Abstracts on Global Climate Change

Mar 2006

Marine lake ecosystem dynamics illustrate ENSO variation in the tropical western Pacific

Martin, LE Dawson, MN Bell, LJ Colin, PL


Understanding El Nino/Southern Oscillation (ENSO) and its biological consequences is hindered by a lack of high-resolution, long-term data from the tropical western Pacific. We describe a preliminary, 6 year dataset that shows tightly coupled ENSO-related bio-physical dynamics in a seawater lake in Palau, Micronesia. The lake is more strongly stratified during La Nina than El Nino conditions, temperature anomalies in the lake co-vary strongly with the Nino 3.4 climate index, and the abundance of the dominant member of the pelagic community, an endemic subspecies of zooxanthellate jellyfish, is temperature associated. These results have broad relevance because the lake: (i) illustrates an ENSO signal that is partly obscured in surrounding semi-enclosed lagoon waters and, therefore, (ii) may provide a model system for studying the effects of climate change on community evolution and cnidarian-zooxanthellae symbioses, which (iii) should be traceable throughout the Holocene because the lake harbours a high quality sediment record; the sediment record should (iv) provide a sensitive and regionally unique record of Holocene climate relevant to predicting ENSO responses to future global climate change and, finally, (v) seawater lake ecosystems elsewhere in the Pacific may hold similar potential for past, present, and predictive measurements of climate variation and ecosystem response.

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Can the invaded range of a species be predicted sufficiently using only native-range data? Lehmann lovegrass (Eragrostis lehmanniana) in the southwestern United States

Mau-Crimmins, TM Schussman, HR Geiger, EL


Predictions of species invasions are often made using information from their native ranges. Acquisition of native-range information can be very costly and time-consuming and in some cases may not reflect conditions in the invaded range. Using information from the invaded range can enable much faster modeling at finer geographic resolutions than using information from a species’ native range. We used confirmed presence points from the native range, southern Africa, and the invaded range, the southwestern United States, to predict the potential distribution of the perennial bunchgrass Eragrostis lehmanniana Nees, (Lehmann lovegrass), in its invaded range in the United States. The two models showed strong agreement for the area encompassed by the presence points in the invaded range, and offered insight into the overlapping but slightly different ecological niche occupied by the introduced grass in the invaded range. Regions outside of the scope of inference showed less agreement between the two models. E. lehmanniana was selected via seeding trials before being planted in the United States and therefore represents an isolated genotype from the native-range population. Models built using confirmed presence points from the invaded range can provide insight into how the selected genotype is expressed on the landscape and considers influences not present in the native range. Models created from locations in both the invaded and native ranges can lead to a more complete understanding of an introduced species’ potential for spread, especially in the case of anthropogenic selection. (C) 2005 Elsevier B.V. All rights reserved.

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Paleomonsoon precipitation deduced from a sediment core from the equatorial Indian Ocean

Tiwari, M Ramesh, R Somayajulu, BLK Jull, AJT Burr, GS


Rapid shifts in past climate recorded in polar ice sheets have elicited various explanations relating to either thermohaline circulation changes by ice-rafting or natural greenhouse gas concentrations modulated by climatic conditions in the tropics. To compare the tropical paleoclimate record with the polar record, one must choose sediment cores from highly productive ocean regions. Necessarily, such regions reflect the wind records in the tropics, because high productivity is associated with upwelling driven by winds. Comparing tropical precipitation records with high-latitude records is, however, a more difficult task because sediments recording paleoprecipitation usually have low sedimentation rates, and offer coarser resolution relative to polar ice cores. Here, we present delta O-18 data of three planktonic species of Foraminifera (a proxy for precipitation) from such a sediment core, spanning the past 35 ka for the equatorial Indian Ocean, which falls under the southwest monsoon (SWM) realm. Results show that minimum SWM precipitation occurred at the Last Glacial Maximum, with a subsequent increase at Termination IA. During the Holocene, SWM precipitation intensified uniformly up to the core top (similar to 2.2 ka B.P.), as revealed by generally decreasing delta O-18 values. Variations in precipitation are consistent with climate changes recorded in polar ice sheets. Although the different resolutions of the two records preclude a rigorous comparison, abrupt cooling/warming events appear to be accompanied by sudden reduction/enhancement in (SWM) rainfall. Thus, mechanisms with time scales much shorter than a millennium, such as natural greenhouse warming (e.g., CH4 concentration), controlled by emissions from the tropics, could have played a major role in high-latitude climate change.

