These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Trends of Teleconnection indices that affect Mediterranean climate under warming conditions  

NASA Astrophysics Data System (ADS)

Given the importance of the teleconnections in influencing extreme weather events and representing low frequency variability, the modifications in their structure and changes in the trend under future scenarios are expected to have impacts on regional climates. There are many different studies that link the teleconnections with climate and ecosystems over the Mediterranean area using observed data. In order to investigate possible future impacts in that region is necessary to evaluate the teleconnections with model data under present and future scenarios of climate. Our work is focused on the current four teleconnection indices that affect the Mediterranean climate, the North Atlantic Oscillation (NAO), the East Atlantic pattern (EA), the East Atlantic-Western Russia pattern (EATL/WRUS) and the Scandinavian pattern (SCAND). These indices are reconstructed with CMIP3 models data using the 20C3M and A1B experiments for the periods 1901-1999 and 2000-2098 respectively, on the basis of those defined by the Climate Prediction Center (CPC, NOAA). Previous studies on teleconnections with model data and using EOF analysis indicate the difficulties of the models to reproduce the observed temporal behavior. In our study we filtered from model data the signal of the teleconnection patterns that are defined currently by the CPC by using Partial Least Squares (PLS) regression method. This methodology provides better temporal agreement among observed and model data, which allows us to analyze the trends of the teleconnection indices for present and future. For the period 2000-2098 and winter season, we obtained an increasing trend for the NAO and a decreasing one for the SCAND. These results are consistent with the changes in the trend of the geopotential over the Euro-Atlantic area under warming conditions. Possible connections with changes in the sea surface temperature will be also analyzed. An interest of this work is the potential application for statistical downscaling prediction over this region.

Gonzalez-Reviriego, Nube; Rodriguez-Puebla, Concepción; Rodriguez-Fonseca, Belén

2013-04-01

2

Sea-ice and North Atlantic climate response to CO2-induced warming and cooling conditions  

NASA Astrophysics Data System (ADS)

Using a global climate model coupled with an ocean and a sea-ice model, we compare the effects of doubling CO2 and halving CO2 on sea-ice cover and connections with the atmosphere and ocean. An overall warming in the 2 × CO2 experiment causes reduction of sea-ice extent by 15%, with maximum decrease in summer and autumn, consistent with observed seasonal sea-ice changes. The intensification of the Northern Hemisphere circulation is reflected in the positive phase of the Arctic Oscillation (AO), associated with higher-than-normal surface pressure south of about 50° N and lower-than-normal surface pressure over the high northern latitudes. Strengthening the polar cell causes enhancement of westerlies around the Arctic perimeter during winter. Cooling, in the 0.5 × CO2 experiment, leads to thicker and more extensive sea ice. In the Southern Hemisphere, the increase in ice-covered area (28%) dominates the ice-thickness increase (5%) due to open ocean to the north. In the Northern Hemisphere, sea-ice cover increases by only 8% due to the enclosed land/sea configuration, but sea ice becomes much thicker (108%). Substantial weakening of the polar cell due to increase in sea-level pressure over polar latitudes leads to a negative trend of the winter AO index. The model reproduces large year-to-year variability under both cooling and warming conditions.

Nazarenko, Larissa; Tausnev, Nickolai; Hansen, James

3

The Climate Effects of Deforestation the Amazon Rainforest under Global Warming Conditions  

NASA Astrophysics Data System (ADS)

Replacement of tropical rainforests has been observed to have a strong drying effect in Amazon simulations, with effects reaching high into the atmospheric column and into the midlatitudes. The drying effects of deforestation, however, can be moderated by the effects of global warming, which should accelerate the hydrologic cycle of the Amazon. The effects of a prescribed, time-varying Amazon deforestation done in conjunction with a steady, moderate increase in CO2 concentrations are determined using a climate model. The model agrees with previous studies when each forcing is applied individually - compared to a control run, Amazon deforestation decreases the local precipitation and global warming increases it. When both are applied, however, the precipitation and other hydrologic variables decrease, but to a lesser extent than when deforestation alone was applied. In effect, the two effects act opposite to one another and bring the simulated climate closer to that of the control.

Werth, D.; Avissar, R.

2006-12-01

4

Sea-ice and North Atlantic climate response to CO2-induced warming and cooling conditions  

Microsoft Academic Search

Using a global climate model coupled with an ocean and a sea-ice model, we compare the effects of doubling CO2 and halving CO2 on sea-ice cover and connections with the atmosphere and ocean. An overall warming in the 2 × CO2 experiment causes reduction of sea-ice extent by 15%, with maximum decrease in summer and autumn, consistent with observed seasonal

Larissa Nazarenko; Nickolai Tausnev; James Hansen

2006-01-01

5

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

Microsoft Academic Search

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

G. D. Bell; A. N. Basist

1994-01-01

6

Provision for bearing capacity of permafrost soils in conditions of climate warming  

SciTech Connect

Results are given from numerical calculations of the change in temperature conditions of the permafrost layer and its strength properties with possible warming of the air temperature by 2-4{degrees}C in the next 60 years. The effect of these changes on the bearing capacity of permafrost soils and the associated stability of structures erected in the permafrost zone is evaluated. Measures that provide for stability of these structures by using the natural cold of the North are discussed. It is taken into account that the natural temperature of the permafrost layer changes in a meridional direction from north to south, and that, in connection with this, the sensitivity of permafrost soil to a thermal action also changes.

Vyalov, S.S.; Fotiev, S.M.; Gerasimov, A.S.; Zolotar, A.I. [Moscow State Construction Univ. (Russian Federation)

1994-05-01

7

The Climate Effects of Deforestation the Amazon Rainforest under Global Warming Conditions  

Microsoft Academic Search

Replacement of tropical rainforests has been observed to have a strong drying effect in Amazon simulations, with effects reaching high into the atmospheric column and into the midlatitudes. The drying effects of deforestation, however, can be moderated by the effects of global warming, which should accelerate the hydrologic cycle of the Amazon. The effects of a prescribed, time-varying Amazon deforestation

D. Werth; R. Avissar

2006-01-01

8

Soil degradation, global warming and climate impacts  

E-print Network

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 impacts for differ...- ent watershed regions on the continent. 2. METHODS In order to make a similar comparison between pro- jected climate change scenarios due to global warming © Inter-Research 2001 *E-mail: feddema@ku.edu Soil degradation, global warming and climate...

Feddema, Johannes J.; Freire, Sergio Carneiro

2001-01-01

9

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

SciTech Connect

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.

Bell, G.D.; Basist, A.N. [Climate Analysis Center, Washington, DC (United States)] [Climate Analysis Center, Washington, DC (United States)

1994-10-01

10

Effects of climate warming, North Atlantic Oscillation, and El Niño-Southern Oscillation on thermal conditions and plankton dynamics in northern hemispheric lakes.  

PubMed

Impacts of climate warming on freshwater ecosystems have been documented recently for a variety of sites around the globe. Here we provide a review of studies that report long-term (multidecadal) effects of warming trends on thermal properties and plankton dynamics in northern hemispheric lakes. We show that higher lake temperatures, shorter periods with ice cover, and shorter stagnation periods were common trends for lakes across the hemisphere in response to the warmer conditions. Only for shallow dimictic lakes was it observed that deep-water temperatures decreased. Moreover, it became evident that phytoplankton dynamics and primary productivity altered in conjunction with changes in lake physics. Algal spring blooms developed early and were more pronounced in several European lakes after mild winters with short ice cover periods, and primary productivity increased in North American lakes. Effects of elevated temperatures on zooplankton communities were seen in an early development of various species and groups, as is documented for cladocerans, copepods, and rotifers in European lakes. Furthermore, thermophile species reached higher abundance in warmer years. Obviously, the nature of responses is species specific, and depends on the detailed seasonal patterning of warming. Complex responses such as effects propagating across trophic levels are likely, indicating that observed climate-ecosystem relationships are not generally applicable. Nonetheless, the picture emerges that climate-driven changes in freshwater ecosystems may be synchronised to a certain extent among lakes even over great distances if climatic influences are not masked by anthropogenic impacts or differences in lake morphology. Macro-scale climatic fluctuations--such as the North Atlantic Oscillation or the El Niño-Southern Oscillation--were identified as the most important candidates responsible for such coherence, with the former predominating in Europe and the latter in North America. We emphasise, however, that the driving mechanisms and the future behaviour of these oscillations are rather uncertain, which complicates extrapolation of observed effects into the future. Thus, it is necessary to quantify the most important climate-ecosystem relationships in models of appropriate complexity. Such models will help elucidate the multiple pathways climate affects freshwater ecosystems, and will indicate possible adverse effects of a warmer future climate. PMID:12805986

Gerten, Dieter; Adrian, Rita

2002-03-01

11

Design extremes in a warming climate- A global assessment of changes in antecedent conditions preceding extreme rainfall events with warming temperatures  

NASA Astrophysics Data System (ADS)

Antecedent moisture of a catchment is an important variable that influences, amongst other things, the severity of floods that occurs in a catchment. While there exist several studies that evaluate changes in extreme precipitation as well as attribute such trends to global warming, an assessment of whether or not trends exist in antecedent moisture condition prior to such extreme rain has not been conducted. In this study, antecedent precipitation index (API), a weighted sum of precipitation preceding extreme events, is used as a surrogate measure of antecedent moisture to evaluate possible trends in different regions of the world. To this end, trends in annual API for tropical and extra-tropical regions as well as for each continent across the world are estimated as follows. First, a threshold precipitation is selected to obtain, on average, five extreme precipitation per year at each observation station using daily precipitation data across the world. Second, API at each of these extreme precipitation as well as exceedance probabilities of the API are determined. Finally, trends in the exceedance probabilities of the API together with the associated uncertainty are estimated for the tropics and extra-tropics as well as each continent of the world using the Thiessen polygon method. Estimation of trends based on exceedance probabilities of the API, rather than the API itself, allows to objectively compare trends across different observation stations and regions. We found a significant increasing API trend in Africa, Europe and Australia as well as Extra-tropics regions whereas significant decreasing trend being obtained in South America and the Tropics. The analysis in North America and Asia does not indicate any significant trend. Overall, this study reveals that significant trends exist in the antecedent moisture in many parts of the world, which needs be considered in the estimation of design flood as well as planning and design of hydraulic structures.

Sharma, Ashish; Woldemeskel, Fitsum

2014-05-01

12

Issues of the Global Warming and Climate Change Simulations  

Microsoft Academic Search

This paper discusses the issues of global warming and climate change simulations as a task of the Center for Climate System Research in the COE21 Project. The issues cover better simulation of various feedback processes among atmosphere, ocean, land, and cryosphere, and realistic simulation of physical and chemical condition of the system. One of the goals of the COE21 Project

Teruyuki Nakajima; Masahide Kimoto; Ayako Abe; Hiroyasu Hasumi

13

Impact of climate warming on passive night cooling potential  

Microsoft Academic Search

Night-time ventilation is often seen as a promising passive cooling concept. However, as it requires a sufficiently high temperature difference between ambient air and the building structure, this technique is highly sensitive to changes in climatic conditions. In order to quantify the impact of climate warming on the night-time ventilative cooling potential in Europe, eight representative locations across a latitudinal

N. Artmann; D. Gyalistras; H. Manz; P. Heiselberg

2008-01-01

14

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

PubMed

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

Caballero, Rodrigo; Huber, Matthew

2013-08-27

15

GLOBAL WARMING AND CLIMATE CHANGE MITIGATION TECHNOLOGIES  

Microsoft Academic Search

This paper provides an overview of climate change issues and their related international initiatives to response the challenge of the global warming. It addresses the different technologies for the mitigation of climate changes, including energy efficiency improvement, renewable energy, and greenhouse gas capture and sequestration. It focuses on the technologies of CO2 capture and sequestration and the recent development on

Jinyue Yan

16

The global climate for June to August 1990: Drought returns to sub-Saharan West Africa and warm southern oscillation episode conditions develop in the central pacific  

SciTech Connect

Although the general monsoon circulation evolved relatively normally over most of the globe, dry conditions returned to sub-Saharan West Africa. The Northern Hemisphere summer surface temperature continued to be above normal over most land areas, but in general the anomolies were less extreme. The equatorial sea surface temperatures continued to move toward warm episode Southern Oscillation conditions in the central Pacific, but without an accompanying warming in the traditional eastern Pacific El Nino areas.

Ropelewski, C.F. (Climate Analysis Center, Washington, DC (United States)); Lamb, P.J.; Portis, D.H. (Univ. of Oklahoma, Norman, OK (United States))

1993-11-01

17

Indian Ocean warming modulates Pacific climate change  

PubMed Central

It has been widely believed that the tropical Pacific trade winds weakened in the last century and would further decrease under a warmer climate in the 21st century. Recent high-quality observations, however, suggest that the tropical Pacific winds have actually strengthened in the past two decades. Precise causes of the recent Pacific climate shift are uncertain. Here we explore how the enhanced tropical Indian Ocean warming in recent decades favors stronger trade winds in the western Pacific via the atmosphere and hence is likely to have contributed to the La Niña-like state (with enhanced east–west Walker circulation) through the Pacific ocean–atmosphere interactions. Further analysis, based on 163 climate model simulations with centennial historical and projected external radiative forcing, suggests that the Indian Ocean warming relative to the Pacific’s could play an important role in modulating the Pacific climate changes in the 20th and 21st centuries. PMID:23112174

Luo, Jing-Jia; Sasaki, Wataru; Masumoto, Yukio

2012-01-01

18

Simulating the Warm Climate of the Early Eocene (Invited)  

NASA Astrophysics Data System (ADS)

Past attempts to simulate warm climates of the early Eocene have met with limited success. In particular, simulating the very warm Arctic region and high southern regions has been very difficult to achieve in climate models. This has been of great concern given that we are entering a time period of extreme warming due to increasing levels of atmospheric carbon dioxide. Thus, the question has arisen as to whether current climate models are missing a fundamental feedback that prevents them from capturing high latitude enhanced warming. We present an equilibrium coupled climate simulation using the Community Climate Model (CCSM3) that agrees in many ways with the paleoclimate proxy data for the time period of the Paleocene-Eocene Thermal Maximum (55 Ma). We compare the model simulation to a range of data including sea surface temperatures, benthic temperatures and surface temperatures from terrestrial locations in both the northern and southern hemisphere. The model agrees to within observational uncertainty with this array of data. The model simulation employs increased levels of atmospheric carbon dioxide and methane. We also include a change to warm cloud properties that is based on present day observations for non-industrially affected locations, i.e. naturally occurring aerosol conditions. The concentrations of atmospheric carbon dioxide and methane are within geochemically modeled PETM estimates for these greenhouse gases. We discuss the implications of a warm stratified ocean for modeling atmospheric carbon dioxide levels from simple biogeochemical models and argue that it is important to account for the physical state of the ocean when estimating warm climate greenhouse gas concentrations.

Kiehl, J. T.; Shields, C. A.

2009-12-01

19

WHAT'S IN A NAME? GLOBAL WARMING VERSUS CLIMATE CHANGE  

E-print Network

WHAT'S IN A NAME? GLOBAL WARMING VERSUS CLIMATE CHANGE May 2014 #12;What's In A Name? Global NATIONAL SURVEY STUDY 2: GLOBAL WARMING VS. CLIMATE CHANGE............................ 10 Is global?................................................................10 When you think of global warming / climate change, what comes first to mind

Haller, Gary L.

20

Trophic amplification of climate warming.  

PubMed

Ecosystems can alternate suddenly between contrasting persistent states due to internal processes or external drivers. It is important to understand the mechanisms by which these shifts occur, especially in exploited ecosystems. There have been several abrupt marine ecosystem shifts attributed either to fishing, recent climate change or a combination of these two drivers. We show that temperature has been an important driver of the trophodynamics of the North Sea, a heavily fished marine ecosystem, for nearly 50 years and that a recent pronounced change in temperature established a new ecosystem dynamic regime through a series of internal mechanisms. Using an end-to-end ecosystem approach that included primary producers, primary, secondary and tertiary consumers, and detritivores, we found that temperature modified the relationships among species through nonlinearities in the ecosystem involving ecological thresholds and trophic amplifications. Trophic amplification provides an alternative mechanism to positive feedback to drive an ecosystem towards a new dynamic regime, which in this case favours jellyfish in the plankton and decapods and detritivores in the benthos. Although overfishing is often held responsible for marine ecosystem degeneration, temperature can clearly bring about similar effects. Our results are relevant to ecosystem-based fisheries management (EBFM), seen as the way forward to manage exploited marine ecosystems. PMID:19740882

Kirby, Richard R; Beaugrand, Gregory

2009-12-01

21

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)

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.

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

2014-09-01

22

Climate warming will not decrease winter mortality  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

23

Stream Temperature Sensitivity to Climate Warming in California's Sierra Nevada  

NASA Astrophysics Data System (ADS)

Water temperatures influence the distribution, abundance, and health of aquatic organisms in stream ecosystems. Improving understanding of climate warming on the thermal regime of rivers will help water managers better manage instream habitat. This study assesses climate warming impacts on unregulated stream temperatures in California’s west-slope Sierra Nevada watersheds from the Feather River to the Kern River. We used unregulated hydrology to isolate climate induced changes from those of water operations and land use changes. A 21 year timeseries of weekly instream flow estimates from WEAP21, a spatially explicit rainfall-runoff model were passed to RTEMP, a simplified model based on equilibrium temperature theory, to estimate stream temperatures using net heat exchange, coarse river channel geometry, and exposure time of water to atmospheric conditions. Air temperature was uniformly increased by 2?C, 4?C, and 6?C as a sensitivity analysis to bracket the range of likely outcomes for stream temperatures. Other meteorological conditions, including precipitation, were left unchanged from historical values. Overall, stream temperatures increased by an average of 1.6?C for each 2?C rise in air temperature, and increased most at middle elevations. Thermal heterogeneity existed within and between basins (Figure 1). The high watersheds of the southern Sierra Nevada and the Feather River watershed were less vulnerable to changes in the thermal regime of rivers from climate warming. Precipitation as rainfall instead of snowfall, and low flow conditions were two characteristics that drove water temperatures dynamics with climate warming. These results suggest the thermal regime of rivers will change with climate warming. Viable coldwater habitat will shift to higher elevations and will likely be reduced in California. Understanding potential changes to stream temperatures from climate warming will affect how fish and wildlife are managed, and must be incorporated into modeling studies, restoration assessments, environmental impact statements, and licensing operations of hydropower facilities to best estimate future conditions and achieve desired outcomes. Average annual number of weeks stream temperature exceeds 24°C with incremental uniform 2°C air temperature increases

Null, S.; Viers, J. H.; Deas, M.; Tanaka, S.; Mount, J.

2010-12-01

24

Bering Strait influences climate conditions  

NASA Astrophysics Data System (ADS)

The Atlantic meridional overturning circulation (AMOC) acts as a heat conveyer belt, bringing warm tropical water northward in the Atlantic Ocean and carrying cold dense water back southward. Some studies have suggested that changes in AMOC could result in seesaw-like climate changes between the North Atlantic and North Pacific, in which the North Pacific warms while the North Atlantic cools. In fact, paleoclimate studies have found that such a seesaw effect may have occurred during the Heinrich 1 (H1) event about 15-17.5 thousand years ago. However, global climate conditions are much warmer today than they were during the H1 event. Sea level was much lower during the H1 event, and the Bering Strait, which now connects the North Pacific Ocean to the Arctic Ocean, was closed. Some studies have suggested that AMOC could weaken or even collapse entirely as global climate warms because of anthropogenic influence. Would such AMOC changes lead to the seesaw effect seen during the H1 event?

Balcerak, Ernie

2012-03-01

25

Evaluating the dominant components of warming in Pliocene climate simulations  

NASA Astrophysics Data System (ADS)

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.

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

26

PHENOLOGICAL SEQUENCES REVEAL AGGREGATE LIFE HISTORY RESPONSE TO CLIMATIC WARMING  

Microsoft Academic Search

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

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

2008-01-01

27

Impacts of climate warming on terrestrial ectotherms across latitude  

E-print Network

and adaptation, the greatest extinction risks from global warming may be in the tropics, where biological diversity is also greatest. biodiversity fitness global warming physiology tropical Global warmingImpacts of climate warming on terrestrial ectotherms across latitude Curtis A. Deutsch* , Joshua J

Huey, Raymond B.

28

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

E-print Network

of global warming, responses of arbuscular mycorrhizal fungi (AMF) to climate warm- ing are poorly. of Washington, 260 Panama St., Stanford, CA 94305, USA. The occurrence of global warming, the increase in near-mitigation poli- cies, the 90% probability interval for 1990­2100 global- mean warming is 1.7­4.9°C (Wigley

Rilli, Matthias C.

29

Divergence of reproductive phenology under climate warming  

PubMed Central

Because the flowering and fruiting phenology of plants is sensitive to environmental cues such as temperature and moisture, climate change is likely to alter community-level patterns of reproductive phenology. Here we report a previously unreported phenomenon: experimental warming advanced flowering and fruiting phenology for species that began to flower before the peak of summer heat but delayed reproduction in species that started flowering after the peak temperature in a tallgrass prairie in North America. The warming-induced divergence of flowering and fruiting toward the two ends of the growing season resulted in a gap in the staggered progression of flowering and fruiting in the community during the middle of the season. A double precipitation treatment did not significantly affect flowering and fruiting phenology. Variation among species in the direction and magnitude of their response to warming caused compression and expansion of the reproductive periods of different species, changed the amount of overlap between the reproductive phases, and created possibilities for an altered selective environment to reshape communities in a future warmed world. PMID:17182748

Sherry, Rebecca A.; Zhou, Xuhui; Gu, Shiliang; Arnone, John A.; Schimel, David S.; Verburg, Paul S.; Wallace, Linda L.; Luo, Yiqi

2007-01-01

30

GLOBAL WARMING, CLIMATE CHANGE AND HUMAN PSYCHOLOGY 1  

Microsoft Academic Search

This chapter considers psychological aspects of global warming and climate change. It begins with a brief consideration of the public and political recognition of global warming and climate change as significant environmental issues. The chapter then turns to a review of the scientific evidence of the causes and consequences of climate change, and some of the issues in psychology that

Taciano L. Milfont

31

Lagging adaptation to warming climate in Arabidopsis thaliana  

PubMed Central

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

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

2014-01-01

32

Lagging adaptation to warming climate in Arabidopsis thaliana.  

PubMed

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

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

2014-06-01

33

The response of Picea crassifolia forest to climate warming  

NASA Astrophysics Data System (ADS)

Picea crassifolia forest, an endemic genus mainly distributing in the Qilian Mountain of Northwest China, is very sensitive to climate warming. In the present study, the response of treeline, phenological period, and sap flow of P. crassifolia forest to climate warming were analyzed though a set of observations and experiments. The result showed: (1) During the past 50 years, the temperature had raised at a mean rate of 0.29° C per decade in this region, especially since 1980s (had increased by a total of more than 1.25° C), obviously higher than increment degree IPCC reported. This resulted in the increase of tree recruitment which was significantly positively correlated with the mean growing season temperature and with the mean minimum temperature in June and in winter. Treeline elevation shifted upward by 5.7 to 13.6 m from 1907 to 1957 and by 6.1 to 10.4 m after 1957. (2) By quantifying the canopy phenology events based on satellite-derived datasets (MODIS-NDVI) from 2001 to 2011, and investigating the correlation with climate factors, a conclusion had been drawn which revealed a 3.7 days/decade advance in the length of growing season. Our results suggested that temperature controlled treeline dynamics and phenological period more strongly than precipitation in the Qilian Mountains. (3) In the case of experimental warming (mean daily temperature was increased 0.83° C, mean daily maximum temperature was increased 4.7° C), the trend for the mass growth of P. crassifolia sapling presented a notable increase under conditions of warming, especially for tree height. The data of sap flow showed that warming facilitated the sap flow of sapling in the end of growing season, which indicated the temperature was a major restriction to sap flow rate, especially in the condition of lower temperature.

He, Zhibin; Du, Jun; Yang, Junjun; Chen, Longfei; Zhu, Xi

2014-05-01

34

Background: Global Warming, 2009 1. Unequivocally, the climate is warming. Natural systems are affected.  

E-print Network

Background: Global Warming, 2009 1. Unequivocally, the climate is warming. Natural systems are affected. 2. Very likely (>90% certainty), humans are causing most of the warming. 3. No single technology are very likely to impose net annual costs, which will increase over time as global temperatures increase

Minnesota, University of

35

Early Eocene climate warming increased petroleum production  

NASA Astrophysics Data System (ADS)

From the late Paleocene, about 58 million years ago, to the early Eocene, about 51 million years ago, Earth's surface temperatures warmed by about 5°-10°C. Also in the early Eocene, there was an increase of carbon-13-depleted carbon in the oceans that cannot be accounted for by changes in carbon cycling at the surface. To better understand the source of that carbon, Kroeger and Funnell modeled the thermal evolution of four sedimentary basins in the southwestern Pacific Ocean. The authors show that the rising surface temperatures of the early Eocene eventually led to warming of the sedimentary beds deep beneath the surface. Petroleum can be produced at only a certain range of temperatures; rising temperatures at greater depths would bring more potential source rocks into temperature conditions under which oil and gas can be produced and released.

Balcerak, Ernie

2012-04-01

36

Regional news portrayals of global warming and climate change  

Microsoft Academic Search

In this study we utilize content analysis techniques to examine how the issue of global warming and climate change has been characterized during the period of 1992 through 2005 by the Houston Chronicle—the largest regional newspaper in the Texas coastal region. A total of 795 global warming and climate change news articles from the Houston Chronicle are collected, coded and

Xinsheng Liu; Arnold Vedlitz; Letitia Alston

2008-01-01

37

How to preserve the tundra in a warming climate?  

NASA Astrophysics Data System (ADS)

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.

Käyhkö, Jukka

2014-05-01

38

Ocean Biogeochemistry in the warm climate of the Late Paleocene  

NASA Astrophysics Data System (ADS)

The Late Paleocene is characterized by warm and stable climatic conditions which 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 into 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, which affects the strength and spatial variation of the different carbon pumps. Primary production is only slightly reduced in comparison to 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. Yet, 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 sluggish ocean.

Heinze, M.; Ilyina, T.

2014-04-01

39

The case for a wet, warm climate on early Mars  

NASA Technical Reports Server (NTRS)

The conditions under which Mars could have had a warm wet climate during its early evolution are explored by means of numerical simulations, incorporating more accurate data on the opacity of gaseous CO2 and H2O in the solar and thermal spectral regions (McClatchey et al., 1971) into the one-dimensional radiative-convective greenhouse model of Kasting and Ackerman (1986). The results are presented in extensive graphs and characterized in detail, with consideration of atmospheric CO2 loss rates, sources of atmospheric CO2, CO2 partitioning between atmosphere and hydrosphere, the Mars volatile inventory, the CO2 geochemical cycle, climate evolution, and observational tests. It is concluded that greenhouse conditions (requiring atmospheric CO2 of 1-5 bar) could have existed for a period of about 1 Gyr if the total surficial inventory of CO2 was 2-10 bar.

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

1987-01-01

40

The case for a wet, warm climate on early Mars  

NASA Astrophysics Data System (ADS)

The conditions under which Mars could have had a warm wet climate during its early evolution are explored by means of numerical simulations, incorporating more accurate data on the opacity of gaseous CO2 and H2O in the solar and thermal spectral regions (McClatchey et al., 1971) into the one-dimensional radiative-convective greenhouse model of Kasting and Ackerman (1986). The results are presented in extensive graphs and characterized in detail, with consideration of atmospheric CO2 loss rates, sources of atmospheric CO2, CO2 partitioning between atmosphere and hydrosphere, the Mars volatile inventory, the CO2 geochemical cycle, climate evolution, and observational tests. It is concluded that greenhouse conditions (requiring atmospheric CO2 of 1-5 bar) could have existed for a period of about 1 Gyr if the total surficial inventory of CO2 was 2-10 bar.

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

1987-08-01

41

Tropical Cyclogenesis Factors in a Warming Climate  

E-print Network

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...

Cathey, Stephen Christopher

2012-02-14

42

A warm Miocene climate at low atmospheric CO2 levels  

Microsoft Academic Search

Proxy records from the Miocene epoch (~23-5 Ma) indicate a warmer climate than today in spite of lower atmospheric carbon dioxide (CO2) concentrations in the range of preindustrial levels. As yet the simulation of a warm Miocene climate with these low CO2 values has proven to be a challenge. In this study we present climate simulations of the Late Miocene

G. Knorr; M. Butzin; A. Micheels; G. Lohmann

2011-01-01

43

Precipitation scaling with temperature in warm and cold climates: An analysis of CMIP5 simulations  

NASA Astrophysics Data System (ADS)

investigate the scaling between precipitation and temperature changes in warm and cold climates using six models that have simulated the response to both increased CO2 and Last Glacial Maximum (LGM) boundary conditions. Globally, precipitation increases in warm climates and decreases in cold climates by between 1.5%/°C and 3%/°C. Precipitation sensitivity to temperature changes is lower over the land than over the ocean and lower over the tropical land than over the extratropical land, reflecting the constraint of water availability. The wet tropics get wetter in warm climates and drier in cold climates, but the changes in dry areas differ among models. Seasonal changes of tropical precipitation in a warmer world also reflect this "rich get richer" syndrome. Precipitation seasonality is decreased in the cold-climate state. The simulated changes in precipitation per degree temperature change are comparable to the observed changes in both the historical period and the LGM.

Li, Guangqi; Harrison, Sandy P.; Bartlein, Patrick J.; Izumi, Kenji; Colin Prentice, I.

2013-08-01

44

The European climate under a 2?°C global warming  

NASA Astrophysics Data System (ADS)

A global warming of 2?°C relative to pre-industrial climate has been considered as a threshold which society should endeavor to remain below, in order to limit the dangerous effects of anthropogenic climate change. The possible changes in regional climate under this target level of global warming have so far not been investigated in detail. Using an ensemble of 15 regional climate simulations downscaling six transient global climate simulations, we identify the respective time periods corresponding to 2?°C global warming, describe the range of projected changes for the European climate for this level of global warming, and investigate the uncertainty across the multi-model ensemble. Robust changes in mean and extreme temperature, precipitation, winds and surface energy budgets are found based on the ensemble of simulations. The results indicate that most of Europe will experience higher warming than the global average. They also reveal strong distributional patterns across Europe, which will be important in subsequent impact assessments and adaptation responses in different countries and regions. For instance, a North-South (West-East) warming gradient is found for summer (winter) along with a general increase in heavy precipitation and summer extreme temperatures. Tying the ensemble analysis to time periods with a prescribed global temperature change rather than fixed time periods allows for the identification of more robust regional patterns of temperature changes due to removal of some of the uncertainty related to the global models’ climate sensitivity.

Vautard, Robert; Gobiet, Andreas; Sobolowski, Stefan; Kjellström, Erik; Stegehuis, Annemiek; Watkiss, Paul; Mendlik, Thomas; Landgren, Oskar; Nikulin, Grigory; Teichmann, Claas; Jacob, Daniela

2014-03-01

45

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

PubMed

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

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

2014-10-01

46

Climate Warming Postpones Senescence in High Arctic Tundra  

Microsoft Academic Search

Lengthening of the growing season at high latitudes, observed by satellites with the Normalized Difference Vegetation Index (NDVI), has been ascribed to climate warming. To test this assumption, and to verify whether changes in vegetation greenness are quantitative or qualitative, we experimentally warmed patches of High Arctic tundra with infrared heating in Northeast Greenland. By analyzing digital images of the

Fleur L. Marchand; Ivan Nijs; Mark Heuer; Sofie Mertens; Fred Kockelbergh; Jean-Yves Pontailler; Ivan Impens; Louis Beyens

2004-01-01

47

Permafrost carbon-climate feedbacks accelerate global warming  

E-print Network

Permafrost carbon-climate feedbacks accelerate global warming Charles D. Kovena,b,1 , Bruno, and approved July 12, 2011 (received for review March 24, 2011) Permafrost soils contain enormous amounts respiration rates with warming. We have used a terrestrial ecosystem model that includes permafrost carbon

48

Patterns of decadal-scale Arctic warming events in simulated climate  

NASA Astrophysics Data System (ADS)

Pronounced positive decadal-scale temperature anomalies occurred in the Arctic region in the first half of the twentieth century, an episode known as the early twentieth century warming (ETCW). Analyzing a 3,000-year unperturbed climate simulation performed with the Max Planck Institute Earth System Model, we demonstrate that internal variability of the Northern Hemisphere climate system is sufficient to reproduce warm events matching the observed ETCW. We perform a superposed epoch analysis on simulated data and identify 26 Arctic warming episodes compatible with the ETCW. The simulated events reproduce, in their ensemble average, magnitude as well as spatial and temporal extent of the observed ETCW. In individual realizations, the ETCW-like events indicate that different patterns of internally generated decadal Arctic warming are possible, including pan-Arctic warming events. We investigate the dynamics that typically lead to the simulated warming events: positive oceanic heat transport anomalies that form in the North Atlantic initialize the warming events and trigger an ocean-ice-albedo feedback in the Barents Sea region. The consequent reduction in sea-ice extent leads to enhanced multi-year surface warming through strengthened ocean heat release to the atmosphere. The oceanic heat transport anomalies reduce to pre-event levels around the year of the maximum warming. However, the warming events typically lasts for another 5-7 years until the sea-ice extent recovers to pre-event conditions.

Beitsch, Alexander; Jungclaus, Johann H.; Zanchettin, Davide

2014-10-01

49

Altered hydrologic feedback in a warming climate introduces a “warming hole”  

Microsoft Academic Search

(2) Changes in forcing of the climate system can trigger new or altered feedback processes. We have found evidence of such a feedback in the hydrological cycle of the central U.S. that creates a regional minimum within the continental- scale pattern of warming in an enhanced greenhouse-gas climate. The effect of this particular feedback is amplified because a change is

Zaitao Pan; Raymond W. Arritt; Eugene S. Takle; William J. Gutowski Jr; Christopher J. Anderson; Moti Segal

2004-01-01

50

Phenological sequences reveal aggregate life history response to climatic warming.  

PubMed

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

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

2008-02-01

51

Impact of global warming and climate change on social development  

Microsoft Academic Search

In recent years there has been a lot of discussion on global warming and climate change and its implications for social development – an area that Mohan has devoted his life to. It is now accepted that climate change is real and its impacts will be felt across different sectors ranging from water resources to industries to social arenas. In

Ashok K. Mishra; Vijay P. Singh; Sharad K. Jain

2010-01-01

52

The Impact of Boreal Forest Fire on Climate Warming  

E-print Network

in carbon accumulation (12), so the net effect of land cover change on climate may be close to neutral carbon deposition on snow and sea ice, and postfire changes in surface albedo. The net effect of all gases emitted by fire contribute to climate warming, understanding the net effect of a changing fire

Zender, Charles

53

The impact of possible climate catastrophes on global warming policy  

Microsoft Academic Search

Recent studies on global warming have introduced the inherent uncertainties associated with the costs and benefits of climate policies and have often shown that abatement policies are likely to be less aggressive or postponed in comparison to those resulting from traditional cost–benefit analyses (CBA). Yet, those studies have failed to include the possibility of sudden climate catastrophes. The aim of

Andrea Baranzini; Marc Chesney; Jacques Morisset

2003-01-01

54

Global warming and Arctic climate. Raymond S. Bradley  

E-print Network

Global warming and Arctic climate. Raymond S. Bradley Climate System Research Center University of Massachusetts Amherst #12;How have global temperatures changed & why? 1. Average instrumental records from around the world; express all as anomalies from 1961-90 average #12;#12;Overall trend is upward ("global

Mountziaris, T. J.

