sites, at least, C accumulation has not been sensitive to the range of climatic variability associated with the MCA, LIA and recent warming. Bunbury, J., Finkelstein, S. A., & Bollmann, J. (2012). Holocene hydro-climatic change and effects on carbon accumulation inferred from a peat bog in the Attawapiskat River watershed, Hudson Bay Lowlands, Canada. Quaternary Research: 275-284. Feng, S., Oglesby, R. J., Rowe, C. M., Loope, D. B., & Hu, Q. (2008). Atlantic and Pacific SST influences on Medieval drought in North America simulated by the Community Atmospheric Model. Journal of Geophysical Research: Atmospheres (1984-2012), 113(D11). Seager, R., Burgman, R., Kushnir, Y., Clement, A., Cook, E., Naik, N., & Miller, J. (2008). Tropical Pacific Forcing of North American Medieval Megadroughts: Testing the Concept with an Atmosphere Model Forced by Coral-Reconstructed SSTs. Journal of Climate, 21(23), 6175-6190. The upper plot indicates the most northern site from the discontinuous permafrost zones, The lower plot represents southern sites from the non-permafrost zone.

  5. Premonsoon Aerosol Characterization and Radiative Effects Over the Indo-Gangetic Plains: Implications for Regional Climate Warming

    NASA Technical Reports Server (NTRS)

    Gautam, Ritesh; Hsu, N. Christina; Lau, K.-M.

    2010-01-01

    The Himalayas have a profound effect on the South Asian climate and the regional hydrological cycle, as it forms a barrier for the strong monsoon winds and serves as an elevated heat source, thus controlling the onset and distribution of precipitation during the Indian summer monsoon. Recent studies have suggested that radiative heating by absorbing aerosols, such as dust and black carbon over the Indo-Gangetic Plains (IGP) and slopes of the Himalayas, may significantly accelerate the seasonal warming of the Hindu Kush-Himalayas-Tibetan Plateau (HKHT) and influence the subsequent evolution of the summer monsoon. This paper presents a detailed characterization of aerosols over the IGP and their radiative effects during the premonsoon season (April-May-June) when dust transport constitutes the bulk of the regional aerosol loading, using ground radiometric and spaceborne observations. During the dust-laden period, there is a strong response of surface shortwave flux to aerosol absorption indicated by the diurnally averaged forcing efficiency of -70 W/sq m per unit optical depth. The simulated aerosol single-scattering albedo, constrained by surface flux and aerosol measurements, is estimated to be 0.89+/- 0.01 (at approx.550 nm) with diurnal mean surface and top-of-atmosphere forcing values ranging from -11 to -79.8 W/sq m and +1.4 to +12 W/sq m, respectively, for the premonsoon period. The model-simulated solar heating rate profile peaks in the lower troposphere with enhanced heating penetrating into the middle troposphere (5-6 km), caused by vertically extended aerosols over the IGP with peak altitude of approx.5 km as indicated by spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization observations. On a long-term climate scale, our analysis, on the basis of microwave satellite measurements of tropospheric temperatures from 1979 to 2007, indicates accelerated annual mean warming rates found over the Himalayan-Hindu Kush region (0.21 C/decade+/-0.08 C/decade) and underscores the potential role of enhanced aerosol solar absorption in the maximum warming localized over the western Himalayas (0.26 C/decade f 0.09 C/decade) that significantly exceed the entire HKHT and global warming rates. We believe the accelerated warming rates reported here are critical to both the South Asian summer monsoon and hydro-glaciological resource variability in the Himalayan-Hindu Kush snowpack and therefore to the densely populated downstream regions.

  6. Gross mismatch between thermal tolerances and environmental temperatures in a tropical freshwater snail: climate warming and evolutionary implications.