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The (OECTS)-E-bj framework for integrated assessment: Hybrid modeling of transportation

Kim, SH Edmonds, J Lurz, J Smith, SJ Wise, M


Technology is a central issue for the global climate change problem, requiring analysis tools that can examine the impact of specific technologies within a long-term, global context. This paper describes the architecture of the ObjECTS-MiniCAM integrated assessment model, which implements a long-term, global model of energy, economy, agriculture, land-use, atmosphere, and climate change in a framework that allows the flexible incorporation of explicit technology detail. We describe the implementation of a “bottom-up” representation of the transportation sector as an illustration of this approach, in which the resulting hybrid model is fully integrated, internally consistent and theoretically compatible with the regional and global modeling framework. The analysis of the transportation sector presented here supports and clarifies the need for a comprehensive strategy promoting advanced vehicle technologies and. an economy-wide carbon policy to cost-effectively reduce carbon emissions from the transportation sector in the long-term.

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Phenotypic diversity amongst strains of Pleurotus sajor-caju: implications for cultivation in and environments

Kashangura, C Hallsworth, JE Mswaka, AY


In and regions, biodiversity and biomass are limited by water availability, and this problem has been compounded by desertification associated with global climate change. The saprotrophic macrofungi that are indigenous to hot subtropical and tropical regions, such as Pleurotus spp., can play key roles in water sequestration, nutrient cycling, human nutrition, and bioremediation of waste materials. We studied 15 strains of Pleurotus sajor-caju, a widespread and phenotypically-diverse species, to establish variability in growth response and primordium development over a range of stress parameters: osmotic potential (-0.5 to -5 MPa), temperature (5-40 degrees C) and pH (2-12). The initiation of primordia precedes basidiome production and therefore represents a key stage in bioremediation strategies and fungi-driven nutrient cycles. Primordia. were produced at low pH (4-6), at suboptimal growth temperatures (<= 25 degrees C), and under moderate water stress (-0.5 to -3.5 MPa). Although the growth windows for different strains were similar, their maximum growth rates and the optimum conditions for growth varied. We discuss the phenotypic diversity of Pleurotus strains and discuss their potential for cultivation, bioremediation and ecological regeneration. (c) 2005 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

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Root exudation (net efflux of amino acids) may increase rhizodeposition under elevated CO2

Philips, DA Fox, TC Six, J


Increases in atmospheric CO2 concentration ([CO2]) can lead to global climate change and theoretically could enhance carbon (C) deposition in soil, but data on this complex issue are contradictory. One approach for clarifying the diverse forces influencing plant-derived C in the rhizosphere involves defining how elevated [CO2] alters the fundamental process of C transfer from plant roots to the soil. We examine here how a step increase in [CO2] affects the innate influx and efflux components of root exudation in axenic plants, as one foundation for understanding how climate change may affect rhizodeposition. Increasing [CO2] from 425 to 850 mu mol mol(-1) during short-term trials enhanced shoot and root dry weight (P < 0.01) of annual rye grass (Lolium multiflorum Lam.) and medic (Medicago truncatula L.) but had no effect on growth of maize (Zea mays L.). Root amino-acid flux in the same plants changed only in maize, which increased the efflux rate (nmol g root fresh weight(-1) h(-1)) of six amino acids (arginine, alanine, proline, tyrosine, lysine and leucine) significantly (P < 0.05) under elevated [CO2]. None of the three plant species altered the steady-state concentration of 16 amino acids released into a hydroponic solution with changing [CO2], apparently because amino-acid influx rates, measured at 2.5 mu M, consistently exceeded efflux rates. Indeed, plants recovered amino acids at rates 94-374% higher than they were lost from roots regardless of [CO2]. These results indicate that, in theory, any effect of [CO2] doubling on amino-acid efflux can be offset by innately higher rates of influx. In practice, however, higher rates of amino-acid cycling (i.e., efflux+influx) for each root segment (in C-4 maize) or from more root tissue (in the two C-3 species) should increase root exudation by plants exposed to elevated [CO2] as additional amino acids would be adsorbed to soil particles or be taken up by soil microorganisms.