55

Implication of climate warming for agricultural production in eastern China  

SciTech Connect

According to the regional climate change scenarios for China estimated by the composite GCM, the potential impacts of climate warming on rice, winter wheat and corn production in eastern agricultural areas and cropping systems in China in future 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 climate warming effect upon the corn production is the most significant, impact upon the winter wheat is the next one and the smallest one is that upon the rice. The regional and seasonal features of impacts on various crops are rather different. And also, there will be a substantial northward shift of the cropping patterns, such as the northern boundary of triple cropping area would shift from its current border at Yangtze River toward Yellow River. However, it is still difficult to draw a specific conclusion that climate warming will be advantageous or disadvantageous for farm in China, because of significant negative balance between precipitation and evapotranspiration increase and a lot of scientific uncertainties in the investigation of climate warming, GCM prediction and complex-various impact of climate warming on agricultural production.

Wang Futang [Chinese Academy of Meteorological Science, Beijing (China)

1996-03-01

56

Improved proxy record of past warm climates needed  

NASA Astrophysics Data System (ADS)

Before the end of the present century, atmospheric carbon dioxide (CO2) is projected to reach the high levels last seen in past warm periods such as the Eocene (˜40 million years ago) [Beerling and Royer, 2011]. Climate reconstructions from sediment cores (“proxy data”) and paleoclimate modeling studies show that such higher CO2 periods are characterized by warmer temperatures, smaller ice sheets, and higher sea level than today. The proxy record of past warm climates is thus fundamental in guiding scientists' understanding of future climate changes. However, we believe that currently available data sets are not yet adequate for this task.

Langebroek, Petra; Bradshaw, Catherine; Yanchilina, Anastasia; Caballero-Gill, Rocio; Pew, Caroline; Armour, Kyle; Lee, Shih-Yu; Jansson, Ida-Maria

2012-04-01

57

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

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

Restrepo, Juan M.

58

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

NASA Astrophysics Data System (ADS)

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.

Shongwe, M. E.

2010-01-01

59

Alien plant species favoured over congeneric natives under experimental climate warming in temperate Belgian climate  

Microsoft Academic Search

Climate warming and biological invasions by alien species are two key factors threatening the world’s biodiversity. To date,\\u000a their impact has largely been studied independently, and knowledge on whether climate warming will promote invasions relies\\u000a strongly on bioclimatic models. We therefore set up a study to experimentally compare responses to warming in native and alien\\u000a plant species. Ten congeneric species pairs were

M. Verlinden; I. Nijs

2010-01-01

60

Global Warming - The Science of Climate Change  

Microsoft Academic Search

Extremely topical over recent years, global warming has been the subject of a huge and growing amount of literature. Current literature however tends to fall into two camps: that which is highly scientific in nature and inaccessible to the average student, and that which is directed to the \\

Frances Drake

2000-01-01

61

Impacts of tropical ocean warming on East Asian summer climate  

NASA Astrophysics Data System (ADS)

The impacts of eastern Pacific (EP) and Indian Ocean (IO) warming after the late 1970s on the East Asian climate in July and August were investigated, to understand the distinct impacts of the abovementioned warming on differences in sub-seasonal characteristics. The EP warming induced a strong Pacific-Japan (PJ)-like (tropics-related meridional) pattern during July, but the IO warming preferred a Eurasian (EU)-like wave (extratropics-related zonal) pattern during August. The former is weaker in August and the latter in July. Additionally, the results of perpetual July and August model experiments revealed that these distinct atmospheric responses to the EP and IO warming during July and August, respectively, were caused by different mean thermal states. The difference in the mean thermal states was mainly derived from (1) a warmer ocean and cooler continent in August than in July and (2) a warmer tropics and cooler extratropics in July than in August.

Yun, Kyung-Sook; Ha, Kyung-Ja; Wang, Bin

2010-10-01

62

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....

63

Hydrologic Response and Watershed Sensitivity to Climate Warming in California's Sierra Nevada  

PubMed Central

This study focuses on the differential hydrologic response of individual watersheds to climate warming within the Sierra Nevada mountain region of California. We describe climate warming models for 15 west-slope Sierra Nevada watersheds in California under unimpaired conditions using WEAP21, a weekly one-dimensional rainfall-runoff model. Incremental climate warming alternatives increase air temperature uniformly by 2°, 4°, and 6°C, but leave other climatic variables unchanged from observed values. Results are analyzed for changes in mean annual flow, peak runoff timing, and duration of low flow conditions to highlight which watersheds are most resilient to climate warming within a region, and how individual watersheds may be affected by changes to runoff quantity and timing. Results are compared with current water resources development and ecosystem services in each watershed to gain insight into how regional climate warming may affect water supply, hydropower generation, and montane ecosystems. Overall, watersheds in the northern Sierra Nevada are most vulnerable to decreased mean annual flow, southern-central watersheds are most susceptible to runoff timing changes, and the central portion of the range is most affected by longer periods with low flow conditions. Modeling results suggest the American and Mokelumne Rivers are most vulnerable to all three metrics, and the Kern River is the most resilient, in part from the high elevations of the watershed. Our research seeks to bridge information gaps between climate change modeling and regional management planning, helping to incorporate climate change into the development of regional adaptation strategies for Sierra Nevada watersheds. PMID:20368984

Null, Sarah E.; Viers, Joshua H.; Mount, Jeffrey F.

2010-01-01

64

Hydrologic response and watershed sensitivity to climate warming in California's Sierra Nevada.  

PubMed

This study focuses on the differential hydrologic response of individual watersheds to climate warming within the Sierra Nevada mountain region of California. We describe climate warming models for 15 west-slope Sierra Nevada watersheds in California under unimpaired conditions using WEAP21, a weekly one-dimensional rainfall-runoff model. Incremental climate warming alternatives increase air temperature uniformly by 2 degrees, 4 degrees, and 6 degrees C, but leave other climatic variables unchanged from observed values. Results are analyzed for changes in mean annual flow, peak runoff timing, and duration of low flow conditions to highlight which watersheds are most resilient to climate warming within a region, and how individual watersheds may be affected by changes to runoff quantity and timing. Results are compared with current water resources development and ecosystem services in each watershed to gain insight into how regional climate warming may affect water supply, hydropower generation, and montane ecosystems. Overall, watersheds in the northern Sierra Nevada are most vulnerable to decreased mean annual flow, southern-central watersheds are most susceptible to runoff timing changes, and the central portion of the range is most affected by longer periods with low flow conditions. Modeling results suggest the American and Mokelumne Rivers are most vulnerable to all three metrics, and the Kern River is the most resilient, in part from the high elevations of the watershed. Our research seeks to bridge information gaps between climate change modeling and regional management planning, helping to incorporate climate change into the development of regional adaptation strategies for Sierra Nevada watersheds. PMID:20368984

Null, Sarah E; Viers, Joshua H; Mount, Jeffrey F

2010-01-01

65

Climatic Research Unit Percentage of cold nights (Tn10p) and warm nights (Tn90p)  

E-print Network

Climatic Research Unit Percentage of cold nights (Tn10p) and warm nights (Tn90p) & percentage of cold days (Tx10p) and warm days (Tx90p) 1950-2004 Trends in warm nights (Tn90p) 1950-2004 Climate and Atmospheric Climate Change. In: Climate Change 2007: The Physical Science Basis. Working Group I. 4th IPCC

Feigon, Brooke

66

Global Warming and Climate Change Science  

Microsoft Academic Search

Global climate change has emerged as a major scientific and political issue within a few short decades. Scientific evidence clearly indicates that this change is a result of a complex interplay between a number of human-related and natural earth systems. While the complexity of the earth-ocean-atmosphere system makes the understanding and prediction of global climate change very difficult, improved scientific

Atul Jain

2008-01-01

67

Climate and conflicts: the security risks of global warming  

Microsoft Academic Search

Since the publication of the fourth assessment report of the Intergovernmental Panel on Climate Change in 2007, the securitization\\u000a of global warming has reached a new level. Numerous public statements and a growing research literature have discussed the\\u000a potential security risks and conflicts associated with climate change. This article provides an overview of this debate and\\u000a introduces an assessment framework

Jürgen Scheffran; Antonella Battaglini

2011-01-01

68

Global Warming, Climate Change and Glacier Retreat of Nepal Himalayas  

Microsoft Academic Search

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

S. Shrestha; Y. Hisaki

2007-01-01

69

Climatic warming increases isoprene emission from a subarctic heath.  

PubMed

Emissions of isoprene, a reactive hydrocarbon, from Subarctic vegetation are not well documented. However, the Arctic is likely to experience the most pronounced effects of climatic warming, which may increase temperature-dependent isoprene emission. Here, we assessed isoprene emission from a Subarctic heath subjected to a 3-4 degrees C increase in air temperature and mountain birch (Betula pubescens ssp. czerepanovii) litter addition for 7-8 yr, simulating climatic warming and the subsequent expansion of deciduous shrub species and migration of the treeline. The measurements were performed using the dynamic chamber method on a wet heath with a mixture of shrubs, herbs and graminoids. Isoprene emissions averaged across the treatments were 36 +/- 5 microg m(-2) h(-1) in 2006 and 58 +/- 7 microg m(-2) h(-1) in 2007. The experimental warming increased the emissions by 83% in 2007 (P = 0.021) and by 56% in 2006 (P = 0.056), while litter addition had no significant effects. The net ecosystem CO(2) exchange was significantly decreased by warming in 2007. These results show that isoprene emissions from Subarctic heaths are comparable to those from Subarctic peatlands. Climatic warming will increase the emissions, and the amount of carbon lost as isoprene, from Subarctic heath ecosystems. PMID:18680543

Tiiva, Päivi; Faubert, Patrick; Michelsen, Anders; Holopainen, Toini; Holopainen, Jarmo K; Rinnan, Riikka

2008-01-01

70

Climate warming and disease risks for terrestrial and marine biota.  

PubMed

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. PMID:12077394

Harvell, C Drew; Mitchell, Charles E; Ward, Jessica R; Altizer, Sonia; Dobson, Andrew P; Ostfeld, Richard S; Samuel, Michael D

2002-06-21

71

Geoengineering the Climate: Approaches to Counterbalancing Global Warming  

Microsoft Academic Search

For the past two hundred years, the inadvertent release of carbon dioxide and other radiatively active gases and aerosols, particularly as a result of combustion of fossil fuels and changes in land cover, have been contributing to global climate change. Global warming to date is approaching 1°C, and this is being accompanied by reduced sea ice, rising sea level, shifting

M. C. MacCracken

2005-01-01

72

Climatic warming increases isoprene emission from a subarctic heath  

Microsoft Academic Search

Emissions of isoprene, a reactive hydrocarbon, from Subarctic vegetation are not well documented. However, the Arctic is likely to experience the most pronounced effects of climatic warming, which may increase temperature-dependent isoprene emission. Here, we assessed isoprene emission from a Subarctic heath subjected to a 3-4 degrees C increase in air temperature and mountain birch (Betula pubescens ssp. czerepanovii) litter

Päivi Tiiva; Patrick Faubert; Anders Michelsen; Toini Holopainen; Jarmo K. Holopainen; Riikka Rinnan

2008-01-01

73

Seventh grade students' conceptions of global warming and climate change  

Microsoft Academic Search

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 administered to students. These data were

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

2009-01-01

74

Warming Up the Classroom Climate for Women.  

ERIC Educational Resources Information Center

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,…

Rosser, Sue V.

1989-01-01

75

African agriculture especially vulnerable to warming climate  

NASA Astrophysics Data System (ADS)

Malnourishment across Africa could jump 40% by 2050 due to climate change, according to the Africa Agriculture Status Report 2014 (AASR), released on 2 September. With temperatures predicted to rise 1.5°C-2.5°C by midcentury, African smallholder farms, which are generally run by one family, are more vulnerable than ever, the report finds.

Wendel, JoAnna

2014-09-01

76

Decision-making in Electricity Generation Based on Global Warming Potential and Life-cycle Assessment for Climate Change  

E-print Network

Global Warming Potential and Life-cycle Assessment for Climate Change"Global Warming Potential and Life-cycle Assessment for Climate Changeglobal warming potential (GWP) method. GWP is a method to compare the global climate change

Horvath, Arpad

2005-01-01

77

Geoengineering: Direct Mitigation of Climate Warming  

Microsoft Academic Search

\\u000a With the concentrations of atmospheric greenhouse gases (GHGs) rising to levels unprecedented in the current glacial epoch,\\u000a the earth’s climate system appears to be rapidly shifting into a warmer regime. Many in the international science and policy\\u000a communities fear that the fundamental changes in human behavior, and in the global economy, that will be required to meaningfully\\u000a reduce GHG emissions

Brooke L. Hemming; Gayle S. W. Hagler

78

Divergent tree growth response to recent climatic warming, Lake Clark National Park and Preserve, Alaska  

NASA Astrophysics Data System (ADS)

Many dendroclimatic studies have been conducted in Alaska to understand recent climate changes, identify past and current warming trends, and determine how climate change may influence ecosystems. Four new white spruce (Picea glauca [Moench] Voss) ring-width chronologies from four sites along a 30 kilometer north-south transect in the Lake Clark National Park and Preserve on the Alaskan Peninsula span a common interval from AD 1769 to 2003. Two sites show an internally consistent positive growth response to increasing April-July temperatures after 1950. The two other sites each contain two subpopulations showing varying growth responses. One subpopulation diverges from historical temperature data after 1950 and one shows increased growth consistent with warming or exceeds expected growth increases. The growth decline may be due to temperature-induced drought stress that acts on some trees. Unprecedented climatic changes are triggering diverse growth responses between and within study sites that may greatly complicate dendroclimatic reconstructions of past climate conditions.

Driscoll, William W.; Wiles, Gregory C.; D'Arrigo, Rosanne D.; Wilmking, Martin

2005-10-01

79

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

E-print Network

1 A brief history of climate � the northern seas from the Last Glacial Maximum to global warming maritime climate � from the Last Glacial Maximum through to the projected global warming of the 21st understanding of past, present, and projected future climate change in the northern seas region. Warm and cold

Drange, Helge

80

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

E-print Network

Permafrost, Lakes, and Climate-Warming Methane Feedback: What is the Worst We Can Expect? Xiang Gao://globalchange.mit.edu/ Printed on recycled paper #12;Permafrost, Lakes, and Climate-Warming Methane Feedback: What is the Worst Zhuang3 , and David Kicklighter4 Abstract Permafrost degradation is likely enhanced by climate warming

81

The effect of climate warming on the Qinghai-Tibet Highway, China  

Microsoft Academic Search

Climate warming greatly affected the environment in the Qinghai-Tibet plateau. Climate warming has led to the degradation of permafrost along the Qinghai-Tibet Highway (QTH). In such regions, the additional absorptive heat of the asphalt pavement has led to serious deterioration of the road. At the same time, climate warming will increase the depth of the active layer and will increase

Tong Changjiang; Wu Qingbai

1996-01-01

82

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

PubMed Central

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

Teplitsky, Celine; Millien, Virginie

2014-01-01

83

First tropical warm rain estimates could improve global climate models  

NSDL National Science Digital Library

This study breaks down the type of rainfall in the tropical zones. Microwave images and radar data from the Tropical Rainfall Measuring Mission were examined. It was found that approximately 72 percent of the total rain area and 31 percent of the total rain amount in the tropics comes from warm rain. The relationship between liquid water in a cloud and the rain rate was also measured. Results can be used in climate models to represent convection cycles and their role in global warming.

Lau, William; Wu, H. T.; Agu

84

Climate: large-scale warming is not urban.  

PubMed

Controversy has persisted over the influence of urban warming on reported large-scale surface-air temperature trends. Urban heat islands occur mainly at night and are reduced in windy conditions. Here we show that, globally, temperatures over land have risen as much on windy nights as on calm nights, indicating that the observed overall warming is not a consequence of urban development. PMID:15549087

Parker, David E

2004-11-18

85

Cold Climate, Warm Climates: How Can We Tell Past Temperatures?  

NSDL National Science Digital Library

This brief NASA article provides general information about paleoclimatology (the study of past climate). Focusing on ice core data and foraminifera (shelled marine microorganisms) in deep sea sediments, the article provides a summary of how paleoclimate can be inferred.

Schmidt, Gavin; Studies, Nasa G.

86

Warming Experiments Underpredict Plant Phenological Responses to Climate Change  

NASA Technical Reports Server (NTRS)

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.

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

87

Research Spotlight: Corals expanding poleward due to warming climate  

NASA Astrophysics Data System (ADS)

Corals are important organisms for ecosystems and are sensitive indicators of the effects of climate warming. While corals are bleaching and dying in tropical areas due to climate warming, a new study shows that in temperate areas they are expanding their range poleward as water temperatures increase. Yamano et al. used 80 years of records to study the range of corals around Japan. Sea surface temperatures have risen in these temperate areas during that time. They found that four of the nine species of coral they studied expanded their range northward since the 1930s, while none had its range shrink southward. The corals expanded northward as quickly as 14 kilometers per year. The study suggests that rapid modifications of temperate coastal ecosystems could be taking place. (Geophysical Research Letters, doi:10.1029/2010GL046474, 2011)

Tretkoff, Ernie

2011-04-01

88

Greenhouse Effect/Climate Change/Global Warming  

NSDL National Science Digital Library

The terms greenhouse effect, climate change, and global warming are often used interchangeably, yet they really refer to three separate and distinct processes. This activity examines all three and assesses whether Earth's atmosphere is getting warmer. Students will read two articles from the journal of Science that discuss the findings of the Intergovernmental Panel on Climate Change (IPCC) and investigate the bias of both groups of authors. This activity requires the use of two articles from the July 20, 2001 issue of the journal Science.

Fox, Chris

89

Climate and tourism in the Black Forest during the warm season  

NASA Astrophysics Data System (ADS)

Climate, climate change and tourism all interact. Part of the public discussion about climate change focusses on the tourism sector, with direct and indirect impacts being of equally high relevance. Climate and tourism are closely linked. Thus, climate is a very decisive factor in choices both of destination and of type of journey (active holidays, wellness, and city tours) in the tourism sector. However, whether choices about destinations or types of trip will alter with climate change is difficult to predict. Future climates can be simulated and projected, and the tendencies of climate parameters can be estimated using global and regional climate models. In this paper, the focus is on climate change in the mountainous regions of southwest Germany - the Black Forest. The Black Forest is one of the low mountain ranges where both winter and summer tourism are vulnerable to climate change due to its southern location; the strongest climatic changes are expected in areas covering the south and southwest of Germany. Moreover, as the choice of destination is highly dependent on good weather, a climatic assessment for tourism is essential. Thus, the aim of this study was to estimate climatic changes in mountainous regions during summer, especially for tourism and recreation. The assessment method was based on human-biometeorology as well as tourism-climatologic approaches. Regional climate simulations based on the regional climate model REMO were used for tourism-related climatic analyses. Emission scenarios A1B and B1 were considered for the time period 2021 to 2050, compared to the 30-year base period of 1971-2000, particularly for the warm period of the year, defined here as the months of March-November. In this study, we quantified the frequency, but not the means, of climate parameters. The study results show that global and regional warming is reflected in an increase in annual mean air temperature, especially in autumn. Changes in the spring show a slight negative trend, which is in line with the trend of a decrease in physiologically equivalent temperature as well as in thermal comfort conditions. Due to the rising air temperature, heat stress as well as sultry conditions are projected to become more frequent, affecting human health and recreation, especially at lower lying altitudes. The tops of the mountains and higher elevated areas still have the advantage of offering comfortable climatic conditions.

Endler, Christina; Matzarakis, Andreas

2011-03-01

90

Climate and tourism in the Black Forest during the warm season.  

PubMed

Climate, climate change and tourism all interact. Part of the public discussion about climate change focusses on the tourism sector, with direct and indirect impacts being of equally high relevance. Climate and tourism are closely linked. Thus, climate is a very decisive factor in choices both of destination and of type of journey (active holidays, wellness, and city tours) in the tourism sector. However, whether choices about destinations or types of trip will alter with climate change is difficult to predict. Future climates can be simulated and projected, and the tendencies of climate parameters can be estimated using global and regional climate models. In this paper, the focus is on climate change in the mountainous regions of southwest Germany - the Black Forest. The Black Forest is one of the low mountain ranges where both winter and summer tourism are vulnerable to climate change due to its southern location; the strongest climatic changes are expected in areas covering the south and southwest of Germany. Moreover, as the choice of destination is highly dependent on good weather, a climatic assessment for tourism is essential. Thus, the aim of this study was to estimate climatic changes in mountainous regions during summer, especially for tourism and recreation. The assessment method was based on human-biometeorology as well as tourism-climatologic approaches. Regional climate simulations based on the regional climate model REMO were used for tourism-related climatic analyses. Emission scenarios A1B and B1 were considered for the time period 2021 to 2050, compared to the 30-year base period of 1971-2000, particularly for the warm period of the year, defined here as the months of March-November. In this study, we quantified the frequency, but not the means, of climate parameters. The study results show that global and regional warming is reflected in an increase in annual mean air temperature, especially in autumn. Changes in the spring show a slight negative trend, which is in line with the trend of a decrease in physiologically equivalent temperature as well as in thermal comfort conditions. Due to the rising air temperature, heat stress as well as sultry conditions are projected to become more frequent, affecting human health and recreation, especially at lower lying altitudes. The tops of the mountains and higher elevated areas still have the advantage of offering comfortable climatic conditions. PMID:20490572

Endler, Christina; Matzarakis, Andreas

2011-03-01

91

Climate extremes and ecosystem productivity in global warming simulations  

NASA Astrophysics Data System (ADS)

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).

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

2013-12-01

92

Reductions in labour capacity from heat stress under climate warming  

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

93

Sensitivity of the seasonal snowcover to warming climate trends in a snow dominated semi- arid mountain basin  

NASA Astrophysics Data System (ADS)

Temperature of the western United States has increased by 1-2 C since 1950's. Over the last 45 years of record at the Reynolds Creek Experimental Watershed (RCEW), annual precipitation is unchanged, but these climate trends have altered the snowmelt dominated hydrologic cycle. More precipitation falls as rain, causing earlier snowmelt, earlier peak streamflow, reduced peak snow water equivalent, and reduced summer soil moisture and stream flow. Natural variation in weather and precipitation (wet-dry precipitation and warm-cold weather cycles) make it difficult to quantify the impacts of warming climate on hydrology. This study aims at understanding the differences in sensitivity of wet and dry snow seasons to the warming climate. For this purpose simulation of four snow seasons, representing range of precipitation (wet and dry) and temperature (warm and cold) conditions will be done using a spatially distributed snow energy and mass balance model (Isnobal). The four water years selected represent a range of conditions from early in the RCEW record to recent. The1984 water year (WY) was cold and very wet, the 1987 WY was cold and dry, the 2001 WY was warm and dry, and the 2006 WY was warm and wet. The sensitivity of the development and ablation of the seasonal snowcover to warming climate trends will be evaluated by altering temperature and humidity during the simulations. The 1984 adjusted simulation will use temperature and humidity conditions from 2006, 1987 will use temperature and humidity from 2001, 2001 will use temperature and humidity from 1987, and 2006 will use temperature and humidity from 1984. Comparison of the simulation results for the selected snow seasons under actual and adjusted forcing data would be helpful in understanding the impacts of climate warming on snow hydrology and the differences in sensitivity of wet and dry snow seasons to the warming climate.

Nayak, A.; Marks, D.; Chandler, D.; Winstral, A.

2007-12-01

94

Permafrost carbon-climate feedbacks accelerate global warming  

PubMed Central

Permafrost soils contain enormous amounts of organic carbon, which could act as a positive feedback to global climate change due to enhanced respiration rates with warming. We have used a terrestrial ecosystem model that includes permafrost carbon dynamics, inhibition of respiration in frozen soil layers, vertical mixing of soil carbon from surface to permafrost layers, and CH4 emissions from flooded areas, and which better matches new circumpolar inventories of soil carbon stocks, to explore the potential for carbon-climate feedbacks at high latitudes. Contrary to model results for the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4), when permafrost processes are included, terrestrial ecosystems north of 60°N could shift from being a sink to a source of CO2 by the end of the 21st century when forced by a Special Report on Emissions Scenarios (SRES) A2 climate change scenario. Between 1860 and 2100, the model response to combined CO2 fertilization and climate change changes from a sink of 68 Pg to a 27 + -7 Pg sink to 4 + -18 Pg source, depending on the processes and parameter values used. The integrated change in carbon due to climate change shifts from near zero, which is within the range of previous model estimates, to a climate-induced loss of carbon by ecosystems in the range of 25 + -3 to 85 + -16 Pg C, depending on processes included in the model, with a best estimate of a 62 + -7 Pg C loss. Methane emissions from high-latitude regions are calculated to increase from 34 Tg CH4/y to 41–70 Tg CH4/y, with increases due to CO2 fertilization, permafrost thaw, and warming-induced increased CH4 flux densities partially offset by a reduction in wetland extent. PMID:21852573

Koven, Charles D.; Ringeval, Bruno; Friedlingstein, Pierre; Ciais, Philippe; Cadule, Patricia; Khvorostyanov, Dmitry; Krinner, Gerhard; Tarnocai, Charles

2011-01-01

95

Heavy rainfall in future climate around the central Japan by pseudo global warming experiments  

NASA Astrophysics Data System (ADS)

The central part of Japan sometimes suffers from heavy rainfall derived by a typhoon. In 2000, a severe heavy rainfall attacked the central Japan. The maximum hourly precipitation in Aichi prefecture during this event was 114 mm, and daily precipitation 492 mm. On the other hand, it is reported that, in future climate, tropical cyclones (typhoons and hurricanes) will be stronger in IPCC AR4. In this study, variations in heavy rainfall around the central Japan are assessed by a pseudo global warming experiment using numerical weather prediction model. Based on the heavy rainfall event in 2000, pseudo global warming conditions are made from a reanalysis data and climate prediction in the 3rd phase of climate model intercomparison project (CMIP3), and simulations are made by the weather research forecasting model (WRF). The results of the control run of the heavy rainfall event in 2000 agree well with observed precipitation and same rainfall processes are found. In the pseudo global warming experiment using eight different CMIP3 output, five results show heavy rainfall around Aichi prefecture. Four results from the five heavy rainfalls show the larger maximum hourly precipitation, and the events continue longer than the control run. At the same time, using the same method, changes in precipitation characteristics around the central Japan are investigate for summer. The future climate conditions are obtained from dynamic downscaling by WRF using two pseudo global warming condition made with two CMIP3 projections (MPI ECHAM5 and CCCMA CGCM3.1 T47). The results show the opposite variation in future precipitation in the central Japan. In ECHAM5, summer precipitation increases in wide area, but the result with CCCMA shows decreasing precipitation especially in the Pacific side (see Figure). Such characteristics are found in the original CMIP3 output. Detail investigations of precipitation show that there are small variations in hourly precipitation in ECHAM5 and CCCMA. However, for three-hourly and six-hourly, ECHAM5 shows increasing precipitation in future but CCCMA decreasing. Those contradictions are thought to be caused by uncertainty of climate models used for making pseudo global warming conditions. Further study using many more CMIP3 model outputs is necessary for reliable assessment.; The difference in summer precipitation (June-August) between future and present climate around the central Japan. Left: result from pseudo global warming condition made with MPI ECHAM5. Right: result with CCCMA CGCM3.1 T47. The unit of color bar is mm.

Taniguchi, K.

2012-12-01

96

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

USGS Publications Warehouse

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. ?? 2010 The Authors. Journal of Fish Biology ?? 2010 The Fisheries Society of the British Isles.

Lyons, J.; Stewart, J.S.; Mitro, M.

2010-01-01

97

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

PubMed

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

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

98

Geographic variation in vulnerability to climate warming in a tropical Caribbean lizard  

E-print Network

and physiological capacity would change assuming climate warming of 3 °C over the next century. 3. The mean TeGeographic variation in vulnerability to climate warming in a tropical Caribbean lizard Alex R-scale analyses have predicted global patterns of vulnerability to warming, with tropical species at higher risk

Leal, Manuel S.

99

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

E-print Network

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 this: Global warming is a myth. It's all model predictions, nothing but simulations. Before you believe

Edwards, Paul N.

100

Can ozone depletion and global warming interact to produce rapid climate change?  

E-print Network

Can ozone depletion and global warming interact to produce rapid climate change? Dennis L. Hartmann of Climate Change (IPCC) assess- ment of the status of global warming, which reported that winter stratospheric ozone depletion and greenhouse warming are possible. These interactions may be responsible

Limpasuvan, Varavut

101

LETTER doi:10.1038/nature09407 Global metabolic impacts of recent climate warming  

E-print Network

LETTER doi:10.1038/nature09407 Global metabolic impacts of recent climate warming Michael E. Dillon and projected climate warming2,13,14 . Global warming is probably having profound and diverse effects phenology3,4 , community interactions5 , genetics3,6 and extinctions7 have been attributed to recent global

Huey, Raymond B.

102

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

103

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

104

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

SciTech Connect

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.

Raeisaenen, J.; Ruokolainen, L. [University of Helsinki (Finland). Division of Atmospheric Sciences and Geophysics

2008-09-30

105

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

E-print Network

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

Kreinovich, Vladik

106

A field facility to simulate climate warming and increased nutrient supply in shallow aquatic ecosystems.  

PubMed

Global warming and excess nitrogen deposition can exert strong impacts on aquatic populations, communities, and ecosystems. However, experimental data to establish clear cause-and-effect relationships in naturally complex field conditions are scarce in aquatic environments. Here, we describe the design and performance of a unique outdoor enclosure facility used to simulate warming, increased nitrogen supply, and both factors combined in a littoral freshwater wetland dominated by common reed, Phragmites australis. The experimental system effectively simulated a 2.8 °C climate warming scenario over an extended period, capturing the natural temperature variations in the wetland at diel and seasonal scales with only small deviations. Excess nitrogen supply enhanced nitrate concentrations especially in winter when it was associated with increased concentration of ammonium and dissolved organic carbon. Nitrogen also reduced dissolved oxygen concentrations, particularly in the summer. Importantly, by stimulating biological activity, warming enhanced the nitrogen uptake capacity of the wetland during the winter, emphasizing the need for multifactorial global change experiments that examine both warming and nitrogen loading in concert. Establishing similar experiments across broad environmental gradients holds great potential to provide robust assessments of the impacts of climate change on shallow aquatic ecosystems. PMID:23836092

Hines, Jes; Hammrich, Arne; Steiner, Daniel; Gessner, Mark O

2013-12-01

107

The Changing Geographic Distribution of Malaria with Global Climate Warming  

NSDL National Science Digital Library

This activity engages students in the analysis of climate data to first find areas in the southern United States that are now close to having conditions in which the malaria parasite and its mosquito hosts thrive and then attempt to forecast when areas might become climatically suitable.

Savina, Mary; Murray, Kendra; College, Carleton; Collection, Serc T.

108

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

E-print Network

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

Sukthankar, Gita Reese

109

The Compounding Effects of Tropical Deforestation and Greenhouse Warming on Climate  

Microsoft Academic Search

This study reports the first assessment of the compounding effects of land-use change and greenhouse gas warming effects on our understanding of projections of future climate. An AGCM simulation of the potential impacts of tropical deforestation and greenhouse warming on climate, employing a version of NCAR Community Climate Model (CCM1-Oz), is presented. The joint impacts of tropical deforestation and greenhouse

H. Zhang; A. Henderson-Sellers; K. McGuffie

2001-01-01

110

THE COMPOUNDING EFFECTS OF TROPICAL DEFORESTATION AND GREENHOUSE WARMING ON CLIMATE  

Microsoft Academic Search

This study reports the first assessment of the compounding effects of land-use change and greenhouse gas warming effects on our understanding of projections of future climate. An AGCM simulation of the potential impacts of tropical deforestation and greenhouse warming on climate, em- ploying a version of NCAR Community Climate Model (CCM1-Oz), is presented. The joint impacts of tropical deforestation and

H. ZHANG; A. HENDERSON-SELLERS; K. MCGUFFIE

2001-01-01

111

Microclimate impacts of passive warming methods in Antarctica: implications for climate change studies  

E-print Network

in descriptions of treatment effects. Keywords Antarctica � Climate change � Climate warming � Extreme eventREVIEW Microclimate impacts of passive warming methods in Antarctica: implications for climate change studies Stef Bokhorst � Ad Huiskes � Peter Convey � Brent J. Sinclair � Marc Lebouvier � Bart Van

Wall, Diana

112

Adaptability and adaptations of California's water supply system to dry climate warming  

E-print Network

-warm climate change increases the seasonal storage range of surface reservoirs and aquifers. Surface reservoir and impacts. Optimized operations of ground and surface water storage change significantly with climate. Dry peak storage usually occurs about a month earlier under dry-warm climate change. 1 Background

Pasternack, Gregory B.

113

Projection of Global Warming using an Empirical Model of Climate  

NASA Astrophysics Data System (ADS)

An empirical model of climate based on multiple linear regression of the century-long global surface temperature record is used to quantify the rise in global average temperature in 2053, the time CO2 reaches 560 ppm (2x pre-industrial) in the RCP 8.5 scenario. This rise in temperature is inherently uncertain due to the cantilevering of aerosol radiative forcing and climate feedback, coupled with the projection that aerosol radiative forcing will diminish in the coming decades due to air quality concerns. We show that, considering this cantilevering, the rise in global temperature at the time CO2 doubles will likely be between 1 and 2 degrees Celsius (relative to a 1961 to 1990 baseline). This empirically driven estimate of future warming is considerably less than projected by CMIP5 models.

Canty, Tim; Hope, Austin; Mascioli, Nora; Salawitch, Ross

2014-05-01

114

Vertical gradient of climate change and climate tourism conditions in the Black Forest.  

PubMed

Due to the public discussion about global and regional warming, the regional climate and the modified climate conditions are analyzed exemplarily for three different regions in the southern Black Forest (southwest Germany). The driving question behind the present study was how can tourism adapt to modified climate conditions and associated changes to the tourism potential in low mountain ranges. The tourism potential is predominately based on the attractiveness of natural resources being climate-sensitive. In this study, regional climate simulations (A1B) are analyzed by using the REMO model. To analyze the climatic tourism potential, the following thermal, physical and aesthetic parameters are considered for the time span 1961-2050: thermal comfort, heat and cold stress, sunshine, humid-warm conditions (sultriness), fog, precipitation, storm, and ski potential (snow cover). Frequency classes of these parameters expressed as a percentage are processed on a monthly scale. The results are presented in form of the Climate-Tourism-Information-Scheme (CTIS). Due to warmer temperatures, winters might shorten while summers might lengthen. The lowland might be more affected by heat and sultriness (e.g., Freiburg due to the effects of urban climate). To adapt to a changing climate and tourism, the awareness of both stakeholders and tourists as well as the adaptive capability are essential. PMID:19705164

Endler, Christina; Oehler, Karoline; Matzarakis, Andreas

2010-01-01

115

Vertical gradient of climate change and climate tourism conditions in the Black Forest  

NASA Astrophysics Data System (ADS)

Due to the public discussion about global and regional warming, the regional climate and the modified climate conditions are analyzed exemplarily for three different regions in the southern Black Forest (southwest Germany). The driving question behind the present study was how can tourism adapt to modified climate conditions and associated changes to the tourism potential in low mountain ranges. The tourism potential is predominately based on the attractiveness of natural resources being climate-sensitive. In this study, regional climate simulations (A1B) are analyzed by using the REMO model. To analyze the climatic tourism potential, the following thermal, physical and aesthetic parameters are considered for the time span 1961-2050: thermal comfort, heat and cold stress, sunshine, humid-warm conditions (sultriness), fog, precipitation, storm, and ski potential (snow cover). Frequency classes of these parameters expressed as a percentage are processed on a monthly scale. The results are presented in form of the Climate-Tourism-Information-Scheme (CTIS). Due to warmer temperatures, winters might shorten while summers might lengthen. The lowland might be more affected by heat and sultriness (e.g., Freiburg due to the effects of urban climate). To adapt to a changing climate and tourism, the awareness of both stakeholders and tourists as well as the adaptive capability are essential.

Endler, Christina; Oehler, Karoline; Matzarakis, Andreas

2010-01-01

116

Implications of global warming for the climate of African rainforests  

PubMed Central

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

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

2013-01-01

117

Climatic warming and increased malaria incidence in Rwanda.  

