Sample records for warm climatic conditions

  1. Why were Past North Atlantic Warming Conditions Associated with Drier Climate in the Western United States?

    NASA Astrophysics Data System (ADS)

    Wong, C. I.; Potter, G. L.; Montanez, I. P.; Otto-Bliesner, B. L.; Behling, P.; Oster, J. L.

    2014-12-01

    Investigating climate dynamics governing rainfall over the western US during past warmings and coolings of the last glacial and deglaciation is pertinent to understanding how precipitation patterns might change with future global warming, especially as the processes driving the global hydrological reorganization affecting this drought-prone region during these rapid temperature changes remain unresolved. We present model climates of the Bølling warm event (14,500 years ago) and Younger Dryas cool event (12,200 years ago) that i) uniquely enable the assessment of dueling hypothesis about the atmospheric teleconnections responsible for abrupt temperature shifts in the North Atlantic region to variations in moisture conditions across the western US, and ii) show that existing hypotheses about these teleconnections are unsupported. Modeling results show no evidence for a north-south shift of the Pacific winter storm track, and we argue that a tropical moisture source with evolving trajectory cannot explain alternation between wet/dry conditions, which have been reconstructed from the proxy record. Alternatively, model results support a new hypothesis that variations in the intensity of the winter storm track, corresponding to its expansion/contraction, can account for regional moisture differences between warm and cool intervals of the last deglaciation. Furthermore, we demonstrate that the mechanism forcing the teleconnection between the North Atlantic and western US is the same across different boundary conditions. In our simulation, during the last deglaciation, and in simulations of future warming, perturbation of the Rossby wave structure reconfigures the atmospheric state. This reconfiguration affects the Aleutian Low and high-pressure ridge over and off of the northern North American coastline driving variability in the storm track. Similarity between the processes governing the climate response during these distinct time intervals illustrates the robust nature of the teleconnection, a novel result that provides context for understanding the climate processes governing the response of moisture variability to future climate change.

  2. Trends of Teleconnection indices that affect Mediterranean climate under warming conditions

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Nazarenko, Larissa; Tausnev, Nickolai; Hansen, James

    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.

  4. Warm climate surprises

    SciTech Connect

    Overpeck, J.T. [National Geophysical Data Center, Boulder, CO (United States)

    1996-03-29

    Over the last decade, paleoclimatic data from ice cores and sediments have shown that the climate system is capable of switching between significantly different modes, suggesting that climatic surprises may lie ahead. Most attention in the growing area of abrupt climatic change research continues to be focused on large changes observed during glacial periods. The weight of paleoclimatic evidence now suggests that conforting conclusions of benign warm climate variability may be incorrect. The article goes on to discuss the evidence for this. 17 refs.

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

    Microsoft Academic Search

    Larissa Nazarenko; Nickolai Tausnev; James Hansen

    2006-01-01

    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

  6. Even warm climates get the shivers

    SciTech Connect

    Kerr, R.A.

    1993-07-16

    Researchers in the Greenland Ice-Core Project (GRIP) have found evidence of sharp climate shifts during the last two intergalcials. The Greenland ice sheet evidence shows that Greenland, over and over for decades to thousands of years, cooled drastically from temperatures equal to or higher than today's, often to virtual ice age conditions. The researchers believe that disruptions in the flow of warm water from the southern Atlantic to the North Atlantic, and the return flow of cold water to the south, may be linked to these climatic fluctuations. The present climate appears relatively stable, but that may change if temperatures warm due to increases in atmospheric greenhouse gases.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  8. Plant growth and fitness of Scabiosa columbaria under climate warming conditions

    Microsoft Academic Search

    Andrea R. Pluess; Esther Frei; Chris J. Kettle; Thomas Hahn; Jaboury Ghazoul

    2011-01-01

    Background: Plants occupying wide altitudinal gradients may be adapted to their altitude of origin. Upward expansion of lowland populations in response to climate change might therefore facilitate species persistence at higher elevations by introducing pre-adapted genes.Aim: We compared plant growth and fitness in Scabiosa columbaria originating from low and high elevations (ca. 600 m and ca. 1200 m above sea level (a.s.l.))

  9. Plant growth and fitness of Scabiosa columbaria under climate warming conditions

    Microsoft Academic Search

    Andrea R. Pluess; Esther Frei; Chris J. Kettle; Thomas Hahn; Jaboury Ghazoul

    2012-01-01

    Background: Plants occupying wide altitudinal gradients may be adapted to their altitude of origin. Upward expansion of lowland populations in response to climate change might therefore facilitate species persistence at higher elevations by introducing pre-adapted genes.Aim: We compared plant growth and fitness in Scabiosa columbaria originating from low and high elevations (ca. 600 m and ca. 1200 m above sea level (a.s.l.))

  10. Warming asymmetry in climate change simulations

    Microsoft Academic Search

    G. M. Flato; G. J. Boer

    2001-01-01

    Climate change simulations made with coupled global climate models typically show a marked hemispheric asymmetry with more warming in the northern high lati- tudes than in the south. This asymmetry is ascribed to heat uptake by the ocean at high southern latitudes. A re- cent version of the CCCma climate model exhibits a much more symmetric warming, compared to an

  11. Soil degradation, global warming and climate impacts

    E-print Network

    Feddema, Johannes J.; Freire, Sergio Carneiro

    2001-01-01

    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...

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

    E-print Network

    Haller, Gary L.

    WHAT'S IN A NAME? GLOBAL WARMING VERSUS CLIMATE CHANGE May 2014 #12;What's In A Name? Global Warming vs. Climate Change 1 TABLE OF CONTENTS PREFACE NATIONAL SURVEY STUDY 2: GLOBAL WARMING VS. CLIMATE CHANGE............................ 10 Is global

  13. Precipitation efficiency of the Colorado mountains under warmed climate

    NASA Astrophysics Data System (ADS)

    Nogherotto, R.; Grubiši?, V.; Rasmussen, Rm

    2010-09-01

    The analysis to date of high-resolution simulations of seasonal snowfall over Colorado Headwaters region under the current and future warmed climate conditions show the increase of precipitation on the order of 25% over a large model domain covering a large portion of the western US and about 10% in the high-elevation parts of the Colorado Headwaters region (Rassmussen et al. 2010). Both of these numbers are higher than 4-7% increase predicted by global models over the same region. In this study we examine the efficiency of mountains in the Colorado Headwaters region in producing the orographic precipitation and how that efficiency changes under the warmed climate conditions. The important elements in the pathway to orographic precipitation are: i) the availability and spatial distribution of water vapor, and ii) the dynamic forcing including the large-scale flow as well as its orographic modification. The precipitation efficiency is examined through water vapor flux, which, as an integral quantity, reflects the effect of both the water vapor mixing ratio as well as the horizontal wind. The analysis is based on high-resolution climate-runoff simulations for the Colorado Headwaters region for the current and future warmed climate for four water years, one dry (2001/2002), two average (2003/2004 and 2005/2006) and one wet year (2007/2008), exploiting the Pseudo-Global-Warming (PGW) approach for the future climate simulations.

  14. Climate change: Patterns of tropical warming

    NASA Astrophysics Data System (ADS)

    Clement, Amy C.; Baker, Andrew C.; Leloup, Julie

    2010-01-01

    The effect of rising greenhouse-gas emissions on climate is not uniform across the globe. An analysis of the mechanisms behind model-projected changes in ocean temperature gives greater confidence in the pattern of tropical warming and its potential impacts.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    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

  16. Trophic amplification of climate warming

    PubMed Central

    Kirby, Richard R.; Beaugrand, Gregory

    2009-01-01

    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

  17. Climate warming will not decrease winter mortality

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  19. Response of ocean ecosystems to climate warming

    NASA Astrophysics Data System (ADS)

    Sarmiento, J. L.; Slater, R.; Barber, R.; Bopp, L.; Doney, S. C.; Hirst, A. C.; Kleypas, J.; Matear, R.; Mikolajewicz, U.; Monfray, P.; Soldatov, V.; Spall, S. A.; Stouffer, R.

    2004-09-01

    We examine six different coupled climate model simulations to determine the ocean biological response to climate warming between the beginning of the industrial revolution and 2050. We use vertical velocity, maximum winter mixed layer depth, and sea ice cover to define six biomes. Climate warming leads to a contraction of the highly productive marginal sea ice biome by 42% in the Northern Hemisphere and 17% in the Southern Hemisphere, and leads to an expansion of the low productivity permanently stratified subtropical gyre biome by 4.0% in the Northern Hemisphere and 9.4% in the Southern Hemisphere. In between these, the subpolar gyre biome expands by 16% in the Northern Hemisphere and 7% in the Southern Hemisphere, and the seasonally stratified subtropical gyre contracts by 11% in both hemispheres. The low-latitude (mostly coastal) upwelling biome area changes only modestly. Vertical stratification increases, which would be expected to decrease nutrient supply everywhere, but increase the growing season length in high latitudes. We use satellite ocean color and climatological observations to develop an empirical model for predicting chlorophyll from the physical properties of the global warming simulations. Four features stand out in the response to global warming: (1) a drop in chlorophyll in the North Pacific due primarily to retreat of the marginal sea ice biome, (2) a tendency toward an increase in chlorophyll in the North Atlantic due to a complex combination of factors, (3) an increase in chlorophyll in the Southern Ocean due primarily to the retreat of and changes at the northern boundary of the marginal sea ice zone, and (4) a tendency toward a decrease in chlorophyll adjacent to the Antarctic continent due primarily to freshening within the marginal sea ice zone. We use three different primary production algorithms to estimate the response of primary production to climate warming based on our estimated chlorophyll concentrations. The three algorithms give a global increase in primary production of 0.7% at the low end to 8.1% at the high end, with very large regional differences. The main cause of both the response to warming and the variation between algorithms is the temperature sensitivity of the primary production algorithms. We also show results for the period between the industrial revolution and 2050 and 2090.

  20. Climate Warming Threatens Semi-arid Forests in Inner Asia

    NASA Astrophysics Data System (ADS)

    WU, X.; Liu, H.; Qi, Z.; Li, X.

    2014-12-01

    A line of evidences reveal an increasing tree growth decline and tree mortality mainly attributable to climate warming and the warming-mediated changes in drought and other processes (such as fire and insect dynamics) in many parts of world tropical, temperate and boreal forests. However, the growth responses to climate change of the widely distributed semi-arid forests are unclear. Here, we synthetically investigate the tree growth patterns during past decades and its interannual response to climate variations in Inner Asia combining the ground truth field survey and samplings, remote sensing observations and climate data. We identified a pervasive tree growth decline since mid-1990s in semi-arid forests in Inner Asia. The widely observed tree growth decline is dominantly attributable to warming-induced water stress during pre- and early growing season. Tree growth of semi-arid forests in Inner Asia is particularly susceptible to spring warming and has been suffering a prolonged growth limitation in recent decades due to spring warming-mediated water conditions. Additionally, we identified a much slower growth rate in younger trees and a lack of tree regeneration in these semi-arid forests. The widely observed forest growth reduction and lack of tree regeneration over semi-arid forests in Inner Asia could predictably exert great effects on forest structure, regionally/globally biophysical and biochemical processes and the feedbacks between biosphere and atmosphere. Notably, further increases in forest stress and tree mortality could be reasonably expected, especially in context of the increase frequency and severity of high temperature and heat waves and changes in forest disturbances, potentially driving the eventual regional loss of current semi-arid forests. Given the potential risks of climate induced forest dieback, increased management attention to adaptation options for enhancing forest resistance and resilience to projected climate stress can be expected. However, the functionally realistic mechanisms beneath the pervasively climate-induced forest decline/dieback still remain unclear. Network-based long-term surveys and experiment studies are urgently needed for further understandings regarding the responses of forest/tree growth to climate warming/variations.

  1. Effects of Arctic warming on Eurasian climate

    NASA Astrophysics Data System (ADS)

    Uotila, Petteri; Vihma, Timo

    2015-04-01

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

  2. Divergence of reproductive phenology under climate warming

    PubMed Central

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

    2007-01-01

    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

  3. Lagging adaptation to warming climate in Arabidopsis thaliana.

    PubMed

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

    2014-06-01

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

  4. Climatic warming disrupts recurrent Alpine insect outbreaks

    PubMed Central

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

    2010-01-01

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

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

    E-print Network

    Minnesota, University of

    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

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

    NASA Astrophysics Data System (ADS)

    Käyhkö, Jukka

    2014-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1987-08-01

    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.

  8. Multiple vegetation states in a warm climate

    NASA Astrophysics Data System (ADS)

    Port, Ulrike; Claussen, Martin

    2014-05-01

    Using the Max Planck earth system model, multiple steady states in vegetation cover are evaluated for preindustrial and Early Eocene boundary conditions. By setting the soil albedo either to a value similar to vegetation albedo or to a value much higher than vegetation albedo, the hydrological and the albedo effect of vegetation on climate are separated. Considering only the hydrological effect, multiple solutions for the Early Eocene vegetation cover exist. In central Asia, a desert evolves. This desert is smaller when the simulation is started with trees on all continents instead of bare soil. Started with trees, the climate in central Asia is more humid than when started with bare soil. In the more humid climate, more vegetation grows. For the preindustrial climate, only one solution for vegetation exists. The atmospheric circulation prevents multiple solutions for vegetation in the Sahara. Strong subsidence prevails over the Sahara. Under strong subsidence the hydrological effect becomes ineffective. Considering the hydrological and the albedo effect of vegetation, only one solution for Early Eocene and preindustrial vegetation exists. Starting the simulations with trees, the Early Eocene central Asia and preindustrial Sahara start from a humid climate, but the initial climate is not humid enough to allow a dense vegetation cover. With shrinking vegetation cover, surface albedo increases. Increasing albedo amplifies aridification by inducing the Charney effect. The vegetation cover shrinks further until a dry desert state is reached. This study shows that the existence of multiple steady vegetation states depends on the boundary conditions, such as continent distribution. This result implies that the existence and the driving mechanisms of multiple stable vegetation states differ for present day, past, and probably future conditions.

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

    E-print Network

    Keller, Arturo A.

    Climate Warming and Adaptability of High-Elevation Hydropower Generation in California Kaveh Madani's high-elevation hydropower system is composed of more than 150 power plants. Most of the associated to winter, the adaptability of high-elevation hydropower system to new climatic conditions is in question

  10. Experience with veterinary vaccines in warm climates.

    PubMed

    Tulasne, J J; Lefèvre, P C; Blancou, J

    1996-01-01

    After a short description of the African laboratories manufacturing veterinary vaccines, the authors explain the main constraints for the use, in the field, of veterinary vaccines in warm climates. The need to respect the cold chain from the supplier of vaccines to the recipient animal is emphasised. In the Ivory Coast, during national vaccination campaigns, it has been proved that the quality of the rinderpest and contagious bovine pleuropneumonia vaccines is satisfactory when there is no disruption in the cold transport services. The data of this survey are exposed. In the framework of a project entitled "Thermostable rinderpest Vaccine, Transfer of Technology", a thermostable vaccine has been developed. It is manufactured in different African laboratories and integrated in some Pan African Rinderpest Campaign (PARC) vaccination programmes. On the other hand, the prospects offered by new thermotolerant attenuated vaccines against Newcastle disease are exposed. Finally, the authors present an outlook on the development of thermoresistant veterinary vaccines, such as those produced by genetic engineering, in particular with pox virus vectors. PMID:8854000

  11. Why tropical forest lizards are vulnerable to climate warming

    PubMed Central

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

    2009-01-01

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

  12. Climate heterogeneity modulates impact of warming on tropical insects.

    PubMed

    Bonebrake, Timothy C; Deutsch, Curtis A

    2012-03-01

    Evolutionary history and physiology mediate species responses to climate change. Tropical species that do not naturally experience high temperature variability have a narrow thermal tolerance compared to similar taxa at temperate latitudes and could therefore be most vulnerable to warming. However, the thermal adaptation of a species may also be influenced by spatial temperature variations over its geographical range. Spatial climate gradients, especially from topography, may also broaden thermal tolerance and therefore act to buffer warming impacts. Here we show that for low-seasonality environments, high spatial heterogeneity in temperature correlates significantly with greater warming tolerance in insects globally. Based on this relationship, we find that climate change projections of direct physiological impacts on insect fitness highlight the vulnerability of tropical lowland areas to future warming. Thus, in addition to seasonality, spatial heterogeneity may play a critical role in thermal adaptation and climate change impacts particularly in the tropics. PMID:22624199

  13. The Climate Policy Narrative for a Dangerously Warming World

    SciTech Connect

    Sanford, Todd [Union of Concerned Scientists] [Union of Concerned Scientists; Frumhoff, Peter [Union of Concerned Scientists] [Union of Concerned Scientists; Luers, Amy [Skoll Global Threats Fund] [Skoll Global Threats Fund; Gulledge, Jay [ORNL] [ORNL

    2014-01-01

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

  14. Warming and Dimming: An Econometric Assessment of Climate Change

    Microsoft Academic Search

    Victoria Prowse; James Reade; Simon Quinn; Melissa Dell; Tom Holden; Thomas Flury

    Global warming is a serious concern for policy in the present context. In this research, we explore the different effects of carbon dioxide and aerosols upon that process. Carbon dioxide is known to have a deleterious effect upon climate. Before now, political action taken to fi ght global warming has aimed mainly at reducing the emission of carbon dioxide. Nobel

  15. Climate Warming and Water Management Adaptation for California

    Microsoft Academic Search

    Stacy K. Tanaka; Tingju Zhu; Jay R. Lund; Richard E. Howitt; Marion W. Jenkins; Manuel A. Pulido; Mélanie Tauber; Randall S. Ritzema; Inês C. Ferreira

    2006-01-01

    The ability of California's water supply system to adapt to long-term climatic and demographic changes is examined. Two climate warming and a historical climate scenario are examined with population and land use estimates for the year 2100 using a statewide economic-engineering optimization model of water supply management. Methodologically, the results of this analysis indicate that for long-term climate change studies

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

    SciTech Connect

    Knutson, T.R.; Tuleya, R.E.; Kurihara, Y. [National Oceanic and Atmospheric Administration, Princeton, NJ (United States)] [National Oceanic and Atmospheric Administration, Princeton, NJ (United States)

    1998-02-13

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

  17. Climatic warming in North America: Analysis of borehole temperatures

    SciTech Connect

    Deming, D. [Univ. of Oklahoma, Norman, OK (United States)

    1995-06-16

    The primary database used to assess climatic warming over the last 100 to 150 years is the history of surface air temperatures (SATs) as recorded on a daily basis for weather forecasting. Climatic information missing from the truncated SAT record may be found in borehole temperature profiles. Changes in ground surface temperature (GST) propagate into the subsurface, exponentially decreasing in amplitude with increasing time and depth. Studies to date have shown that changes in SAT tend to be tracted in GST changes and GST is a valid indicator of climate change. Studies of borehole temperatures provide a relatively good constraint on the total magnitude of warming; inferences concerning the date at which the warming trend began and the rate at which it proceeded are much less certain. The available evidence from both GST and SAT studies is sonsistant with a major climatic warming over the North American Continent that likely began near the middle of the 19th century in the east, later in the west. The magnitude of warming in the east estimated from changes in GST significantly exceeds that estimated from SAT. A cause and effect relationship between anthropogenic activities and climatic warming cannot be demonstrated unambiguously at the present time. 29 refs., 2 figs.

  18. Impact of global warming and climate change on social development

    Microsoft Academic Search

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

    2010-01-01

    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

  19. Global warming and Arctic climate. Raymond S. Bradley

    E-print Network

    Mountziaris, T. J.

    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

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

    NASA Astrophysics Data System (ADS)

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

    2008-04-01

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

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

    E-print Network

    Restrepo, Juan M.

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

  2. ENSO nonlinearity in a warming climate

    Microsoft Academic Search

    J. BoucharelB; B. Dewitte; Y. du Penhoat; B. Garel; S.-W. Yeh; J.-S. Kug

    The El Niño Southern Oscillation (ENSO) is known as the strongest natural inter-annual climate signal, having widespread consequences\\u000a on the global weather, climate, ecology and even on societies. Understanding ENSO variations in a changing climate is therefore\\u000a of primordial interest to both the climate community and policy makers. In this study, we focus on the change in ENSO nonlinearity\\u000a due

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

    PubMed Central

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

    2010-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  5. Climatic warming disrupts recurrent Alpine insect outbreaks

    E-print Network

    Liebhold, Andrew

    in LBM outbreak pattern highlights how interacting species with differential response rates to climate change can result in dramatic ecological changes. traveling wave | tree rings | tri-trophic | Lepidoptera

  6. Hudson Bay Ringed Seal: Ecology in a Warming Climate

    Microsoft Academic Search

    M. Chambellant

    \\u000a Ringed seals (Phoca hispida) have evolved to exploit snow covered sea-ice platforms for reproduction and survival and may face critical challenges with\\u000a ongoing and predicted climate change. The Hudson Bay ecosystem is already showing signs of climate warming raising concerns\\u000a for the ecological, economical, and culturally-significant ringed seals of Hudson Bay. This chapter summarizes the current\\u000a knowledge on ringed seals

  7. Climate and conflicts: the security risks of global warming

    Microsoft Academic Search

    Jürgen Scheffran; Antonella Battaglini

    2011-01-01

    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

  8. Climate Warming and Disease Risks for Terrestrial and Marine Biota

    NASA Astrophysics Data System (ADS)

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

    2002-06-01

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

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

    USGS Publications Warehouse

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

    2002-01-01

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

  10. Climate Science in a Nutshell: Evidence of a Warming Planet

    NSDL National Science Digital Library

    Planet Nutshell

    This video is part of the Climate Science in a Nutshell series. This short, animated video looks at evidence of a rapidly warming planet. It discusses how air bubbles in ice cores can be used to estimate Earth's average air temperature for thousands of years and how direct measurements document air temperatures from 1880.

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

    ERIC Educational Resources Information Center

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

    2009-01-01

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

  12. Non-climatic thermal adaptation: implications for species' responses to climate warming.

    PubMed

    Marshall, David J; McQuaid, Christopher D; Williams, Gray A

    2010-10-23

    There is considerable interest in understanding how ectothermic animals may physiologically and behaviourally buffer the effects of climate warming. Much less consideration is being given to how organisms might adapt to non-climatic heat sources in ways that could confound predictions for responses of species and communities to climate warming. Although adaptation to non-climatic heat sources (solar and geothermal) seems likely in some marine species, climate warming predictions for marine ectotherms are largely based on adaptation to climatically relevant heat sources (air or surface sea water temperature). Here, we show that non-climatic solar heating underlies thermal resistance adaptation in a rocky-eulittoral-fringe snail. Comparisons of the maximum temperatures of the air, the snail's body and the rock substratum with solar irradiance and physiological performance show that the highest body temperature is primarily controlled by solar heating and re-radiation, and that the snail's upper lethal temperature exceeds the highest climatically relevant regional air temperature by approximately 22°C. Non-climatic thermal adaptation probably features widely among marine and terrestrial ectotherms and because it could enable species to tolerate climatic rises in air temperature, it deserves more consideration in general and for inclusion into climate warming models. PMID:20375046

  13. Non-climatic thermal adaptation: implications for species' responses to climate warming

    PubMed Central

    Marshall, David J.; McQuaid, Christopher D.; Williams, Gray A.

    2010-01-01

    There is considerable interest in understanding how ectothermic animals may physiologically and behaviourally buffer the effects of climate warming. Much less consideration is being given to how organisms might adapt to non-climatic heat sources in ways that could confound predictions for responses of species and communities to climate warming. Although adaptation to non-climatic heat sources (solar and geothermal) seems likely in some marine species, climate warming predictions for marine ectotherms are largely based on adaptation to climatically relevant heat sources (air or surface sea water temperature). Here, we show that non-climatic solar heating underlies thermal resistance adaptation in a rocky–eulittoral-fringe snail. Comparisons of the maximum temperatures of the air, the snail's body and the rock substratum with solar irradiance and physiological performance show that the highest body temperature is primarily controlled by solar heating and re-radiation, and that the snail's upper lethal temperature exceeds the highest climatically relevant regional air temperature by approximately 22°C. Non-climatic thermal adaptation probably features widely among marine and terrestrial ectotherms and because it could enable species to tolerate climatic rises in air temperature, it deserves more consideration in general and for inclusion into climate warming models. PMID:20375046

  14. Method of warming cold engines in cold climates

    SciTech Connect

    Forschirm, A.

    1988-12-06

    This patent describes a method of warming cold engines in low temperature conditions comprising the steps of: (a) placing a flammable compound inside a nonflammable fabric bag; (b) placing the bag on an engine; and (c) igniting the flammable compound.

  15. African agriculture especially vulnerable to warming climate

    NASA Astrophysics Data System (ADS)

    Wendel, JoAnna

    2014-09-01

    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.

  16. Earth's Warming Climate: Are We Responsible?

    NSDL National Science Digital Library

    This tutorial provides the evidence that the amount of CO² in the atmosphere has not been as high as it is currently for nearly half a million years and that this increase corresponds with data that human activity is responsible. Learners examine scientific data showing increases in both atmospheric becomes CO² and the Earth's average temperature and analyze changes in atmospheric concentration of CO² over time. They reflect on some of the barriers involved in teaching global climate change and how using data in the classroom may be used to overcome those barriers. Multimedia resources such as video clips, a data visualization exercise featuring digital resources on climate.nasa.gov, and an interview with NASA climate scientist, Dr. Gavin Schmidt, are included. This is the second of ten self-paced professional development modules providing opportunities for teachers to learn about climate change through first-hand data exploration. Lesson plans for middle and high school students, descriptions of data collection instruments, glossary links to vocabulary are included.

  17. [Responses of Shenyang urban tree phrenology to climate warming].

    PubMed

    Xu, Wenduo; He, Xingyuan; Chen, Wei; Hu, Jianbo; Wen, Hua

    2006-10-01

    By using statistic and linear regression methods, this paper studied the last 40 years responses of Shenyang urban tree phenology to climate warming. The results showed that there was a significant correlation between the duration of tree dormancy and the mean air temperature in winter. Appropriate cold condition was beneficial to bud break, and a significant negative correlation was observed between the outset of sprouting and the mean air temperature in winter and early spring. Leaf expansion started 15 days after sprouting, which was mainly affected by the mean air temperature in spring but had no correlation with the temperature in winter. The air temperature within 20-80 days and especially 20-40 days before flowering had a significant effect on the outset of flowering, i. e. , an increasing temperature in spring could advance the outset of flowering. Both sprouting and leaf expansion were negatively correlated with cold index (CI) , but no significant correlation was observed between the outset of flowering and CI. An increase of mean annual air temperature by 1 degree C would advance the outset of sprouting by 9 days, leaf expansion by 10 days, and outset of flowering by 5 days. PMID:17209369

  18. Bering Sea conditions in the early Pliocene warm period (Invited)

    NASA Astrophysics Data System (ADS)

    Ravelo, A. C.; Takahashi, K.; Aiello, I. W.; Alvarez Zarikian, C. A.; Andreasen, D.; Aung, T. M.; Hioki, Y.; Kanematsu, Y.; Kender, S.; Lariviere, J.; Nagashima, T.; Stroynowski, Z. N.; Scientific Team Of Iodp Expedition 323

    2010-12-01

    Detailed studies of the early Pliocene warm period, approx. 3.5 - 4.5 myrs ago, and subsequent expansion of Northern Hemisphere Glaciation, provide insight into the mechanisms that explain amplified high latitude warmth. Although Pliocene surface conditions and meridional overturning circulation have been reconstructed in a few sub-Arctic and Arctic localities, IODP Expedition 323 recovered the first sediments from the Bering Sea appropriate for the study of Pliocene climate change. Early Pliocene sediments were recovered at two sites, U1340 and U1341, at the Bowers Ridge. To augment shipboard data, we generated sedimentological data (i.e., grain size, petrographic, SEM, biogenic opal analyses), and benthic assemblage counts at U1340 and U1341. We also generated diatom assemblage counts, bulk nitrogen isotope analyses, and alkenone saturation (Uk’37) analyses at U1340. Our multi-proxy approach yields the following interpretation of early Pliocene conditions: Relatively high paleoproductivity is interpreted from sedimentological data and diatom assemblage counts which indicate that the sediment is dominated by well-preserved frustules including relatively high abundances of heavily silicified diatom forms. The bulk nitrogen isotope values are relatively low, close to 2 per mil, indicating that there was an abundant supply of surface water nitrate. Sea surface temperatures were about 14 degrees, at least 5 degrees warmer than today. And, benthic foraminifera abundances are dominated by Martinottiella communis suggesting enhanced ventilation of the deep water relative to today. Considering the Bering Sea results in a global context supports the idea that the high latitude oceans were highly productive, that the global meridional temperature gradient was reduced, and that meridional overturning circulation may have been enhanced, relative to today. The warm period ended as early as 3.5 Ma, marked by gradual changes in paleoproductivity and sea surface temperature. Comparison to other paleoclimate records around the globe suggests that high and low latitude cooling were intimately connected through the Pliocene.

  19. Changes in South Pacific rainfall bands in a warming climate

    NASA Astrophysics Data System (ADS)

    Widlansky, M. J.; Timmermann, A.; Stein, K.; McGregor, S.; Schneider, N.; England, M. H.; Lengaigne, M.; Cai, W.

    2012-12-01

    The South Pacific Convergence Zone (SPCZ) is the largest rainband in the Southern Hemisphere and provides most of the rainfall to Southwest Pacific island nations. In spite of various modeling efforts, it remains uncertain how the SPCZ will respond to greenhouse warming. A multi-model ensemble average of 21st century climate change projections from the current-generation of Coupled General Circulation Models (CGCMs) suggests a slightly wetter Southwest Pacific; however, inter-model uncertainty is greater than projected rainfall changes in the SPCZ region. Using a hierarchy of climate models we show that the uncertainty of SPCZ rainfall projections in the Southwest Pacific can be explained as a result of two competing mechanisms. Higher tropical sea surface temperatures (SST) lead to an overall increase of atmospheric moisture and rainfall while weaker SST gradients dynamically shift the SPCZ northeastward (see illustration) and promote summer drying in areas of the Southwest Pacific, similar to the response to strong El Niño events. Based on a multi-model ensemble of 55 greenhouse warming experiments and for moderate tropical warming of 2-3°C we estimate a 5% decrease of SPCZ rainfall, although uncertainty exceeds ±30% among CGCMs. For stronger tropical warming, a tendency for a wetter SPCZ region is identified.; Illustration of the "warmest gets wetter" response to projected 21st century greenhouse warming. Green shading depicts observed (1982-2009) rainfall during DJF (contour interval: 2 mm/day; starting at 1 mm/day). Blue (red) contours depict warming less (more) than the tropical mean (42.5°N/S) 21st century multi-model trend (contour interval: 0.2°C; starting at ±0.1°C).

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

    PubMed

    Bernstein, Aaron S; Rice, Mary B

    2013-05-01

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

  1. [Treatment of rheumatic patients in a warm climate abroad].

    PubMed

    Forseth, Karin Øien

    2007-02-15

    Adult rheumatic and psoriatic patients in Norway have been offered state-funded treatment in a warm climate since 1976. The offer has since then been extended to other patient groups with chronic diseases. We here present a program, which mainly consists of intensive physical treatment in a warm, sunny and dry climate, for adults with chronic rheumatic disease. The article is based on available statistics and literature found by searching Medline, PubMed and Cochrane. Patients are selected for the program according to diagnosis, physical function and disease severity and activity. The majority of the patients have rheumatoid arthritis, ankylosing spondylitis or psoriatic arthritis. The treatment is demanding and is not suitable for all. There are two closing dates for applications, 1. October and 1. February. PMID:17304274

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

    NSDL National Science Digital Library

    Gavin Schmidt

    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.

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

    NASA Astrophysics Data System (ADS)

    Taniguchi, K.

    2012-12-01

    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.

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

    USGS Publications Warehouse

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

    2010-01-01

    Summer air and stream water temperatures are expected to rise in the state of Wisconsin, U.S.A., over the next 50 years. To assess potential climate warming effects on stream fishes, predictive models were developed for 50 common fish species using classification-tree analysis of 69 environmental variables in a geographic information system. Model accuracy was 56.0-93.5% in validation tests. Models were applied to all 86 898 km of stream in the state under four different climate scenarios: current conditions, limited climate warming (summer air temperatures increase 1?? C and water 0.8?? C), moderate warming (air 3?? C and water 2.4?? C) and major warming (air 5?? C and water 4?? C). With climate warming, 23 fishes were predicted to decline in distribution (three to extirpation under the major warming scenario), 23 to increase and four to have no change. Overall, declining species lost substantially more stream length than increasing species gained. All three cold-water and 16 cool-water fishes and four of 31 warm-water fishes were predicted to decline, four warm-water fishes to remain the same and 23 warm-water fishes to increase in distribution. Species changes were predicted to be most dramatic in small streams in northern Wisconsin that currently have cold to cool summer water temperatures and are dominated by cold-water and cool-water fishes, and least in larger and warmer streams and rivers in southern Wisconsin that are currently dominated by warm-water fishes. Results of this study suggest that even small increases in summer air and water temperatures owing to climate warming will have major effects on the distribution of stream fishes in Wisconsin. ?? 2010 The Authors. Journal of Fish Biology ?? 2010 The Fisheries Society of the British Isles.

  5. Foraging by forest ants under experimental climatic warming: a test at two sites

    PubMed Central

    Stuble, Katharine L; Pelini, Shannon L; Diamond, Sarah E; Fowler, David A; Dunn, Robert R; Sanders, Nathan J

    2013-01-01

    Climatic warming is altering the behavior of individuals and the composition of communities. However, recent studies have shown that the impact of warming on ectotherms varies geographically: species at warmer sites where environmental temperatures are closer to their upper critical thermal limits are more likely to be negatively impacted by warming than are species inhabiting relatively cooler sites. We used a large-scale experimental temperature manipulation to warm intact forest ant assemblages in the field and examine the impacts of chronic warming on foraging at a southern (North Carolina) and northern (Massachusetts) site in eastern North America. We examined the influence of temperature on the abundance and recruitment of foragers as well as the number of different species observed foraging. Finally, we examined the relationship between the mean temperature at which a species was found foraging and the critical thermal maximum temperature of that species, relating functional traits to behavior. We found that forager abundance and richness were related to the experimental increase in temperature at the southern site, but not the northern site. Additionally, individual species responded differently to temperature: some species foraged more under warmer conditions, whereas others foraged less. Importantly, these species-specific responses were related to functional traits of species (at least at the Duke Forest site). Species with higher critical thermal maxima had greater forager densities at higher temperatures than did species with lower critical thermal maxima. Our results indicate that while climatic warming may alter patterns of foraging activity in predictable ways, these shifts vary among species and between sites. More southerly sites and species with lower critical thermal maxima are likely to be at greater risk to ongoing climatic warming. PMID:23531642

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

    PubMed

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

    2012-09-01

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

  7. Climatic Conditions in Classrooms.

    ERIC Educational Resources Information Center

    Kevan, Simon M.; Howes, John D.

    1980-01-01

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

  8. Permafrost carbon-climate feedbacks accelerate global warming

    PubMed Central

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

    2011-01-01

    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

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

    SciTech Connect

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

    2008-09-30

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

  10. 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

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

    E-print Network

    Limpasuvan, Varavut

    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

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

    E-print Network

    Huey, Raymond B.

    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

  13. 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

  14. Auxiliary air conditioning, heating and engine warming system for trucks

    Microsoft Academic Search

    Greer

    1987-01-01

    This patent describes an air conditioning, heating and engine warming system for trucks and like vehicles comprising: an engine including a block connected to a radiator; an engine and truck air conditioning and heating system including a truck compressor, a condenser, refrigerant lines extending from the truck compressor to at least one air conditioning unit and extending from the air

  15. Carbon, Biophysics, and Climate: Where do Forests Warm? Where do Forests Cool?

    Microsoft Academic Search

    K. Caldeira; G. Bala; M. E. Wickett; T. J. Phillips; D. Lobell

    2006-01-01

    Forests store carbon and thus lower atmospheric carbon dioxide concentrations, diminishing greenhouse warming. However, forests tend to be darker than grasslands and shrublands, absorbing more solar radiation, contributing to global warming. Are forests a net warming or net cooling influence on our climate? How does this warming or cooling influence vary with latitude? To address these questions, we performed a

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

    E-print Network

    Kreinovich, Vladik

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

  17. Accelerated phenology of blacklegged ticks under climate warming.

    PubMed

    Levi, Taal; Keesing, Felicia; Oggenfuss, Kelly; Ostfeld, Richard S

    2015-04-01

    The phenology of tick emergence has important implications for the transmission of tick-borne pathogens. A long lag between the emergence of tick nymphs in spring and larvae in summer should increase transmission of persistent pathogens by allowing infected nymphs to inoculate the population of naive hosts that can subsequently transmit the pathogen to larvae to complete the transmission cycle. In contrast, greater synchrony between nymphs and larvae should facilitate transmission of pathogens that do not produce long-lasting infections in hosts. Here, we use 19 years of data on blacklegged ticks attached to small-mammal hosts to quantify the relationship between climate warming and tick phenology. Warmer years through May and August were associated with a nearly three-week advance in the phenology of nymphal and larval ticks relative to colder years, with little evidence of increased synchrony. Warmer Octobers were associated with fewer larvae feeding concurrently with nymphs during the following spring. Projected warming by the 2050s is expected to advance the timing of average nymph and larva activity by 8-11 and 10-14 days, respectively. If these trends continue, climate warming should maintain or increase transmission of persistent pathogens, while it might inhibit pathogens that do not produce long-lasting infections. PMID:25688016

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

    Microsoft Academic Search

    James C. Chatters; Virginia L. Butler; Michael J. Scott; David M. Anderson; Duane A. Neitzel

    1992-01-01

    To understand how climatic warming might affect salmonid populations, we are following a four-step procedure, incorporating paleoenvironmental data at the beginning and ending points, as follows. First, we used geomorphic, paleobotanical, and paleomalacological data to reconstruct stream conditions during the last 8000 years. Second, we estimated the effect on salmon of conditions extant approximately 6000 to 7000 radiocarbon years before

  19. THE COMPOUNDING EFFECTS OF TROPICAL DEFORESTATION AND GREENHOUSE WARMING ON CLIMATE

    Microsoft Academic Search

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

    2001-01-01

    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

  20. Midlatitude Ocean-Atmosphere Interactions in a Warming Climate

    NASA Astrophysics Data System (ADS)

    Hand, Ralf; Keenlyside, Noel S.; Greatbatch, Richard J.; Omrani, Nour-Eddine

    2014-05-01

    Recent studies have shown that mid-latitude regions with strong SST gradients as they can be found in the Gulf Stream and it's extension are a key-region for midlatitude ocean-atmosphere interactions; SST variability on inter-annual to decadal timescales in this region has a distinct impact on the overlying atmosphere. Climate projections with coupled general circulation models show strong indications, that the strength and the shape of the ocean circulation might underly crucial changes in a warming climate. This work presents an analysis of the atmospheric part of a long-term (covering the period until 2300) RCP 8.5 scenario run of a coupled general circulation model (MPI-ESM-LR) with focus on the North Atlantic. The ocean component of the model shows a strong decrease in the meridional overturning circulation and a northward-shift of the boundary between the subpolar and the subtropical gyre. This leads to significant changes of the ocean surface conditions in the Gulf Stream and the Gulf Stream extension. The weakened MOC and the northward shift of the SST front leads to a weakening of the SST gradients in the historical Gulf Stream area and a strengthening of the gradients east of Newfoundland. We analysed the impact of the changes in the ocean on precipitation, a quantity which has been shown to be highly sensitive to the position of the SST front and the absolute value of SST in that region in previous studies. In winter the model shows a large region with strongly enhanced precipitation southeast off Newfoundland, likely related to a slight intensification of the North-Atlantic storm track present in the future projection. In summer the most prominent feature in terms of precipitation is a decrease in the region off the US east coast, where the historical control experiment had the strongest SST gradients, but shows weaker gradients in the future. A preliminary analysis of the hydrological cycle gives indications, that the precipitation changes are induced by a combination of (globally) warmer air temperatures enhancing the hydrological cycle and an effect due to shifted ocean surface patterns. Sensitivity experiments with the atmospheric component of the model are being performed to separate and quantify these two effects better.

  1. Winter season mortality: will climate warming bring benefits?

    NASA Astrophysics Data System (ADS)

    Kinney, Patrick L.; Schwartz, Joel; Pascal, Mathilde; Petkova, Elisaveta; Le Tertre, Alain; Medina, Sylvia; Vautard, Robert

    2015-06-01

    Extreme heat events are associated with spikes in mortality, yet death rates are on average highest during the coldest months of the year. Under the assumption that most winter excess mortality is due to cold temperature, many previous studies have concluded that winter mortality will substantially decline in a warming climate. We analyzed whether and to what extent cold temperatures are associated with excess winter mortality across multiple cities and over multiple years within individual cities, using daily temperature and mortality data from 36 US cities (1985–2006) and 3 French cities (1971–2007). Comparing across cities, we found that excess winter mortality did not depend on seasonal temperature range, and was no lower in warmer vs. colder cities, suggesting that temperature is not a key driver of winter excess mortality. Using regression models within monthly strata, we found that variability in daily mortality within cities was not strongly influenced by winter temperature. Finally we found that inadequate control for seasonality in analyses of the effects of cold temperatures led to spuriously large assumed cold effects, and erroneous attribution of winter mortality to cold temperatures. Our findings suggest that reductions in cold-related mortality under warming climate may be much smaller than some have assumed. This should be of interest to researchers and policy makers concerned with projecting future health effects of climate change and developing relevant adaptation strategies.

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

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

    PubMed

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

    2015-01-01

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

  4. 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

    Shijin Wang; Yuanqing He; Xiaodong Song

    2010-01-01

    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

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

    PubMed

    Donnelly, Alison; Yu, Rong; Liu, Lingling

    2015-08-01

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

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

    SciTech Connect

    Rudd, A.

    2014-10-01

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

  7. Typhoon and storm surge intensity changes under the warming climate around Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Oh, Sang Myeong; Moon, Il-Ju

    2014-05-01

    This study investigates the intensity change in typhoons and storm surges surrounding the Korean Peninsula under global warming conditions as obtained from the MPI_ECHAM5 climate model using the A1B series. The authors use the Cyclostationary Empirical Orthogonal Function to estimate future background fields for typhoon simulations from twenty-first-century prediction results. A series of numerical experiments applies WRF (Weather Research and Forecasting) and POM (Prinston Ocean Model) models to simulate two historical typhoons, Maemi (2003) and Rusa (2002), and associated storm surges under real historical and future warming conditions. Applying numerical experiments to two typhoons, this study found that their central pressure dropped about 19 and 17 hPa, respectively, when considering the future sea surface temperature (a warming of 3.9 K for 100 years) over the East China Sea (Exp. 1). The associated enhancement of storm surge height ranged from 16 to 67 cm along the southern coast of the Korean Peninsula. However, when the study considered global warming conditions for other atmospheric variables such as sea-level pressure, air temperature, relative humidity, geopotential height, and wind in the typhoon simulations (Exp. 2), the intensities of the two typhoons and their associated surge heights scarcely increased compared to the results of Exp. 1. Analyzing projected atmospheric variables, the authors found that air temperatures at the top of the storm around 200 hPa increased more than those at the surface in tropical and mid-latitudes. The reduced vertical temperature difference provided an unfavorable condition in the typhoon's development even under conditions of global warming. This suggests that global warming may not always correlate with a large increase in the number of intense cyclones and/or an increase in associated storm surges.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  9. Climatic warming and increased malaria incidence in Rwanda.

    PubMed

    Loevinsohn, M E

    1994-03-19

    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

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

    PubMed Central

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

    2013-01-01

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

  11. Terrestrial carbon-cycle feedback to climate warming: experimental evidence on plant regulation and impacts of biofuel feedstock harvest

    Microsoft Academic Search

    YIQI LUO; REBECCA SHERRY; XUHUI ZHOU; SHIQIANG WAN

    2009-01-01

    Feedback between global carbon (C) cycles and climate change is one of the major uncertainties in projecting future global warming. Coupled carbon-climate models all demonstrated a positive feedback between terrestrial C cycle and climate warming. The positive feedback results from decreased net primary production (NPP) in most models and increased respiratory C release by all the models under climate warming.