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GFDL’s CM2 global coupled climate models. Part I: Formulation and simulation characteristics

Delworth, TL Broccoli, AJ Rosati, A Stouffer, RJ Balaji, V Beesley, JA Cooke, WF Dixon, KW Dunne, J Dunne, KA Durachta, JW Findell, KL Ginoux, P Gnanadesikan, A Gordon, CT Griffies, SM Gudgel, R Harrison, MJ Held, IM Hemler, RS Horowitz, LW Klein, SA Knutson, TR Kushner, PJ Langenhorst, AR Lee, HC Lin, SJ Lu, J Malyshev, SL Milly, PCD Ramaswamy, V Russell, J Schwarzkopf, MD Shevliakova, E Sirutis, JJ Spelman, MJ Stern, WF Winton, M Wittenberg, AT Wyman, B Zeng, F Zhang, R


The formulation and simulation characteristics of two new global coupled climate models developed at NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL) are described. The models were designed to simulate atmospheric and oceanic climate and variability from the diurnal time scale through multicentury climate change, given our computational constraints. In particular, an important goal was to use the same model for both experimental seasonal to interannual forecasting and the study of multicentury global climate change, and this goal has been achieved. Two versions of the coupled model are described, called CM2.0 and CM2.1. The versions differ primarily in the dynamical core used in the atmospheric component, along with the cloud tuning and some details of the land and ocean components. For both coupled models, the resolution of the land and atmospheric components is 2 degrees latitude x 2.5 degrees longitude, the atmospheric model has 24 vertical levels. The ocean resolution is 1 degrees in latitude and longitude, with meridional resolution equatorward of 30 degrees becoming progressively finer, such that the meridional resolution is 1/3 degrees at the equator. There are 50 vertical levels in the ocean, with 22 evenly spaced levels within the top 220 m. The ocean component has poles over North America and Eurasia to avoid polar filtering. Neither coupled model employs flux adjustments. The control simulations have stable, realistic climates when integrated over multiple centuries. Both models have simulations of ENSO that are substantially improved relative to previous GFDL coupled models. The CM2.0 model has been further evaluated as an ENSO forecast model and has good skill (CM2.1 has not been evaluated as an ENSO forecast model). Generally reduced temperature and salinity biases exist in CM2.1 relative to CM2.0. These reductions are associated with 1) improved simulations of surface wind stress in CM2.1 and associated changes in oceanic gyre circulations; 2) changes in cloud tuning and the land model, both of which act to increase the net surface shortwave radiation in CM2.1, thereby reducing an overall cold bias present in CM2.0; and 3) a reduction of ocean lateral viscosity in the extratropics in CM2.1, which reduces sea ice biases in the North Atlantic. Both models have been used to conduct a suite of climate change simulations for the 2007 Intergovernmental Panel on Climate Change (IPCC) assessment report and are able to simulate the main features of the observed warming of the twentieth century. The climate sensitivities of the CM2.0 and CM2.1. models are 2.9 and 3.4 K, respectively. These sensitivities are defined by coupling the atmospheric components of CM2.0 and CM2.1 to a slab ocean model and allowing the model to come into equilibrium with a doubling of atmospheric CO2. The output from a suite of integrations conducted with these models is freely available online (see http://nomads.gfdl.noaa.gov/).