    PubMed

    Polgar, Gianluca; Khang, Tsung Fei; Chua, Teddy; Marshall, David J

    2015-01-01

    The relationship between acute thermal tolerance and habitat temperature in ectotherm animals informs about their thermal adaptation and is used to assess thermal safety margins and sensitivity to climate warming. We studied this relationship in an equatorial freshwater snail (Clea nigricans), belonging to a predominantly marine gastropod lineage (Neogastropoda, Buccinidae). We found that tolerance of heating and cooling exceeded average daily maximum and minimum temperatures, by roughly 20°C in each case. Because habitat temperature is generally assumed to be the main selective factor acting on the fundamental thermal niche, the discordance between thermal tolerance and environmental temperature implies trait conservation following 'in situ' environmental change, or following novel colonisation of a thermally less-variable habitat. Whereas heat tolerance could relate to an historical association with the thermally variable and extreme marine intertidal fringe zone, cold tolerance could associate with either an ancestral life at higher latitudes, or represent adaptation to cooler, higher-altitudinal, tropical lotic systems. The broad upper thermal safety margin (difference between heat tolerance and maximum environmental temperature) observed in this snail is grossly incompatible with the very narrow safety margins typically found in most terrestrial tropical ectotherms (insects and lizards), and hence with the emerging prediction that tropical ectotherms, are especially vulnerable to environmental warming. A more comprehensive understanding of climatic vulnerability of animal ectotherms thus requires greater consideration of taxonomic diversity, ecological transition and evolutionary history. PMID:25526660

  7. Experimental climate warming enforces seed dormancy in South African Proteaceae but seedling drought resilience exceeds summer drought periods.

    PubMed

    Arnolds, Judith L; Musil, Charles F; Rebelo, Anthony G; Krüger, Gert H J

    2015-04-01

    Two hypotheses-that elevated night-time temperatures due to climate warming would enforce post-fire dormancy of Proteaceae seed due to low moisture, and that periods without rain during summer would exceed desiccation periods tolerated by Proteaceae seedlings-were tested empirically. Enforced dormancy, i.e., the inability to germinate due to an environmental restraint, was tested by measuring seed germination in 11 Proteaceae species in experimental mesocosms whose soils were artificially elevated by 1.4 and 3.5 °C above ambient by far-red wavelength filtered infrared lamps. Diminished totality of germination and velocities were observed in 91 and 64%, respectively, of the Proteaceae species tested. Drought resilience was tested in one-year-old seedlings of 16 Proteaceae species by withholding water from potted plants during summer in a greenhouse. The most drought-resilient Proteaceae species displayed the lowest initial transpiration rates at field capacity, the smallest declines in transpiration rate with decreasing soil water content, and the lowest water losses by transpiration. Projected drought periods leading to the complete cessation of transpiration in all Proteaceae species greatly exceeded the number of days without rain per month during summer in the current distribution ranges of those species. It was therefore concluded that enforced seed dormancy induced by elevated night-time temperatures is the post-fire recruitment stage of Proteaceae that is most sensitive to climate warming. PMID:25502439

  8. Accounts from 19th-century Canadian Arctic explorers' logs reflect present climate conditions

    NASA Astrophysics Data System (ADS)

    Overland, James E.; Wood, Kevin

    The widely perceived failure of 19th-century expeditions to find and transit the Northwest Passage in the Canadian Arctic is often attributed to extraordinary cold climatic conditions associated with the “Little Ice Age” evident in proxy records. However, examination of 44 explorers' logs for the western Arctic from 1818 to 1910 reveals that climate indicators such as navigability, the distribution and thickness of annual sea ice, monthly surface air temperature, and the onset of melt and freeze were within the present range of variability.The quest for the Northwest Passage through the Canadian archipelago during the 19th century is frequently seen as a vain and tragic failure. Polar exploration during the Victorian era seems to us today to have been a costly exercise in heroic futility, which in many respects it was. This perspective has been reinforced since the 1970s, when paleoclimate reconstructions based on Arctic ice core stratigraphy appeared to confirm the existence of exceptionally cold conditions consistent with the period glaciologists had termed the “Little Ice Age” (Figure 1a), with temperatures more than one standard deviation colder relative to an early 20th-century mean [Koerner, 1977; Koerner and Fisher, 1990; Overpeck et al., 1998]. In recent years, the view of the Little Ice Age as a synchronous worldwide and prolonged cold epoch that ended with modern warming has been questioned [Bradley and Jones, 1993; Jones and Briffa, 2001 ;Ogilvie, 2001].