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

    PubMed Central

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

    2015-01-01

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

  13. Multisectoral Climate Impact Hotspots in a Warming World

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  14. Little Ice Age wintertime climate cooling linked to N-Atlantic subpolar gyre warming

    NASA Astrophysics Data System (ADS)

    Kuijpers, Antoon; Seidenkrantz, Marit-Solveig; Sicre, Marie-Alexandrine; Andresen, Camilla S.; Staines-Urías, Francisca

    2015-04-01

    Traditionally, the Little Ice Age (LIA) in the North Atlantic is believed to have been marked by negative Sea Surface Temperature (SST) anomalies. In apparent contrast, we present evidence from sediment core records from the N-Atlantic Subpolar Gyre showing prevalence of warm SST conditions. Our proxy data include both alkenone-based SST reconstructions and results from faunal and geochemical foraminiferal studies. Subpolar Gyre SST warming after the Medieval Climate Anomaly is observed in the Labrador Current close to the Gulf Stream boundary off Newfoundland, which agrees with previously reported increased influence of warmer, Gulf Stream-derived Slope Water off southern Newfoundland(1). Our core records from the West- and East Greenland Current realm off southern Greenland, as well as sites in Faroese waters, correspondingly indicate increased influence of warm, saline North Atlantic / Irminger Current waters. Other recently published studies also report LIA SST warming in the northern subpolar North Atlantic(2) as well as increased heat transport into the Arctic via the West Spitsbergen Current(3). Growing evidence indicates that positive SST anomalies in the North Atlantic Ocean can promote negative NAO conditions, thus be linked with cold wintertime conditions in Northwestern Europe. A published modeling study using ensemble simulations with an atmospheric GCM forced with reconstructed SST data for the period 1871-1999 shows weakening of the westerly winds around 60o N with SST anomalies that have the same sign across the North Atlantic(4). Six other climate models show that with some years of delay, an intensified Atlantic Meridional Overturning Circulation leads to a weak negative North Atlantic Oscillation (NAO) phase during winter(5). Furthermore, it was recently found that the stratosphere is a key element of extra-tropical response to ocean variability. Observational analysis and atmospheric model experiments indicate that large-scale Atlantic Ocean warming drives high-latitude precursory stratospheric warming in the first part of the winter, which propagates downward and leads to a negative tropospheric NAO(6). In summary, our results in combination with other proxy records and modelling experiments are consistent with a prevailing NAO negative atmospheric circulation mode and thus relate LIA continental wintertime cooling to a relatively warm N-Atlantic Subpolar Gyre, a scenario which may have implications for ongoing and future ocean warming conditions. (1) Keigwin,LD,Pickart,RS(1999) Science 286,520-523 (2) Miettinen,A et al(2012) J Climate, doi:10.1175/JCLI-D-11-00581.1 (3) Spielhagen,R et al (2011) Science 331, 450-453 (4) Sutton,RT,Hodson,DLR (2003) J Climate 16, 3296-3313 (5) Gastineau, G, Frankignoul, C (2011) Climate Dynamics 39, 37-57 (6) Omrani, N.-E. et al (2014) Climate Dynamics 42, 649-663

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    E-print Network

    Kleypas, Joanie

    an empirical model for predicting chlorophyll from the physical properties of the global warming simulations. Four features stand out in the response to global warming: (1) a drop in chlorophyll in the North ecosystems to climate warming, Global Biogeochem. Cycles, 18, GB3003, doi:10.1029/2003GB002134. 1

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

    E-print Network

    Fischlin, Andreas

    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

  18. Thermal Comfort of Naturally Ventilated Buildings in Warm-Humid Climates: field survey

    Microsoft Academic Search

    Abel Tablada; Ana M. De la Peña; Frank De Troyer

    Several studies have shown lately that the international comfort standards for buildings and the related predictions models report a warmer sensation than the occupants report in the case of naturally ventilated buildings in warm climates. This paper exposes some aspects of the debate in the field of thermal comfort in n aturally ventilated buildings located in warm and humid climates.

  19. 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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  1. 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

  2. An explanation for the difference between twentieth and twenty-first century land-sea warming ratio in climate models

    NASA Astrophysics Data System (ADS)

    Joshi, M. M.; Lambert, F. H.; Webb, M. J.

    2013-10-01

    A land-sea surface warming ratio (or ?) that exceeds unity is a robust feature of both observed and modelled climate change. Interestingly, though climate models have differing values for ?, it remains almost time-invariant for a wide range of twenty-first century climate transient warming scenarios, while varying in simulations of the twentieth century. Here, we present an explanation for time-invariant land-sea warming ratio that applies if three conditions on radiative forcing are met: first, spatial variations in the climate forcing must be sufficiently small that the lower free troposphere warms evenly over land and ocean; second, the temperature response must not be large enough to change the global circulation to zeroth order; third, the temperature response must not be large enough to modify the boundary layer amplification mechanisms that contribute to making ? exceed unity. Projected temperature changes over this century are too small to breach the latter two conditions. Hence, the mechanism appears to show why both twenty-first century and time-invariant CO2 forcing lead to similar values of ? in climate models despite the presence of transient ocean heat uptake, whereas twentieth century forcing—which has a significant spatially confined anthropogenic tropospheric aerosol component that breaches the first condition—leads to modelled values of ? that vary widely amongst models and in time. Our results suggest an explanation for the behaviour of ? when climate is forced by other regionally confined forcing scenarios such as geo-engineered changes to oceanic clouds. Our results show how land-sea contrasts in surface and boundary layer characteristics act in tandem to produce the land-sea surface warming contrast.

  3. Climate warming revealed by englacial temperatures at Col du Dôme (4250 m, Mont Blanc area)

    NASA Astrophysics Data System (ADS)

    Vincent, Christian; Le Meur, Emmanuel; Six, Delphine; Possenti, Philippe; Lefebvre, Eric; Funk, Martin

    2007-08-01

    Temperatures were measured in two deep boreholes drilled at the same location in the ice at Col du Dôme (4250 m) in 1994 and 2005, providing clear evidence of atmospheric warming. The 1994 temperature profile was already far from steady state conditions. Results from a heat transfer model reveal that the englacial temperature increase cannot be explained solely by atmospheric temperature rise. The latent heat produced by the refreezing of surface meltwater below the surface also contributes to the englacial temperature increase. Although surface melting is normally very low at this altitude, this contribution became significant after 1980 for temperatures at the top of the borehole. Simulations for different climatic scenarios show that glaciated areas located between 3500 and 4250 m could become temperate in the future. This warming could have a major impact on the stability of hanging glaciers frozen to their beds if the melting point is reached.

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

    NASA Astrophysics Data System (ADS)

    McDowell, Nathan G.; Allen, Craig D.

    2015-07-01

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

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

    E-print Network

    Wirosoetisno, Djoko

    Impact of climate change on stratospheric sudden warmings as simulated by the Canadian middle midwinter stratospheric sudden warmings (SSWs) are ex- amined using transient climate change simulations$593157392 CentAUR 7326E125C427E3E3C7E84272B43&E#E97D4$ 97D4$4BE27B725CE9393BE647 #12;Impact of Climate Change

  6. Projection of Summer Climate on Tokyo Metropolitan Area using Pseudo Global Warming Method

    NASA Astrophysics Data System (ADS)

    Adachi, S. A.; Kimura, F.; Kusaka, H.; Hara, M.

    2010-12-01

    Recent surface air temperature observations in most of urban areas show the remarkable increasing trend affected by the global warming and the heat island effects. There are many populous areas in Japan. In such areas, the effects of land-use change and urbanization on the local climate are not negligible (Fujibe, 2010). The heat stress for citizen there is concerned to swell moreover in the future. Therefore, spatially detailed climate projection is required for making adaptation and mitigation plans. This study focuses on the Tokyo metropolitan area (TMA) in summer and aims to estimate the local climate change over the TMA in 2070s using a regional climate model. The Regional Atmospheric Modeling System (RAMS) was used for downscaling. A single layer urban canopy model (Kusaka et al., 2001) is built into RAMS as a parameterization expressing the features of urban surface. We performed two experiments for estimating present and future climate. In the present climate simulation, the initial and boundary conditions for RAMS are provided from the JRA-25/JCDAS. On the other hand, the Pseudo Global Warming (PGW) method (Sato et al., 2007) is applied to estimate the future climate, instead of the conventional dynamical downscaling method. The PGW method is expected to reduce the model biases in the future projection estimated by Atmosphere-Ocean General Circulation Models (AOGCM). The boundary conditions used in the PGW method is given by the PGW data, which are obtained by adding the climate monthly difference between 1990s and 2070s estimated by AOGCMs to the 6-hourly reanalysis data. In addition, the uncertainty in the regional climate projection depending on the AOGCM projections is estimated from additional downscaling experiments using the different PGW data obtained from five AOGCMs. Acknowledgment: This work was supported by the Global Environment Research Fund (S-5-3) of the Ministry of the Environment, Japan. References: 1. Fujibe, F., Int. J. Climatol., doi:10.1002/joc.2142 (2010). 2. Kusaka, H., H. Kondo, Y. Kikegawa, and F. Kimura, Bound.-Layer Meteor., 101, 329-358 (2001). 3. Sato, T., F. Kimura, and A. Kitoh, J. Hydrology, 144-154 (2007).

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

    E-print Network

    Schaetzl, Randall

    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

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

    Microsoft Academic Search

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

    2010-01-01

    Long term studies of vegetation change throughout the tundra biome show increases in the height, canopy extent and dominance of vascular vegetation versus bryophytes and lichens, with mixed responses of the dominant shrub and graminoid growth forms. Increases in vascular vegetation are recorded for sites with and without measurable climatic warming over recent decades, but with other potential drivers, i.e.,

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

    E-print Network

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

    2015-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  11. Trend analysis of wet and dry climatic conditions for the Carpathian basin using RCM simulations

    Microsoft Academic Search

    Orsolya Torek; Judit Bartholy; Rita Pongracz; Brigitta Hollosi; Ildiko Pieczka

    2010-01-01

    Global warming may be recognized both in shifts of regional mean climate, and also, in the frequency and intensity changes of different climatological extremes associated to both temperature and precipitation. In this poster the main focus is on the analysis of precipitation-related climatic conditions. For this purpose we use different types of drought indices, namely, precipitation index, standardized precipitation anomaly

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  13. Assessing orbitally-forced interglacial climate variability during the mid-Pliocene Warm Period

    NASA Astrophysics Data System (ADS)

    Prescott, Caroline L.; Haywood, Alan M.; Dolan, Aisling M.; Hunter, Stephen J.; Pope, James O.; Pickering, Steven J.

    2014-08-01

    The traditional view of the Pliocene is one of an epoch with higher than present global mean annual temperatures (?2 to 3 °C) and stable climate conditions. Published data-model comparisons for the mid-Pliocene Warm Period (mPWP: ?3.3 to 3 million years ago) have identified specific regions of concordance and discord between climate model outputs and marine/terrestrial proxy data. Due to the time averaged nature of global palaeoenvironmental syntheses, it has been hypothesised that climate variability during interglacial events within the mPWP could contribute to site-specific data/model disagreement. The Hadley Centre Coupled Climate Model Version 3 (HadCM3) is used to assess the nature of climate variability around two interglacial events within the mPWP that have different characteristics of orbital forcing (Marine Isotope Stages KM5c and K1). Model results indicate that ±20 kyr on either side of the MIS KM5c, orbital forcing produced a less than 1 °C change in global mean annual temperatures. Regionally, mean annual surface air temperature (SAT) variability can reach 2 to 3 °C. Seasonal variations exceed those predicted for the annual mean and can locally exceed 5 °C. Simulations 20 kyr on either side of MIS K1 show considerably increased variability in relation to KM5c. We demonstrate that orbitally-forced changes in surface air temperature during interglacial events within the mPWP can be substantial, and could therefore contribute to data/model discord. This is especially likely if proxies preserve growing season rather than mean annual temperatures. Model results indicate that peak MIS KM5c and K1 interglacial temperatures were not globally synchronous, highlighting leads and lags in temperature in different regions. This highlights the potential pitfalls in aligning peaks in proxy-derived temperatures across geographically diverse data sites, and indicates that a single climate model simulation for an interglacial event is inadequate to capture peak temperature change in all regions. We conclude that the premise of sustained global warmth and stable Pliocene climate conditions is incomplete. We also contend that the likely nature of Pliocene interglacial climate variability is more akin to interglacial events within the Quaternary, where the character of interglacials is known to be diverse. In the future, the utility of Pliocene data/model comparisons is dependent upon 1) establishing precise chronology of the proxy data, 2) providing climate models with fully proxy-consistent boundary conditions and 3) in utilising ensembles of climate simulations that can adequately capture orbital variability around any studied interval.

  14. Implications for the creation of warm saline deep water: Late Paleocene reconstructions and global climate model simulations

    SciTech Connect

    O`Connell, S. [Wesleyan Univ., Middletown, CT (United States)] [Wesleyan Univ., Middletown, CT (United States); Chandler, M.A. [Columbia Univ., New York, NY (United States)] [Columbia Univ., New York, NY (United States); [Goddard Inst. of Space Studies, New York, NY (United States); Ruedy, R. [Goddard Inst. of Space Studies, New York, NY (United States)] [Goddard Inst. of Space Studies, New York, NY (United States)

    1996-03-01

    A global warming trend began during the late Paleocene that culminated in the early Eocene with the highest global temperatures of the Cenozoic. We have reconstructed late Paleocene surfacial boundary conditions and modeled atmospheric conditions using the Goddard Institute for Space Studies general circulation model version II (GISS GCM II). These experiments were conducted to test the hypothesis that warm saline deep water formed during the late paleocene and to understand atmospheric circulation near the beginning of a period of global warming. The warming is attributed primarily to increased sea surface temperatures at high latitudes. The sensitivity of the climate to ocean temperature was tested using two sea surface temperature distributions, each delimited latitudinally by oxygen isotope values, but with different east-west gradients. The simulations discussed here contain several features unique among warm climate experiments. The first experiment (P-1) used latitudinally constant (zonal) sea surface temperatures. The zonally distributed sea surface temperatures strengthen the general circulation of the atmosphere. In particular, Hadley Cell circulation is intensified, leading to extremes of precipitation in the equatorial region and extreme evaporation across subtropical oceans. The unusual results prompted a second experiment with modern east-west sea surface temperature gradients superimposed and referred to as P-Gradient (P-Grad). 84 refs., 10 figs., 4 tabs.

  15. The variation of warm pool in the equatorial western pacific and its impacts on climate

    Microsoft Academic Search

    Chongyin Li; Mingquan Mu; Guangqing Zhou

    1999-01-01

    The variation of warm pool ocean temperature in the equatorial western Pacific and its impacts on climatic change are studied\\u000a in the present paper. The SSTs in the warm pool region not only have seasonal variation but also have interannual variation\\u000a more clearly; The influence of anomalies of SST in the warm pool region on the East Asian monsoon is

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

    E-print Network

    Henley, Sian Frances

    2013-07-01

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

  17. 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

  18. LandOcean Warming Contrast over a Wide Range of Climates: Convective Quasi-Equilibrium Theory

    E-print Network

    increase at a greater rate over land than ocean in simulations and observations of global warming. It hasLand­Ocean Warming Contrast over a Wide Range of Climates: Convective Quasi-Equilibrium Theory Program on the Science and Policy of Global Change combines cutting-edge scientific research

  19. Simulated increase of hurricane intensities in a COâ-warmed climate

    Microsoft Academic Search

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

    1998-01-01

    Hurricanes can inflict catastrophic property damage and loss of human life. Thus, it is important to determine how the character of these powerful storms could change in response to greenhouse gas-induced global warming. The impact of climate warming on hurricane intensities was investigated with a regional, high-resolution, hurricane prediction model. In a case study, 51 western Pacific storm cases under

  20. Subtropical climate change during the Pliocene warm period- The strong role of eccentricity and precessional forcing modulation during equable climates

    NASA Astrophysics Data System (ADS)

    Caballero Gill, R. P.; Herbert, T.

    2012-12-01

    The Pliocene Epoch (5.3-1.8 Ma) is the most recent geologic period of sustained global warmth. Understanding how the world responded to these warmer conditions has important implications as an analog for future anthropogenic warming of the Earth. Past climate reconstructions of the Pliocene warm period (pWP, 4-3 Ma) suggest that mean annual temperatures were approximately 3°C warmer than present, although reconstructions from the Southern Hemisphere (SH) are sparse. The Southern Ocean plays a key role in regulating global climate, so high-resolution reconstructions from this region are important for understanding global climate processes. These processes include climate-ice-sea level interactions, as significant continental ice was only found in the Southern Hemisphere during the pWP. Very little is understood about SH ocean dynamics and climate variability under the unipolar climate conditions of the pWP. Of particular interest are the links between sea surface temperatures (SSTs) and orbital forcing of the unipolar ice sheet dynamics and changes in intermediate water mass properties via ?18O affecting the heat transport under warmer climate. We will present high-resolution (~2.5 kyr sample resolution) records of climate change in the surface and intermediate waters (1365 m. water depth) of the Southwest Pacific (ODP site 1125) during the pWP. Average alkenone-derived SSTs for the pWP at site ODP 1125 are warmer (18.6 °C) than Holocene SSTs in the region (16.3 °C, using multiple proxies for the last 10 kyr) as well as warmer than modern oceanographic data (14.6 °C). The glacial to interglacial temperatures observed in the pWP at ODP 1125 have a smaller range (21.0-15.5 °C) compared to glacial-interglacial temperatures observed in the late Pleistocene (18.0-11.5 °C) in the region, highlighting the reduced orbital-scale variability of subtropical surface waters during the pWP. Available datasets of pWP SSTs show that the reduced orbital-scale variability of surface waters is greater in the tropical regions by almost two-fold compared to higher latitudes. This high contrast of tropical versus higher latitude variability may indicate a more active role of the higher latitudes in re-distributing heat at the glacial-interglacial scales or that feedbacks at high latitudes are stronger relative to tropics in pWP relative to late Pleistocene. Our findings provide evidence for eccentricity and precessional forcing modulating the ?18O of benthic foraminifera at ODP 1125 and to a lesser degree the SSTs, while the obliquity response is not as prevalent on either surface or intermediate water signals. Relative contributions of eccentricity-precession and obliquity are higher at ODP 1125 compared to global benthic isotope stacks, underscoring the need for more high-resolution records, in the hemisphere with most ice, to detangle the controls (temperature vs. ice volume) in the benthic isotope record. Our findings of high eccentricity and precessional response in the ?18O of intermediate waters provide support for a strong control of the seasonal contrast in intermediate water formation during past warm climates.

  1. Persistent Cold Air Outbreaks over North America Under Climate Warming

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Leung, L. R.; Lu, J.

    2014-12-01

    This study evaluates the change of cold air outbreaks (CAO) over North America using Coupled Model Intercomparison Project Phase 5 (CMIP5) multi-model ensemble of global climate simulations as well as regional high resolution climate simulations. In future, while robust decrease of CAO duration dominates in most of the North America, the decrease over northwestern U.S. was found to have much smaller magnitude than the surrounding regions. We found statistically significant increase of the sea level pressure over gulf of Alaska, leading to the advection of cold air to northwestern U.S.. By shifting the probability distribution of present temperature towards future warmer conditions, we identified the changes in large scale circulation contribute to about 50% of the enhanced sea level pressure. Using the high resolution regional climate model results, we found that increases of existing snowpack could potentially trigger the increase of CAO in the near future over the southwestern U.S. and Rocky Mountain through surface albedo effects. By the end of this century, the top 5 most extreme historical CAO events may still occur and wind chill warning will continue to have societal impacts over North America in particular over northwestern United States.

  2. Local forcings affect lake zooplankton vulnerability and response to climate warming.

    PubMed

    Alric, Benjamin; Jenny, Jean-Philippe; Berthon, Vincent; Arnaud, Fabien; Pignol, Cecile; Reyss, Jean-Louis; Sabatier, Pierre; Perga, Marie-Elodie

    2013-12-01

    While considerable insights on the ecological consequences of climate change have been gained from studies conducted on remote lakes, little has been done on lakes under direct human exposure. Ecosystem vulnerability and responses to climate warming might yet largely depend on the ecological state and thus on local anthropogenic pressures. We tested this hypothesis through a paleolimnological approach on three temperate large lakes submitted to rather similar climate warming but varying intensities of analogous local forcings (changes in nutrient inputs and fisheries management practices). Changes in the structure of the cladoceran community were considered as revealing for alterations, over the time, of the pelagic food web. Trajectories of the cladoceran communities were compared among the three study lakes (Lakes Geneva, Bourget, and Annecy) over the last 70-150 years. Generalized additive models were used to develop a hierarchical understanding of the respective roles of local stressors and climate warming in structuring cladoceran communities. The cladoceran communities were not equally affected by climate warming between lakes. In Lake Annecy, which is the most nutrient-limited, the cladoceran community was essentially controlled by local stressors, with very limited impact of climate. In contrast, the more nutrient-loaded Lakes Geneva and Bourget were more sensitive to climate warming, although the magnitude of their responses and the pathways under which climate warming affected the communities varied between the two lakes. Finally, our results demonstrated that lake vulnerability and responses to climate warming are modulated by lake trophic status but can also be altered by fisheries management practices through changes in fish predation pressure. PMID:24597223

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  4. Testing paradigms of ecosystem change under climate warming in Antarctica.

    PubMed

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

    2013-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

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

    Microsoft Academic Search

    J. O. Stireman III; L. A. Dyer; D. H. Janzen; M. S. Singer; J. T. Lill; R. J. Marquis; R. E. Ricklefs; G. L. Gentry; W. Hallwachs; P. D. Coley; J. A. Barone; H. F. Greeney; H. Connahs; P. Barbosa; H. C. Morais; I. R. Diniz

    2005-01-01

    Insect outbreaks are expected to increase in frequency and intensity with projected changes in global climate through direct effects of climate change on insect populations and through disruption of community interactions. Although there is much concern about mean changes in global climate, the impact of climatic variability itself on species interactions has been little explored. Here, we compare caterpillar-parasitoid interactions

  7. Anticipated Climate Warming Effects on Bull Trout Habitats and Populations Across the Interior Columbia River Basin

    Microsoft Academic Search

    Bruce E. Rieman; Daniel Isaak; Susan Adams; Dona Horan; David Nagel; Charles Luce; Deborah Myers

    2007-01-01

    A warming climate could profoundly affect the distribution and abundance of many fishes. Bull trout Salvelinus confluentus may be especially vulnerable to climate change given that spawning and early rearing are constrained by cold water temperatures creating a patchwork of natal headwater habitats across river networks. Because the size and connectivity of patches also appear to influence the persistence of

  8. The Dynamic Response of the Greenland and Antarctic Ice Sheets to Multiple-Century Climatic Warming

    Microsoft Academic Search

    Philippe Huybrechts; Jan de Wolde

    1999-01-01

    New calculations were performed to investigate the combined response of the Greenland and Antarctic ice sheets to a range of climatic warming scenarios over the next millennium. Use was made of fully dynamic 3D thermomechanic ice sheet models, which were coupled to a two-dimensional climate model. The experiments were initialized with simulations over the last two glacial cycles to estimate

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

    Microsoft Academic Search

    Gowri Koneswaran; Danielle Nierenberg

    2008-01-01

    Background: The farm animal sector is the single largest anthropogenic user of land, contributing to many environmental problems, including global warming and climate change. Objectives: The aim of this study was to synthesize and expand upon existing data on the contribution of farm animal production to climate change. Methods: We analyzed the scientific literature on farm animal production and documented

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

    ERIC Educational Resources Information Center

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

    2010-01-01

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

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

    PubMed

    Davis, Lucas W; Gertler, Paul J

    2015-05-12

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

  12. Areas of potential suitability and survival of Dendroctonus valens in china under extreme climate warming scenario.

    PubMed

    He, S Y; Ge, X Z; Wang, T; Wen, J B; Zong, S X

    2015-08-01

    The areas in China with climates suitable for the potential distribution of the pest species red turpentine beetle (RTB) Dendroctonus valens LeConte (Coleoptera: Scolytidae) were predicted by CLIMEX based on historical climate data and future climate data with warming estimated. The model used a historical climate data set (1971-2000) and a simulated climate data set (2010-2039) provided by the Tyndall Centre for Climate Change (TYN SC 2.0). Based on the historical climate data, a wide area was available in China with a suitable climate for the beetle in which every province might contain suitable habitats for this pest, particularly all of the southern provinces. The northern limit of the distribution of the beetle was predicted to reach Yakeshi and Elunchun in Inner Mongolia, and the western boundary would reach to Keerkezi in Xinjiang Province. Based on a global-warming scenario, the area with a potential climate suited to RTB in the next 30 years (2010-2039) may extend further to the northeast. The northern limit of the distribution could reach most parts of south Heilongjiang Province, whereas the western limit would remain unchanged. Combined with the tendency for RTB to spread, the variation in suitable habitats within the scenario of extreme climate warming and the multiple geographical elements of China led us to assume that, within the next 30 years, RTB would spread towards the northeast, northwest, and central regions of China and could be a potentially serious problem for the forests of China. PMID:25895594

  13. Climate warming and agricultural stressors interact to determine stream macroinvertebrate community dynamics.

    PubMed

    Piggott, Jeremy J; Townsend, Colin R; Matthaei, Christoph D

    2015-05-01

    Global climate change is likely to modify the ecological consequences of currently acting stressors, but potentially important interactions between climate warming and land-use related stressors remain largely unknown. Agriculture affects streams and rivers worldwide, including via nutrient enrichment and increased fine sediment input. We manipulated nutrients (simulating agricultural run-off) and deposited fine sediment (simulating agricultural erosion) (two levels each) and water temperature (eight levels, 0-6°C above ambient) simultaneously in 128 streamside mesocosms to determine the individual and combined effects of the three stressors on macroinvertebrate community dynamics (community composition and body size structure of benthic, drift and insect emergence assemblages). All three stressors had pervasive individual effects, but in combination often produced additive or antagonistic outcomes. Changes in benthic community composition showed a complex interplay among habitat quality (with or without sediment), resource availability (with or without nutrient enrichment) and the behavioural/physiological tendency to drift or emerge as temperature rose. The presence of sediment and raised temperature both resulted in a community of smaller organisms. Deposited fine sediment strongly increased the propensity to drift. Stressor effects were most prominent in the benthic assemblage, frequently reflected by opposite patterns in individuals quitting the benthos (in terms of their propensity to drift or emerge). Of particular importance is that community measures of stream health routinely used around the world (taxon richness, EPT richness and diversity) all showed complex three-way interactions, with either a consistently stronger temperature response or a reversal of its direction when one or both agricultural stressors were also in operation. The negative effects of added fine sediment, which were often stronger at raised temperatures, suggest that streams already impacted by high sediment loads may be further degraded under a warming climate. However, the degree to which this will occur may also depend on in-stream nutrient conditions. PMID:25581853

  14. Climate Conditioning for the Learning Environment.

    ERIC Educational Resources Information Center

    Perkins and Will, Architects, Chicago, IL.

    Discusses heating, cooling, and ventilation for the classroom in relationship to students' learning abilities. It is designed to assist school boards, administrators, architects and engineers in understanding the beneficial effects of total climate control, and in evaluating the climate conditioning systems available for schools. Discussion…

  15. Shifting suitability for malaria vectors across Africa with warming climates

    E-print Network

    Peterson, A. Townsend

    2009-05-10

    species in Africa over the coming 50 years, based on ecological niche model projections over two global climate models, two scenarios of climate change, and detailed spatial summaries of human population distributions. Results For both species, under all...

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

    NASA Astrophysics Data System (ADS)

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

    2009-05-01

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

  17. Linking global warming to amphibian declines through its effects on female body condition and survivorship.

    PubMed

    Reading, C J

    2007-02-01

    There is general consensus that climate change has contributed to the observed decline, and extinction, of many amphibian species throughout the world. However, the mechanisms of its effects remain unclear. A laboratory study in 1980-1981 in which temperate zone amphibians that were prevented from hibernating had decreased growth rates, matured at a smaller size and had increased mortality compared with those that hibernated suggested one possible mechanism. I used data from a field study of common toads (Bufo bufo) in the UK, between 1983 and 2005, to determine whether this also occurs in the field. The results demonstrated two pathways by which global warming may cause amphibian declines. First, there was a clear relationship between a decline in the body condition of female common toads and the occurrence of warmer than average years since 1983. This was paralleled by a decline in their annual survival rates with the relationship between these two declines being highly correlated. Second, there was a significant relationship between the occurrence of mild winters and a reduction in female body size, resulting in fewer eggs being laid annually. Climate warming can, therefore, act on wild temperate zone amphibians by deleteriously affecting their physiology, during and after hibernation, causing increased female mortality rates and decreased fecundity in survivors. PMID:17024381

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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.

  19. CLIMATIC CONDITIONS IMPACT ON CANOLA CULTURAL PLANT GROWING IN TURKEY

    Microsoft Academic Search

    Beyza KAYMAZ

    Negative effect of climate conditions affecting many sectors ahead being agriculture on agricultural activities is felt in our country as well where global climate change is experienced. This situation needs breeding of alternative plants stronger than other products against to climate conditions, having multiple usage areas. By this aim; relation between special climate conditions of canola plant and climate conditions

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

    USGS Publications Warehouse

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

    2004-01-01

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

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

    USGS Publications Warehouse

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

    2013-01-01

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

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  4. Are treelines advancing? A global meta-analysis of treeline response to climate warming.

    PubMed

    Harsch, Melanie A; Hulme, Philip E; McGlone, Matt S; Duncan, Richard P

    2009-10-01

    Treelines are temperature sensitive transition zones that are expected to respond to climate warming by advancing beyond their current position. Response to climate warming over the last century, however, has been mixed, with some treelines showing evidence of recruitment at higher altitudes and/or latitudes (advance) whereas others reveal no marked change in the upper limit of tree establishment. To explore this variation, we analysed a global dataset of 166 sites for which treeline dynamics had been recorded since 1900 AD. Advance was recorded at 52% of sites with only 1% reporting treeline recession. Treelines that experienced strong winter warming were more likely to have advanced, and treelines with a diffuse form were more likely to have advanced than those with an abrupt or krummholz form. Diffuse treelines may be more responsive to warming because they are more strongly growth limited, whereas other treeline forms may be subject to additional constraints. PMID:19682007

  5. Boron Nutrition and Chilling Tolerance of Warm Climate Crop Species

    PubMed Central

    HUANG, LONGBIN; YE, ZHENGQIAN; BELL, RICHARD W.; DELL, BERNARD

    2005-01-01

    • Background Field observations and glasshouse studies have suggested links between boron (B)-deficiency and leaf damage induced by low temperature in crop plants, but causal relationships between these two stresses at physiological, biochemical and molecular levels have yet to be explored. Limited evidence at the whole-plant level suggests that chilling temperature in the root zone restricts B uptake capacity and/or B distribution/utilization efficiency in the shoot, but the nature of this interaction depends on chilling tolerance of species concerned, the mode of low temperature treatment (abrupt versus gradual temperature decline) and growth conditions (e.g. photon flux density and relative humidity) that may exacerbate chilling stress. • Scope This review explores roles of B nutrition in chilling tolerance of continual root or transient shoot chills in crop species adapted to warm season conditions. It reviews current research on combined effects of chilling temperature (ranging from >0 to 20?°C) and B deficiency on growth and B nutrition responses in crop species differing in chilling tolerance. •Conclusion For subtropical/tropical species (e.g. cucumber, cassava, sunflower), root chilling at 10–17?°C decreases B uptake efficiency and B utilization in the shoot and increases the shoot : root ratio, but chilling-tolerant temperate species (e.g. oilseed rape, wheat) require much lower root chill temperatures (2–5?°C) to achieve the same responses. Boron deficiency exacerbates chilling injuries in leaf tissues, particularly under high photon flux density. Suggested mechanisms for B × chilling interactions in plants are: (a) chilling-induced reduction in plasmalemma hydraulic conductivity, membrane fluidity, water channel activity and root pressure, which contribute to the decrease in root hydraulic conductance, water uptake and associated B uptake; (b) chilling-induced stomatal dysfunction affecting B transport from root to shoot and B partitioning in the shoot; and (c) B deficiency induced sensitivity to photo-oxidative damage in leaf cells. However, specific evidence for each of the mechanisms is still lacking. Impacts of B status on chilling tolerance in crop species have important implications for the management of B supply during sensitive stages of growth, such as early growth after planting and early reproductive development, both of which can coincide with the occurrence of chilling temperatures in the field. PMID:16033777

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    E-print Network

    Byrne, Michael Patrick

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

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

    PubMed Central

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

    2014-01-01

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

  9. Effects of climate warming and species richness on photochemistry of grasslands.

    PubMed

    Gielen, Birgit; Naudts, Kim; D'Haese, David; Lemmens, Catherine M H M; De Boeck, Hans J; Biebaut, Eddy; Serneels, Roger; Valcke, Roland; Nijs, Ivan; Ceulemans, Reinhart

    2007-10-01

    In view of the projected climatic changes and the global decrease in plant species diversity, it is critical to understand the effects of elevated air temperature (T(air)) and species richness (S) on physiological processes in plant communities. Therefore, an experiment of artificially assembled grassland ecosystems, with different S (one, three or nine species), growing in sunlit climate-controlled chambers at ambient T(air) and ambient T(air) + 3 degrees C was established. We investigated whether grassland species would be more affected by midday high-temperature stress during summer in a warmer climate scenario. The effect of elevated T(air) was expected to differ with S. This was tested in the second and third experimental years by means of chlorophyll a fluorescence. Because acclimation to elevated T(air) would affect the plant's stress response, the hypothesis of photosynthetic acclimation to elevated T(air) was tested in the third year by gas exchange measurements in the monocultures. Plants in the elevated T(air) chambers suffered more from midday stress on warm summer days than those in ambient chambers. In absence of severe drought, the quantum yield of PSII was not affected by elevated T(air). Our results further indicate that species had not photosynthetically acclimated to a temperature increase of 3 degrees C after 3 years exposure to a warmer climate. Although effects of S and T(air) x S interactions were mostly not significant in our study, we expect that combined effects of T(air) and S would be important in conditions of severe drought events. PMID:18251896

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

    PubMed Central

    Schuldiner-Harpaz, Tarryn; Coll, Moshe

    2013-01-01

    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

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

    ERIC Educational Resources Information Center

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

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

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

    PubMed Central

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

    2014-01-01

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

  13. Ocean Conditions, Salmon, and Climate Change

    E-print Network

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

  14. The impact of warming climate on late summer snow cover in northwestern Finland

    NASA Astrophysics Data System (ADS)

    Kivinen, S.; Kaarlejärvi, E.; Jylhä, K.; Räisänen, J.

    2012-04-01

    Snowbeds and snow patches are characteristic features of arctic and alpine regions and are classified as endangered habitats due to the warming climate. We studied interannual variation of late summer snow cover and the factors affecting it in sub-arctic Enontekiö Lapland, northwestern Finland in years 2000, 2004, 2006, and 2009. Snow cover at 30 m resolution was derived from Landsat TM and ETM+ images obtained between 27 July and 4 August using a normalized difference snow index (NDSI). A generalized linear model (GLM) was constructed for the number (0 - 4) of snow occurrence years in 1-km grid squares. Explanatory variables in the model were elevation, terrain ruggedness, insolation and aspect. Variation in climatic conditions in the study region was examined using temperature and precipitation data from 1995 to 2009 (Finnish Meteorological Institute) and climate scenarios derived from the ENSEMBLES and PRUDENCE simulations extending to the period of 2070-2099. Late summer snow covered 23.0 km2 in 2000, 2.7 km2 in 2004, 1.5 km2 in 2006, and 5.0 km2 in 2009 of the 3176.5 km2 study area (mean altitude 727 m, maximum altitude 1310 m). The decline of snow cover was most prominent below 900 meters and on southern and western slopes. In year 2000, approximately a half of the snow cover was found above 900 meters (where 7% of the total study area is located) compared to circa 75% in 2004 and 2006, and 62% in 2009. Analyses at the 1-km resolution showed that in 19 % of the study squares there was late summer snow at least in one of the four years. Elevation and terrain ruggedness were the strongest explanatory variables for the number of snow occurrence year in a univariate GLM model. The GLM model including all variables explained 73% of the variation in the number of snow occurrence years. The interannual variation in late summer snow cover reflects the climatic variation in the study region. The mean annual temperature increased on average by 0.16°C per year during 1995-2009. Warming was most noticeable in November-December (0.37°C/year) and April- May (0.33°C/year). The number of frost days and the proportion of the snow of the total precipitation amount generally decreased during the study period. A higher number of frost days and a snowfall peak in 2008 probably explain the observed slight increase in the summer snow cover in 2009. ENSEMBLES models predict the greatest warming to take place in winter, from late autumn to early spring (ca 5.5°C by 2070-2099). Snowfall is predicted to increase 7-26% in November-March and to decrease notably in April-October. Further, PRUDENCE models predict a significant decrease in the number of frost days from average of 240 in 1961-1990 to 185 in 2071-2100. These results suggest that future climatic conditions in the study area will not support the summer occurrence of snowbeds and snow patches, which leads to threat to the alpine species and communities associated with snow and moist soils.

  15. Artificial climate warming positively affects arbuscular mycorrhizae but decreases soil aggregate water stability in an annual grassland

    Microsoft Academic Search

    Matthias C. Rillig; Sara F. Wright; M. Rebecca Shaw; Christopher B. Field

    2002-01-01

    Despite the importance of arbuscular mycorrhizae to the functioning of terrestrial ecosystems (e.g. nutrient uptake, soil aggregation), and the increasing evidence of global warming, responses of arbuscular mycorrhizal fungi (AMF) to climate warm- ing are poorly understood. In a field experiment using infrared heaters, we found effects of warming on AMF after one growing season in an annual grassland, in

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

    E-print Network

    Baez, John

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

  17. Forest plant community changes during 1989-2007 in response to climate warming in the Jura Mountains (France and Switzerland)

    E-print Network

    Bert, Didier

    of lowland species. Analyses of ecological indicator values indicated increases in temperature and lightForest plant community changes during 1989-2007 in response to climate warming in the Jura Question: How strong are climate warming-driven changes within mid-elevation forest communities

  18. Climate warming and activity period extension in the Mediterranean snake Malpolon monspessulanus

    Microsoft Academic Search

    Gregorio Moreno-Rueda; Juan M. Pleguezuelos; Esmeralda Alaminos

    2009-01-01

    Plants and animals are responding to climate warming with predictable changes in distribution and physiology. Ectothermic\\u000a animals are dependent upon environmental temperature, and their seasonal activity patterns are constrained by temperature.\\u000a Ectotherms (such as snakes) may alter their activity patterns in concordance with climatic change, and we tested this hypothesis\\u000a in a Mediterranean region (SE Spain) with the Montpellier snake

  19. Disrupted seasonal clockwork in the population dynamics of a freshwater copepod by climate warming

    Microsoft Academic Search

    Monika Winder; Daniel E. Schindler; Timothy E. Essington; Arni H. Litt

    2009-01-01

    Life history responses are expected to accompany climate warming, yet little is known how long-term effects of climate and environmental change affect the seasonal dynamics of planktonic organisms. We used an historical data set from Lake Washington (U.S.A.) to quantify population responses of a calanoid copepod (Leptodiaptomus ashlandi) to long-term changes in temperature and resource availability and explore potential mechanisms

  20. Climate Kids: It's Cold! Is Global Warming Over?

    NSDL National Science Digital Library

    The movement of Arctic air, known as the Arctic oscillation, can and will cause periodic extreme winter weather outside the Arctic region - the harsh winter experienced in many parts of the U.S. in 2010 is a recent example. This article explains the connection between the two events. This article is part of the Climate Kids website, a NASA education resource featuring articles, videos, images and games focused on the science of climate change.

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

    PubMed

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  3. Recent slowdown of tropical upper tropospheric warming associated with Pacific climate variability

    NASA Astrophysics Data System (ADS)

    Kamae, Youichi; Shiogama, Hideo; Watanabe, Masahiro; Ishii, Masayoshi; Ueda, Hiroaki; Kimoto, Masahide

    2015-04-01

    Observed upper tropospheric temperature over the tropics (TTUT) shows a slowdown in warming rate during 1997-2011 despite the continuous warming projected by coupled atmosphere-ocean general circulation models (AOGCMs). This observation-model discord is an underlying issue regarding the reliability of future climate projections based on AOGCMs. To investigate the slowdown, we conducted ensemble historical simulations using an atmospheric general circulation model (AGCM) forced by observed sea surface temperature both with and without anthropogenic influences. The historical AGCM run reproduced a muted TTUT change over the central Pacific (CP) found in multiple observations, while the multi-AOGCM mean did not. Recent tropical Pacific cooling, which is considered natural variability, contributes to the muted trend over the CP and the resultant slowdown of TTUT increase. The results of this study suggest that difficulties in simulating the recent "upper tropospheric warming hiatus" do not indicate low reliability of AOGCM-based future climate projections.

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

    EPA Science Inventory

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

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

    E-print Network

    Sukthankar, Gita Reese

    on the content and structure of their political communication. In this study, we examine political polar- izationPolitical Polarization over Global Warming: Analyzing Twitter Data on Climate Change Alireza@eecs.ucf.edu Abstract The widespread adoption of social media for political com- munication creates unprecedented

  6. Comment on ``Coral reef calcification and climate change: The effect of ocean warming''

    E-print Network

    Kleypas, Joanie

    that rising sea surface temperature will have a uniformly positive effect on coral calcification over increase with rising temperature, that increase is unlikely to continue throughout a 2­3°C rise. [3] ManyComment on ``Coral reef calcification and climate change: The effect of ocean warming'' J. A

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

    Microsoft Academic Search

    Michael R. Rampino; Tyler Volk

    1988-01-01

    The possible climatic effects of a drastic decrease in cloud condensation nuclei (CCN) associated with a severe reduction in the global marine phytoplankton abundance are investigated. Calculations suggest that a reduction in CCN of more than 80 percent and the resulting decrease in marine cloud albedo could have produced a rapid global warming of 6 C or more. Oxygen isotope

  8. Oceanic Climate Change: Contributions of Heat Content, Temperature, and Salinity Trends to Global Warming

    Microsoft Academic Search

    Christopher M. Mirabito

    The World Ocean is the largest component of the global climate system, and changes to its heat content, temperature, and salinity have an enormous impact on the current global warming trend. In this paper, these physical changes are discussed in detail, including potential sources of change and spatial and temporal variability, as the observed trends are influenced by location as

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

    E-print Network

    Harrison, Susan

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

  10. Changing forest water yields in response to climate warming: results from long-term experimental watershed

    E-print Network

    Changing forest water yields in response to climate warming: results from long-term experimental, ON N6A 5B7, Canada, 2 Department of Geography, College of Earth, Ocean, and Atmospheric Sciences Bank Drive, Peterborough, ON K9J 7B8, Canada, 4 USDA Forest Service, NRS, P.O. Box 404, Parsons, WV

  11. Response of littoral vegetation on climate warming in the boreal zone; an experimental simulation

    Microsoft Academic Search

    Paula Kankaala; Anne Ojala; Tiina Tulonen; Juha Haapamäki; Lauri Arvola

    2000-01-01

    The impact of climate warming on the littoral zone of a boreal lake ecosystem was studied experimentally for three growing seasons in two artificial ponds (10×27 m) and in replicated chamber experiments. One pond was enclosed in a plastic greenhouse and another untreated pond served as a reference system. During the growing seasons temperature in the greenhouse was maintained at levels

  12. Population decrease of Scirpophaga incertulas Walker (Lepidoptera Pyralidae) under climate warming

    PubMed Central

    Shi, Peijian; Zhong, Ling; Sandhu, Hardev S; Ge, Feng; Xu, Xiaoming; Chen, Wei

    2012-01-01

    Scirpophaga incertulas Walker is an important agricultural pest in Asia. Only few studies are available on its long-term population dynamics under climate warming. In this study, we used the linear and generalized additive models (GAMs) to analyze the historical dataset of >50 years on this pest at Xinfeng County of Jiangxi Province, China. The main objective of this study was to explore the effects of density (delayed) dependence and minimum annual temperature (MAT), which indirectly reflects climate warming, on the population dynamics of this pest. We found that both density dependence and MAT have significant influence on the annual population growth rate. The GAMs had relatively better applicability to the dataset than the linear models. Nonparametric model provided satisfactory goodness-of-fit (R2 > 0.5). At Xinfeng County, the MAT had a significant effect on the annual population growth rate of S. incertulas. The annual population growth rate of S. incertulas decreased with increase in MAT. Therefore, S. incertulas population becomes smaller and smaller in Southern China due to climate warming. The current study has two contributions: (1) providing a suitable method for predicting the annual population growth rate of S. incertulas, and (2) demonstrating that climate warming could decrease the S. incertulas population. PMID:22408726

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

    Microsoft Academic Search

    N. W. Arnell; N. S. Reynard

    1996-01-01

    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

  14. Increases in flood magnitudes in California under warming climates

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    PubMed

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

    2014-07-01

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

  17. Photosynthesis of temperate Eucalyptus globulus trees outside their native range has limited adjustment to elevated CO2 and climate warming.