PubMed

Global climatic change is expected to increase the incidence of vector-borne diseases, especially malaria. This study assessed the contribution of climate to a malaria epidemic in Rwanda, focusing on the catchment area of one health centre where diagnosis was consistent and non-climatic variables well monitored. In late 1987 malaria incidence in the area increased by 337% over the 3 previous years. The increase was greatest in groups with little acquired immunity--children under 2 years (564%) and people in high-altitude areas (501%). Case-fatality rose significantly (relative risk = 4.85, p < 0.001). 1987 also saw record high temperatures and rainfall. An autoregressive equation including lagged effects of these two variables explained 80% of the variance in monthly malaria incidence. Temperature (especially mean minimum) predicted incidence best at higher altitudes where malaria had increased most. Empirically derived relations were consistent with the estimated generation time of the disease and with the known sensitivity of the plasmodium parasite to temperature. The patterns of climatic warming between day and night and among seasons will be critical to the effect on malaria. These findings are most relevant to regions near the altitude or latitude limits of the disease, where several epidemics have lately been reported. PMID:7907685

Loevinsohn, M E

1994-03-19

118

Impacts of climate warming on alpine glacier tourism and adaptive measures: A case study of Baishui Glacier No. 1 in Yulong Snow Mountain, Southwestern China  

Microsoft Academic Search

Alpine glaciers usually feature with best hydrothermal condition in mountain climate, and present beautiful glacier scenery,\\u000a various glacier landforms, rich biodiversity, and easier accessibility, compared with continental glaciers or ice sheets.\\u000a Nevertheless, Alpine glaciers are more sensitive to climate warming, and climate warming has seriously affected Alpine glaciers\\u000a and surrounding environment. The quality and attractiveness of Alpine glaciers to tourism

Shijin Wang; Yuanqing He; Xiaodong Song

2010-01-01

119

Estimating the potential for adaptation of corals to climate warming.  

PubMed

The persistence of tropical coral reefs is threatened by rapidly increasing climate warming, causing a functional breakdown of the obligate symbiosis between corals and their algal photosymbionts (Symbiodinium) through a process known as coral bleaching. Yet the potential of the coral-algal symbiosis to genetically adapt in an evolutionary sense to warming oceans is unknown. Using a quantitative genetics approach, we estimated the proportion of the variance in thermal tolerance traits that has a genetic basis (i.e. heritability) as a proxy for their adaptive potential in the widespread Indo-Pacific reef-building coral Acropora millepora. We chose two physiologically different populations that associate respectively with one thermo-tolerant (Symbiodinium clade D) and one less tolerant symbiont type (Symbiodinium C2). In both symbiont types, pulse amplitude modulated (PAM) fluorometry and high performance liquid chromatography (HPLC) analysis revealed significant heritabilities for traits related to both photosynthesis and photoprotective pigment profile. However, quantitative real-time polymerase chain reaction (qRT-PCR) assays showed a lack of heritability in both coral host populations for their own expression of fundamental stress genes. Coral colony growth, contributed to by both symbiotic partners, displayed heritability. High heritabilities for functional key traits of algal symbionts, along with their short clonal generation time and high population sizes allow for their rapid thermal adaptation. However, the low overall heritability of coral host traits, along with the corals' long generation time, raise concern about the timely adaptation of the coral-algal symbiosis in the face of continued rapid climate warming. PMID:20305781

Császár, Nikolaus B M; Ralph, Peter J; Frankham, Richard; Berkelmans, Ray; van Oppen, Madeleine J H

2010-01-01

120

Anticipated impacts of climate warming on ecosystems in Interior Alaska  

NASA Astrophysics Data System (ADS)

Future climate scenarios predict a roughly 5 degree increase in mean annual air temperatures for the Alaskan Interior over the next 80 years. This is expected to be enough to initiate permafrost degradation in Interior Alaska which could lead to widespread thermokarst and talik development and potentially a thicker seasonally thawed (active) layer. These changes could dramatically affect hydrology, ground surface topography and vegetation. Forecasting ecological responses to climate warming is complicated by many factors including variations in soil type, precipitation, surface and ground water hydrology, vegetation, slope, aspect, fire prevalence, and the thermal state of permafrost. We are making field measurements and time series repeat imagery at upland and lowland landscapes to determine where and what ecosystem processes may be most susceptible for rapid or unpredictable changes with climate warming or changing land use activities. By integrating existing cryospheric (permafrost and snow), hydrologic and vegetation succession modeling capabilities we hope to enhance our ability to predict how climate change and other stressors may affect ecosystem dynamics and fire susceptibility. We will include the effects of non-climate related anthropogenic stressors like changes in land use activities and infrastructure development. Numerous electrical resistivity geophysical measurements have been made across a variety of landscapes to investigate how vegetation, soils, and land use relates to permafrost distribution. Our project results will be synthesized into a spatially-explicit decision support system to assist with land use management decision-making for Interior Alaska. This Geographic Information Systems (GIS)-based tool is being developed through a combination of field work and modeling. We will identify challenges for management activities given the projected ecosystem response to anticipated climate change by the end-of-the century. This presentation will summarize the first year of research results from this multi-agency, multidisciplinary research project. The project team includes more than 20 researchers, collaborators, students and land users that are actively working on this research program. Results will include geophysical measurements of surface soils and permafrost, the first hydrologic measurements across the Tanana Flats lowlands and the glacier fed Jarvis Creek, repeat imagery of landscapes exhibiting change over time, vegetation mapping, and hydrologic and ecosystem simulations.

Douglas, T. A.; Liljedahl, A. K.; Astley, B. N.; Downer, C. W.; Jorgenson, T. T.; Bagley, C.; Burks-Copes, K.

2011-12-01

121

Multisectoral climate impact hotspots in a warming world  

PubMed Central

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

Piontek, Franziska; Muller, Christoph; Pugh, Thomas A. M.; Clark, Douglas B.; Deryng, Delphine; Elliott, Joshua; Colon Gonzalez, Felipe de Jesus; Florke, 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

122

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

NASA Astrophysics Data System (ADS)

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

Rheinheimer, David Emmanuel

123

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

PubMed Central

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

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

2012-01-01

124

Climate Response of the Equatorial Pacific to Global Warming PEDRO N. DINEZIO  

E-print Network

Climate Response of the Equatorial Pacific to Global Warming PEDRO N. DINEZIO Cooperative Institute balance the heating over the warm pool, while increased cooling by ocean vertical heat transport balances the warming over the cold tongue. This increased cooling by vertical ocean heat transport arises from

125

Why are climate models reproducing the observed global surface warming so well?  

E-print Network

Why are climate models reproducing the observed global surface warming so well? Reto Knutti1 global surface warming so well?, Geophys. Res. Lett., 35, L18704, doi:10.1029/ 2008GL034932. 1 models reproduce the observed surface warming better than one would expect given the uncertainties

Fischlin, Andreas

126

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

PubMed

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

Zeng, Biao; Yang, Tai-Bao

2008-09-01

127

Geoengineering the Climate: Approaches to Counterbalancing Global Warming  

NASA Astrophysics Data System (ADS)

For the past two hundred years, the inadvertent release of carbon dioxide and other radiatively active gases and aerosols, particularly as a result of combustion of fossil fuels and changes in land cover, have been contributing to global climate change. Global warming to date is approaching 1°C, and this is being accompanied by reduced sea ice, rising sea level, shifting ecosystems and more. Rather than sharply curtailing use of fossil fuels in order to reduce CO2 emissions and eventually eliminate the net human influence on global climate, a number of approaches have been suggested that are intended to advertently modify the climate in a manner to counter-balance the warming influence of greenhouse gas emissions. One general type of approach is carbon sequestration, which focuses on capturing the CO2 and then sequestering it underground or in the ocean. This can be done at the source of emission, by pulling the CO2 out of the atmosphere through some chemical process, or by enhancing the natural processes that remove CO2 from the atmosphere, for example by fertilizing the oceans with iron. A second general approach to geoengineering the climate is to lower the warming influence of the incoming solar radiation by an amount equivalent to the energy captured by the CO2-induced enhancement of the greenhouse effect. Proposals have been made to do this by locating a deflector at the Earth-Sun Lagrange point, lofting many thousands of near-Earth mirrors, injecting aerosols into the stratosphere, or by increasing the surface albedo. A third general approach is to alter natural Earth system processes in ways that would counterbalance the effects of the warming. Among suggested approaches are constructing dams to block various ocean passages, oceanic films to limit evaporation and water vapor feedback, and even, at small scale, to insulate mountain glaciers to prevent melting. Each of these approaches has its advantages, ranging from simplicity to reversibility, and disadvantages, ranging from costs for implementation to associated inadvertent negative environmental consequences. Unless implemented as only a bridging effort, geoengineering would require diversion of substantial, and even growing, resources from the effort to move away from reliance on fossil fuels. Because the lifetime of the excess CO2 in the atmosphere is so long, such efforts would generally need to be maintained for centuries by future generations to avoid a relatively rapid increase in global average temperature, even after emissions of CO2 had eventually been halted. In that such approaches are also fraught with uncertainties, there has been very little study of the details of how such approaches might be pursued and of their overall advertent and inadvertent consequences, leaving the area open to ongoing consideration of sometimes rather speculative possibilities.

MacCracken, M. C.

2005-12-01

128

Territorial Manifestations of the Economical Influence Areas of Global Warming and Climate Change  

Microsoft Academic Search

Economic space is structured by the relationship between the anthropogenic and economic factors, with a dynamical evolution defined by the financial flows around the world and technology evolution. The global warming and the climate change are two different processes associated on the planet, due to different etiologies: the global warming is produced principally by anthropogenic effects, whereas the climate change

Y. G. Garcia Lopez; J. A. Perez-Peraza; V. M. Velasco Herrera

2007-01-01

129

A mechanism for landocean contrasts in global monsoon trends in a warming climate  

E-print Network

A mechanism for land­ocean contrasts in global monsoon trends in a warming climate J. Fasullo of the global monsoon record involves reported decreases in rainfall over land during an era in which the global in the monsoons in a warming climate while bolstering the concept of the global monsoon in the context of shared

Fasullo, John

130

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

E-print Network

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. Climatology--History. 3. Meteorology--History. 4. Climatology--Technological innovation. 5. Global temperature

131

Climatic warming increases voltinism in European butterflies and moths  

PubMed Central

Climate change is altering geographical ranges, population dynamics and phenologies of many organisms. For ectotherms, increased ambient temperatures frequently have direct consequences for metabolic rates, activity patterns and developmental rates. Consequently, in many insect species both an earlier beginning and prolongation of seasonal duration occurred in parallel with recent global warming. However, from an ecological and evolutionary perspective, the number of generations (voltinism) and investment into each generation may be even more important than seasonality, since an additional generation per unit time may accelerate population growth or adaptation. Using a dataset extending back to the mid-nineteenth century, I report changes in the voltinism of butterfly and moth species of Central Europe. A significant proportion of 263 multi-voltine species showed augmented frequency of second and subsequent generations relative to the first generation in a warm period since 1980, and 44 species even increased the number of generations after 1980. Expected ecological consequences are diverse. Since multi-voltinism has been linked to insect outbreaks they include an increase in the abundance of herbivorous pests of agriculture and forestry. However, disruption of the developmental synchrony associated with multi-voltinism and host plant phenology may also reduce fitness, potentially having unexpected consequences for species of conservation concern. The ability of species to adapt evolutionarily to a changing environment may be facilitated by increased voltinism. PMID:20031988

Altermatt, Florian

2010-01-01

132

Declining ocean anoxia in a warming climate (Invited)  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

133

Response of global warming on regional climate change over Korea: An experiment with the MM5 model  

Microsoft Academic Search

This study is to investigate changes in regional surface climate arising from global warming with MM5 downscaling simulation for the period 1971-2100. The main focus is on the drought conditions over Korea. Palmer Drought Severity Index (PDSI) is utilized as a measure of drought severity. The important findings show the increase of surface air temperature by 6°C and precipitation by

Kyung-On Boo; Won-Tae Kwon; Jai-Ho Oh; Hee-Jeong Baek

2004-01-01

134

Response of global warming on regional climate change over Korea: An experiment with the MM5 model  

Microsoft Academic Search

This study is to investigate changes in regional surface climate arising from global warming with MM5 downscaling simulation for the period 1971–2100. The main focus is on the drought conditions over Korea. Palmer Drought Severity Index (PDSI) is utilized as a measure of drought severity. The important findings show the increase of surface air temperature by 6°C and precipitation by

Kyung-On Boo; Won-Tae Kwon; Jai-Ho Oh; Hee-Jeong Baek

2004-01-01

135

Global warming and climate change in Amazonia: Climate-vegetation feedback and impacts on water resources  

NASA Astrophysics Data System (ADS)

This chapter constitutes an updated review of long-term climate variability and change in the Amazon region, based on observational data spanning more than 50 years of records and on climate-change modeling studies. We start with the early experiments on Amazon deforestation in the late 1970s, and the evolution of these experiments to the latest studies on greenhouse gases emission scenarios and land use changes until the end of the twenty-first century. The "Amazon dieback" simulated by the HadCM3 model occurs after a "tipping point" of CO2 concentration and warming. Experiments on Amazon deforestation and change of climate suggest that once a critical deforestation threshold (or tipping point) of 40-50% forest loss is reached in eastern Amazonia, climate would change in a way which is dangerous for the remaining forest. This may favor a collapse of the tropical forest, with a substitution of the forest by savanna-type vegetation. The concept of "dangerous climate change," as a climate change, which induces positive feedback, which accelerate the change, is strongly linked to the occurrence of tipping points, and it can be explained as the presence of feedback between climate change and the carbon cycle, particularly involving a weakening of the current terrestrial carbon sink and a possible reversal from a sink (as in present climate) to a source by the year 2050. We must, therefore, currently consider the drying simulated by the Hadley Centre model(s) as having a finite probability under global warming, with a potentially enormous impact, but with some degree of uncertainty.

Marengo, José; Nobre, Carlos A.; Betts, Richard A.; Cox, Peter M.; Sampaio, Gilvan; Salazar, Luis

136

Climate warming and estuarine and marine coastal ecosystems  

SciTech Connect

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.

Kennedy, V.S. [Univ. of Maryland Center for Environmental and Estuarine Studies, Cambridge, MD (United States). Horn Point Environmental Lab.

1994-12-31

137

Climate Change over the Equatorial Indo-Pacific in Global Warming* CHIE IHARA, YOCHANAN KUSHNIR, AND MARK A. CANE  

E-print Network

Climate Change over the Equatorial Indo-Pacific in Global Warming* CHIE IHARA, YOCHANAN KUSHNIR to global warming is investigated using model outputs submitted to the Intergovernmental Panel on Climate equatorial Indian Ocean warm more than the SSTs in the eastern equatorial Indian Ocean under global warming

138

Global warming vs. climate change, taxes vs. prices: Does word choice matter?  

Microsoft Academic Search

Does “climate change” seem like a less serious problem than “global warming” to Americans and Europeans? Does describing the\\u000a costs of climate change mitigation in terms of “higher taxes” instead of “higher prices” reduce public support for such efforts?\\u000a In an experiment embedded in an American national survey, respondents were randomly assigned to rate the seriousness of “global\\u000a warming,” “climate

Ana Villar; Jon A. Krosnick

2011-01-01

139

Energetic contribution potential of building-integrated photovoltaics on airports in warm climates  

SciTech Connect

Especially in warm climates, a considerable fraction of the electricity demand in commercial buildings is due to the intensive use of air-conditioning systems. Airport buildings in sunny and warm regions present a perfect match between energy demand and solar resource availability. Airport buildings are also typically large and horizontal, isolated and free of shading, and have a great potential for the integration of solar photovoltaic (PV) systems. In this work, we assess the potential impact in energy demand reduction at the Florianopolis International Airport in Brazil (27 S, 48 W) with the use of building-integrated photovoltaic (BIPV) systems. We analyse the building's hourly energy consumption and solar irradiation data, to assess the match between energy demand and potential generation, and we estimate the PV power necessary to supply both the total amount and fractions of the annual energy demand. Our results show that the integration of PV systems on airport buildings in warm climates can supply the entire electric power consumption of an airport complex, in line with the general concept of a zero-energy building (ZEB). (author)

Ruether, Ricardo [LabEEE - Laboratorio de Eficiencia Energetica em Edificacoes, UFSC - Universidade Federal de Santa Catarina, Caixa Postal 476, Florianopolis, SC 88040-900 (Brazil); LABSOLAR - Laboratorio de Energia Solar, UFSC - Universidade Federal de Santa Catarina, Caixa Postal 476, Florianopolis, SC 88040-900 (Brazil); Braun, Priscila [LabEEE - Laboratorio de Eficiencia Energetica em Edificacoes, UFSC - Universidade Federal de Santa Catarina, Caixa Postal 476, Florianopolis, SC 88040-900 (Brazil)

2009-10-15

140

Disparity in elevational shifts of European trees in response to recent climate warming.  

PubMed

Predicting climate-driven changes in plant distribution is crucial for biodiversity conservation and management under recent climate change. Climate warming is expected to induce movement of species upslope and towards higher latitudes. However, the mechanisms and physiological processes behind the altitudinal and latitudinal distribution range of a tree species are complex and depend on each tree species features and vary over ontogenetic stages. We investigated the altitudinal distribution differences between juvenile and adult individuals of seven major European tree species along elevational transects covering a wide latitudinal range from southern Spain (37°N) to northern Sweden (67°N). By comparing juvenile and adult distributions (shifts on the optimum position and the range limits) we assessed the response of species to present climate conditions in relation to previous conditions that prevailed when adults were established. Mean temperature increased by 0.86 °C on average at our sites during the last decade compared with previous 30-year period. Only one of the species studied, Abies alba, matched the expected predictions under the observed warming, with a maximum abundance of juveniles at higher altitudes than adults. Three species, Fagus sylvatica, Picea abies and Pinus sylvestris, showed an opposite pattern while for other three species, such as Quercus ilex, Acer pseudoplatanus and Q. petraea, we were no able to detect changes in distribution. These findings are in contrast with theoretical predictions and show that tree responses to climate change are complex and are obscured not only by other environmental factors but also by internal processes related to ontogeny and demography. PMID:23572443

Rabasa, Sonia G; Granda, Elena; Benavides, Raquel; Kunstler, Georges; Espelta, Josep M; Ogaya, Romá; Peñuelas, Josep; Scherer-Lorenzen, Michael; Gil, Wojciech; Grodzki, Wojciech; Ambrozy, Slawomir; Bergh, Johan; Hódar, José A; Zamora, Regino; Valladares, Fernando

2013-08-01

141

Modeling the impacts of two bark beetle species under a warming climate in the southwestern USA: Ecological and economic consequences.  

PubMed

Predicted climate warming is expected to have profound effects on bark beetle population dynamics in the southwestern United States. Temperature-mediated effects may include increases in developmental rates, generations per year, and changes in habitat suitability. As a result, the impacts of Dendroctonus frontalis and Dendroctonus mexicanus on forest resources are likely subject to amplification. To assess the implications of such change, we evaluated the generations per year of these species under three climate scenarios using a degree-day development model. We also assessed economic impacts of increased beetle outbreaks in terms of the costs of application of preventative silvicultural treatments and potential economic revenues forgone. Across the southwestern USA, the potential number of beetle generations per year ranged from 1-3+ under historical climate, an increase of 2-4+ under the minimal warming scenario and 3-5+ under the greatest warming scenario. Economic benefits of applying basal area reduction treatments to reduce forest susceptibility to beetle outbreaks ranged from $7.75/ha (NM) to $95.69/ha (AZ) under historical conditions, and $47.96/ha (NM) to $174.58/ha (AZ) under simulated severe drought conditions. Basal area reduction treatments that reduce forest susceptibility to beetle outbreak result in higher net present values than no action scenarios. Coupled with other deleterious consequences associated with beetle outbreaks, such as increased wildfires, the results suggest that forest thinning treatments play a useful role in a period of climate warming. PMID:19680717

Waring, Kristen M; Reboletti, Danielle M; Mork, Lauren A; Huang, Ching-Hsun; Hofstetter, Richard W; Garcia, Amanda M; Fulé, Peter Z; Davis, T Seth

2009-10-01

142

The toxicology of climate change: Environmental contaminants in a warming world  

Microsoft Academic Search

Climate change induced by anthropogenic warming of the earth's atmosphere is a daunting problem. This review examines one of the consequences of climate change that has only recently attracted attention: namely, the effects of climate change on the environmental distribution and toxicity of chemical pollutants. A review was undertaken of the scientific literature (original research articles, reviews, government and intergovernmental

Pamela D. Noyes; Matthew K. McElwee; Hilary D. Miller; Bryan W. Clark; Lindsey A. Van Tiem; Kia C. Walcott; Kyle N. Erwin; Edward D. Levin

2009-01-01

143

Soils Cool as Climate Warms in the Great Lakes Region: 19512000  

E-print Network

Soils Cool as Climate Warms in the Great Lakes Region: 1951­2000 S. A. Isard,* R. J. Schaetzl Lakes region. Key Words: climate, global change, Great Lakes region, lake-effect snow, soil temperatures. H istorical air temperature data series indicate that the climate of the Great Lakes region has been

Schaetzl, Randall

144

Warm Eocene climate enhanced petroleum generation from Cretaceous source rocks: A potential climate feedback mechanism?  

NASA Astrophysics Data System (ADS)

Earth surface temperatures, including in the deep sea increased by 5-10°C from the late Paleocene ca. 58 Myr ago to the Early Eocene Climatic Optimum (EECO) centered at about 51 Myr ago. A large (˜2.5‰) drop in ?13C of carbonate spans much of this interval. This suggests a long-term increase in the net flux of 13C-depleted carbon to the ocean and atmosphere that is difficult to explain by changes in surficial carbon cycling alone. We reveal a relationship between surface temperature increase and increased petroleum generation in sedimentary basins operating on 100 kyr to Myr time scales. We propose that early Eocene warming has led to a synchronization of periods of maximum petroleum generation and enhanced generation in otherwise unproductive basins through extension of the volume of source rock within the oil and gas window across hundreds of sedimentary basins globally. Modelling the thermal evolution of four sedimentary basins in the southwest Pacific predicted an up to 50% increase in petroleum generation that would have significantly increased leakage of light hydrocarbons and oil degeneration products into the atmosphere. Extrapolating our modelling results to hundreds of sedimentary basins worldwide suggests that globally increased leakage could have caused a climate feedback effect, driving or enhancing early Eocene climate warming.

Kroeger, K. F.; Funnell, R. H.

2012-02-01

145

The tundra warms and grows The effects of climate change on tundra  

E-print Network

ECOLOGY The tundra warms and grows The effects of climate change on tundra in the high Arctic on the tundra of Ellesmere Island in Nunavut, Canada, show an ecosystem `in transition'. Temperatures have risen

146

Response of ocean ecosystems to climate warming J. L. Sarmiento,1  

E-print Network

the ocean biological response to climate warming between the beginning of the industrial revolution and 2050 production algorithms. We also show results for the period between the industrial revolution and 2050

Kleypas, Joanie

147

Impacts of climate change in a global hotspot for temperate marine biodiversity and ocean warming  

Microsoft Academic Search

Temperate Australia is a global hotspot for marine biodiversity and its waters have experienced well-above global average rates of ocean warming. We review the observed impacts of climate change (e.g. warming, ocean acidification, changes in storm patterns) on subtidal temperate coasts in Australia and assess how these systems are likely to respond to further change. Observed impacts are region specific

Thomas Wernberg; Bayden D. Russell; Pippa J. Moore; Scott D. Ling; Daniel A. Smale; Alex Campbell; Melinda A. Coleman; Peter D. Steinberg; Gary A. Kendrick; Sean D. Connell

2011-01-01

148

A latitudinal gradient in tree growth response to climate warming in the Siberian taiga  

E-print Network

A latitudinal gradient in tree growth response to climate warming in the Siberian taiga A N D R E Siberian taiga species, Larix cajanderi, Picea obovata, and Pinus sylvestris, across a latitudinal gradient that increased productivity with warming is likely only in the northern reaches of the Siberian taiga

Wagner, Diane

149

Limnological and ecological sensitivity of Rwenzori mountain lakes to climate warming  

Microsoft Academic Search

An increasing number of studies forecast that anthropogenic climate change poses serious consequences for the biodiversity\\u000a and ecosystem functioning of high-elevation mountain lakes, through a series of both direct and indirect effects. The impacts\\u000a of future climate warming on alpine ecosystems are of particular concern, given that warming is expected to be most pronounced\\u000a at high elevations around the globe.

Hilde Eggermont; Dirk Verschuren; Leen Audenaert; Luc Lens; James Russell; Gerrit Klaassen; Oliver Heiri

2010-01-01

150

Testing paradigms of ecosystem change under climate warming in Antarctica.  

PubMed

Antarctic marine ecosystems have undergone significant changes as a result of human activities in the past and are now responding in varied and often complicated ways to climate change impacts. Recent years have seen the emergence of large-scale mechanistic explanations-or "paradigms of change"-that attempt to synthesize our understanding of past and current changes. In many cases, these paradigms are based on observations that are spatially and temporally patchy. The West Antarctic Peninsula (WAP), one of Earth's most rapidly changing regions, has been an area of particular research focus. A recently proposed mechanistic explanation for observed changes in the WAP region relates changes in penguin populations to variability in krill biomass and regional warming. While this scheme is attractive for its simplicity and chronology, it may not account for complex spatio-temporal processes that drive ecosystem dynamics in the region. It might also be difficult to apply to other Antarctic regions that are experiencing some, though not all, of the changes documented for the WAP. We use qualitative network models of differing levels of complexity to test paradigms of change for the WAP ecosystem. Importantly, our approach captures the emergent effects of feedback processes in complex ecological networks and provides a means to identify and incorporate uncertain linkages between network elements. Our findings highlight key areas of uncertainty in the drivers of documented trends, and suggest that a greater level of model complexity is needed in devising explanations for ecosystem change in the Southern Ocean. We suggest that our network approach to evaluating a recent and widely cited paradigm of change for the Antarctic region could be broadly applied in hypothesis testing for other regions and research fields. PMID:23405116

Melbourne-Thomas, Jessica; Constable, Andrew; Wotherspoon, Simon; Raymond, Ben

2013-01-01

151

Impacts of climate extremes on gross primary production under global warming  

NASA Astrophysics Data System (ADS)

The impacts of historical droughts and heat-waves on ecosystems are often considered indicative of future global warming impacts, under the assumption that water stress sets in above a fixed high temperature threshold. Historical and future (RCP8.5) Earth system model (ESM) climate projections were analyzed in this study to illustrate changes in the temperatures for onset of water stress under global warming. The ESMs examined here predict sharp declines in gross primary production (GPP) at warm temperature extremes in historical climates, similar to the observed correlations between GPP and temperature during historical heat-waves and droughts. However, soil moisture increases at the warm end of the temperature range, and the temperature at which soil moisture declines with temperature shifts to a higher temperature. The temperature for onset of water stress thus increases under global warming and is associated with a shift in the temperature for maximum GPP to warmer temperatures. Despite the shift in this local temperature optimum, the impacts of warm extremes on GPP are approximately invariant when extremes are defined relative to the optimal temperature within each climate period. The GPP sensitivity to these relative temperature extremes therefore remains similar between future and present climates, suggesting that the heat- and drought-induced GPP reductions seen recently can be expected to be similar in the future, and may be underestimates of future impacts given model projections of increased frequency and persistence of heat-waves and droughts. The local temperature optimum can be understood as the temperature at which the combination of water stress and light limitations is minimized, and this concept gives insights into how GPP responds to climate extremes in both historical and future climate periods. Both cold (temperature and light-limited) and warm (water-limited) relative temperature extremes become more persistent in future climate projections, and the time taken to return to locally optimal climates for GPP following climate extremes increases by more than 25% over many land regions.

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

2014-09-01

152

Climate variability, warming and ice melt on the Antarctic Peninsula over the last millennium (Invited)  

NASA Astrophysics Data System (ADS)

The Antarctic Peninsula has experienced rapid warming over the past 50 years, which has led to extensive summer ice melt, the collapse of ice shelves and the acceleration of glacial outflow. But the short observational records of Antarctic climate don't allow for an understanding of how unusual the recent conditions may be. We present reconstructions of temperature and melt history since 1000 AD from a highly resolved ice core record from James Ross Island on the northeastern Antarctic Peninsula. The spatial pattern of temperature variability across networks of palaeoclimate reconstructions demonstrates that the Southern Annular Mode (SAM) has been an important driver of Antarctic Peninsula climate variability over a range of time scales. Rapid warming of the Antarctic Peninsula since the mid-20th century is consistent with strengthening of the SAM by a combination of greenhouse and later ozone forcing. The rare reconstruction of summer melting, from visible melt layers in the ice core, demonstrates the non-linear response of ice melt to increasing summer temperatures. Melting in the region is now more intense than at any other time over the last 1000 years and suggests that the Antarctic Peninsula is now particularly susceptible to rapid increases in ice loss in response to relatively small increases in mean temperature.

Abram, N.; Mulvaney, R.; Wolff, E. W.; Triest, J.; Kipfstuhl, S.; Trusel, L. D.; Vimeux, F.; Fleet, L.; Arrowsmith, C.

2013-12-01

153

CLIMATE RESPONSE OF THE EQUATORIAL PACIFIC TO GLOBAL WARMING  

Microsoft Academic Search

The climate response of the equatorial Pacific to increased greenhouse gases is investigated using numerical experiments from 11 climate models participating in the Intergovernmental Panel on Climate Change's Fourth Assessment Report. Multimodelmean climate responsestoCO2 doubling are identified and related to changes in the heat budget of the surface layer. Weaker ocean surface currents driven by a slowing down of the

Pedro N. DiNezio; AMY C. CLEMENT; GABRIEL A. VECCHI; BRIAN J. SODEN; BENJAMIN P. KIRTMAN; SANG-KI LEE

2008-01-01

154

Effects of climate warming on polar bears: a review of the evidence.  

PubMed

Climate warming is causing unidirectional changes to annual patterns of sea ice distribution, structure, and freeze-up. We summarize evidence that documents how loss of sea ice, the primary habitat of polar bears (Ursus maritimus), negatively affects their long-term survival. To maintain viable subpopulations, polar bears depend on sea ice as a platform from which to hunt seals for long enough each year to accumulate sufficient energy (fat) to survive periods when seals are unavailable. Less time to access to prey, because of progressively earlier breakup in spring, when newly weaned ringed seal (Pusa hispida) young are available, results in longer periods of fasting, lower body condition, decreased access to denning areas, fewer and smaller cubs, lower survival of cubs as well as bears of other age classes and, finally, subpopulation decline toward eventual extirpation. The chronology of climate-driven changes will vary between subpopulations, with quantifiable negative effects being documented first in the more southerly subpopulations, such as those in Hudson Bay or the southern Beaufort Sea. As the bears' body condition declines, more seek alternate food resources so the frequency of conflicts between bears and humans increases. In the most northerly areas, thick multiyear ice, through which little light penetrates to stimulate biological growth on the underside, will be replaced by annual ice, which facilitates greater productivity and may create habitat more favorable to polar bears over continental shelf areas in the short term. If the climate continues to warm and eliminate sea ice as predicted, polar bears will largely disappear from the southern portions of their range by mid-century. They may persist in the northern Canadian Arctic Islands and northern Greenland for the foreseeable future, but their long-term viability, with a much reduced global population size in a remnant of their former range, is uncertain. PMID:24501049

Stirling, Ian; Derocher, Andrew E

2012-09-01

155

Cold climate bioventing with soil warming in Alaska  

SciTech Connect

In the heart of Alaska, a 3-year field study was conducted of bioventing in conjunction with several soil warming methods. The contamination was JP-4 jet fuel. The soil warming methods evaluated, chosen for their apparent low cost, were (1) application of warm water at a low rate, (2) enhanced solar warming by covering the surface with clear plastic in the summer and covering the surface with insulation in the winter, and (3) buried heat pipe. The warm water and buried heat tape methods performed best, maintaining summer-like 10 to 20 C temperatures in the test plots year round, compared to the temperature of the unheated control plot, which dipped to {minus}1 C in the winter. The solar/insulation warming method showed a modest improvement in temperature over the unheated control test plot. The annual average temperatures of the warm water, heat tape, solar, and control plots were 16.9, 14.5, 6.1, and 3.5 C, respectively. The biodegradation rates, measured by in situ respirometry, were higher in plots with higher temperatures and followed the Arrhenius relationship. Despite the low temperature, significant biodegradation was observed in the unheated plot during the winter.

Sayles, G.D.; Brenner, R.C. [Environmental Protection Agency, Cincinnati, OH (United States); Leeson, A.; Hinchee, R.E. [Battelle Columbus, OH (United States); Vogel, C.M. [Air Force, Tyndall AFB, FL (United States). Environics Directorate; Miller, R.N. [Air Force, Brooks AFB, TX (United States)

1995-12-31

156

Climate Warming, Marine Protected Areas and the Ocean-Scale Integrity of Coral Reef Ecosystems  

Microsoft Academic Search

Coral reefs have emerged as one of the ecosystems most vulnerable to climate variation and change. While the contribution of a warming climate to the loss of live coral cover has been well documented across large spatial and temporal scales, the associated effects on fish have not. Here, we respond to recent and repeated calls to assess the importance of

Nicholas A. J. Graham; Tim R. McClanahan; M. Aaron MacNeil; Shaun K. Wilson; Nicholas V. C. Polunin; Simon Jennings; Pascale Chabanet; Susan Clark; Mark D. Spalding; Yves Letourneur; Lionel Bigot; René Galzin; Marcus C. Öhman; Kajsa C. Garpe; Alasdair J. Edwards; Charles R. C. Sheppard

2008-01-01

157

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

E-print Network

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

Mahowald, Natalie

158

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

Microsoft Academic Search

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

Gowri Koneswaran; Danielle Nierenberg

2008-01-01

159

DEVELOPMENT OF A MODEL FOR ESTIMATING THE SENSITIVITY OF CANADIAN PEATLANDS TO CLIMATE WARMING  

Microsoft Academic Search

Under current scenarios of increasing greenhouse gases, the expected increases in global temperatures have the potential to affect, in many areas, the peat- lands that now cover 14 % of the soil area of Canada. A model for estimating peatland sen- sitivity to climate warming was developed using published information on the current state of climate, vegetation, and permafrost together

Inez M. KETTLES; Charles TARNOCAI

160

Climate change drives warming in the Hudson River Estuary, New York (USA).  

PubMed

Estuaries may be subject to warming due to global climate change but few studies have considered the drivers or seasonality of warming empirically. We analyzed temperature trends and rates of temperature change over time for the Hudson River estuary using long-term data, mainly from daily measures taken at the Poughkeepsie Water Treatment Facility. This temperature record is among the longest in the world for a river or estuary. The Hudson River has warmed 0.945 °C since 1946. Many of the warmest years in the record occurred in the last 16 years. A seasonal analysis of trends indicated significant warming for the months of April through August. The warming of the Hudson is primarily related to increasing air temperature. Increasing freshwater discharge into the estuary has not mitigated the warming trend. PMID:21720614

Seekell, David A; Pace, Michael L

2011-08-01

161

REGIONAL CLIMATE CHANGE SCENARIOS UNDER GLOBAL WARMING IN KAZAKHSTAN  

Microsoft Academic Search

The aim of this paper is to report on the development of regional climate change scenarios for Kazakhstan as the result of increasing of CO2 concentration in the global atmosphere. These scenarios are used in the assessment of climate change impacts on the agricultural, forest and water resources of Kazakhstan. Climate change scenarios for Kazakhstan to assess both long-term (2×

Olga V. Pilifosova; Irina B. Eserkepova; Svetlana A. Dolgih

1997-01-01

162

Climate change, irrigation, and Israeli agriculture : will warming be harmful ?  