  9. Climate change impacts on mountain glaciers and permafrost Due to their proximity to melting conditions under

    E-print Network

    Raup, Bruce H.

    Editorial Climate change impacts on mountain glaciers and permafrost Due to their proximity to melting conditions under terrestrial conditions, mountain glaciers and permafrost are particularly). Mountain and lowland permafrost are similarly sensitive to climate changes because of their strong

  10. Analyses of the warm season rainfall climatology of the northeastern US using regional climate model simulations and radar rainfall fields

    NASA Astrophysics Data System (ADS)

    Yeung, June K.; Smith, James A.; Villarini, Gabriele; Ntelekos, Alexandros A.; Baeck, Mary Lynn; Krajewski, Witold F.

    2011-02-01

    We examine the warm season (April-September) rainfall climatology of the northeastern US through analyses of high-resolution radar rainfall fields from the Hydro-NEXRAD system and regional climate model simulations using the weather research and forecasting (WRF) model. Analyses center on the 5-year period from 2003 to 2007 and the study area includes the New York-New Jersey metropolitan region covered by radar rainfall fields from the Fort Dix, NJ WSR-88D. The objective of this study is to develop and test tools for examining rainfall climatology, with a special focus on heavy rainfall. An additional emphasis is on rainfall climatology in regions of complex terrain, like the northeastern US, which is characterized by land-water boundaries, large heterogeneity in land use and cover, and mountainous terrain in the western portion of the region. We develop a 5-year record of warm season radar rainfall fields for the study region using the Hydro-NEXRAD system. We perform regional downscaling simulations for the 5-year study period using the WRF model. Radar rainfall fields are used to characterize the interannual, seasonal and diurnal variation of rainfall over the study region and to examine spatial heterogeneity of rainfall. Regional climate model simulations are characterized by a wet bias in the rainfall fields, with the largest bias in the high-elevation regions of the model domain. We show that model simulations capture broad features of the interannual, seasonal, and diurnal variation of rainfall. Model simulations do not capture spatial gradients in radar rainfall fields around the New York metropolitan region and land-water boundaries to the east. The model climatology of convective available potential energy (CAPE) is used to interpret the regional distribution of warm season rainfall and the seasonal and diurnal variability of rainfall. We use hydrologic and meteorological observations from July 2007 to examine the interactions of land surface processes and rainfall from a regional perspective.

  11. Response to CO2 Transient Increase in the GISS Coupled Model: Regional Coolings in a Warming Climate

    NASA Technical Reports Server (NTRS)

    Russell, Gary L.; Rind, David

    1999-01-01

    The (GISS) Goddard Institute for Space Studies coupled atmosphere-ocean model is used to investigate the effect of increased atmospheric CO2 by comparing a compounded 1 percent CO2 increase experiment with a control simulation. After 70 years of integration, the global surface air temperature in the 1 percent CO2 experiment is 1.43 C warmer. In spite of this global warming, there are two distinct regions, the northern Atlantic Ocean and the southern Pacific Ocean, where the surface air temperature is up to 4 C cooler. This situation is maintained by two positive feedbacks: a local effect on convection in the South Pacific and a non-local impact on the meridional circulation in the North Atlantic. The poleward transport of latent energy and dry static energy by the atmosphere is greater in the 1 percent CO2 experiment, caused by warming and therefore increased water vapor and greater greenhouse capacity at lower latitudes. The larger atmospheric transports tend to reduce upward vertical fluxes of heat and moisture from the ocean surface at high latitudes, which has the effect of stabilizing the ocean, reducing both convection and the thermohaline circulation. With less convection, less warm water is brought up from below, and with a reduced North Atlantic thermohaline circulation (by 30 percent at time of CO2 doubling), the poleward energy transport by the oceans decreases. The colder water then leads to further reductions in evaporation, decreases of salinity at high latitudes, continued stabilization of the ocean, and maintenance of reduced convection and meridional overturning. Although sea ice decreases globally, it increases in the cooling regions which reduces the overall climate sensitivity; its effect is most pronounced in the Southern Hemisphere. Tropical warming has been observed over the past several decades; if modeling studies such as this and others which have produced similar effects are valid, these processes may already be beginning.