    PubMed

    Crous, Kristine Y; Quentin, Audrey G; Lin, Yan-Shih; Medlyn, Belinda E; Williams, David G; Barton, Craig V M; Ellsworth, David S

    2013-12-01

    Eucalyptus species are grown widely outside of their native ranges in plantations on all vegetated continents of the world. We predicted that such a plantation species would show high potential for acclimation of photosynthetic traits across a wide range of growth conditions, including elevated [CO2] and climate warming. To test this prediction, we planted temperate Eucalyptus globulus Labill. seedlings in climate-controlled chambers in the field located >700 km closer to the equator than the nearest natural occurrence of this species. Trees were grown in a complete factorial combination of elevated CO2 concentration (eC; ambient [CO2] +240 ppm) and air warming treatments (eT; ambient +3 °C) for 15 months until they reached ca. 10 m height. There was little acclimation of photosynthetic capacity to eC and hence the CO2-induced photosynthetic enhancement was large (ca. 50%) in this treatment during summer. The warming treatment significantly increased rates of both carboxylation capacity (V(cmax)) and electron transport (Jmax) (measured at a common temperature of 25 °C) during winter, but decreased them significantly by 20-30% in summer. The photosynthetic CO2 compensation point in the absence of dark respiration (?*) was relatively less sensitive to temperature in this temperate eucalypt species than for warm-season tobacco. The temperature optima for photosynthesis and Jmax significantly changed by about 6 °C between winter and summer, but without further adjustment from early to late summer. These results suggest that there is an upper limit for the photosynthetic capacity of E. globulus ssp. globulus outside its native range to acclimate to growth temperatures above 25 °C. Limitations to temperature acclimation of photosynthesis in summer may be one factor that defines climate zones where E. globulus plantation productivity can be sustained under anticipated global environmental change. PMID:23824839

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    PubMed

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

    2010-11-01

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

  20. Climate conditions in bedded confinement buildings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Confinement buildings are utilized for finishing cattle to allow more efficient collection of animal waste and to buffer animals against adverse climatic conditions. Environmental data were obtained from a 29 m wide x 318 m long bedded confinement building with the long axis oriented east to west. T...

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

    NASA Astrophysics Data System (ADS)

    Izumi, Kenji; Bartlein, Patrick; Harrison, Sandy

    2015-04-01

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

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

    USGS Publications Warehouse

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

    2013-01-01

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

  3. Increases in Flood Magnitudes in California Under Warming Climates

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  4. Increases in flood magnitudes in California under warming climates

    USGS Publications Warehouse

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

    2013-01-01

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

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

    E-print Network

    Bershady, Matthew A.

    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

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

    PubMed

    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

    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

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-01-01

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

  10. Mapping climate conditions with materials corrosion

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    The world's first comprehensive materials corrosion mapping system can predict the effects that climatic conditions have on the life cycle of products ranging from automobiles to bridges, according to Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the Australian Industrial Galvanizers Corporation. Both jointly announced the system on 14 November.The mapping system, which incorporates conditions such as moisture, salinity pollution, and prevailing winds, can predict the corrosion of materials in any part of Australia, they said. Ivan Cole of CSIRO Materials Engineering said the mapping system even takes into account durability factors impacting on greenhouse gas contributions and soil conditions, making it a unique tool for Australian industry.

  11. Arctic sea ice response to atmospheric forcings with varying levels of anthropogenic warming and climate variability

    NASA Astrophysics Data System (ADS)

    Zhang, Jinlun; Steele, Michael; Schweiger, Axel

    2010-10-01

    Numerical experiments are conducted to project arctic sea ice responses to varying levels of future anthropogenic warming and climate variability over 2010-2050. A summer ice-free Arctic Ocean is likely by the mid-2040s if arctic surface air temperature (SAT) increases 4°C by 2050 and climate variability is similar to the past relatively warm two decades. If such a SAT increase is reduced by one-half or if a future Arctic experiences a range of SAT fluctuation similar to the past five decades, a summer ice-free Arctic Ocean would be unlikely before 2050. If SAT increases 4°C by 2050, summer ice volume decreases to very low levels (10-37% of the 1978-2009 summer mean) as early as 2025 and remains low in the following years, while summer ice extent continues to fluctuate annually. Summer ice volume may be more sensitive to warming while summer ice extent more sensitive to climate variability. The rate of annual mean ice volume decrease relaxes approaching 2050. This is because, while increasing SAT increases summer ice melt, a thinner ice cover increases winter ice growth. A thinner ice cover also results in a reduced ice export, which helps to further slow ice volume loss. Because of enhanced winter ice growth, arctic winter ice extent remains nearly stable and therefore appears to be a less sensitive climate indicator.

  12. Impact of CO2Induced Warming on Simulated Hurricane Intensity and Precipitation: Sensitivity to the Choice of Climate Model and Convective Parameterization

    Microsoft Academic Search

    Thomas R. Knutson; Robert E. Tuleya

    2004-01-01

    Previous studies have found that idealized hurricanes, simulated under warmer, high-CO 2 conditions, are more intense and have higher precipitation rates than under present-day conditions. The present study explores the sensitivity of this result to the choice of climate model used to define the CO2-warmed environment and to the choice of convective parameterization used in the nested regional model that

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

    PubMed

    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

    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

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

    USGS Publications Warehouse

    Huntington, T.G.

    2003-01-01

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

  15. Climate. Varying planetary heat sink led to global-warming slowdown and acceleration.

    PubMed

    Chen, Xianyao; Tung, Ka-Kit

    2014-08-22

    A vacillating global heat sink at intermediate ocean depths is associated with different climate regimes of surface warming under anthropogenic forcing: The latter part of the 20th century saw rapid global warming as more heat stayed near the surface. In the 21st century, surface warming slowed as more heat moved into deeper oceans. In situ and reanalyzed data are used to trace the pathways of ocean heat uptake. In addition to the shallow La Niña-like patterns in the Pacific that were the previous focus, we found that the slowdown is mainly caused by heat transported to deeper layers in the Atlantic and the Southern oceans, initiated by a recurrent salinity anomaly in the subpolar North Atlantic. Cooling periods associated with the latter deeper heat-sequestration mechanism historically lasted 20 to 35 years. PMID:25146282

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

    PubMed

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

    2010-12-23

    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

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

    NASA Technical Reports Server (NTRS)

    Hameed, S.; Cess, R. D.

    1980-01-01

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

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

    PubMed Central

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

    2010-01-01

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

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

    PubMed Central

    Yi, Chuixiang; Wei, Suhua; Hendrey, George

    2014-01-01

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

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

    PubMed

    Yi, Chuixiang; Wei, Suhua; Hendrey, George

    2014-01-01

    At biome-scale, terrestrial carbon uptake is controlled mainly by weather variability. Observational data from a global monitoring network indicate that the sensitivity of terrestrial carbon sequestration to mean annual temperature (T) breaks down at a threshold value of 16°C, above which terrestrial 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

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

    Microsoft Academic Search

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

    1990-01-01

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

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

    Microsoft Academic Search

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

    2011-01-01

    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

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

    Microsoft Academic Search

    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

    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

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

    Microsoft Academic Search

    Stefan Rahmstorf; Andrey Ganopolski

    1999-01-01

    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

  5. 500-year climate cycles stacking of recent centennial warming documented in an East Asian pollen record.

    PubMed

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

    2014-01-01

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

  6. 500-year climate cycles stacking of recent centennial warming documented in an East Asian pollen record

    PubMed Central

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

    2014-01-01

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

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

    E-print Network

    Rose, Brian E. J.

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

  8. Elevation-dependent responses of streamflow to climate warming Christopher J. Tennant,* Benjamin T. Crosby and Sarah E. Godsey

    E-print Network

    Crosby, Benjamin T.

    Elevation-dependent responses of streamflow to climate warming Christopher J. Tennant,* Benjamin T, Pocatello, ID, 83209-8072, USA Abstract: Warming will affect snowline elevation, potentially altering elevation-dependent responses is difficult because many gauged watersheds integrate drainage areas

  9. Relative Contributions of Global Warming to Various Climate Sensitive Risks, and Their Implications for Adaptation and Mitigation

    Microsoft Academic Search

    Indur M. Goklany

    2003-01-01

    A rationale for mitigating global warming (GW) is that warming might exacerbate many of today's urgent problems — hunger, malaria, water shortage, coastal flooding, and habitat conversion — which could be particularly problematic for developing countries. Recent assessments of the global impacts of climate change indicate that into the 2080s, except for coastal flooding, GW's contribution to these problems (?P(GW))

  10. Phytoplankton response to climate warming modified by trophic state

    Microsoft Academic Search

    Veronika Huber; Rita Adrian; Dieter Gerten

    Abstract We investigated the combined,effect of reduced phosphorus,supply and warmer winter and,spring conditions on the diatom,spring bloom,of a shallow lake. Simulations with a simple dynamic model,indicated that reduced ice cover and,increasing water temperatures,resulted in a more,intense and,earlier bloom,independently,of phosphorous concentrations. However, whereas the collapse of the bloom was caused by silicate limitation under high phosphorus supply, it was caused by

  11. Global and regional cooling in a warming climate from CMIP5 models

    NASA Astrophysics Data System (ADS)

    Medhaug, Iselin; Drange, Helge

    2015-04-01

    Instrumental temperature records show that the global climate may experience decadal-scale (hiatus) periods without warming despite an indisputable long-term warming trend. A large range of factors have been proposed to explain these non-warming decades, like volcanic cooling, reduced solar energy input, low stratospheric water vapor content, elevated tropospheric aerosols, internal variability of the climate system, or a combination thereof. We have analysed 17 global climate models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5), identifying the likelihood and duration of periods without warming in the four Representative Concentration Pathway (RCP) scenarios RCP2.6, RCP4.5, RCP6.0 and RCP8.5, together with the preindustrial control and historical simulations. We find that non-warming periods, when the effect of volcanic eruptions and variations in the solar cycle are neglected, may last for up to 10, 15 and 30 years for RCP8.5, RCP6.0 and RCP 4.5, respectively. Regionally, the likelihood of a decadal-scale hiatus periods decrease first in the tropical Atlantic, Indian Ocean and western Pacific with increasing global temperatures in the RCP scenarios. The North Atlantic and the Southern Ocean are the regions with largest variability relative to the regional warming signal. As a response to the global temperature increase, the radiative imbalance at top of the atmosphere increases and the global oceans warm. This holds for both the upper and the deep ocean in all scenarios. In the CMIP5 simulations, anomalous uptake and storage of ocean heat are the main factors explaining the decadal-scale surface temperature hiatus periods. The tropical East Pacific is a key region for these variations, acting in tandem with basin-scale anomalies in the sea level pressure. On sub-decadal time scales, ocean storage of heat is largest and comparable in magnitude in the Pacific and Southern Oceans, followed by the Atlantic Ocean. We find no relation between the decadal-scale hiatus periods and the decadal net top of atmosphere radiation variability.

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

    PubMed

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

    2014-11-01

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

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

    PubMed

    Springate, David A; Kover, Paula X

    2014-02-01

    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

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

    PubMed Central

    Springate, David A; Kover, Paula X

    2014-01-01

    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

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

    E-print Network

    Paris-Sud XI, Université de

    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

  16. 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

    Paris-Sud XI, Université de

    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

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

    PubMed Central

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

    2014-01-01

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

  18. Food benefit and climate warming potential of nitrogen fertilizer uses in China

    NASA Astrophysics Data System (ADS)

    Tian, Hanqin; Lu, Chaoqun; Melillo, Jerry; Ren, Wei; Huang, Yao; Xu, Xiaofeng; Liu, Mingliang; Zhang, Chi; Chen, Guangsheng; Pan, Shufen; Liu, Jiyuan; Reilly, John

    2012-12-01

    Chemical nitrogen (N) fertilizer has long been used to help meet the increasing food demands in China, the top N fertilizer consumer in the world. Growing concerns have been raised on the impacts of N fertilizer uses on food security and climate change, which is lack of quantification. Here we use a carbon-nitrogen (C-N) coupled ecosystem model, to quantify the food benefit and climate consequence of agronomic N addition in China over the six decades from 1949 to 2008. Results show that N fertilizer-induced crop yield and soil C sequestration had reached their peaks, while nitrous oxide (N2O) emission continued rising as N was added. Since the early 2000s, stimulation of excessive N fertilizer uses to global climate warming through N2O emission was estimated to outweigh their climate benefit in increasing CO2 uptake. The net warming effect of N fertilizer uses, mainly centered in the North China Plain and the middle and lower reaches of Yangtze River Basin, with N2O emission completely counteracting or even exceeding, by more than a factor of 2, the CO2 sink. If we reduced the current N fertilizer level by 60% in ‘over-fertilized’ areas, N2O emission would substantially decrease without significantly influencing crop yield and soil C sequestration.

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

    SciTech Connect

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

    2010-01-01

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

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

    USGS Publications Warehouse

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

    2009-01-01

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

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

    PubMed

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

    2015-06-22

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    This study examines future changes of cold air outbreaks (CAOs) using a multi-model ensemble of global climate simulations from the Coupled Model Intercomparison Project Phase 5 and high resolution regional climate simulations. Overall, climate models agree on a dip in CAO duration across North America, but the percentage change is consistently smaller from western Canada to the upper mid-western US with historically more frequent CAO. By decomposing the changes of the probability density function of daily surface temperature into changes due to mean warming and changes in standard deviation (std) and skewness/higher order moments, the contributions of each factor to CAO changes are quantified. Results show that CAO changes can be explained largely by the mean warming, but the decrease in temperature std contributes to about 20% reduction of CAO from Alaska to northeastern US and eastern Canada possibly due to the Arctic amplification and weakening of storm track. A thermodynamical modulation of the skewness called the ‘0 °C mode’ effect is found to operate prominently along the 0 °C isotherm hemispherically and reduce CAO in western and northeastern US with winter snow cover by up to 10%. This effect also produces a manifold increase in CAO events over the Arctic sea ice. An increased frequency in atmospheric blocking also contributes to increases in CAO duration over Alaska and the Arctic region. Regional simulations revealed more contributions of existing snowpack to CAO in the near future over the Rocky Mountain, southwestern US, and Great Lakes areas through surface albedo effects. Overall, the multi-model projections emphasize that cold extremes do not completely disappear in a warming climate. Concomitant with the relatively smaller reduction in CAO events in northwestern US, the top five most extreme CAO events may still occur, and wind chill will continue to have societal impacts in that region.

  4. Supraglacial lakes on the Greenland ice sheet advance inland under warming climate

    NASA Astrophysics Data System (ADS)

    Leeson, A. A.; Shepherd, A.; Briggs, K.; Howat, I.; Fettweis, X.; Morlighem, M.; Rignot, E.

    2015-01-01

    Supraglacial lakes (SGLs) form annually on the Greenland ice sheet and, when they drain, their discharge enhances ice-sheet flow by lubricating the base and potentially by warming the ice. Today, SGLs tend to form within the ablation zone, where enhanced lubrication is offset by efficient subglacial drainage. However, it is not clear what impact a warming climate will have on this arrangement. Here, we use an SGL initiation and growth model to show that lakes form at higher altitudes as temperatures rise, consistent with satellite observations. Our simulations show that in southwest Greenland, SGLs spread 103 and 110 km further inland by the year 2060 under moderate (RCP 4.5) and extreme (RCP 8.5) climate change scenarios, respectively, leading to an estimated 48-53% increase in the area over which they are distributed across the ice sheet as a whole. Up to half of these new lakes may be large enough to drain, potentially delivering water and heat to the ice-sheet base in regions where subglacial drainage is inefficient. In such places, ice flow responds positively to increases in surface water delivered to the bed through enhanced basal lubrication and warming of the ice, and so the inland advance of SGLs should be considered in projections of ice-sheet change.

  5. Supraglacial lakes advance inland on the Greenland ice sheet under warming climate

    NASA Astrophysics Data System (ADS)

    Leeson, Amber; Shepherd, Andrew; Briggs, Kate; Howat, Ian; Fettweis, Xavier; Morlighem, Mathieu; Rignot, Eric

    2015-04-01

    Supraglacial lakes (SGLs) form annually on the Greenland ice sheet and, when they drain, their discharge enhances ice-sheet flow by lubricating the base and potentially by warming the ice. Today, SGLs tend to form within the ablation zone,where enhanced lubrication is offset by effcient subglacial drainage. However, it is not clear what impact a warming climate will have on this arrangement. Here, we use an SGL initiation and growth model to show that lakes form at higher altitudes as temperatures rise, consistent with satellite observations of their distribution in cooler times. Our simulations show that in southwest Greenland, SGLs spread 103 to 110 km further inland by the year 2060 under moderate (RCP 4.5) and extreme (RCP 8.5) climate change scenarios, respectively, leading to an estimated 48-53% increase in the area over which they are distributed across the ice sheet as a whole. Up to half of these new lakes may be large enough to drain, potentially delivering water and heat to the ice-sheet base in regions where subglacial drainage is inefficient. In such places, ice flow responds positively to increases in surface water delivered to the bed through enhanced basal lubrication and warming of the ice which suggests that projections of the ice-sheet dynamical imbalance should be revised to account for this expected evolution in SGL distribution.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    PubMed

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

    2014-09-15

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

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

    ERIC Educational Resources Information Center

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

    2015-01-01

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

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

    E-print Network

    Yin, Fan 1990-

    2012-10-26

    ) and off-site Plant Mixed Laboratory Compacted (PMLC) specimens were selected, and their effects on mixture properties were evaluated. Mixture stiffness evaluated in a dry condition using the Resilient Modulus (MR) test (ASTM D-7369) was the main parameter...

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

    NASA Astrophysics Data System (ADS)

    Rypdal, M.; Rypdal, K.

    2013-12-01

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

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

    PubMed

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

    2015-06-26

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

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

    NASA Technical Reports Server (NTRS)

    Rampino, Michael R.; Volk, Tyler

    1988-01-01

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

  13. Climate Warming May Facilitate Invasion of the Exotic Shrub Lantana camara

    PubMed Central

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

    2014-01-01

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

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

    USGS Publications Warehouse

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

    2014-01-01

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

  15. The influence of convection parameterisations under alternate climate conditions

    NASA Astrophysics Data System (ADS)

    Rybka, Harald; Tost, Holger

    2013-04-01

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

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

    Microsoft Academic Search

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

    2009-01-01

    Pliocene sea surface temperature data, as well as terrestrial precipitation and temperature proxies, indicate warmer than modern conditions in the eastern equatorial Pacific and imply permanent El Niño-like conditions with impacts similar to those of the 1997\\/1998 El Niño event. Here we use a general circulation model to examine the global-scale effects that result from imposing warm tropical sea surface

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

    Microsoft Academic Search

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

    2009-01-01

    Pliocene sea surface temperature data, as well as terrestrial precipitation and temperature proxies, indicate warmer than modern conditions in the eastern equatorial Pacific and imply permanent El Niño–like conditions with impacts similar to those of the 1997\\/1998 El Niño event. Here we use a general circulation model to examine the global-scale effects that result from imposing warm tropical sea surface

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

    PubMed

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

    2008-05-27

    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

  19. 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.

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

    NASA Astrophysics Data System (ADS)

    Schmidt, G. A.

    2006-12-01

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

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

    PubMed

    Sorte, Cascade J B; White, J Wilson

    2013-07-01

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

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

    PubMed Central

    Sorte, Cascade J. B.; White, J. Wilson

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  4. Results of roof pond heating experiments using the Passive Test Facility for warm, humid climates

    NASA Astrophysics Data System (ADS)

    Loxsom, F. M.; Olivares, P.; Kelly, B.; Clark, E.; Doderer, E.; Hayes, P.

    1981-09-01

    Passive cooling and heating methods in warm, humid climates were tested. During the winter of 1980-1981, heating experiments were carried out for roof pond systems. These experiments included: roof pond heating with glazed and unglazed water bags, heating roof ponds from below by using reflective blinds in south facing windows, and direct gain heating with the roof pond used as storage. The data for these experiments are in the form of 5 minute data for 160 sensors. Most of the sensors are thermocouples or heat flux meters. The data are stored on computer type in the form of 28 different data files for 28 different experiment periods.

  5. Climate Effect of Greenhouse Gas: Warming or Cooling is Determined by Temperature Gradient

    NASA Astrophysics Data System (ADS)

    Shia, R.

    2011-12-01

    The instantaneous radiative forcing (IRF) at the top of the atmosphere (ToA) is the initial change of the total energy in the climate system when the concentration of greenhouse gas (GHG) increases. In my previous presentation at the 2010 Fall AGU meeting (A11J-02, "Mechanism of Radiative Forcing of Greenhouse Gas its Implication to the Global Warming"), it was demonstrated that IRF at TOA is generated by moving up of the emission weighting function. Thus, the temperature gradient plays a critical role in determining the climate effect of GHG. In this presentation the change of the outgoing infrared radiation flux at ToA is studied from a perturbation point of view. After the cancellation between the changes in the outgoing radiation flux from the surface emission and from the reemission of the atmosphere, the derivative of the outgoing flux to the concentration of GHG is found to be proportional to the temperature gradients below the level where the concentration of GHG changes. Therefore, the greenhouse gas contribute only to the magnitude of the radiative forcing, the temperature gradients decide the direction of the radiative forcing, i.e. warming or cooling, in addition to contributing to its magnitude. In response to the question "Does the negative IRF at ToA lead to the surface cooling or it only cools the upper part of the atmosphere?" the Eddington grey radiative equilibrium model is modified to simulate different scenarios. The original model has been used to illustrate the warming effect of GHG in textbooks of the atmospheric physics. It is modified by adding source terms from the absorption of the solar flux and the internal energy exchange in the atmosphere. In two cases the modified model generates atmospheres with a large and warm stratosphere and negative IRF at ToA when GHG increases by 25%. This negative radiative forcing can lead to the cooling of the atmosphere all the way down to the surface. The implications of the cooling effect of GHG to the climate change, including paleoclimatology and the prerequests for climate models to include cooling effect of GHG properly are discussed.

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

    PubMed Central

    Koneswaran, Gowri; Nierenberg, Danielle

    2008-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Budikova, D.; Chechi, L.

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Kang, Nam-Young

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

  14. Initialized Decadal Climate Predictions of the Observed Early-2000s Hiatus of Global Warming

    NASA Astrophysics Data System (ADS)

    Meehl, G. A.; Teng, H.; Arblaster, J.

    2014-12-01

    The slow-down 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 CMIP5 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 prior to the mid-1990s points to the need for consistent hindcast skill to establish reliability of an operational decadal climate prediction system.

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

    PubMed

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

    2013-10-01

    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

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

    PubMed

    Bell-Scriber, Marietta J

    2008-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  19. Climate warming during Antarctic ice sheet expansion at the Middle Miocene transition

    NASA Astrophysics Data System (ADS)

    Knorr, Gregor; Lohmann, Gerrit

    2014-05-01

    During the Middle Miocene climate transition about 14 million years ago, the Antarctic ice sheet expanded to near-modern volume. Surprisingly, this ice sheet growth was accompanied by a warming in the surface waters of the Southern Ocean, whereas a slight deep-water temperature increase was delayed by more than 200 thousand years. Here we use a coupled atmosphere-ocean model to assess the relative effects of changes in atmospheric CO2 concentration and ice sheet growth on regional and global temperatures. In the simulations, changes in the wind field associated with the growth of the ice sheet induce changes in ocean circulation, deep-water formation and sea-ice cover that result in sea surface warming and deep-water cooling in large swaths of the Atlantic and Indian ocean sectors of the Southern Ocean. We interpret these changes as the dominant ocean surface response to a 100-thousand-year phase of massive ice growth in Antarctica. A rise in global annual mean temperatures is also seen in response to increased Antarctic ice surface elevation. In contrast, the longer-term surface and deep-water temperature trends are dominated by changes in atmospheric CO2 concentration. We therefore conclude that the climatic and oceanographic impacts of the Miocene expansion of the Antarctic ice sheet are governed by a complex interplay between wind field, ocean circulation and the sea-ice system.

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

    PubMed

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

    2007-10-01

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

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

    PubMed Central

    Roth, Tobias; Plattner, Matthias; Amrhein, Valentin

    2014-01-01

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

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

    Microsoft Academic Search

    S. Fischer; J. Sand; V. Baxter

    1997-01-01

    International agreements mandate the phase-out of many chlorine containing compounds that are used as the working fluid in refrigeration, air-conditioning, and heating equipment. Many of the chemical compounds that have been proposed, and are being used in place of the class of refrigerants eliminated by the Montreal Protocol are now being questioned because of their possible contributions to global warming.

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

    Microsoft Academic Search

    G. Palumbo; D. Sorgente; L. Tricarico

    2009-01-01

    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

  4. Decreased frequency of North Atlantic polar lows associated with future climate warming.

    PubMed

    Zahn, Matthias; von Storch, Hans

    2010-09-16

    Every winter, the high-latitude oceans are struck by severe storms that are considerably smaller than the weather-dominating synoptic depressions. Accompanied by strong winds and heavy precipitation, these often explosively developing mesoscale cyclones-termed polar lows-constitute a threat to offshore activities such as shipping or oil and gas exploitation. Yet owing to their small scale, polar lows are poorly represented in the observational and global reanalysis data often used for climatological investigations of atmospheric features and cannot be assessed in coarse-resolution global simulations of possible future climates. Here we show that in a future anthropogenically warmed climate, the frequency of polar lows is projected to decline. We used a series of regional climate model simulations to downscale a set of global climate change scenarios from the Intergovernmental Panel of Climate Change. In this process, we first simulated the formation of polar low systems in the North Atlantic and then counted the individual cases. A previous study using NCEP/NCAR re-analysis data revealed that polar low frequency from 1948 to 2005 did not systematically change. Now, in projections for the end of the twenty-first century, we found a significantly lower number of polar lows and a northward shift of their mean genesis region in response to elevated atmospheric greenhouse gas concentration. This change can be related to changes in the North Atlantic sea surface temperature and mid-troposphere temperature; the latter is found to rise faster than the former so that the resulting stability is increased, hindering the formation or intensification of polar lows. Our results provide a rare example of a climate change effect in which a type of extreme weather is likely to decrease, rather than increase. PMID:20844533

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  6. Comparison of Shoulder Range of Motion, Strength, and Playing Time in Uninjured High School Baseball Pitchers Who Reside in Warm and Cold-Weather Climates

    Microsoft Academic Search

    Kevin M. Kaplan; Neal S. ElAttrache; Frank W. Jobe; Bernard F. Morrey; Kenton R. Kaufman; Wendy J. Hurd

    2011-01-01

    Background: There is an assumption that baseball athletes who reside in warm-weather climates experience larger magnitude adaptations in throwing shoulder motion and strength compared with their peers who reside in cold-weather climates.Hypotheses: (1) The warm-weather climate (WWC) group would exhibit more pronounced shoulder motion and strength adaptations than the cold-weather climate (CWC) group, and (2) the WWC group would participate

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

    Microsoft Academic Search

    J. R. Sand; S. K. Fischer

    1997-01-01

    The Montreal Protocol phase-out of chlorofluorocarbons (CFCs) has required manufacturers to develop refrigeration and air-conditioning systems that use refrigerants that can not damage stratospheric ozone. Most refrigeration industries have adapted their designs to use hydrochlorofluorocarbon (HCFC) or hydrofluorocarbon (HFC) refrigerants; new automobile air- conditioning systems use HFC-134a. These industries are now being affected by scientific investigations of greenhouse warming and

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

    Microsoft Academic Search

    Pasquale Cavaliere

    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

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

    SciTech Connect

    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

    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.

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

    Microsoft Academic Search

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

    2011-01-01

    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

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

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

    E-print Network

    McCune, Bruce

    National Park; Global warming; Peripheral population; Migration; Montana; Tundra. Nomenclature: Lesica- Decline of arctic-alpine plants following a decade of climatic warming - 679 Journal and the northern migration of floras. Our results also suggest that species responded to the decade of warming

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

    E-print Network

    Browning, B. K.

    2002-01-01

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

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

    DOE PAGESBeta

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

    2015-04-01

    This study examines future changes of cold air outbreaks (CAO) using a multi-model ensemble of global climate simulations from the Coupled Model Intercomparison Project Phase 5 as well as regional high resolution climate simulations. In the future, while robust decrease of CAO duration dominates in most regions, the magnitude of decrease over northwestern U.S. is much smaller than the surrounding regions. We identified statistically significant increases in sea level pressure during CAO events centering over Yukon, Alaska, and Gulf of Alaska that advects continental cold air to northwestern U.S., leading to blocking and CAO events. Changes in large scale circulation contribute to about 50% of the enhanced sea level pressure anomaly conducive to CAO in northwestern U.S. in the future. High resolution regional simulations revealed potential contributions of increased existing snowpack to increased CAO in the near future over the Rocky Mountain, southwestern U.S., and Great Lakes areas through surface albedo effects, despite winter mean snow water equivalent decreases in the future. Overall, the multi-model projections emphasize that cold extremes do not completely disappear in a warming climate. Concomitant with the relatively smaller reduction in CAO events in northwestern U.S., the top 5 most extreme CAO events may still occur in the future, and wind chill warning will continue to have societal impacts in that region.

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

    DOE PAGESBeta

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

    2015-04-01

    This study examines future changes of cold air outbreaks (CAO) using a multi-model ensemble of global climate simulations from the Coupled Model Intercomparison Project Phase 5 as well as regional high resolution climate simulations. In the future, while robust decrease of CAO duration dominates in most regions, the magnitude of decrease over northwestern U.S. is much smaller than the surrounding regions. We identified statistically significant increases in sea level pressure during CAO events centering over Yukon, Alaska, and Gulf of Alaska that advects continental cold air to northwestern U.S., leading to blocking and CAO events. Changes in large scale circulationmore »contribute to about 50% of the enhanced sea level pressure anomaly conducive to CAO in northwestern U.S. in the future. High resolution regional simulations revealed potential contributions of increased existing snowpack to increased CAO in the near future over the Rocky Mountain, southwestern U.S., and Great Lakes areas through surface albedo effects, despite winter mean snow water equivalent decreases in the future. Overall, the multi-model projections emphasize that cold extremes do not completely disappear in a warming climate. Concomitant with the relatively smaller reduction in CAO events in northwestern U.S., the top 5 most extreme CAO events may still occur in the future, and wind chill warning will continue to have societal impacts in that region.« less

  16. Stable climate and surface mass balance in Svalbard over 1979-2013 despite the Arctic warming

    NASA Astrophysics Data System (ADS)

    Lang, C.; Fettweis, X.; Erpicum, M.

    2015-01-01

    With the help of the regional climate model MAR (Modèle Atmosphérique Régional) forced by the ERA-Interim reanalysis (MARERA) and the MIROC5 (Model for Interdisciplinary Research on Climate) global model (MARMIROC5) from the CMIP5 (Coupled Model Intercomparison Project) database, we have modelled the climate and surface mass balance of Svalbard at a 10 km resolution over 1979-2013. The integrated total surface mass balance (SMB) over Svalbard modelled by MARERA is negative (-1.6 Gt yr-1) with a large interannual variability (7.1 Gt) but, unlike over Greenland, there has been no acceleration of the surface melt over the past 35 years because of the recent change in atmospheric circulation bringing northwesterly flows in summer over Svalbard, contrasting the recent observed Arctic warming. However, in 2013, the atmospheric circulation changed to a south-southwesterly flow over Svalbard causing record melt, SMB (-20.4 Gt yr-1) and summer temperature. MIROC5 is significantly colder than ERA-Interim over 1980-2005 but MARMIROC5 is able to improve the near-surface MIROC5 results by simulating not significant SMB differences with MARERA over 1980-2005. On the other hand, MIROC5 does not represent the recent atmospheric circulation shift in summer and induces in MARMIROC5 a significant trend of decreasing SMB (-0.6 Gt yr-2) over 1980-2005.

  17. Climatic conditions cause complex patterns of covariation between demographic traits in a long-lived raptor.

    PubMed

    Herfindal, Ivar; van de Pol, Martijn; Nielsen, Jan T; Saether, Bernt-Erik; Møller, Anders P

    2014-11-17

    Environmental variation can induce life-history changes that can last over a large part of the lifetime of an organism. If multiple demographic traits are affected, expected changes in climate may influence environmental covariances among traits in a complex manner. Thus, examining the consequences of environmental fluctuations requires that individual information at multiple life stages is available, which is particularly challenging in long-lived species. Here, we analyse how variation in climatic conditions occurring in the year of hatching of female goshawks Accipiter gentilis (L.) affects age-specific variation in demographic traits and lifetime reproductive success (LRS). LRS decreased with increasing temperature in April in the year of hatching, due to lower breeding frequency and shorter reproductive life span. In contrast, the probability for a female to successfully breed was higher in years with a warm April, but lower LRS of the offspring in these years generated a negative covariance among fecundity rates among generations. The mechanism by which climatic conditions generated cohort effects was likely through influencing the quality of the breeding segment of the population in a given year, as the proportion of pigeons in the diet during the breeding period was positively related to annual and LRS, and the diet of adult females that hatched in warm years contained fewer pigeons. Climatic conditions experienced during different stages of individual life histories caused complex patterns of environmental covariance among demographic traits even across generations. Such environmental covariances may either buffer or amplify impacts of climate change on population growth, emphasizing the importance of considering demographic changes during the complete life history of individuals when predicting the effect of climatic change on population dynamics of long-lived species. PMID:25403010

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    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.

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

    Microsoft Academic Search

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

    2007-01-01

    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

  20. 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

    Qin Leng; Gaytha A. Langlois; Hong Yang

    2010-01-01

    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

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

    NASA Astrophysics Data System (ADS)

    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

    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

  2. The role of climate change and ozone recovery for the future timing of major stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Ayarzagüena, Blanca; Langematz, Ulrike; Meul, Stefanie; OberläNder, Sophie; Abalichin, Janna; Kubin, Anne

    2013-05-01

    Future changes in the occurrence rates of major stratospheric warmings (MSWs) have recently been identified in chemistry-climate model (CCM) simulations, but without reaching a consensus, potentially due to the competition of different forcings. We examine future variations in the occurrence rates of MSWs in transient and timeslice simulations of the ECHAM/MESSy atmospheric chemistry (EMAC) CCM, with a focus on the individual effect of different external factors. Although no statistically significant variation is found in the decadal-mean frequency of MSWs, a shift of their timing toward midwinter is detected in the future. The strengthening of the polar vortex in early winter is explained by recovering ozone levels following the future decrease in ozone-depleting substances. In midwinter, a stronger dynamical forcing associated with changes in tropical sea surface temperatures will lead to more MSWs, through a similar mechanism that explains the stratospheric response to El Niño-Southern Oscillation (ENSO).

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  5. Effects of environmental temperature change on mercury absorption in aquatic organisms with respect to climate warming.

    PubMed

    Pack, Eun Chul; Lee, Seung Ha; Kim, Chun Huem; Lim, Chae Hee; Sung, Dea Gwan; Kim, Mee Hye; Park, Ki Hwan; Lim, Kyung Min; Choi, Dal Woong; Kim, Suhng Wook

    2014-01-01

    Because of global warming, the quantity of naturally generated mercury (Hg) will increase, subsequently methylation of Hg existing in seawater may be enhanced, and the content of metal in marine products rise which consequently results in harm to human health. Studies of the effects of temperatures on Hg absorption have not been adequate. In this study, in order to observe the effects of temperature changes on Hg absorption, inorganic Hg or methylmercury (MeHg) was added to water tanks containing loaches. Loach survival rates decreased with rising temperatures, duration, and exposure concentrations in individuals exposed to inorganic Hg and MeHg. The MeHg-treated group died sooner than the inorganic Hg-exposed group. The total Hg and MeHg content significantly increased with temperature and time in both metal-exposed groups. The MeHg-treated group had higher metal absorption rates than inorganic Hg-treated loaches. The correlation coefficients for temperature elevation and absorption were significant in both groups. The results of this study may be used as basic data for assessing in vivo hazards from environmental changes such as climate warming. PMID:25343296

  6. Differential effects of past climate warming on mountain and flatland species distributions: a multispecies North American mammal assessment

    Microsoft Academic Search

    Robert Guralnick

    2006-01-01

    Aim The magnitude of predicted range shifts during climate change is likely to be different for species living in mountainous environments compared with those living in flatland environments. The southern edges of ranges in mountain species may not shift northwards during warming as populations instead migrate up available elevational gradients; overall latitudinal range appears therefore to expand. In contrast, flatland

  7. A comprehensive review of key climate indicators confirms the world is warming and the past decade was

    E-print Network

    decades. A warmer climate means higher sea level, humidity and temperatures in the air and ocean. A warmer Humidity Ocean Heat Content Land Surface Air Temperature Over Land Temperature Over Oceans Sea expands as it warms, ocean heating is responsible for much of the sea-level rise we've observed. Melting

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

    E-print Network

    Bieber, Michael

    The dynamics of the Earth's climate and the global- warming debate are complex, to say the least determined from measurements of earthshine -- light from the Earth reflected to the dark portion of the Moon's disk and back to Earth -- that our planet has been reflecting more light back into space over the last

  9. Climate sensitivity under present and Late Cretaceous background conditions

    NASA Astrophysics Data System (ADS)

    Lohmann, Gerrit; Niezgodzki, Igor; Knorr, Gregor; Tyszka, Jaroslaw; Markwick, Paul

    2015-04-01

    We investigate the impact of different levels of CO2 for the Late Cretaceous and present configuration. For identical preindustrial CO2 concentrations (278 ppm), we find that the Cretaceous shows a more zonal and warmer climate at low latitudes relative to the present day configuration, which can be partly attributed to enhanced drying and warming in the subtropics. When changing the CO2 levels (4x278 ppm), temperature changes are most pronounced at high latitudes, especially for the respective winter season. The low-latitude response for quadrupling the CO2 level is about +9°C for both the Late Cretaceous and present configuration, with a stronger warming over land than over sea. At high latitudes, the present background climate shows a higher sensitivity relative to the changes in the Late Cretaceous configuration, caused by a colder climate background with more sea ice in the present configuration. Finally, we discuss the climate under a 6x280 ppm for the Late Cretaceous with a year-round ice-free Arctic Ocean and annual mean values of 15°C north of 60°N.

  10. Characterisation of AZ31B magnesium alloy formability in warm forming conditions

    Microsoft Academic Search

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

    2008-01-01

    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

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

    Microsoft Academic Search

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

    2006-01-01

    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

  12. Using climate model experiments to explore difference between degrees of global warming: lessons from a study of African precipitation

    NASA Astrophysics Data System (ADS)

    James, Rachel; Washington, Richard

    2015-04-01

    A 2°C increase in global mean temperature (?Tg) has been widely adopted as a benchmark for dangerous climate change, and is currently being reviewed under the United Nations Framework Convention on Climate Change. However, there has been relatively little research into the implications of 2°C, or any other degree of global warming, for regional climate. This lack of research is particularly pressing in the case of vulnerable regions, including many in Africa. In recognition of this research gap, we conducted an in depth study of changes in African temperature and precipitation associated with 1°C, 1.5°C, 2°C, 3°C, 4°C, and beyond, using output from almost 400 climate model experiments: simulations from international modelling centres (CMIP3 and CMIP5), two perturbed physics ensembles, and a group of five regional models. The implications of global warming are different depending on which models are consulted, but each model consistently shows that temperature and precipitation anomalies are enhanced progressively with global warming. At 1°C, there is little significant change, but from 1.5°C or 2°C anomalies develop which grow in magnitude and spatial extent with global temperature, for example drying over Angola, and wetting in East Africa. The main difference between ?Tg intervals is in the magnitude and spatial extent of change. There do not appear to be rapid accelerations in the rate of change or trend reversals. This is not only true for lower levels of anthropogenic forcing, but also at higher degrees of warming up to 6°C. This finding has potential implications for policy. Given that larger changes in climate are likely to generate greater challenges for society, it suggests that global temperature should be limited to the lowest level possible. It does not imply that 2°C, or any other ?Tg increment, should be a preferred target from the perspective of regional climate. However, it is important to consider whether the approximately linear relationship between global warming and local climate change implied by the model experiments is reliable. It may be that the models are unable simulate feedbacks in the earth system which might lead to nonlinear change, due to their resolution and complexity. Analysis of earth system models run in long experiments with high levels of greenhouse gas forcing does reveal some nonlinear change. Further research might be needed to test the rate of change in global climate models before their results are used to infer difference between 1.5°C, 2°C, and other degrees of warming.

  13. Darcy’s law predicts widespread forest mortality under climate warming

    USGS Publications Warehouse

    McDowell, Nate G.; Allen, Craig D.

    2015-01-01

    Drought and heat-induced tree mortality is accelerating in many forest biomes as a consequence of a warming climate, resulting in a threat to global forests unlike any in recorded history1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12. Forests store the majority of terrestrial carbon, thus their loss may have significant and sustained impacts on the global carbon cycle11,12. We use a hydraulic corollary to Darcy’s law, a core principle of vascular plant physiology13, to predict characteristics of plants that will survive and die during drought under warmer future climates. Plants that are tall with isohydric stomatal regulation, low hydraulic conductance, and high leaf area are most likely to die from future drought stress. Thus, tall trees of old-growth forests are at the greatest risk of loss, which has ominous implications for terrestrial carbon storage. This application of Darcy’s law indicates today’s forests generally should be replaced by shorter and more xeric plants, owing to future warmer droughts and associated wildfires and pest attacks. The Darcy’s corollary also provides a simple, robust framework for informing forest management interventions needed to promote the survival of current forests. Given the robustness of Darcy’s law for predictions of vascular plant function, we conclude with high certainty that today’s forests are going to be subject to continued increases in mortality rates that will result in substantial reorganization of their structure and carbon storage.

  14. Strong atmospheric chemistry feedback to climate warming from Arctic methane emissions

    USGS Publications Warehouse

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

    2011-01-01

    The magnitude and feedbacks of future methane release from the Arctic region are unknown. Despite limited documentation of potential future releases associated with thawing permafrost and degassing methane hydrates, the large potential for future methane releases calls for improved understanding of the interaction of a changing climate with processes in the Arctic and chemical feedbacks in the atmosphere. Here we apply a “state of the art” atmospheric chemistry transport model to show that large emissions of CH4 would likely have an unexpectedly large impact on the chemical composition of the atmosphere and on radiative forcing (RF). The indirect contribution to RF of additional methane emission is particularly important. It is shown that if global methane emissions were to increase by factors of 2.5 and 5.2 above current emissions, the indirect contributions to RF would be about 250% and 400%, respectively, of the RF that can be attributed to directly emitted methane alone. Assuming several hypothetical scenarios of CH4 release associated with permafrost thaw, shallow marine hydrate degassing, and submarine landslides, we find a strong positive feedback on RF through atmospheric chemistry. In particular, the impact of CH4 is enhanced through increase of its lifetime, and of atmospheric abundances of ozone, stratospheric water vapor, and CO2 as a result of atmospheric chemical processes. Despite uncertainties in emission scenarios, our results provide a better understanding of the feedbacks in the atmospheric chemistry that would amplify climate warming.

  15. Equilibrium climate sensitivity in light of observations over the warming hiatus

    NASA Astrophysics Data System (ADS)

    Johansson, Daniel J. A.; O'Neill, Brian C.; Tebaldi, Claudia; Häggström, Olle

    2015-05-01

    A key uncertainty in projecting future climate change is the magnitude of equilibrium climate sensitivity (ECS), that is, the eventual increase in global annual average surface temperature in response to a doubling of atmospheric CO2 concentration. The lower bound of the likely range for ECS given in the IPCC Fifth Assessment Report (AR5; refs , ) was revised downwards to 1.5 °C, from 2 °C in its previous report, mainly as an effect of considering observations over the warming hiatus--the period of slowdown of global average temperature increase since the early 2000s. Here we analyse how estimates of ECS change as observations accumulate over time and estimate the contribution of potential causes to the hiatus. We find that including observations over the hiatus reduces the most likely value for ECS from 2.8 °C to 2.5 °C, but that the lower bound of the 90% range remains stable around 2 °C. We also find that the hiatus is primarily attributable to El Niño/Southern Oscillation-related variability and reduced solar forcing.

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    Global temperature increased by approximately half a degree (Celsius) within the last 150 years. Even this moderate warming had major impacts on Earth's ecological and biological systems, especially in the Arctic where the magnitude of abiotic changes even exceeds those in temperate and tropical biomes. Therefore, understanding the biological consequences of climate change on high latitudes is of critical importance for future conservation of the species living in this habitat. The past 25,000 years can be used as a model for such changes, as they were marked by prominent climatic changes that influenced geographic distribution, demographic history and pattern of genetic variation of many extant species. We sequenced ancient and modern DNA of the collared lemming (Dicrostonyx torquatus), which is a key species of the arctic biota, from a single site (Pymva Shor, Northern Pre Urals, Russia) to see if climate warming events after the Last Glacial Maximum (LGM) had detectable effects on the genetic variation of this arctic rodent species, which is strongly associated with cold and dry climate. Using three dimensional network reconstruction and model-based approaches such as Approximate Bayesian Computation and Markov Chain Monte Carlo based Bayesian inference we show that there is evidence for a population decline in the collared lemming following the LGM, with the population size dropping to a minimum during the Greenland Interstadial 1 (Blling/Allerd) warming phase at 14.5 kyrs BP. Our results show that previous climate warming events had a strong influence on collard lemming populations. A similar population reduction due to predicted future climate change would have severe effects on the arctic ecosystem, as collared lemmings are a key species in the trophic interactions and ecosystem processes in the Arctic.