Microsoft Academic Search

The authors use a Ricardian model to test the relationship between annual net revenues and climate across Israeli farms. They find that it is important to include the amount of irrigation water available to each farm in order to measure the response of farms to climate. With irrigation water omitted, the model predicts that climate change is strictly beneficial. But

Aliza Fleischer; Ivgenia Lichtman; Robert Mendelsohn

2007-01-01

163

Adaptability and adaptations of California’s water supply system to dry climate warming  

Microsoft Academic Search

Economically optimal operational changes and adaptations for California’s water supply system are examined for a dry form\\u000a of climate warming (GFDL CM2.1 A2) with year 2050 water demands and land use. Economically adaptive water management for this\\u000a climate scenario is compared to a similar scenario with the historical climate. The effects of population growth and land\\u000a use alone are developed

Josué Medellín-Azuara; Julien J. Harou; Marcelo A. Olivares; Kaveh Madani; Jay R. Lund; Richard E. Howitt; Stacy K. Tanaka; Marion W. Jenkins; Tingju Zhu

2008-01-01

164

Doubled volatile organic compound emissions from subarctic tundra under simulated climate warming.  

PubMed

*Biogenic volatile organic compound (BVOC) emissions from arctic ecosystems are important in view of their role in global atmospheric chemistry and unknown feedbacks to global warming. These cold ecosystems are hotspots of climate warming, which will be more severe here than averaged over the globe. We assess the effects of climatic warming on non-methane BVOC emissions from a subarctic heath. *We performed ecosystem-based chamber measurements and gas chromatography-mass spectrometry (GC-MS) analyses of the BVOCs collected on adsorbent over two growing seasons at a wet subarctic tundra heath hosting a long-term warming and mountain birch (Betula pubescens ssp. czerepanovii) litter addition experiment. *The relatively low emissions of monoterpenes and sesquiterpenes were doubled in response to an air temperature increment of only 1.9-2.5 degrees C, while litter addition had a minor influence. BVOC emissions were seasonal, and warming combined with litter addition triggered emissions of specific compounds. *The unexpectedly high rate of release of BVOCs measured in this conservative warming scenario is far above the estimates produced by the current models, which underlines the importance of a focus on BVOC emissions during climate change. The observed changes have implications for ecological interactions and feedback effects on climate change via impacts on aerosol formation and indirect greenhouse effects. PMID:20456056

Faubert, Patrick; Tiiva, Päivi; Rinnan, Asmund; Michelsen, Anders; Holopainen, Jarmo K; Rinnan, Riikka

2010-07-01

165

Energy-balance mechanisms underlying consistent large-scale temperature responses in warm and cold climates  

NASA Astrophysics Data System (ADS)

Climate simulations show consistent large-scale temperature responses including amplified land-ocean contrast, high-latitude/low-latitude contrast, and changes in seasonality in response to year-round forcing, in both warm and cold climates, and these responses are proportional and nearly linear across multiple climate states. We examine the possibility that a small set of common mechanisms controls these large-scale responses using a simple energy-balance model to decompose the temperature changes shown in multiple lgm and abrupt4 × CO 2 simulations from the CMIP5 archive. Changes in the individual components of the energy balance are broadly consistent across the models. Although several components are involved in the overall temperature responses, surface downward clear-sky longwave radiation is the most important component driving land-ocean contrast and high-latitude amplification in both warm and cold climates. Surface albedo also plays a significant role in promoting high-latitude amplification in both climates and in intensifying the land-ocean contrast in the warm climate case. The change in seasonality is a consequence of the changes in land-ocean and high-latitude/low-latitude contrasts rather than an independent temperature response. This is borne out by the fact that no single component stands out as being the major cause of the change in seasonality, and the relative importance of individual components is different in cold and warm climates.

Izumi, Kenji; Bartlein, Patrick J.; Harrison, Sandy P.

2014-06-01

166

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

NASA Astrophysics Data System (ADS)

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.

Kirschbaum, Miko U. F.

2014-03-01

167

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

NASA Astrophysics Data System (ADS)

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.

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

2009-05-01

168

Predicting CO2 and CH4 Emissions from the Active Layer in Response to Climate Warming  

NASA Astrophysics Data System (ADS)

Permafrost resides beneath 25% of the land in the northern hemisphere. Observations and models suggest that permafrost is warming and thawing, the active layer is thickening, and previously frozen old soil carbon is being converted and released as CH4 and CO2. GHG release amounts and rates are poorly constrained, as is the ratio between CH4 vs CO2. This ratio is important because CH4 is significantly more powerful as a greenhouse gas than is CO2. The arctic is projected to experience more precipitation, and perhaps more thermokarst lake formation, both of which could result in wetter conditions that favor CH4 production. At the same time, permafrost degradation could lead to thermal erosion and other landscape processes that enhance drainage and drier soil conditions that favor CO2 production. As the community continues to develop techniques to identify how the soil moisture status of the Arctic landscape will evolve, we are developing a model to assess how a range of soil moisture conditions, from very wet to very dry, will drive changes in GHG emissions as warming continues. Our numerical model (named ARCHY) is designed to simulate coupled surface and subsurface processes in freezing environments. It can operate in 1-D, 2-D or 3-D, is time-dependent, and includes vertical and lateral water and vapor and gas movement in heterogeneous soils and between soils and atmosphere, snow cover, heat transport, solar irradiation, precipitation, temperature, small scale topography, change of phase between water, ice and vapor, and three spatially distributed species of microbes including aerobes, anaerobes, and methanotrophs. A number of comparisons to data, including a set of soil temperatures and CO2 and CH4 emissions vs time at Toolik lake, as well as experiments on unsaturated flow in a domain with a freezing boundary, provide validation of the coupled thermal, hydrologic and microbiological processes in our model. We are using this calibrated model to contrast gas emissions from thawing permafrost over a range of soil moisture conditions, from a warmer but drier soil to a warmer and wetter soil column. The simulations spin up the soil column from present conditions to a warmer climate over several years. Significantly more CH4 evolution occurs in a wet, anoxic column compared to the present day climate, while a drier, oxic column shows more CO2 evolution but less CH4. Amounts and rates of emissions can be quantified and related to soil moisture contents and climate temperature increases.

Wilson, C. J.; Travis, B. J.; Ossola, I.

2011-12-01

169

Performance of RegCM2.5\\/NCAR-CSM Nested System for the Simulation of Climate Change in East Asia Caused by Global Warming  

Microsoft Academic Search

Regional climate in East Asia under 1CO2 and 2CO2 conditions, was simulated for continuous 10-year periods by the RegCM2.5 developed by NCAR, using the output of a CO2 transient run from NCAR-CSM as lateral and surface boundary conditions in order to evaluate the performance of the nested system for the use of climate change simulation caused by global warming for

Hisashi Kato; Keiichi Nishizawa; Hiromaru Hirakuchi; Shinji Kadokura; Naoko Oshima; Filippo Giorgi

2001-01-01

170

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

171

The upper end of climate model temperature projections is inconsistent with past warming  

NASA Astrophysics Data System (ADS)

Climate models predict a large range of possible future temperatures for a particular scenario of future emissions of greenhouse gases and other anthropogenic forcings of climate. Given that further warming in coming decades could threaten increasing risks of climatic disruption, it is important to determine whether model projections are consistent with temperature changes already observed. This can be achieved by quantifying the extent to which increases in well mixed greenhouse gases and changes in other anthropogenic and natural forcings have already altered temperature patterns around the globe. Here, for the first time, we combine multiple climate models into a single synthesized estimate of future warming rates consistent with past temperature changes. We show that the observed evolution of near-surface temperatures appears to indicate lower ranges (5-95%) for warming (0.35-0.82 K and 0.45-0.93 K by the 2020s (2020-9) relative to 1986-2005 under the RCP4.5 and 8.5 scenarios respectively) than the equivalent ranges projected by the CMIP5 climate models (0.48-1.00 K and 0.51-1.16 K respectively). Our results indicate that for each RCP the upper end of the range of CMIP5 climate model projections is inconsistent with past warming.

Stott, Peter; Good, Peter; Jones, Gareth; Gillett, Nathan; Hawkins, Ed

2013-03-01

172

Effects of “realistic” land-cover change on a greenhouse-warmed African climate  

Microsoft Academic Search

The primary goal of this investigation is to focus on a “realistic” scenario for simulating impacts on regional African climate of future deforestation in a greenhouse-warmed world. Combined effects of plausible land-cover change and greenhouse warming are assessed by ‘time-slice’ simulations with an atmospheric general circulation model (AGCM) for the middle of the twenty first century. Three “time-slice” integrations have

K. Maynard; J.-F. Royer

2004-01-01

173

Researchers Find Genetic Response to Global Warming: Changing Climate Prompts Genetic Change in Squirrels  

NSDL National Science Digital Library

University of Alberta biologist Stan Boutin and his research team have recently published findings that North American red squirrels exhibit genetic changes in response to a warming climate. This Web site contains a University of Alberta press release detailing this first-ever demonstration of genetic adaptation to global warming. With implications that extend far beyond the immediate research concerns of geneticists and environmental scientists, Boutin's work as presented in this Web site should be interesting to wide audience.

Dey, Phoebe.

2003-01-01

174

Climatic changes and associated impacts in the Mediterranean resulting from a 2 °C global warming  

NASA Astrophysics Data System (ADS)

Climatic changes over the Mediterranean basin in 2031-2060, when a 2 °C global warming is most likely to occur, are investigated with the HadCM3 global circulation model and their impacts on human activities and natural ecosystem are assessed. Precipitation and surface temperature changes are examined through mean and extreme values analysis, under the A2 and B2 emission scenarios. Confidence in results is obtained via bootstrapping. Over the land areas, the warming is larger than the global average. The rate of warming is found to be around 2 °C in spring and winter, while it reaches 4 °C in summer. An additional month of summer days is expected, along with 2-4 weeks of tropical nights. Increase in heatwave days and decrease in frost nights are expected to be a month inland. In the northern part of the basin the widespread drop in summer rainfall is partially compensated by a winter precipitation increase. One to 3 weeks of additional dry days lead to a dry season lengthened by a week and shifted toward spring in the south of France and inland Algeria, and autumn elsewhere. In central Mediterranean droughts are extended by a month, starting a week earlier and ending 3 weeks later. The impacts of these climatic changes on human activities such as agriculture, energy, tourism and natural ecosystems (forest fires) are also assessed. Regarding agriculture, crops whose growing cycle occurs mostly in autumn and winter show no changes or even an increase in yield. In contrast, summer crops show a remarkable decrease of yield. This different pattern is attributed to a lengthier drought period during summer and to an increased rainfall in winter and autumn. Regarding forest fire risk, an additional month of risk is expected over a great part of the basin. Energy demand levels are expected to fall significantly during a warmer winter period inland, whereas they seem to substantially increase nearly everywhere during summer. Extremely high summer temperatures in the Mediterranean, coupled with improved climate conditions in northern Europe, may lead to a gradual decrease in summer tourism in the Mediterranean, but an increase in spring and autumn.

Giannakopoulos, C.; Le Sager, P.; Bindi, M.; Moriondo, M.; Kostopoulou, E.; Goodess, C. M.

2009-08-01

175

Nutritional requirements of sheep, goats and cattle in warm climates: a meta-analysis.  

PubMed

The objective of the study was to update energy and protein requirements of growing sheep, goats and cattle in warm areas through a meta-analysis study of 590 publications. Requirements were expressed on metabolic live weight (MLW=LW0.75) and LW1 basis. The maintenance requirements for energy were 542.64 and 631.26 kJ ME/kg LW0.75 for small ruminants and cattle, respectively, and the difference was significant (P<0.01). The corresponding requirement for 1 g gain was 24.3 kJ ME without any significant effect of species. Relative to LW0.75, there was no difference among genotypes intra-species in terms of ME requirement for maintenance and gain. However, small ruminants of warm and tropical climate appeared to have higher ME requirements for maintenance relative to live weight (LW) compared with temperate climate ones and cattle. Maintenance requirements for protein were estimated via two approaches. For these two methods, the data in which retained nitrogen (RN) was used cover the same range of variability of observations. The regression of digestible CP intake (DCPI, g/kg LW0.75) against RN (g/kg LW0.75) indicated that DCP requirements are significantly higher in sheep (3.36 g/kg LW0.75) than in goats (2.38 g/kg LW0.75), with cattle intermediate (2.81 g/kg LW0.75), without any significant difference in the quantity of DCPI/g retained CP (RCP) (40.43). Regressing metabolisable protein (MP) or minimal digestible protein in the intestine (PDImin) against RCP showed that there was no difference between species and genotypes, neither for the intercept (maintenance=3.51 g/kg LW0.75 for sheep and goat v. 4.35 for cattle) nor for the slope (growth=0.60 g MP/g RCP). The regression of DCP against ADG showed that DCP requirements did not differ among species or genotypes. These new feeding standards are derived from a wider range of nutritional conditions compared with existing feeding standards as they are based on a larger database. The standards seem to be more appropriate for ruminants in warm and tropical climates around the world. PMID:24902005

Salah, N; Sauvant, D; Archimède, H

2014-09-01

176

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

PubMed Central

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

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

2013-01-01

177

Teaching about Climate Change: Cool Schools Tackle Global Warming.  

ERIC Educational Resources Information Center

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…

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

178

Travelling through a warming world: climate change and migratory species  

Microsoft Academic Search

Long-distance migrations are among the wonders of the natural world, but this multi- taxon review shows that the characteristics of species that undertake such movements appear to make them particularly vulnerable to detrimental impacts of climate change. Migrants are key com- ponents of biological systems in high latitude regions, where the speed and magnitude of climate change impacts are greatest.

Robert A. Robinson; Humphrey Q. P. Crick; Jennifer A. Learmonth; Ilya M. D. Maclean; Chris D. Thomas; Franz Bairlein; Mads C. Forchhammer; Charles M. Francis; Jennifer A. Gill; Brendan J. Godley; John Harwood; Graeme C. Hays; Brian Huntley; Anthony M. Hutson; Graham J. Pierce; Mark M. Rehfisch; David W. Sims; M. Begoña Santos; Timothy H. Sparks; David A. Stroud; Marcel E. Visser

2008-01-01

179

The Early Climate History of Mars: "Warm and Wet" or "Cold and Icy"?  

NASA Astrophysics Data System (ADS)

The Amazonian climate (last ~66% of history) was much like today, a cold and dry climate regime, characterized by the latitudinal migration of surface ice in response to variations in spin-axis/orbital parameters. But what characterized the Noachian climate (first ~20% of history)? Some data support a "warm and wet" early Mars, but this evidence has been challenged. New models of early Mars climate (Forget, Wordsworth et al.) find that for atmospheric pressures greater than a few hundred millibars, surface temperatures vary with altitude due to atmosphere-surface thermal coupling: an adiabatic cooling effect (ACE) results in deposition of snow and ice at high altitudes, in contrast to Amazonian conditions. Without other warming mechanisms, no combination of parameters lead to mean annual surface temperatures (MAT) consistent with widespread liquid water anywhere on the planet. The ACE causes southern highland region temperatures to fall significantly below the global average leading to a "Noachian Icy Highlands" scenario: Water is transported to the highlands from low-lying regions due to the ACE and snows out to form an extended H2O ice cap at the southern pole, and altitude-dependent snow and ice deposits down to lower southern latitudes. Could the predictions of this "Noachian Icy Highlands" model be consistent with the many lines of evidence traditionally cited for a "warm, wet" early Mars? Perturbing this predominant Noachian environment with punctuated impacts and volcanism/greenhouse gases would lead to raising of global surface temperatures toward the melting point of water, with the following consequences: 1) ice above the surface ice stability line undergoes rapid altitude/latitude dependent warming during each Mars summer; 2) meltwater runoff from the continuous ice sheet drains and flows downslope to the edge of the ice sheet, where meltwater channels encounter cratered terrain, forming closed-basin and open-basin lakes; 3) seasonal top-down heating and melting of the top tens of meters of continuous ice produce a volume of water well in excess of the total volume interpreted to have occupied open-basin/closed basin lakes; 4) this meltwater initially erodes into the dry regolith down to the top of the ice table, producing a perched aquifer and more efficient erosion than infiltration alone; 5) at the end of the annual melting period, temperatures return to below 0°C, meltwater freezes and sublimes, returning to high altitudes as snowfall to replenish the snow and ice deposit; 6) this Noachian icy highlands, ACE-dominated water cycle persists until MAT drops to <0°C. The icy Noachian highlands/punctuated volcanism scenario appears to be able to account for the: 1) source and volume of water required for valley networks; 2) presence of closed/open-basin lakes; 4) evidence for recurring phases of activity over millions of years; 5) small amounts of net erosion; 6) relatively poor stream integration and lower order; 7) presence of a surface hydrological cycle that can replenish the source area and cause recurring activity with a small total budget of water; and 8) presence of melting and runoff in a Late Noachian climate compatible with other constraints (e.g., faint young Sun, low atmospheric pressure).

Head, James

2013-04-01

180

Climatic warming increases winter wheat yield but reduces grain nitrogen concentration in east China.  

PubMed

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

Tian, Yunlu; Zheng, Chengyan; Chen, Jin; Chen, Changqing; Deng, Aixing; Song, Zhenwei; Zhang, Baoming; Zhang, Weijian

2014-01-01

181

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

PubMed Central

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

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

2014-01-01

182

Climate warming mediates negative impacts of rapid pond drying for three amphibian species.  

PubMed

Anthropogenic climate change will present both opportunities and challenges for pool-breeding amphibians. Increased water temperature and accelerated drying may directly affect larval growth, development, and survival, yet the combined effects of these processes on larvae with future climate change remain poorly understood. Increased surface temperatures are projected to warm water and decrease water inputs, leading to earlier and faster wetland drying. So it is often assumed that larvae will experience negative synergistic impacts with combined warming and drying. However, an alternative hypothesis is that warming-induced increases in metabolic rate and aquatic resource availability might compensate for faster drying rates, generating antagonistic larval responses. We conducted a mesocosm experiment to test the individual and interactive effects of pool permanency (permanent vs. temporary) and water temperature (ambient vs. (+) -3 degrees C) on three anurans with fast-to-slow larval development rates (Great Basin spadefoot [Spea intermontana], Pacific chorus frog [Pseudacris regilla], and northern red-legged frog [Rana aurora]). We found that although tadpoles in warmed pools reached metamorphosis 15-17 days earlier, they did so with little cost (< 2 mm) to size, likely due to greater periphyton growth in warmed pools easing drying-induced resource competition. Warming and drying combined to act antagonistically on early growth (P = 0.06) and survival (P = 0.06), meaning the combined impact was less than the sum of the individual impacts. Warming and drying acted additively on time to and size at metamorphosis. These nonsynergistic impacts may result from cotolerance of larvae to warming and drying, as well as warming helping to offset negative impacts of drying. Our results indicate that combined pool warming and drying may not always be harmful for larval amphibians. However, they also demonstrate that antagonistic responses are difficult to predict, which poses a challenge to proactive conservation and management. Our study highlights the importance of considering the nature of multiple stressor interactions as amphibians are exposed to an increasing number of anthropogenic threats. PMID:24933805

O'Regan, Sacha M; Palen, Wendy J; Anderson, Sean C

2014-04-01

183

Effects of Global Warming on Predatory Bugs Supported by Data Across Geographic and Seasonal Climatic Gradients  

PubMed Central

Global warming may affect species abundance and distribution, as well as temperature-dependent morphometric traits. In this study, we first used historical data to document changes in Orius (Heteroptera: Anthocoridae) species assemblage and individual morphometric traits over the past seven decades in Israel. We then tested whether these changes could have been temperature driven by searching for similar patterns across seasonal and geographic climatic gradients in a present survey. The historical records indicated a shift in the relative abundance of dominant Orius species; the relative abundance of O. albidipennis, a desert-adapted species, increased while that of O. laevigatus decreased in recent decades by 6 and 10–15 folds, respectively. These shifts coincided with an overall increase of up to 2.1°C in mean daily temperatures over the last 25 years in Israel. Similar trends were found in contemporary data across two other climatic gradients, seasonal and geographic; O. albidipennis dominated Orius assemblages under warm conditions. Finally, specimens collected in the present survey were significantly smaller than those from the 1980’s, corresponding to significantly smaller individuals collected now during warmer than colder seasons. Taken together, results provide strong support to the hypothesis that temperature is the most likely driver of the observed shifts in species composition and body sizes because (1) historical changes in both species assemblage and body size were associated with rising temperatures in the study region over the last few decades; and (2) similar changes were observed as a result of contemporary drivers that are associated with temperature. PMID:23805249

Schuldiner-Harpaz, Tarryn; Coll, Moshe

2013-01-01

184

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

PubMed

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

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

185

Pacific Shallow Meridional Overturning Circulation in a Warming Climate  

E-print Network

By analyzing a set of the Coupled Model Intercomparison Project phase 3 (CMIP3) climate model projections of the twenty-first century, it is found that the shallow meridional overturning of the Pacific subtropical cells ...

Wang, Daiwei

186

Marshy pools on permafrost mitigate landscape-scale climate warming  

NASA Astrophysics Data System (ADS)

Starting 5000 years ago, small marshy lakes dotting northern Siberia became significant carbon sinks, cooling the climate on a landscape scale. Researchers from the University of Alaska Fairbanks (UAF) published their findings in Nature online on 16 July.

Wendel, JoAnna

2014-07-01

187

Dividing climate change: global warming in the Indian mass media  

Microsoft Academic Search

Much research has now been conducted into the representation of climate change in the media. Specifically, the communication\\u000a of climate change from scientists and policy-makers to the public via the mass media has been a subject of major interest\\u000a because of its implications for creating national variation in public understanding of a global environmental issue. However,\\u000a to date, no study

Simon Billett

2010-01-01

188

Using physiology to predict the responses of ants to climatic warming.  

PubMed

Physiological intolerance of high temperatures places limits on organismal responses to the temperature increases associated with global climatic change. Because ants are geographically widespread, ecologically diverse, and thermophilic, they are an ideal system for exploring the extent to which physiological tolerance can predict responses to environmental change. Here, we expand on simple models that use thermal tolerance to predict the responses of ants to climatic warming. We investigated the degree to which changes in the abundance of ants under warming reflect reductions in the thermal niche space for their foraging. In an eastern deciduous forest system in the United States with approximately 40 ant species, we found that for some species, the loss of thermal niche space for foraging was related to decreases in abundance with increasing experimental climatic warming. However, many ant species exhibited no loss of thermal niche space. For one well-studied species, Temnothorax curvispinosus, we examined both survival of workers and growth of colonies (a correlate of reproductive output) as functions of temperature in the laboratory, and found that the range of thermal tolerances for colony growth was much narrower than for survival of workers. We evaluated these functions in the context of experimental climatic warming and found that the difference in the responses of these two attributes to temperature generates differences in the means and especially the variances of expected fitness under warming. The expected mean growth of colonies was optimized at intermediate levels of warming (2-4°C above ambient); yet, the expected variance monotonically increased with warming. In contrast, the expected mean and variance of the survival of workers decreased when warming exceeded 4°C above ambient. Together, these results for T. curvispinosus emphasize the importance of measuring reproduction (colony growth) in the context of climatic change: indeed, our examination of the loss of thermal niche space with the larger species pool could be missing much of the warming impact due to these analyses being based on survival rather than reproduction. We suggest that while physiological tolerance of temperature can be a useful predictive tool for modeling responses to climatic change, future efforts should be devoted to understanding the causes and consequences of variability in models of tolerance calibrated with different metrics of performance and fitness. PMID:23892370

Diamond, Sarah E; Penick, Clint A; Pelini, Shannon L; Ellison, Aaron M; Gotelli, Nicholas J; Sanders, Nathan J; Dunn, Robert R

2013-12-01

189

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

E-print Network

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

Baez, John

190

Vulnerability of Lake Tahoe (CA-NV) mixing patterns in response to global warming and climate change  

Microsoft Academic Search

Meteorological-driven processes exert large and diverse impacts on lakes internal heating, cooling and mixing. Thus, lakes' mixing pattern and ecosystem will likely be affected with continued global warming and climate change. The impact of climate change on Lake Tahoe (California-Nevada) was investigated here as a case study of climate change effects on the physical processes occurring within the lake. Climate

G. B. Sahoo; G. Schladow; J. E. Reuter

2008-01-01

191

Climate warming affects biological invasions by shifting interactions of plants and herbivores.  

PubMed

Plants and herbivorous insects can each be dramatically affected by temperature. Climate warming may impact plant invasion success directly but also indirectly through changes in their natural enemies. To date, however, there are no tests of how climate warming shifts the interactions among invasive plants and their natural enemies to affect invasion success. Field surveys covering the full latitudinal range of invasive Alternanthera philoxeroides in China showed that a beetle introduced for biocontrol was rare or absent at higher latitudes. In contrast, plant cover and mass increased with latitude. In a 2-year field experiment near the northern limit of beetle distribution, we found the beetle sustained populations across years under elevated temperature, dramatically decreasing A. philoxeroides growth, but it failed to overwinter in ambient temperature. Together, these results suggest that warming will allow the natural enemy to expand its range, potentially benefiting biocontrol in regions that are currently too cold for the natural enemy. However, the invader may also expand its range further north in response to warming. In such cases where plants tolerate cold better than their natural enemies, the geographical gap between plant and herbivorous insect ranges may not disappear but will shift to higher latitudes, leading to a new zone of enemy release. Therefore, warming will not only affect plant invasions directly but also drive either enemy release or increase that will result in contrasting effects on invasive plants. The findings are also critical for future management of invasive species under climate change. PMID:23640751

Lu, Xinmin; Siemann, Evan; Shao, Xu; Wei, Hui; Ding, Jianqing

2013-08-01

192

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

PubMed Central

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

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

2014-01-01

193

Effect of wearing an ice cooling jacket on repeat sprint performance in warm/humid conditions  

PubMed Central

Objective: To examine the effect of cooling the skin with an ice jacket before and between exercise bouts (to simulate quarter and half time breaks) on prolonged repeat sprint exercise performance in warm/humid conditions. Methods: After an initial familiarisation session, seven trained male hockey players performed two testing sessions (seven days apart), comprising an 80 minute intermittent, repeat sprint cycling exercise protocol inside a climate chamber set at 30°C and 60% relative humidity. On one occasion a skin cooling procedure was implemented (in random counterbalanced order), with subjects wearing an ice cooling jacket both before (for five minutes) and in the recovery periods (2 x 5 min and 1 x 10 min) during the test. Measures of performance (work done and power output on each sprint), heart rates, blood lactate concentrations, core (rectal) and skin temperatures, sweat loss, perceived exertion, and ratings of thirst, thermal discomfort, and fatigue were obtained in both trials. Results: In the cooling condition, chest (torso) skin temperature, thermal discomfort, and rating of thirst were all significantly lower (p<0.05), but no significant difference (p>0.05) was observed between conditions for measures of work done, power output, heart rate, blood lactate concentration, core or mean skin temperature, perceived exertion, sweat loss, or ratings of fatigue. However, high effect sizes indicated trends to lowered lactate concentrations, sweat loss, and mean skin temperatures in the cooling condition. Conclusions: The intermittent use of an ice cooling jacket, both before and during a repeat sprint cycling protocol in warm/humid conditions, did not improve physical performance, although the perception of thermal load was reduced. Longer periods of cooling both before and during exercise (to lower mean skin temperature by a greater degree than observed here) may be necessary to produce such a change. PMID:12663361

Duffield, R; Dawson, B; Bishop, D; Fitzsimons, M; Lawrence, S

2003-01-01

194

Climate Response to Anomalously Large and Small Atlantic Warm Pools during the Summer  

E-print Network

of the Rocky Mountains and thus decreases (increases) the summer rainfall over the central United States AWP's influ- ences on Western Hemisphere summer rainfall and Atlantic hurricane activity (summer hereClimate Response to Anomalously Large and Small Atlantic Warm Pools during the Summer CHUNZAI WANG

Wang, Chunzai

195

Climate Warming, Marine Protected Areas and the Ocean-Scale Integrity of Coral Reef Ecosystems  

E-print Network

Climate Warming, Marine Protected Areas and the Ocean-Scale Integrity of Coral Reef Ecosystems States of America, 4 ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville of Warwick, Department of Biological Sciences, Coventry, United Kingdom Abstract Coral reefs have emerged

Paris-Sud XI, Université de

196

Characteristics of Permafrost Forests in Siberia and Potential Responses to Warming Climate  

Microsoft Academic Search

\\u000a The purpose of this chapter is to synthesize what have been reported in the preceding chapters, and to discuss (1) major characteristics\\u000a in the structure, function, and development patterns of the larch forests that grow on permafrost, and (2) how their structure\\u000a and function may change due to the warming climate.

A. Osawa; Y. Matsuura; T. Kajimoto

197

Climate change, global warming and coral reefs: Modelling the effects of temperature  

Microsoft Academic Search

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

M. James C. Crabbe

2008-01-01

198

The Return of Dr Strangelove The politics of climate engineering as a response to global warming  

E-print Network

volcanic eruptions to counter the warming effects of carbon pollution. Engineering the planet's climate phytoplankton that absorb carbon dioxide as they grow and, on death, take carbon to the ocean depths. Trials nutrient-rich cold water from the deep to encourage algal blooms that suck carbon dioxide from the air

Green, Donna

199

The effects of climate change due to global warming on river flows in Great Britain  

Microsoft Academic Search

Global warming due to an increasing concentration of greenhouse gases in the atmosphere will affect temperature and rainfall, and hence river flows and water resources. This paper presents results from an investigation into potential changes in river flows in 21 catchments in Great Britain, using a daily rainfall-runoff model and both equilibrium and transient climate change scenarios. Annual runoff was

N. W. Arnell; N. S. Reynard

1996-01-01

200

Northward migration of permafrost along the Mackenzie highway and climatic warming  

Microsoft Academic Search

Based on two field surveys of permafrost distribution, conducted 26 years apart, along the Mackenzie Highway south of Great Slave Lake, Canada, the southern limit of the sporadic discontinuous permafrost zone in the region has migrated northward by about 120 km. To substantiate that the disappearance of perennial frozen ground is largely caused by climatic warming, a detailed trend analysis

Y. T. John Kwong; T. Y. Gan

1994-01-01

201

Climate warming is lowering levels of dissolved carbon in the Yukon River  

NSDL National Science Digital Library

Dissolved organic carbon (DOC) export, normalized to water discharge, during the growing season from 1978 to 1980 was compared with that taken from 2001 to 2003. It was found that climate warming on frozen soils increases the flow path, residence time, and microbial mineralization of DOC in the soil's active layer and groundwater, ultimately decreasing DOC export.

Al., Striegl E.; Agu

202

Pimping climate change: Richard Branson, global warming, and the performance of green capitalism  

Microsoft Academic Search

On 21 September 2006 UK über-entrepreneur and Virgin Group Chairman Richard Branson pledged approximately £1.6 billion, the equivalent of all the profits from Virgin Atlantic and Virgin Trains for the next ten years, to fighting climate change. Since then, Branson has restated his commitment to action on global warming, including investment in technologies for sequestering carbon dioxide from the atmosphere.

Scott Prudham

2009-01-01

203

Floods, Droughts and Global Warming: Rolling the Climate Dice  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

204

Is the climate warming or cooling? David R. Easterling1  

E-print Network

are found in the last 34 years of the observed record, and in climate model simulations of the 20th and 21st global temperatures remain well above the long-term average. The unusually strong 1997­1998 El Nin~o

205

Adapting California's water system to warm vs. dry climates  

E-print Network

heavily on water storage in snowpack, reservoirs, and aquifers to meet demands through the dry growing in the snowpack if melted) (Hamlet et al. 2005) and has affected deliveries and reservoir storage levels adaptations. A warmer climate alone reduces water deliveries and increases costs, but much less than a warmer

Pasternack, Gregory B.

206

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

PubMed

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

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

2014-07-01

207

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

PubMed

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

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

2014-07-01

208

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

PubMed

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

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

2010-11-01

209

Climate warming and the decline of amphibians and reptiles in Europe  

Microsoft Academic Search

ABSTRACT Aim,We,explore,the relationship between,current,European,distributions,of amphibian and reptile species and observed climate, and project species potential distributions into the future. Potential impacts of climate warming,are assessed by quantifying,the magnitude,and,direction of modelled,distributional shifts for every species. In particular we ask, first, what proportion of amphibian and reptile species are projected,to lose and,gain suitable climate,space in the future? Secondly, do species projections vary

M. B. Araújo; W. Thuiller; R. G. Pearson

2006-01-01

210

Flowering phenology change and climate warming in southwestern Ohio  

Microsoft Academic Search

Global surface temperature has increased markedly over the last 100 years. This increase has a variety of implications for\\u000a human societies, and for ecological systems. One of the most obvious ways ecosystems are affected by global climate change\\u000a is through alteration of organisms’ developmental timing (phenology). We used annual botanical surveys that documented the\\u000a first flowering for an array of species

Ryan W. McEwanRobert; Robert J. Brecha; Donald R. GeigerGrace; Grace P. John

2011-01-01

211

Regional climate change under high-end global warming  

Microsoft Academic Search

Global emissions of greenhouse gases have continued to rise throughout the 20th and 21st centuries. If no steps are taken to reduce these emissions, it is likely that global temperatures will exceed the limit of 2 deg.C by 2100 (relative to the preindustrial period) desired by the EU. The climate projections from the IPCC Fourth Assessment Report (AR4) suggest that

Michael Sanderson; Deborah Hemming; Richard Betts

2010-01-01

212

Increases in flood magnitudes in California under warming climates  

USGS Publications Warehouse

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.

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

2013-01-01

213

Shifting suitability for malaria vectors across Africa with warming climates  

E-print Network

.03% Anopheles arabiensis Present 14,528,957 520,289,130 14,528,957 520,289,130 B2 +2.03% +2.77% -26.44% -32.95% A2 +1.96% +2.70% -39.46% -26.07% Summary of overall tendencies in human exposure to two species of malaria vectors across Africa under two scenarios...' niche models and relative risk maps. PLoS ONE 2007, 2:e824. 18. Lieshout Mv, Kovats RS, Livermore MTJ, Martens P: Climate Page 5 of 6 (page number not for citation purposes) reduction nonetheless includes increasing malaria vector presence in areas...

Peterson, A. Townsend

2009-05-10

214

Climate change in cities due to global warming and urban effects  

NASA Astrophysics Data System (ADS)

Urbanisation is estimated to result in 6 billion urban dwellers by 2050. Cities will be exposed to climate change from greenhouse gas induced radiative forcing, and localised effects from urbanisation such as the urban heat island. An urban land-surface model has been included in the HadAM3 Global Climate Model. It shows that regions of high population growth coincide with regions of high urban heat island potential, most notably in the Middle East, the Indian sub-continent, and East Africa. Climate change has the capacity to modify the climatic potential for urban heat islands, with increases of 30% in some locations, but a global average reduction of 6%. Warming and extreme heat events due to urbanisation and increased energy consumption are simulated to be as large as the impact of doubled CO2 in some regions, and climate change increases the disparity in extreme hot nights between rural and urban areas.

McCarthy, Mark P.; Best, Martin J.; Betts, Richard A.