  12. Response to CO{sub 2} transient increase in the GISS coupled model: Regional coolings in a warming climate

    SciTech Connect

    Russell, G.L.; Rind, D.

    1999-02-01

    The GISS coupled atmosphere-ocean model is used to investigate the effect of increased atmospheric CO{sub 2} by comparing a compounded 1% CO{sub 2} increase experiment with a control simulation. After 70 yr of integration, the global surface air temperature in the 1% CO{sub 2} experiment is 1.43 C warmer. In spite of this global warming, there are two distinct regions, the northern Atlantic Ocean and the southern Pacific Ocean, where the surface air temperature is up to 4 C cooler. This situation is maintained by two positive feedbacks: a local effect on convection in the South Pacific and a nonlocal impact on the meridional circulation in the North Atlantic. The poleward transport of latent energy and dry static energy by the atmosphere is greater in the 1% CO{sub 2} experiment, caused by warming and therefore increased water vapor and greater greenhouse capacity at lower latitudes. The larger atmospheric transports tend to reduce upward vertical fluxes of heat and moisture from the ocean surface at high latitudes, which has the effect of stabilizing the ocean, reducing both convection and the thermohaline circulation. With less convection, less warm water is brought up from below, and with a reduced North Atlantic thermohaline circulation, the poleward energy transport by the oceans decreases. The colder water then leads to further reductions in evaporation, decreases of salinity at high latitudes, continued stabilization of the ocean, and maintenance of reduced convection and meridional overturning. Although sea ice decreases globally, it increases in the cooling regions, which reduces the overall climate sensitivity, especially in the Southern Hemisphere. Tropical warming has been observed over the past several decades; if modeling studies such as this and others that have produced similar effects are valid, these processes may already be beginning.

  13. Relationship between solar irradiance and climatic variability in the subpolar North Atlantic since the Medieval Warm Period

    NASA Astrophysics Data System (ADS)

    Alonso-Garcia, M.; Flower, B. P.; Kleiven, H. F.; Andrews, J. T.

    2011-12-01

    The potential role of solar irradiance as a climate forcing during the Medieval Warm Period (MWP)-Little Ice Age (LIA)-20th Century interval can be tested using several proxies. In this work we use the occurrence of fine sand sized lithic grains (63-150 ?m) in North Atlantic marine sediments to study the climatic history of high latitudes because these lithic grains were ice-rafted either by icebergs or sea-ice. The Holocene ice-rafted debris (IRD) flux is much lower than the IRD flux during glacial periods but the occurrence of hematite-stained grains (HSG) from Paleozoic red beds, Icelandic volcanic glass, and detrital carbonate in the fine sand fraction has been used to track climatic variability at several North Atlantic areas: Feni Drift off Ireland, off eastern Greenland near Denmark Strait, and off Newfoundland (Bond et al, 2001). This controversial work suggested that during the Holocene major ice-rafting discharges matched solar irradiance variability patterns inferred from cosmogenic nuclides (10Be fluxes measured in Greenland ice cores and 14C records from tree rings) and hence, variations in the solar output may have paced centennial- to millennial-scale climate variability in the North Atlantic region. Since 2001 improved 10Be and 14C records have been released and several new sedimentological studies of subpolar North Atlantic marine sites suggested that other climatic forcings may have been involved in Holocene climate variability rather than solar activity (e.g. Moros et al., 2006; Andrews et al., 2009). Moreover, even the ice-rafted origin of the debris has been questioned at some sites. Here we present new high resolution North Atlantic IRD records from Denmark Strait off eastern Greenland and the Labrador Sea, in addition to recounts of sites on the Feni Drift off Ireland (Bond et al., 2001), to study climate variability in the subpolar North Atlantic since MWP. IRD counts are performed using the same technique as in Bond et al. (2001) to (1) replicate Bond's techniques in the same samples/cores, (2) evaluate the coherence of the climate variability across the North Atlantic, and (3) compare these techniques with other IRD proxies such as x-ray diffraction (XRD) records. Furthermore, statistical and time series analyses will be conducted on the IRD concentration record and relative abundances of HSG and volcanic fragments to study the possible cyclicity of increases in icebergs/sea-ice export. The comparison of these IRD records with the new 10Be and 14C records will shed light on the possible linkage between variations in solar irradiance and climate changes that took place during the last ~1000 years, particularly during the LIA.