  17. Permanent El Nino Conditions in the Early Pliocene, the Poleward Heat Transport Paradox, and Contemporary Global Warming

    Microsoft Academic Search

    A. V. Fedorov; C. Brierley

    2007-01-01

    Proxy temperature records show that in the early Pliocene, approximately 3 to 5 million years ago, the tropics were characterized by permanently warm El Nino-like conditions. The equatorial Pacific was as warm as in the east as it is in the west today, and the zonal SST gradient along the equator was significantly reduced or absent. Concurrently, major coastal upwelling

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

    PubMed

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

    2014-08-01

    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

  19. Global warming and climate forcing by recent albedo changes on Mars

    USGS Publications Warehouse

    Fenton, L.K.; Geissler, P.E.; Haberle, R.M.

    2007-01-01

    For hundreds of years, scientists have tracked the changing appearance of Mars, first by hand drawings and later by photographs. Because of this historical record, many classical albedo patterns have long been known to shift in appearance over time. Decadal variations of the martian surface albedo are generally attributed to removal and deposition of small amounts of relatively bright dust on the surface. Large swaths of the surface (up to 56 million km2) have been observed to darken or brighten by 10 per cent or more. It is unknown, however, how these albedo changes affect wind circulation, dust transport and the feedback between these processes and the martian climate. Here we present predictions from a Mars general circulation model, indicating that the observed interannual albedo alterations strongly influence the martian environment. Results indicate enhanced wind stress in recently darkened areas and decreased wind stress in brightened areas, producing a positive feedback system in which the albedo changes strengthen the winds that generate the changes. The simulations also predict a net annual global warming of surface air temperatures by ???0.65 K, enhancing dust lifting by increasing the likelihood of dust devil generation. The increase in global dust lifting by both wind stress and dust devils may affect the mechanisms that trigger large dust storm initiation, a poorly understood phenomenon, unique to Mars. In addition, predicted increases in summertime air temperatures at high southern latitudes would contribute to the rapid and steady scarp retreat that has been observed in the south polar residual ice for the past four Mars years. Our results suggest that documented albedo changes affect recent climate change and large-scale weather patterns on Mars, and thus albedo variations are a necessary component of future atmospheric and climate studies. ??2007 Nature Publishing Group.

  20. Vegetation types and climate conditions reflected by the modern phytolith assemblages in the subalpine Dalaoling Forest Reserve, central China

    NASA Astrophysics Data System (ADS)

    Traoré, Djakanibé Désiré; Gu, Yansheng; Liu, Humei; Shemsanga, Ceven; Ge, Jiwen

    2015-06-01

    This research describes modern phytolith records and distributions from subalpine surface soils in the Dalaoling Forest Reserve, and reveals its implications for local climate conditions with respect to the altitude gradient. Well-preserved phytolith morpho-types, assemblages, and climatic indices were used to study the relationship between local vegetation and climate conditions. The phytolith classification system is mainly based on the characteristics of detailed morpho-types described for anatomical terms, which are divided into seven groups: long cells, short cells, bulliform cells, hair cells, pteridophyte type, broad-leaved type, and gymnosperm type. Phytoliths originating from the Poaceae are composed of Pooideae (rondel and trapeziform), Panicoideae (bilobate, cross, and polylobate), Chloridoideae (short/square saddle), and Bambusoideae (oblong concave saddle). Based on the altitudinal distribution of the phytolith assemblages and the indices of aridity (Iph), climate (Ic), and tree cover density (D/P), five phytolith assemblage zones have revealed the five types of climatic conditions ranging from 1,169 m to 2,005 m in turn: warm-wet, warm-xeric to warm-mesic, warm-xeric to cool-mesic, cool-xeric, and cool-mesic to cool-xeric. The Bambusoideae, Panicoideae, and Chloridoideae are the dominant vegetation at the lower-middle of the mountains, while Pooideae is mainly distributed in the higher mountains. The close relationship between phytolith assembleages and changes of altitude gradient suggest that vegetation distribution patterns and plant ecology in the Dalaoling mountains are controlled by temperature and humidity conditions. Our results highlight the importance of phytolith records as reliable ecoclimatic indicators for vegetation ecology in subtropical regions.

  1. Modeling the Effects of Climate Change on Permafrost in National Parks of Alaska: Will Permafrost Survive the Climate Warming of 21st Century?

    NASA Astrophysics Data System (ADS)

    Panda, S. K.; Marchenko, S. S.; Romanovsky, V. E.; Swanson, D. K.

    2014-12-01

    Permafrost underlies ~70% of all National Park Service administered land in Alaska and it provides a stable foundation to parks' ecosystems and wildlife habitats. However, the strength of this foundation is waning as its temperature is rising in response to recent climate warming. Consequently, thermokarst activities are on the rise and they are altering the parks' landscape, ecosystems, and wildlife habitats. In order to effectively respond to these changes park managers need up-to-date knowledge of the current permafrost temperature and distribution, and how they might evolve with changing climate in the future. To help decision makers understand and respond to the changing permafrost condition, we are modeling near-surface permafrost dynamics—permafrost temperature, distribution, and active layer thickness—in eight national parks of Alaska at a decadal time scale. We are using GIPL 1.0 model (Spatially Distributed Model of Permafrost Dynamics in Alaska), the best available climate inputs, and high-resolution (28 m) ecotype, soil landscape, and snow inputs. Here we present results for two national parks—Denali National Park and Preserve (DENA) and Wrangell-St. Elias National Park and Preserve (WRST). Areas underlain by glaciers and permanent ice-fields were excluded. In DENA, the model suggested near-surface permafrost in 51% of the park area for the 2000 decade, predicted its decline to 6% by 2050s, and 1% by 2090s. In WRST, the model suggested near-surface permafrost in 72% of the park area for the 2000 decade, predicted its decline to 42% by 2050s, and 15% by 2090s. In summary, the near-surface permafrost will likely be degrading in most parts of DENA and WRST towards the end of the current century except at higher elevations where climate models continue to project colder temperature. The modeled maps of DENA and WRST showed 86% and 95% agreement with the field observations of permafrost presence/ absence at 1375 and 430 sites, respectively. In conclusion, the modeled high-resolution permafrost maps show the effect of changing climate on near-surface permafrost. They offer decision makers a clear understanding of how near-surface permafrost distribution in the parks might change in the future, which was lacking up until now, to guide critical monitoring and management decisions.

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

    E-print Network

    Stevenson, Paul

    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

  3. 24 CFR 3285.404 - Severe climatic conditions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Anchorage Against Wind § 3285.404 Severe climatic conditions. In frost-susceptible soil locations, ground anchor augers must be...

  4. 24 CFR 3285.404 - Severe climatic conditions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Anchorage Against Wind § 3285.404 Severe climatic conditions. In frost-susceptible soil locations, ground anchor augers must be...

  5. 24 CFR 3285.404 - Severe climatic conditions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Anchorage Against Wind § 3285.404 Severe climatic conditions. In frost-susceptible soil locations, ground anchor augers must be...

  6. Global Warming

    NSDL National Science Digital Library

    Ms. Schultz

    2007-12-03

    Use the links below to complete your research. The Heat Over Global Warming God and Global Warming Robert Redford: Business Warming Up to Environment Emission Impossible? Senator Stepping Up on Climate Control Interview: Bill McKibben Climate Change and the Media Senate Hearings Five Questions with Environmental Writer Tom Philpott Home Grown Oil, Politics Bribes E2: Energy The Greens Online NewsHour: The Global Warming Debate NewsHour Extra: Global Warming Linked to Humans NewsHour Extra: Global Warming Fears Lead to Ratification of the Kyoto Protocol Frontline: Doubters of Global Warming Journey to Planet Earth: The State of the Planet: Global Warming What s Up With the Weather? Some of the below resources were found in the book Global Warming : Opposing Viewpoints (available in the MRC) The Heritage Foundation - Global Warming Rainforest Alliance Doing a global warming search in this website will result in a list of various articles Sierra Club - homepage eLibrary (Proquest) is now available through the

  7. 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.

  8. Impact of warming climate and cultivar change on maize phenology in the last three decades in North China Plain

    NASA Astrophysics Data System (ADS)

    Xiao, Dengpan; Qi, Yongqing; Shen, Yanjun; Tao, Fulu; Moiwo, Juana P.; Liu, Jianfeng; Wang, Rede; Zhang, He; Liu, Fengshan

    2015-04-01

    As climate change could significantly influence crop phenology and subsequent crop yield, adaptation is a critical mitigation process of the vulnerability of crop growth and production to climate change. Thus, to ensure crop production and food security, there is the need for research on the natural (shifts in crop growth periods) and artificial (shifts in crop cultivars) modes of crop adaptation to climate change. In this study, field observations in 18 stations in North China Plain (NCP) are used in combination with Agricultural Production Systems Simulator (APSIM)-Maize model to analyze the trends in summer maize phenology in relation to climate change and cultivar shift in 1981-2008. Apparent warming in most of the investigated stations causes early flowering and maturity and consequently shortens reproductive growth stage. However, APSIM-Maize model run for four representative stations suggests that cultivar shift delays maturity and thereby prolongs reproductive growth (flowering to maturity) stage by 2.4-3.7 day per decade (d 10a-1). The study suggests a gradual adaptation of maize production process to ongoing climate change in NCP via shifts in high thermal cultivars and phenological processes. It is concluded that cultivation of maize cultivars with longer growth periods and higher thermal requirements could mitigate the negative effects of warming climate on crop production and food security in the NCP study area and beyond.

  9. The effect of abrupt climate changes and climate background conditions in Southern Europe during the last glacial

    NASA Astrophysics Data System (ADS)

    Knorr, Gregor; Martin-Puertas, Celia; Brauer, Achim; Lohmann, Gerrit

    2015-04-01

    The last glacial period is characterized by abrupt and large temperature shifts in Greenland and the North Atlantic realm. Pollen and sediment data from Lago Grande di Monticchio (MON) have demonstrated a clear imprint of these fluctuations operating at millennial time-scales. Interestingly, basic mean environmental condition changes with respect to temperature and precipitation occurred during MIS4, separating warm and dry conditions during MIS5 from relatively cold and humid conditions within MIS3. This general climate background shift is superposed by distinct millennial-scale variability at MON. Using a fully coupled atmosphere-ocean general circulation model applying boundary conditions at 32 ka BP and pre-industrial conditions as a surrogate for MIS3 and MIS5, we have simulated and analysed characteristic changes in Southern Europe during the last glacial. We find that changes in the mean state at MON are mainly related to a partial shift of the North Atlantic deep water (NADW) convection sites from the Nordic Seas to South of Iceland, the presence of the Fennoscandian ice sheet and lower greenhouse gas concentrations. These background characteristics provide the basis for enhanced zonal moisture transport from the eastern North Atlantic to Middle and Southern Europe. Furthermore, simulations of abrupt climate change scenarios show that a deactivation of the convection sites South of Iceland during MIS3 leads to cooler and dryer conditions at MON. Such temperature and precipitation changes are thought to provide a counter-acting effect on woody vegetation and associated pollen signals at MON. This is in contrast to the impact of abrupt climate perturbation scenarios during MIS5, where no significant precipitation changes are detected. Hence, the simulated changes and underlying mechanisms are largely consistent with the recorded proxy evidence with respect to both, mean state and millennial-scale changes.

  10. Energy Partition From Various Climate Conditions And Land Use Types

    NASA Astrophysics Data System (ADS)

    Cheng, Chi-Han; Hsu2, Pang-Chi

    2015-04-01

    Investigating how energy partitions and what factors control energy exchange is critical for better understanding the hydrological cycle, boundary layer dynamics, and land -atmosphere coupling. Climate and land use conditions are the two main factors to control energy partitation. However, previous studies discussed energy partition and factors that controlled Bowen ratio (i.e., ratio of sensible heat flux to latent heat flux) in limited land use types and climate conditions. To provide a more comprehensive analysis over various climate and vegetation types, in this study, we studied eleven different land use types in the eight different climate zones within the United State. The results found out that the Mediterranean climate zone with dry summer season, dry arid (desert) climate zone, and the higher latitude area with severe winter would had higher Bowen ratio, lower precipitation and net radiation. In contrast, the humid climate zones had the lower Bowen ratio, higher net radiation and precipitation. Moreover, the higher Bowen ratio usually happened in the winter or early spring seasons. Regarding land conditions, it is found that soil moistures are the key factor to control Bowen ratio in the drier climate areas. Hence, the grassland and closed shrublands sites have higher Bowen ratio than deciduous broadleaf forests and evergreen needle-leaf forests sites' because of shallower root systems that lack access to the full storage of water in the vadose zone. However, in the humid areas, land use factors, such as stomatal resistance and leaf area, would play an important role in changing latent heat and sensible heat. Based on the tight relationships between Bowen ratio and conditions of climate and land use, we suggest that Bowen ratio could be a useful tool for understanding the potential feedbacks of changes in climate and land use to energy partition and exchange.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    Recent studies on the effects of global warming on fish populations reveal that the resulting hypoxia-based habitat compression due to the expansion of the oxygen minimum zone may lead to the restriction of fish depth distributions to the oxygenated near-surface layer1. Here we postulate that similar phenomena may have affected the fish distribution in the early Pliocene Heraklion semi-enclosed sea (Crete, eastern Mediterranean). Fish otoliths from Voutes section are systematically identified and the data is examined from a palaeoecologic perspective in response to the Pliocene climatic variability. Bregmaceros and Diaphus taaningi otoliths' relative abundances are used as reliable palaeoclimatic indicators2. The Voutes section sediments contain a very rich fish fauna. Diaphus spp., Bregmaceros sp., Sardinella maderensis, Phosichthyidae and Sternoptychyidae form the pelagic component. Mesopelagic taxa belong mostly to Myctophids. The benthopelagic and benthic component of the fish fauna is very well diversified and is comprised of Gobiids, such as Gobius cf. niger, Callogobius sp., Lesueurigobius aff. sanzoi, and Aphya sp., as well as Gadiculus labiatus, Laemonema sp., Oblada melanura, Parascombrus mutinensis, Barbourisia rufa, Blennius sp., Ammodytes sp., Solea aff. solea. The presence of Oligopus sp., Spratelloides sp., and Brotula cf. mutlibarbata in the middle part of the section indicate the development of a reef in the study area. The palaeoecologic analysis of the surface, intermediate and deep water faunal groups indicate that the pelagic fish populations in the semi-enclosed early Pliocene Heraklion basin directly reflect the climatic variability. However, the intermediate and deep water fish did not respond to climate change in the same manner. Indeed, two dysoxic events are recorded in this section, where the pelagic component of the fauna is almost exclusively comprised of Bregmaceros sp., few Myctophids are present, and the benthic and benthopelagic taxa are nearly non-existent. These events are intermitted by the development of a reef system near the study area, marked by the intense diversification of the fish fauna on all water levels. The mollusc fauna turnover reinforces the above results. Conclusively, the present study clearly presents the fish populations' dynamic characteristics of in response to climatic variability. Acknowledgments This research has been co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: Heracleitus II. Investing in knowledge society through the European Social Fund.

  12. Effects of airflow on body temperatures and sleep stages in a warm humid climate

    NASA Astrophysics Data System (ADS)

    Tsuzuki, Kazuyo; Okamoto-Mizuno, Kazue; Mizuno, Koh; Iwaki, Tatsuya

    2008-03-01

    Airflow is an effective way to increase heat loss—an ongoing process during sleep and wakefulness in daily life. However, it is unclear whether airflow stimulates cutaneous sensation and disturbs sleep or reduces the heat load and facilitates sleep. In this study, 17 male subjects wearing short pyjamas slept on a bed with a cotton blanket under two of the following conditions: (1) air temperature (Ta) 26°C, relative humidity (RH) 50%, and air velocity (V) 0.2 m s-1; (2) Ta 32°C, RH 80%, V 1.7 m s-1; (3) Ta 32°C; RH 80%, V 0.2 m s-1 (hereafter referred to as 26/50, 32/80 with airflow, and 32/80 with still air, respectively). Electroencephalograms, electrooculograms, and mental electromyograms were obtained for all subjects. Rectal (Tre) and skin (Ts) temperatures were recorded continuously during the sleep session, and body-mass was measured before and after the sleep session. No significant differences were observed in the duration of sleep stages between subjects under the 26/50 and 32/80 with airflow conditions; however, the total duration of wakefulness decreased significantly in subjects under the 32/80 with airflow condition compared to that in subjects under the 32/80 with still air condition ( P < 0.05). Tre, Tsk, Ts, and body-mass loss under the 32/80 with airflow condition were significantly higher compared to those under the 26/50 condition, and significantly lower than those under the 32/80 with still air condition ( P < 0.05). An alleviated heat load due to increased airflow was considered to exist between the 32/80 with still air and the 26/50 conditions. Airflow reduces the duration of wakefulness by decreasing Tre, Tsk, Ts, and body-mass loss in a warm humid condition.

  13. Variability to sedimentary dynamics and climatic conditions during the last two millennia at sebkha Souassi in eastern Tunisia

    NASA Astrophysics Data System (ADS)

    Essefi, Elhoucine; Jmaa, Hayet Ben; Touir, Jamel; Tagortig, Mohamed Ali; Yaicha, Chokri

    2013-01-01

    This paper covers work intended to study the interplay of sedimentary dynamics and climatic variability over the last two millennia within Tunisia's sebkha Souassi. Based on the Visual Core Description, and magnetic susceptibility, we date the core from sebkha Souassi to the last two millennia. Genetic grain-size distribution then provided a basis for the identification of six climatic stages, i.e. the Warming Present (WP), the Late Little Ice Age (Late LIA), the Early Little Ice Age (ELIA), the Medieval Climatic Anomaly (MCA), the Dark Ages (DA), and the Roman Warm Period (RWP). The WP stretches across the uppermost 3 cm, with a high grey scale indicating a dry climate. The Late LIA is located between 3 and 7 cm, and the ELIA between 7 and 28 cm. Intermediate values for GS indicate that this stage may be classified as moderate. The MCA spanning from 28 to 40 cm is marked by a sharp decrease in GS indicative of a wet period. The DA appear along the part between 40 and 79 cm, a shift from light to dark sediments being recorded. The RWP in turn appears between 79 and 114 cm. Based on the grain-size distribution, two low-frequency cycles were identified, indicating radical global changes in climatic conditions, differential tectonics and groundwater fluctuations. High-frequency cycles in turn attest to local modifications of climatic conditions.

  14. Comparison of global warming impacts of automobile air-conditioning concepts

    SciTech Connect

    NONE

    1995-12-31

    The global warming impacts of conventional vapor compression automobile air conditioning using HFC-134a are compared with the potential impacts of four alternative concepts. Comparisons are made on the basis of total equivalent warming impact (TEWI) which accounts for the effects of refrigerant emissions, energy use to provide comfort cooling, and fuel consumed to transport the weight of the air conditioning system. Under the most favorable assumptions on efficiency and weight, transcritical compression using CO{sub 2} as the refrigerant and adsorption cooling with water and zeolite beds could reduce TEWI by up to 18%rlative to HFC-134a compression air conditioning. Other assumptions on weight and efficiency lead to significant increases in TEWI relative to HFC-134a, and it is impossible to determine which set of assumptios is valid from existing data, Neither Stirling cycle or thermoelectric cooling will reduce TEWI relative to EFC-134a. Brief comments are also made concerning technical barriers that must be overcome for succesful development of the new technologies.

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

    NASA Astrophysics Data System (ADS)

    Zhuang, Weimin; Zhang, Mengxi; Chen, Yanhong

    2014-07-01

    Forming limit curves(FLCs) are commonly used for evaluating the formability of sheet metals. However, it is difficult to obtain the FLCs with desirable accuracy by experiments due to that the friction effects are non-negligible under warm/hot stamping conditions. To investigate the experimental errors, experiments for obtaining the FLCs of the AA5754 are conducted at 250°C. Then, FE models are created and validated on the basis of experimental results. A number of FE simulations are carried out for FLC test-pieces and punches with different geometry configurations and varying friction coefficients between the test-piece and the punch. The errors for all the test conditions are predicted and analyzed. Particular attention of error analysis is paid to two special cases, namely, the biaxial FLC test and the uniaxial FLC test. The failure location and the variation of the error with respect to the friction coefficient are studied as well. The results obtained from the FLC tests and the above analyses show that, for the biaxial tension state, the friction coefficient should be controlled within 0.15 to avoid significant shifting of the necking location away from the center of the punch; for the uniaxial tension state, the friction coefficient should be controlled within 0.1 to guarantee the validity of the data collected from FLC tests. The conclusions summarized are beneficial for obtaining accurate FLCs under warm/hot stamping conditions.

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

    NASA Astrophysics Data System (ADS)

    Overland, James E.; Stabeno, Phyllis J.

    2004-08-01

    Observations from the Bering Sea are good indicators of decadal shifts in climate, as the Bering is a transition region between the cold, dry Arctic air mass to the north, and the moist, relatively warm maritime air mass to the south. The Bering Sea is also a transition region between Arctic and sub-Arctic ecosystems; this boundary can be loosely identified with the extent of winter sea-ice cover. Like a similar transition zone in the eastern North Atlantic, the Bering Sea is experiencing a northward biogeographical shift in response to changing temperature and atmospheric forcing. If this shift continues over the next decade, it will have major impacts on commercial and subsistence harvests as Arctic species are displaced by sub-Arctic species. The stakes are enormous, as this rich and diverse ecosystem currently provides 47% of the U.S. fishery production by weight, and is home to 80% of the U.S. sea bird population, 95% of northern fur seals, and major populations of Steller sea lions, walrus, and whales.

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

    PubMed

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

    2010-01-01

    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

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

    NASA Astrophysics Data System (ADS)

    Lapenis, Andrei; Lawrence, Gregory; Buyantuev, Alexander

    2015-04-01

    Increased greening of northern forests, measured by the Normalized Difference Vegetation Index (NDVI), has been presented as evidence that a warmer climate has increased both net primary productivity (NPP) and the carbon sink in boreal forests. However, higher production and greener canopies may accompany changes in carbon allocation that favor foliage or fine roots over less decomposable woody biomass. Furthermore, tree core data throughout mid- and northern latitudes have revealed a divergence problem (DP), a weakening in tree ring responses to warming over the past half century that is receiving increasing attention, but remains poorly understood. Often, the same sites exhibit trend inconsistency phenomenon (TIP), namely positive, or no trends in growing season NDVI where negative trends in tree ring indexes are observed. Here we studied growth of two Norway spruce (Picea abies) stands in western Russia that exhibited both the DP and TIP but were subject to soil acidification and calcium depletion of differing timing and severity. Our results link the decline in radial growth starting in 1980 to a shift in carbon allocation from wood to roots driven by a combination of two factors: (a) soil acidification that depleted calcium and impaired root function and (b) earlier onset of the growing season that further taxed the root system. The latter change in phenology appears to act as a trigger at both sites to push trees into nutrient limitation as the demand for Ca increased with the longer growing season, thereby causing the shift in carbon allocation.

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

    PubMed

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

    2012-06-19

    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

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

    USGS Publications Warehouse

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

    2013-01-01

    Increased greening of northern forests, measured by the Normalized Difference Vegetation Index (NDVI), has been presented as evidence that a warmer climate has increased both net primary productivity (NPP) and the carbon sink in boreal forests. However, higher production and greener canopies may accompany changes in carbon allocation that favor foliage or fine roots over less decomposable woody biomass. Furthermore, tree core data throughout mid- and northern latitudes have revealed a divergence problem (DP), a weakening in tree ring responses to warming over the past half century that is receiving increasing attention, but remains poorly understood. Often, the same sites exhibit trend inconsistency phenomenon (TIP), namely positive, or no trends in growing season NDVI where negative trends in tree ring indexes are observed. Here we studied growth of two Norway spruce (Picea abies) stands in western Russia that exhibited both the DP and TIP but were subject to soil acidification and calcium depletion of differing timing and severity. Our results link the decline in radial growth starting in 1980 to a shift in carbon allocation from wood to roots driven by a combination of two factors: (a) soil acidification that depleted calcium and impaired root function and (b) earlier onset of the growing season that further taxed the root system. The latter change in phenology appears to act as a trigger at both sites to push trees into nutrient limitation as the demand for Ca increased with the longer growing season, thereby causing the shift in carbon allocation.

  1. Arctic lakes are continuous methane sources to the atmosphere under warming conditions

    NASA Astrophysics Data System (ADS)

    Tan, Zeli; Zhuang, Qianlai

    2015-05-01

    Methane is the second most powerful carbon-based greenhouse gas in the atmosphere and its production in the natural environment through methanogenesis is positively correlated with temperature. Recent field studies showed that methane emissions from Arctic thermokarst lakes are significant and could increase by two- to four-fold due to global warming. But the estimates of this source are still poorly constrained. By using a process-based climate-sensitive lake biogeochemical model, we estimated that the total amount of methane emissions from Arctic lakes is 11.86 Tg yr?1, which is in the range of recent estimates of 7.1–17.3 Tg yr?1 and is on the same order of methane emissions from northern high-latitude wetlands. The methane emission rate varies spatially over high latitudes from 110.8 mg CH4 m?2 day?1 in Alaska to 12.7 mg CH4 m?2 day?1 in northern Europe. Under Representative Concentration Pathways (RCP) 2.6 and 8.5 future climate scenarios, methane emissions from Arctic lakes will increase by 10.3 and 16.2 Tg CH4 yr?1, respectively, by the end of the 21st century.

  2. Modeling the potential change in yield and distribution of the earth's crops under a warmed climate

    SciTech Connect

    Leemans, R.; Solomon, A.M.

    1993-01-01

    The large scale distribution of crops is largely determined by climate. The authors present the results of a climate-crop prediction model based on the U.N. Food and Agriculture Organization crop-suitability approach, implemented in a geographic information system (GIS) environment using several global environmental databases. The model utilizes daily temperature and moisture conditions to determine the properties of the growing period. Crops are characterized by their variety-specific minimum growing period requirements and photosynthesis and respiration properties. Temperature and solar radiation during the growing period control the development of each crop. The model simulates crop-specific geographic distributions by demarcating the region where productivity is possible. The model takes only non-irrigated crop productivity into account and the potential increase in productivity by technological means is not considered. The model therefore shows no crop growth along major rivers in arid, often irrigated, regions. (Copyright (c) Inter-Research 1993.)

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

    PubMed Central

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

    2012-01-01

    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

  4. Impacts of climate warming and permafrost thaw on the riverine transport of nitrogen and phosphorus to the Kara Sea

    Microsoft Academic Search

    Karen E. Frey; James W. McClelland; Robert M. Holmes; Laurence C. Smith

    2007-01-01

    Measurements of nitrogen and phosphorus (N and P) concentrations from previously unstudied streams and rivers throughout west Siberia suggest that climate warming and\\/or associated permafrost thaw will likely amplify the transport of N and P to the Kara Sea and adjacent Arctic Ocean. We present concentrations of dissolved organic nitrogen (DON), ammonium (NH4-N), nitrate (NO3-N), total dissolved nitrogen (TDN), and

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

    E-print Network

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

    2006-01-01

    WARM-HUMID CLIMATE: METHODOLOGY TO STUDY AIR TEMPERATURE DISTRIBUTION: MOBILE PHONES BASE STATIONS AS VIABLE ALTERNATIVE FOR FIXED POINTS Angelina Dias Leão Costa (1); Lucila Labaki (2); Virgínia Araújo (3) (1) and (2) School of Civil..., in February 2006, are presented. The fixed points were defined using 20 mobile phone base stations in the city of Natal/RN, distributed along the four administrative zones. Measurements were carried out for seven days, registering air temperature...

  6. Late Noachian to Hesperian climate change on Mars: Evidence of episodic warming from transient crater lakes near Ares Vallis

    Microsoft Academic Search

    Nick Warner; Sanjeev Gupta; Shih-Yuan Lin; Jung-Rack Kim; Jan-Peter Muller; Jeremy Morley

    2010-01-01

    The Ares Vallis region is surrounded by highland terrain containing both degraded and pristine large impact craters that suggest a change in climate during the Late Noachian-Early Hesperian, from warmer, wetter conditions to colder, dryer conditions. However, the regional occurrence of Hesperian-age crater outlet channels indicates that this period on Mars was characterized by episodic climate fluctuations that caused transient

  7. Towards understanding orbital scale climate dynamics in the early Pliocene warm world

    NASA Astrophysics Data System (ADS)

    Bell, D.; Jung, S.; Kroon, D.; Hodell, D.; Lourens, L.

    2012-04-01

    Benthic d18O records are an essential tool for understanding orbital-scale dynamics of the Earth's climate. The early Pliocene (~5.3-3.7Ma) is of particular interest as it can elucidate important climate feedbacks operating during periods of reduced ice and sustained warmth, such as what is expected in near future conditions. Consequently, the development of a high-resolution early Pliocene d18O stratigraphy is fundamental to advancing our understanding of how the Earth's climate operates in a greenhouse world. Currently, however, the number of early Pliocene benthic d18O records is low, spatial coverage is poor and sample resolution is variable, as compared with the late Pleistocene. Here, we present a newly established ~5.3-0Ma benthic d18O record from ODP Site 1264 (2505m) on Walvis Ridge. Our early Pliocene section has the highest sample resolution of any published record (~1.3-kyrs). We explore two alternative, orbitally tuned, age models in order to assess the optimal chronology for our early Pliocene section. We find that early Pliocne Marine Isotope Stages, as established by Lisiecki & Raymo (2005), are not well expressed at our site, leading to significant uncertainty in correlation to the LR04 stack. Comparison with other available early Pliocene records shows that this issue is not unique to our site. Furthermore, spectral analysis shows that the benthic d18O response to orbital forcing is considerably diminished when records are aligned to the LR04 stack, compared to independently tuned age models. The low amplitude of variability in early Pliocene benthic d18O records, and differences between them, necessitates that local temperature and salinity conditions have a strong influence on the d18O signal, potentially dominating over the ice volume effect. Hence, we suggest that stacking globally distributed d18O records, during periods of low ice volume variability, directly limits our ability to understand the climatic response to orbital forcing and create reliable stratigraphies.

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

    PubMed

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

    2013-06-01

    Our Earth is facing the challenge of accelerating climate change, which imposes a great threat to biodiversity. Many published studies suggest that climate warming may cause a dramatic decline in biodiversity, especially in colder and drier regions. In this study, we investigated the effects of temperature, precipitation and a normalized difference vegetation index on biodiversity indices of rodent communities in the current or previous year for both detrended and nondetrended data in semi-arid grassland of Inner Mongolia during 1982-2006. Our results demonstrate that temperature showed predominantly positive effects on the biodiversity of small rodents; precipitation showed both positive and negative effects; a normalized difference vegetation index showed positive effects; and cross-correlation function values between rodent abundance and temperature were negatively correlated with rodent abundance. Our results suggest that recent climate warming increased the biodiversity of small rodents by providing more benefits to population growth of rare or less abundant species than that of more abundant species in Inner Mongolia grassland, which does not support the popular view that global warming would decrease biodiversity in colder and drier regions. We hypothesized that higher temperatures might benefit rare or less abundant species (with smaller populations and more folivorous diets) by reducing the probability of local extinction and/or by increasing herbaceous food resources. PMID:23731812

  9. Middle Miocene tectonic boundary conditions for use in climate models

    E-print Network

    Müller, Dietmar

    Middle Miocene tectonic boundary conditions for use in climate models N. Herold, M. Seton, and R. D model boundary conditions. We present a middle Miocene paleotopographic and paleobathymetric is reconstructed through application of an age-depth relationship to a middle Miocene global digital isochron map

  10. HEAT STRESS CLIMATIC CONDITIONS AND THE PHYSIOLOGICAL RESPONSES OF CATTLE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle are adaptable to a wide range of climatic conditions, but can be severely challenged by sudden heat waves. Repeated hot, humid environments, with little air flow or cloud cover, are periods of concern, especially if conditions persist over a three-day period without significant nighttime reli...

  11. Warming-enhanced preferential microbial mineralization of humified boreal forest soil organic matter: Interpretation of soil profiles along a climate transect using laboratory incubations

    E-print Network

    Li, Jianwei; Ziegler, Susan; Lane, Chad S.; Billings, Sharon A.

    2012-06-01

    Humified soil organic matter storage in boreal forests is large, and its responses to warming over relatively long timescales is critical for predicting soil feedbacks to climate change. To derive information relevant across decades to centuries...

  12. Future Variations of Wave Climate in Winter Japan: Application of Pseudo Global Warming Dynamic Downscaling Method for CMIP5 output and a Wave Model Simulation

    NASA Astrophysics Data System (ADS)

    Taniguchi, K.

    2014-12-01

    Ocean waves change alongshore topographies and their effects reach to ecological systems and coastal infrastructures. Ocean waves are mainly formed by sea surface wind, then variations in sea surface winds can cause changes in ocean waves. Under the condition of global warming, atmospheric motion will change in future climate and they will give changes in wave climates. However, effects of global warming on wave climate have not yet investigated in detail. In this study, a dynamic downscaling method by a weather prediction model (WRF developed by NCAR) is applied to obtain detail information of sea surface wind in the present and future climates. The ocean wave is simulated by a wave model (WaveWatch-III developed by NOAA) with the downscaled wind in the present and future climate, then variations in wave climate in future are investigated. For future climate, climate projections in Coupled Model Intercomparison Project phase 5 (CMIP5) are used. For future scenario, the representative concentrate pathways 4.5 (RCP4.5) is selected. Variations of ocean waves in the Sea of Japan is focused in this work. Over the Sea of Japan, the strong northwesterly blows from the Eurasian Continent to the Japan islands in winter and causes high waves, and sometimes it causes marine accidents and breaks in coastal civil structures. The results of WaveWatch-III showed that the maximum value of significant wave height becomes smaller in the northern and central part of the Sea of Japan, however, clear increases are found in the southern part in future. In some regions, the maximum wave heights in future become 4 meter larger than in present. On the other hand, there are variations in frequency distribution of significant wave height. The frequency of modestly high waves increases and the low wave frequency decreases mainly in January and February (even in areas with smaller maximum significant wave height in future). Without extremely high ocean waves, variations in frequency distribution on ocean wave will affect alongshore sediment transport and topography.

  13. Expansion of dwarf birch in subarctic Québec: linking radial growth to climate warming

    NASA Astrophysics Data System (ADS)

    Ropars, P.; Boudreau, S.

    2010-12-01

    In subarctic regions of North America, shrub species have been shown to increase in abundance in response to recent climate change. At the forest-tundra ecotone in northern Québec, the shrub layer is dominated by dwarf birch (Betula glandulosa Michx.), a deciduous species that can reproduce sexually via the production of viable seeds or asexually through clonal growth. Its morphological plasticity is often mentioned to explain its high sensibility to experimental warming. In this study, our objectives were to evaluate if recent warming recorded in subarctic Québec has resulted in dwarf birch expansion and densification in the last few decades and in an increase in its radial growth. This study took place in the Boniface river region, Nunavik (57° 45’ N, 76° 20’ W). In order to quantify the change in birch cover, we compared two sets of orthorectified aerial photographs (July 1957 and July 2008; resolution 1.0m and 0.5m, respectively). Fifty sites located on well-drained substrate ranging from 8 000 and 14 400 m2 have been selected. For each site, a 16m2-cell grid was superimposed on both orthoimages and shrub cover class was estimated in each cells. Preliminary results suggest that shrub cover increase ranges from 17.02 to 54.03%. No site showed a decrease of mean shrub cover between 1957 and 2008. On the other hand, we have found a decline in the percentage of cells having no shrub cover, from 46% in 1957 to 17% in 2008. An exhaustive ground truthing exercise confirmed that Betula glandulosa was the major shrub species responsible for the increase in shrub cover in the studied sites. The rapid expansion and densification of the shrub layer could have important ecological consequences in the region. Dense thickets of dwarf birch could actually interfere with future tree establishment and limit the progression of the latitudinal treeline in the short term. The dendrochronological analysis is based on 360 individuals of dwarf birch (40 individuals taken from 9 different sites). Preliminary results of this analysis revealed that Betula glandulosa growth is related to summer temperatures. Therefore, increased radial growth could translate to greater viable seed production and greater seedling establishment.

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

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2007-05-01

    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.

  16. Protected Area Tourism in a Changing Climate: Will Visitation at US National Parks Warm Up or Overheat?

    PubMed Central

    Fisichelli, Nicholas A.; Schuurman, Gregor W.; Monahan, William B.; Ziesler, Pamela S.

    2015-01-01

    Climate change will affect not only natural and cultural resources within protected areas but also tourism and visitation patterns. The U.S. National Park Service systematically collects data regarding its 270+ million annual recreation visits, and therefore provides an opportunity to examine how human visitation may respond to climate change from the tropics to the polar regions. To assess the relationship between climate and park visitation, we evaluated historical monthly mean air temperature and visitation data (1979–2013) at 340 parks and projected potential future visitation (2041–2060) based on two warming-climate scenarios and two visitation-growth scenarios. For the entire park system a third-order polynomial temperature model explained 69% of the variation in historical visitation trends. Visitation generally increased with increasing average monthly temperature, but decreased strongly with temperatures > 25°C. Linear to polynomial monthly temperature models also explained historical visitation at individual parks (R2 0.12-0.99, mean = 0.79, median = 0.87). Future visitation at almost all parks (95%) may change based on historical temperature, historical visitation, and future temperature projections. Warming-mediated increases in potential visitation are projected for most months in most parks (67–77% of months; range across future scenarios), resulting in future increases in total annual visits across the park system (8–23%) and expansion of the visitation season at individual parks (13–31 days). Although very warm months at some parks may see decreases in future visitation, this potential change represents a relatively small proportion of visitation across the national park system. A changing climate is likely to have cascading and complex effects on protected area visitation, management, and local economies. Results suggest that protected areas and neighboring communities that develop adaptation strategies for these changes may be able to both capitalize on opportunities and minimize detriment related to changing visitation. PMID:26083361

  17. Protected Area Tourism in a Changing Climate: Will Visitation at US National Parks Warm Up or Overheat?

    PubMed

    Fisichelli, Nicholas A; Schuurman, Gregor W; Monahan, William B; Ziesler, Pamela S

    2015-01-01

    Climate change will affect not only natural and cultural resources within protected areas but also tourism and visitation patterns. The U.S. National Park Service systematically collects data regarding its 270+ million annual recreation visits, and therefore provides an opportunity to examine how human visitation may respond to climate change from the tropics to the polar regions. To assess the relationship between climate and park visitation, we evaluated historical monthly mean air temperature and visitation data (1979-2013) at 340 parks and projected potential future visitation (2041-2060) based on two warming-climate scenarios and two visitation-growth scenarios. For the entire park system a third-order polynomial temperature model explained 69% of the variation in historical visitation trends. Visitation generally increased with increasing average monthly temperature, but decreased strongly with temperatures > 25°C. Linear to polynomial monthly temperature models also explained historical visitation at individual parks (R2 0.12-0.99, mean = 0.79, median = 0.87). Future visitation at almost all parks (95%) may change based on historical temperature, historical visitation, and future temperature projections. Warming-mediated increases in potential visitation are projected for most months in most parks (67-77% of months; range across future scenarios), resulting in future increases in total annual visits across the park system (8-23%) and expansion of the visitation season at individual parks (13-31 days). Although very warm months at some parks may see decreases in future visitation, this potential change represents a relatively small proportion of visitation across the national park system. A changing climate is likely to have cascading and complex effects on protected area visitation, management, and local economies. Results suggest that protected areas and neighboring communities that develop adaptation strategies for these changes may be able to both capitalize on opportunities and minimize detriment related to changing visitation. PMID:26083361

  18. Fungal Diversity in Permafrost and Tallgrass Prairie Soils under Experimental Warming Conditions

    PubMed Central

    StLouis, Derek; Cole, James R.; Luo, Yiqi; Wu, Liyou; Schuur, E. A. G; Zhou, Jizhong; Tiedje, James M.

    2013-01-01

    Soil fungi play a major role in terrestrial ecosystem functioning through interactions with soil structure, plants, micro- and mesofauna, and nutrient cycling through predation, pathogenesis, mutualistic, and saprotrophic roles. The diversity of soil fungi was assessed by sequencing their 28S rRNA gene in Alaskan permafrost and Oklahoma tallgrass prairie soils at experimental sites where the effect of climate warming is under investigation. A total of 226,695 reads were classified into 1,063 genera, covering 62% of the reference data set. Using the Bayesian Classifier offered by the Ribosomal Database Project (RDP) with 50% bootstrapping classification confidence, approximately 70% of sequences were returned as “unclassified” at the genus level, although the majority (?65%) were classified at the class level, which provided insight into these lesser-known fungal lineages. Those unclassified at the genus level were subjected to BLAST analysis against the ARB-SILVA database, where ?50% most closely matched nonfungal taxa. Compared to the more abundant sequences, a higher proportion of rare operational taxonomic units (OTU) were successfully classified to genera at 50% bootstrap confidence, indicating that the fungal rare biosphere in these sites is not composed of sequencing artifacts. There was no significant effect after 1 year of warming on the fungal community structure at both sites, except perhaps for a few minor members, but there was a significant effect of sample depth in the permafrost soils. Despite overall significant community structure differences driven by variations in OTU dominance, the prairie and permafrost soils shared 90% and 63% of all fungal sequences, respectively, indicating a fungal “seed bank” common between both sites. PMID:24014534

  19. The dynamic response of the Greenland and Antarctic ice sheets to multiple-century climatic warming

    SciTech Connect

    Huybrechts, P. [Vrije Universiteit Brussel, Brussels (Belgium). Dept. Geografie] [Vrije Universiteit Brussel, Brussels (Belgium). Dept. Geografie; Wolde, J. de [Universiteit Utrecht (Netherlands). Instituut voor Marien en Atmosferische Onderzoek] [Universiteit Utrecht (Netherlands). Instituut voor Marien en Atmosferische Onderzoek

    1999-08-01

    New calculations were performed to investigate the combined response of the Greenland and Antarctic ice sheets to a range of climatic warming scenarios over the next millennium. Use was made of fully dynamic 3D thermomechanic ice sheet models, which were coupled to a two-dimensional climate model. The experiments were initialized with simulations over the last two glacial cycles to estimate the present evolution and were subsequently forced with temperature scenarios resulting from greenhouse emission scenarios which assume equivalent CO{sub 2} increases of two, four, and eight times the present (1990 A.D.) value by the year 2130 A.D. and a stabilization after that. The calculations brought to light that during the next century (short-term effect), the background evolution trend would dominate the response of the Antarctic ice sheet but would be negligible for the Greenland ice sheet. On that timescale, the Greenland and Antarctic ice sheets would roughly balance one another for the middle scenario (similar to the IPCC96 IS92a scenario), with respective contributions to the worldwide sea level stand on the order of about {+-}10 cm. On the longer term, however, both ice sheets would contribute positively to the worldwide sea level stand and the most important effect would come from melting on the Greenland ice sheet. Sensitivity experiments highlighted the role of ice dynamics and the height-mass-balance feedback on the results. It was found that ice dynamics cannot be neglected for the Greenland ice sheet, not even on a century timescale, but becomes only important for Antarctica on the longer term. The latter is related to an increased outflow of ice into the ice shelves and to the grounding-line retreat of the west Antarctic ice sheet, which are both found to be sensitive to basal melting below ice shelves and the effective viscosity of the ice shelves. Stretching parameters to their limits yielded a combined maximum rate of sea level rise of 85 cm century{sup {minus}1}, of which 60 cm would originate from the Greenland ice sheet alone.

  20. Variability in krill biomass links harvesting and climate warming to penguin population changes in Antarctica

    PubMed Central

    Trivelpiece, Wayne Z.; Hinke, Jefferson T.; Miller, Aileen K.; Reiss, Christian S.; Trivelpiece, Susan G.