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Climate change and the future of shipping and ship design

Breslin, DA


In 2001, the Intergovernmental Panel on Climate Change (IPCC) issued a series of alarming reports that outlined the likely consequences of climate change over the next 50 to 100 years. Subsequent to those reports, in early 2005, the Kyoto Protocol took effect, establishing modest targets for reducing emissions of global-warming gases by certain countries. Those targets are widely considered to be inadequate to do the job. >> In 2007, the IPCC will issue its next series of reports, and it is widely anticipated that those reports will paint a grim picture of the future, possibly setting off another round of calls to action and negotiations for tougher treaty requirements.))Whatever the immediate reaction to the 2007 IPCC reports, determined action by developed and developing nations alike appears inevitable. That determined action will affect every economic sector, including the shipping and shipbuilding industries. >> So it’s coming time for the leaders, owners, operators, technologists, designers, and manufacturers in the U.S. domestic shipping and shipbuilding industries to begin contemplating what actions they will take to address possible legal requirements associated with global climate change. >> Previous papers on climate change by this author have focused on ship technologies (Breslin & Wang, 2004) as well as DoN acquisition strategies (Breslin, 2003). The purpose of this paper is to outline where we are and where we are likely to be going relative to treaties and domestic legislation associated with climate change, speculate on the likely implications relative to shipping and shipbuilding, and outline a rough path into the future.

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Temperature-dependent effects of cadmium on mitochondrial and whole-organism bioenergetics of oysters (Crassostrea virginica)

Lannig, G Cherkasov, AS Sokolova, IM


Intertidal mollusks are exposed to multiple stressors in estuaries, including temperature and trace metals such as cadmium, which may interactively affect their physiology. We have studied the combined effects of temperature and cadmium stress on metabolism of oysters at the whole animal and mitochondrial levels. In vivo exposure to 50 mu g L-1 Cd led to a significant increase in basal metabolic rate (BMR) in 20 degrees C-acclimated but not in 28 degrees C-acclimated oysters. Cadmium exposure resulted in a fast decrease in mitochondrial capacity to synthesize ATP in 28 degrees C-acclimated but not 20 degrees C-acclimated oysters indicating that mitochondria, may be functioning closer to their capacity limits in the former group. This agrees with elevated mortality in Cd-exposed oysters at 28 degrees C but not 20 degrees C. In general, elevated temperature increased sensitivity of oysters to cadmium at mitochondrial and whole-organism levels suggesting that oyster populations may become more susceptible to trace metal pollution during seasonal warming and/or global climate change. (c) 2006 Elsevier Ltd. All rights reserved.

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Dust storm in Asia continent and its bio-environmental effects in the North Pacific: A case study of the strongest dust event in April, 2001 in central Asia

Han, YX Fang, XM Xi, XX Song, LC Yang, SL


Testing the effects of iron fertilization in booming metabolism of microbes in North Pacific Ocean has become an important hot topic in current global climate change study. The first supportive evidence with natural iron inputs to ocean was obtained by Bishop and his colleagues at the PAPA region in North Pacific Ocean. They found a rapid increase of marine phytoplankton over North Pacific Ocean after a strong dust storm in April 2001. We demonstrate that the dust deposition flux during this dust storm period decreases exponentially with increasing distance from the dust source regions along the dust transport pathway, through integration of synoptic dynamics, changes of TOMS-Al (aerosol index) and surface PM10 values along the dust pathway and changes of particulate organic carbon and chlorophyll in surface oceans. This strong dust storm may result in deposition of about 3.1-5.8 mu g/m(3) eolian iron into the PAPA region in North Pacific Ocean, thus causing a rapid increase of marine phytoplankton productivity observed by Bishop and his colleagues. This work supplies more direct and detailed evidence, from continental dust process, to support the iron hypothesis with natural iron inputs to the surface oceans through dust storms.

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Uncertainties of climate change in arid environments of Central Asia

Lioubimtseva, E Cole, R


This article examines the key uncertainties of climate change in the Central Asian republics of the former USSR-a vast arid region arid a classic example of complex and poorly understood interactions between the regional responses to global climate change and the local human-induced desertification. Based on paleoanalogous scenarios, Central Asian deserts are often predicted to become wetter as a result of global warming because they are located north of 30 degrees latitude. However despite some similarities between the paleoclimate changes and greenhouse warming, such predictions have very serious limitations. Climate models predict that the temperature in and Central Asia will increase by 1-2 degrees C by 2030-2050, with the greatest increases in wintertime. Some models project greater aridity in the future though others project less aridity, and it is becoming increasingly apparent that climate change modeling in arid zones is extremely uncertain because of the extreme natural variability (both temporal and spatial) of the desert climate. The physical differences of climate change forcings imply that one might expect quite different regional responses to future human-induced climate change compared to the Holocene climate in terms of their rapidity and amplitude. Local and regional human impacts, such as massive irrigation, may have a stronger impact on the climatic system at the regional level than global climate change.