  14. Climate of Concern--A Search for Effective Strategies for Teaching Children about Global Warming

    ERIC Educational Resources Information Center

    Taber, Fiona; Taylor, Neil

    2009-01-01

    Recent research suggests that the issue of global warming is one of great concern for Australian children. This point to the need for effective teaching about this issue. Children should be properly informed about actions that help reduce carbon emissions as this may give them a sense of empowerment and go some way to alleviating concerns. This…

  15. CLIMATE WARMING AND THE CARBON CYCLE IN THE PERMAFROST ZONE OF THE FORMER SOVIET UNION

    EPA Science Inventory

    The continuous permafrost zone of the former Soviet Union occupies 5% of the land surface area of the earth and stores a significant amount of carbon. limate warming could disrupt the balance between carbon (C) accumulation and decomposition processes within the permafrost zone. ...

  16. Applying Poultry Litter in the Fall to Fertilize Corn May not be Advisable Under Warm Climate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Row crop farmers prefer to apply poultry litter in the fall or winter but whether this practice is safe environmentally and effective for production in regions with warm fall and winter months is not well researched and documented. Research in Mississippi tested the effectiveness of fall- versus spr...

  17. Warmly Debated: The Little Ice Age and the Construction of Historical Climatic Regimes, 1650-1950 

    E-print Network

    Gilson, Christopher R.

    2011-08-08

    . The Medieval Warm Period and the Little Ice Age are the two most commonly referenced and discussed of such regimes. This thesis examines the theories and debates that preceded and surrounded the formal definition of the Little Ice Age as an historic period...

  18. Long-term soil warming and Carbon Cycle Feedbacks to the Climate System

    SciTech Connect

    Melillo, Jerry M.

    2014-04-30

    The primary objective of the proposed research was to quantify and explain the effects of a sustained in situ 5oC soil temperature increase on net carbon (C) storage in a northeastern deciduous forest ecosystem. The research was done at an established soil warming experiment at the Harvard Forest in central Massachusetts – Barre Woods site established in 2001. In the field, a series of plant and soil measurements were made to quantify changes in C storage in the ecosystem and to provide insights into the possible relationships between C-storage changes and nitrogen (N) cycling changes in the warmed plots. Field measurements included: 1) annual woody increment; 2) litterfall; 3) carbon dioxide (CO2) efflux from the soil surface; 4) root biomass and respiration; 5) microbial biomass; and 6) net N mineralization and net nitrification rates. This research was designed to increase our understanding of how global warming will affect the capacity of temperate forest ecosystems to store C. The work explored how soil warming changes the interactions between the C and N cycles, and how these changes affect land-atmosphere feedbacks. This core research question framed the project – What are the effects of a sustained in situ 5oC soil temperature increase on net carbon (C) storage in a northeastern deciduous forest ecosystem? A second critical question was addressed in this research – What are the effects of a sustained in situ 5{degrees}C soil temperature increase on nitrogen (N) cycling in a northeastern deciduous forest ecosystem?

  19. Breeding crops for improved mineral nutrition under climate change conditions.

    PubMed

    Pilbeam, David J

    2015-06-01

    Improvements in understanding how climate change may influence chemical and physical processes in soils, how this may affect nutrient availability, and how plants may respond to changed availability of nutrients will influence crop breeding programmes. The effects of increased atmospheric CO2 and warmer temperatures, both individually and combined, on soil microbial activity, including mycorrhizas and N-fixing organisms, are evaluated, together with their implications for nutrient availability. Potential changes to plant growth, and the combined effects of soil and plant changes on nutrient uptake, are discussed. The organization of research on the efficient use of macro- and micronutrients by crops under climate change conditions is outlined, including analysis of QTLs for nutrient efficiency. Suggestions for how the information gained can be used in plant breeding programmes are given. PMID:25614661