    2011-01-01

    The West Antarctic Peninsula (WAP) and adjacent Scotia Sea support abundant wildlife populations, many of which were nearly extirpated by humans. This region is also among the fastest-warming areas on the planet, with 5–6 °C increases in mean winter air temperatures and associated decreases in winter sea-ice cover. These biological and physical perturbations have affected the ecosystem profoundly. One hypothesis guiding ecological interpretations of changes in top predator populations in this region, the “sea-ice hypothesis,” proposes that reductions in winter sea ice have led directly to declines in “ice-loving” species by decreasing their winter habitat, while populations of “ice-avoiding” species have increased. However, 30 y of field studies and recent surveys of penguins throughout the WAP and Scotia Sea demonstrate this mechanism is not controlling penguin populations; populations of both ice-loving Adélie and ice-avoiding chinstrap penguins have declined significantly. We argue in favor of an alternative, more robust hypothesis that attributes both increases and decreases in penguin populations to changes in the abundance of their main prey, Antarctic krill. Unlike many other predators in this region, Adélie and chinstrap penguins were never directly harvested by man; thus, their population trajectories track the impacts of biological and environmental changes in this ecosystem. Linking trends in penguin abundance with trends in krill biomass explains why populations of Adélie and chinstrap penguins increased after competitors (fur seals, baleen whales, and some fishes) were nearly extirpated in the 19th to mid-20th centuries and currently are decreasing in response to climate change. PMID:21482793

  1. Variability in krill biomass links harvesting and climate warming to penguin population changes in Antarctica.

    PubMed

    Trivelpiece, Wayne Z; Hinke, Jefferson T; Miller, Aileen K; Reiss, Christian S; Trivelpiece, Susan G; Watters, George M

    2011-05-01

    The West Antarctic Peninsula (WAP) and adjacent Scotia Sea support abundant wildlife populations, many of which were nearly extirpated by humans. This region is also among the fastest-warming areas on the planet, with 5-6 °C increases in mean winter air temperatures and associated decreases in winter sea-ice cover. These biological and physical perturbations have affected the ecosystem profoundly. One hypothesis guiding ecological interpretations of changes in top predator populations in this region, the "sea-ice hypothesis," proposes that reductions in winter sea ice have led directly to declines in "ice-loving" species by decreasing their winter habitat, while populations of "ice-avoiding" species have increased. However, 30 y of field studies and recent surveys of penguins throughout the WAP and Scotia Sea demonstrate this mechanism is not controlling penguin populations; populations of both ice-loving Adélie and ice-avoiding chinstrap penguins have declined significantly. We argue in favor of an alternative, more robust hypothesis that attributes both increases and decreases in penguin populations to changes in the abundance of their main prey, Antarctic krill. Unlike many other predators in this region, Adélie and chinstrap penguins were never directly harvested by man; thus, their population trajectories track the impacts of biological and environmental changes in this ecosystem. Linking trends in penguin abundance with trends in krill biomass explains why populations of Adélie and chinstrap penguins increased after competitors (fur seals, baleen whales, and some fishes) were nearly extirpated in the 19th to mid-20th centuries and currently are decreasing in response to climate change. PMID:21482793

  2. Effects of excess ground ice on projections of permafrost in a warming climate

    NASA Astrophysics Data System (ADS)

    Lee, Hanna; Swenson, Sean C.; Slater, Andrew G.; Lawrence, David M.

    2014-12-01

    In permafrost soils, ‘excess ice’, also referred to as ground ice, exists in amounts exceeding soil porosity in forms such as ice lenses and wedges. Here, we incorporate a simple representation of excess ice in the Community Land Model (CLM4.5) to investigate how excess ice affects projected permafrost thaw and associated hydrologic responses. We initialize spatially explicit excess ice obtained from the Circum-Arctic Map of Permafrost and Ground-Ice Conditions. The excess ice in the model acts to slightly reduce projected soil warming by about 0.35 °C by 2100 in a high greenhouse gas emissions scenario. The presence of excess ice slows permafrost thaw at a given location with about a 10 year delay in permafrost thaw at 3 m depth at most high excess ice locations. The soil moisture response to excess ice melt is transient and depends largely on the timing of thaw with wetter/saturated soil moisture conditions persisting slightly longer due to delayed post-thaw drainage. Based on the model projections of excess ice melt, we can estimate spatially explicit gridcell mean surface subsidence with values ranging up to 0.5 m by 2100 depending on the initial excess ice content and the extent of melt.

  3. Assessing the impacts of extended drought conditions and global warming on groundwater resources in Iowa

    NASA Astrophysics Data System (ADS)

    Acar, O.; Franz, K.; Simpkins, W. W.

    2013-12-01

    Extended drought conditions that affected much of the U.S. throughout 2012 and continued into 2013 are bringing climate change to the forefront of public attention. Long-term effects of an extended dry spell on groundwater is especially concerning as these resources are essential for meeting drinking water demands, supporting agricultural and industrial activities, and maintaining water levels in rivers and lakes. Thus, the impact of extended drought conditions on the entire hydrologic cycle needs to be well understood to guide future resource and land management decisions. This study aims to explore the impact of extended drought conditions on groundwater resources in a representative Iowa watershed using Regional Climate Model scenarios implemented through HydroGeoSphere, a physically-based, surface water-groundwater model. Estimating the impacts of climate changes on groundwater resources requires representation of the full hydrological system, i.e. the connection between the atmospheric and surface-subsurface processes, in a realistic way. In the HydroGeoSphere model, surface and subsurface flow equations are solved simultaneously, and the interdependence of processes like actual evapotranspiration and recharge is handled explicitly. Using such state-of-the-art modeling tools, we seek to address the consequences of changing climate extremes (that have already been experienced and expected to continue over long periods in the future) on the hydrologic cycle of our pilot study area, the South Fork watershed in north-central Iowa. The results will provide a baseline for investigating mitigation strategies in agricultural practices and water use due to changes in the wet and dry cycles of the regional hydrologic cycle.

  4. Bonamia exitiosa transmission among, and incidence in, Asian oyster Crassostrea ariakensis under warm euhaline conditions.

    PubMed

    Audemard, C; Carnegie, R B; Hill, K M; Peterson, C H; Burreson, E M

    2014-07-24

    Previously reported in Australia, New Zealand, and more recently in Europe, the protistan parasite Bonamia exitiosa was also reported in the mid-Atlantic region of the USA after causing serious mortalities there in the Asian oyster Crassostrea ariakensis. At the time, this oyster was being considered for introduction, and the potential consequences of introducing this species were being assessed using field and laboratory studies. B. exitiosa emerged as the most serious disease threat for this oyster species, especially under warm euhaline conditions and for oysters <50 mm in size. To better evaluate how quickly this parasite may be able to spread among C. ariakensis, we investigated B. exitiosa transmission and incidence in C. ariakensis. During a first trial, potential direct transmission of B. exitiosa was evaluated by cohabitating infected C. ariakensis with uninfected C. ariakensis under in vivo quarantine conditions. In a second experiment, B. exitiosa incidence was estimated in situ by determining its prevalence in C. ariakensis deployed in an enzootic area after 4, 7, 14, 21 and 28 d of exposure. Results suggest that under warm euhaline conditions B. exitiosa can be transmitted among C. ariakensis without requiring any other parasite source and that parasite incidence may be at least as high as 40% after only 4 d exposure to an enzootic area. These results underscored the severity of the bonamiasis disease threat to C. ariakensis and provided further evidence that efforts to build an aquaculture industry based on C. ariakensis in the eastern USA might have been thwarted by parasitic disease. PMID:25060506

  5. Regional Warming from Aerosol Removal over the United States: Results from a Transient 2010-2050 Climate Simulation

    NASA Technical Reports Server (NTRS)

    Mickley, L. J.; Leibensperger, E. M.; Jacob, D. J.; Rind, D.

    2012-01-01

    We use a general circulation model (NASA Goddard Institute for Space Studies GCM 3) to investigate the regional climate response to removal of aerosols over the United States. We perform a pair of transient 2010e2050 climate simulations following a scenario of increasing greenhouse gas concentrations, with and without aerosols over the United States and with present-day aerosols elsewhere. We find that removing U.S. aerosol significantly enhances the warming from greenhouse gases in a spatial pattern that strongly correlates with that of the aerosol. Warming is nearly negligible outside the United States, but annual mean surface temperatures increase by 0.4e0.6 K in the eastern United States. Temperatures during summer heat waves in the Northeast rise by as much as 1e2 K due to aerosol removal, driven in part by positive feedbacks involving soil moisture and low cloud cover. Reducing U.S. aerosol sources to achieve air quality objectives could thus have significant unintended regional warming consequences.

  6. Climatic warming changes plant photosynthesis and its temperature dependence in a temperate steppe of northern China

    Microsoft Academic Search

    Shuli Niu; Zhixiong Li; Jianyang Xia; Yi Han; Mingyu Wu; Shiqiang Wan

    2008-01-01

    Warming responses of photosynthesis and its temperature dependence in two C3 grass (Agropyron cristatum, Stipa krylovii), one C4 grass (Pennisetum centrasiaticum), and two C3 forb (Artemisia capillaris, Potentilla acaulis) species in a temperate steppe of northern China were investigated in a field experiment. Experimental warming with infrared heater significantly increased daily mean assimilation rate (A) in P. centrasiaticum and A.

  7. Climate Change: Sources of Warming in the Late 20th Century

    E-print Network

    Marsh, Gerald E

    2009-01-01

    The role of the North Atlantic Oscillation, the Pacific Decadal Oscillation, volcanic and other aerosols, as well as the extraordinary solar activity of the late 20th century are discussed in the context of the warming since the mid-1970s. Much of that warming is found to be due to natural causes.

  8. Possible impacts of climatic warming scenarios on water resources in the Saskatchewan River Subbasin, Canada

    Microsoft Academic Search

    Stewart J. Cohen

    1991-01-01

    Regional scale studies of the impacts of global warming scenarios provide a useful mechanism for identifying potential regional sensitivities, data gaps and research needs, and for raising awareness of the global warming issue at the regional level. Thus, a pilot study of water resources in the Saskatchewan River Sub-basin was undertaken in order to provide first-cut estimates of impacts in

  9. Climate Change: Sources of Warming in the Late 20th Century

    E-print Network

    Gerald E. Marsh

    2009-05-28

    The role of the North Atlantic Oscillation, the Pacific Decadal Oscillation, volcanic and other aerosols, as well as the extraordinary solar activity of the late 20th century are discussed in the context of the warming since the mid-1970s. Much of that warming is found to be due to natural causes.

  10. Australia, the United States, and Global Warming Attached is a letter that I received from Martin Parkinson, Secretary, Department of Climate

    E-print Network

    Hansen, James E.

    1 Australia, the United States, and Global Warming Attached is a letter that I received from Martin Parkinson, Secretary, Department of Climate Change, Government of Australia, and my draft response of Australia Re: Australia's Response to Climate Change Dear Secretary Parkinson: Thank you for your letter

  11. Stomatal Oscillations in Orange Trees under Natural Climatic Conditions

    PubMed Central

    STEPPE, KATHY; DZIKITI, SEBINASI; LEMEUR, RAOUL; MILFORD, JAMES R.

    2006-01-01

    • Background and Aims Stomatal oscillations have been reported in many plant species, but they are usually induced by sudden step changes in the environment when plants are grown under constant conditions. This study shows that in navel orange trees (Citrus sinensis) pronounced stomatal oscillations occur and persist under natural climatic conditions. • Methods Oscillations in stomatal conductance were measured, and related to simultaneous measurements of leaf water potential, and flow rate of sap in the stems of young, potted plants. Cycling was also observed in soil-grown, mature orchard trees, as indicated by sap flow in stem and branches. • Key Results Oscillations in stomatal conductance were caused by the rapid propagation and synchronization of changes in xylem water potential throughout the tree, without rapid changes in atmospheric conditions. • Conclusions The results show marked stomatal oscillations persisting under natural climatic conditions and underscore the need to discover why this phenomenon is so pronounced in orange trees. PMID:16478765

  12. State of the climate in 2010

    E-print Network

    Ganesan, Anita

    Several large-scale climate patterns influenced climate conditions and weather patterns across the globe during 2010. The transition from a warm El Niño phase at the beginning of the year to a cool La Niña phase by July ...

  13. Possible land cover change feedbacks to surface albedo and net radiation over Siberia in a warming climate

    NASA Astrophysics Data System (ADS)

    Tchebakova, N.; Parfenova, E.; Soja, A. J.

    2009-12-01

    Our goal was to simulate vegetation cover and hot spots of vegetation change in the changing climate of Siberia by the end of the 21st century and to insight regarding vegetation change feedbacks on the alteration of surface albedo and energy. We applied the Siberian BioClimatic Model (SiBCliM) to the HadCM3 A2 (with the highest temperature increase) and B1 (with the lowest temperature increase) scenarios of the Hadley Centre (IPCC, 2007) to highlight possible vegetation change. SiBCliM predicts a biome (a zonal vegetation class) from three climatic indices (growing degree-days, negative degree-days, and an annual moisture index) and permafrost. Large changes in land cover are predicted from the A2 scenario: coverage by northern vegetation types (tundra, forest-tundra, and taiga) would decrease from 70 to some 30% enabling southern habitats (forest-steppe, steppe and semidesert) to expand coverage from 30 to 70%. Altered land cover would feedback to the climate system resulting in a potential non-linear response to changes in climate. We investigated the effects of land cover change on surface reflectivity (albedo) resulting in net radiation alterations. We calculated annual albedo as the mean of summer albedo during months with no snow cover and winter albedo during months with snow cover. Snow cover appearance and dissappearance were related to surface temperature thresholds 0, 3 and 5 Celsius degrees. Albedo change by 2080 was calculated as the differences between albedo ascribed to each pixel (between 60oE -140oE and 50oN -75oN) according to a vegetation type and snow cover presence/absence in the current and the 2080 climates. In a warmed climate, by 2080, albedo would increase in the southern and middle latitudes in Siberia due to the forest retreat. In the northern latitudes and highlands, tundra would be replaced by the forest with decreased albedo. The total would result in about a 1% albedo increase over the entire area. Under the predicted warmer climate, these calculations suggest that the annual shortwave and consequently net radiation would decrease in 2/3 of the area in the south and would increase in 1/3 of the area in the north resulting in an even greater warming than currently predicted in the high latitudes. Thus, the regional effects of land cover change on climate would be non-linear. This land change projection suggests that the interactive biosphere should be included in global and regional circulation models to get more reliable projections.

  14. Attribution of soil moisture dynamics - Initial conditions vs. atmospheric forcing and the role of climate change

    NASA Astrophysics Data System (ADS)

    Orth, Rene; Seneviratne, Sonia I.

    2014-05-01

    The world's climate has started to change more quickly in recent decades and a stronger and faster shift is expected in the future. Even if the public perception is mostly limited to a widespread warming, climate change is a complex phenomenon impacting numerous variables of the climate system in different ways, also depending on time and location. Furthermore, extreme events may change more drastically than the mean climate. There is growing evidence that climate change is mostly man-made. However, it is still a matter of debate to which extent changes of the mean climate but also of particular (extreme) events are due to human impact. These questions are addressed by the growing science of climate attribution. Pointing out the anthropogenic influence on extreme events such as the 2010 Russian heatwave or the 2002 floods in Central Europe may help to support adaptation to climate change. This study investigates soil moisture in Europe in the context of climate change, because of its role as a key variable of the land-climate system and its practical importance for instance to agriculture. To derive soil moisture dynamics from 1984-2007 we use E-OBS forcing data together with SRB radiation data and employ an observation-based approach where soil moisture is computed from a water balance equation in which runoff (normalized with precipitation) and ET (normalized with net radiation) are simple functions of soil moisture. The constant runoff function is prescribed for the whole continent, and the ET function is calibrated using temperature data. After performing a validation of the inferred soil moisture data we use it in order to analyze changes in the likelihood of droughts. Our results show increased drought risk especially in north-eastern Europe and the Mediterranean, whereby the probability of extreme droughts increases stronger as for mild dryness episodes. To assess the potential for drought forecasting we furthermore study the importance of the initial conditions versus the atmospheric forcing for monthly soil moisture variations. We find that initial soil moisture anomalies are overall more important than the forcing, even if less pronounced in summer. Especially in southern Europe we show high drought forecasting potential, whereas the forcing is more important in Central and North-eastern Europe.

  15. Global Climate Highlights and Anomalies

    NSDL National Science Digital Library

    NOAA's Global Climate Highlights and Anomalies page offers weekly summaries of global climate highlights and anomalies (warm, cold, wet, dry). Areas experiencing climate anomalies are color-marked on a global map, followed by written summaries of each region's climate conditions. All weeks are posted for the year 2000 (to present), and a link points users to the complete 1999 archive.

  16. Climate Change,Wildlife and Wildlands:A Toolkit for Formal and Informal Educators www.globalchange.gov/climate-toolkit The warm temperatures, beautiful clear waters, and bountiful

    E-print Network

    the Caribbean Sea, the Gulf of Mexico, and part of the Atlantic Ocean. Most of the Caribbean experiences hot and humid weather with heavy rain all year round. During certain times of year, the low-pressure zones, the coastal shelves and warm tropical waters of the Caribbean create perfect conditions for coral reefs. Coral

  17. Effects of pre-cooling procedures on intermittent-sprint exercise performance in warm conditions.

    PubMed

    Duffield, Rob; Marino, Frank E

    2007-08-01

    The aim of this study was to determine whether pre-cooling procedures improve both maximal sprint and sub-maximal work during intermittent-sprint exercise. Nine male rugby players performed a familiarisation session and three testing sessions of a 2 x 30-min intermittent sprint protocol, which consisted of a 15-m sprint every min separated by free-paced hard-running, jogging and walking in 32 degrees C and 30% humidity. The three sessions included a control condition, Ice-vest condition and Ice-bath/Ice-vest condition, with respective cooling interventions imposed for 15-min pre-exercise and 10-min at half-time. Performance measures of sprint time and % decline and distance covered during sub-maximal exercise were recorded, while physiological measures of core temperature (T (core)), mean skin temperature (T (skin)), heart rate, heat storage, nude mass, rate of perceived exertion, rate of thermal comfort and capillary blood measures of lactate [La(-)], pH, Sodium (Na(+)) and Potassium (K(+)) were recorded. Results for exercise performance indicated no significant differences between conditions for the time or % decline in 15-m sprint efforts or the distance covered during sub-maximal work bouts; however, large effect size data indicated a greater distance covered during hard running following Ice-bath cooling. Further, lowered T (core), T (skin), heart rate, sweat loss and thermal comfort following Ice-bath cooling than Ice-vest or Control conditions were present, with no differences present in capillary blood measures of [La(-)], pH, K(+) or Na(+). As such, the ergogenic benefits of effective pre-cooling procedures in warm conditions for team-sports may be predominantly evident during sub-maximal bouts of exercise. PMID:17476523

  18. Forecasting conditional climate-change using a hybrid approach

    USGS Publications Warehouse

    Esfahani, Akbar Akbari; Friedel, Michael J.

    2014-01-01

    A novel approach is proposed to forecast the likelihood of climate-change across spatial landscape gradients. This hybrid approach involves reconstructing past precipitation and temperature using the self-organizing map technique; determining quantile trends in the climate-change variables by quantile regression modeling; and computing conditional forecasts of climate-change variables based on self-similarity in quantile trends using the fractionally differenced auto-regressive integrated moving average technique. The proposed modeling approach is applied to states (Arizona, California, Colorado, Nevada, New Mexico, and Utah) in the southwestern U.S., where conditional forecasts of climate-change variables are evaluated against recent (2012) observations, evaluated at a future time period (2030), and evaluated as future trends (2009–2059). These results have broad economic, political, and social implications because they quantify uncertainty in climate-change forecasts affecting various sectors of society. Another benefit of the proposed hybrid approach is that it can be extended to any spatiotemporal scale providing self-similarity exists.

  19. Role of clouds and land-atmosphere coupling in midlatitude continental summer warm biases and climate change amplification in CMIP5 simulations

    NASA Astrophysics Data System (ADS)

    Cheruy, F.; Dufresne, J. L.; Hourdin, F.; Ducharne, A.

    2014-09-01

    Over land, most state-of-the-art climate models contributing to Coupled Model Intercomparison Project Phase 5 (CMIP5) share a strong summertime warm bias in midlatitude areas, especially in regions where the coupling between soil moisture and atmosphere is effective. The most biased models overestimate solar incoming radiation, because of cloud deficit and have difficulty to sustain evaporation. These deficiencies are also involved in the spread of the summer temperature projections among models in the midlatitude; the models which simulate a higher-than-average warming overestimate the present climate net shortwave radiation which increases more-than-average in the future, in link with a decrease of cloudiness. They also show a higher-than-average reduction of evaporative fraction in areas with soil moisture-limited evaporation regimes. Over these areas, the most biased models in the present climate simulate a larger warming in response to climate change which is likely to be overestimated.

  20. Assessing the Response of Nematode Communities to Climate Change-Driven Warming: A Microcosm Experiment

    PubMed Central

    Gingold, Ruth; Moens, Tom; Rocha-Olivares, Axayácatl

    2013-01-01

    Biodiversity has diminished over the past decades with climate change being among the main responsible factors. One consequence of climate change is the increase in sea surface temperature, which, together with long exposure periods in intertidal areas, may exceed the tolerance level of benthic organisms. Benthic communities may suffer structural changes due to the loss of species or functional groups, putting ecological services at risk. In sandy beaches, free-living marine nematodes usually are the most abundant and diverse group of intertidal meiofauna, playing an important role in the benthic food web. While apparently many functionally similar nematode species co-exist temporally and spatially, experimental results on selected bacterivore species suggest no functional overlap, but rather an idiosyncratic contribution to ecosystem functioning. However, we hypothesize that functional redundancy is more likely to observe when taking into account the entire diversity of natural assemblages. We conducted a microcosm experiment with two natural communities to assess their stress response to elevated temperature. The two communities differed in diversity (high [HD] vs. low [LD]) and environmental origin (harsh vs. moderate conditions). We assessed their stress resistance to the experimental treatment in terms of species and diversity changes, and their function in terms of abundance, biomass, and trophic diversity. According to the Insurance Hypothesis, we hypothesized that the HD community would cope better with the stressful treatment due to species functional overlap, whereas the LD community functioning would benefit from species better adapted to harsh conditions. Our results indicate no evidence of functional redundancy in the studied nematofaunal communities. The species loss was more prominent and size specific in the HD; large predators and omnivores were lost, which may have important consequences for the benthic food web. Yet, we found evidence for alternative diversity–ecosystem functioning relationships, such as the Rivets and the Idiosyncrasy Model. PMID:23825552

  1. Droughts in a warming climate: A global assessment of Standardized precipitation index (SPI) and Reconnaissance drought index (RDI)

    NASA Astrophysics Data System (ADS)

    Asadi Zarch, Mohammad Amin; Sivakumar, Bellie; Sharma, Ashish

    2015-07-01

    Both drought and aridity indicate imbalance in water availability. While drought is a natural temporal hazard, aridity is a constant climatic feature. This paper investigates the changes in drought characteristics across different aridity zones with and without consideration of potential evapotranspiration (PET), as a means to better assess drought in a warming climate. Two drought indexes are employed: (1) Standardized precipitation index (SPI), which is solely based on precipitation; and (2) Reconnaissance drought index (RDI), which, in addition to precipitation, takes PET into account. The two indexes are first employed to observed precipitation and PET data for the period 1960-2009 from the CRU (Climate Research Unit, University of East Anglia) TS 3.1 database. The results indicate that although all the aridity zones experience both downward and upward drought trends, no significant trend is found over large parts of the zones. However, the agreement between SPI and RDI reduces from the hyper-arid zone on one extreme toward the humid zone on the other. In the three more humid zones (i.e. semi-arid, sub-humid, and humid), the indexes exhibit different trends, with RDI showing more decreasing trends (i.e. becoming drier). While SPI generally shows more drought prone areas than RDI for the pre-1998 period, the opposite is observed for the post-1998 period. Given the known changes to PET in observed records, and also expected increases as global warming intensifies, these results suggest that RDI will be consistently different to the SPI as global warming intensifies. This hypothesis is further tested for historic and future climate projections from the CSIRO (Commonwealth Scientific and Industrial Research Organisation, Australia) Mk3.6 global climate model (GCM), with use of the fifth phase of the Coupled Model Intercomparison Project (CMIP5) and RCP8.5 (Representative Concentration Pathways). In this case, PET is calculated using FAO56-PM model for assessment of RDI. The results suggest that agreement between SPI and RDI is affected and decreases remarkably over time (between 1850 and 2100). All these lead to the conclusion that, in the face of climate change, PET, an important component in the hydrologic cycle, should not be ignored in drought modeling.

  2. Quantifying the methane atmospheric concentration during the warm and wet climate of the Middle Miocene Climatic Optimum (17-15 Ma)

    NASA Astrophysics Data System (ADS)

    Ramstein, G.; Hopcroft, P.; Ringeval, B.; Hamon, N.

    2012-04-01

    The warm periods, as the Cenomanian, the Eocene or the Middle Miocene correspond almost always to a very weak Equator to Pole thermal gradient. Recent studies demonstrate that it was possible to simulate the Middle Miocene climate (17-15 Ma) using atmospheric CO2 around 2 PAL (1PAL = 280 ppm) (Krapp and Jungclaus, 2011; Hamon et al., accepted). However, these estimates are in disagreement with the reconstructions from marine sediments (13C, Bore) that suggest a much lower atmospheric CO2 (Pagani et al., 1999; Hendericks and Pagani, 2007; Pearson and Palmer, 2000). Here we investigate an alternative view which is to explore and quantify the methane concentration in the atmosphere. In fact, during the warm and wet climate of the Middle Miocene Climatic Optimum (MMCO), the sources of methane could have been much larger than during the preindustrial period and could have lead to larger concentrations that the one commonly used to perform the MMCO modelling experiments. To get a first order value of the change in methane sources in such a climate, we perform a realistic MMCO experiment using coupled atmosphere-ocean general circulation model (FOAM). Sensitivity tests on the CO2 concentration have been performed. Then we use the simulated climate fields to drive a global vegetation model (SDVGM) and simulate the wetland methane emissions. The key question is therefore: Is it possible that methane plays a role and explains the apparent disagreement between the low value of CO2 as described by the data and the high radiative forcing necessary in the model to explain the vegetation distribution reconstructed by pollen data and megafloras?

  3. Warmly Debated: The Little Ice Age and the Construction of Historical Climatic Regimes, 1650-1950 

    E-print Network

    Gilson, Christopher R.

    2011-08-08

    Climatic change has been the subject of investigation and spirited debate for more than three centuries. One important element of this debate has been the search for and definition of unique, impermanent climatic regimes measurable by historic time...

  4. Improving mitochondrial bioenergetics under ischemic conditions increases warm ischemia tolerance in the kidney.

    PubMed

    Szeto, Hazel H; Liu, Shaoyi; Soong, Yi; Birk, Alexander V

    2015-01-01

    Ischemia time during partial nephrectomy is strongly associated with acute and chronic renal injury. ATP depletion during warm ischemia inhibits ATP-dependent processes, resulting in cell swelling, cytoskeletal breakdown, and cell death. The duration of ischemia tolerated by the kidney depends on the amount of ATP that can be produced with residual substrates and oxygen in the tissue to sustain cell function. We previously reported that the rat can tolerate 30-min ischemia quite well but 45-min ischemia results in acute kidney injury and progressive interstitial fibrosis. Here, we report that pretreatment with SS-20 30 min before warm ischemia in the rat increased ischemia tolerance from 30 to 45 min. Histological examination of kidney tissues revealed that SS-20 reduced cytoskeletal breakdown and cell swelling after 45-min ischemia. Electron microscopy showed that SS-20 reduced mitochondrial matrix swelling and preserved cristae membranes, suggesting that SS-20 enhanced mitochondrial ATP synthesis under ischemic conditions. Studies with isolated kidney mitochondria showed dramatic reduction in state 3 respiration and respiratory control ratio after 45-min ischemia, and this was significantly improved by SS-20 treatment. These results suggest that SS-20 increases efficiency of the electron transport chain and improves coupling of oxidative phosphorylation. SS-20 treatment after ischemia also significantly reduced interstitial fibrosis. These new findings reveal that enhancing mitochondrial bioenergetics may be an important target for improving ischemia tolerance, and SS-20 may serve well for minimizing acute kidney injury and chronic kidney disease following surgical procedures such as partial nephrectomy and transplantation. PMID:25339695

  5. Climatic and environmental conditions favoring the crossing of the Carpathians by early Neolithic populations

    NASA Astrophysics Data System (ADS)

    Per?oiu, Ioana; Per?oiu, Aurel

    2015-04-01

    The study of the origin and spread of Neolithic has been the subject of heated debate since the early studies of Childe (1942). To what extent the dispersal process was influenced by environmental factors is still debated, one of the issues being whether climatic conditions influencing agricultural practices, could have influenced the dispersal route, "blocking" some of the Neolithic societies in front of ecological barriers. Data from Neolithic sites in SE Europe shows that a continuous stream of people and cultures flowed through the Danube's Iron Gates towards Central Europe, while in the eastern part of Europe this process was delayed, people and cultures "moving" around the Carpathians and crossing them with a delay of ca. 1000 years. One of the possible avenues for this crossing is the floodplain of Some?u Mic River (Transylvanian depression), home to the oldest (~8500 cal. BP) Neolithic settlement in Romania. In this paper, we review the climatic and environmental changes that affected the region at the time of Neolithic dispersal. Pollen and stable isotopes in cave ice indicate an early Holocene rapid warming during summer months, peaking around 7 ka cal. BP; and a delayed warming for autumn and winter months, peaking at 5 ka cal. BP, both followed by a continuous cooling trend towards the present. Some?u Mic River developed and maintained a narrow sinuous channel during the Holocene, with local development of meanders and anabranches, in response to both climatic and geologic controlling factors. Archaeological finds in the floodplain and the lower terraces suggest that human societies in the region responded in sensitive manner to these climatic and environmental changes. During warm and dry periods, with low fluvial activity, the number of settlements increased in the floodplain's perimeter, while during the short cold and humid periods, the number of settlements rapidly increased on the lower terraces and on the valley slopes, disappearing from the flooded valley bottom and flash-flood prone alluvial fans. Our results suggest that once reaching the foothills of the Carpathian Mts., early Neolithic communities encountered a forested landscape and rather than clearing it for agriculture, they have moved along the middle Danube towards Pannonia and Central Europe, as well as along the lower reaches of the Danube's tributaries, following the most suitable and easily accessible terrain for agriculture practices.

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

    E-print Network

    Drange, Helge

    of climate and climate change is fundamentally concerned with two things: a well-defined and sufficiently and relatively simple diagnostic relation to quantify the change in ocean circulation consistent with reconstructed ocean temperatures. It is found that maritime climate and the strength of the Norwegian Atlantic

  7. Features of the ocean-atmosphere exchange and its effect on terrestrial climate conditions

    NASA Astrophysics Data System (ADS)

    Kartushinsky, A.; Sashko, L.

    The climatic changes on Earth are to a large extent influenced by the intensity of ocean-atmosphere-land interactions Energy exchange in the atmosphere-ocean system depends on the transfer of warm and cold water masses by stream flows Interaction of water masses leads to formation of frontal zones with high temperature gradients Such zones are easily detected by temperature gradients which are calculated according to AVHRR MCSST satellite data for the 1982 -- 1986 average monthly and 1990 -- 2001 average weekly periods The spatial extension and the size of the frontal zone formed by Gulf Stream in North Atlantic affects the evaporation mode Such interaction with atmosphere leads to changes in the cyclonic and anticyclonic activity in the North Atlantic Oscillation NAO zone In this work the seasonal North Atlantic Oscillations are compared with the temperature gradients in North Atlantic for the period of satellite measurements Besides the investigation is made of the connection between the changes of NAO and climatic parameters overland We used the weather stations data concerning the average monthly air temperature and precipitation for the territory of Eurasia for the period of 1900-2004 This work analyses the features of ocean-atmosphere interaction and the effect of such interaction on the climatic conditions We developed software for the analysis of climagrams in graphic form in which the air temperature and amount of precipitation are averaged over the whole observation period and also for separate periods The average seasonal

  8. A Study on Warm Hydroforming of Al and Mg Sheet Materials: Mechanism and Proper Temperature Conditions

    Microsoft Academic Search

    Ho Choi; Muammer Koç; Jun Ni

    2008-01-01

    Hydroforming of lightweight materials at elevated temperature is a relatively new process with promises of increased formability at low internal pressure levels. In this study, the mechanism of warm hydroforming processes is presented in terms of its formability by comparison with warm forming, and cold hydroforming processes. Additionally, a strat- egy is proposed to control process parameters, such as temperature,

  9. Premonsoon Aerosol Characterization and Radiative Effects Over the Indo-Gangetic Plains: Implications for Regional Climate Warming

    NASA Technical Reports Server (NTRS)

    Gautam, Ritesh; Hsu, N. Christina; Lau, K.-M.

    2010-01-01

    The Himalayas have a profound effect on the South Asian climate and the regional hydrological cycle, as it forms a barrier for the strong monsoon winds and serves as an elevated heat source, thus controlling the onset and distribution of precipitation during the Indian summer monsoon. Recent studies have suggested that radiative heating by absorbing aerosols, such as dust and black carbon over the Indo-Gangetic Plains (IGP) and slopes of the Himalayas, may significantly accelerate the seasonal warming of the Hindu Kush-Himalayas-Tibetan Plateau (HKHT) and influence the subsequent evolution of the summer monsoon. This paper presents a detailed characterization of aerosols over the IGP and their radiative effects during the premonsoon season (April-May-June) when dust transport constitutes the bulk of the regional aerosol loading, using ground radiometric and spaceborne observations. During the dust-laden period, there is a strong response of surface shortwave flux to aerosol absorption indicated by the diurnally averaged forcing efficiency of -70 W/sq m per unit optical depth. The simulated aerosol single-scattering albedo, constrained by surface flux and aerosol measurements, is estimated to be 0.89+/- 0.01 (at approx.550 nm) with diurnal mean surface and top-of-atmosphere forcing values ranging from -11 to -79.8 W/sq m and +1.4 to +12 W/sq m, respectively, for the premonsoon period. The model-simulated solar heating rate profile peaks in the lower troposphere with enhanced heating penetrating into the middle troposphere (5-6 km), caused by vertically extended aerosols over the IGP with peak altitude of approx.5 km as indicated by spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization observations. On a long-term climate scale, our analysis, on the basis of microwave satellite measurements of tropospheric temperatures from 1979 to 2007, indicates accelerated annual mean warming rates found over the Himalayan-Hindu Kush region (0.21 C/decade+/-0.08 C/decade) and underscores the potential role of enhanced aerosol solar absorption in the maximum warming localized over the western Himalayas (0.26 C/decade f 0.09 C/decade) that significantly exceed the entire HKHT and global warming rates. We believe the accelerated warming rates reported here are critical to both the South Asian summer monsoon and hydro-glaciological resource variability in the Himalayan-Hindu Kush snowpack and therefore to the densely populated downstream regions.

  10. Examining the potential impact of a warming ocean on food insecure Africa: concerns and mechanisms for abrupt climate change

    NASA Astrophysics Data System (ADS)

    Funk, C.; Dettinger, M.; Verdin, J.

    2007-12-01

    Given that more than 200 million sub-Saharan Africans are food insecure, abrupt climate change in Africa could be devastating. Recent observations for eastern and southern Africa suggest substantial declines in main growing season rainfall over the past 20 years. In this talk we present research from a multi-year study that examined the causes and implications of these drying trends. Our statistical and dynamic modeling results suggest that warming in the Indian Ocean has been linked to increased oceanic convection and disruptions in onshore moisture transports. These moisture transport disruptions, in turn, are probably associated with an increased frequency in agricultural drought in sub-tropical countries along Africa's eastern seaboard. This 'warm ocean-dry Africa' dipole appears to be a major driver of decadal variability. An evaluation of 11 climate change models suggests that increased tropical Indian Ocean precipitation, and the associated moisture transport disruptions, may in fact be anthropogenic, accounting for at least part of the regional drought tendencies in eastern and southern Africa over the past 20 years. These simulations also suggest continued increases in oceanic convection will be very likely over the next century. This diabatic forcing will likely produce continuing rainfall declines across 7 food insecure nations. These drying trends, combined with declining per capita agricultural capacity, are likely to contribute to a ~250 percent increase in food shortages over the next 30 years. Modest agricultural and market development, however, could alleviate the food problem substantially.

  11. Experimental climate warming enforces seed dormancy in South African Proteaceae but seedling drought resilience exceeds summer drought periods.

    PubMed

    Arnolds, Judith L; Musil, Charles F; Rebelo, Anthony G; Krüger, Gert H J

    2015-04-01

    Two hypotheses-that elevated night-time temperatures due to climate warming would enforce post-fire dormancy of Proteaceae seed due to low moisture, and that periods without rain during summer would exceed desiccation periods tolerated by Proteaceae seedlings-were tested empirically. Enforced dormancy, i.e., the inability to germinate due to an environmental restraint, was tested by measuring seed germination in 11 Proteaceae species in experimental mesocosms whose soils were artificially elevated by 1.4 and 3.5 °C above ambient by far-red wavelength filtered infrared lamps. Diminished totality of germination and velocities were observed in 91 and 64%, respectively, of the Proteaceae species tested. Drought resilience was tested in one-year-old seedlings of 16 Proteaceae species by withholding water from potted plants during summer in a greenhouse. The most drought-resilient Proteaceae species displayed the lowest initial transpiration rates at field capacity, the smallest declines in transpiration rate with decreasing soil water content, and the lowest water losses by transpiration. Projected drought periods leading to the complete cessation of transpiration in all Proteaceae species greatly exceeded the number of days without rain per month during summer in the current distribution ranges of those species. It was therefore concluded that enforced seed dormancy induced by elevated night-time temperatures is the post-fire recruitment stage of Proteaceae that is most sensitive to climate warming. PMID:25502439

  12. Predicting the impact of climatic warming on the carbon balance of the moss Sanionia uncinata on a maritime Antarctic island.

    PubMed

    Nakatsubo, Takayuki

    2002-04-01

    The effects of climatic factors, especially those of temperature, on the carbon balance of the moss Sanionia uncinata were examined on King George Island in the maritime Antarctic. Net photosynthesis (P(n)) and dark respiration rates of two colonies (A and B) were measured with a portable infrared gas analyzer. Colony A showed small P(n) compared with its dark respiration rates throughout the growing season. Colony B showed much higher net photosynthetic rates, but the dark respiration rates of the two colonies did not differ significantly. Net photosynthetic rate determined at light saturation was almost constant over a wide temperature range, from 5 degrees to 15 degrees C, while the dark respiration was strongly affected by temperature. To assess the impact of warming on the carbon balance of the moss, cumulative carbon gain of the moss was calculated using a simulation model for the main part of the growing season. The results suggest that climatic warming may cause a reduction of carbon gain in some relatively photosynthetically inactive moss colonies. PMID:12884132

  13. The last glacial maximum climatic conditions on Easter Island

    Microsoft Academic Search

    G. Azizi; J. R. Flenley

    2008-01-01

    The aim of this paper is to refine previous estimates of last glacial maximum (LGM) climatic conditions for Easter Island. Samples were analysed for fossil pollen from the lower half of a 13.40m sediment core (RRA5). This part of the core includes a time span from ca. 28,000–10,000 14C BP. The results show that during this period there were three

  14. Ceramic production during changing environmental/climatic conditions

    NASA Astrophysics Data System (ADS)

    Oestreich, Daniela B.; Glasmacher, Ulrich A.

    2015-04-01

    Ceramics, with regard to their status as largely everlasting everyday object as well as on the basis of their chronological sensitivity, reflect despite their simplicity the technological level of a culture and therefore also, directly or indirectly, the adaptability of a culture with respect to environmental and/or climatic changes. For that reason the question arises, if it is possible to identify changes in production techniques and raw material sources for ceramic production, as a response to environmental change, e.g. climate change. This paper will present results of a research about Paracas Culture (800 - 200 BC), southern Peru. Through several investigations (e.g. Schittek et al., 2014; Eitel and Mächtle, 2009) it is well known that during Paracas period changes in climate and environmental conditions take place. As a consequence, settlement patterns shifted several times through the various stages of Paracas time. Ceramics from three different sites (Jauranga, Cutamalla, Collanco) and temporal phases of the Paracas period are detailed archaeometric, geochemical and mineralogical characterized, e.g. Raman spectroscopy, XRD, and ICP-MS analyses. The aim of this research is to resolve potential differences in the chemical composition of the Paracas ceramics in space and time and to compare the data with the data sets of pre-Columbian environmental conditions. Thus influences of changing environmental conditions on human societies and their cultural conditions will be discussed. References Eitel, B. and Mächtle, B. 2009. Man and Environment in the eastern Atacama Desert (Southern Peru): Holocene climate changes and their impact on pre-Columbian cultures. In: Reindel, M. & Wagner, G. A. (eds.) New Technologies for Archaeology. Berlin Heidelberg: Springer-Verlag. Schittek, K., Mächtle, B., Schäbitz, F., Forbriger, M., Wennrich, V., Reindel, M., and Eitel, B.. Holocene environmental changes in the highlands of the southern Peruvian Andes (14° S) and their impact on pre-Columbian cultures, Clim. Past Discuss., 10, 1707-1746.

  15. Climate warming and the decline of zooplankton in the California current

    SciTech Connect

    Roemmich, D.; McGowan, J. [Univ. of California, San Diego, CA (United States)

    1995-03-03

    Since 1951, the biomass of macrozooplankton in waters off southern California has decreased by 80 percent. During the same period, the surface layer warmed-by more than 1.5{degrees}C in some places-and the temperature differences across the thermocline increased. Increased stratification resulted in less lifting of the thermocline by wind-driven upwelling. A shallower source of upwelled waters provided less inorganic nutrient for new biological production and hence supported a smaller zooplankton population. Continued warming could lead to further decline of zooplankton. 10 refs., 5 figs.

  16. Response to CO2 Transient Increase in the GISS Coupled Model: Regional Coolings in a Warming Climate

    NASA Technical Reports Server (NTRS)

    Russell, Gary L.; Rind, David

    1999-01-01

    The (GISS) Goddard Institute for Space Studies coupled atmosphere-ocean model is used to investigate the effect of increased atmospheric CO2 by comparing a compounded 1 percent CO2 increase experiment with a control simulation. After 70 years of integration, the global surface air temperature in the 1 percent CO2 experiment is 1.43 C warmer. In spite of this global warming, there are two distinct regions, the northern Atlantic Ocean and the southern Pacific Ocean, where the surface air temperature is up to 4 C cooler. This situation is maintained by two positive feedbacks: a local effect on convection in the South Pacific and a non-local impact on the meridional circulation in the North Atlantic. The poleward transport of latent energy and dry static energy by the atmosphere is greater in the 1 percent CO2 experiment, caused by warming and therefore increased water vapor and greater greenhouse capacity at lower latitudes. The larger atmospheric transports tend to reduce upward vertical fluxes of heat and moisture from the ocean surface at high latitudes, which has the effect of stabilizing the ocean, reducing both convection and the thermohaline circulation. With less convection, less warm water is brought up from below, and with a reduced North Atlantic thermohaline circulation (by 30 percent at time of CO2 doubling), the poleward energy transport by the oceans decreases. The colder water then leads to further reductions in evaporation, decreases of salinity at high latitudes, continued stabilization of the ocean, and maintenance of reduced convection and meridional overturning. Although sea ice decreases globally, it increases in the cooling regions which reduces the overall climate sensitivity; its effect is most pronounced in the Southern Hemisphere. Tropical warming has been observed over the past several decades; if modeling studies such as this and others which have produced similar effects are valid, these processes may already be beginning.

  17. Fingerprints of the initial conditions on the density profiles of cold and warm dark matter haloes

    NASA Astrophysics Data System (ADS)

    Polisensky, E.; Ricotti, M.

    2015-06-01

    We use N-body simulations of dark matter haloes in cold dark matter (CDM) and a large set of different warm dark matter (WDM) cosmologies to demonstrate that the spherically averaged density profile of dark matter haloes has a shape that depends on the power spectrum of matter perturbations. Density profiles are steeper in WDM but become shallower at r < 0.01Rvir. Virialization isotropizes the velocity dispersion in the inner regions of the halo but does not erase the memory of the initial conditions in phase space. The location of the observed deviations from CDM in the density profile and in phase space can be directly related to the ratio between the halo mass and the filtering mass and are most evident in small mass haloes, even for a 34 keV thermal relic WDM. The rearrangement of mass within the haloes supports analytic models of halo structure that include angular momentum. We also find evidence of a dependence of the slope of the inner density profile in CDM cosmologies on the halo mass with more massive haloes exhibiting steeper profiles, in agreement with the model predictions and with previous simulation results. Our work complements recent studies of microhaloes near the filtering scale in CDM and strongly argue against a universal shape for the density profile.