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Flexible multi-gas climate policies

Jensen, J


I analyse the costs of policies aimed at stabilising global climate change. I show that abatement of all major greenhouse gases is important to the costs of climate policies and that flexible reduction of methane and other non-CO2 gases may reduce costs significantly. The non-CO2 gases offer many low-cost abatement options and this reduces the need for abatement of CO2 to stabilise climate change. Multi-gas flexibility may be important if climate policies reflect not only long-term stabilisation, but also the rate at which the climate changes, as the latter may require large reductions in emissions in the short-term.

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Application of Landsat-7 satellite data and a DEM for the quantification of thermokarst-affected terrain types in the periglacial Lena-Anabar coastal lowland

Grosse, G Schirrmeister, L Malthus, TJ


Extensive parts of Arctic permafrost-dominated lowlands were affected by large-scale permafrost degradation, mainly through Holocene thermokarst activity. The effect of thermokarst is nowadays observed in most periglacial lowlands of the Arctic. Since permafrost degradation is a consequence as well as a significant factor of global climate change, it is necessary to develop efficient methods for the quantification of its past and current magnitude. We developed a procedure for the quantification of periglacial lowland terrain types with a focus on degradation features and applied it to the Cape Mamontov Klyk area in the western Laptev Sea region. Our terrain classification approach was based on a combination of geospatial datasets, including a supervised maximum likelihood classification applied to Landsat-7 ETM+ data and digital elevation data. Thirteen final terrain surface classes were extracted and subsequently characterized in terms of relevance to thermokarst and degradation of ice-rich deposits. 78% of the investigated area was estimated to be affected by permafrost degradation. The overall classification accuracy was 79%. Thermokarst did not develop evenly on the coastal plain, as indicated by the increasingly dense coverage of thermokarst-related areas from south to north. This regionally focused procedure can be extended to other areas to provide the highly detailed periglacial terrain mapping capabilities currently lacking in global-scale permafrost datasets.

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Spatial distribution of rainfall trends in Sicily (1921-2000)

Cannarozzo, M Noto, LV Viola, F


The feared global climate change could have important effects on various environmental variables including rainfall in many countries around the world. Changes in precipitation regime directly affect water resources management, agriculture, hydrology and ecosystems. For this reason it is important to investigate the changes in the spatial and temporal rainfall pattern in order to improve water management strategies. In this study a non-parametric statistical method (Mann-Kendall rank correlation method) is employed in order to verify the existence of trend in annual, seasonal and monthly rainfall and the distribution of the rainfall during the year. This test is applied to about 250 rain gauge stations in Sicily (Italy) after a series of procedures finalized to the estimation of missing records and to the verification of data consistency. In order to understand the regional pattern of precipitation in Sicily, the detected trends are spatially interpolated using spatial analysis techniques in a GIS environment. The results show the existence of a generalized negative trend for the entire region. (c) 2006 Elsevier Ltd. All rights reserved.

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Reducing conflicts between climate policy and energy policy in the US: The important role of the states