  20. Diverging Responses of Tropical Andean Biomes under Future Climate Conditions

    PubMed Central

    Tovar, Carolina; Arnillas, Carlos Alberto; Cuesta, Francisco; Buytaert, Wouter

    2013-01-01

    Observations and projections for mountain regions show a strong tendency towards upslope displacement of their biomes under future climate conditions. Because of their climatic and topographic heterogeneity, a more complex response is expected for biodiversity hotspots such as tropical mountain regions. This study analyzes potential changes in the distribution of biomes in the Tropical Andes and identifies target areas for conservation. Biome distribution models were developed using logistic regressions. These models were then coupled to an ensemble of 8 global climate models to project future distribution of the Andean biomes and their uncertainties. We analysed projected changes in extent and elevational range and identified regions most prone to change. Our results show a heterogeneous response to climate change. Although the wetter biomes exhibit an upslope displacement of both the upper and the lower boundaries as expected, most dry biomes tend to show downslope expansion. Despite important losses being projected for several biomes, projections suggest that between 74.8% and 83.1% of the current total Tropical Andes will remain stable, depending on the emission scenario and time horizon. Between 3.3% and 7.6% of the study area is projected to change, mostly towards an increase in vertical structure. For the remaining area (13.1%–17.4%), there is no agreement between model projections. These results challenge the common believe that climate change will lead to an upslope displacement of biome boundaries in mountain regions. Instead, our models project diverging responses, including downslope expansion and large areas projected to remain stable. Lastly, a significant part of the area expected to change is already affected by land use changes, which has important implications for management. This, and the inclusion of a comprehensive uncertainty analysis, will help to inform conservation strategies in the Tropical Andes, and to guide similar assessments for other tropical mountains. PMID:23667651

  1. Diverging responses of tropical Andean biomes under future climate conditions.

    PubMed

    Tovar, Carolina; Arnillas, Carlos Alberto; Cuesta, Francisco; Buytaert, Wouter

    2013-01-01

    Observations and projections for mountain regions show a strong tendency towards upslope displacement of their biomes under future climate conditions. Because of their climatic and topographic heterogeneity, a more complex response is expected for biodiversity hotspots such as tropical mountain regions. This study analyzes potential changes in the distribution of biomes in the Tropical Andes and identifies target areas for conservation. Biome distribution models were developed using logistic regressions. These models were then coupled to an ensemble of 8 global climate models to project future distribution of the Andean biomes and their uncertainties. We analysed projected changes in extent and elevational range and identified regions most prone to change. Our results show a heterogeneous response to climate change. Although the wetter biomes exhibit an upslope displacement of both the upper and the lower boundaries as expected, most dry biomes tend to show downslope expansion. Despite important losses being projected for several biomes, projections suggest that between 74.8% and 83.1% of the current total Tropical Andes will remain stable, depending on the emission scenario and time horizon. Between 3.3% and 7.6% of the study area is projected to change, mostly towards an increase in vertical structure. For the remaining area (13.1%-17.4%), there is no agreement between model projections. These results challenge the common believe that climate change will lead to an upslope displacement of biome boundaries in mountain regions. Instead, our models project diverging responses, including downslope expansion and large areas projected to remain stable. Lastly, a significant part of the area expected to change is already affected by land use changes, which has important implications for management. This, and the inclusion of a comprehensive uncertainty analysis, will help to inform conservation strategies in the Tropical Andes, and to guide similar assessments for other tropical mountains. PMID:23667651

  2. MODELING THE POTENTIAL CHANGE IN YIELD AND DISTRIBUTION OF THE EARTH'S CROPS UNDER A WARMED CLIMATE

    EPA Science Inventory

    The large scale distribution of crops is largely determined by climate. e present the results of a climate-crop prediction model based on the U.S. Food & Agriculture Organization crop-suitability approach, implemented in a geographic information system(GIS) environment using seve...