  18. Heart Rate Variability in Sleeping Preterm Neonates Exposed to Cool and Warm Thermal Conditions

    PubMed Central

    Stéphan-Blanchard, Erwan; Chardon, Karen; Léké, André; Delanaud, Stéphane; Bach, Véronique; Telliez, Frédéric

    2013-01-01

    Sudden infant death syndrome (SIDS) remains the main cause of postneonatal infant death. Thermal stress is a major risk factor and makes infants more vulnerable to SIDS. Although it has been suggested that thermal stress could lead to SIDS by disrupting autonomic functions, clinical and physiopathological data on this hypothesis are scarce. We evaluated the influence of ambient temperature on autonomic nervous activity during sleep in thirty-four preterm neonates (mean ± SD gestational age: 31.4±1.5 weeks, postmenstrual age: 36.2±0.9 weeks). Heart rate variability was assessed as a function of the sleep stage at three different ambient temperatures (thermoneutrality and warm and cool thermal conditions). An elevated ambient temperature was associated with a higher basal heart rate and lower short- and long-term variability in all sleep stages, together with higher sympathetic activity and lower parasympathetic activity. Our study results showed that modification of the ambient temperature led to significant changes in autonomic nervous system control in sleeping preterm neonates. The latter changes are very similar to those observed in infants at risk of SIDS. Our findings may provide greater insight into the thermally-induced disease mechanisms related to SIDS and may help improve prevention strategies. PMID:23840888

  19. Ecoclimatic indicators to study crop suitability in present and future climatic conditionsTIC CONDITIONS

    NASA Astrophysics Data System (ADS)

    Caubel, Julie; Garcia de Cortazar Atauri, Inaki; Huard, Frédéric; Launay, Marie; Ripoche, Dominique; Gouache, David; Bancal, Marie-Odile; Graux, Anne-Isabelle; De Noblet, Nathalie

    2013-04-01

    Climate change is expected to affect both regional and global food production through changes in overall agroclimatic conditions. It is therefore necessary to develop simple tools of crop suitability diagnosis in a given area so that stakeholders can envisage land use adaptations under climate change conditions. The most common way to investigate potential impacts of climate on the evolution of agrosystems is to make use of an array of agroclimatic indicators, which provide synthetic information derived from climatic variables and calculated within fixed periods (i.e. January first - 31th July). However, the information obtained during these periods does not enable to take account of the plant response to climate. In this work, we present some results of the research program ORACLE (Opportunities and Risks of Agrosystems & forests in response to CLimate, socio-economic and policy changEs in France (and Europe). We proposed a suite of relevant ecoclimatic indicators, based on temperature and rainfall, in order to evaluate crop suitability for both present and new climatic conditions. Ecoclimatic indicators are agroclimatic indicators (e.g., grain heat stress) calculated during specific phenological phases so as to take account of the plant response to climate (e.g., the grain filling period, flowering- harvest). These indicators are linked with the ecophysiological processes they characterize (for e.g., the grain filling). To represent this methodology, we studied the suitability of winter wheat in future climatic conditions through three distinct French sites, Toulouse, Dijon and Versailles. Indicators have been calculated using climatic data from 1950 to 2100 simulated by the global climate model ARPEGE forced by a greenhouse effect corresponding to the SRES A1B scenario. The Quantile-Quantile downscaling method was applied to obtain data for the three locations. Phenological stages (emergence, ear 1 cm, flowering, beginning of grain filling and harvest) have been simulated by the STICS, CERES and PANORAMIX crop models with the same input climatic data. Results showed that phenological stages tend to be reached earlier in the future. Significant differences were noted between indicators calculated for invariable calendar periods and indicators calculated during phenological phases. Therefore, ecoclimatic indicators are relevant to provide accurate information about crop suitability in the context of climate change. Whereas most of the indicators do not indicate any significant changes in the future, plant mortality due to frost risks from emergence to ear 1 cm tends to decrease and water supply tends to be more limiting in the future. These indicators do not replace models but represent additional tools for understanding and spatializing some results obtained by models. Their use can provide a spatial distribution of crops according to their suitability in present or future climatic conditions and enable us to minimize the risk of crop failure. It would be interesting to consider the response uncertainties according to the uncertainties we have in future climatic predictions by using different greenhouse emission scenarios and downscaling methods.

  20. Agricultural pests under future climate conditions: downscaling of regional climate scenarios with a stochastic weather generator

    NASA Astrophysics Data System (ADS)

    Hirschi, M.; Stöckli, S.; Dubrovsky, M.; Spirig, C.; Rotach, M. W.; Calanca, P.; Samietz, J.

    2010-09-01

    As a consequence of current and projected climate change in temperate regions of Europe, agricultural pests and diseases are expected to occur more frequently and possibly to extend to previously unaffected regions. Given their economic and ecological relevance, detailed forecasting tools for various pests have been developed, which model the infestation depending on actual weather conditions. Assessing the future risk of pest-related damages therefore requires future weather data at high temporal and spatial resolution. In particular, pest forecast models are often not based on screen temperature and precipitation alone (i.e., the most generally projected climate variables), but might require input variables such as soil temperature, in-canopy net radiation or leaf wetness. Here, we use a stochastic weather and a re-sampling procedure for producing site-specific hourly weather data from regional climate change scenarios for 2050 in Switzerland. The climate change scenarios were derived from multi-model projections and provide probabilistic information on future regional changes in temperature and precipitation. Hourly temperature, precipitation and radiation data were produced by first generating daily weather data for these climate scenarios and then using a nearest neighbor re-sampling approach for creating realistic diurnal cycles. These hourly weather time series were then used for modeling important phases in the lifecycle of codling moth, the major insect pest in apple orchards worldwide. First results indicate a shift in the occurrence and duration of phases relevant for pest disease control for projected as compared to current climate (e.g. the flight of the codling moth starts about ten days earlier in future climate), continuing an already observed trend towards more favorable conditions for this insect during the last 20 years.

  1. Global Warming: Is There Still Time to Avoid

    E-print Network

    Hansen, James E.

    Global Warming: Is There Still Time to Avoid Disastrous Human -Made Climate Change? i.e. Have We simulations. (B) Simulated and observed surface temperature change. #12;21st Century Global Warming Climate) Simulated Global Warming Warming

  2. Can phenological models predict tree phenology accurately under climate change conditions?

    NASA Astrophysics Data System (ADS)

    Chuine, Isabelle; Bonhomme, Marc; Legave, Jean Michel; García de Cortázar-Atauri, Inaki; Charrier, Guillaume; Lacointe, André; Améglio, Thierry

    2014-05-01

    The onset of the growing season of trees has been globally earlier by 2.3 days/decade during the last 50 years because of global warming and this trend is predicted to continue according to climate forecast. The effect of temperature on plant phenology is however not linear because temperature has a dual effect on bud development. On one hand, low temperatures are necessary to break bud dormancy, and on the other hand higher temperatures are necessary to promote bud cells growth afterwards. Increasing phenological changes in temperate woody species have strong impacts on forest trees distribution and productivity, as well as crops cultivation areas. Accurate predictions of trees phenology are therefore a prerequisite to understand and foresee the impacts of climate change on forests and agrosystems. Different process-based models have been developed in the last two decades to predict the date of budburst or flowering of woody species. They are two main families: (1) one-phase models which consider only the ecodormancy phase and make the assumption that endodormancy is always broken before adequate climatic conditions for cell growth occur; and (2) two-phase models which consider both the endodormancy and ecodormancy phases and predict a date of dormancy break which varies from year to year. So far, one-phase models have been able to predict accurately tree bud break and flowering under historical climate. However, because they do not consider what happens prior to ecodormancy, and especially the possible negative effect of winter temperature warming on dormancy break, it seems unlikely that they can provide accurate predictions in future climate conditions. It is indeed well known that a lack of low temperature results in abnormal pattern of bud break and development in temperate fruit trees. An accurate modelling of the dormancy break date has thus become a major issue in phenology modelling. Two-phases phenological models predict that global warming should delay or compromise dormancy break at the species equatorward range limits leading to a delay or even impossibility to flower or set new leaves. These models are classically parameterized with flowering or budburst dates only, with no information on the dormancy break date because this information is very scarce. We evaluated the efficiency of a set of process-based phenological models to accurately predict the dormancy break dates of four fruit trees. Our results show that models calibrated solely with flowering or budburst dates do not accurately predict the dormancy break date. Providing dormancy break date for the model parameterization results in much more accurate simulation of this latter, with however a higher error than that on flowering or bud break dates. But most importantly, we show also that models not calibrated with dormancy break dates can generate significant differences in forecasted flowering or bud break dates when using climate scenarios. Our results claim for the urgent need of massive measurements of dormancy break dates in forest and fruit trees to yield more robust projections of phenological changes in a near future.

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

    Microsoft Academic Search

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

    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

  4. Climate of Concern--A Search for Effective Strategies for Teaching Children about Global Warming

    ERIC Educational Resources Information Center

    Taber, Fiona; Taylor, Neil

    2009-01-01

    Recent research suggests that the issue of global warming is one of great concern for Australian children. This point to the need for effective teaching about this issue. Children should be properly informed about actions that help reduce carbon emissions as this may give them a sense of empowerment and go some way to alleviating concerns. This…

  5. Estimates of future warming-induced methane emissions from hydrate offshore west Svalbard for a range of climate models

    NASA Astrophysics Data System (ADS)

    Marín-Moreno, Héctor; Minshull, Timothy A.; Westbrook, Graham K.; Sinha, Bablu

    2015-05-01

    Methane hydrate close to the hydrate stability limit in seafloor sediment could represent an important source of methane to the oceans and atmosphere as the oceans warm. We investigate the extent to which patterns of past and future ocean-temperature fluctuations influence hydrate stability in a region offshore West Svalbard where active gas venting has been observed. We model the transient behavior of the gas hydrate stability zone at 400-500 m water depth (mwd) in response to past temperature changes inferred from historical measurements and proxy data and we model future changes predicted by seven climate models and two climate-forcing scenarios (Representative Concentration Pathways RCPs 2.6 and 8.5). We show that over the past 2000 year, a combination of annual and decadal temperature fluctuations could have triggered multiple hydrate-sourced methane emissions from seabed shallower than 400 mwd during episodes when the multidecadal average temperature was similar to that over the last century (˜2.6°C). These temperature fluctuations can explain current methane emissions at 400 mwd, but decades to centuries of ocean warming are required to generate emissions in water deeper than 420 m. In the venting area, future methane emissions are relatively insensitive to the choice of climate model and RCP scenario until 2050 year, but are more sensitive to the RCP scenario after 2050 year. By 2100 CE, we estimate an ocean uptake of 97-1050 TgC from marine Arctic hydrate-sourced methane emissions, which is 0.06-0.67% of the ocean uptake from anthropogenic CO2 emissions for the period 1750-2011.

  6. Paleoclimate. Synchronization of North Pacific and Greenland climates preceded abrupt deglacial warming.

    PubMed

    Praetorius, Summer K; Mix, Alan C

    2014-07-25

    Some proposed mechanisms for transmission of major climate change events between the North Pacific and North Atlantic predict opposing patterns of variations; others suggest synchronization. Resolving this conflict has implications for regulation of poleward heat transport and global climate change. New multidecadal-resolution foraminiferal oxygen isotope records from the Gulf of Alaska (GOA) reveal sudden shifts between intervals of synchroneity and asynchroneity with the North Greenland Ice Core Project (NGRIP) ?(18)O record over the past 18,000 years. Synchronization of these regions occurred 15,500 to 11,000 years ago, just prior to and throughout the most abrupt climate transitions of the last 20,000 years, suggesting that dynamic coupling of North Pacific and North Atlantic climates may lead to critical transitions in Earth's climate system. PMID:25061208

  7. Evolution of non-uniformly seeded warm clouds in idealized turbulent conditions This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-print Network

    Falkovich, Gregory

    Evolution of non-uniformly seeded warm clouds in idealized turbulent conditions This article has of non-uniformly seeded warm clouds in idealized turbulent conditions Stanislav Derevyanko1,3 , Gregory seeding of maritime clouds [5, 6]. Secondly, it is often desirable to postpone rain, for instance

  8. The Role Of Oceanic Plateau Volcanism On Climate Change: Warming And Cooling Episodes Across Early Aptian Oceanic Anoxic Event 1a

    NASA Astrophysics Data System (ADS)

    Bottini, C.; Erba, E.; Mutterlose, J.

    2011-12-01

    The early Aptian is marked by a global phenomenon of organic matter burial in oxygen-depleted oceans known as Oceanic Anoxic Event 1a (OAE 1a: ~120 Ma). Volcanism associated with the emplacement of the Ontong Java Plateau (OJP) is thought to be the main triggering mechanism for global anoxia, ocean acidification and greenhouse conditions. However, climate instability during OAE 1a is indicated by independent studies on TEX86, sporomorphs and oxygen-stable isotope but a direct connection between OJP volcanic phases and temperature variations has not been ascertained. A high-resolution integrated nannofossil-geochemical investigation of distant sections from the Tethys, the Pacific Ocean and the Boreal Realm has revealed systematic and synchronous changes. Specifically, the nannofossil Temperature Index and Os-isotope records allowed the reconstruction of a complex series of global warming and cooling events across OAE 1a and their relationships with OJP volcanism as well as weathering patterns. Two prominent volcanic phases are documented in the Os-isotope records: the first preceding OAE 1a and the second one, of major intensity, starting in the core of the negative C-isotopic anomaly. Both phases are paralleled by increased temperature, suggestive of a (super)greenhouse climate triggered by excess volcanogenic CO2. Indeed, our data indicate that the beginning of the prolonged volcanic phase during OAE 1a coincides with warmest temperatures. In the early part of OAE 1a, between the two major volcanic phases, there is a ~100 kyrs-long interval characterized by a radiogenic Os-isotope peak, suggestive of accelerated continental weathering rates, with or without volcanism cessation, following an interval of abrupt warming and preceding a cooling interlude. Arguably, warming at OAE 1a onset promoted methane hydrate dissociation (also suggested by C-isotope and biomarkers analyses), which was perhaps instrumental in triggering continental weathering. Subsequent CO2 draw down, possibly during OJP quiescence, might explain the brief cooling interlude annihilated by warmest temperatures coeval with the onset of OJP paroxysmal phase. In the second part of OAE 1a two more cooling events sandwich an interval of intermediate and fluctuating temperatures. The three cooling episodes correlate with high TOC content, suggesting that burial of organic matter acted as storage of excess CO2, thus temporarily mitigating greenhouse conditions, although under persisting OJP activity. The end of OAE 1a corresponds to the vanishing of OJP volcanism as recorded by Os-isotope. A major cooling episode decrees the conclusion of greenhouse conditions for the rest of the Aptian. Increasing data and improved chronology show that volcanism of gigantic plateaus such as OJP is qualified to cause severe global warming and also indirectly to impact temperature changes. In fact, positive and negative feedbacks vicariously governed by prolonged (and possibly pulsing) formation of oceanic plateaus may be likewise or even more influential in controlling climate variability.

  9. The Synergistic Relationship of Climate Change and Natural variability in Consideration of Dynamically Downscaled Warm Season Climate Projections in North America

    NASA Astrophysics Data System (ADS)

    Chang, H.; Castro, C. L.; Dominguez, F.; Monson, R. K.

    2012-12-01

    The prediction of warm season North American monsoon (NAM) precipitation has been a daunting task due to both large scale and local forcing mechanisms in Southwest U.S. and Mexico, such as SST interannual variability and large scale atmospheric teleconnections, moisture transport and impact of complex terrain. The observational record has shown a 'wet gets wetter and dry gets drier' global monsoon precipitation trend. We hypothesize that the increase in warm season precipitation extremes in North American will be further enhanced with natural variability. Two sets of regional climate projections have been created using the Weather Research and Forecast (WRF) model driven by two dynamically downscaled IPCC AR4 data (MPI-ECHAM5 and UKMO-HadCM3), which have a good representation of Southwest U.S. climatology and interannual variability. The statistically significant dominant early summer (June/July) precipitation modes were first identified using empirical orthogonal function (EOF) analysis. Both WRF-IPCC simulations have a similar dominant mode of precipitation variability as compared to observational record in the 20th century. Extreme temperature and precipitation anomalies between mid 20th century and early 21st century are grouped according to Pacific SST variability. The long-term free-running RCM simulations are dependent on the driving large scale circulation from the GCMs, as spectral nudging is utilized in the simulations. Although both IPCC GCMs used have a good ability to represent the historical regional scale climatology, WRF-MPI is shown to have a more realistic climate projection in the 21st century when compared with the trends in the recent observational record of the past sixty years. Our extreme event analyses show that both temperature and precipitation extremes synergistically interact with natural climate variability.

  10. Diverging Responses of Tropical Andean Biomes under Future Climate Conditions

    PubMed Central

    Tovar, Carolina; Arnillas, Carlos Alberto; Cuesta, Francisco; Buytaert, Wouter

    2013-01-01

    Observations and projections for mountain regions show a strong tendency towards upslope displacement of their biomes under future climate conditions. Because of their climatic and topographic heterogeneity, a more complex response is expected for biodiversity hotspots such as tropical mountain regions. This study analyzes potential changes in the distribution of biomes in the Tropical Andes and identifies target areas for conservation. Biome distribution models were developed using logistic regressions. These models were then coupled to an ensemble of 8 global climate models to project future distribution of the Andean biomes and their uncertainties. We analysed projected changes in extent and elevational range and identified regions most prone to change. Our results show a heterogeneous response to climate change. Although the wetter biomes exhibit an upslope displacement of both the upper and the lower boundaries as expected, most dry biomes tend to show downslope expansion. Despite important losses being projected for several biomes, projections suggest that between 74.8% and 83.1% of the current total Tropical Andes will remain stable, depending on the emission scenario and time horizon. Between 3.3% and 7.6% of the study area is projected to change, mostly towards an increase in vertical structure. For the remaining area (13.1%–17.4%), there is no agreement between model projections. These results challenge the common believe that climate change will lead to an upslope displacement of biome boundaries in mountain regions. Instead, our models project diverging responses, including downslope expansion and large areas projected to remain stable. Lastly, a significant part of the area expected to change is already affected by land use changes, which has important implications for management. This, and the inclusion of a comprehensive uncertainty analysis, will help to inform conservation strategies in the Tropical Andes, and to guide similar assessments for other tropical mountains. PMID:23667651

  11. Climate condition in the Central Europe during the Weichselian Ice Sheet according to the Educational Global Climate Modeling Project

    Microsoft Academic Search

    Izabela Szuman; Bartosz Czernecki

    2010-01-01

    The expansion and retreat of the ice sheet is controlled by climate changes, and from the other hand, a huge ice mass influences on the climate in the regional scale. This mechanism is commonly known as the fact but often without making reconstruction by using climatological modeling. The purpose of our study is to reconstruct the climate condition during the

  12. Statistical Modeling of Low Flow Conditions based on Climatic Indicators

    NASA Astrophysics Data System (ADS)

    Fangmann, Anne; Haberlandt, Uwe

    2015-04-01

    Regression-based approaches in climate change impact assessment may pose a practical alternative to the application of process-based hydrological models, especially with respect to low flow extremes. Extended durations and spatial dimensions allow for a quantitative assessment and exploitation of the interrelations between atmospheric driving forces and streamflow response during dry periods, and eventually for the prognosis of future low flow conditions based on climate model input. This study aims at using combinations of climatic indicators, quantifying a variety of meteorological drought characteristics, to model specific low flow indices, based solely on multiple linear regressions. The area under investigation is the federal state of Lower Saxony, Germany. Daily time series of climate and streamflow data pose the basis for calculation of a set of meteorological and hydrological indices, serving as regressors and regressands, respectively. Two approaches are being analyzed: a) a station-based approach, fitting a specific regression equation at each discharge gauge with sufficient record length, and b) a regional approach, enabling the estimation of low flow indices at ungauged sites and stations with minor record length. The station-based procedure is used for estimation of annual low flow index values from annual meteorological conditions. Subsequent fitting of distribution functions to the estimated values allows for the assessment of return periods of the low flow indices. The regionalization, on the other hand, is designed to directly estimate the shapes of the distribution functions by applying L-moment regressions, enabling a direct assessment of specific index values for the return periods in demand.

  13. Sensitivity of Climate to Diapycnal Diffusivity: Part I. Equilibrium State; Part II. Global Warming Scenario

    E-print Network

    Dalan, Fabio.

    Part I: The diapycnal diffusivity in the ocean is one of the least known parameters in current climate models. Measurements of this diffusivity are sparse and insufficient for compiling a global map. Inferences from inverse ...

  14. Asynchronous marine-terrestrial signals of the last deglacial warming in East Asia associated with low- and high-latitude climate changes.

    PubMed

    Xu, Deke; Lu, Houyuan; Wu, Naiqin; Liu, Zhenxia; Li, Tiegang; Shen, Caiming; Wang, Luo

    2013-06-11

    A high-resolution multiproxy record, including pollen, foraminifera, and alkenone paleothermometry, obtained from a single core (DG9603) from the Okinawa Trough, East China Sea (ECS), provided unambiguous evidence for asynchronous climate change between the land and ocean over the past 40 ka. On land, the deglacial stage was characterized by rapid warming, as reflected by paleovegetation, and it began ca. 15 kaBP, consistent with the timing of the last deglacial warming in Greenland. However, sea surface temperature estimates from foraminifera and alkenone paleothermometry increased around 20-19 kaBP, as in the Western Pacific Warm Pool (WPWP). Sea surface temperatures in the Okinawa Trough were influenced mainly by heat transport from the tropical western Pacific Ocean by the Kuroshio Current, but the epicontinental vegetation of the ECS was influenced by atmospheric circulation linked to the northern high-latitude climate. Asynchronous terrestrial and marine signals of the last deglacial warming in East Asia were thus clearly related to ocean currents and atmospheric circulation. We argue that (i) early warming seawater of the WPWP, driven by low-latitude insolation and trade winds, moved northward via the Kuroshio Current and triggered marine warming along the ECS around 20-19 kaBP similar to that in the WPWP, and (ii) an almost complete shutdown of the Atlantic Meridional Overturning Circulation ca. 18-15 kaBP was associated with cold Heinrich stadial-1 and delayed terrestrial warming during the last deglacial warming until ca. 15 kaBP at northern high latitudes, and hence in East Asia. Terrestrial deglacial warming therefore lagged behind marine changes by ca. 3-4 ka. PMID:23720306

  15. Climate-driven warming during spring destabilises a Daphnia population: a mechanistic food web approach.

    PubMed

    Wagner, Annekatrin; Benndorf, Jürgen

    2007-03-01

    Temperature-driven changes in interactions between populations are crucial to the estimation of the impact of global warming on aquatic food webs. We analysed inter-annual variability in two data sets from Bautzen reservoir, Germany. In a long-term data set (1981-1999) we examined the pelagic phenology of Daphnia galeata, a keystone species, the invertebrate predator Leptodora kindtii, phytoplankton and Secchi depth in relation to water temperature and the North Atlantic Oscillation index. In a short-term data set (1995-1998) we examined food web relations, particularly the consumption of D. galeata by young-of-the-year (YOY) percids and L. kindtii and rates of population change of D. galeata (abundance, recruitment pattern and non-consumptive mortality). The start of the clear-water stage (CWS) was correlated with winter temperatures. It started 5.8 days earlier per degree warming after warm winters (mean January-March temperature>or=2.5 degrees C) compared to cold winters (mean temperature<2.5 degrees C). However, the end of the CWS remained relatively constant. Predation by L. kindtii and YOY percids on D. galeata started distinctly earlier, i.e. by 13.0 and 6.5 days per degree warming, respectively, in years when the average May temperature was high (>or=14 degrees C) compared to years when it was low (<14 degrees C). Significant reductions of Daphnia abundance in midsummer occurred only in years in which the mean May temperature exceeded 14 degrees C. This temperature regime resulted in a match of over-exploitation of food resources by Daphnia during the CWS and strong predation by YOY percids and L. kindtii. Consumptive mortality increased at higher rates with a rise in temperature than net recruitment, resulting in lower Daphnia densities at the end of the CWS. Our data suggest that even low warming by 1.7 degrees C during a short, but critical seasonal period, resulting in the coincidence of two or more factors adversely affecting a keystone species, such as Daphnia, may induce changes in whole lake food webs and thus alter entire ecosystems. PMID:17120058

  16. Global warming elucidated

    Microsoft Academic Search

    Shen

    1995-01-01

    The meaning of global warming and its relevance to everyday life is explained. Simple thermodynamics is used to predict an oscillatory nature of the change in climate due to global warming. Global warming causes extreme events and bad weather in the near term. In the long term it may cause the earth to transition to another equilibrium state through many

  17. QUESTIONS ABOUT GLOBAL WARMING

    E-print Network

    QUESTIONS ABOUT GLOBAL WARMING ¥IS IT REAL? ¥IS IT IMPORTANT? ¥WHAT IS IT DUE TO? ¥HOW MUCH MORE in the atmosphere, giving Earth its temperate climate. Global Atmosphere, Global Warming GLOBAL TEMPERATURE TRENDÕt a cure for global warming! Aerosols only last a short while in the atmosphere, they would have

  18. Projection of climatic suitability for Aedes albopictus Skuse (Culicidae) in Europe under climate change conditions

    NASA Astrophysics Data System (ADS)

    Fischer, Dominik; Thomas, Stephanie Margarete; Niemitz, Franziska; Reineking, Björn; Beierkuhnlein, Carl

    2011-07-01

    During the last decades the disease vector Aedes albopictus ( Ae. albopictus) has rapidly spread around the globe. The spread of this species raises serious public health concerns. Here, we model the present distribution and the future climatic suitability of Europe for this vector in the face of climate change. In order to achieve the most realistic current prediction and future projection, we compare the performance of four different modelling approaches, differentiated by the selection of climate variables (based on expert knowledge vs. statistical criteria) and by the geographical range of presence records (native range vs. global range). First, models of the native and global range were built with MaxEnt and were either based on (1) statistically selected climatic input variables or (2) input variables selected with expert knowledge from the literature. Native models show high model performance (AUC: 0.91-0.94) for the native range, but do not predict the European distribution well (AUC: 0.70-0.72). Models based on the global distribution of the species, however, were able to identify all regions where Ae. albopictus is currently established, including Europe (AUC: 0.89-0.91). In a second step, the modelled bioclimatic envelope of the global range was projected to future climatic conditions in Europe using two emission scenarios implemented in the regional climate model COSMO-CLM for three time periods 2011-2040, 2041-2070, and 2071-2100. For both global-driven models, the results indicate that climatically suitable areas for the establishment of Ae. albopictus will increase in western and central Europe already in 2011-2040 and with a temporal delay in eastern Europe. On the other hand, a decline in climatically suitable areas in southern Europe is pronounced in the Expert knowledge based model. Our projections appear unaffected by non-analogue climate, as this is not detected by Multivariate Environmental Similarity Surface analysis. The generated risk maps can aid in identifying suitable habitats for Ae. albopictus and hence support monitoring and control activities to avoid disease vector establishment.

  19. Contrasting Historical and Recent Breakup Styles on the Meade River of Arctic Alaska in the Context of a Warming Climate

    NASA Astrophysics Data System (ADS)

    Beck, R. A.; Hinkel, K. M.; Eisner, W. R.; Whiteman, D.; Arp, C. D.; Machida, R.; Cuomo, C.; Su, H.; Liu, H.; Kim, C.; Rettig, A.; Ivenso, C.; Yang, B.; Wu, Q.; Wang, S.; Frey, K. E.; Lenters, J. D.; Potter, B. L.

    2013-12-01

    Although data for temporal spring river ice breakup are available for a number of Arctic rivers, there is a paucity of information related to the type of breakup. The Arctic Climate Impact Assessment (ACIA) of 2005 predicted a transition from mechanical to thermal spring breakup of ice cover on arctic rivers, with this shift being greatest in exclusively Arctic watersheds where observed warming is most pronounced. We describe a rare instance of an entirely Arctic river with limited but well documented historical and recent data regarding the type of breakup. Time-series ground imagery of spring breakup from 1966, 1975, 1978, 2009, 2010 and 2012, in combination with interviews of local inhabitants, documents a shift from predominantly mechanical to predominantly thermal breakup after spring 1978 and by spring 2009 within the context of a locally and regionally warming Arctic. Recent (post-2010) and rare cloud-free visible satellite imagery shows an irregular pattern of breakup along the southern two thirds of the river. The resultant shift from predominantly mechanical to predominantly thermal breakup is predicted to result in significant changes to water, sediment, nutrient and organic carbon fluxes, as well as riparian ecology and human activities. Meade River Breakup - Spring 1966 Meade River Breakup - Spring 2010

  20. Variability in projected elevation dependent warming in boreal midlatitude winter in CMIP5 climate models and its potential drivers

    NASA Astrophysics Data System (ADS)

    Rangwala, Imtiaz; Sinsky, Eric; Miller, James R.

    2015-06-01

    The future rate of climate change in mountains has many potential human impacts, including those related to water resources, ecosystem services, and recreation. Analysis of the ensemble mean response of CMIP5 global climate models (GCMs) shows amplified warming in high elevation regions during the cold season in boreal midlatitudes. We examine how the twenty-first century elevation-dependent response in the daily minimum surface air temperature [d(?Tmin)/dz] varies among 27 different GCMs during winter for the RCP 8.5 emissions scenario. The focus is on regions within the northern hemisphere mid-latitude band between 27.5°N and 40°N, which includes both the Rocky Mountains and the Tibetan Plateau/Himalayas. We find significant variability in d(?Tmin)/dz among the individual models ranging from 0.16 °C/km (10th percentile) to 0.97 °C/km (90th percentile), although nearly all of the GCMs (24 out of 27) show a significant positive value for d(?Tmin)/dz. To identify some of the important drivers associated with the variability in d(?Tmin)/dz during winter, we evaluate the co-variance between d(?Tmin)/dz and the differential response of elevation-based anomalies in different climate variables as well as the GCMs' spatial resolution, their global climate sensitivity, and their elevation-dependent free air temperature response. We find that d(?Tmin)/dz has the strongest correlation with elevation-dependent increases in surface water vapor, followed by elevation-dependent decreases in surface albedo, and a weak positive correlation with the GCMs' free air temperature response.

  1. The thermocline feedback in the western-central equatorial Pacific: A key player for ENSO in a warming climate?

    NASA Astrophysics Data System (ADS)

    Dewitte, Boris; Yeh, Sang-Wook; Thual, Sulian

    2013-04-01

    Vertical stratification changes at low frequency over the last decades are the largest in western-central Pacific and have the potential to modify the balance between ENSO feedback processes. Using Reanalysis products, we show evidence of an increase in thermocline feedback in the western-central equatorial Pacific over the last 50 years, and in particular after the climate shift of 1976. The thermocline feedback becomes more effective due to the increased stratification in the vicinity of the mean thermocline, which is shown to be concomitent with long-term change of the recharge-discharge process. The increased stratification leads to an increase of vertical advection variability twice as large as its increase resulting from the increased in ENSO amplitude (positive asymmetry) in the eastern Pacific that connects to the thermocline in the western-central Pacific through the basin-scale 'tilt' mode. Although the zonal advective feedback is dominant over the western-central equatorial Pacific, the more effective thermocline feedback allows for counteracting its warming (cooling) effect during warm (cold) event, leading to the reduced covariability between SST and thermocline depth anomalies in the NINO4 (160°E-150°W; 5°S-5°N) region after the 1976 climate shift. This counter-intuitive relationship between thermocline feedback strength as derived from the linear relationship between SST and thermocline fluctuations and stratification changes is also investigated in a long-term coupled general circulation model (CGCM) simulation. A recharge-discharge conceptual coupled model is used to show that the change in thermocline feedback associated to increased vertical stratification in the central-western Pacific as simulated by the CGCMs in which the green-house gazes concentration is increased (CMIP5) can lead to an ENSO regime accounting for Central Pacific El Niño events.

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

    PubMed Central

    Harrison, Susan; Damschen, Ellen I.; Grace, James B.

    2010-01-01

    Downscaling from the predictions of general climate models is critical to current strategies for mitigating species loss caused by climate change. A key impediment to this downscaling is that we lack a fully developed understanding of how variation in physical, biological, or land-use characteristics mediates the effects of climate change on ecological communities within regions. We analyzed change in understory herb communities over a 60-y period (1949/1951–2007/2009) in a complex montane landscape (the Siskiyou Mountains, Oregon) where mean temperatures have increased 2 °C since 1948, similar to projections for other terrestrial communities. Our 185 sites included primary and secondary-growth lower montane forests (500–1.200 m above sea level) and primary upper montane to subalpine forests (1,500–2,100 m above sea level). In lower montane forests, regardless of land-use history, we found multiple herb-community changes consistent with an effectively drier climate, including lower mean specific leaf area, lower relative cover by species of northern biogeographic affinity, and greater compositional resemblance to communities in southerly topographic positions. At higher elevations we found qualitatively different and more modest changes, including increases in herbs of northern biogeographic affinity and in forest canopy cover. Our results provide community-level validation of predicted nonlinearities in climate change effects. PMID:20974978

  3. USDA Forest Service Proceedings RMRS-P-18. 2001. 325 Modeling Aspen Responses to Climatic Warming and Insect Defoliation in Western Canada Hogg

    E-print Network

    important deciduous tree species in the North American boreal forest. It is especially abundant as pureUSDA Forest Service Proceedings RMRS-P-18. 2001. 325 Modeling Aspen Responses to Climatic Warming and Insect Defoliation in Western Canada Hogg 1Canadian Forest Service, Edmonton, Alberta, Canada. Modeling

  4. The paradox of cooling streams in a warming world: regional climate trends do not parallel variable local trends in stream temperature in the Pacific continental United States

    USGS Publications Warehouse

    Arismendi, Ivan; Johnson, Sherri; Dunham, Jason B.; Haggerty, Roy; Hockman-Wert, David

    2012-01-01

    Temperature is a fundamentally important driver of ecosystem processes in streams. Recent warming of terrestrial climates around the globe has motivated concern about consequent increases in stream temperature. More specifically, observed trends of increasing air temperature and declining stream flow are widely believed to result in corresponding increases in stream temperature. Here, we examined the evidence for this using long-term stream temperature data from minimally and highly human-impacted sites located across the Pacific continental United States. Based on hypothesized climate impacts, we predicted that we should find warming trends in the maximum, mean and minimum temperatures, as well as increasing variability over time. These predictions were not fully realized. Warming trends were most prevalent in a small subset of locations with longer time series beginning in the 1950s. More recent series of observations (1987-2009) exhibited fewer warming trends and more cooling trends in both minimally and highly human-influenced systems. Trends in variability were much less evident, regardless of the length of time series. Based on these findings, we conclude that our perspective of climate impacts on stream temperatures is clouded considerably by a lack of long-termdata on minimally impacted streams, and biased spatio-temporal representation of existing time series. Overall our results highlight the need to develop more mechanistic, process-based understanding of linkages between climate change, other human impacts and stream temperature, and to deploy sensor networks that will provide better information on trends in stream temperatures in the future.

  5. Global warming

    SciTech Connect

    Not Available

    1990-02-01

    The earth seems to be getting warmer, but scientists are unsure about the rate and extent of this trend. GAO found that the administration has not established a national policy, defined agency role and interagency relationships, or provided adequate guidance to agencies on how to address the global warming issue. This report states that U.S. administration policy so far has concentrated on doing the scientific research needed to reduce any uncertainty about the timing and threat of global warming. The United States has also focused on assuming a leading international role in formulating policy responses aimed at limiting or adapting to world climate change.

  6. Global warming and neurodegenerative disorders: speculations on their linkage

    PubMed Central

    Habibi, Laleh; Perry, George; Mahmoudi, Morteza

    2014-01-01

    Climate change is having considerable impact on biological systems. Eras of ice ages and warming shaped the contemporary earth and origin of creatures including humans. Warming forces stress conditions on cells. Therefore, cells evolved elaborate defense mechanisms, such as creation of heat shock proteins, to combat heat stress. Global warming is becoming a crisis and this process would yield an undefined increasing rate of neurodegenerative disorders in future decades. Since heat stress is known to have a degenerative effects on neurons and, conversely, cold conditions have protective effect on these cells, we hypothesize that persistent heat stress forced by global warming might play a crucial role in increasing neurodegenerative disorders. PMID:25671171

  7. Weather conditions and visits to the medical wing of emergency rooms in a metropolitan area during the warm season in Israel: a predictive model

    NASA Astrophysics Data System (ADS)

    Novikov, Ilya; Kalter-Leibovici, Ofra; Chetrit, Angela; Stav, Nir; Epstein, Yoram

    2012-01-01

    Global climate changes affect health and present new challenges to healthcare systems. The aim of the present study was to analyze the pattern of visits to the medical wing of emergency rooms (ERs) in public hospitals during warm seasons, and to develop a predictive model that will forecast the number of visits to ERs 2 days ahead. Data on daily visits to the ERs of the four largest medical centers in the Tel-Aviv metropolitan area during the warm months of the year (April-October, 2001-2004), the corresponding daily meteorological data, daily electrical power consumption (a surrogate marker for air-conditioning), air-pollution parameters, and calendar information were obtained and used in the analyses. The predictive model employed a time series analysis with transitional Poisson regression. The concise multivariable model was highly accurate ( r 2 = 0.819). The contribution of mean daily temperature was small but significant: an increase of 1°C in ambient temperature was associated with a 1.47% increase in the number of ER visits ( P < 0.001). An increase in electrical power consumption significantly attenuated the effect of weather conditions on ER visits by 4% per 1,000 MWh ( P < 0.001). Higher daily mean SO2 concentrations were associated with a greater number of ER visits (1% per 1 ppb increment; P = 0.017). Calendar data were the main predictors of ER visits ( r 2 = 0.794). The predictive model was highly accurate in forecasting the number of visits to ERs 2 days ahead. The marginal effect of temperature on the number of ER visits can be attributed to behavioral adaptations, including the use of air-conditioning.

  8. A theoretical study of the performance of wind-driven pumps under Jordanian climatic conditions

    Microsoft Academic Search

    Khaled S. AlQdah; Omar Badran; Ahmed Al-Salaymeh

    2011-01-01

    The utilization of renewable energy resources such as wind energy has increased recently due to the rising concern regarding global warming and the associated impact upon climate change, the increasingly rapid depletion of fossil fuel resources and the desire to maximize security of fuel supply. This study deals with autonomous wind pump applications for remote areas in Jordan. The performance

  9. Intensification of the Southern Hemisphere summertime subtropical anticyclones in a warming climate

    E-print Network

    Wenhong Li,1 Laifang Li,1 Mingfang Ting,2 Yi Deng,3 Yochanan Kushnir,2 Yimin Liu,4 Yi Lu,3 Chunzai Wang,5 as suggested by Li et al. (2012) indicates increasingly important roles played by SAs in modulating weather and climate on regional and global scales. Citation: Li, W., L. Li, M. Ting, Y. Deng, Y. Kushnir, Y. Liu, Y

  10. Going against the flow: potential mechanisms for unexpected downslope range shifts in a warming climate

    E-print Network

    Zimmermann, Niklaus E.

    climate Jonathan Lenoir, Jean-Claude Ge´gout, Antoine Guisan, Pascal Vittoz, Thomas Wohlgemuth, Niklaus E^t-Bois (LERFoB), 14 rue Girardet, FR-54000 Nancy, France. Á J.-C. Ge´gout, AgroParisTech, UMR1092 Agro

  11. Juniperus communis : victim of the combined action of climate warming and nitrogen deposition?

    Microsoft Academic Search

    K. Verheyen; S. Adriaenssens; R. Gruwez; I. M. Michalczyk; L. K. Ward; Y. Rosseel; A. Van den Broeck; D. García

    2009-01-01

    Research on the combined effects of climate change and nitrogen deposition on reproductive traits, and especially on the production of viable seeds, is still scarce despite their importance for population persistence and expansion. Hence, in this study we set out to investigate the direct and indirect effects of the above-mentioned global change drivers on seed viability in the coniferous shrub

  12. Potential Climate Change Effects on Warm-Season Livestock Production in the Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climate changes suggested by some global circulation models (GCM) will impact livestock production systems in the Great Plains region of the United States. Production/response models for growing swine and beef cattle, and milk-producing dairy cattle, were developed based on summary information conta...

  13. Energy and global warming impacts of next generation refrigeration and air conditioning technologies

    Microsoft Academic Search

    J. R. Sand; S. K. Fischer; V. D. Baxter

    1996-01-01

    Significant developments have occurred in hydrofluorocarbon (HFC) and the application of ammonia and hydrocarbons as refrigerant working fluids since the original TEWI (Total Equivalent Warming Impact) report in 1991. System operating and performance data on alternative refrigerants and refrigeration technologies justify and updated evaluation of these new alternative refrigerants and competing technologies in well-characterized applications. Analytical and experimental results are

  14. Changes in sub-daily precipitation extremes in a global climate model with super-parameterization under CO2 warming

    NASA Astrophysics Data System (ADS)

    Khairoutdinov, Marat; Zhou, Xin

    2015-04-01

    Virtually all of the projections for future change of extreme precipitation statistics under CO2 warming have been made using global climate models (GCMs) in which clouds and, in particular, convective cloud systems are not explicitly resolved, but rather parameterized. In our study, a different kind of a GCM, a super-parameterized Community Atmosphere Model (SP-CAM), is employed. In SP-CAM, all the conventional cloud parameterizations are replaced with a small-domain cloud resolving model (CRM), called super-parameterization (SP). The SP is embedded in each grid column of the host GCM. The resolution of each embedded CRM is 4 km, which is generally sufficient to explicitly represent deep convection, which is mostly responsible for extreme precipitation events. In this study, we use the SP-CAM to contrast to the present and to conventional climate model, CAM, the sub-daily extreme precipitation statistics in response to the sea-surface temperatures (SSTs) and CO2 levels as projected for the end of 21st century in response to the IPCC AR5 RCP8.5 emission scenario. Different mechanisms for extreme precipitation changes are discussed.

  15. Net exchanges of CO2, CH4, and N2O between China's terrestrial ecosystems and the atmosphere and their contributions to global climate warming

    NASA Astrophysics Data System (ADS)

    Tian, Hanqin; Xu, Xiaofeng; Lu, Chaoqun; Liu, Mingliang; Ren, Wei; Chen, Guangsheng; Melillo, Jerry; Liu, Jiyuan

    2011-06-01

    China's terrestrial ecosystems have been recognized as an atmospheric CO2 sink; however, it is uncertain whether this sink can alleviate global warming given the fluxes of CH4 and N2O. In this study, we used a process-based ecosystem model driven by multiple environmental factors to examine the net warming potential resulting from net exchanges of CO2, CH4, and N2O between China's terrestrial ecosystems and the atmosphere during 1961-2005. In the past 45 years, China's terrestrial ecosystems were found to sequestrate CO2 at a rate of 179.3 Tg C yr-1 with a 95% confidence range of (62.0 Tg C yr-1, 264.9 Tg C yr-1) while emitting CH4 and N2O at rates of 8.3 Tg C yr-1 with a 95% confidence range of (3.3 Tg C yr-1, 12.4 Tg C yr-1) and 0.6 Tg N yr-1 with a 95% confidence range of (0.2 Tg N yr-1, 1.1 Tg N yr-1), respectively. When translated into global warming potential, it is highly possible that China's terrestrial ecosystems mitigated global climate warming at a rate of 96.9 Tg CO2eq yr-1 (1 Tg = 1012 g), substantially varying from a source of 766.8 Tg CO2eq yr-1 in 1997 to a sink of 705.2 Tg CO2eq yr-1 in 2002. The southeast and northeast of China slightly contributed to global climate warming; while the northwest, north, and southwest of China imposed cooling effects on the climate system. Paddy land, followed by natural wetland and dry cropland, was the largest contributor to national warming potential; forest, followed by woodland and grassland, played the most significant role in alleviating climate warming. Our simulated results indicate that CH4 and N2O emissions offset approximately 84.8% of terrestrial CO2 sink in China during 1961-2005. This study suggests that the relieving effects of China's terrestrial ecosystems on climate warming through sequestering CO2 might be gradually offset by increasing N2O emission, in combination with CH4 emission.

  16. Insensitivity of global warming potentials to carbon dioxide emission scenarios

    Microsoft Academic Search

    Ken Caldeira; James F. Kasting

    1993-01-01

    GLOBAL warming potentials for radiatively active trace gases (such as methane and chlorofluorocarbons) have generally been expressed1-2 relative to the time-integrated climate forcing per unit emission of carbon dioxide. Previous attempts to estimate the integrated climate forcing per unit CO2 emitted have focused on perturbations to steady-state conditions in carbon-cycle models. But for non-steady-state conditions, the integrated climate forcing from

  17. Energy fluxes in a high Arctic tundra heath subjected to strong climate warming

    NASA Astrophysics Data System (ADS)

    Lund, M.; Hansen, B. U.; Pedersen, S. H.; Stiegler, C.; Tamstorf, M. P.