2010-05-01

215

Abrupt climate change in West Antarctica and Greenland during the last deglacial warming  

NASA Astrophysics Data System (ADS)

The WAIS Divide ice core is the first Southern Hemisphere record with precision similar to ice cores from Greenland. The annually resolved timescale and small gas-age ice-age difference allow the phasing of climate change in the two hemispheres to be compared with unprecedented precision. We focus on the three abrupt climate changes in Greenland during the deglacial transition and the corresponding changes at WAIS Divide. The onset of the Antarctic Cold Reversal (ACR) is clearly defined in the WAIS Divide record and lagged the Bolling-Allerod (BA) warming by 150×50 years. The phasing of the other two abrupt climate changes cannot be distinguished from synchronous with an uncertainty of ~200 years because the transitions from warming to cooling (or cooling to warming) are not distinct in the WAIS Divide record. The lead-lag relationships of no more than a couple centuries confirm the tight coupling between hemispheres during the deglaciation. The independent timescale of WAIS Divide confirms that meltwater Pulse 1a began near-coincident with the BA and ACR although the lack of direct synchronization between the annually dated ice-core imescales and the radiometrically dated coral timescale prevents the phasing from being known to better than a couple of centuries. A new observation from WAIS Divide is that accumulation increased ~40% between 12.0 and 11.6 ka, with the accumulation increase ending approximately coincident with the warming at the end of the Younger Dryas in Greenland. Other Antarctic ice cores lack timescales with sufficient resolution to identify such abrupt changes so it is unclear how much of Antarctica was affected by the increased accumulation rates. The inter-hemispheric relationships are often limited to a discussion of warming, but the WAIS Divide records suggests that the moisture transport may be another important constraint on the mechanisms that drive abrupt climate change.

Fudge, T. J.; Steig, E. J.; Brook, E.; Buizert, C.; Conway, H.; Ding, Q.; Markle, B. R.; McConnell, J. R.; Pedro, J. B.; Schoenemann, S. W.; Severinghaus, J. P.; Sigl, M.; Sowers, T. A.; Taylor, K.; Waddington, E. D.

2013-12-01

216

Is This Global Warming? Communicating the Intangibles of Climate Change  

NASA Astrophysics Data System (ADS)

Unlike weather, which is immediate, tangible, and relevant on a daily basis, climate change is long-term, slow to evolve, and often difficult to relate to the public's daily concerns. By explaining global-change research to wide and diverse audiences through a variety of vehicles, including publications, exhibits, Web sites, and television B-roll, UCAR has gained experience and perspective on the challenges involved. This talk will explore some of the lessons learned and some of the key difficulties that face global-change communicators, including: --The lack of definitive findings on regional effects of global change -- The long time frame in which global change plays out, versus the short attention span of media, the public, and policy makers --The use of weather events as news pegs (they pique interest, but they may not be good exemplars of global change and are difficult to relate directly to changes in greenhouse-gas emissions) --The perils of the traditional journalistic technique of point-counterpoint in discussing climate change --The presence of strong personal/political convictions among various interest groups and how these affect the message(s) conveyed

Warner, L.; Henson, R.

2004-05-01

217

THE KINEMATICS AND PHYSICAL CONDITIONS OF WARM IONIZED GAS IN SPIRAL DISKS  

E-print Network

THE KINEMATICS AND PHYSICAL CONDITIONS OF WARM IONIZED GAS IN SPIRAL DISKS Matthew A. Bershady1 integral-field echelle observations of the warm, ionized phase of the interstellar medium (ISM) of many Way and high-z galaxies. 1. Introduction What drives gas velocity dispersions in star-forming galaxies

Bershady, Matthew A.

218

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

NASA Astrophysics Data System (ADS)

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.

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

219

Long-term effects of warming and ocean acidification are modified by seasonal variation in species responses and environmental conditions  

PubMed Central

Warming of sea surface temperatures and alteration of ocean chemistry associated with anthropogenic increases in atmospheric carbon dioxide will have profound consequences for a broad range of species, but the potential for seasonal variation to modify species and ecosystem responses to these stressors has received little attention. Here, using the longest experiment to date (542 days), we investigate how the interactive effects of warming and ocean acidification affect the growth, behaviour and associated levels of ecosystem functioning (nutrient release) for a functionally important non-calcifying intertidal polychaete (Alitta virens) under seasonally changing conditions. We find that the effects of warming, ocean acidification and their interactions are not detectable in the short term, but manifest over time through changes in growth, bioturbation and bioirrigation behaviour that, in turn, affect nutrient generation. These changes are intimately linked to species responses to seasonal variations in environmental conditions (temperature and photoperiod) that, depending upon timing, can either exacerbate or buffer the long-term directional effects of climatic forcing. Taken together, our observations caution against over emphasizing the conclusions from short-term experiments and highlight the necessity to consider the temporal expression of complex system dynamics established over appropriate timescales when forecasting the likely ecological consequences of climatic forcing. PMID:23980249

Godbold, Jasmin A.; Solan, Martin

2013-01-01

220

Potential malaria outbreak in Germany due to climate warming: risk modelling based on temperature measurements and regional climate models  

Microsoft Academic Search

Purpose  Climate warming can change the geographic distribution and intensity of the transmission of vector-borne diseases such as\\u000a malaria. The transmitted parasites usually benefit from increased temperatures as both their reproduction and development\\u000a are accelerated. Lower Saxony (northwestern Germany) has been a malaria region until the 1950s, and the vector species are\\u000a still present throughout Germany. This gave reason to investigate

Marcel Holy; Gunther Schmidt; Winfried Schröder

2011-01-01

221

A regional response in mean westerly circulation and rainfall to projected climate warming over Tasmania, Australia  

NASA Astrophysics Data System (ADS)

Coupled ocean-atmosphere general circulation models (GCMs) lack sufficient resolution to model the regional detail of changes to mean circulation and rainfall with projected climate warming. In this paper, changes in mean circulation and rainfall in GCMs are compared to those in a variable resolution regional climate model, the Conformal Cubic Atmospheric Model (CCAM), under a high greenhouse gas emissions scenario. The study site is Tasmania, Australia, which is positioned within the mid-latitude westerlies of the southern hemisphere. CCAM projects a different response in mean sea level pressure and mid-latitude westerly circulation to climate warming to the GCMs used as input, and shows greater regional detail of the boundaries between regions of increasing and decreasing rainfall. Changes in mean circulation dominate the mean rainfall response in western Tasmania, whereas changes to rainfall in the East Coast are less related to mean circulation changes. CCAM projects an amplification of the dominant westerly circulation over Tasmania and this amplifies the seasonal cycle of wet winters and dry summers in the west. There is a larger change in the strength than in the incidence of westerly circulation and rainfall events. We propose the regional climate model displays a more sensitive atmospheric response to the different rates of warming of land and sea than the GCMs as input. The regional variation in these results highlight the need for dynamical downscaling of coupled general circulation models to finely resolve the influence of mean circulation and boundaries between regions of projected increases and decreases in rainfall.

Grose, Michael R.; Corney, Stuart P.; Katzfey, Jack J.; Bennett, James C.; Holz, Gregory K.; White, Christopher J.; Bindoff, Nathaniel L.

2013-04-01

222

Ocean cleaning stations under a changing climate: biological responses of tropical and temperate fish-cleaner shrimp to global warming.  

PubMed

Cleaning symbioses play an important role in the health of certain coastal marine communities. These interspecific associations often occur at specific sites (cleaning stations) where a cleaner organism (commonly a fish or shrimp) removes ectoparasites/damaged tissue from a 'client' (a larger cooperating fish). At present, the potential impact of climate change on the fitness of cleaner organisms remains unknown. This study investigated the physiological and biochemical responses of tropical (Lysmata amboinensis) and temperate (L. seticaudata) cleaner shrimp to global warming. Specifically, thermal limits (CTMax), metabolic rates, thermal sensitivity, heat shock response (HSR), lipid peroxidation [malondialdehyde (MDA) concentration], lactate levels, antioxidant (GST, SOD and catalase) and digestive enzyme activities (trypsin and alkaline phosphatase) at current and warming (+3 °C) temperature conditions. In contrast to the temperate species, CTMax values decreased significantly from current (24-27 °C) to warming temperature conditions (30 °C) for the tropical shrimp, where metabolic thermal sensitivity was affected and the HSR was significantly reduced. MDA levels in tropical shrimp increased dramatically, indicating extreme cellular lipid peroxidation, which was not observed in the temperate shrimp. Lactate levels, GST and SOD activities were significantly enhanced within the muscle tissue of the tropical species. Digestive enzyme activities in the hepatopancreas of both species were significantly decreased by warmer temperatures. Our data suggest that the tropical cleaner shrimp will be more vulnerable to global warming than the temperate Lysmata seticaudata; the latter evolved in a relatively unstable environment with seasonal thermal variations that may have conferred greater adaptive plasticity. Thus, tropical cleaning symbioses may be challenged at a greater degree by warming-related anthropogenic forcing, with potential cascading effects on the health and structuring of tropical coastal communities (e.g. coral reefs). PMID:24771544

Rosa, Rui; Lopes, Ana Rita; Pimentel, Marta; Faleiro, Filipa; Baptista, Miguel; Trübenbach, Katja; Narciso, Luis; Dionísio, Gisela; Pegado, Maria Rita; Repolho, Tiago; Calado, Ricardo; Diniz, Mário

2014-10-01

223

Expansion of global drylands under a warming climate  

NASA Astrophysics Data System (ADS)

Global drylands encompassing hyper-arid, arid, semiarid, and dry subhumid areas cover about 41% of the earth's terrestrial surface and are home to more than a third of the world's population. By analyzing observations for 1948-2008 and climate model simulations for 1948-2100, we show that global drylands have expanded in last sixty years and will continue to expand in the 21st century. By the end of this century, the world's drylands under a high greenhouse gas emission scenario are projected to be 5.8 × 106 km2 (or 10%) larger than in the 1961-1990 climatology. The major expansion of arid regions will occur over southwest North America, the northern fringe of Africa, southern Africa, and Australia, while major expansions of semiarid regions will occur over the north side of the Mediterranean, southern Africa, and North and South America. The global dryland expansions will increase the population affected by water scarcity and land degradations.

Feng, S.; Fu, Q.

2013-06-01

224

Climate warming could reduce runoff significantly in New England, USA  

USGS Publications Warehouse

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.

Huntington, T.G.

2003-01-01

225

Above- and belowground linkages in Sphagnum peatland: climate warming affects plant-microbial interactions.  

PubMed

Peatlands contain approximately one third of all soil organic carbon (SOC). Warming can alter above- and belowground linkages that regulate soil organic carbon dynamics and C-balance in peatlands. Here we examine the multiyear impact of in situ experimental warming on the microbial food web, vegetation, and their feedbacks with soil chemistry. We provide evidence of both positive and negative impacts of warming on specific microbial functional groups, leading to destabilization of the microbial food web. We observed a strong reduction (70%) in the biomass of top-predators (testate amoebae) in warmed plots. Such a loss caused a shortening of microbial food chains, which in turn stimulated microbial activity, leading to slight increases in levels of nutrients and labile C in water. We further show that warming altered the regulatory role of Sphagnum-polyphenols on microbial community structure with a potential inhibition of top predators. In addition, warming caused a decrease in Sphagnum cover and an increase in vascular plant cover. Using structural equation modelling, we show that changes in the microbial food web affected the relationships between plants, soil water chemistry, and microbial communities. These results suggest that warming will destabilize C and nutrient recycling of peatlands via changes in above- and belowground linkages, and therefore, the microbial food web associated with mosses will feedback positively to global warming by destabilizing the carbon cycle. This study confirms that microbial food webs thus constitute a key element in the functioning of peatland ecosystems. Their study can help understand how mosses, as ecosystem engineers, tightly regulate biogeochemical cycling and climate feedback in peatlands. PMID:23504838

Jassey, Vincent E J; Chiapusio, Geneviève; Binet, Philippe; Buttler, Alexandre; Laggoun-Défarge, Fatima; Delarue, Frédéric; Bernard, Nadine; Mitchell, Edward A D; Toussaint, Marie-Laure; Francez, André-Jean; Gilbert, Daniel

2013-03-01

226

Potential impacts of climate warming on water supply reliability in the Tuolumne and Merced River Basins, California.  

PubMed

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

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

2014-01-01

227

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

PubMed Central

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

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

2014-01-01

228

Global warming is breeding social conflict: The subtle impact of climate change threat on authoritarian tendencies  

Microsoft Academic Search

Climate change can increase societies’ propensity to conflict by changes in socio-structural conditions (e.g., resource scarcity, migration). We propose an additional, subtle, and general effect of climate change threat via increases in authoritarian attitudes. Three studies in Germany and the UK support this suggestion. Reminding participants of the adverse consequences climate change may have for their country increased the derogation

Immo Fritsche; J. Christopher Cohrs; Thomas Kessler; Judith Bauer

229

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

NASA Astrophysics Data System (ADS)

"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

Blaschek, Michael; Bakker, Pepijn; Renssen, Hans

2013-04-01

230

Expansion of global drylands under a warming climate  

NASA Astrophysics Data System (ADS)

Global drylands encompassing hyper-arid, arid, semiarid, and dry subhumid areas cover about 41 percent of the earth's terrestrial surface and are home to more than a third of the world's population. By analyzing observations for 1948-2008 and climate model simulations for 1948-2100, we show that global drylands have expanded in the last sixty years and will continue to expand in the 21st~century. By the end of this century, the world's drylands (under a high greenhouse gas emission scenario) are projected to be 5.8 × 106 km2 (or 10%) larger than in the 1961-1990 climatology. The major expansion of arid regions will occur over southwest North America, the northern fringe of Africa, southern Africa, and Australia, while major expansions of semiarid regions will occur over the north side of the Mediterranean, southern Africa, and North and South America. The global dryland expansions will increase the population affected by water scarcity and land degradations.

Feng, S.; Fu, Q.

2013-10-01

231

Cold ecosystems in a warmer climate: carbon fluxes at the alpine treeline under experimental soil warming  

NASA Astrophysics Data System (ADS)

The impact of climatic warming on the C balance of terrestrial ecosystems is uncertain because rising temperature increases both C gains through net primary production, but also respiratory C losses. 'Cold' ecosystems such as treeline ecotones will respond particularly sensitive to climatic changes because many processes are limited by temperature and soils store particular large amounts of labile soil organic matter. In our study, we investigate ecosystem responses to 9 years of elevated atmospheric CO2 and to 3 years of experimental soil warming by 4° C. The added CO2 contains another ?13C signature than normal air, which allows the tracing of new carbon through the plant and soil system. This provides new insight into carbon cycling at the treeline and it shows which C flux respond most sensitive to climatic changes. Results showed that soil warming increased soil CO2 effluxes instantaneously and persisted for at least three vegetation periods (+35-45%; +80 to 120 g C m y-1). In contrast, DOC leaching showed a negligible response of less than 5% increase. Annual C uptake of new shoots was not significantly affected by elevated soil temperatures, with a 10 to 20% increase for larch, pine, and dwarf shrubs, respectively, resulting in an overall increase in net C uptake by plants of 20 to 40 g C m-2y-1. The Q10 of 3.0 measured for soil respiration did not change compared to a three-year period before the warming treatment started, suggesting little impact of warming-induced lower soil moisture (-15% relative decrease) or a depletion in labile soil C. The fraction of recent plant-derived C in soil respired CO2 from warmed soils was smaller than that from control soils (25 vs. 40% of total C respired), which implies that the warming-induced increase in soil CO2 efflux resulted mainly from mineralization of older SOM rather than from stimulated root respiration. In summary, the 4 ° C soil warming led to C losses from the studied alpine treeline ecosystem by increasing SOM decomposition more than C gains through plant growth.

Wipf, Sonja; Hagedorn, Frank; Martin, Melissa

2010-05-01

232

Correlation between recruitment and fall condition of age-0 pollock (Theragra chalcogramma) from the eastern Bering Sea under varying climate conditions  

NASA Astrophysics Data System (ADS)

Fishery managers require an understanding of how climate influences recruitment if they are to separate the effects of fishing and climate on production. The southeastern Bering Sea offers opportunities to understand climate effects on recruitment because inter-annual oscillations in ice coverage set up warm or cold conditions for juvenile fish production. Depth-averaged temperature anomalies in the Bering Sea indicate the past nine years have included three warm (2003-2005), an average (2006), and five cold (2007-2011) years. We examined how these climatic states influenced the diet quality and condition (size, energy density and total energy) of young-of-the-year (YOY) pollock (Theragra chalcogramma) in fall. The implications of fall condition were further examined by relating condition prior to winter to the number of age-1 recruits-per-spawner the following summer (R/S). The percentage of lipid in pollock diets was threefold higher in cold years compared with warm years, but stomach fullness did not vary. Consequently, fish energy densities were 33% higher in cold years (P<0.001) than in warm years. In contrast, neither fish size (P=0.666), nor total energy (P=0.197) varied with climatic condition. However, total energy was significantly (P=0.007) and positively correlated with R/S (R2=0.736). We conclude that recruitment to age-1 in the southeastern Bering Sea is improved under environmental conditions that produce large, energy dense YOY pollock in fall.

Heintz, Ron A.; Siddon, Elizabeth C.; Farley, Edward V.; Napp, Jeffrey M.

2013-10-01

233

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

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

234

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

PubMed Central

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

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

2010-01-01

235

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

PubMed

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

Crabbe, M James C

2008-10-01

236

Response of the Arabian Sea to global warming and associated regional climate shift.  

PubMed

The response of the Arabian Sea to global warming is the disruption in the natural decadal cycle in the sea surface temperature (SST) after 1995, followed by a secular warming. The Arabian Sea is experiencing a regional climate-shift after 1995, which is accompanied by a five fold increase in the occurrence of "most intense cyclones". Signatures of this climate-shift are also perceptible over the adjacent landmass of India as: (1) progressively warmer winters, and (2) decreased decadal monsoon rainfall. The warmer winters are associated with a 16-fold decrease in the decadal wheat production after 1995, while the decreased decadal rainfall was accompanied by a decline of vegetation cover and increased occurrence of heat spells. We propose that in addition to the oceanic thermal inertia, the upwelling-driven cooling provided a mechanism that offset the CO(2)-driven SST increase in the Arabian Sea until 1995. PMID:19592084

Kumar, S Prasanna; Roshin, Raj P; Narvekar, Jayu; Kumar, P K Dinesh; Vivekanandan, E

2009-12-01

237

Warming Asymmetries due to Surface Turbulent Heat Flux Feedbacks in IPCC AR4 Climate Simulations  

NASA Astrophysics Data System (ADS)

We use the newly developed Climate Feedback Response Analysis Model (CFRAM) to evaluate the coupled atmosphere-surface temperature changes due to the surface latent and sensible heat flux feedbacks in IPCC AR4 climate simulations. The CFRAM enables us to examine the warming patterns due to both feedbacks that directly affect the TOA radiative fluxes and feedbacks that do not, such as evaporation and surface sensible flux feedbacks. We estimate the surface flux feedback patterns from the difference between the 2×CO2 and control experiments. The temperature changes attributable to the surface sensible heat flux feedback are positive over the ocean with maximum values over the southern ocean and northern hemisphere gulf currents. Over land, the surface sensible heat flux feedback causes a reduction of surface warming over southern Africa, the northeastern part of South America and around the northern hemisphere mid-latitudes, corresponding to a negative feedback. The temperature response attributable to the evaporation feedback is a warming over land with the exception of the equatorial Africa and the mid to high latitudes of the northern hemisphere. Over oceans, the evaporation feedback is negative, causing a reduction of sea surface warming except over the equatorial Pacific Ocean where the evaporation feedback is positive. Overall, the effects of evaporation and surface sensible flux feedbacks tend to cancel one another. The net temperature change patterns in response to total surface flux feedbacks are positive in the mid-latitudes, Arctic region, and equatorial Pacific, but negative in sub-tropics and over Antarctica.

Castet, C.; Lu, J.; Cai, M.

2007-12-01

238

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

PubMed

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 CO? 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

Yi, Chuixiang; Wei, Suhua; Hendrey, George

2014-01-01

239

Climate warming increases Greenland Ice Sheet surface mass balance variability  

NASA Astrophysics Data System (ADS)

We analyze Greenland Ice Sheet (GIS) surface mass balance (SMB) trends generated by the Community Earth System Model for the time period 1850-2100. In addition to the expected decrease in the mean SMB, our analysis reveals a significant secular increase in temporal, integrated SMB variability. The largest variability increase occurs during the 21st century, and arises primarily from growth of the GIS ablation zone (i.e., a decrease in the accumulation area ratio, AAR) in conjunction with a high ratio of ablation-zone to accumulation-zone specific SMB variability. A secondary cause of the overall variability increase is a rise in specific SMB variability itself in both the accumulation and ablation zones, due to increased accumulation variability and lengthened melt seasons. Simple sensitivity experiments indicate that neither mechanism (decrease in the AAR, and increased specific SMB variability) in isolation is capable of causing the overall increase in integrated SMB variability. However, by exposing more of the ice sheet to high-variability ablation, the decrease in the AAR is about twice as effective as increased specific SMB variability in causing the overall variability increase. Ablation-zone SMB variability is driven largely by variability in summertime melting which is in turn regulated by variability in summertime surface energy fluxes. Broader climate processes that regulate these fluxes will therefore exert increasing control on GIS SMB variability in the future. This future increase in SMB variability can be expected to impact GIS-sourced freshwater fluxes and GIS ice dynamic variability, and may also make it more difficult to diagnose future secular trends in GIS volume.

Fyke, J. G.; Vizcaino, M.; Lipscomb, W. H.; Sacks, W.

2013-12-01

240

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

241

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

NASA Astrophysics Data System (ADS)

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.

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

1990-09-01

242

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

NASA Astrophysics Data System (ADS)

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.

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

243

Students’ conceptions about the greenhouse effect, global warming, and climate change  

Microsoft Academic Search

The purpose of this study was to investigate students’ conceptions of the greenhouse effect, global warming, and climate change.\\u000a The study was descriptive in nature and reflected a cross-age design involving the collection of qualitative data from 51\\u000a secondary students from three different schools in the Midwest, USA. These data were analyzed for content in an inductive\\u000a manner to identify

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

2011-01-01

244

Coherent Transmission: A Technique for Stopping Global Warming and Climate Change  

Microsoft Academic Search

\\u000a “Green ICT” means Information and Communications Technology friendly for the globe. To stop global warming and climate change,\\u000a ICT, with low emission of carbon dioxide thus low consumption of energy, is required. When there was no constraint of low\\u000a energy consumption in communications, one solution for making us happier and more comfortable from the information-transmission\\u000a perspective was to have a

Shinsuke Hara

245

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

Microsoft Academic Search

The present study demonstrates that (1) the simulation of the South American warm season (December–February) climate by an\\u000a atmospheric general circulation model (AGCM) is sensitive to the representation of land surface processes, (2) the sensitivity\\u000a is not confined to the “hot spot” in Amazonia, and (3) upgrading the representation of those processes can produce a significant\\u000a improvement in AGCM performance.

H.-Y. Ma; C. R. Mechoso; Y. Xue; H. Xiao; C.-M. Wu; J.-L. Li; F. De Sales

2011-01-01

246

Long-Term Global Warming Scenarios Computed with an Efficient Coupled Climate Model  

Microsoft Academic Search

We present global warming scenarios computed with an intermediate-complexity atmosphere-ocean-sea ice model which has been extensively validated for a range of past climates (e.g., the Last Glacial Maximum). Our simulations extend to the year 3000, beyond the expected peak of CO2 concentrations. The thermohaline ocean circulation declines strongly in all our scenarios over the next 50 years due to a

Stefan Rahmstorf; Andrey Ganopolski

1999-01-01

247

Effects of simulated climate warming on macrophytes in freshwater microcosm communities  

Microsoft Academic Search

We monitored macrophyte communities (Lagarosiphonmajor, Elodea nuttallii, Potamogeton natans) growing in freshwater microcosms that mimicked north temperate shallow lake and pond environments. The microcosms were subjected to a 2 years simulation of two climate warming regimes (3°C above ambient year-round and 3°C above ambient during the summer-only), in combination with a nutrient addition (eutrophication) treatment and the presence or absence

Dermot Mckee; Keith Hatton; John W Eaton; David Atkinson; Alan Atherton; Ian Harvey; Brian Moss

2002-01-01

248

Impacts of climate warming on lake fish community structure and potential effects on ecosystem function  

Microsoft Academic Search

Fish play a key role in the trophic dynamics of lakes, not least in shallow systems. With climate warming, complex changes\\u000a in fish community structure may be expected owing to the direct and indirect effects of temperature, and indirect effects\\u000a of eutrophication, water-level changes and salinisation on fish metabolism, biotic interactions and geographical distribution.\\u000a We review published and new data

Erik Jeppesen; Mariana Meerhoff; Kerstin Holmgren; Ivan González-Bergonzoni; Franco Teixeira-de Mello; Steven A. J. Declerck; Luc De Meester; Martin Søndergaard; Torben L. Lauridsen; Rikke Bjerring; José Maria Conde-Porcuna; Néstor Mazzeo; Carlos Iglesias; Maja Reizenstein; Hilmar J. Malmquist; Zhengwen Liu; David Balayla; Xavier Lazzaro

2010-01-01

249

Estimated impacts of climate warming on California’s high-elevation hydropower  

Microsoft Academic Search

California’s hydropower system is composed of high and low elevation power plants. There are more than 150 high-elevation\\u000a power plants, at elevations above 1,000 feet (300 m). Most have modest reservoir storage capacities, but supply roughly 74%\\u000a of California’s in-state hydropower. The expected shift of runoff peak from spring to winter due to climate warming, resulting\\u000a in snowpack reduction and increased

Kaveh Madani; Jay R. Lund

2010-01-01

250

Is climate warming more consequential towards poles? The phenology of Lepidoptera in Finland.  

PubMed

The magnitude and direction of phenological shifts from climate warming could be predictably variable across the planet depending upon the nature of physiological controls on phenology, the thermal sensitivity of the developmental processes and global patterns in the climate warming. We tested this with respect to the flight phenology of adult nocturnal moths (3.33 million captures of 334 species) that were sampled at sites in southern and northern Finland during 1993-2012 (with years 2005-2012 treated as an independent model validation data set). We compared eight competing models of physiological controls on flight phenology to each species and found strong support for thermal controls of phenology in 66% of the species generations. Among species with strong thermal control of phenology in both the south and north, the average development rate was higher in northern vs. southern populations at 10 °C, but about the same at 15 and 20 °C. With a 3 °C increase in temperature (approximating A2 scenario of IPPC for 2090-2099 relative to 1980-1999) these species were predicted to advance their phenology on average by 17 (SE ± 0.3) days in the south vs. 13 (±0.4) days in the north. The higher development rates at low temperatures of poleward populations makes them less sensitive to climate warming, which opposes the tendency for stronger phenological advances in the north from greater increases in temperature. PMID:24115266

Valtonen, Anu; Leinonen, Reima; Pöyry, Juha; Roininen, Heikki; Tuomela, Jukka; Ayres, Matthew P

2014-01-01

251

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

PubMed Central

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

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

2014-01-01

252

Climate warming and the carbon cycle in the permafrost zone of the former Soviet Union  

SciTech Connect

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. Climate warming could disrupt the balance between carbon (C) accumulation and decomposition processes within the permafrost zone. Increased temperatures may accelerate the rate of organic matter decomposition. At the same time, the productivity of vegetation may increase in response to warming. To assess the future carbon cycle within the permafrost zone under a climate-warming scenario, it is necessary to quantify present carbon pools and fluxes. The present carbon cycle was assessed on the basis of an ecosystem/ecoregion approach. Under the present climate, the phytomass carbon pool was estimated at 17.0 Giga tons. The mortmass (coarse woody debris) carbon pool was estimated at 16.1 Giga tons. The soil carbon pool, including peatlands, was 139.4 Giga tons. The present rate of carbon turnover was 1.6 Giga tons/yr. (Copyright (c) 1993 by John Wiley and Sons, Ltd.)

Kolchugina, T.P.; Vinson, T.S.

1993-01-01

253

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

PubMed

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

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

2014-01-01

254

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

255

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

E-print Network

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

Bieber, Michael

256

Combined effects of global warming and an Atlantic meridional overturning circulation shutdown on West African and European climate  

NASA Astrophysics Data System (ADS)

We investigate the effects of an Atlantic meridional overturning circulation (AMOC) shutdown, for example, due to an influx of fresh water from Arctic ice sheet melting, in combination with global warming (Intergovernmental Panel on Climate Change's A2 business as normal emissions scenario) on West African and European climate. Shutdown of the AMOC by the end of this century is generally seen as possible but not likely, but Arctic ice is melting more quickly than predicted by global models, and the consequences for climate may be severe and the changes abrupt. A regional climate model with 90-km grid spacing is used to conduct a series of present day and future AMOC shutdown simulations. The present-day control initial surface and lateral boundary conditions are derived from the present day National Center for Environmental Prediction reanalysis 2 (NCEP2). For the future runs we use coupled atmosphere-ocean GCM anomalies generated from the Intergovernmental Panel on Climate Change's Assessment Report 4 (IPCC AR4) A2 business as normal emission scenario experiment and apply them directly to the present day control boundary conditions. An idealized SSTA is derived and applied to the present day SSTs based upon coupled atmosphere/ocean GCM water hosing experiments that force a shutdown of the AMOC, but placed in the context of under global warming, In both the boreal spring and summer months, cooling in the eastern Atlantic due to the AMOC shutdown causes an eastward extension of the North Atlantic subtropical high over Europe and rainfall rates decrease markedly throughout most of Europe. In May and June, rainfall rates decrease by 50-80% over Sahelian Africa as a secondary response to the eastern Atlantic cool SSTs, as dry air is advected southward, associated with enhanced northerly flow. In contrast, the atmospheric response to the SSTA in the North Atlantic over Europe and West Africa is decoupled during the boreal summer months; rainfall over Europe continues to decrease by up to 90%, while precipitation over West Africa is largely attributable to the response of the African monsoon to the global warming signal in the Gulf of Guinea. Along the Guinean coast, rainfall rates actually increase by up to 10%, while over the western Sahel rainfall rates decrease by 40%.

Brown, M. G.; Vizy, E. K.; Cook, K. H.

2011-12-01

257

Evaluation of Laboratory Conditioning Protocols for Warm-Mix Asphalt  

E-print Network

laboratory conditioning procedure for preparing WMA specimens for performance tests, despite being essential for mix performance. Based on previous studies, several candidate conditioning protocols for WMA Laboratory Mixed Laboratory Compacted (LMLC...

Yin, Fan 1990-

2012-10-26

258

Assessing the strength of regional changes in near-surface climate associated with a global warming of 2°C  

Microsoft Academic Search

In this study, the strength of the regional changes in near-surface climate associated with a global warming of 2°C with respect\\u000a to pre-industrial times is assessed, distinguishing between 26 different regions. Also, the strength of these regional climate\\u000a changes is compared to the strength of the respective changes associated with a markedly stronger global warming of 4.5°C.\\u000a The magnitude of

Wilhelm May

2010-01-01

259

Heat-related mortality in a warming climate: projections for 12 u.s. Cities.  

PubMed

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

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

2014-01-01

260

Global warming under old and new scenarios using IPCC climate sensitivity range estimates  

NASA Astrophysics Data System (ADS)

Climate projections for the fourth assessment report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) were based on scenarios from the Special Report on Emissions Scenarios (SRES) and simulations of the third phase of the Coupled Model Intercomparison Project (CMIP3). Since then, a new set of four scenarios (the representative concentration pathways or RCPs) was designed. Climate projections in the IPCC fifth assessment report (AR5) will be based on the fifth phase of the Coupled Model Intercomparison Project (CMIP5), which incorporates the latest versions of climate models and focuses on RCPs. This implies that by AR5 both models and scenarios will have changed, making a comparison with earlier literature challenging. To facilitate this comparison, we provide probabilistic climate projections of both SRES scenarios and RCPs in a single consistent framework. These estimates are based on a model set-up that probabilistically takes into account the overall consensus understanding of climate sensitivity uncertainty, synthesizes the understanding of climate system and carbon-cycle behaviour, and is at the same time constrained by the observed historical warming.

Rogelj, Joeri; Meinshausen, Malte; Knutti, Reto

2012-04-01

261

Long-term climate variations in China and global warming signals  

NASA Astrophysics Data System (ADS)

In this work, the authors analyze the observed long-term variations of seasonal climate in China and then investigate the possible influence of increases in greenhouse gas concentrations on these variations by comparing the observations with the simulations of the second phase of the Coupled Model Intercomparison Project (CMIP2). The long-term variations of precipitation and temperature in China are highly seasonally dependent. The main characteristic of summer precipitation in China is a drying trend in the north and a wetting trend in the central part. The precipitation in winter shows an increasing trend in southern and eastern-central China. Interesting features have also been found in the transitional seasons. In spring, precipitation variations are almost opposite to those in summer. In autumn the precipitation decreases in almost the whole country except for the middle and lower reaches of the Yangtze River Valley. In addition, the seasonality of precipitation has become slightly weaker in recent decades in southern and eastern China. Pronounced warming is observed in the entire country in winter, spring, and autumn, particularly in the northern part of China. In summer a cooling trend in central China is particularly interesting, and cooling (warming) trends generally coexist with wetting (drying) trends. The correlativity between precipitation and temperature variations is weak in spring, autumn, and winter. It has also been found that the long-term climate variations in winter and summer in China may be connected to the warming trend in the sea surface temperature of the Indian Ocean. A comparison between the observed seasonal climate variations and the CMIP2 simulations of 16 models indicates that the observed long-term variations of winter, spring, and autumn temperature in China may be associated with increases in greenhouse gas concentrations. However, such a connection is not found for the summer temperature. The tremendous uncertainties among the models in precipitation simulations make it difficult to link the precipitation variations to global warming.

Hu, Zeng-Zhen; Yang, Song; Wu, Renguang

2003-10-01

262

Runoff sensitivities of major global river basins in a warming climate  

NASA Astrophysics Data System (ADS)

Runoff is a key index of renewable water resources which affect almost all human and natural systems. Any substantial change in runoff therefore has the potential to impact food and freshwater security. We analyze the runoff response to global warming as predicted by climate change experiments generated for the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. In contrast to previous work, we estimate the sensitivity of runoff per degree of global mean temperature change, with the rationale that the global average temperature change is indexed to cumulative global emissions, and therefore removes most of the dependence on emissions scenarios. Our results show that the predicted fractional change in runoff per degree warming is relatively stable across emissions scenarios and global mean temperature increments, but varies substantially across models with the exception of the high-latitudes and currently arid or semi-arid areas. Among the 194 large global river basins studied, the number of basins with decreasing runoff increases by about 12% per degree global temperature increase, and the associated fraction of global land area, effected population, and effected Gross Domestic Product (GDP) increases by about 6, 5, and 8%, respectively. The areas, where the projected runoff decreases more than 10% of the runoff in the period of 1970-1999, cover 13% of the global land area and 20% of the global GDP at a 2 degree C global warming, suggesting substantial expansion of drought area in a warming climate. The estimated runoff elasticity to precipitation ranges from about one to three. The predicted runoff decreases between 2 to 6% per degree local temperature increase over most basins in North America and the middle and high latitudes of Eurasia.

Tang, Q.; Lettenmaier, D. P.

2011-12-01

263

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

USGS Publications Warehouse

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.

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

2009-01-01

264

Warm climates of the past--a lesson for the future?  

PubMed Central

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

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

265

Plant responses to elevated temperatures: a field study on phenological sensitivity and fitness responses to simulated climate warming.  

PubMed

Significant changes in plant phenology have been observed in response to increases in mean global temperatures. There are concerns that accelerated phenologies can negatively impact plant populations. However, the fitness consequence of changes in phenology in response to elevated temperature is not well understood, particularly under field conditions. We address this issue by exposing a set of recombinant inbred lines of Arabidopsis thaliana to a simulated global warming treatment in the field. We find that plants exposed to elevated temperatures flower earlier, as predicted by photothermal models. However, contrary to life-history trade-off expectations, they also flower at a larger vegetative size, suggesting that warming probably causes acceleration in vegetative development. Although warming increases mean fitness (fruit production) by ca. 25%, there is a significant genotype-by-environment interaction. Changes in fitness rank indicate that imminent climate change can cause populations to be maladapted in their new environment, if adaptive evolution is limited. Thus, changes in the genetic composition of populations are likely, depending on the species' generation time and the speed of temperature change. Interestingly, genotypes that show stronger phenological responses have higher fitness under elevated temperatures, suggesting that phenological sensitivity might be a good indicator of success under elevated temperature at the genotypic level as well as at the species level. PMID:24130095

Springate, David A; Kover, Paula X

2014-02-01

266

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

PubMed

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

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

2014-10-01

267

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

USGS Publications Warehouse

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.