Peterson, TD Rose, AZ

ENERGY POLICY 34:5 619-631

The absence of US national action oil global climate change policy has prompted initiatives by the US Congress, cities, states, and regions toward what is likely to become it long-term, collaborative effort to harmonize national energy and climate policies. This upward evolution in the face of it reluctant administration is historically consistent with the development of national legislation on other environmental and social issues in the US. At the heart of this movement is the need to resolve conflicts between high-intensity use of low-cost fossil energy Supplies, and the dominating impact of carbon dioxide emissions oil global climate change. US states are among the largest carbon dioxide emitters in the world and play a critical role in supplying and transforming energy, its well as consuming it, for economic advantage. State governments are also likely to have to shoulder some of the cost of potentially extensive climate damages and bear the brunt of the cost of implementing future federal mandates. As a result, many are taking proactive stances oil the development of climate mitigation policy to prepare for, accelerate, and/or guide national policy. As US states show leadership on addressing greenhouse gas emissions, they also play an important role in forging policies and measures that reduce economic conflict between energy and climate goals. A number have launched or completed greenhouse gas mitigation plans and other major policies in the past few years that address these conflicts through: (1) finding ways to reduce mitigation costs, including the use of incentive-based policy instruments; (2) promoting ail open and democratic policy process that includes major stakeholders; (3) promoting equity across socioeconomic groups, regions, and generations; and (4) promoting interregional cooperation. The results are promising and suggest that the state arena for climate and energy policy is evolving quickly and constructively toward alternatives that reduce conflict. Regional efforts are also unfolding, along with greater congressional attention to the lessons learned and commitments made by sub-federal actions. In the next few years many national energy and climate conflicts are likely to be tested and addressed by states. Among these, Pennsylvania is likely to be an important player due to its high profile of energy production and potential for leadership. (c) 2005 Elsevier Ltd. All rights reserved.

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Soil organic carbon changes in diversified rotations of the western corn belt

Varvel, GE


dSequestration and storage of carbon (C) by agricultural soils has been cited as one potential part of the solution to soil degradation and global climate change. However, C sequestration in soils is a slow and dynamic process. The objective of this study was to evaluate the effects of crop rotation and N fertilizer management on soil organic C (SOC) levels at several points in time during 18 yr of a long-term study in the Western Corn Belt. Seven cropping systems (three monoculture, two 2-yr, and two 4-yr rotations) with three levels of N fertilizer were compared. Soil samples were taken in the spring in 1984, 1992, 1998, and 2002 to a depth of 30 cm in 0- to 7.5-, 7.5- to 15-, and 15- to 30-cm increments. No differences were obtained in SOC levels in 1984 at the beginning of the study. After 8 yr, rotation significantly increased SOC 449 kg ha(-1) across all cropping systems. From 1992 to 2002, SOC levels in the 0- to 7.5-cm depth decreased by 516 kg ha(-1) across all cropping systems. Soil organic C levels in the 7.5- to 15-cm depths in 1992 and 2002 demonstrated similar rotation effects to those in the surface 0- to 7.5-cm, being not significantly affected from 1984 to 1992 but being significantly decreased from 1992 to 2002 (568 kg SOC ha(-1) across all cropping systems). Many of the SOC gains in the surface 30 cm measured during the first 8 yr of the study were lost during the next 10 yr in all but the 4-yr cropping systems after 18 yr. The loss of SOC in this latter period occurred when depth of tillage was increased by using a tandem disk with larger-diameter disks. These results demonstrate that more than one point-in-time measurement from long-term experiments is necessary to monitor SOC changes when several management variables, such as cropping system and N fertilizer, are being used. They also indicate that apparent small changes in cultural practices, such as in depth of tillage in this experiment, can significantly change SOC dynamics in the soil. Subtle changes in cultural practices (e.g., tillage depth) can have significant long-term results, but longterm experiments are required to quantify their impact under variable climatic conditions.

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Global warming: Can existing reserves really preserve current levels of biological diversity?

Li, MH Krauchi, N Gao, SP


Paleoecological evidence and paleoclimatic records indicate that there was a plant poleward migration in latitude and an upward shift in elevation with increased temperatures after the last glaciation. Recent studies have shown that global warming over the past 100 years has been having a noticeable effect on living systems. Current global warming is causing a poleward and upward shift in the range of many plants and animals. Climate change, in connection with other global changes, is threatening the survival of a wide range of plant and animal species. This raises the question: can existing reserves really preserve current levels of biological diversity in the long term given the present rapid pace of climate change? The present paper deals with this question in the context of the responses of plants and animals to global climate change, based on a literature review. Consequently, we recommend expanding reserves towards the poles and/or towards higher altitudes, to permit species to shift their ranges to keep pace with global warming.

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