    2012-12-01

    During recent decades the observed warming in the Arctic has been almost twice as large as the global average. The implications of such strong warming on surface energy balance, regulating permafrost thaw, hydrology, soil stability and carbon mineralization, need to be assessed. In Zackenberg, northeast Greenland, measurements of energy balance components in various environments have been performed since late 90's, coordinated by Zackenberg Ecological Research Operations. During 1996-2009, mean annual temperature in the area has increased by ca. 0.15 °C yr-1; while maximum thaw depth has increased by 1.4-1.8 cm yr-1. Eddy covariance measurements of energy fluxes have been performed in a Cassiope heath plant community, a commonly occurring tundra ecosystem type in circumpolar middle and high Arctic areas, in Zackenberg allowing for detailed investigations of relationships between energy fluxes and meteorological and soil physical characteristics. As the available data set spans more than a decade, possible trends in energy flux components resulting from warming related changes such as earlier snow melt, increased active layer depth and higher temperatures can be investigated. This presentation will focus on the mid-summer period from which eddy covariance measurements are available. The summer-time energy partitioning at the Zackenberg tundra heath site will be characterized using ratios of sensible, latent and ground heat flux to net radiation and Bowen ratio, whereas the surface characteristics will be described using surface resistance, McNaughton and Jarvis ? value and Priestley-Taylor ? coefficient. Furthermore, we aim to estimate the full year, all energy balance components for the tundra heath site using Snow Model (Liston and Elder 2006) for the dark winter period during which no eddy covariance measurements are available. The snow cover duration in the area is a major regulator of the energy partitioning. Early results point towards high summer-time surface resistance with low evapotranspiration rates, likely due to low atmospheric demand regulated by the dominating onshore summer winds carrying cold and moist air. As a result, Bowen ratios are high and a large portion of the available energy is transformed into sensible heat and ground heat fluxes. Further results will be presented and discussed at the conference.

  18. Sensitivity of subalpine tree seedlings and alpine plants to natural and manipulated climate variation: Initial results from an Alpine Treeline Warming Experiment (Invited)

    NASA Astrophysics Data System (ADS)

    Kueppers, L. M.

    2010-12-01

    Niche models and paleoecological studies indicate that future climate change will alter the geographic distributions of plant species. Changes in temperature, snowmelt timing, or moisture conditions at one edge of a species’ range may have different consequences for recruitment, carbon exchange, phenology, and survival than changes at another edge. Similarly, local genetic adaptation may constrain species and community responses to climate change. We have established a new experiment to investigate potential shifts in the distribution of subalpine tree species, and the alpine species they might replace. We are asking how tree species recruitment and alpine species growth and reproduction vary within their current ranges, and in response to temperature and soil moisture manipulations. We are also examining whether genetic provenance and ecosystem processes constrain tree seedling and alpine herb responses. Our Alpine Treeline Warming Experiment is located across three sites at Niwot Ridge, CO, ranging from near the lower limit of subalpine forest to alpine tundra. We use infrared heaters to raise growing season surface soil temperatures by 4-5°C, and to lengthen the growing season. The warming treatment is crossed with a soil moisture manipulation to distinguish effects due to higher temperatures from those due to drier soil. Each plot is a common garden sown with high and low elevation provenances of limber pine (Pinus flexilis) and Engelmann spruce (Picea engelmannii). We established an additional set of experimental plots to examine treatment effects on alpine species phenology, growth and reproduction. Under ambient conditions in 2009, tree seedling germination rate, lifespan, and first season survival was higher within the species’ current range than in the alpine, and for Engelmann spruce, was higher at the low elevation limit than the high elevation limit. Source population (low vs. high elevation) was a significant factor explaining natural variation in germination rates and timing, seedling physiology, and seedling survival. In 2010, the first season with experimental effects data, the timing of germination was substantially advanced with warming for both species, and warming appeared to increase germination rates for limber pine, but to depress rates for Engelmann spruce at treeline. Seedling carbon balance was negative at the warmest leaf temperatures and there is some indication that the low elevation provenance has a higher total assimilation rate and net carbon gain than the high elevation provenance. Water availability was an important driver of variation in carbon assimilation through the growing season. Our early results suggest that with higher germination rates and lower mortality rates, limber pine is better able to recruit into the alpine than Engelmann spruce, and that lower elevation provenances of limber pine are better at assimilating carbon for growth regardless of site. Ultimate success in seedling establishment may be more contingent on water availability than temperature, even at these high elevations.

  19. Comparison of Shoulder Range of Motion, Strength, and Playing Time in Uninjured High School Baseball Pitchers Who Reside in Warm- and Cold-Weather Climates

    PubMed Central

    Kaplan, Kevin M.; ElAttrache, Neal S.; Jobe, Frank W.; Morrey, Bernard F.; Kaufman, Kenton R.; Hurd, Wendy J.

    2014-01-01

    Background There is an assumption that baseball athletes who reside in warm-weather climates experience larger magnitude adaptations in throwing shoulder motion and strength compared with their peers who reside in cold-weather climates. Hypotheses (1) The warm-weather climate (WWC) group would exhibit more pronounced shoulder motion and strength adaptations than the cold-weather climate (CWC) group, and (2) the WWC group would participate in pitching activities for a greater proportion of the year than the CWC group, with the time spent pitching predicting throwing shoulder motion and strength in both groups. Study Design Cross-sectional study; Level of evidence, 3. Methods One hundred uninjured high school pitchers (50 each WWC, CWC) were recruited. Rotational shoulder motion and isometric strength were measured and participants reported the number of months per year they pitched. To identify differences between groups, t tests were performed; linear regression was used to determine the influence of pitching volume on shoulder motion and strength. Results The WWC group pitched more months per year than athletes from the CWC group, with the number of months spent pitching negatively related to internal rotation motion and external rotation strength. The WWC group exhibited greater shoulder range of motion in all planes compared with the CWC group, as well as significantly lower external rotation strength and external/internal rotation strength ratios. There was no difference in internal rotation strength between groups, nor a difference in the magnitude of side-to-side differences for strength or motion measures. Conclusion Athletes who reside in cold- and warm-weather climates exhibit differences in throwing shoulder motion and strength, related in part to the number of months spent participating in pitching activities. The amount of time spent participating in pitching activities and the magnitude of range of motion and strength adaptations in athletes who reside in warm-weather climates may make these athletes more susceptible to throwing-related injuries. PMID:21051421

  20. Impact of warming climate on the monsoon and water resources of a western Himalayan watershed in the Upper Indus Basin

    NASA Astrophysics Data System (ADS)

    Khan, Asif; Richards, Keith S.; Parker, Geoffrey T.; McRobie, Allan; Booij, Martijn J.

    2015-04-01

    This study discusses the impact of a warming climate on the monsoon and on water resources in the Astore watershed, a major tributary of the Upper Indus Basin (UIB). It uses precipitation and temperature time series data from climatic stations, European Reanalysis (ERA) interim precipitation data, and monthly river flow data, all for the 1984-2009 period. Monthly average temperature data show statistically significant increasing trends for November-June through this period, while June and July, which experience episodic and intense precipitation, show statistically significant but opposing trends between the first and second halves of the period. To examine precipitation and flow data in more detail, two equal sub-periods were defined; 1984-1996 (T1) and 1997-2009 (T2). Basin-wide average annual precipitation (based on ERA data) declined by ~29% from 1481 mm/yr in T1 to 1148 inT2, whereas during the same periods flows declined by only ~17% (1245 to 1061 mm/yr), suggesting an increase in glacier melt in the T2 period. Spring to early summer flows increased during the T2 period concomitant with shift in the streamflow peak from July to June. Increasing spring discharge, the shift in timing of annual peak discharge, and an increase in the glacial melt component in river flows have been accompanied by a depletion of glacial storage within the Astore watershed, especially in the T2 period. If recent trends in climate and river flow continue in the future, then river flows will eventually decrease more sharply once the glacial reserves can no longer provide sustained nourishment to the river waters. Thus, there is a vital need to prepare and adopt policies for water resource management and reservoir operation that support sustainable development, agricultural expansion, and increased hydro-power generation.

  1. Current analogues of future climate indicate the likely response of a sensitive montane tropical avifauna to a warming world.

    PubMed

    Anderson, Alexander S; Storlie, Collin J; Shoo, Luke P; Pearson, Richard G; Williams, Stephen E

    2013-01-01

    Among birds, tropical montane species are likely to be among the most vulnerable to climate change, yet little is known about how climate drives their distributions, nor how to predict their likely responses to temperature increases. Correlative models of species' environmental niches have been widely used to predict changes in distribution, but direct tests of the relationship between key variables, such as temperature, and species' actual distributions are few. In the absence of historical data with which to compare observations and detect shifts, space-for-time substitutions, where warmer locations are used as analogues of future conditions, offer an opportunity to test for species' responses to climate. We collected density data for rainforest birds across elevational gradients in northern and southern subregions within the Australian Wet Tropics (AWT). Using environmental optima calculated from elevational density profiles, we detected a significant elevational difference between the two regions in ten of 26 species. More species showed a positive (19 spp.) than negative (7 spp.) displacement, with a median difference of ?80.6 m across the species analysed that is concordant with that expected due to latitudinal temperature differences (?75.5 m). Models of temperature gradients derived from broad-scale climate surfaces showed comparable performance to those based on in-situ measurements, suggesting the former is sufficient for modeling impacts. These findings not only confirm temperature as an important factor driving elevational distributions of these species, but also suggest species will shift upslope to track their preferred environmental conditions. Our approach uses optima calculated from elevational density profiles, offering a data-efficient alternative to distribution limits for gauging climate constraints, and is sensitive enough to detect distribution shifts in this avifauna in response to temperature changes of as little as 0.4 degrees. We foresee important applications in the urgent task of detecting and monitoring impacts of climate change on montane tropical biodiversity. PMID:23936005

  2. Adult activity and temperature preference drives region-wide damselfly (Zygoptera) distributions under a warming climate.

    PubMed

    Corser, Jeffrey D; White, Erin L; Schlesinger, Matthew D

    2015-04-01

    We analysed a recently completed statewide odonate Atlas using multivariate linear models. Within a phylogenetically explicit framework, we developed a suite of data-derived traits to assess the mechanistic distributional drivers of 59 species of damselflies in New York State (NYS). We found that length of the flight season (adult breeding activity period) mediated by thermal preference drives regional distributions at broad (10(5) km(2)) scales. Species that had longer adult flight periods, in conjunction with longer growing seasons, had significantly wider distributions. These intrinsic traits shape species' responses to changing climates and the mechanisms behind such range shifts are fitness-based metapopulation processes that adjust phenology to the prevailing habitat and climate regime through a photoperiod filter. PMID:25878048

  3. Global Climate Change — the Latest Assessment: Does Global Warming Warrant a Health Warning?

    Microsoft Academic Search

    RT Watson; AJ McMichael

    2001-01-01

    Global climate change is a qualitatively distinct, and very significant, addition to the spectrum of environmental health\\u000a hazards encountered by humankind. Historically, environmental health concerns have focused on toxicological or microbiological\\u000a risks to health from local exposures. However, the scale of environmental health hazards is today increasing; indeed, the\\u000a burgeoning human impact on the environment has begun to alter global

  4. The role of climate variability and global warming in the dieback of Northern Hardwoods

    Microsoft Academic Search

    Allan N. D. Auclair; John T. Lill; Carmen Revenga

    1996-01-01

    The severity of dieback in Northern Hardwood Forests of Canada and the United States this century (1910–1990) was reconstructed from pathology records and compared to indices of extreme weather stresses in the region, and to changes in global temperatures and climatic variability over the same period. Thaw-freeze and root-freeze events in winter and early spring were key factors intriggering (and

  5. Understanding land surface response to changing South Asian monsoon in a warming climate

    NASA Astrophysics Data System (ADS)

    Ramarao, M. V. S.; Krishnan, R.; Sanjay, J.; Sabin, T. P.

    2015-05-01

    Recent studies have drawn attention to a significant weakening trend of the South Asian monsoon circulation and an associated decrease in regional rainfall during the last few decades. While surface temperatures over the region have steadily risen during this period, most of the CMIP (Coupled Model Intercomparison Project) global climate models have difficulties in capturing the observed decrease of monsoon precipitation, thus limiting our understanding of the regional land surface response to monsoonal changes. This problem is investigated by performing two long-term simulation experiments, with and without anthropogenic forcing, using a variable resolution global climate model having high-resolution zooming over the South Asian region. The present results indicate that anthropogenic effects have considerably influenced the recent weakening of the monsoon circulation and decline of precipitation. It is seen that the simulated increase of surface temperature over the Indian region during the post-1950s is accompanied by a significant decrease of monsoon precipitation and soil moisture. Our analysis further reveals that the land surface response to decrease of soil moisture is associated with significant reduction in evapotranspiration over the Indian land region. A future projection, based on the representative concentration pathway 4.5 (RCP4.5) scenario of the Intergovernmental panel on Climate Change (IPCC), using the same high-resolution model indicates the possibility for detecting the summer-time soil drying signal over the Indian region during the 21st century, in response to climate change. While these monsoon hydrological changes have profound socioeconomic implications, the robustness of the high-resolution simulations provides deeper insights and enhances our understanding of the regional land surface response to the changing South Asian monsoon.

  6. Climatic controls of aboveground net primary production in semi-arid grasslands along a latitudinal gradient portend low sensitivity to warming

    USGS Publications Warehouse

    Mowll, Whitney; Blumenthal, Dana M.; Cherwin, Karie; Smith, Anine; Symstad, Amy; Vermeire, Lance; Collins, Scott L.; Smith, Melinda D.; Knapp, Alan K.

    2015-01-01

    Although climate models forecast warmer temperatures with a high degree of certainty, precipitation is the primary driver of aboveground net primary production (ANPP) in most grasslands. Conversely, variations in temperature seldom are related to patterns of ANPP. Thus forecasting responses to warming is a challenge, and raises the question: how sensitive will grassland ANPP be to warming? We evaluated climate and multi-year ANPP data (67 years) from eight western US grasslands arrayed along mean annual temperature (MAT; ~7-14 °C) and mean annual precipitation (MAP; ~250-500 mm) gradients. Weused regression and analysis of covariance to assess relationships between ANPP and temperature, as well as precipitation (annual and growing season) to evaluate temperature sensitivity of ANPP. We also related ANPP to the standardized precipitation evaporation index (SPEI), which combines precipitation and evapotranspiration to better represent moisture available for plant growth. Regression models indicated that variation in growing season temperature was negatively related to total and graminoid ANPP, but precipitation was a stronger predictor than temperature. Growing season temperature was also a significant parameter in more complex models, but again precipitation was consistently a stronger predictor of ANPP. Surprisingly, neither annual nor growing season SPEI were as strongly related to ANPP as precipitation. We conclude that forecasted warming likely will affect ANPP in these grasslands, but that predicting temperature effects from natural climatic gradients is difficult. This is because, unlike precipitation, warming effects can be positive or negative and moderated by shifts in the C3/C4 ratios of plant communities.

  7. Mechanism of Springback-Free Bending of High-Strength Steel Sheets under Warm Forming Conditions

    Microsoft Academic Search

    J. Yanagimoto; K. Oyamada

    2007-01-01

    Tensile loading-unloading tests of high-strength steel sheets in an elevated temperature range are conducted using a 100kN servo-controlled hydraulic dynamic fatigue testing machine, aiming at clarifying the mechanism of the springback-free phenomenon occurring in warm sheet forming. From stress-strain curves obtained by the tests, it is found that the abrupt decrease in the springback of formed steel sheets at approximately

  8. Numerical investigations on springback characteristics of aluminum sheet metal alloys in warm forming conditions

    Microsoft Academic Search

    Hong Seok Kim; Muammer Koç

    2008-01-01

    In this study, we investigated the effect of temperature gradients on the final part quality (i.e., springback) in warm forming of lightweight materials. Thermo-mechanically coupled finite element analysis (FEA) models encompassing the heating of the sheet blank and tooling, forming, part ejection, and cooling were developed for simple channel drawing process. A comparison was made between the 2D rigid and

  9. Effect of Pre-Cooling on Repeat-Sprint Performance in Seasonally Acclimatised Males During an Outdoor Simulated Team-Sport Protocol in Warm Conditions

    PubMed Central

    Brade, Carly J.; Dawson, Brian T.; Wallman, Karen E.

    2013-01-01

    Whether precooling is beneficial for exercise performance in warm climates when heat acclimatised is unclear. The purpose of this study was to determine the effect of precooling on repeat-sprint performance during a simulated team-sport circuit performed outdoors in warm, dry field conditions in seasonally acclimatised males (n = 10). They performed two trials, one with precooling (PC; ice slushy and cooling jacket) and another without (CONT). Trials began with a 30-min baseline/cooling period followed by an 80 min repeat-sprint protocol, comprising 4 x 20-min quarters, with 2 x 5-min quarter breaks and a 10-min half-time recovery/cooling period. A clear and substantial (negative; PC slower) effect was recorded for first quarter circuit time. Clear and trivial effects were recorded for overall circuit time, third and fourth quarter sprint times and fourth quarter best sprint time, otherwise unclear and trivial effects were recorded for remaining performance variables. Core temperature was moderately lower (Cohen's d=0.67; 90% CL=-1.27, 0.23) in PC at the end of the precooling period and quarter 1. No differences were found for mean skin temperature, heart rate, thermal sensation, or rating of perceived exertion, however, moderate Cohen's d effect sizes suggested a greater sweat loss in PC compared with CONT. In conclusion, repeat- sprint performance was neither clearly nor substantially improved in seasonally acclimatised players by using a combination of internal and external cooling methods prior to and during exercise performed in the field in warm, dry conditions. Of practical importance, precooling appears unnecessary for repeat-sprint performance if athletes are seasonally acclimatised or artificially acclimated to heat, as it provides no additional benefit. Key Points Pre-cooling did not improve repeated sprint performance during a prolonged team-sport circuit in field conditions. If individuals are already heat acclimatised/acclimated, pre-cooling is unnecessary for performance enhancement. Acclimation/acclimatisation seems to be the more powerful method for protecting against heat strain. PMID:24149166

  10. Radial growth response of white spruce ( Picea glauca) to climatic conditions, Mackenzie Delta, NWT

    NASA Astrophysics Data System (ADS)

    King, G. M.; Pisaric, M. F.; Kokelj, S. V.

    2007-12-01

    In Canada, 20th century air temperature warming has been greatest in the western Arctic.The prevailing theory of vegetation response to climate suggests warmer temperatures will result in increased growth of trees. However, a number of dendroecological studies from northwestern North America have highlighted a divergence in growth trends during recent decades. Several possible reasons for this response have been suggested. These include warmer temperatures that are exceeding the physiological threshold of white spruce, increased temperatures contributing to drought stress as precipitation is insufficient to offset increasing water demands or possibly large- scale processes such as changes in stratospheric ozone concentration or the effects of global dimming on photosynthetic rates. Here we document additional evidence for sites within the Mackenzie Delta showing a similar divergence trend with regional growing season temperatures. Additionally not all trees at a single site are responding similarly, with many more trees (~75%) having inverse climate-growth responses (negative responders). A much smaller subset continues to exhibit the traditional climate-growth response for treeline species - warmer temperatures equating to greater growth (positive responders). This study will investigate how environmental conditions influence tree growth within the Mackenzie Delta as the growing season progresses. Radial growth of white spruce trees is measured using automatic, high-resolution sensors (point dendrometers). These measurements are compared with environmental data (ground and air temperatures, precipitation, soil moisture, thaw layer depth and solar radiation) collected in-situ so that the critical factors associated with white spruce growth could be determined. The automatic growth sensors and environmental data were installed and monitored for two consecutive growing seasons at a site located north of Inuvik, NT. Tree cores were collected from 42 trees at the site including each of the instrumented trees to determine growth response over time. Measurements of active layer depth, tree health, competition and reproductive success were collected for each sampled tree to determine if any of these characteristics are related to the observed divergence with summer temperatures. This research has implications for the accurate modeling of future carbon sequestration rates within the boreal forest as well as accurate reconstruction of past climatic conditions and environments.

  11. Simulating potential effects of climatic warming on altitudinal patterns of key species in Mediterranean-alpine ecosystems

    Microsoft Academic Search

    Blas Benito; Juan Lorite; Julio Peñas

    2011-01-01

    In this paper we study an isolated high-mountain (Sierra Nevada, SE Iberian Peninsula) to identify the potential trends in\\u000a the habitat-suitability of five key species (i.e. species that domain a given vegetation type and drive the conditions for\\u000a appearance of many other species) corresponding to four vegetation types occupying different altitudinal belts, that might\\u000a result from a sudden climatic shift.

  12. Energy feedbacks of northern high-latitude ecosystems to the climate system due to reduced snow cover during 20th century warming

    USGS Publications Warehouse

    Euskirchen, E.S.; McGuire, A.D.; Chapin, F.S.

    2007-01-01

    The warming associated with changes in snow cover in northern high-latitude terrestrial regions represents an important energy feedback to the climate system. Here, we simulate snow cover-climate feedbacks (i.e. changes in snow cover on atmospheric heating) across the Pan-arctic over two distinct warming periods during the 20th century, 1910-1940 and 1970-2000. We offer evidence that increases in snow cover-climate feedbacks during 1970-2000 were nearly three times larger than during 1910-1940 because the recent snow-cover change occurred in spring, when radiation load is highest, rather than in autumn. Based on linear regression analysis, we also detected a greater sensitivity of snow cover-climate feedbacks to temperature trends during the more recent time period. Pan-arctic vegetation types differed substantially in snow cover-climate feedbacks. Those with a high seasonal contrast in albedo, such as tundra, showed much larger changes in atmospheric heating than did those with a low seasonal contrast in albedo, such as forests, even if the changes in snow-cover duration were similar across the vegetation types. These changes in energy exchange warrant careful consideration in studies of climate change, particularly with respect to associated shifts in vegetation between forests, grasslands, and tundra. ?? 2007 Blackwell Publishing Ltd.

  13. Global Warming: Frequently Asked Questions

    NSDL National Science Digital Library

    David Easterling

    This global warming site contains questions commonly addressed to climate scientists and brief replies (based on the Intergovernmental Panel on Climate Change (IPCC) reports and other research). The questions concern the greenhouse effect and its impact on our climate, whether greenhouse gases are increasing and the climate warming, the relation of El Nino to global warming, change in the hydrological cycle (evaporation and precipitation) and atmospheric/oceanic circulation, climate becoming more variable and extreme, the importance of these changes in a longer-term context, the rise of sea levels, whether the observed changes can be explained by natural variability, and the future of global warming.

  14. Mountain pine beetle develops an unprecedented summer generation in response to climate warming.

    PubMed

    Mitton, Jeffry B; Ferrenberg, Scott M

    2012-05-01

    The mountain pine beetle (MPB; Dendroctonus ponderosae) is native to western North America, attacks most trees of the genus Pinus, and periodically erupts in epidemics. The current epidemic of the MPB is an order of magnitude larger than any previously recorded, reaching trees at higher elevation and latitude than ever before. Here we show that after 2 decades of air-temperature increases in the Colorado Front Range, the MPB flight season begins more than 1 month earlier than and is approximately twice as long as the historically reported season. We also report, for the first time, that the life cycle in some broods has increased from one to two generations per year. Because MPBs do not diapause and their development is controlled by temperature, they are responding to climate change through faster development. The expansion of the MPB into previously inhospitable environments, combined with the measured ability to increase reproductive output in such locations, indicates that the MPB is tracking climate change, exacerbating the current epidemic. PMID:22504550

  15. Design and performance of combined infrared canopy and belowground warming in the B4WarmED (Boreal Forest Warming at an Ecotone in Danger) experiment.

    PubMed

    Rich, Roy L; Stefanski, Artur; Montgomery, Rebecca A; Hobbie, Sarah E; Kimball, Bruce A; Reich, Peter B

    2015-06-01

    Conducting manipulative climate change experiments in complex vegetation is challenging, given considerable temporal and spatial heterogeneity. One specific challenge involves warming of both plants and soils to depth. We describe the design and performance of an open-air warming experiment called Boreal Forest Warming at an Ecotone in Danger (B4WarmED) that addresses the potential for projected climate warming to alter tree function, species composition, and ecosystem processes at the boreal-temperate ecotone. The experiment includes two forested sites in northern Minnesota, USA, with plots in both open (recently clear-cut) and closed canopy habitats, where seedlings of 11 tree species were planted into native ground vegetation. Treatments include three target levels of plant canopy and soil warming (ambient, +1.7 °C, +3.4 °C). Warming was achieved by independent feedback control of voltage input to aboveground infrared heaters and belowground buried resistance heating cables in each of 72-7.0 m(2) plots. The treatments emulated patterns of observed diurnal, seasonal, and annual temperatures but with superimposed warming. For the 2009 to 2011 field seasons, we achieved temperature elevations near our targets with growing season overall mean differences (?Tbelow ) of +1.84 °C and +3.66 °C at 10 cm soil depth and (?T(above) ) of +1.82 °C and +3.45 °C for the plant canopies. We also achieved measured soil warming to at least 1 m depth. Aboveground treatment stability and control were better during nighttime than daytime and in closed vs. open canopy sites in part due to calmer conditions. Heating efficacy in open canopy areas was reduced with increasing canopy complexity and size. Results of this study suggest the warming approach is scalable: it should work well in small-statured vegetation such as grasslands, desert, agricultural crops, and tree saplings (<5 m tall). PMID:25640748

  16. Climate change in Canadian forests: Effect of global warming and CO2 fertilization on natural populations of black and white spruce

    NASA Astrophysics Data System (ADS)

    Nelson, E. A.; Thomas, S. C.

    2007-12-01

    Global increases in temperature and atmospheric CO2 concentration are predicted to enhance tree growth in the short term, but studies of current impacts of climate change on Canada's forests are limited. This study examined the effects of increasing temperature and atmospheric CO2 concentration on tree ring growth in west-central Manitoba and northern Ontario, sampling white spruce (Picea glauca) and black spruce (Picea mariana), respectively. Over 50 tree cores from each site were sampled, analysed for ring-width, cross-dated and detrended, generating a ~100 y chronology for each population. We found a positive correlation between ring-width increment and spring temperatures (April-May: p<0.005) in Ontario. In Manitoba, however, we found a negative correlation between summer temperatures (Jul-Aug: p<0.005) and ring-width increment coincident with a positive relationship with summer precipitation (July: p<0.03). We examined the residuals following a regression with temperature for a positive trend over time, which has been interpreted in prior studies as evidence for a CO2 fertilization effect. We detected no such putative CO2 fertilization signal in either spruce population. Our results suggest that temperature-limited lowland black spruce communities may respond positively to moderate warming, but that water-limited upland white spruce communities may suffer from drought stress under high temperature conditions. Neither population appears to benefit from increasing CO2 availability.

  17. Land–Ocean Warming Contrast over a Wide Range of Climates: Convective Quasi-Equilibrium Theory and Idealized Simulations

    E-print Network

    Byrne, Michael Patrick

    Surface temperatures increase at a greater rate over land than ocean in simulations and observations of global warming. It has previously been proposed that this land–ocean warming contrast is related to different changes ...

  18. Changes in Tree Phenology: an Indicator of Spring Warming in Ireland?

    Microsoft Academic Search

    Alison Donnelly; Nicolas Salamin; Mike B. Jones

    2006-01-01

    Recent climate warming has been observed at the global scale, but by examining developmental stages of plant species (phenology) that are dependent on local climatic conditions, climate change at the local scale can be detected. There are four gardens in Ireland belonging to the International Phenological Gardens (IPG) network, which has recorded tree phenology for more than 30 years using

  19. Methane emission from Russian frozen wetlands under conditions of climate change

    NASA Astrophysics Data System (ADS)

    Reneva, S.

    2009-04-01

    There is growing evidence that the climate change will have significant impact on permafrost, leading to warming, thawing, and disappearance of the frozen ground. Arctic soils contain 14%-30% of all the carbon stored in soils worldwide, many of which is accumulated in the Arctic wetlands (Anisimov & Reneva 2006). Wetlands occupy almost 2 million km2 in the circumpolar region, contain about 50 Gt C, and because of the high groundwater levels favour the production of methane in the anaerobic carbon-rich soil layer (Anisimov et al 2005). Methane has 21-times stronger greenhouse effect than the equal amount of CO2, and there are growing concerns that enhanced CH4 emission may have significant effect on the global radiative forcing. The goal of our study was to estimate the potential increase in the methane emission from Russian frozen wetlands under the projected for the mid-21st century climatic conditions and to evaluate the effect it may have on global radiative forcing. We used digital geographically referenced contours of Russian wetlands from 1:1,000,000-scale topographic maps to calculate the total area (350 000 km2) and the fraction of land they occupy in the nodes of 0.5 by 0.5 degree lat/long regular grid spanning permafrost regions. These data were overlaid with the results from predictive permafrost model (Anisimov & Belolutskaia 2003, Anisimov et al 1999) forced by CCC, HadCM3, GFDL, NCAR climatic projections for 2050 under B1 emission scenario (ref. http://ipcc-ddc.cru.uea.ac.uk/ and http://igloo.atmos.uiuc.edu/IPCC/). Ultimately, we calculated the increase in the amount of organic material that may potentially become available for decomposition due to deeper seasonal thawing of wetlands in the Russian part of Arctic. Following (Christensen et al 2003a, Christensen et al 2003b) we hypothesised that the temperature and substrate availability combined explain almost entirely the variations in mean annual methane emissions. We used the results of numerous calculations with the full-scale carbon model simulating a large variety of soil and temperature conditions to derive a simple parameterization that links the relative changes of methane flux with soil temperature and active layer thickness: J2/J1= exp 0.1(T2 - T1) , where J - methane flux, T - ground temperature, Hd - thaw depth, subscripts 1 and 2 designate the baseline and future climatic conditions current and the future time slices. Our results for the mid-21stcentury indicate that the annual emission of methane from Russian permafrost region may increase by 20% - 40% over most of the area, and by 50% - 80% in the northernmost locations, which corresponds to 6-8 Mt y-1. Given that the average residence time of methane in the atmosphere is 12 years, and assuming that other sinks and sources remain unchanged, by the mid-21st century the additional annual 6-8 Mt source due to thawing of permafrost may increase the overall amount of atmospheric methane by approximately 100 Mt, or 0.04 ppm. The sensitivity of the global temperature to 1 ppm of atmospheric methane is approximately 0.3 oC (Ramaswamy 2001), and thus the additional radiative forcing resulting from such an increase may raise the global mean annual air temperature by 0.012 oC. References Anisimov OA, Belolutskaia MA. 2003. Climate-change impacts on permafrost: predictive modeling and uncertainties. In Problems of ecological modeling and monitoring of ecosystems, ed. Y Izrael, pp. 21-38. S.Petersburg: Hydrometeoizdat Anisimov OA, Lavrov SA, Reneva SA. 2005. Modelling the emission of greenhouse gases from the Arctic wetlands under the conditions of the global warming. In Climatic and environmental changes, ed. GV Menzhulin, pp. 21-39. S.Petersburg: Hydrometeoizdat Anisimov OA, Nelson FE, Pavlov AV. 1999. Predictive scenarios of permafrost development under the conditions of the global climate change in the XXI century. Earth Cryosphere 3: 15-25 Anisimov OA, Reneva SA. 2006. Permafrost and changing climate: the Russian perspective. Ambio 35: 169-75 Christensen TR, Ekberg A, Strom L, Mastepanov M,

  20. Climate warming and the potential extinction of fig wasps, the obligate pollinators of figs.

    PubMed

    Jevanandam, Nanthinee; Goh, Alexander G R; Corlett, Richard T

    2013-06-23

    Figs (Ficus) have a reciprocally obligate mutualism with tiny, short-lived (1-2 days) fig wasps (Agaonidae). The small size and short life of these pollinators is expected to make them more vulnerable to climate change than their larger and longer-lived hosts. We experimentally tested the thermal tolerances of four species of adult female fig wasp from equatorial Singapore. The results suggest that an increase of 3°C or more above the current temperatures experienced across much of the equatorial tropics would markedly decrease the active adult lifespan of all four species. Fig plants are the centre of an intricate web of specialist and generalist animals. Unless fig wasps can acclimate or adapt to warmer temperatures in time, these responses may disrupt the mutualism, potentially affecting multiple trophic levels. PMID:23515979

  1. Climate warming and the potential extinction of fig wasps, the obligate pollinators of figs

    PubMed Central

    Jevanandam, Nanthinee; Goh, Alexander G. R.; Corlett, Richard T.

    2013-01-01

    Figs (Ficus) have a reciprocally obligate mutualism with tiny, short-lived (1–2 days) fig wasps (Agaonidae). The small size and short life of these pollinators is expected to make them more vulnerable to climate change than their larger and longer-lived hosts. We experimentally tested the thermal tolerances of four species of adult female fig wasp from equatorial Singapore. The results suggest that an increase of 3°C or more above the current temperatures experienced across much of the equatorial tropics would markedly decrease the active adult lifespan of all four species. Fig plants are the centre of an intricate web of specialist and generalist animals. Unless fig wasps can acclimate or adapt to warmer temperatures in time, these responses may disrupt the mutualism, potentially affecting multiple trophic levels. PMID:23515979

  2. Snow surface energy and mass balance in a warm temperate climate mountain

    NASA Astrophysics Data System (ADS)

    Sade, Rotem; Rimmer, Alon; Litaor, M. Iggy; Shamir, Eylon; Furman, Alex

    2014-11-01

    In warm temperate mountain regions where water is often scarce vapor losses from the snow-surface can substantially limit snowmelt. Therefore, understanding the key snow dynamic processes that affect water availability in these mountains is essential. We studied the snowpack energy and mass balance in Mt. Hermon, Israel using a comprehensive field campaign during 2010/11. We analyzed the snowpack energy and mass balance during the winter of 2010/11 in a Deep Snow Patch (DSP), and in the Bulan valley experiment area (BVEA), where both windswept locations and lee-side (deep snowpack) locations were examined. We applied for this analysis an energy and mass balance snow model that was forced by input from two meteorological stations. The calibration of the model for the DSP and BVEA was based on surveyed snow water equivalent data, and melting cycles that were measured with time-lapse cameras, respectively. Using a step function to describe wind speed over the DSP we showed that the turbulent fluxes were influenced by changes in snowpack height. The turbulent fluxes were found as the dominant energy fluxes at the snow-surface. During winter, vapor losses varied between 46% and 82% of the total ablation. Consequently, latent heat flux consumed much of the available energy at the snow-surface, greatly limiting melting rate to 1 mm day-1. During spring, vapor flux was positive which enhanced condensation, resulting in an average melting flux of 86 mm day-1. The spatial variation in the vapor flux at the BVEA due to terrain orientation yield variation in space of the available water at the bottom of the snowpack.

  3. Influence of Grape Composition on Red Wine Ester Profile: Comparison between Cabernet Sauvignon and Shiraz Cultivars from Australian Warm Climate.

    PubMed

    Antalick, Guillaume; Šuklje, Katja; Blackman, John W; Meeks, Campbell; Deloire, Alain; Schmidtke, Leigh M

    2015-05-13

    The relationship between grape composition and subsequent red wine ester profile was examined. Cabernet Sauvignon and Shiraz, from the same Australian very warm climate vineyard, were harvested at two different stages of maturity and triplicate wines were vinified. Grape analyses focused on nitrogen and lipid composition by measuring 18 amino acids by HPLC-FLD, 3 polyunsaturated fatty acids, and 6 C6-compounds derived from lipid degradation by GC-MS. Twenty esters and four higher alcohols were analyzed in wines by HS-SPME-GC-MS. Concentrations of the ethyl esters of branched acids were significantly affected by grape maturity, but the variations were inconsistent between cultivars. Small relative variations were observed between wines for ethyl esters of fatty acids, whereas higher alcohol acetates displayed the most obvious differences with concentrations ranging from 1.5- to 26-fold higher in Shiraz than in Cabernet Sauvignon wines regardless of the grape maturity. Grape analyses revealed the variations of wine ester composition might be related to specific grape juice nitrogen composition and lipid metabolism. To the authors' knowledge the present study is the first to investigate varietal differences in the ester profiles of Shiraz and Cabernet Sauvignon wines made with grapes harvested at different maturity stages. PMID:25905977

  4. Climate Change: Basic Information

    MedlinePLUS

    ... now. Learn More What are climate change and global warming? Global warming refers to the recent and ongoing rise in ... increasing concentrations of greenhouse gases in the atmosphere. Global warming is causing climate patterns to change. However, global ...

  5. Observed changes of the precipitation spectrum structure over China in a warming climate

    NASA Astrophysics Data System (ADS)

    Ma, Shuangmei; Zhou, Tianjun; Dai, Aiguo; Han, Zhenyu

    2015-04-01

    In this study, the changes in the spectrum structure of the precipitation (the probability distribution function of precipitation frequency and accumulated amount as a function of precipitation intensity category) over China and its six sub-regions during 1960-2013 are analyzed using homogenized daily rain gauge data from 632 stations. The spectrum structure of the precipitation has shifted from less light precipitation events to more very heavy precipitation events in the past half century over China. For whole China area weighted mean, very heavy precipitation events increased significantly with the rate 1.51% per decade. Meanwhile, the decrease of light (-1.25% per decade) and moderate (-1.14% per decade) precipitation events is also significant. Moreover, dry days and trace days showed increase of 3.78% per decade and decrease of -8.22% per decade, both trend are statistically significant at the 0.001 level. The above shifts of precipitation spectrum structure imply an increase of the risk of drought and flood over China in the past half century. Although the consistently significant increase of dry days and decrease of light precipitation, trace days and total precipitation days are almost throughout whole China, changes in other precipitation intensity grades exhibited obvious regional characteristics. Over Yangtze River valley (YZ) and South China (SC), very heavy precipitation events also increased at the expense of light precipitation. However, positive trends dominated the changes in precipitation spectrum structure of Northwest China (NC); precipitation spectrum structure showed an overall weakening over Southwest China (SC) and North China (NC), and an overall strengthening in Northeast China (NE). We examined the dependence of the precipitation spectrum structure change over China on global temperature based on method proposed by Liu et al., (2009), results showed that extreme weak and extreme high precipitation events are more easily affected by global warming than medium intensity precipitation events. For a 1K increase of global temperature, national averaged dry days increase 20.63%; trace days and total precipitation events decrease 46.53% and 22.89%, respectively; the extreme weak (lowest 10% bin) and high (top 10% bin) precipitation showed large decrease and increase of -27.12% and 24.21%, separately.

  6. Present-day climatology and projected changes of warm and cold days in the CNRM-CM3 global climate model

    Microsoft Academic Search

    J. Ballester; H. Douville; F. Chauvin

    2009-01-01

    The impact of global warming on the warmest and coldest days of the annual cycle is explored according to an A2 scenario simulated\\u000a by the CNRM-CM3 climate model in the framework of the IPCC AR4 intercomparison. Given the multi-model spread in IPCC projections,\\u000a a validation strategy is proposed using the NCEP\\/NCAR reanalysis. Validation of the late twentieth century model climatology

  7. How do you say 'Global Warming' in Your Language?" Linguistic Research on Climate Change in the Upper Tanana Valley, Alaska

    NASA Astrophysics Data System (ADS)

    Lovick, O.

    2006-12-01

    The Upper Tanana valley in the interior of Alaska used to be one of the most remote regions on the North American continent. This changed rapidly about 100 years ago, with the onset of the gold rush. Ever since, change has come to the Upper Tanana valley in many forms, from the intrusion of white people to climate change and pollution. The changes are severe and on-going, and they affect everyday life in every possible way. It is obvious that the ideal consultant for long-term studies like studies on climate change has to be older rather than younger. In rural communities of Alaska, including the ones targeted in this study, older consultants, that is, consultants in their 60s or older, usually have a first language different from English, in our case Upper Tanana Athabascan. Even though most of these consultants do have some knowledge of English, their skills in this language can be limited. Thus, communication between the (English-speaking) scientist and the (Upper Tanana-speaking) consultant is bound to be problematic and error-prone. This can be avoided by conducting the research in the Native language. This poster illustrates as part of IPY research how the kinds of change mentioned above are regarded by the Upper Tanana Athabascans, and how the Upper Tanana language reflects them. Concepts like 'global warming' or 'greenhouse effect' are relatively new even to the English language. Speakers are asked to translate such and similar terms into their language, and to explain their choice of words. While the Upper Tanana translations of these terms do not necessarily reflect the English original accurately, discussion of such concepts is still possible for a fluent speaker. Still, the ways of expression such concepts differ from language to language, a different pool of metaphors is employed in the formation of words, and there are nuances in Upper Tanana that can easily get lost in translation to English. Thus, the use of the Upper Tanana language reflects to some degree the Upper Tanana views on climate change. Additionally, scientific interpretations are very much affected by more accurate translations and by less misapprehension of Upper Tanana concepts.

  8. Scaling and trends of hourly precipitation extremes in a warming climate

    NASA Astrophysics Data System (ADS)

    Lenderink, G.; van Oldenborgh, G. J.; Attema, J. J.

    2012-04-01

    Hourly precipitation extremes in very long time series from the Hong Kong Observatory and the Netherlands are investigated. Using the 2 m dew point temperature from 4 h before the rainfall event as a measure of near surface absolute humidity, hourly precipitation extremes closely follow a 14 % per degree dependency - a scaling twice as large as following from the Clausius-Clapeyron relation. However, for dew point temperatures above 23 °C no significant dependency on humidity was found. Strikingly, in spite of the large difference in climate, results are almost identical in Hong Kong and the Netherlands for the dew point temperature range where both observational sets have sufficient data. Trends in hourly precipitation extremes show substantial increases over the last century for both De Bilt (the Netherlands) and Hong Kong. For De Bilt, not only the long term trend, but also variations in hourly precipitation extremes on a inter-decadal timescale of 30 yr and longer, can be linked very well to the above scaling; there is a very close resemblance between variations in dew point temperature and precipitation intensity with an inferred dependency of hourly precipitation extremes of 10 to 14 % per degree.

  9. Mechanisms for Annual Cycle Changes in Monsoons in a Warming Climate

    NASA Astrophysics Data System (ADS)

    Seth, Anji

    2014-05-01

    Analyses of phase 5 of the Coupled Model Intercomparison Project (CMIP5) experiments show that the global monsoon is expected to increase in area, precipitation, and intensity as the climate system responds to anthropogenic forcing. Concurrently, detailed analyses for several individual monsoons indicate a re-distribution of rainfall from early to late in the rainy season. This presentation will further examine CMIP5 projected changes in the annual cycle of precipitation in monsoon regions, and use a moist static energy framework to evaluate competing mechanisms identified to be important in precipitation changes over land. In the presence of sufficient surface moisture, the local response to the increase in downwelling energy is characterized by increased evaporation, increased low-level moist static energy, and decreased stability with consequent increases in precipitation. A remote mechanism begins with warmer oceans and operates on land regions via a warmer tropical troposphere, increased stability, and decreased precipitation. The remote mechanism controls the projected changes during winter, and the local mechanism appears to control the switch to increased precipitation during summer in several monsoon regions. During the early summer transition, regions where boundary layer moisture availability is reduced due to decreases in evaporation and moisture convergence experience an enhanced convective barrier. This enhanced convective barrier leads to a redistribution of rainfall from early to late summer, and is robust in the American and African monsoons but not seen in Asia.

  10. Magnitude of extreme heat waves in present climate and their projection in a warming world

    NASA Astrophysics Data System (ADS)

    Russo, Simone; Dosio, Alessandro; Graversen, Rune G.; Sillmann, Jana; Carrao, Hugo; Dunbar, Martha B.; Singleton, Andrew; Montagna, Paolo; Barbola, Paulo; Vogt, Jürgen V.

    2014-11-01

    An extreme heat wave occurred in Russia in the summer of 2010. It had serious impacts on humans and natural ecosystems, it was the strongest recorded globally in recent decades and exceeded in amplitude and spatial extent the previous hottest European summer in 2003. Earlier studies have not succeeded in comparing the magnitude of heat waves across continents and in time. This study introduces a new Heat Wave Magnitude Index that can be compared over space and time. The index is based on the analysis of daily maximum temperature in order to classify the strongest heat waves that occurred worldwide during the three study periods 1980-1990, 1991-2001, and 2002-2012. In addition, multimodel ensemble outputs from the Coupled Model Intercomparison Project Phase 5 are used to project future occurrence and severity of heat waves, under different Representative Concentration Pathways, adopted by the Intergovernmental Panel on Climate Change for its Fifth Assessment Report (AR5). Results show that the percentage of global area affected by heat waves has increased in recent decades. Moreover, model predictions reveal an increase in the probability of occurrence of extreme and very extreme heat waves in the coming years, in particular, by the end of this century, under the most severe IPCC AR5 scenario, events of the same severity as that in Russia in the summer of 2010 will become the norm and are projected to occur as often as every 2 years for regions such as southern Europe, North America, South America, Africa, and Indonesia.