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

2013-01-01

268

Earlier wine-grape ripening driven by climatic warming and drying and management practices  

NASA Astrophysics Data System (ADS)

Trends in phenological phases associated with climate change are widely reported--yet attribution remains rare. Attribution research in biological systems is critical in assisting stakeholders to develop adaptation strategies, particularly if human factors may be exacerbating impacts. Detailed, quantified attribution helps to effectively target adaptation strategies, and counters recent tendencies to overattribute phenological trends to climate shifts. Wine grapes have been ripening earlier in Australia in recent years, often with undesirable impacts. Attribution analysis of detected trends in wine-grape maturity, using time series of up to 64 years in duration, indicates that two climate variables--warming and declines in soil water content--are driving a major portion of this ripening trend. Crop-yield reductions and evolving management practices have probably also contributed to earlier ripening. Potential adaptation options are identified, as some drivers of the trend to earlier maturity can be manipulated through directed management initiatives, such as managing soil moisture and crop yield.

Webb, L. B.; Whetton, P. H.; Bhend, J.; Darbyshire, R.; Briggs, P. R.; Barlow, E. W. R.

2012-04-01

269

Accounting for global-mean warming and scaling uncertainties in climate change impact studies Hydrol. Earth Syst. Sci., 11(3), 12071226, 2007  

E-print Network

Accounting for global-mean warming and scaling uncertainties in climate change impact studies 1207(s) 2007. This work is licensed under a Creative Commons License. Accounting for global-mean warming from a few regional climate model runs are scaled, based on different global-mean warming projections

Paris-Sud XI, Université de

270

Probability distributions for regional climate change from uncertain global mean warming and uncertain scaling relationship Hydrol. Earth Syst. Sci., 11(3), 10971114, 2007  

E-print Network

Probability distributions for regional climate change from uncertain global mean warming of probability distributions for regional climate change from uncertain global mean warming and an uncertain/precipitation per degree global mean warming. Each scaling variable is assumed to be normally distributed

Paris-Sud XI, Université de

271

Tittel: An Alternative to the Global Warming Potential for Comparing Climate Impacts of Emissions of Greenhouse Gases Title: An Alternative to the Global Warming Potential for Comparing Climate Impacts of Emissions of Greenhouse Gases  

Microsoft Academic Search

The Global Warming Potential (GWP) is used within the Kyoto Protocol to the United Nations Framework Convention on Climate Change as a metric for weighting the climatic impact of emissions of different greenhouse gases. The GWP has been subject to many criticisms because of its formulation, but nevertheless it has retained some favour because of the simplicity of its design

Keith P. Shine; Jan S. Fuglestvedt; Nicola Stuber

272

Higher precision estimates of regional polar warming by ensemble regression of climate model projections  

NASA Astrophysics Data System (ADS)

This study presents projections of twenty-first century wintertime surface temperature changes over the high-latitude regions based on the third Coupled Model Inter-comparison Project (CMIP3) multi-model ensemble. The state-dependence of the climate change response on the present day mean state is captured using a simple yet robust ensemble linear regression model. The ensemble regression approach gives different and more precise estimated mean responses compared to the ensemble mean approach. Over the Arctic in January, ensemble regression gives less warming than the ensemble mean along the boundary between sea ice and open ocean (sea ice edge). Most notably, the results show 3 °C less warming over the Barents Sea (~7 °C compared to ~10 °C). In addition, the ensemble regression method gives projections that are 30 % more precise over the Sea of Okhostk, Bering Sea and Labrador Sea. For the Antarctic in winter (July) the ensemble regression method gives 2 °C more warming over the Southern Ocean close to the Greenwich Meridian (~7 °C compared to ~5 °C). Projection uncertainty was almost half that of the ensemble mean uncertainty over the Southern Ocean between 30° W to 90° E and 30 % less over the northern Antarctic Peninsula. The ensemble regression model avoids the need for explicit ad hoc weighting of models and exploits the whole ensemble to objectively identify overly influential outlier models. Bootstrap resampling shows that maximum precision over the Southern Ocean can be obtained with ensembles having as few as only six climate models.

Bracegirdle, Thomas J.; Stephenson, David B.

2012-12-01

273

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

SciTech Connect

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.

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

1987-01-01

274

Reproductive and physiological responses to simulated climate warming for four subalpine species.  

PubMed

* The carbon costs of reproduction were examined in four subalpine herbaceous plant species for which number and size of flowers respond differently under a long-term infrared warming experiment. * Instantaneous measurements of gas exchange and an integrative model were used to calculate whole-plant carbon budgets and reproductive effort (RE). * Of the two species for which flowering was reduced, only one (Delphinium nuttallianum) exhibited higher RE under warming. The other species (Erythronium grandiflorum) flowers earlier when freezing events under warming treatment could have damaged floral buds. Of the two species for which flowering rates were not reduced, one (Helianthella quinquenervis) had higher RE, while RE was unaffected for the other (Erigeron speciosus). Each of these different responses was the result of a different combination of changes in organ size and physiological rates in each of the species. * Results show that the magnitude and direction of responses to warming differ greatly among species. Such results demonstrate the importance of examining multiple species to understand the complex interactions among physiological and reproductive responses to climate change. PMID:17176399

Lambrecht, Susan C; Loik, Michael E; Inouye, David W; Harte, John

2007-01-01

275

Modeling the subsurface thermal impact of Arctic thaw lakes in a warming climate  

NASA Astrophysics Data System (ADS)

Warming air temperatures in the Arctic are modifying the rates of thermokarst processes along Alaska's Arctic Coastal Plain. The Arctic Coastal Plain is dominated by thaw lakes. These kilometer-scale lakes are the most visible surface features in the region, and they provide important habitats for migratory birds. The lakes are formed by thermokarst processes, and are therefore susceptible to change as warming continues. We present a 1D numerical model of permafrost and subsidence processes in order to investigate the subsurface thermal impact of thaw lakes of various depths, and to evaluate how this impact might change in a warming climate. Currently, most thaw lakes in the region are shallow (<˜2 m deep), freeze to their base each winter, and are not underlain by permanently unfrozen ground (taliks). Field observations indicate that these shallow lakes have not greatly altered the thermal structure of the subsurface. Our model suggests that under a warming scenario, the number of lakes that do not freeze to their base during the winter, and are therefore underlain by taliks, will increase. Such changes could substantially alter the hydrology of the Arctic Coastal Plain.

Matell, N.; Anderson, R. S.; Overeem, I.; Wobus, C.; Urban, F. E.; Clow, G. D.

2013-04-01

276

Variability of terrestrial carbon cycle and its interaction with climate under global warming  

NASA Astrophysics Data System (ADS)

Land-atmosphere carbon exchange makes a significant contribution to the variability of atmospheric CO2 concentration on time scales of seasons to centuries. In this thesis, a terrestrial vegetation and carbon model, VEgetation-Global-Atmosphere-Soil (VEGAS), is used to study the interactions between the terrestrial carbon cycle and climate over a wide-range of temporal and spatial scales. The VEGAS model was first evaluated by comparison with FLUXNET observations. One primary focus of the thesis was to investigate the interannual variability of terrestrial carbon cycle related to climate variations, in particular to El Nino-Southern Oscillation (ENSO). Our analysis indicates that VEGAS can properly capture the response of terrestrial carbon cycle to ENSO: suppression of vegetative activity coupled with enhancement of soil decomposition, due to predominant warmer and drier climate patterns over tropical land associated with El Nino. The combined affect of these forcings causes substantial carbon flux into the atmosphere. A unique aspect of this work is to quantify the direct and indirect effects of soil wetness vegetation activities and consequently on land-atmosphere carbon fluxes. Besides this canonic dominance of the tropical response to ENSO, our modeling study simulated a large carbon flux from the northern mid-latitudes, triggered by the 1998-2002 drought and warming in the region. Our modeling indicates that this drought could be responsible for the abnormally high increase in atmospheric CO2 growth rate (2 ppm/yr) during 2002-2003. We then investigated the carbon cycle-climate feedback in the 21 st century. A modest feedback was identified, and the result was incorporated into the Coupled Carbon Cycle Climate Model Inter-comparison Project (C4MIP). Using the fully coupled carbon cycle-climate simulations from C4MIP, we examined the carbon uptake in the Northern High Latitudes poleward of 60°N (NHL) in the 21st century. C4MIP model results project that the NHL will be a carbon sink by 2100, as CO2 fertilization and warming stimulate vegetation growth, canceling the effect of enhancement of soil decomposition by warming. However, such competing mechanisms may lead to a switch of NHL from a net carbon sink to source after 2100. All these effects are enhanced as a result of positive carbon cycle-climate feedbacks.

Qian, Haifeng

277

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

PubMed

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

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

2014-11-14

278

The effect of global warming and global cooling on the distribution of the latest Permian climate zones  

Microsoft Academic Search

The end-Permian biotic crisis is commonly associated with rapid and severe climatic changes. These climatic changes are commonly suggested to have originated from solid Earth carbon degassing (leading to global warming), but aerosol- and ash-induced cooling induced by lava degassing has been suggested as well. The application of an Earth System Model of Intermediate Complexity has enabled a visualisation of

Marco Roscher; Frode Stordal; Henrik Svensen

2011-01-01

279

Introduction to special section on The role of the Atlantic warm pool in the climate of the Western Hemisphere  

E-print Network

, and the Atlantic Multidecadal Oscillation can act on, or interact with, the AWP at interannual to multidecadal time study. Climatic phenomena such as the El Niño­Southern Oscillation, the North Atlantic OscillationIntroduction to special section on The role of the Atlantic warm pool in the climate of the Western

280

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

E-print Network

Evidence for 20th century climate warming and wetland drying in the North American Prairie Pothole 20708 Keywords Climate change, cover cycle, hindcasting, North American wetlands, PPR, Prairie Pothole, Brookings, South Dakota 57007 3 U.S. Geological Survey, Patuxent Wildlife Research Center, Laurel, Maryland

281

Changes in permafrost environments along the Qinghai–Tibet engineering corridor induced by anthropogenic activities and climate warming  

Microsoft Academic Search

The sensitive permafrost environments along the Qinghai–Tibet Engineering Corridor (QTEC) from Golmud to Lhasa are controlled by periglacial processes, geography, geocryology and the local climate. During the past 50 years, permafrost has been degrading at a rapid rate due to the combined influences of steadily increasing human activities and persistent climatic warming, and extensive accelerated degradation has been observed along the

Hui-jun Jin; Qi-hao Yu; Shao-ling Wang; Lan-zhi Lü

2008-01-01

282

The Political Economy of Climate Change Mitigation Policies: How to Build a Constituency to Address Global Warming?  

Microsoft Academic Search

Developments over the past few years have shown that reforms to address climate change are no less difficult to implement than reforms in other areas, even if the objective of limiting global warming is broadly accepted. In the case of global public goods such as the climate, the political challenge is further complicated by the need to convince voters that

Alain de Serres; John Llewellyn; Preston Llewellyn

2011-01-01

283

Assessing the combined effect of dams and climate warming on streamflow in California's Sierra Nevada for regional-scale adaptation  

NASA Astrophysics Data System (ADS)

Dams and their operations harm river ecosystems, in part by altering the natural flow regimes that those ecosystems depend on. In the multi-reservoir water management systems of California's Sierra Nevada, greater emphasis is being placed on re-operating existing reservoir systems to recover downstream ecosystems. However, climate change is changing inflow patterns, affecting both ecosystems and traditional water system benefits across the region. As new reservoir operation schemes will be needed to manage for natural resources management objectives at the regional scale, characterizing historical and future environmental impacts of current operations across the region can aid in prioritizing planning efforts. We used a coarse-scale water resources simulation model developed for the western Sierra Nevada to explore the independent and combined effects of dams and climate warming on the flow regime directly below reservoirs, the focal point for instream flow requirements in operations licenses. We quantified changes to mean annual flow, annual low flow duration, annual runoff centroid timing, and weekly rate of decrease under binary combinations of management (unregulated/regulated) and climate (historical/future) conditions. We demonstrate that although rivers in the Sierra Nevada are currently managed in ways that are harmful to instream ecosystems, and that streamflow effects of operations are typically much worse than climate change effects, there are signals that reservoirs can potentially be used to help adapt to some of climate changes harmful effects with little additional effort in some cases. This study is the first step toward a better understanding of the environmental costs from and opportunities afforded by the current stock of reservoirs in a large hydroregion under changing social and environmental conditions.

Rheinheimer, D. E.; Viers, J. H.

2012-12-01

284

Assessing Climate Change Impacts for Military Installations in the Southwest United States During the Warm Season  

NASA Astrophysics Data System (ADS)

Arid and semi-arid regions are experiencing some of the most adverse impacts of climate change with increased heat waves, droughts, and extreme weather. These events will likely exacerbate socioeconomic and political instabilities in regions where the United States has vital strategic interests and ongoing military operations. The Southwest U.S. is strategically important in that it houses some of the most spatially expansive and important military installations in the country. The majority of severe weather events in the Southwest occur in association with the North American monsoon system (NAMS), and current observational record has shown a 'wet gets wetter and dry gets drier' global monsoon precipitation trend. We seek to evaluate the warm season extreme weather projection in the Southwest U.S., and how the extremes can affect Department of Defense (DoD) military facilities in that region. A baseline methodology is being developed to select extreme warm season weather events based on historical sounding data and moisture surge observations from Gulf of California. Numerical Weather Prediction (NWP)-type high resolution simulations will be performed for the extreme events identified from Weather Research and Forecast (WRF) model simulations initiated from IPCC GCM and NCAR Reanalysis data in both climate control and climate change periods. The magnitude in extreme event changes will be analyzed, and the synoptic forcing patterns of the future severe thunderstorms will provide a guide line to assess if the military installations in the Southwest will become more or less susceptible to severe weather in the future.

Castro, C.

2013-05-01

285

Arctic climate change with a 2 ? C global warming: Timing, climate patterns and vegetation change  

Microsoft Academic Search

The signatories to United Nations Framework Convention on Climate Change are charged with stabilizing the concentrations of\\u000a greenhouse gases in the atmosphere at a level that prevents dangerous interference with the climate system. A number of nations,\\u000a organizations and scientists have suggested that global mean temperature should not rise over 2 ?C above preindustrial levels. However, even a relatively moderate

Jed O. Kaplan; Mark New

2006-01-01

286

Climate Extremes Triggered State Shifting of US Great Plains Prairie under Experimental Warming  

NASA Astrophysics Data System (ADS)

Ecosystems can exist under multiple stable states. Transition from one stable state to another is usually triggered by perturbations such as climate extremes, which should be large enough to push the ecosystem over a threshold. Ecosystem state changes can alter ecosystem functions and services as dramatically as in Sahara with vegetation changes from tropical forests to grassland and deserts over 6000 years. Thus it is crucial to understand mechanisms underlying ecosystem state changes. State changes of ecosystem vegetation have been well documented in paleo-records and predicted to occur under climate change by dynamic global vegetation models. Paleo-records usually offer broad-scale patterns of ecosystem state changes over time and rarely offer much insight into fundamental mechanisms underlying the state changes. Model predictions may be calibrated against contemporary and paleo vegetation distributions but have not been carefully tested against experimental evidence. The latter, however, is extremely rare largely because global chance experiments are mostly short term. We have observed state shifting of a US Great Plains prairie under long-term experimental warming and clipping treatments. Our analysis of 11-year data from the experiment showed two-stage stimulations of aboveground net primary production (ANPP) with small increases in the first 7 followed by distinctly large increases under experimental warming in comparison with those under control. The two-stage ANPP simulations were corresponded with species reordering with the plant community over time but not related to warming-induced changes in temperature, soil moisture and nitrogen dynamics in the grassland. The state shifting of the grassland under the experimental warming was partly because our experimental site locates in an ecotone between the mixed and tall grass prairies. Under the experimental warming, the prairie was shifting from the mixed prairie as dominated by Schizachyrium scoparium (little blue stem) with a typical height of about 1 m to a typical tallgrass prairie dominated by Sorghastrum nutans (Indian grass) of about 2 m tall. Our results suggested that chronic experimental treatments differentially exerted impacts on individual species to certain thresholds, beyond which plant community structure and ecosystem functions were changing to a different state. , The threshold change was triggered by climate extremes with two consecutive drought years in 2005 and 2006 followed by a very wet year in 2007.

Luo, Y.; Xu, X.; Sherry, R.; Niu, S.; Li, D.; Xia, J.

2012-04-01

287

Thermal thresholds as predictors of seed dormancy release and germination timing: altitude-related risks from climate warming for the wild grapevine Vitis vinifera subsp. sylvestris  

PubMed Central

Background and Aims The importance of thermal thresholds for predicting seed dormancy release and germination timing under the present climate conditions and simulated climate change scenarios was investigated. In particular, Vitis vinifera subsp. sylvestris was investigated in four Sardinian populations over the full altitudinal range of the species (from approx. 100 to 800 m a.s.l). Methods Dried and fresh seeds from each population were incubated in the light at a range of temperatures (10–25 and 25/10 °C), without any pre-treatment and after a warm (3 months at 25 °C) or a cold (3 months at 5 °C) stratification. A thermal time approach was then applied to the germination results for dried seeds and the seed responses were modelled according to the present climate conditions and two simulated scenarios of the Intergovernmental Panel on Climate Change (IPCC): B1 (+1·8 °C) and A2 (+3·4 °C). Key Results Cold stratification released physiological dormancy, while very few seeds germinated without treatments or after warm stratification. Fresh, cold-stratified seeds germinated significantly better (>80 %) at temperatures ?20 °C than at lower temperatures. A base temperature for germination (Tb) of 9·0–11·3 °C and a thermal time requirement for 50 % of germination (?50) ranging from 33·6 °Cd to 68·6 °Cd were identified for non-dormant cold-stratified seeds, depending on the populations. This complex combination of thermal requirements for dormancy release and germination allowed prediction of field emergence from March to May under the present climatic conditions for the investigated populations. Conclusions The thermal thresholds for seed germination identified in this study (Tb and ?50) explained the differences in seed germination detected among populations. Under the two simulated IPCC scenarios, an altitude-related risk from climate warming is identified, with lowland populations being more threatened due to a compromised seed dormancy release and a narrowed seed germination window. PMID:23071219

Orru, Martino; Mattana, Efisio; Pritchard, Hugh W.; Bacchetta, Gianluigi

2012-01-01

288

Amazon Basin climate under global warming: the role of the sea surface temperature.  

PubMed

The Hadley Centre coupled climate-carbon cycle model (HadCM3LC) predicts loss of the Amazon rainforest in response to future anthropogenic greenhouse gas emissions. In this study, the atmospheric component of HadCM3LC is used to assess the role of simulated changes in mid-twenty-first century sea surface temperature (SST) in Amazon Basin climate change. When the full HadCM3LC SST anomalies (SSTAs) are used, the atmosphere model reproduces the Amazon Basin climate change exhibited by HadCM3LC, including much of the reduction in Amazon Basin rainfall. This rainfall change is shown to be the combined effect of SSTAs in both the tropical Atlantic and the Pacific, with roughly equal contributions from each basin. The greatest rainfall reduction occurs from May to October, outside of the mature South American monsoon (SAM) season. This dry season response is the combined effect of a more rapid warming of the tropical North Atlantic relative to the south, and warm SSTAs in the tropical east Pacific. Conversely, a weak enhancement of mature SAM season rainfall in response to Atlantic SST change is suppressed by the atmospheric response to Pacific SST. This net wet season response is sufficient to prevent dry season soil moisture deficits from being recharged through the SAM season, leading to a perennial soil moisture reduction and an associated 30% reduction in annual Amazon Basin net primary productivity (NPP). A further 23% NPP reduction occurs in response to a 3.5 degrees C warmer air temperature associated with a global mean SST warming. PMID:18267896

Harris, Phil P; Huntingford, Chris; Cox, Peter M

2008-05-27

289

Adaptation to Global Warming: Do Climate Models Tell Us What We Need to Know? Author(s): Naomi Oreskes, David A. Stainforth, Leonard A. Smith  

E-print Network

Adaptation to Global Warming: Do Climate Models Tell Us What We Need to Know? Author(s): Naomi. All rights reserved. 1012 Adaptation to Global Warming: Do Climate Models Tell Us What We Need to Know) for a synthesis of three Intergovernmental Panel on Climate Change (IPCC) working groups. #12;ADAPTATION TO GLOBAL

Stevenson, Paul

290

The toxicology of climate change: environmental contaminants in a warming world.  

PubMed

Climate change induced by anthropogenic warming of the earth's atmosphere is a daunting problem. This review examines one of the consequences of climate change that has only recently attracted attention: namely, the effects of climate change on the environmental distribution and toxicity of chemical pollutants. A review was undertaken of the scientific literature (original research articles, reviews, government and intergovernmental reports) focusing on the interactions of toxicants with the environmental parameters, temperature, precipitation, and salinity, as altered by climate change. Three broad classes of chemical toxicants of global significance were the focus: air pollutants, persistent organic pollutants (POPs), including some organochlorine pesticides, and other classes of pesticides. Generally, increases in temperature will enhance the toxicity of contaminants and increase concentrations of tropospheric ozone regionally, but will also likely increase rates of chemical degradation. While further research is needed, climate change coupled with air pollutant exposures may have potentially serious adverse consequences for human health in urban and polluted regions. Climate change producing alterations in: food webs, lipid dynamics, ice and snow melt, and organic carbon cycling could result in increased POP levels in water, soil, and biota. There is also compelling evidence that increasing temperatures could be deleterious to pollutant-exposed wildlife. For example, elevated water temperatures may alter the biotransformation of contaminants to more bioactive metabolites and impair homeostasis. The complex interactions between climate change and pollutants may be particularly problematic for species living at the edge of their physiological tolerance range where acclimation capacity may be limited. In addition to temperature increases, regional precipitation patterns are projected to be altered with climate change. Regions subject to decreases in precipitation may experience enhanced volatilization of POPs and pesticides to the atmosphere. Reduced precipitation will also increase air pollution in urbanized regions resulting in negative health effects, which may be exacerbated by temperature increases. Regions subject to increased precipitation will have lower levels of air pollution, but will likely experience enhanced surface deposition of airborne POPs and increased run-off of pesticides. Moreover, increases in the intensity and frequency of storm events linked to climate change could lead to more severe episodes of chemical contamination of water bodies and surrounding watersheds. Changes in salinity may affect aquatic organisms as an independent stressor as well as by altering the bioavailability and in some instances increasing the toxicity of chemicals. A paramount issue will be to identify species and populations especially vulnerable to climate-pollutant interactions, in the context of the many other physical, chemical, and biological stressors that will be altered with climate change. Moreover, it will be important to predict tipping points that might trigger or accelerate synergistic interactions between climate change and contaminant exposures. PMID:19375165

Noyes, Pamela D; McElwee, Matthew K; Miller, Hilary D; Clark, Bryan W; Van Tiem, Lindsey A; Walcott, Kia C; Erwin, Kyle N; Levin, Edward D

2009-08-01

291

Icing Conditions Over Northern Eurasia in Changing Climate  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

292

Causes of 15th century warming event in the Arctic in a coupled climate model including data assimilation  

NASA Astrophysics Data System (ADS)

A group of simulations performed over the last millennium with a three-dimensional climate model of intermediate complexity are forced to follow temperature histories obtained from a recent compilation of well- calibrated surface temperature proxies using a simple data assimilation technique. Those simulations provide a reconstruction of the climate of the Arctic that is compatible with model physics, the forcing applied and the proxy records. Available observational data, proxy-based reconstructions and our model results suggest that the Arctic climate is characterized by important variations of temperature over the last millennium. Even though the last decades are likely to be the warmest of the last millennium, other particular warming episodes also took place previously in the Arctic. For instance, the Arctic experienced an important warming during the 1920-1940 period. Temperatures at this time were similar to the recent ones. Likewise, our model reconstructions show a particularly warm period at the end of the 15th century. This warm event is likely related to the internal variability of the climate system rather than being caused by external forcing. We point out the role of the different mechanisms that could have been responsible for the changes during this period and we advance the coherent hypothesis that changes in atmospheric circulation could be the main cause of the Arctic warming during the late 15th century warming period.

Crespin, E.; Goosse, H.; Fichefet, T.; Mann, M. E.

2008-12-01

293

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

PubMed Central

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

Koneswaran, Gowri; Nierenberg, Danielle

2008-01-01

294

Examining Impact of Global warming on the summer monsoon system using regional Climate Model (PRECIS)  

NASA Astrophysics Data System (ADS)

Every year, southwest monsoon arrives over Indian region with remarkable regularity. It hits the southern state of Kerala first by the end of May or the early June. More than 70% of the annual precipitation is received during the four monsoon months viz. June to September. This monsoon rainfall is vital for the agriculture as well as for the yearly needs of Indian population. The performance of the monsoon depends on the timely onset over southern tip of India and its progress along the entire country. This northward progression of monsoon to cover the entire Indian landmass, many times, is associated with the formation of synoptic scale system in the Bay of Bengal region and their movement along the monsoon trough region. The analysis of the observed cyclonic disturbances show that their frequency has reduced in recent decades. It is, therefore, necessary to assess the effect of global warming on the monsoon climate of India. A state-of-art regional climate modelling system, known as PRECIS (Providing REgional Climates for Impacts Studies) developed by the Hadley Centre for Climate Prediction and Research, U.K. is applied over the South Asian domain to investigate the impact of global warming on the cyclonic disturbances. The PRECIS simulations at 50 km x 50 km horizontal resolution are made for two time slices, present (1961-1990) and the future (2071-2100), for two socio-economic scenarios A2 and B2. The model skills are evaluated using observed precipitation and surface air temperature. The model has shown reasonably good skill in simulating seasonal monsoon rainfall, whereas cold bias is seen in surface air temperature especially in post-monsoon months. The typical monsoon features like monsoon trough, precipitation maxima over west coast and northeast India are well simulated by the model. The model simulations under the scenarios of increasing greenhouse gas concentrations and sulphate aerosols are analysed to study the likely changes in the quasi-permanent systems related to the monsoon climate over India viz. monsoon circulation, heat low over northwest India, mean sea level pressures along monsoon trough region, towards the end of the 21st century. The analysis of the model outputs indicate the weakening of monsoon circulation in the future. The mean sea level pressures in head bay of Bengal regions may be higher in future indicating the less frequent cyclonic disturbances in the Bay of Bengal region, under the effect of global warming.

Patwardhan, S. K.; Kundeti, K.; Krishna Kumar, K.

2011-12-01

295

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

PubMed

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

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

2013-01-01

296

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

NASA Astrophysics Data System (ADS)

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-

Blaschek, Michael; Renssen, Hans

2013-04-01

297

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)

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.

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

2012-04-01

298

Effects of active warm up on thermoregulation and intermittent-sprint performance in hot conditions.  

PubMed

This study examined the effects of active warm up on thermoregulatory responses and intermittent-sprint cycle performance in hot conditions (35.5+/-0.6 degrees C, RH 48.7+/-3.4%). Eight trained males performed a 36-min, intermittent-sprint test (IST) after no (WUP 0), 10-min (WUP 10) or 20-min warm up (WUP 20). The IST contained 2-min blocks consisting of a 4-s sprint, 100s active recovery and 20s passive rest. Twice during the IST, there was a repeated-sprint bout (RSB) comprising five, 2-s sprints separated by approximately 20s. There were no significant differences between trials for mean work (3870+/-757 versus 4028+/-562 versus 3804+/-494Jsprint(-1)), peak power (W) or work decrement (%). However, mean work was significantly less in RSB2 than RSB1 for WUP 20 only (P<0.05). Plasma lactate was significantly higher after active warm up (WUP 20=WUP 10>WUP 0; P<0.05), but not significantly different between conditions following either RSB. Rectal temperature (T(re)) was significantly higher after active warm up (37.0+/-0.3 versus 37.3+/-0.3 versus 37.7+/-0.1 degrees C for WUP0, WUP10 and WUP20, respectively) and throughout the IST. The longer active warm up resulted in a greater increase in T(re) and was associated with a decrease in short-term repeated-sprint ability (with incomplete recovery), but not prolonged, intermittent-sprint performance in the heat. As active warm up did not improve performance (<40min), team-sport athletes may minimise changes in T(re) (and the likelihood of heat illness) by avoiding excessive warm up when competing in the heat. PMID:18055260

Bishop, David; Maxwell, Neil S

2009-01-01

299

Historic Trends in U. S. Drought Forcing in a Warming Climate  

E-print Network

The mean North American and world climates have warmed significantly since the beginning of climatologically significant anthropogenic emission of greenhouse gases in the 19th Century. It has been suggested that warming may increase the frequency or severity of droughts. We define and study the statistics of an aridity index that describes the precipitation forcing function of a drought, considering drought to be a season with low enough precipitation to be significant for agriculture. Our aridity index is a reciprocal function of the seasonal precipitation, which is more significant for agriculture than mean precipitation. Using NOAA data from sites in 13 diverse climate regimes in the 48 contiguous United States with time series running over the period 1940--1999 but including two data series from 1900 or 1910, and computing their decadal averages, we search for linear trends in their aridity indices. We find no linear trends significant at the $2\\sigma$ level. At five sites $3\\sigma$ upper bounds on any sy...

Muschinski, T

2014-01-01

300

Responses of butterflies to twentieth century climate warming: implications for future ranges.  

PubMed Central

We analyse distribution records for 51 British butterfly species to investigate altitudinal and latitudinal responses to twentieth century climate warming. Species with northern and/or montane distributions have disappeared from low elevation sites and colonized sites at higher elevations during the twentieth century, consistent with a climate explanation. We found no evidence for a systematic shift northwards across all species, even though 11 out of 46 southerly distributed species have expanded in the northern part of their distributions. For a subset of 35 species, we model the role of climate in limiting current European distributions and predict potential future distributions for the period 2070-2099. Most northerly distributed species will have little opportunity to expand northwards and will disappear from areas in the south, resulting in reduced range sizes. Southerly distributed species will have the potential to shift northwards, resulting in similar or increased range sizes. However, 30 out of 35 study species have failed to track recent climate changes because of lack of suitable habitat, so we revised our estimates accordingly for these species and predicted 65% and 24% declines in range sizes for northern and southern species, respectively. These revised estimates are likely to be more realistic predictions of future butterfly range sizes. PMID:12396492

Hill, J K; Thomas, C D; Fox, R; Telfer, M G; Willis, S G; Asher, J; Huntley, B

2002-01-01

301

Functional traits predict relationship between plant abundance dynamic and long-term climate warming.  

PubMed

Predicting climate change impact on ecosystem structure and services is one of the most important challenges in ecology. Until now, plant species response to climate change has been described at the level of fixed plant functional types, an approach limited by its inflexibility as there is much interspecific functional variation within plant functional types. Considering a plant species as a set of functional traits greatly increases our possibilities for analysis of ecosystem functioning and carbon and nutrient fluxes associated therewith. Moreover, recently assembled large-scale databases hold comprehensive per-species data on plant functional traits, allowing a detailed functional description of many plant communities on Earth. Here, we show that plant functional traits can be used as predictors of vegetation response to climate warming, accounting in our test ecosystem (the species-rich alpine belt of Caucasus mountains, Russia) for 59% of variability in the per-species abundance relation to temperature. In this mountain belt, traits that promote conservative leaf water economy (higher leaf mass per area, thicker leaves) and large investments in belowground reserves to support next year's shoot buds (root carbon content) were the best predictors of the species increase in abundance along with temperature increase. This finding demonstrates that plant functional traits constitute a highly useful concept for forecasting changes in plant communities, and their associated ecosystem services, in response to climate change. PMID:24145400

Soudzilovskaia, Nadejda A; Elumeeva, Tatiana G; Onipchenko, Vladimir G; Shidakov, Islam I; Salpagarova, Fatima S; Khubiev, Anzor B; Tekeev, Dzhamal K; Cornelissen, Johannes H C

2013-11-01

302

Native bees buffer the negative impact of climate warming on honey bee pollination of watermelon crops.  

PubMed

If climate change affects pollinator-dependent crop production, this will have important implications for global food security because insect pollinators contribute to production for 75% of the leading global food crops. We investigate whether climate warming could result in indirect impacts upon crop pollination services via an overlooked mechanism, namely temperature-induced shifts in the diurnal activity patterns of pollinators. Using a large data set on bee pollination of watermelon crops, we predict how pollination services might change under various climate change scenarios. Our results show that under the most extreme IPCC scenario (A1F1), pollination services by managed honey bees are expected to decline by 14.5%, whereas pollination services provided by most native, wild taxa are predicted to increase, resulting in an estimated aggregate change in pollination services of +4.5% by 2099. We demonstrate the importance of native biodiversity in buffering the impacts of climate change, because crop pollination services would decline more steeply without the native, wild pollinators. More generally, our study provides an important example of how biodiversity can stabilize ecosystem services against environmental change. PMID:23704044

Rader, Romina; Reilly, James; Bartomeus, Ignasi; Winfree, Rachael

2013-10-01

303

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

304

Climate model simulations of the observed early-2000s hiatus of global warming  

NASA Astrophysics Data System (ADS)

The slowdown in the rate of global warming in the early 2000s is not evident in the multi-model ensemble average of traditional climate change projection simulations. However, a number of individual ensemble members from that set of models successfully simulate the early-2000s hiatus when naturally-occurring climate variability involving the Interdecadal Pacific Oscillation (IPO) coincided, by chance, with the observed negative phase of the IPO that contributed to the early-2000s hiatus. If the recent methodology of initialized decadal climate prediction could have been applied in the mid-1990s using the Coupled Model Intercomparison Project Phase 5 multi-models, both the negative phase of the IPO in the early 2000s as well as the hiatus could have been simulated, with the multi-model average performing better than most of the individual models. The loss of predictive skill for six initial years before the mid-1990s points to the need for consistent hindcast skill to establish reliability of an operational decadal climate prediction system.

Meehl, Gerald A.; Teng, Haiyan; Arblaster, Julie M.

2014-10-01

305

Can ozone depletion and global warming interact to produce rapid climate change?  

PubMed

The atmosphere displays modes of variability whose structures exhibit a strong longitudinally symmetric (annular) component that extends from the surface to the stratosphere in middle and high latitudes of both hemispheres. In the past 30 years, these modes have exhibited trends that seem larger than their natural background variability, and may be related to human influences on stratospheric ozone and/or atmospheric greenhouse gas concentrations. The pattern of climate trends during the past few decades is marked by rapid cooling and ozone depletion in the polar lower stratosphere of both hemispheres, coupled with an increasing strength of the wintertime westerly polar vortex and a poleward shift of the westerly wind belt at the earth's surface. Annular modes of variability are fundamentally a result of internal dynamical feedbacks within the climate system, and as such can show a large response to rather modest external forcing. The dynamics and thermodynamics of these modes are such that strong synergistic interactions between stratospheric ozone depletion and greenhouse warming are possible. These interactions may be responsible for the pronounced changes in tropospheric and stratospheric climate observed during the past few decades. If these trends continue, they could have important implications for the climate of the 21st century. PMID:10677475

Hartmann, D L; Wallace, J M; Limpasuvan, V; Thompson, D W; Holton, J R

2000-02-15

306

Global Warming: Early Warning Signs  

NSDL National Science Digital Library

This science-based world map depicts the local and regional consequences of global climate change. It identifies direct manifestations of a warming trend (fingerprints), and events that are consistent with the projections for global climate change and are likely to become more frequent and widespread with continued warming (harbingers). These signs are linked to a full description of conditions in that part of the world which indicate warming. A curriculum guide engages students in an exploration of the impacts of global climate change.

307

Plants, birds and butterflies: short-term responses of species communities to climate warming vary by taxon and with altitude.  