  3. Paleoclimate. Synchronization of North Pacific and Greenland climates preceded abrupt deglacial warming.

    PubMed

    Praetorius, Summer K; Mix, Alan C

    2014-07-25

    Some proposed mechanisms for transmission of major climate change events between the North Pacific and North Atlantic predict opposing patterns of variations; others suggest synchronization. Resolving this conflict has implications for regulation of poleward heat transport and global climate change. New multidecadal-resolution foraminiferal oxygen isotope records from the Gulf of Alaska (GOA) reveal sudden shifts between intervals of synchroneity and asynchroneity with the North Greenland Ice Core Project (NGRIP) ?(18)O record over the past 18,000 years. Synchronization of these regions occurred 15,500 to 11,000 years ago, just prior to and throughout the most abrupt climate transitions of the last 20,000 years, suggesting that dynamic coupling of North Pacific and North Atlantic climates may lead to critical transitions in Earth's climate system. PMID:25061208

  4. Estimates of future warming-induced methane emissions from hydrate offshore west Svalbard for a range of climate models

    NASA Astrophysics Data System (ADS)

    Marín-Moreno, Héctor; Minshull, Timothy A.; Westbrook, Graham K.; Sinha, Bablu

    2015-05-01

    Methane hydrate close to the hydrate stability limit in seafloor sediment could represent an important source of methane to the oceans and atmosphere as the oceans warm. We investigate the extent to which patterns of past and future ocean-temperature fluctuations influence hydrate stability in a region offshore West Svalbard where active gas venting has been observed. We model the transient behavior of the gas hydrate stability zone at 400-500 m water depth (mwd) in response to past temperature changes inferred from historical measurements and proxy data and we model future changes predicted by seven climate models and two climate-forcing scenarios (Representative Concentration Pathways RCPs 2.6 and 8.5). We show that over the past 2000 year, a combination of annual and decadal temperature fluctuations could have triggered multiple hydrate-sourced methane emissions from seabed shallower than 400 mwd during episodes when the multidecadal average temperature was similar to that over the last century (˜2.6°C). These temperature fluctuations can explain current methane emissions at 400 mwd, but decades to centuries of ocean warming are required to generate emissions in water deeper than 420 m. In the venting area, future methane emissions are relatively insensitive to the choice of climate model and RCP scenario until 2050 year, but are more sensitive to the RCP scenario after 2050 year. By 2100 CE, we estimate an ocean uptake of 97-1050 TgC from marine Arctic hydrate-sourced methane emissions, which is 0.06-0.67% of the ocean uptake from anthropogenic CO2 emissions for the period 1750-2011.

  5. Pacific Decadal Variability and Central Pacific Warming El Niño in a Changing Climate

    SciTech Connect

    Di Lorenzo, Emanuele

    2015-02-27

    This research aimed at understanding the dynamics controlling decadal variability in the Pacific Ocean and its interactions with global-scale climate change. The first goal was to assess how the dynamics and statistics of the El Niño Southern Oscillation and the modes of Pacific decadal variability are represented in global climate models used in the IPCC. The second goal was to quantify how decadal dynamics are projected to change under continued greenhouse forcing, and determine their significance in the context of paleo-proxy reconstruction of long-term climate.

  6. On the maintenance of weak meridional temperature gradients during warm climates

    E-print Network

    Korty, Robert Lindsay

    2005-01-01

    This thesis examines the dynamics of equable climates. The underlying physics of two mechanisms by which weak meridional temperature gradients might be maintained are studied. First, I examine the evolution of stratospheric ...

  7. Sensitivity of Climate to Diapycnal Diffusivity: Part I. Equilibrium State; Part II. Global Warming Scenario

    E-print Network

    Dalan, Fabio.

    Part I: The diapycnal diffusivity in the ocean is one of the least known parameters in current climate models. Measurements of this diffusivity are sparse and insufficient for compiling a global map. Inferences from inverse ...

  8. An investigation of carbon flows from forest soils, in relation to climatic warming 

    E-print Network

    Cross, Andrew

    2009-01-01

    Rises in anthropogenic CO2 emissions are now widely acknowledged to be responsible for changes in the global climate, with potentially disastrous consequences if these rises continue unchecked. Although knowledge of ecosystem ...