  11. Juniperus communis: victim of the combined action of climate warming and nitrogen deposition?

    PubMed

    Verheyen, K; Adriaenssens, S; Gruwez, R; Michalczyk, I M; Ward, L K; Rosseel, Y; Van den Broeck, A; García, D

    2009-11-01

    Research on the combined effects of climate change and nitrogen deposition on reproductive traits, and especially on the production of viable seeds, is still scarce despite their importance for population persistence and expansion. Hence, in this study we set out to investigate the direct and indirect effects of the above-mentioned global change drivers on seed viability in the coniferous shrub Juniperus communis L. In many parts of its European range, juniper is increasingly threatened, partly because of a lack of sexual reproduction. We hypothesised that this regeneration failure is partly due to poor seed viability. Using data from 39 populations throughout Europe, we were able to demonstrate that a strong, triangular-shaped relationship exists between the percentage of viable seeds produced and the percentage of juniper seedlings occurring in a population, which indicates that the species is indeed partly seed limited. Furthermore, based on an extended dataset of 42 populations, we found that seed viability was negatively affected by temperature, measured as mean annual growing degree-days, and nitrogen deposition (but not by drought). Suggestions are made about the processes behind the observed patterns, but more research is required. Nevertheless, our results do raise serious concerns for the conservation of juniper in light of the predicted rise in temperature and global nitrogen emissions. Furthermore, it is likely that similar patterns can also be observed for other species. PMID:19778368

  12. Changes in nutrient retention capacity of boreal aquatic ecosystems under climate warming: a simulation study

    Microsoft Academic Search

    Paula Kankaala; Anne Ojala; Tiina Tulonen; Lauri Arvola

    2002-01-01

    Loading, retention and release of nitrogen and phosphorus were studied for three growing seasons in experimental flow-through pond ecosystems, where impacts of rising temperature on the boreal zone were studied; one pond was under ambient temperature conditions and another was enclosed in a greenhouse with air temperature 2–3 °C higher than ambient. The ponds received a high load of nitrogen

  13. [Changes of China agricultural climate resources under the background of climate change. IV. Spatiotemporal change characteristics of agricultural climate resources in sub-humid warm-temperate irrigated wheat-maize agricultural area of Huang-Huai-Hai Plain].

    PubMed

    Liu, Zhi-juan; Yang, Xiao-guang; Wang, Wen-feng

    2011-04-01

    Based on the 1961-2007 observation data from 66 meteorological stations in the sub-humid and warm-temperate irrigated wheat-maize agricultural area of Huang-Huai-Hai Plain, this paper analyzed the spatiotemporal change characteristics of agro-climate resources for chimonophilous and thermophilic crops in the area in 1961-1980 and 1981-2007. The analyzed items included the length of temperature-defined growth season and the active accumulative temperature, sunshine hours, precipitation, reference evapotranspiration, and aridity index during the temperature-defined growth season. With climate warming, the length of temperature-defined growth season of chimonophilous and thermophilic crops in the area in 1981-2007 extended by 7. 4 d and 6. 9 d, and the > or = 0 degrees C and > or = 10 degrees C accumulative temperature increased at a rate of 4.0-137.0 and 1.0-142.0 degrees C d (10 a)(-1), respectively, compared with those in 1961-1980. The sunshine hours during the temperature-defined growth season of the crops decreased markedly; and the precipitation during the temperature-defined growing season decreased in most parts of the area, being obvious in Hebei and north Shandong Province, but increased in north Anhui and southeast Henan Province. In most parts of the area, the reference evapotranspiration of chimonophilous and thermophilic crops during their temperature-defined growth season decreased, and the aridity index increased. PMID:21774311

  14. Climate Change and Flood Operations in the Sacramento Basin, California

    E-print Network

    Schladow, S. Geoffrey

    #12;JULY 2011 Climate Change and Flood Operations in the Sacramento Basin, California Ann D. Willis operating rules is an important adaptation for climate warming. KEY WORDS Climate change, flood control with changing conditions. A changing climate, along with other changes in floodplain land use and flood warn

  15. What is Global Warming?

    NSDL National Science Digital Library

    2012-09-28

    This textbook chapter presents evidence of a warming climate and outlines how a clear picture of global warming has emerged since the 1980s. Students learn about sampling error sources in climate data, and compare graphical data collected by climate scientists Jim Hansen, Philip Jones and Tom Wigley, as they follow the global warming hypothesis move through the process of science. This is the fourth chapter in the unit, Climate Change, which addresses the question of how human activities are changing Earth's climate. The resource includes three classroom investigations, links to current news articles, and a suite of pre- and post-unit assessments. A teacher's guide supports classroom use. This is chapter 4 of Climate Change, part of Global Systems Science (GSS), an interdisciplinary course for high school students that emphasizes how scientists from a wide variety of fields work together to understand significant problems of global impact.

  16. Drug formulations intended for the global market should be tested for stability under tropical climatic conditions

    Microsoft Academic Search

    P. G. Risha; C. Vervaet; G. Vergote; L. Van Bortel; J. P. Remon

    2003-01-01

    Rationale. Objective. The quality of drugs imported into developing countries having a tropical climate may be adversely affected if their formulations have not been optimized for stability under these conditions. The present study investigated the influence of tropical climate conditions (class IV: 40°C, 75% relative humidity) on the drug content, in vitro dissolution and oral bioavailability of different formulations of

  17. Potential transition from seasonal to ephemeral snow in Great Lakes watersheds in a warming climate

    NASA Astrophysics Data System (ADS)

    Durand, M. T.; Rine, M.

    2013-12-01

    Snow cover in many regions is a primary contributor to the hydrologic cycle and has significant surface energy balance, biogeochemical, ecological, and societal impacts. This study uses weather stations in Canada (using Environment Canada (EC) data) and the United States (using the Midwest Regional Climate Center (MRCC) data) to characterize climatological snow cover in the Great Lakes basins, and its sensitivity to future winter temperature increases. Much of this region is dominated by an ephemeral snow cover, where snow comes and goes throughout the winter months, having no significant seasonal duration. We defined "expected duration" as the uninterrupted number of days with snow cover on the ground in a typical winter. The number of days of snow cover (as opposed to the expected duration) are also analyzed; the expected duration is a better metric of whether a snowcover is ephemeral or seasonal, since it ties more directly to snowpack residence times and seasonality of runoff. We estimated the snowcover expected duration at 448 weather stations throughout the Great Lakes basins. We defined ephemeral snowcover to have an expected duration of 60 days or greater per winter, which corresponds to a latitude north of approximately 44°, in this area. We found that average winter temperature can be used to predict duration of snowcover expected duration, to first order. The ephemeral snow line in the Great Lakes basins corresponds to an average winter temperature of approximately -4 to -5° C. The statistical model relating snowcover expected duration and average winter air temperature indicates approximately a 22 day decrease in snowcover expected duration with an increase of 2° degree C. This estimate of duration sensitivity to temperature was used to identify seasonal and ephemeral watershed changes for 2° C increase in temperature. Our analysis shows that approximately 25 percent of the snow cover in the Great Lakes Basins will shift from a seasonal to an ephemeral snow pack with a 2° temperature increase. At time of writing, this sensitivity was determined from stations only the MRCC; future work will include analysis these trends using both EC and MRCC data. We map the the seasonal snow at risk of an ephemeral transition, and break down the likely affects by basin. Lake Eries and Ontario are currently ephemeral snow, and would be relatively unaffected by a 2° change. We found there is not a risk of an ephemeral transition for Lake Superior, but there is a risk for Lakes Michigan and Huron, and for watersheds draining directly to the St. Lawrence.

  18. Nonglacial rapid climate events: past and future.

    PubMed

    Overpeck, J; Webb, R

    2000-02-15

    The paleoclimate record makes it clear that rapid climate shifts of the 20th century are only a subset of possible climate system behavior that might occur in the absence of glacial conditions, and that climatic surprises could be a challenge for society even in the absence of significant greenhouse warming. PMID:10677461

  19. Pleistocene calcrete deposits from southern Spain as indicators of climatic conditions and tectonic activity

    NASA Astrophysics Data System (ADS)

    Herrero, Maria J.; Insua-Arevalo, Juan M.; Garcia-Mayordomo, Julian; Martin-Banda, Raquel

    2014-05-01

    Quaternary calcrete horizons are common weathering products in arid and semi-arid regions of southern Spain. We have analysed a calcrete profile developed within poorly sorted gravels of an alluvial fan. These deposits were sourced from the Carrascoy Range, a fault generated mountain front located in the Internal Zones of the Betic Cordillera (South Spain). During the Pleistocene the climate in southern Spain was dry, either in the form of semi-arid/arid conditions or as seasonal moisture deficits. Alluvial channel incision trends appeared to be disrupted by episodes of alluvial aggradation produced during cold and dry glacial periods. At the top of the aggradational phases, pedogenic processes operated profusely, and, as a result, several calcretes (stage V mature calcrete profiles) were formed. We have analysed one of these calcrete profiles that appears subvertical within the forelimb of a regional fold in relation to the Carrascoy Fault activity. The calcrete consist of a densely cemented hardpan horizon (20 to 40 cm thick) overlain by a thin, 2-cm thick laminar crust. Below the hardpan horizon, carbonate concentrations gradually decrease to clast-coating textures. Calcretes form progressively and a wide range of carbonate phases occur within a single horizon, being the laminar crust the final stage of evolution within a mature pedogenic calcrete deposit, and, therefore, the carbonate within it postdates all the cement phases within the profile. The location of the latest cement phase of the calcrete deposit has been estimated by microscopic observations (to establish their suitability for dating) together with a detailed sedimentological analysis of the calcrete profile in the field. The laminar crust consists of less than 1 mm thick laminae characterized by the alternation of layers of micrite and layers of micrite with ooids, detrital grains and clays indicating environmental conditions in which sedimentation rates were low and episodic. By using radiometric 232Th/238U dating methods we obtain an age of formation of the laminar crust of ~209 Ka (upper part of the Middle Pleistocene). This age corresponds to the warm stage 7c within the glacial Riss period. As pointed out before, the studied calcrete appears subvertical as a result of the activity of the Carrascoy Fault, and, therefore, the fault was active only after the calcrete was formed. Our study permits, as well, to reliably asses the timing of changes in alluvial processes, to characterized this part of the stratigraphic succession as corresponding to an arid to semi-arid environment, and to conclude that this particular calcrete was developed during a relative European warm period within a glacial stage.

  20. LETSNet Global Warming Unit

    NSDL National Science Digital Library

    This unit includes classroom activities to help students understand global warming and its possible effects on human beings. Lessons in the unit provide students with opportunities to study global climate changes, discuss and debate the current arguments for and against global warming and the Greenhouse Effect, investigate the possibility of global warming and the Greenhouse Effect, and present their findings in the form of research reports.

  1. Reconciling Warming Trends

    NASA Technical Reports Server (NTRS)

    Schmidt, Gavin A.; Shindell, Drew T.; Tsigaridis, Konstantinos

    2014-01-01

    Climate models projected stronger warming over the past 15 years than has been seen in observations. Conspiring factors of errors in volcanic and solar inputs, representations of aerosols, and El NiNo evolution, may explain most of the discrepancy.

  2. Spectroscopics database for warm Xenon and Iron in Astrophysics and Laboratory Astrophysics conditions

    NASA Astrophysics Data System (ADS)

    Busquet, Michel; Klapisch, Marcel; Bar-Shalom, Avi; Oreg, Josse

    2010-11-01

    The main contribution to spectral properties of astrophysics mixtures come often from Iron. On the other hand, in the so-called domain of ``Laboratory Astrophysics,'' where astrophysics phenomena are scaled down to the laboratory, Xenon (and Argon) are commonly used gases. At so called ``warm'' temperatures (T=5-50eV), L-shell Iron and M-shell Xenon present a very large number of spectral lines, originating from billions of levels. More often than not, Local Thermodynamical Equilibrium is assumed, leading to noticeable simplification of the computation. Nevertheless, complex and powerful atomic structure codes are required. We take benefit of powerful statistics and numerics, included in our atomic structure codes, STA[1] and HULLAC[2], to generate the required spectra. Recent improvements in both fields (statistics, numerics and convergence control) allow obtaining large databases (ro x T grid of > 200x200 points, and > 10000 frequencies) for temperature down to a few eV. We plan to port these improvements in the NLTE code SCROLL[3]. [1] A.Bar-Shalom, et al, Phys. Rev. A 40, 3183 (1989) [2] M.Busquet,et al, J.Phys. IV France 133, 973-975 (2006); A.Bar-Shalom, M.Klapisch, J.Oreg, J.Oreg, JQSRT 71, 169, (2001) [3] A.Bar-Shalom, et al, Phys. Rev. E 56, R70 (1997)

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

    E-print Network

    (NAO) and the Arctic Oscillation (AO), which have shown trends towards the high index phase over in the positive phase of the Arctic Oscillation (AO), associated with higher-than-normal surface pressure south-level pressure over polar latitudes leads to a negative trend of the winter AO index. The model reproduces large

  4. Trends in atmospheric concentrations of weed pollen in the context of recent climate warming in Pozna? (Western Poland).

    PubMed

    Bogawski, Pawe?; Grewling, Lukasz; Nowak, Ma?gorzata; Smith, Matt; Jackowiak, Bogdan

    2014-10-01

    A significant increase in summer temperatures has been observed for the period 1996-2011 in Pozna?, Poland. The phenological response of four weed taxa, widely represented by anemophilous species (Artemisia spp., Rumex spp. and Poaceae and Urticaceae species) to this recent climate warming has been analysed in Pozna? by examining the variations in the course of airborne pollen seasons. Pollen data were collected by 7-day Hirst-type volumetric trap. Trends in pollen seasons were determined using Mann-Kendall test and Sen's slope estimator, whereas the relationships between meteorological and aerobiological data were established by Spearman's rank correlation coefficient. Significant trends in pollen data were detected. The duration of pollen seasons of all analysed taxa increased (from +2.0 days/year for Urticaceae to +3.8 days/year for Rumex), which can be attributed to a delay in pollen season end dates rather than earlier start dates. In addition, the intensity of Artemisia pollen seasons significantly decreased and correlates with mean July-September daily minimum temperatures (r =?-0.644, p < 0.01). In contrast, no significant correlations were found between temperature and characteristics of Rumex pollen seasons. The results of this study show that observed shifts in weed pollen seasons in Pozna?, i.e. longer duration and later end dates, might be caused by the recorded increase in summer temperature. This influence was the strongest in relation to Artemisia, which is the taxon that flowers latest in the year. The general lack of significant correlations between Rumex and Urticaceae pollen seasons and spring and/or summer temperature suggests that other factors, e.g. land use practices, could also be partially responsible for the observed shifts in pollen seasons. PMID:24402307

  5. The European land leech: biology and DNA-based taxonomy of a rare species that is threatened by climate warming.

    PubMed

    Kutschera, U; Pfeiffer, I; Ebermann, E

    2007-12-01

    The European land leech Xerobdella lecomtei was discovered in 1868 and is one of the rarest animals on Earth. During the 1960s, several individuals of these approx. 40 mm long, cold-adapted terrestrial annelids that inhabit the moist soils of birch forests around Graz, Austria, were investigated. Only one original research paper has been published on the biology of this species. Between 2001 and 2005, we re-investigated the morphology of preserved specimens and searched for living individuals in their natural habitat that appeared to be intact. We found only one juvenile individual (length approx. 10 mm), indicating that this local leech population became largely extinct over the past four decades. The feeding behaviour of our 'lonesome George of the annelids' was studied and is described here in detail. After its death, the Xerobdella individual was used for chemical extraction and molecular studies (deoxyribonucleic acid [DNA] barcoding, based on one gene, the mitochondrial cytochrome c oxidase subunit I). In addition, novel DNA barcodes for a land leech from Madagascar and a recently discovered species from Europe were obtained. Our phylogenetic tree shows that X. lecomtei is not a member of the tropical land leeches (family Haemadipsidae), as previously thought, but represents a separate line of descent (family Xerobdellidae). The decline of the local leech population around Graz correlates with a rise in average summer temperatures of +3 degrees C between 1961 and 2004. This warming led to a drastic reduction in the moisture content of the soil where X. lecomtei lives. We suggest that human-induced climate change without apparent habitat destruction can lead to the extinction of populations of cold-adapted species that have a low colonization ability. PMID:17646954

  6. Trends in atmospheric concentrations of weed pollen in the context of recent climate warming in Pozna? (Western Poland)

    NASA Astrophysics Data System (ADS)

    Bogawski, Pawe?; Grewling, ?ukasz; Nowak, Ma?gorzata; Smith, Matt; Jackowiak, Bogdan

    2014-10-01

    A significant increase in summer temperatures has been observed for the period 1996-2011 in Pozna?, Poland. The phenological response of four weed taxa, widely represented by anemophilous species ( Artemisia spp., Rumex spp. and Poaceae and Urticaceae species) to this recent climate warming has been analysed in Pozna? by examining the variations in the course of airborne pollen seasons. Pollen data were collected by 7-day Hirst-type volumetric trap. Trends in pollen seasons were determined using Mann-Kendall test and Sen's slope estimator, whereas the relationships between meteorological and aerobiological data were established by Spearman's rank correlation coefficient. Significant trends in pollen data were detected. The duration of pollen seasons of all analysed taxa increased (from +2.0 days/year for Urticaceae to +3.8 days/year for Rumex), which can be attributed to a delay in pollen season end dates rather than earlier start dates. In addition, the intensity of Artemisia pollen seasons significantly decreased and correlates with mean July-September daily minimum temperatures ( r = -0.644, p < 0.01). In contrast, no significant correlations were found between temperature and characteristics of Rumex pollen seasons. The results of this study show that observed shifts in weed pollen seasons in Pozna?, i.e. longer duration and later end dates, might be caused by the recorded increase in summer temperature. This influence was the strongest in relation to Artemisia, which is the taxon that flowers latest in the year. The general lack of significant correlations between Rumex and Urticaceae pollen seasons and spring and/or summer temperature suggests that other factors, e.g. land use practices, could also be partially responsible for the observed shifts in pollen seasons.

  7. Change in bedload transport frequency with climate warming in gravel-bed streams of the Oregon Cascades

    NASA Astrophysics Data System (ADS)

    Hempel, L. A.; Grant, G.; Lewis, S.; Safeeq, M.

    2014-12-01

    Previous modeling studies have predicted that high flows in the Oregon Cascades will become larger and shift towards earlier in the winter season with climate warming. The impact of those changes on bedload transport frequency and channel morphology remains unknown, however. We examined changes in the timing and magnitude of bedload transport under modeled flow scenarios to identify which rivers draining the Cascades with different hydrologic regimes are most vulnerable to increased frequency of bedload transport. Such increases in the frequency or magnitude of gravel entrainment might lead to disturbance of fragile salmon or bull trout habitat. We calculated bedload transport rates using field measurements of surface sediment size, channel geometry, and channel slope along 14 reaches that included streams with a range of drainage areas and flow regimes (i.e., spring-fed and surface-runoff dominated). Our findings suggest that both spring-fed and surface-runoff streams are vulnerable to predicted changes in the flow regime, but in different ways. Spring-fed streams, characterized by relatively uniform discharge, will likely experience changes in both the timing and magnitude of transport. Spring-fed streams are poised just above the critical transport threshold for a large portion of the year, therefore small changes in the highest flows may lead to marked changes in transport rates. Transport events in surface-runoff streams, which are already characterized by flashy flows, will likely become larger and more frequent. Changes in the frequency and timing of bedload transport in both spring-fed and surface runoff streams will impact bed stability and texture and should be considered for managing these watersheds in the future.

  8. The European land leech: biology and DNA-based taxonomy of a rare species that is threatened by climate warming

    NASA Astrophysics Data System (ADS)

    Kutschera, U.; Pfeiffer, I.; Ebermann, E.

    2007-12-01

    The European land leech Xerobdella lecomtei was discovered in 1868 and is one of the rarest animals on Earth. During the 1960s, several individuals of these approx. 40 mm long, cold-adapted terrestrial annelids that inhabit the moist soils of birch forests around Graz, Austria, were investigated. Only one original research paper has been published on the biology of this species. Between 2001 and 2005, we re-investigated the morphology of preserved specimens and searched for living individuals in their natural habitat that appeared to be intact. We found only one juvenile individual (length approx. 10 mm), indicating that this local leech population became largely extinct over the past four decades. The feeding behaviour of our ‘lonesome George of the annelids’ was studied and is described here in detail. After its death, the Xerobdella individual was used for chemical extraction and molecular studies (deoxyribonucleic acid [DNA] barcoding, based on one gene, the mitochondrial cytochrome c oxidase subunit I). In addition, novel DNA barcodes for a land leech from Madagascar and a recently discovered species from Europe were obtained. Our phylogenetic tree shows that X. lecomtei is not a member of the tropical land leeches (family Haemadipsidae), as previously thought, but represents a separate line of descent (family Xerobdellidae). The decline of the local leech population around Graz correlates with a rise in average summer temperatures of +3°C between 1961 and 2004. This warming led to a drastic reduction in the moisture content of the soil where X. lecomtei lives. We suggest that human-induced climate change without apparent habitat destruction can lead to the extinction of populations of cold-adapted species that have a low colonization ability.

  9. Development of Low Global Warming Potential Refrigerant Solutions for Commercial Refrigeration Systems using a Life Cycle Climate Performance Design Tool

    SciTech Connect

    Abdelaziz, Omar [ORNL] [ORNL; Fricke, Brian A [ORNL] [ORNL; Vineyard, Edward Allan [ORNL] [ORNL

    2012-01-01

    Commercial refrigeration systems are known to be prone to high leak rates and to consume large amounts of electricity. As such, direct emissions related to refrigerant leakage and indirect emissions resulting from primary energy consumption contribute greatly to their Life Cycle Climate Performance (LCCP). In this paper, an LCCP design tool is used to evaluate the performance of a typical commercial refrigeration system with alternative refrigerants and minor system modifications to provide lower Global Warming Potential (GWP) refrigerant solutions with improved LCCP compared to baseline systems. The LCCP design tool accounts for system performance, ambient temperature, and system load; system performance is evaluated using a validated vapor compression system simulation tool while ambient temperature and system load are devised from a widely used building energy modeling tool (EnergyPlus). The LCCP design tool also accounts for the change in hourly electricity emission rate to yield an accurate prediction of indirect emissions. The analysis shows that conventional commercial refrigeration system life cycle emissions are largely due to direct emissions associated with refrigerant leaks and that system efficiency plays a smaller role in the LCCP. However, as a transition occurs to low GWP refrigerants, the indirect emissions become more relevant. Low GWP refrigerants may not be suitable for drop-in replacements in conventional commercial refrigeration systems; however some mixtures may be introduced as transitional drop-in replacements. These transitional refrigerants have a significantly lower GWP than baseline refrigerants and as such, improved LCCP. The paper concludes with a brief discussion on the tradeoffs between refrigerant GWP, efficiency and capacity.

  10. Efficacy of body ventilation system for reducing strain in warm and hot climates.

    PubMed

    Chinevere, Troy D; Cadarette, Bruce S; Goodman, Daniel A; Ely, Brett R; Cheuvront, Samuel N; Sawka, Michael N

    2008-06-01

    This study determined whether a torso-vest forced ambient air body ventilation system (BVS) reduced physiological strain during exercise-heat stress. Seven heat-acclimated volunteers attempted nine, 2-h treadmill walks at 200 W m(-2) in three environments, -40 degrees C, 20% rh (HD), 35 degrees C, 75% rh (HW), and 30 degrees C, 50% rh, (WW) wearing the Army Combat Uniform, interceptor body armor (IBA) and Kevlar helmet. Three trials in each environment were BVS turned on (BVS(On)), BVS turned off (BVS(Off)), and no BVS (IBA). In HD, BVS(On) significantly lowered core temperature (T (re)), heart rate (HR), mean skin temperature (T (sk)), mean torso skin temperature (T (torso)), thermal sensation (TS), heat storage (S), and physiological strain index (PSI), versus BVS(Off) and IBA (P < 0.05). For HW (n = 6), analyses were possible only through 60 min. Exercise tolerance time (min) during HW was significantly longer for BVS(On) (116 +/- 10 min) versus BVS(Off) (95 +/- 22 min) and IBA (96 +/- 18 min) (P < 0.05). During HW, BVS(On) lowered HR at 60 min versus IBA, T (sk) from 30 to 60 min versus BVS(Off) and IBA, and PSI from 45 to 60 min versus BVS(Off) and at 60 min versus IBA (P < 0.05). BVS(On) changes in T (re) and HR were lower in HD and HW. During WW, BVS(On) significantly lowered HR, T (sk), and T (torso) versus BVS(Off) and IBA (P < 0.05) during late exercise. Sweating rates were significantly lower for BVS(On) versus BVS(Off) and IBA in both HD and WW (P < 0.05), but not HW. These results indicate that BVS(On) reduces physiological strain in all three environments by a similar amount; however, in hot-dry conditions the BVS(Off) increases physiological strain. PMID:18327605

  11. Warming shifts `worming': effects of experimental warming on invasive earthworms in northern North America

    NASA Astrophysics Data System (ADS)

    Eisenhauer, Nico; Stefanski, Artur; Fisichelli, Nicholas A.; Rice, Karen; Rich, Roy; Reich, Peter B.

    2014-11-01

    Climate change causes species range shifts and potentially alters biological invasions. The invasion of European earthworm species across northern North America has severe impacts on native ecosystems. Given the long and cold winters in that region that to date supposedly have slowed earthworm invasion, future warming is hypothesized to accelerate earthworm invasions into yet non-invaded regions. Alternatively, warming-induced reductions in soil water content (SWC) can also decrease earthworm performance. We tested these hypotheses in a field warming experiment at two sites in Minnesota, USA by sampling earthworms in closed and open canopy in three temperature treatments in 2010 and 2012. Structural equation modeling revealed that detrimental warming effects on earthworm densities and biomass could indeed be partly explained by warming-induced reductions in SWC. The direction of warming effects depended on the current average SWC: warming had neutral to positive effects at high SWC, whereas the opposite was true at low SWC. Our results suggest that warming limits the invasion of earthworms in northern North America by causing less favorable soil abiotic conditions, unless warming is accompanied by increased and temporally even distributions of rainfall sufficient to offset greater water losses from higher evapotranspiration.

  12. Early Mars Climate Models

    Microsoft Academic Search

    Robert M. Haberle

    1998-01-01

    It is often stated that Mars and Earth had similar environmental conditions early in their history and that life might therefore have originated on Mars as well as on Earth. However, the atmospheric conditions required to produce and sustain a warm, wet climate on early Mars remain uncertain. State-of-the-art greenhouse models predict global mean surface temperatures early in Mars' history

  13. Food Security Under Shifting Economic, Demographic, and Climatic Conditions (Invited)

    NASA Astrophysics Data System (ADS)

    Naylor, R. L.

    2013-12-01

    Global demand for food, feed, and fuel will continue to rise in a more populous and affluent world. Meeting this demand in the future will become increasingly challenging with global climate change; when production shocks stemming from climate variability are added to the new mean climate state, food markets could become more volatile. This talk will focus on the interacting market effects of demand and supply for major food commodities, with an eye on climate-related supply trends and shocks. Lessons from historical patterns of climate variability (e.g., ENSO and its global teleconnections) will be used to infer potential food security outcomes in the event of abrupt changes in the mean climate state. Domestic food and trade policy responses to crop output and price volatility in key producing and consuming nations, such as export bans and import tariffs, will be discussed as a potentially major destabilizing force, underscoring the important influence of uncertainty in achieving--or failing to achieve--food security.

  14. Potential Effects of a Warming Climate on Water Resources within the Lehman and Baker Creek Drainages, Great Basin National Park, Nevada

    NASA Astrophysics Data System (ADS)

    Volk, John M.

    Warming trends in near-surface air temperature across the Southwestern U.S. have been observed over the last century and are projected to continue over the 21st century. This warming trend will result in decreased snowpack and earlier snowmelt in mountainous basins throughout the West; however, predictions of future precipitation in the Southwest are much more uncertain among global climate models (GCMs). In this study, the objective was to quantitatively evaluate the impacts of projected warming on streamflow in the Lehman and Baker Creek drainages. The drainages are located in Great Basin National Park that encompasses the highest elevations in the southern part of the Snake Range in eastern Nevada. The Precipitation-Runoff Modeling System (PRMS) was used to evaluate impacts of warming on streamflow. Calibration and validation periods had total errors between 0.6 and 12 percent in simulated streamflow. Daily maximum and minimum temperatures for a future 90-year period were used in the model to evaluate how warming temperatures may affect streamflow. Daily temperatures were statistically downscaled and bias corrected using daily projections from the National Center for Atmospheric Research Community Climate System Model 4.0 for four representative greenhouse gas concentration trajectories. A 30-year record of historical precipitation was repeated three times over the 90-year simulation. Results from the 90-year simulation were divided into three 30-year periods (water years 2009--2038, 2039--2068, and 2069--2098) and were compared among the four greenhouse gas concentration trajectories such that volumes and variations in precipitation were identical and changes could be directly related to different projected warming temperatures. The study area was sensitive to small increases in temperature; results include shifts to earlier snowmelt timing for most warming trajectories from May to April with an increase in winter streamflow. For a temperature rise of 5.5°F by the end of the century, mean annual streamflow was reduced more than 10 percent and resulted in a corresponding increase in evapotranspiration; also a significant decrease in peak snowpack and May runoff was simulated. Reduced snowpack and earlier snowmelt affected the snow-dominated watersheds by reducing soil moisture and evapotranspiration in July and August.

  15. Decreased structural defence of an invasive thistle under warming.

    PubMed

    Zhang, R; Leshak, A; Shea, K

    2012-01-01

    Plant structural defences play a key role in preventing fitness loss due to herbivory. However, how structural defences are affected by potential climate change is rarely examined. We examined how leaf morphological traits that relate to the structural defence of an invasive thistle, Carduus nutans, change in a warmer climate. We manipulated warming using open-top chambers (OTCs) and examined the morphology of leaves at three different positions (the 5th, 10th and 15th leaves, counted from the top of the plant) in two destructive summer censuses. We found that structural defence traits were different under ambient versus warmed conditions. Prickle densities (both the number of prickles per leaf area and the number of prickles per leaf mass) were significantly lower in plants grown in a warmer climate. Our results suggest that plant structural defences may be reduced under warming, and therefore should be considered when examining species' responses to climate change. PMID:21973078

  16. Maternal warming affects early life stages of an invasive thistle.

    PubMed

    Zhang, R; Gallagher, R S; Shea, K

    2012-03-01

    Maternal environment can influence plant offspring performance. Understanding maternal environmental effects will help to bridge a key gap in the knowledge of plant life cycles, and provide important insights for species' responses under climate change. Here we show that maternal warming significantly affected the early life stages of an invasive thistle, Carduus nutans. Seeds produced by plants grown in warmed conditions had higher germination percentages and shorter mean germination times than those produced by plants under ambient conditions; this difference was most evident at suboptimal germination temperatures. Subsequent seedling emergence was also faster with maternal warming, with no cost to seedling emergence percentage and seedling growth. Our results suggest that maternal warming may accelerate the life cycle of this species via enhanced early life-history stages. These maternal effects on offspring performance, together with the positive responses of the maternal generation, may exacerbate invasions of this species under climate change. PMID:22404764

  17. USING ADAPTATION STRATEGIES TO INCREASE WATER USE EFFICIENCY FOR MAIZE UNDER CLIMATE CHANGE CONDITIONS

    Microsoft Academic Search

    Samiha A. Ouda; Fouad A. Khalil; Hassan Yousef

    2009-01-01

    The impact of climate change on water use efficiency under climate change conditions and under using three adaptation strategies was tested for two maize hybrids (TWC310 and TWC324) planted in two growing seasons (2007 and 2008) at Giza, Egypt using CropSyst model with two climate change scenarios. These scenarios were A2 (temperature increase by 3.1°C and CO2 concentration is 834

  18. Effect of dietary ascorbic acid on the performance of laying hens under warm environmental conditions

    Microsoft Academic Search

    Ishak T. Kechik; A. H. Sykes

    1974-01-01

    Two trials were conducted to investigate the effects of dietary ascorbic acid (AA) on the performance of laying hens maintained under high environmental temperatures (32.2 °C and 33.3 °C, respectively), and a third trial was carried out under ambient conditions (12.8 °C to 17.3 °C).Weekly changes in egg yield, shell deformation, percentage of cracked eggs and body weight showed an

  19. Forming characteristics of austenitic stainless steel sheet alloys under warm hydroforming conditions

    Microsoft Academic Search

    Muammer Koç; Sasawat Mahabunphachai; Eren Billur

    2011-01-01

    Stainless steel sheet alloys have been increasingly used in heating, ventilating, and air conditioning; appliance; sanitary\\u000a and medical devices; as well as several structural and transportation applications, due to their high strength-to-weight ratio,\\u000a corrosion resistance, biomedical compatibility, and esthetic appearance. Among various stainless steel alloys, austenitic\\u000a stainless steels are the most commonly used type. Due to the forming limitations into

  20. Validation of lateral boundary conditions for regional climate models

    NASA Astrophysics Data System (ADS)

    Pignotti, Angela J.

    California boasts a population of more than 34 million and is the tenth largest energy consumer in the world. As such, the California Energy Commission (CEC) is greatly concerned about the environmental impacts of global climate change on energy needs, production and distribution. In order to better understand future energy needs in California, the CEC depends upon international climate scientists who use results from simulations of western U.S. regional climate models (RCMs). High-resolution RCMs are driven by coupled Atmosphere/Ocean General Circulation Model (AOGCM) simulations along lateral surface boundaries outlining the region of interest. For projections of future climate, however, when the RCM is driven by future climate change output from an AOGCM, the performance of an RCM will depend to some degree on the merit of the AOGCM. The objective of this study is to provide tools to assist with model validation of coupled Atmosphere/Ocean General Circulation Model (AOGCM) simulations against present-day observations. A comparison technique frequently utilized by climate scientists is multiple hypothesis testing, which identifies statistically significant regions of difference between spatial fields. In order to use these methods, the AOGCM fields must be interpolated onto the reanalysis grid. In this work, I present an efficient interpolation technique using thin-plate splines. I then compare significant regions of difference using multiple testing procedures of Bonferoni against the false detection rate methodology. A major drawback of multiple hypothesis methods is that they do not account for correlation in the spatial field. I introduce and employ measures of comparison, including the Mahalanobis distance measure, that account for anisotropy within the spatial field. Bayesian techniques are applied to calculate comparison measures between the driver-GCM lateral surface boundaries and the NCEP/NCAR and ERA40 reanalysis data sets. I find that the Mahalanobis measure provides a systematic ranking of model performance against present-day observations.

  1. The Great Warming Brian Fagan

    NASA Astrophysics Data System (ADS)

    Fagan, B. M.

    2010-12-01

    The Great Warming is a journey back to the world of a thousand years ago, to the Medieval Warm Period. Five centuries of irregular warming from 800 to 1250 had beneficial effects in Europe and the North Atlantic, but brought prolonged droughts to much of the Americas and lands affected by the South Asian monsoon. The book describes these impacts of warming on medieval European societies, as well as the Norse and the Inuit of the far north, then analyzes the impact of harsh, lengthy droughts on hunting societies in western North America and the Ancestral Pueblo farmers of Chaco Canyon, New Mexico. These peoples reacted to drought by relocating entire communities. The Maya civilization was much more vulnerable that small-scale hunter-gatherer societies and subsistence farmers in North America. Maya rulers created huge water storage facilities, but their civilization partially collapsed under the stress of repeated multiyear droughts, while the Chimu lords of coastal Peru adapted with sophisticated irrigation works. The climatic villain was prolonged, cool La Niñalike conditions in the Pacific, which caused droughts from Venezuela to East Asia, and as far west as East Africa. The Great Warming argues that the warm centuries brought savage drought to much of humanity, from China to Peru. It also argues that drought is one of the most dangerous elements in today’s humanly created global warming, often ignored by preoccupied commentators, but with the potential to cause over a billion people to starve. Finally, I use the book to discuss the issues and problems of communicating multidisciplinary science to the general public.

  2. The study of climate suitability for grapevine cropping using ecoclimatic indicators under climatic change conditions in France

    NASA Astrophysics Data System (ADS)

    Garcia de Cortazar-Atauri, I.; Caubel, J.; Cufi, J.; Huard, F.; Launay, M.; deNoblet, N.

    2013-12-01

    Climatic conditions play a fundamental role in the suitability of geographical areas for cropping. In the case of grape, climatic conditions such as water supply and temperatures have an effect of grape quality. In the context of climate change, we could expect changes in overall climatic conditions and so, in grape quality. We proposed to use GETARI (Generic Evaluation Tool of Ecoclimatic Indicators) in order to assess the future climate suitability of two French sites for grape (Vitis vinifera) regarding its quality. GETARI calculates an overall climate suitability index at the annual scale, from a designed evaluation tree. This aggregation tool proposes the major ecophysiological processes taking place during phenological periods, together with the climatic effects that are known to affect their achievement. The effects of climate on the ecophysiological processes are captured by the ecoclimatic indicators, which are agroclimatic indicators calculated over phenological periods. They give information about crop response to climate through ecophysiological or agronomic thresholds. These indicators are normalized and aggregated according to aggregation rules in order to compute an overall climate index. To assess the future climate suitability of two French sites for grape regarding its quality, we designed an evaluation tree from GETARI, by considering the effect of water deficit between flowering and veraison and the effect of water deficit, water excess, heat stress, temperature ranges between day and night, night temperatures and mean temperatures between veraison and harvest. The two sites are located in Burgundy and Rhone valley which are two of the most important vineyards in the world. Ecoclimatic indicators are calculated using phenological cycle of the crop. For this reason we chose Grenache and Pinot Noir as long and short cycle varieties respectively. Flowering, veraison and harvest dates were simulated (Parker et al., 2011; Yiou et al., 2012). Daily climatic data from 1950 to 2100 were simulated by the global climate model ARPEGE forced by a greenhouse effect corresponding to the SRES A1B scenario were used (data from CERFACS SCRATCH08 - http://www.drias-climat.fr), using the quantile-quantile downscaling method. The results provide information about the climate suitability for grapevine quality in the future and can be used for anticipating and adapting viticulture. This work is carried out under the research program ORACLE (Opportunities and Risks of Agrosystems & forests in response to CLimate, socio-economic and policy changEs in France (and Europe). Parker, A. K., de Cortazar-Atauri, I. G., van Leeuwen, C., Chuine, I., 2011. General phenological model to characterise the timing of flowering and veraison of Vitis vinifera L. Australian Journal of Grape and Wine Research. 17, 206-216. Yiou, P., de Cortazar-Atauri, I. G., Chuine, I., Daux, V., Garnier, E., Viovy, N., van Leeuwen, C., Parker, A. K., Boursiquot, J. M., 2012. Continental atmospheric circulation over Europe during the Little Ice Age inferred from grape harvest dates. Climate of the Past. 8, 577-588.

  3. A surprise result of geothermal numerical simulation - Persistent drawdown of ground water table may reduce local climate warming rate

    NASA Astrophysics Data System (ADS)

    Yin, Fengling; Shi, Yaolin; Zhang, Huai

    2014-05-01

    Due to persistent groundwater over-exploitation since the 1970s, groundwater level has been found significantly declined in a large area of more than 70,000 km2 in Beijing, Tianjing and Hebei Provinces in North China. Consequently, a series of geo-environmental problems have emerged and drawn widely public attentions, such as land subsidence, groundwater contamination, sea water invasion, etc. We found that decline of water table can result in significant reduction in geothermal heat flux density, and this effect has never been discussed in literatures. Thermal properties, such as thermal conductivity, specific heat, are different for layers of water saturated sediment beneath the water table and layers of dry sediments above the water table. When the water table declines, due to the variation of thermal properties, transcend changes of underground geotherm occurs. Our numerical simulation indicates that surface heat flow density may reduce 40%, about 25mW/m2 in ground water drawdown zone in North China after more than 40 years over-exploitation, and the surface heat flow density cannot return to normal state for hundreds of years even if the water table does not decline any more from now on. The amount of reduction of heat flow density is small, but it can last for long period of hundreds of years, and cover a large area of 70,000 km2, its effect on climate may not be negligible. It is estimated that this reduction of surface heat flow may reduce an air column temperature 0.08°/a if it is adiabatic with surroundings, while the actual air temperature warming rate is only 0.03°/a in the depress zone and 0.05C/a outside the depression zone in North China. Meteorological subsurface temperature (up to 3.2m depth) records show similar trend. Although air temperatures are influenced by many factors, but the decline of surface heat flow density should be one of the factors to be studied. We suggest that more attention should be paid to this effect, and systematic monitoring of geotherm at tens to hundred meters depth should be carried out.

  4. Innovative HVAC Cycles for Severe Part Load Conditions in the Humid Climate

    E-print Network

    Pate, M. E.; Todd, T. R.

    1987-01-01

    , Arlington, Texas, 1986. 3. Todd, T., Pate, M., "Passive Humidity Control: A Comparison of Air Conditioning Capaci- ty Control Methods for the Humid Climate ,I1 ASHRAE Far East Conference, Singapore, September, 1987. 4. Meckler, Gershon, "Energy-Integra...

  5. Experimental investigation of two-stage indirect\\/direct evaporative cooling system in various climatic conditions

    Microsoft Academic Search

    Ghassem Heidarinejad; Mojtaba Bozorgmehr; Shahram Delfani; Jafar Esmaeelian

    2009-01-01

    Cooling performance of two-stage indirect\\/direct evaporative cooling system is experimentally investigated in the various simulated climatic conditions. For this purpose, a two-stage evaporative cooling experimental setup consisting of an indirect evaporative cooling stage (IEC) followed by a direct evaporative cooling stage (DEC) was designed, constructed and tested. Due to the wide variety of climatic conditions in Iran, two air simulators

  6. Collaborative Research for Water Resource Management under Climate Change Conditions

    NASA Astrophysics Data System (ADS)

    Brundiers, K.; Garfin, G. M.; Gober, P.; Basile, G.; Bark, R. H.

    2010-12-01

    We present an ongoing project to co-produce science and policy called Collaborative Planning for Climate Change: An Integrated Approach to Water-Planning, Climate Downscaling, and Robust Decision-Making. The project responds to motivations related to dealing with sustainability challenges in research and practice: (a) state and municipal water managers seek research that addresses their planning needs; (b) the scientific literature and funding agencies call for more meaningful engagement between science and policy communities, in ways that address user needs, while advancing basic research; and (c) empirical research contributes to methods for the design and implementation of collaborative projects. To understand how climate change might impact water resources and management in the Southwest US, our project convenes local, state, and federal water management practitioners with climate-, hydrology-, policy-, and decision scientists. Three areas of research inform this collaboration: (a) the role of paleo-hydrology in water resources scenario construction; (b) the types of uncertainties that impact decision-making beyond climate and modeling uncertainty; and (c) basin-scale statistical and dynamical downscaling of climate models to generate hydrologic projections for regional water resources planning. The project engages all participants in the research process, from research design to workshops that build capacity for understanding data generation and sources of uncertainty to the discussion of water management decision contexts. A team of “science-practice translators” facilitates the collaboration between academic and professional communities. In this presentation we contextualize the challenges and opportunities of use-inspired science-policy research collaborations by contrasting the initial project design with the process of implementation. We draw from two sources to derive lessons learned: literature on collaborative research, and evaluations provided by participating scientists and water managers throughout the process. Lessons learned include: RESULTS: The research process needs to generate academic (peer-reviewed publications, grant proposals) and applied (usable dataset, communication support) products. Additionally, the project also strives for intangible products, e.g., the research currently continues to support efforts to predict future regional hydroclimatology, whereas management requires a paradigm shift toward anticipation of needs for adapting to multiple possible futures. APPROACH: Collaborative research is not a one-off event or consultation, but a process of mutual engagement that needs to allow for adaptive evolution of the project and its organization. TOPICS: With the acceptance of hydroclimatic non-stationarity, the focus of water managers shifts from reducing scientific uncertainty to enhancing their ability to present academically and politically defensible scenarios to their constituencies. This requires addressing the related need for exploring how to deal with political and institutional uncertainties in decision-making.

  7. A review of Tertiary climate changes in southern South America and the Antarctic Peninsula. Part 1: Oceanic conditions

    NASA Astrophysics Data System (ADS)

    Le Roux, J. P.

    2012-03-01

    Oceanic conditions around southern South America and the Antarctic Peninsula have a major influence on climate patterns in these subcontinents. During the Tertiary, changes in ocean water temperatures and currents also strongly affected the continental climates and seem to have been controlled in turn by global tectonic events and sea-level changes. During periods of accelerated sea-floor spreading, an increase in the mid-ocean ridge volumes and the outpouring of basaltic lavas caused a rise in sea-level and mean ocean temperature, accompanied by the large-scale release of CO2. The precursor of the South Equatorial Current would have crossed the East Pacific Rise twice before reaching the coast of southern South America, thus heating up considerably during periods of ridge activity. The absence of the Antarctic Circumpolar Current before the opening of the Drake Passage suggests that the current flowing north along the present western seaboard of southern South American could have been temperate even during periods of ridge inactivity, which might explain the generally warm temperatures recorded in the Southeast Pacific from the early Oligocene to middle Miocene. Along the east coast of southern South America, water temperatures also fluctuated between temperate-cool and warm until the early Miocene, when the first incursion of temperate-cold to cold Antarctic waters is recorded. The cold Falkland/Malvinas Current initiated only after the middle Miocene. After the opening of the Drake Passage, the South Equatorial Current would have joined the newly developed, cold Antarctic Circumpolar Current on its way to Southern South America. During periods of increased sea-floor spreading, it w