PubMed

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

Roth, Tobias; Plattner, Matthias; Amrhein, Valentin

2014-01-01

308

Tangential bending and stretching of thin magnesium alloy sheets in warm conditions  

Microsoft Academic Search

The present work aims at studying the tangential bending process (wiping) and the combined effect of a bending and stretching stress on thin (0.7mm) magnesium alloy (AZ31) sheets when working in warm conditions. The test equipment was designed in order to heat the sheet only in the bending region and to stretch the sheet after the wiping process; it was

G. Palumbo; D. Sorgente; L. Tricarico

2009-01-01

309

Climate hotspots: key vulnerable regions, climate change and limits to warming  

Microsoft Academic Search

Defining and operationalizing Article 2 of the UNFCCC remains a challenge. The question of what is dangerous climate change\\u000a is not a purely scientific one, as danger necessarily has a subjective dimension and its definition requires judgment and\\u000a precaution. The papers in this special issue of Regional Environmental Change attempt to navigate this problem, by offering\\u000a an overview of the

William L. Hare; Wolfgang Cramer; Michiel Schaeffer; Antonella Battaglini; Carlo C. Jaeger

2011-01-01

310

BVOCs emission in a semi-arid grassland under climate warming and nitrogen deposition  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (BVOCs) profoundly affect atmospheric chemistry and ecosystem functioning. BVOCs emission and their responses to global change are still unclear in grasslands, which cover one quarter of the Earth's land surface and are currently undergoing the largest changes. Over two growing seasons, we conducted a field experiment in a semi-arid grassland (Inner Mongolia, China) to examine the emission and the responses of BVOCs emissions to warming and nitrogen deposition. The natural emission rate (NER) of monoterpene (dominant BVOCs here) is 107 ± 16 ?g m-2 h-1 in drought 2007, and 266 ± 53 ?g m-2 h-1 in wet 2008, respectively. Warming decreased the standard emission factor (SEF) by 24% in 2007, while increased it by 43% in 2008. The exacerbated soil moisture loss caused by warming in dry season might be responsible for the decrease of SEF in 2007. A possible threshold of soil moisture (8.2% (v/v)), which controls the direction of warming effects on monoterpene emission, existed in the semiarid grassland. Nitrogen deposition decreased the coverage of Artemisia frigida and hence reduced the NER by 24% across the two growing seasons. These results suggest that the grasslands dominated by the extended Artemisia frigida are an important source for BVOCs, while the responses of their emissions to global changes are more uncertain since they depend on multifactorial/in-situ/conditions.

Wang, H. J.; Xia, J. Y.; Mu, Y. J.; Nie, L.; Han, X. G.; Wan, S. Q.

2012-01-01

311

BVOCs emission in a semi-arid grassland under climate warming and nitrogen deposition  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (BVOCs) profoundly affect atmospheric chemistry and ecosystem functioning. BVOCs emission and their responses to global change are still unclear in grasslands, which cover one quarter of the Earth's land surface and are currently undergoing the largest changes. Over two growing seasons, we conducted a field experiment in a semi-arid grassland (Inner Mongolia, China) to examine the emission and the responses of BVOCs emissions to warming and nitrogen deposition. The natural emission rate (NER) of monoterpene (dominant BVOCs here) is 107 ± 16 ?g m-2 h-1 in drought 2007, and 266 ± 53 ?g m-2 h-1 in wet 2008, respectively. Warming decreased the standard emission factor (SEF) by 24% in 2007, while it increased by 43% in 2008. The exacerbated soil moisture loss caused by warming in dry season might be responsible for the decrease of SEF in 2007. A possible threshold of soil moisture (8.2% (v/v)), which controls the direction of warming effects on monoterpene emission, existed in the semiarid grassland. Nitrogen deposition decreased the coverage of Artemisia frigida and hence reduced the NER by 24% across the two growing seasons. These results suggest that the grasslands dominated by the extended Artemisia frigida are an important source for BVOCs, while the responses of their emissions to global changes are more uncertain since they depend on multifactorial in-situ conditions.

Wang, H. J.; Xia, J. Y.; Mu, Y. J.; Nie, L.; Han, X. G.; Wan, S. Q.

2012-04-01

312

Variability in Eastern North American surface ozone under climate warming scenarios: Key role for jet position  

NASA Astrophysics Data System (ADS)

Climate warming is generally expected to degrade air quality in many polluted regions. Model estimates of the magnitude, and in some cases the sign, of the surface ozone response to projected warming, however, disagree regionally. These discrepancies underscore a need for improved process-level understanding of the factors controlling the regional ozone response to warming. Furthermore, developing accurate approaches to estimate regional surface ozone changes directly from projected changes in regional climate requires this process understanding. Over Eastern North America, synoptic variability is known to be a key driver of summertime ozone pollution episodes. We investigate the hypothesis that this variability depends on the position of the jet within this region by analyzing June-August (JJA) daily surface ozone in a suite of CMIP5 and related sensitivity simulations from 1860 to 2100 in the GFDL CM3 chemistry-climate model. Specifically, we use the CM3 CMIP5 Historical (1860-2005; 5-member) and RCP4.5 (2006-2100; 3-member) ensemble simulations. An additional scenario with evolving well-mixed greenhouse gases following the RCP4.5 scenario but emissions of aerosol and ozone precursors held constant at 2005 levels, denoted RCP4.5*, enables us to isolate the impact of climate warming alone from the impact of large decreases in ozone precursor emissions occurring under RCP4.5. We demonstrate that the daily variability of JJA surface ozone is a strong function of the position of the jet-stream over Eastern North America in all three scenarios. The jet stream moves poleward with climate change under the RCP4.5 and RCP4.5* scenarios, and we show that ozone variability follows the position of the jet. The consistent response in both the RCP4.5 and RCP4.5* simulations demonstrates that the large decreases in ozone precursor emissions under RCP4.5 (North American nitrogen oxides (NOx) decrease by about a factor of 5 over the 21st century) are not driving the northward shift of ozone variability. While the relationship with jet latitude remains, the decrease in ozone precursor emissions under RCP4.5 leads to a reduction in variability over the entire region. We further show that the strength of the correlation between ozone and temperature is a strong function of the jet position. The quantitative relationship (slope between ozone and temperature), however, depends strongly on NOx emissions, consistent with recent observation-based work. These findings demonstrate that historical relationships between surface ozone and meteorological quantities such as temperature are unlikely to apply in the future. Although this study focuses solely on Eastern North America, the relationships found here are likely also present in other mid-latitude regions influenced by the mid-latitude jet. The strong dependence of surface ozone variability on jet latitude, a quantity easily computed from climate models, implies that understanding future changes in jet location can be used to derive changes in summertime surface ozone variability and the ozone-temperature correlation. Our results further imply that inter-model discrepancies in jet location likely contribute to the wide range of current estimates for changes in surface ozone in northern mid-latitude regions.

Barnes, Elizabeth; Fiore, Arlene

2013-04-01

313

Variability in Eastern North American surface ozone under climate warming scenarios: Key role for jet position  

NASA Astrophysics Data System (ADS)

Climate warming is generally expected to degrade air quality in many polluted regions. Model estimates of the magnitude, and in some cases the sign, of the surface ozone response to projected warming, however, disagree regionally. These discrepancies underscore a need for improved process-level understanding of the factors controlling the regional ozone response to warming. Furthermore, developing accurate approaches to estimate regional surface ozone changes directly from projected changes in regional climate requires this process understanding. Over Eastern North America, synoptic variability is known to be a key driver of summertime ozone pollution episodes. We investigate the hypothesis that this variability depends on the position of the jet within this region by analyzing June-August (JJA) daily surface ozone in a suite of CMIP5 and related sensitivity simulations from 1860 to 2100 in the GFDL CM3 chemistry-climate model. Specifically, we use the CM3 CMIP5 Historical (1860-2005; 5-member) and RCP4.5 (2006-2100; 3-member) ensemble simulations. An additional scenario with evolving well-mixed greenhouse gases following the RCP4.5 scenario but emissions of aerosol and ozone precursors held constant at 2005 levels, denoted RCP4.5*, enables us to isolate the impact of climate warming alone from the impact of large decreases in ozone precursor emissions occurring under RCP4.5. We demonstrate that the daily variability of JJA surface ozone is a strong function of the position of the jet-stream over Eastern North America in all three scenarios. The jet stream moves poleward with climate change under the RCP4.5 and RCP4.5* scenarios, and we show that ozone variability follows the position of the jet. The consistent response in both the RCP4.5 and RCP4.5* simulations demonstrates that the large decreases in ozone precursor emissions under RCP4.5 (North American nitrogen oxides (NOx) decrease by about a factor of 5 over the 21st century) are not driving the northward shift of ozone variability. While the relationship with jet latitude remains, the decrease in ozone precursor emissions under RCP4.5 leads to a reduction in variability over the entire region. We further show that the strength of the correlation between ozone and temperature is a strong function of the jet position. The quantitative relationship (slope between ozone and temperature), however, depends strongly on NOx emissions, consistent with recent observation-based work. These findings demonstrate that historical relationships between surface ozone and meteorological quantities such as temperature are unlikely to apply in the future. Although this study focuses solely on Eastern North America, the relationships found here are likely also present in other mid-latitude regions influenced by the mid-latitude jet. The strong dependence of surface ozone variability on jet latitude, a quantity easily computed from climate models, implies that understanding future changes in jet location can be used to derive changes in summertime surface ozone variability and the ozone-temperature correlation. Our results further imply that inter-model discrepancies in jet location likely contribute to the wide range of current estimates for changes in surface ozone in northern mid-latitude regions.

Barnes, E. A.; Fiore, A. M.

2012-12-01

314

Does climate warming stimulate or inhibit soil protist communities? A test on testate amoebae in high-arctic tundra with free-air temperature increase.  

PubMed

Soil testate amoebae assemblages in a grassland area at Zackenberg (Northeast Greenland) were subjected to simulated climate-warming during the growing season using the Free-Air Temperature Increase technique. Samples were collected in upper (0 - 3cm) and deeper (3 - 6cm) soil horizons. Mean temperature elevations at 2.5 and 7.5 cm depth were 2.58 ± SD 1.11 and 2.13±SD 0.77°C, respectively, and did not differ significantly. Soil moisture in the top 11cm was not affected by the warming. During the manipulation, the densities of living amoebae and empty shells were higher in the experimental plots but only in the upper layer. Possibly, testate amoebae in the deeper layer were limited by other factors, suggesting that warming enhances the carrying capacity only in favourable conditions. Species richness, on the other hand, was only increased in the deeper horizon. Warming did not change the percentage of individuals belonging to small-sized species in any of the living assemblages, contrary to our expectation that those species would quickly increase their density. However, in the empty shell assemblages, the proportion of small-sized individuals in the experimental plots was higher in both layers, indicating a rapid, transient increase in small amoebae before the first sampling date. Changes in successional state of testate amoebae assemblages in response to future climate change might thus be ephemeral, whereas alterations in density and species richness might be more sustained. PMID:20708962

Tsyganov, Andrey N; Nijs, Ivan; Beyens, Louis

2011-04-01

315

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)

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.

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

2002-12-01

316

Study of a Zirconium Modified 2014 Aluminum Alloy: Analysis of the Best Warm Forming Conditions  

Microsoft Academic Search

The warm forming plasticity conditions of a Zr modified 2014 aluminum alloy has been widely studied in the present work. The microstructure of the material was analysed by TEM in the as-received and as-deformed conditions. Torsion tests were performed in the temperature and strain rate ranges of 250–300 °C and 10?3-1 s?1 respectively. The effect of Zr stabilization on material

Pasquale Cavaliere

317

A Mechanism for Land-Ocean Contrasts in Global Monsoon Trends in a Warming Climate  

NASA Astrophysics Data System (ADS)

A central paradox of the modern global monsoon record involves reported decreases in rainfall over land in an environment in which the global hydrologic cycle is both expected and observed to intensify. Perhaps equally confounding are projections of annual mean tropical convection, which exhibits disproportionate strengthening over ocean. This work develops a physical basis for understanding both the observed record of the global monsoon and its anticipated changes in a warming climate. In doing so it bolsters the concept of a global monsoon in the context of common feedbacks. The global monsoon record across multiple reanalyses is first assessed. Identifiably spurious trends are identified in all reanalysis products and these are linked to changes in their assimilated data streams, both prior to and during the satellite era. The confidence in reported trends in the global monsoon based on reanalyses is thus deemed to be low. Simulated trends in the global monsoon from the CMIP3 archive are then assessed and their land-ocean contrasts are found to agree qualitatively with recent studies using satellite retrievals of rainfall. A feedback mechanism is proposed to explain the contrast that is rooted in the facts that 1) land areas warm disproportionately relative to ocean in a warming climate, and 2) that onshore flow is the chief source of monsoonal moisture. The inextricable consequence of these facts is that, for a fixed mass flow, the increase in oceanic moisture advection is constrained by the rise saturated humidity over ocean. Over land, as a consequence of greater warming, the increase in saturated humidity will be considerably greater. Reductions in lower tropospheric relative humidity (RH) over land monsoon domains associated with this mechanism are therefore inevitable. Reduced RH has direct consequences for convection including a raising of the lifting condensation level and a shift in the distribution of convection generally towards less frequent and potentially more intense events. Cloud amount and the frequency of rainfall are thus expected to decrease, though the total rainfall may increase arising from increases in specific humidity and convective instability. Competition with neighboring ocean regions, where increases in CAPE are disproportionately large relative to land, further augments the contrast. Manifestations of the mechanism are demonstrated to be robust across the CMIP3 archive and thus their existence is not owed to an individual model's treatment of convection or clouds. The mechanism is interpreted as an important modulating influence on the "rich-get-richer" mechanism advanced by previous works. Regional contrasts in the mechanism are discussed.

Fasullo, J.

2011-12-01

318

Tropical Cyclone Climatology in a Global-Warming Climate as Simulated in a 20 km-Mesh Global Atmospheric Model: Frequency and Wind Intensity Analyses  

Microsoft Academic Search

Possible changes in the tropical cyclones in a future, greenhouse-warmed climate are investigated using a 20 km-mesh, high-resolution, global atmospheric model of MRI\\/JMA, with the analyses focused on the evaluation of the frequency and wind intensity. Two types of 10-year climate experiments are conducted. One is a present-day climate experiment, and the other is a greenhouse-warmed climate experiment, with a

Kazuyoshi OOUCHI; Jun YOSHIMURA; Hiromasa YOSHIMURA; Ryo MIZUTA; Shoji KUSUNOKI; Akira NODA

2006-01-01

319

Spatial variability and its scale dependency of observed and modeled soil moisture under different climate conditions  

NASA Astrophysics Data System (ADS)

Past studies on soil moisture spatial variability have been mainly conducted in catchment scales where soil moisture is often sampled over a short time period. Because of limited climate and weather conditions, the observed soil moisture often exhibited smaller dynamic ranges which prevented the complete revelation of soil moisture spatial variability as a function of mean soil moisture. In this study, spatial statistics (mean, spatial variability and skewness) of in situ soil moisture measurements (from a continuously monitored network across the US), modeled and satellite retrieved soil moisture obtained in a warm season (198 days) were examined at large extent scales (>100 km) over three different climate regions. The investigation on in situ measurements revealed that their spatial moments strongly depend on climates, with distinct mean, spatial variability and skewness observed in each climate zone. In addition, an upward convex shape, which was revealed in several smaller scale studies, was observed for the relationship between spatial variability of in situ soil moisture and its spatial mean across dry, intermediate, and wet climates. These climate specific features were vaguely or partially observable in modeled and satellite retrieved soil moisture estimates, which is attributed to the fact that these two data sets do not have climate specific and seasonal sensitive mean soil moisture values, in addition to lack of dynamic ranges. From the point measurements to satellite retrievals, soil moisture spatial variability decreased in each climate region. The three data sources all followed the power law in the scale dependency of spatial variability, with coarser resolution data showing stronger scale dependency than finer ones. The main findings from this study are: (1) the statistical distribution of soil moisture depends on spatial mean soil moisture values and thus need to be derived locally within any given area; (2) the boundedness of soil moisture plays a pivoting role in the dependency of soil moisture spatial variability/skewness on its mean (and thus climate conditions); (3) the scale dependency of soil moisture spatial variability changes with climate conditions.

Li, B.; Rodell, M.

2012-09-01

320

Forest Dynamics and Their Phenological Response to Climate Warming in the Khingan Mountains, Northeastern China  

PubMed Central

The Khingan Mountain region, the most important and typical natural foci of tick-borne encephalitis (TBE) in China, is the largest and northernmost forest area and the one more sensitive to climate change. Taking this region as the study area, we investigated the spatio-temporal dynamics of deciduous broadleaf forest (DBF) and its phenology changes in relation to climate change and elevation. Based on MODIS Enhanced Vegetation Index (EVI) time series over the period of 2001 to 2009, the start-of-season (SOS), length-of-season (LOS) and another two vegetation variables (seasonal amplitude (SA) and integrated EVI (SI)) were derived. Over the past decade, the DBF in Khingan Mountains has generally degraded and over 65% of DBF has experienced negative SA and SI trends. Earlier trends in SOS and longer trends in LOS for DBF were observed, and these trends were mainly caused by climate warming. In addition, results from our analysis also indicated that the effects of temperature on DBF phenology were elevation dependent. The magnitude of advancement in SOS and extension in LOS with temperature increase significantly increased along a raising elevation gradient. PMID:23202825

Cai, Hongyan; Zhang, Shuwen; Yang, Xiaohuan

2012-01-01

321

Temporal trends of mercury in Greenland ringed seal populations in a warming climate.  

PubMed

Temporal trends of mercury in livers of ringed seals collected from the early 1980s to 2010 from central West, Northwest and central East Greenland were studied. In this period the climate of Greenland warmed and the influences of climate indices such as ice coverage, water temperature and the Atlantic Oscillation Index on mercury concentration were evaluated using multiple regressions and Akaike's Information Criteria (AIC) to determine the most parsimonious models. Biological co-variables such as age, sex and trophic position (as determined by stable isotope analysis) of seals were also evaluated. Increasing levels of mercury in seals were found in Ittoqqortoormiit, central East Greenland, and Avanersuaq, Northwest Greenland, with an annual increase of +10.3 and +2%, respectively. Age was an important co-variable for all three regions and trophic position for two regions. The Atlantic Oscillation Index was also an important explanatory variable for all three regions and was positively associated with mercury concentrations in seals indicating the importance of global climatic processes on ringed seal populations in Greenland. PMID:23152143

Rigét, Frank; Dietz, Rune; Hobson, Keith A

2012-12-01

322

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

NASA Astrophysics Data System (ADS)

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.

Goldner, Aaron P.

323

Warm to cold polar climate transitions over the last 15,000 years: A paleoclimatology record from the raised beaches of northern Norway  

SciTech Connect

Because of the strength of the cold, dry arctic high pressure vortex, and the absence of multiple air-mass sources, climate records from the polar region tend to display a cleaner signal than those from mid-latitude settings. The high arctic presents unique opportunities for the prediction of the natural background pattern of climate change prior to the disturbances generated by manmade atmospheric pollutants. The Varanger Peninsula of northernmost Norway was extensively depressed by an ice dome during the last glacial stage. Deglaciation was accompanied by isostatic recovery at a steady though exponentially decaying rate. Superimposed on the rising land is a discontinuous staircase of cobble beach ridges, deposited during the postglacial period by storms at the coast. The ridges are constructed during brief episodes of weather- and tide-related elevation of sea level and wave run-up. Storminess periods can only occur in the absence of sea ice associated with several decades of mild, relatively warm temperatures. A history of local relative sea level is constructed from over 70 radiocarbon dates of various water-level indicators. The sea-level history is used to construct a chronology of beach-ridge building that documents the cyclic, a periodic nature of arctic storminess conditions. The authors date a dynamic signal with multiple climate transitions from warm, stormy conditions to cool, calm conditions occurring roughly every 200 years between 15,000 years ago to 10,000 years ago. Throughout the Holocene the climate is more settled with longer periods separating the major warm to cool transitions.

Fletcher, C.H. (Univ. of Hawaii, Honolulu (United States)); Fairbridge, R.H. (NASA-Goddard Inst. for Space Studies, New York, NY (United States)); Moeller, J.K. (Univ. of Tromso (Norway)); Long, A.J. (Univ. of Durham (United Kingdom))

1991-03-01

324

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

325

Conditional Uncertainty in Anthropogenic Global Climate Change  

NASA Astrophysics Data System (ADS)

Although, the uncertainty associated with human-induced climate change is less that in many other human activities such as economic management and warfare, the uncertainties in the climate system have assumed a disproportionate profile in public debate. Achieving improved public understanding is dependent on consistent use of the various categories of change and their respective uncertainties. Probably the most important distinction to be made is between uncertainties associated with uncertain societal choices and uncertainties associated with the consequences of such choices. For the biogeochemical system, categories of uncertainty are adapted from those used in the study of uncertainty for the REgional Carbon Assessment and Processes (RECCAP) study. These are then extended and applied to the discussion of the combined carbon-climate system. Characterising uncertainties in future change requires a consistent approach to propagating into the future the uncertainties associated with the past and present state of the climate system. Again, previous analysis for the carbon system is extended to the carbon-climate system. The potential category ambiguities that arise from feedbacks between climate and carbon are identified and resolved. A consistent characterisation of the uncertainties in the earth system provides a basis for factoring the overall uncertainty into human and natural contributions.

Enting, I. G.

2012-12-01

326

Can warm climate-related structure of littoral predator assemblies weaken the clear water state in shallow lakes?  

Microsoft Academic Search

Shallow lakes, the most abundant lake type in the world, are very sensitive to climatic changes. The structure and functioning of shallow lakes are greatly impacted by sub- merged plants, and these may be affected by climate warming in various, contrasting, ways. Following a space-for-time substitution approach, we aimed to analyse the role of aquatic (submerged and free-floating) plants in

J UAN; CARLOS I GLESIAS; R. P EDERSEN; Ole Worms

2007-01-01

327

CO2 radiative forcing and Intertropical Convergence Zone influences on western Pacific warm pool climate over the past 400 ka  

NASA Astrophysics Data System (ADS)

The western Pacific warm pool (WPWP) is an important heat source for the atmospheric circulation and influences climate conditions worldwide. Estimating WPWP sensitivity to past radiative forcing perturbations is important for understanding the magnitudes and patterns of current and projected tropical climate change. Here we present a new Mg/Ca-based sea surface temperature (SST) reconstruction over the past 400 ka from the Bismarck Sea, off Papua New Guinea, along with benthic foraminiferal ?18O records and a transient intermediate complexity earth system model simulation. The Mg/Ca-SST record exhibits a close similarity with atmospheric CO2 content for the whole study period. Our model analysis demonstrates that greenhouse gas forcing is the primary driver for glacial/interglacial SST changes in the entire WPWP region. Mg/Ca-SST in the Bismarck Sea also includes a weaker precessional component, which covaries with reconstructed and simulated local precipitation, and simulated surface currents. We propose that orbitally driven latitudinal shifts of the Intertropical Convergence Zone and oceanic heat advection are responsible for this residual SST variability. On glacial timescales the reconstructed WPWP surface temperature changes over the past 400 ka are highly correlated with East Antarctic air temperature variations. The strong effect of greenhouse gas forcings on both records and on global mean temperature variability allows us to determine a scaling factor of 1-1.5 between reconstructed WPWP temperature anomalies and estimates of the global mean temperature.

Tachikawa, Kazuyo; Timmermann, Axel; Vidal, Laurence; Sonzogni, Corinne; Timm, Oliver Elison

2014-02-01

328

Marine Ecosystem Response to Rapid Climate Warming on the West Antarctic Peninsula (Invited)  

NASA Astrophysics Data System (ADS)

The Palmer, Antarctica LTER builds on meteorological, ocean color and seabird observations since the late 1970s. It occupies annually in summer a regional-scale grid extending 700 km northward from Charcot Island to Anvers Island, and 200 km cross-shelf from the coast to the shelfbreak. In addition to routine CTD profiles and zooplankton tows throughout the grid, the observing system also includes Slocum Glider surveys and thermistor moorings. Geophysical changes include +6C atmospheric warming in winter since 1950, a 20% increase in heat content over the continental shelf since 1990, a surface ocean warming of +1C since 1950, an 83-day reduction in sea ice duration (advance 48 days later, retreat 35 days earlier) over the greater southern Bellingshausen Sea region from 1979-2007, intensification of westerly winds and differential changes in cloudiness. In response to these large changes in the regional climate, the marine ecosystem of the western Peninsula is changing at all trophic levels from diatoms to penguins. Ocean color indicates differential changes in phytoplankton stocks in response to regional decreases in sea ice cover. Surface chlorophyll has declined 89% in the north and increased 67% in the south. Antarctic krill and salps have declined and increased in our study area, respectively. Penguin diet sampling suggests changes in populations or distributions of the Antarctic Silverfish in the Anvers Island vicinity, possibly in response to ocean warming. Adélie penguins have declined 75% from 15000 to <3000 pairs at since 1975 in response to changes in food availability and increased late spring snow accumulation. Changes in pygoscelid penguin breeding populations in the Anvers Island vicinity of the West Antarctic Peninsula

Ducklow, H.; Baker, K. S.; Doney, S. C.; Fraser, B.; Martinson, D. G.; Meredith, M. P.; Montes-Hugo, M. A.; Sailley, S.; Schofield, O.; Sherrell, R. M.; Stammerjohn, S. E.; Steinberg, D. K.

2010-12-01

329

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

NASA Astrophysics Data System (ADS)

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.

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

2010-12-01

330

International potential of IGCC technology for use in reducing global warming and climate change emissions  

SciTech Connect

High efficiency advanced coal-based technologies such as Integrated Gasification Combined Cycle (IGCC) that can assist in reducing CO{sub 2} emissions which contribute to Global Warming and Climate Change are becoming commercially available. U-GAS is an advanced gasification technology that can be used in many applications to convert coal in a high efficiency manner that will reduce the total amount of CO{sub 2} produced by requiring less coal-based fuel per unit of energy output. This paper will focus on the status of the installation and performance of the IGT U-GAS gasifiers which were installed at the Shanghai Cooking and Chemical Plant General located in Shanghai, China. Its use in future IGCC project for the production of power and the benefits of IGCC in reducing CO{sub 2} emissions through its high efficiency operation will be discussed.

Lau, F.S. [Inst. of Gas Technology, Chicago, IL (United States)

1996-12-31

331

Climate warming, marine protected areas and the ocean-scale integrity of coral reef ecosystems.  

PubMed

Coral reefs have emerged as one of the ecosystems most vulnerable to climate variation and change. While the contribution of a warming climate to the loss of live coral cover has been well documented across large spatial and temporal scales, the associated effects on fish have not. Here, we respond to recent and repeated calls to assess the importance of local management in conserving coral reefs in the context of global climate change. Such information is important, as coral reef fish assemblages are the most species dense vertebrate communities on earth, contributing critical ecosystem functions and providing crucial ecosystem services to human societies in tropical countries. Our assessment of the impacts of the 1998 mass bleaching event on coral cover, reef structural complexity, and reef associated fishes spans 7 countries, 66 sites and 26 degrees of latitude in the Indian Ocean. Using Bayesian meta-analysis we show that changes in the size structure, diversity and trophic composition of the reef fish community have followed coral declines. Although the ocean scale integrity of these coral reef ecosystems has been lost, it is positive to see the effects are spatially variable at multiple scales, with impacts and vulnerability affected by geography but not management regime. Existing no-take marine protected areas still support high biomass of fish, however they had no positive affect on the ecosystem response to large-scale disturbance. This suggests a need for future conservation and management efforts to identify and protect regional refugia, which should be integrated into existing management frameworks and combined with policies to improve system-wide resilience to climate variation and change. PMID:18728776

Graham, Nicholas A J; McClanahan, Tim R; MacNeil, M Aaron; Wilson, Shaun K; Polunin, Nicholas V C; Jennings, Simon; Chabanet, Pascale; Clark, Susan; Spalding, Mark D; Letourneur, Yves; Bigot, Lionel; Galzin, René; Ohman, Marcus C; Garpe, Kajsa C; Edwards, Alasdair J; Sheppard, Charles R C

2008-01-01

332

Early Paleogene Arctic terrestrial ecosystems affected by the change of polar hydrology under global warming: Implications for modern climate change at high latitudes  

Microsoft Academic Search

Our understanding of both the role and impact of Arctic environmental changes under the current global warming climate is\\u000a rather limited despite efforts of improved monitoring and wider assessment through remote sensing technology. Changes of Arctic\\u000a ecosystems under early Paleogene warming climate provide an analogue to evaluate long-term responses of Arctic environmental\\u000a alteration to global warming. This study reviews Arctic

Qin Leng; Gaytha A. Langlois; Hong Yang

2010-01-01

333

Evaluating indicators for the relative responsibility for climate change - alternatives to the Brazilian proposal and global warming potentials  

Microsoft Academic Search

In this paper, several indicators to describe the responsibility for climate change are discussed and evaluated. During the negotiations of the Kyoto Protocol, the delegation of Brazil proposed to use the impact of historical emissions on the current temperature. The Kyoto Protocol uses current emissions weighted by 100-year global warming potentials (GWPs) as the basis. As a powerful indicator historical

N. Höhne; J. Harnisch

2002-01-01

334

Potential Loss of Thermal Habitat for Brook Trout, Due to Climatic Warming, in Two Southern Ontario Streams  

Microsoft Academic Search

I calibrated a hydrometeorological model of stream temperature to two southern Ontario streams in the summer to estimate potential reductions, due to climatic warming, of thermal habitat for brook trout Salvelinus fontinalis. Summer habitat for brook trout in both streams, determined from electrofishing surveys during 1987 and 1988, was delimited downstream by a thermal barrier of about 24°C. Tagging data

J. Donald Meisner

1990-01-01

335

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

SciTech Connect

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.

Malini, B.H. [Andhra Univ., Visakhapatnam (India)

1997-12-31

336

Characterisation of AZ31B magnesium alloy formability in warm forming conditions  

Microsoft Academic Search

Nowadays, magnesium alloys materials are more and more utilised in transportation industry in order to reduce the vehicles\\u000a mass, and thus to minimize air pollution and fuel consumption. Since they present a quite low formability at room temperature,\\u000a promising applications are developing in the area of sheet metal working in warm temperature conditions. The paper presents\\u000a a complete characterisation of

G. Ambrogio; C. Bruni; S. Bruschi; L. Filice; A. Ghiotti; M. Simoncini

2008-01-01

337

Air bending of AZ31 magnesium alloy in warm and hot forming conditions  

Microsoft Academic Search

The effect of the process parameters on springback of AZ31 magnesium alloy was investigated by performing air bending tests under warm and hot forming conditions. To this purpose, air bending experiments were carried out in the temperature range varying from 100 to 400°C, with different values of the punch speed (0.45 and 4.5mm\\/s). Also the influence of the punch radius

C. Bruni; A. Forcellese; F. Gabrielli; M. Simoncini

2006-01-01

338

Formability of AZ31 magnesium alloy sheets at warm working conditions  

Microsoft Academic Search

Fine-grained AZ31 magnesium alloy sheets were prepared through hot-rolling process. To investigate the mechanical properties of the sheets, uniaxial tensile tests were conducted at various temperatures and strain rates. The formability of AZ31 alloy sheets at warm working conditions was evaluated by limit drawing ratio (LDR) tests and limit dome height (LDH) tests at temperatures from 50 to 240°C. It

K. F. Zhang; D. L. Yin; D. Z. Wu

2006-01-01

339

Do variations in the ?13C of soil phospholipid fatty acids indicate changes in substrate use with climate warming?  

NASA Astrophysics Data System (ADS)

The effect of climate warming on the microbial mineralization of soil organic carbon (SOC) remains a key uncertainty in biogeochemical models. In particular, it remains unclear whether microbial substrate use patterns change with climate. The carbon isotopic signature (?13C) of soil microbial phospholipid fatty acids (?13CPLFA) can provide insight into substrate utilization patterns in situ without manipulations unavoidable in soil incubation experiments. The interpretation of ?13CPLFA, however, is limited by gaps in our understanding of the isotopic fractionation associated with PLFA biosynthesis, and in particular, whether this fractionation changes with growth temperature. Characterizing the principles controlling ?13CPLFA under controlled laboratory conditions can help with the interpretation of field measurements of temperature effects on microbial SOC assimilation. We measured ?13CPLFA from field soils in two regions along a boreal climate transect, which differ by 4.5 °C mean annual temperature. In each region, the organic (L, F, H) and mineral (B; top 10cm) soil horizons were sampled at three locations chosen for similar vegetation (balsam fir), stand age, elevation, and soil type (humo-ferric podzol). Soils from both regions had similar bulk SOC ?13C and exhibited an increase with depth from -29.5±0.4 to -26.5±0.6o. Despite the similar ?13C of SOC, PLFA in the organic horizons from the warmer region were more enriched in 13C relative to those from the colder region.In a model that used region, horizon and the individual PLFA as predictors, we found that region had a subtle (0.7o), but highly significant (p

Kohl, Lukas; Laganière, Jérôme; Edwards, Kate; Lehmeier, Christoph; Min, Kyungjin; Billings, Sharon A.; Ballantyne, Ford; Van Biesen, Geert; Morrill, Penny L.; Ziegler, Susan E.

2014-05-01

340

Multiscale hydrologic impacts of dust deposition and climate warming in the Upper Colorado River Basin  

NASA Astrophysics Data System (ADS)

The Colorado River provides water to 30 million people in seven states and two countries. Climate models project runoff losses of 7-20% from the basin in this century due to human-induced climate change. Recent work has shown that decreased snow albedo from anthropogenic disturbance-induced dust loading to the CO mountains shortens the duration of snow cover by several weeks, and advances peak runoff at Lees Ferry, Arizona by an average of 3 weeks. Increases in evapotranspiration from earlier exposure of vegetation and soils decreases annual runoff by more than 1.0 billion cubic meters or ~5% of the annual average. This prior work was based on observed dust loadings during 2003-2008, however 2009 and 2010 saw unprecedented levels of dust loading on snowpacks in the Upper Colorado River basin on the order of 5 times the 2003-2008 loading. We examine the hydrologic impact of extreme dust years such as 2009/2010, and interactions with projected regional warming on the Upper Colorado River Basin and selected sub-basins.

Deems, J. S.; Painter, T.; Barsugli, J.

2012-12-01

341

Strong atmospheric chemistry feedback to climate warming from Arctic methane emissions  

USGS Publications Warehouse

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.

Isaksen, Ivar S.A.; Gauss, Michael; Myhre, Gunnar; Walter Anthony, Katey M.; Ruppel, Carolyn

2011-01-01

342

Projected climate regime shift under future global warming from multi-model, multi-scenario CMIP5 simulations  

NASA Astrophysics Data System (ADS)

This study examined shifts in climate regimes over the global land area using the Köppen-Trewartha (K-T) climate classification by analyzing observations during 1900-2010, and simulations during 1900-2100 from twenty global climate models participating in Phase 5 of the Coupled Model Inter-comparison Project (CMIP5). Under the Intergovernmental Panel on Climate Change Representative Concentration Pathways 8.5 (RCP8.5) scenario, the models projected a 3°-10 °C warming in annual temperature over the global land area by the end of the twenty-first century, with strong (moderate) warming in the high (middle) latitudes of the Northern Hemisphere and weaker warming in the tropics and the Southern Hemisphere. The projected changes in precipitation vary considerably in space and present greater uncertainties among the models. Overall, the models are consistent in projecting increasing precipitation over the high-latitude of the Northern Hemisphere, and reduced precipitation in the Mediterranean, southwestern North America, northern and southern Africa and Australia. Based on the projected changes in temperature and precipitation, the K-T climate types would shift toward warmer and drier climate types from the current climate distribution. Regions of temperate, tropical and dry climate types are projected to expand, while regions of polar, sub-polar and subtropical climate types are projected to contract. The magnitudes of the projected changes are stronger in the RCP8.5 scenario than the low emission scenario RCP4.5. On average, the climate types in 31.4% and 46.3% of the global land area are projected to change by the end of the twenty-first century under RCP4.5 and RCP8.5 scenarios, respectively. Further analysis suggests that changes in precipitation played a slightly more important role in causing shifts of climate type during the twentieth century. However, the projected changes in temperature play an increasingly important role and dominate shifts in climate type when the warming becomes more pronounced in the twenty-first century.