  9. Future sea-level rise from Greenland's main outlet glaciers in a warming climate.

    PubMed

    Nick, Faezeh M; Vieli, Andreas; Andersen, Morten Langer; Joughin, Ian; Payne, Antony; Edwards, Tamsin L; Pattyn, Frank; van de Wal, Roderik S W

    2013-05-01

    Over the past decade, ice loss from the Greenland Ice Sheet increased as a result of both increased surface melting and ice discharge to the ocean. The latter is controlled by the acceleration of ice flow and subsequent thinning of fast-flowing marine-terminating outlet glaciers. Quantifying the future dynamic contribution of such glaciers to sea-level rise (SLR) remains a major challenge because outlet glacier dynamics are poorly understood. Here we present a glacier flow model that includes a fully dynamic treatment of marine termini. We use this model to simulate behaviour of four major marine-terminating outlet glaciers, which collectively drain about 22 per cent of the Greenland Ice Sheet. Using atmospheric and oceanic forcing from a mid-range future warming scenario that predicts warming by 2.8 degrees Celsius by 2100, we project a contribution of 19 to 30 millimetres to SLR from these glaciers by 2200. This contribution is largely (80 per cent) dynamic in origin and is caused by several episodic retreats past overdeepenings in outlet glacier troughs. After initial increases, however, dynamic losses from these four outlets remain relatively constant and contribute to SLR individually at rates of about 0.01 to 0.06 millimetres per year. These rates correspond to ice fluxes that are less than twice those of the late 1990s, well below previous upper bounds. For a more extreme future warming scenario (warming by 4.5 degrees Celsius by 2100), the projected losses increase by more than 50 per cent, producing a cumulative SLR of 29 to 49 millimetres by 2200. PMID:23657350

  10. WWTP design in warm climates - guideline comparison and parameter adaptation for a full-scale activated sludge plant using mass balancing.

    PubMed

    Walder, C; Lindtner, S; Proesl, A; Klegraf, F; Weissenbacher, N

    2013-01-01

    The ATV-A-131 guideline and the design approach published in 'Wastewater Engineering, Treatment and Reuse (WE)' are widely used for the design of activated sludge plants. They are both based on simplified steady-state assumptions tailored to the boundary conditions of temperate climates. Using design guidelines beyond the designated temperature range may lead to inappropriate results. The objectives of this paper are (1) to summarise temperature relevant differences between ATV-A-131 and WE; (2) to show the related design components; and (3) to demonstrate a procedure for design parameter adaptation for a full-scale activated sludge plant located in a warm climate region. To gain steady-state data required for wastewater treatment plant (WWTP) design according to ATV-A-131 and WE, full-scale plant data were acquired for a period of 6 months as a basis for analyses and adaptation. Mass balances were calculated for the verification of the measurements and for analysing excess sludge production. The two approaches showed relevant temperature related differences. WE default application resulted in lower deviation in the mass balance results for excess sludge production. However, with the adaptation of the heterotrophic decay rates for both approaches and the inert organic and mineral solids fraction additionally for ATV-A-131, a good fit to the observed excess sludge production could be achieved. PMID:23128643

  11. Interpretation of the positive low-cloud feedback predicted by a climate model under global warming

    NASA Astrophysics Data System (ADS)

    Brient, Florent; Bony, Sandrine

    2013-05-01

    The response of low-level clouds to climate change has been identified as a major contributor to the uncertainty in climate sensitivity estimates among climate models. By analyzing the behaviour of low-level clouds in a hierarchy of models (coupled ocean-atmosphere model, atmospheric general circulation model, aqua-planet model, single-column model) using the same physical parameterizations, this study proposes an interpretation of the strong positive low-cloud feedback predicted by the IPSL-CM5A climate model under climate change. In a warmer climate, the model predicts an enhanced clear-sky radiative cooling, stronger surface turbulent fluxes, a deepening and a drying of the planetary boundary layer, and a decrease of tropical low-clouds in regimes of weak subsidence. We show that the decrease of low-level clouds critically depends on the change in the ver