Feng, Song; Hu, Qi; Huang, Wei; Ho, Chang-Hoi; Li, Ruopu; Tang, Zhenghong

2014-01-01

343

Climate warming decreases the survival of the little auk (Alle alle), a high Arctic avian predator.  

PubMed

Delayed maturity, low fecundity, and high adult survival are traits typical for species with a long-life expectancy. For such species, even a small change in adult survival can strongly affect the population dynamics and viability. We examined the effects of both regional and local climatic variability on adult survival of the little auk, a long-lived and numerous Arctic seabird species. We conducted a mark-resighting study for a period of 8 years (2006-2013) simultaneously at three little auk breeding sites that are influenced by the West Spitsbergen Current, which is the main carrier of warm, Atlantic water into the Arctic. We found that the survival of adult little auks was negatively correlated with both the North Atlantic Oscillation (NAO) index and local summer sea surface temperature (SST), with a time lag of 2 and 1 year, respectively. The effects of NAO and SST were likely mediated through a change in food quality and/or availability: (1) reproduction, growth, and development of Arctic Calanus copepods, the main prey of little auks, are negatively influenced by a reduction in sea ice, reduced ice algal production, and an earlier but shorter lasting spring bloom, all of which result from an increased NAO; (2) a high sea surface temperature shortens the reproductive period of Arctic Calanus, decreasing the number of eggs produced. A synchronous variation in survival rates at the different colonies indicates that climatic forcing was similar throughout the study area. Our findings suggest that a predicted warmer climate in the Arctic will negatively affect the population dynamics of the little auk, a high Arctic avian predator. PMID:25247069

Hovinen, Johanna E H; Welcker, Jorg; Descamps, Sébastien; Strøm, Hallvard; Jerstad, Kurt; Berge, Jørgen; Steen, Harald

2014-08-01

344

Climate warming decreases the survival of the little auk (Alle alle), a high Arctic avian predator  

PubMed Central

Delayed maturity, low fecundity, and high adult survival are traits typical for species with a long-life expectancy. For such species, even a small change in adult survival can strongly affect the population dynamics and viability. We examined the effects of both regional and local climatic variability on adult survival of the little auk, a long-lived and numerous Arctic seabird species. We conducted a mark-resighting study for a period of 8 years (2006-2013) simultaneously at three little auk breeding sites that are influenced by the West Spitsbergen Current, which is the main carrier of warm, Atlantic water into the Arctic. We found that the survival of adult little auks was negatively correlated with both the North Atlantic Oscillation (NAO) index and local summer sea surface temperature (SST), with a time lag of 2 and 1 year, respectively. The effects of NAO and SST were likely mediated through a change in food quality and/or availability: (1) reproduction, growth, and development of Arctic Calanus copepods, the main prey of little auks, are negatively influenced by a reduction in sea ice, reduced ice algal production, and an earlier but shorter lasting spring bloom, all of which result from an increased NAO; (2) a high sea surface temperature shortens the reproductive period of Arctic Calanus, decreasing the number of eggs produced. A synchronous variation in survival rates at the different colonies indicates that climatic forcing was similar throughout the study area. Our findings suggest that a predicted warmer climate in the Arctic will negatively affect the population dynamics of the little auk, a high Arctic avian predator.

Hovinen, Johanna E H; Welcker, Jorg; Descamps, Sebastien; Str?m, Hallvard; Jerstad, Kurt; Berge, J?rgen; Steen, Harald

2014-01-01

345

A hydrogeologic framework for characterizing summer streamflow sensitivity to climate warming in the Pacific Northwest, USA  

NASA Astrophysics Data System (ADS)

Summer streamflows in the Pacific Northwest are largely derived from melting snow and groundwater discharge. As the climate warms, diminishing snowpack and earlier snowmelt will cause reductions in summer streamflow. Most regional-scale assessments of climate change impacts on streamflow use downscaled temperature and precipitation projections from general circulation models (GCMs) coupled with large-scale hydrologic models. Here we develop and apply an analytical hydrogeologic framework for characterizing summer streamflow sensitivity to a change in the timing and magnitude of recharge in a spatially explicit fashion. In particular, we incorporate the role of deep groundwater, which large-scale hydrologic models generally fail to capture, into streamflow sensitivity assessments. We validate our analytical streamflow sensitivities against two empirical measures of sensitivity derived using historical observations of temperature, precipitation, and streamflow from 217 watersheds. In general, empirically and analytically derived streamflow sensitivity values correspond. Although the selected watersheds cover a range of hydrologic regimes (e.g., rain-dominated, mixture of rain and snow, and snow-dominated), sensitivity validation was primarily driven by the snow-dominated watersheds, which are subjected to a wider range of change in recharge timing and magnitude as a result of increased temperature. Overall, two patterns emerge from this analysis: first, areas with high streamflow sensitivity also have higher summer streamflows as compared to low-sensitivity areas. Second, the level of sensitivity and spatial extent of highly sensitive areas diminishes over time as the summer progresses. Results of this analysis point to a robust, practical, and scalable approach that can help assess risk at the landscape scale, complement the downscaling approach, be applied to any climate scenario of interest, and provide a framework to assist land and water managers in adapting to an uncertain and potentially challenging future.

Safeeq, M.; Grant, G. E.; Lewis, S. L.; Kramer, M. G.; Staab, B.

2014-09-01

346

Short- and long-term conditioning of a temperate marine diatom community to acidification and warming  

PubMed Central

Ocean acidification and greenhouse warming will interactively influence competitive success of key phytoplankton groups such as diatoms, but how long-term responses to global change will affect community structure is unknown. We incubated a mixed natural diatom community from coastal New Zealand waters in a short-term (two-week) incubation experiment using a factorial matrix of warming and/or elevated pCO2 and measured effects on community structure. We then isolated the dominant diatoms in clonal cultures and conditioned them for 1 year under the same temperature and pCO2 conditions from which they were isolated, in order to allow for extended selection or acclimation by these abiotic environmental change factors in the absence of interspecific interactions. These conditioned isolates were then recombined into ‘artificial’ communities modelled after the original natural assemblage and allowed to compete under conditions identical to those in the short-term natural community experiment. In general, the resulting structure of both the unconditioned natural community and conditioned ‘artificial’ community experiments was similar, despite differences such as the loss of two species in the latter. pCO2 and temperature had both individual and interactive effects on community structure, but temperature was more influential, as warming significantly reduced species richness. In this case, our short-term manipulative experiment with a mixed natural assemblage spanning weeks served as a reasonable proxy to predict the effects of global change forcing on diatom community structure after the component species were conditioned in isolation over an extended timescale. Future studies will be required to assess whether or not this is also the case for other types of algal communities from other marine regimes. PMID:23980240

Tatters, Avery O.; Roleda, Michael Y.; Schnetzer, Astrid; Fu, Feixue; Hurd, Catriona L.; Boyd, Philip W.; Caron, David A.; Lie, Alle A. Y.; Hoffmann, Linn J.; Hutchins, David A.

2013-01-01

347

Influence of Climate Warming on Arctic Mammals? New Insights from Ancient DNA Studies of the collared lemming Dicrostonyx torquatus.  

NASA Astrophysics Data System (ADS)

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.

Prost, Stefan; Smirnov, Nickolay; Fedorov, Vadim B.; Sommer, Robert S.; Stiller, Mathias; Nagel, Doris; Knapp, Michael; Hofreiter, Michael

2010-05-01

348

Scientist warns against overselling climate change Climate change forecasters should admit that they cannot predict how global warming will affect  

E-print Network

that they cannot predict how global warming will affect individual countries, a leading physicist has said-of-deaths-from-ozone-predicted.html) Antarctic sea floor gives clues about effects of future global warming (/earth/environment/climatechange /5279223/Antarctic-sea-floor-gives-clues-about-affects-of-future-global-warming.html) The Vanishing Face

Stevenson, Paul

349

Understanding the causes of recent warming of mediterranean waters. How much could be attributed to climate change?  

PubMed

During the past two decades, Mediterranean waters have been warming at a rather high rate resulting in scientific and social concern. This warming trend is observed in satellite data, field data and model simulations, and affects both surface and deep waters throughout the Mediterranean basin. However, the warming rate is regionally different and seems to change with time, which has led to the question of what causes underlie the observed trends. Here, we analyze available satellite information on sea surface temperature (SST) from the last 25 years using spectral techniques and find that more than half of the warming tendency during this period is due to a non-linear, wave-like tendency. Using a state of the art hydrodynamic model, we perform a hindcast simulation and obtain the simulated SST evolution of the Mediterranean basin for the last 52 years. These SST results show a clear sinusoidal tendency that follows the Atlantic Multidecadal Oscillation (AMO) during the simulation period. Our results reveal that 58% of recent warming in Mediterranean waters could be attributed to this AMO-like oscillation, being anthropogenic-induced climate change only responsible for 42% of total trend. The observed acceleration of water warming during the 1990s therefore appears to be caused by a superimposition of anthropogenic-induced warming with the positive phase of the AMO, while the recent slowdown of this tendency is likely due to a shift in the AMO phase. It has been proposed that this change in the AMO phase will mask the effect of global warming in the forthcoming decades, and our results indicate that the same could also be applicable to the Mediterranean Sea. Henceforth, natural multidecadal temperature oscillations should be taken into account to avoid underestimation of the anthropogenic-induced warming of the Mediterranean basin in the future. PMID:24312322

Macias, Diego; Garcia-Gorriz, Elisa; Stips, Adolf

2013-01-01

350

Understanding the Causes of Recent Warming of Mediterranean Waters. How Much Could Be Attributed to Climate Change?  

PubMed Central

During the past two decades, Mediterranean waters have been warming at a rather high rate resulting in scientific and social concern. This warming trend is observed in satellite data, field data and model simulations, and affects both surface and deep waters throughout the Mediterranean basin. However, the warming rate is regionally different and seems to change with time, which has led to the question of what causes underlie the observed trends. Here, we analyze available satellite information on sea surface temperature (SST) from the last 25 years using spectral techniques and find that more than half of the warming tendency during this period is due to a non-linear, wave-like tendency. Using a state of the art hydrodynamic model, we perform a hindcast simulation and obtain the simulated SST evolution of the Mediterranean basin for the last 52 years. These SST results show a clear sinusoidal tendency that follows the Atlantic Multidecadal Oscillation (AMO) during the simulation period. Our results reveal that 58% of recent warming in Mediterranean waters could be attributed to this AMO-like oscillation, being anthropogenic-induced climate change only responsible for 42% of total trend. The observed acceleration of water warming during the 1990s therefore appears to be caused by a superimposition of anthropogenic-induced warming with the positive phase of the AMO, while the recent slowdown of this tendency is likely due to a shift in the AMO phase. It has been proposed that this change in the AMO phase will mask the effect of global warming in the forthcoming decades, and our results indicate that the same could also be applicable to the Mediterranean Sea. Henceforth, natural multidecadal temperature oscillations should be taken into account to avoid underestimation of the anthropogenic-induced warming of the Mediterranean basin in the future. PMID:24312322

Macias, Diego; Garcia-Gorriz, Elisa; Stips, Adolf

2013-01-01

351

Physiological effects of climate warming on flowering plants and insect pollinators and potential consequences for their interactions  

PubMed Central

Growing concern about the influence of climate change on flowering plants, pollinators, and the mutualistic interactions between them has led to a recent surge in research. Much of this research has addressed the consequences of warming for phenological and distributional shifts. In contrast, relatively little is known about the physiological responses of plants and insect pollinators to climate warming and, in particular, how these responses might affect plant-pollinator interactions. Here, we summarize the direct physiological effects of temperature on flowering plants and pollinating insects to highlight ways in which plant and pollinator responses could affect floral resources for pollinators, and pollination success for plants, respectively. We also consider the overall effects of these responses on plant-pollinator interaction networks. Plant responses to warming, which include altered flower, nectar, and pollen production, could modify floral resource availability and reproductive output of pollinating insects. Similarly, pollinator responses, such as altered foraging activity, body size, and life span, could affect patterns of pollen flow and pollination success of flowering plants. As a result, network structure could be altered as interactions are gained and lost, weakened and strengthened, even without the gain or loss of species or temporal overlap. Future research that addresses not only how plant and pollinator physiology are affected by warming but also how responses scale up to affect interactions and networks should allow us to better understand and predict the effects of climate change on this important ecosystem service PMID:24009624

SCAVEN, Victoria L.; RAFFERTY, Nicole E.

2013-01-01

352

A mechanism for land-ocean contrasts in global monsoon trends in a warming climate  

NASA Astrophysics Data System (ADS)

A central paradox of the global monsoon record involves reported decreases in rainfall over land during an era in which the global hydrologic cycle is both expected and observed to intensify. It is within this context that this work develops a physical basis for both interpreting the observed record and anticipating changes in the monsoons in a warming climate while bolstering the concept of the global monsoon in the context of shared feedbacks. The global-land monsoon record across multiple reanalyses is first assessed. Trends that in other studies have been taken as real are shown to likely be spurious as a result of changes in the assimilated data streams both prior to and during the satellite era. Nonetheless, based on satellite estimates, robust increases in monsoon rainfall over ocean do exist and a physical basis for this land-ocean contrast remains lacking. To address the contrast's causes, simulated trends are therefore assessed. While projections of total rainfall are inconsistent across models, the robust land-ocean contrast identified in observations is confirmed. A feedback mechanism is proposed rooted in the facts that land areas warm disproportionately relative to ocean, and onshore flow is the chief source of monsoonal moisture. Reductions in lower tropospheric relative humidity over land domains are therefore inevitable and these have direct consequences for the monsoonal convective environment including an increase in the lifting condensation level and a shift in the distribution of convection generally towards less frequent and potentially more intense events. The mechanism is interpreted as an important modulating influence on the "rich-get-richer" mechanism. Caveats for regional monsoons exist and are discussed.

Fasullo, J.

2012-09-01

353

24 CFR 3285.404 - Severe climatic conditions.  

Code of Federal Regulations, 2013 CFR

...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...

2013-04-01

354

24 CFR 3285.404 - Severe climatic conditions.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

355

24 CFR 3285.404 - Severe climatic conditions.  

Code of Federal Regulations, 2012 CFR

...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...

2012-04-01

356

24 CFR 3285.404 - Severe climatic conditions.  

Code of Federal Regulations, 2010 CFR

...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...

2010-04-01

357

Reef fish dynamic response to climatic variability in a warm eastern Mediterranean semi-enclosed basin  

NASA Astrophysics Data System (ADS)

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.

Agiadi, K.; Koskeridou, E.; Giamali, Ch.; Karakitsios, V.

2012-04-01

358

North Atlantic cyclones in CO2-induced warm climate simulations: frequency, intensity, and tracks  

Microsoft Academic Search

The effect of CO2-induced climate change on the North Atlantic storm and cyclone tracks in winter is analysed using time slice experiments\\u000a of the Hamburg atmospheric general circulation model (ECHAM3) with triangular truncation at wave number 42 (T42) and 19 levels.\\u000a The sea surface temperature (SST) and sea ice boundary conditions for these experiments are taken from a transient Intergovernmental

M. Schubert; J. Perlwitz; R. Blender; K. Fraedrich; F. Lunkeit

1998-01-01

359

Potential increase of flood hazards in Korea due to global warming from a high-resolution regional climate simulation  

NASA Astrophysics Data System (ADS)

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.

Im, Eun-Soon; Lee, Byong-Ju; Kwon, Ji-Hye; in, So-Ra; Han, Sang-Ok

2012-02-01

360

Aerosol-Induced Changes of Convective Cloud Anvils Produce Strong Climate Warming  

NASA Technical Reports Server (NTRS)

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.

Koren, I.; Remer, L. A.; Altaratz, O.; Martins, J. V.; Davidi, A.

2010-01-01

361

-Decline of arctic-alpine plants following a decade of climatic warming -679 Journal of Vegetation Science 15: 679-690, 2004  

E-print Network

Climate is among the most important influences on the pattern of species occurrences over the earth (Good in response to past climate change has been in- ferred from patterns of peripheral rarity, especially- Decline of arctic-alpine plants following a decade of climatic warming - 679 Journal

McCune, Bruce

362

Understanding Global Warming  

E-print Network

.ipcc.ch) IPCC Climate Models Thursday, January 24, 2013 #12;U.S. Climate Change Science Program (2008) Warming warming models applicable to Southern California. Findings: UCLA Center for Climate Change Solutions 2012Understanding Global Warming Math 483 Spring Semester, 2013 California State University, Northridge

Klein, David

363

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

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.

Genet, Helene [Institute of Arctic Biology (IAB), University of Alaska, Fairbanks (UAF)] [Institute of Arctic Biology (IAB), University of Alaska, Fairbanks (UAF); McGuire, A. David [University of Alaska] [University of Alaska; Barrett, K. [USGS Alaska Science Center] [USGS Alaska Science Center; Breen, Amy [International Arctic Research Center, SNAP, University of Alaska, Fairbanks (UAF)] [International Arctic Research Center, SNAP, University of Alaska, Fairbanks (UAF); Euskirchen, Eugenie S [University of Alaska] [University of Alaska; Johnstone, J. F. [University of Saskatchewan] [University of Saskatchewan; Kasischke, Eric S. [University of Maryland, College Park] [University of Maryland, College Park; Melvin, A. M. [University of Florida, Gainesville] [University of Florida, Gainesville; Bennett, A. [International Arctic Research Center, SNAP, University of Alaska, Fairbanks (UAF)] [International Arctic Research Center, SNAP, University of Alaska, Fairbanks (UAF); Mack, M. C. [University of Florida, Gainesville] [University of Florida, Gainesville; Rupp, Scott T. [International Arctic Research Center, SNAP, University of Alaska, Fairbanks (UAF)] [International Arctic Research Center, SNAP, University of Alaska, Fairbanks (UAF); Schuur, Edward [University of Florida] [University of Florida; Turetsky, M. R. [University of Guelph, Canada] [University of Guelph, Canada; Yuan, Fengming [ORNL] [ORNL

2013-01-01

364

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

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.

Genet, H; McGuire, Anthony D.; 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

365

Is the Climate of Bering Sea Warming and Affecting the Ecosystem?  

NASA Astrophysics Data System (ADS)

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.

Overland, James E.; Stabeno, Phyllis J.

2004-08-01

366

Predicting organismal vulnerability to climate warming: roles of behaviour, physiology and adaptation  

PubMed Central

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

Huey, Raymond B.; Kearney, Michael R.; Krockenberger, Andrew; Holtum, Joseph A. M.; Jess, Mellissa; Williams, Stephen E.

2012-01-01

367

Increasing contaminant burdens in an arctic fish, Burbot ( Lota lota ), in a warming climate.  

PubMed

The temporal patterns of mercury (Hg), polychlorinated biphenyls (PCBs), and other contaminants in Arctic aquatic biota are usually attributed to changing atmospheric sources. However, climate variability and change is another means of altering contaminant fate and bioavailability. We show here that the concentrations of Hg and PCBs in Mackenzie River burbot ( Lota lota ), a top predator fish and important staple food for northern Canadian communities, have increased significantly over the last 25 years despite falling or stable atmospheric concentrations, suggesting that environmental processes subsequent to atmospheric transport are responsible. Using a dated sediment core from a tributary lake near the Mackenzie River sampling site, we show that variations in Hg concentrations downcore are strongly associated with labile, algal-derived organic matter (OM). Strong temporal correlations between increasing primary productivity and biotic Hg and PCBs as reflected by burbot suggest that warming temperatures and reduced ice cover may lead to increased exposure to these contaminants in high trophic level Arctic freshwater biota. PMID:19957995

Carrie, J; Wang, F; Sanei, H; Macdonald, R W; Outridge, P M; Stern, G A

2010-01-01

368

Climate warming shifts carbon allocation from stemwood to roots in calcium-depleted spruce forests  

USGS Publications Warehouse

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.

Lapenis, Andrei Gennady; Lawrence, Gregory B.; Heim, Alexander; Zheng, Chengyang; Shortle, Walter

2013-01-01

369

Error analysis of FLC experimental data at warm/hot stamping conditions  

NASA Astrophysics Data System (ADS)

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.

Zhuang, Weimin; Zhang, Mengxi; Chen, Yanhong

2014-07-01

370

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

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.

Klein, S A; Jiang, X; Boyle, J; Malyshev, S; Xie, S

2006-07-11

371

Enviropedia: Introduction to Global Warming  

NSDL National Science Digital Library

This resource provides an overview of the concept of global warming, which is thought to be due to man-made emissions of greenhouse gases, which are largely a result of the burning of fossil fuels and deforestation. It explores the possibility that the impacts of global warming may include desertification and the destruction of other ecosystems, extreme weather conditions, and a danger to agriculture. Information on the Intergovernmental Panel on Climate Change, (IPCC), the Kyoto Protocol, the United Nations Framework Convention on Climate Change, (FCCC), and the United Kingdom Programme on Climate Change is also provided.

372

AMOC response to global warming: dependence on the background climate and response timescale  

NASA Astrophysics Data System (ADS)

This paper investigates the response of the Atlantic meridional overturning circulation (AMOC) to a sudden doubling of atmospheric CO2 in the National Center for Atmospheric Research Community Climate System Model version 3, with a focus on differences under different background climates. The findings reveal that the evolution of the AMOC differs significantly between the modern climate and the last glacial maximum (LGM). In the modern climate, the AMOC decreases (by 25 %, 4 Sv) in the first 100 years and then recovers slowly (by 6 %, 1 Sv) by the end of the 1,500-year simulation. At the LGM, the AMOC also weakens (by 8 %, 1 Sv) in the initial 90 years, but then recovers, first rapidly (by 30 %, 4 Sv) over the following 300 years, and then slowly (by 13 %, 1.6 Sv) during the remainder of the integration. These results suggest that the responses of the AMOC under both climates have a similar initial rapid weakening period of ~100 years and a final slow strengthening period over 1,000 years long. However, additional intermediate period of ~300 years does occur for the LGM, with rapid intensification in the AMOC. Analyses suggest that the rapid intensification is triggered and sustained primarily by a coupled sea ice-ocean feedback: the reduction of meltwater flux in the northern North Atlantic—associated with the remarkable sea-ice retreat at the LGM—intensifies the AMOC and northward heat transport, which, in turn, causes further sea-ice retreat and more reduction of meltwater. These processes are insignificant under modern conditions.

Zhu, Jiang; Liu, Zhengyu; Zhang, Jiaxu; Liu, Wei

2014-05-01

373

Genotypic trait variation modifies effects of climate warming and nitrogen deposition on litter mass loss and microbial respiration.  

PubMed

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

Hines, Jes; Reyes, Marta; Mozder, Thomas J; Gessner, Mark O

2014-12-01

374

Nematode community shifts in response to experimental warming and canopy conditions are associated with plant community changes in the temperate-boreal forest ecotone.  

PubMed

Global climate warming is one of the key forces driving plant community shifts, such as range shifts of temperate species into boreal forests. As plant community shifts are slow to observe, ecotones, boundaries between two ecosystems, are target areas for providing early evidence of ecological responses to warming. The role of soil fauna is poorly explored in ecotones, although their positive and negative effects on plant species can influence plant community structure. We studied nematode communities in response to experimental warming (ambient, +1.7, +3.4 °C) in soils of closed and open canopy forest in the temperate-boreal ecotone of Minnesota, USA and calculated various established nematode indices. We estimated species-specific coverage of understory herbaceous and shrub plant species from the same experimental plots and tested if changes in the nematode community are associated with plant cover and composition. Individual nematode trophic groups did not differ among warming treatments, but the ratio between microbial-feeding and plant-feeding nematodes increased significantly and consistently with warming in both closed and open canopy areas and at both experimental field sites. The increase in this ratio was positively correlated with total cover of understory plant species, perhaps due to increased predation pressure on soil microorganisms causing higher nutrient availability for plants. Multivariate analyses revealed that temperature treatment, canopy conditions and nematode density consistently shaped understory plant communities across experimental sites. Our findings suggest that warming-induced changes in nematode community structure are associated with shifts in plant community composition and productivity in the temperate-boreal forest ecotones. PMID:24668014

Thakur, Madhav Prakash; Reich, Peter B; Fisichelli, Nicholas A; Stefanski, Artur; Cesarz, Simone; Dobies, Tomasz; Rich, Roy L; Hobbie, Sarah E; Eisenhauer, Nico

2014-06-01

375

Warm Humid Climate: Methodology to Study Air Temperature Distribution: Mobile Phones Base Stations as Viable Alternative for Fixed Points  

E-print Network

Engineering, Architecture and Urban Planning – UNICAMP, Campinas, Brazil e-mail: angelina@fec.unicamp.br; e-mail: lucila@fec.unicamp.br (3) Federal University of Rio Grande do Norte - Department of Architecture and Urban Planning Caixa Postal 6021 Cep... 13083 970 Campinas/ SP – Brazil - Tel. 55 19 37882384 ABSTRACT This paper presents partial results of a research about urban space in a warm-humid climate at the Northeast region of Brazil. The objective is to verify the air temperature...

Araujo, V.; Costa, A.; Labaki, L.

2006-01-01

376

Light and Heavy Fractions of Soil Organic Matter in Response to Climate Warming and Increased Precipitation in a Temperate Steppe  

PubMed Central

Soil is one of the most important carbon (C) and nitrogen (N) pools and plays a crucial role in ecosystem C and N cycling. Climate change profoundly affects soil C and N storage via changing C and N inputs and outputs. However, the influences of climate warming and changing precipitation regime on labile and recalcitrant fractions of soil organic C and N remain unclear. Here, we investigated soil labile and recalcitrant C and N under 6 years' treatments of experimental warming and increased precipitation in a temperate steppe in Northern China. We measured soil light fraction C (LFC) and N (LFN), microbial biomass C (MBC) and N (MBN), dissolved organic C (DOC) and heavy fraction C (HFC) and N (HFN). The results showed that increased precipitation significantly stimulated soil LFC and LFN by 16.1% and 18.5%, respectively, and increased LFC?HFC ratio and LFN?HFN ratio, suggesting that increased precipitation transferred more soil organic carbon into the quick-decayed carbon pool. Experimental warming reduced soil labile C (LFC, MBC, and DOC). In contrast, soil heavy fraction C and N, and total C and N were not significantly impacted by increased precipitation or warming. Soil labile C significantly correlated with gross ecosystem productivity, ecosystem respiration and soil respiration, but not with soil moisture and temperature, suggesting that biotic processes rather than abiotic factors determine variations in soil labile C. Our results indicate that certain soil carbon fraction is sensitive to climate change in the temperate steppe, which may in turn impact ecosystem carbon fluxes in response and feedback to climate change. PMID:22479373

Song, Bing; Niu, Shuli; Zhang, Zhe; Yang, Haijun; Li, Linghao; Wan, Shiqiang

2012-01-01

377

Effects of 20th century warming and climate variability on flood risk in the western U.S  

Microsoft Academic Search

Using precipitation and temperature data for the 20th century in combination with a macroscale hydrologic model, we evaluate changes in flood risk in the western U.S. associated both with century-scale warming and interannual climate variations. In addition, we examine the implications of apparent increases in precipitation variability over the region since the mid-1970s. We use detrended temperature data representing early

Alan F. Hamlet; Dennis P. Lettenmaier

2007-01-01

378

Carbon Inputs to Arctic Streams and Lakes during Climate Warming: Lessons from Prehistory  

NASA Astrophysics Data System (ADS)

Warming of the Arctic will cause perennially frozen ground (permafrost) to thaw and release ancient carbon into streams and lakes. How sensitive is permafrost-carbon release to warming? One way to answer this question is to quantify how permafrost C responded to prehistoric warming events. Here we use lake sediments as a long-term record of permafrost-C release from an arctic watershed. The radiocarbon-age offset is the age difference between the true age of deposition (the 14C age of delicate, terrestrial plant remains) and the apparent age of the sedimentary stratum where these plant remains were laid down (the 14C age of the surrounding bulk sediment). In many arctic lakes, true age is younger than apparent age because bulk organic sediment contains particulate and dissolved C originating from soils, peat, and permafrost. Shifts in the magnitude of the 14C-age offset over time provide a proxy for changes in the relative amount of permafrost C released from the watershed. Our age-offset record comes from the Lake of the Pleistocene (LOP), a partially-drained lake basin on the northern flank of the Brooks Range whose macrofossil-rich deposits were laid down continuously after 14,500 calendar years BP (cal yr BP). The LOP watershed is underlain by continuous permafrost and contains extensive, frozen peatlands. We excavated a wide swath of the former lake bed and collected paired samples of twigs and their enclosing sediment to construct a high-resolution age-offset chronology. Today, the radiocarbon age of dissolved and particulate organic matter being deposited in the LOP basin is 2,500 yr. During the warmer-than-present, Bølling-Allerød period (14,700-12,800 cal yr BP), and during Holocene Thermal Maximum (11,700-8500 cal yr BP), the age offset doubled to around 4,000 yr. This enhanced input of old C was interrupted during a reversion to cold conditions during the Younger Dryas (12,800-11,700 cal yr BP). Interesting, 14C-age offsets during the YD were similar to today's, suggesting that the thick peat now covering much of the LOP watershed is stabilizing permafrost C in the face of ongoing warming; however, the shielding capacity of the modern peat cover may now be approaching its limit. Enhanced permafrost thaw during the Bølling-Allerød and during the Holocene Thermal Maximum occurred despite the presence of widespread peat cover at those times, and dates on extralimital plant species suggest summer temperatures during these prehistoric warm periods were only 1-3 degrees C warmer than today. We may now be approaching a threshold leading to greatly enhanced permafrost-C release from this watershed.

Mann, D. H.; Gaglioti, B.; Pohlmann, J. W.; Rasic, J. T.; Jones, B. M.; Wooller, M. J.

2013-12-01

379

A cost analysis of photovoltaic technologies under Jamaica'S climatic conditions  

Microsoft Academic Search

With the spiraling cost of imported fossil fuels and high values of insolation, the Caribbean region hopes that photovoltaic (PV) technologies will provide a more cost effective and secure energy solution. PV performance parameters are given under Standard Test Conditions (STC). Since STC is never realised under normal operational conditions (NOC) within Jamaica's climate, it is essential that we investigate

Darlene A. Field; Claude McNamarah

2010-01-01

380

Climate warming increases biodiversity of small rodents by favoring rare or less abundant species in a grassland ecosystem.  

PubMed

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

Jiang, Guangshun; Liu, Jun; Xu, Lei; Yu, Guirui; He, Honglin; Zhang, Zhibin

2013-06-01

381

Impact of the Atlantic Warm Pool on Climate and Hurricanes: An Overview of Recent Understanding  

NASA Astrophysics Data System (ADS)

The Atlantic Warm Pool (AWP) with a large body of warm water is comprised of the Intra-Americas Sea (i.e., the Gulf of Mexico and the Caribbean Sea) and the western tropical North Atlantic. Located to its northeastern side is the North Atlantic Subtropical High (NASH) that produces the tropical easterly trade winds. The easterly trade winds carry moisture from the tropical North Atlantic into the Caribbean Sea where the flow intensifies forming the Caribbean Low-Level Jet (CLLJ). The CLLJ then splits into two branches: One turning northward and connecting with the Great Plains Low-Level Jet (GPLLJ), and the other one continuing westward across Central America into the eastern North Pacific. The easterly CLLJ and its moisture transport are maximized in the summer and winter, whereas they are minimized in the fall and spring. This semi-annual feature results from the semi-annual variation of sea level pressure in the Caribbean region owing to the westward extension and eastward retreat of the NASH. The summertime strong easterly CLLJ is associated with a maximum of sea level pressure, a relative minimum of rainfall (the mid-summer drought), and a minimum of tropical cyclogenesis in July in the Caribbean Sea. The NCAR community atmospheric model ensemble runs show that climate response to the AWP heating extends beyond the AWP region to the eastern North Pacific and North America, owing to the westward propagation of Rossby wave response. The effect of the AWP is to weaken the summertime NASH, especially at its southwestern edge. The AWP also strengthens the summertime continental low over the North American monsoon region. In response to these pressure changes, the easterly CLLJ and its moisture transport are weakened, but its semi-annual feature does not change. The AWP-induced change of atmospheric circulation changes the moisture convergence that results in increased rainfall in the AWP region and the eastern North Pacific. The model runs also show that the effect of the AWP is to weaken the southerly GPLLJ and its northward moisture transport and thus to decrease rainfall in the United States east of the Rocky Mountains. Finally, the AWP largely reduces the tropospheric vertical wind shear in the main development region that favors hurricane formation and development during August-October.

Wang, C.; Lee, S.; Enfield, D.

2007-05-01

382

Impact of the Atlantic Warm Pool on the Summer Climate of the Western Hemisphere  

NASA Astrophysics Data System (ADS)

The North Atlantic subtropical high (NASH), being the strongest during the summer, determines the strength of the tropical easterly trade winds at its southern flank. The easterly trade winds carry moisture from the tropical North Atlantic into the Caribbean Sea where the flow intensifies forming the Caribbean low-level jet (CLLJ). The CLLJ then splits into two branches: one turning northward and connecting with the Great Plains low-level jet (GPLLJ), and the other one continuing westward across Central America into the eastern North Pacific. This paper finds that the easterly CLLJ is maximized in the summer and winter, whereas it is minimized in the fall and spring. The semi-annual feature of the CLLJ results from the semi-annual variation of sea level pressure in the Caribbean region owing to the westward extension and eastward retreat of the NASH. The Atlantic warm pool (AWP) with a large body of warm water is comprised of the Gulf of Mexico, the Caribbean Sea, and the western tropical North Atlantic. The NCAR community atmospheric model and observational data are used to investigate the impact of the AWP on the summer climate of the Western Hemisphere. Two groups of the model ensemble runs with and without the AWP are performed and compared. The model results show that the AWP is to weaken the summertime NASH, especially at its southwestern edge. The AWP also strengthens the summertime continental low over the North American monsoon region. In response to these pressure changes, the strength of the CLLJ is weakened, but its semi-annual feature does not change. The weakening of the CLLJ decreases the westward moisture transport from the AWP and thus suppresses rainfall in the eastern North Pacific. Our model runs show that the effect of the AWP is to weaken the southerly wind of the GPLLJ. However, the AWP strengthens the northward moisture transport of the GPLLJ in the summer because the AWP-induced increase of specific humidity overcomes the weakening of southerly wind, and vice versa in the fall. Finally, the AWP largely reduces the tropospheric vertical wind shear in the main development region that favors hurricane formation and development during August-October.

Wang, C.; Lee, S.; Enfield, D.

2006-12-01

383

Climatic impacts of fresh water hosing under Last Glacial Maximum conditions: a multi-model study  

NASA Astrophysics Data System (ADS)

Fresh water hosing simulations, in which a fresh water flux is imposed in the North Atlantic to force fluctuations of the Atlantic Meridional Overturning Circulation, have been routinely performed, first to study the climatic signature of different states of this circulation, then, under present or future conditions, to investigate the potential impact of a partial melting of the Greenland ice sheet. The most compelling examples of climatic changes potentially related to AMOC abrupt variations, however, are found in high resolution palaeo-records from around the globe for the last glacial period. To study those more specifically, more and more fresh water hosing experiments have been performed under glacial conditions in the recent years. Here we compare an ensemble constituted by 11 such simulations run with 6 different climate models. All simulations follow a slightly different design, but are sufficiently close in their design to be compared. They all study the impact of a fresh water hosing imposed in the extra-tropical North Atlantic. Common features in the model responses to hosing are the cooling over the North Atlantic, extending along the sub-tropical gyre in the tropical North Atlantic, the southward shift of the Atlantic ITCZ and the weakening of the African and Indian monsoons. On the other hand, the expression of the bipolar see-saw, i.e., warming in the Southern Hemisphere, differs from model to model, with some restricting it to the South Atlantic and specific regions of the southern ocean while othe