Abstracts on Global Climate Change

Jan 2006

Rainfall and its seasonality over the Amazon in the 21st century as assessed by the coupled models for the IPCC AR4

Li, WH Fu, R Dickinson, RE


[1] The global climate models for the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) predict very different changes of rainfall over the Amazon under the SRES A1B scenario for global climate change. Five of the eleven models predict an increase of annual rainfall, three models predict a decrease of rainfall, and the other three models predict no significant changes in the Amazon rainfall. We have further examined two models. The UKMO-HadCM3 model predicts an El Nino-like sea surface temperature (SST) change and warming in the northern tropical Atlantic which appear to enhance atmospheric subsidence and consequently reduce clouds over the Amazon. The resultant increase of surface solar absorption causes a stronger surface sensible heat flux and thus reduces relative humidity of the surface air. These changes decrease the rate and length of wet season rainfall and surface latent heat flux. This decreased wet season rainfall leads to drier soil during the subsequent dry season, which in turn can delay the transition from the dry to wet season. GISS-ER predicts a weaker SST warming in the western Pacific and the southern tropical Atlantic which increases moisture transport and hence rainfall in the Amazon. In the southern Amazon and Nordeste where the strongest rainfall increase occurs, the resultant higher soil moisture supports a higher surface latent heat flux during the dry and transition season and leads to an earlier wet season onset.

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Consequences of simultaneous elevation of carbon dioxide and temperature for plant-herbivore interactions: a metaanalysis

Zvereva, EL Kozlov, MV


The effects of elevated carbon dioxide on plant-herbivore interactions have been summarized in a number of narrative reviews and metaanalyses, while accompanying elevation of temperature has not received sufficient attention. The goal of our study is to search, by means of metaanalysis, for a general pattern in responses of herbivores, and plant characteristics important for herbivores, to simultaneous experimental increase of carbon dioxide and temperature (ECET) in comparison with both ambient conditions and responses to elevated CO2 (EC) and temperature (ET) applied separately. Our database includes 42 papers describing studies of 31 plant species and seven herbivore species. Nitrogen concentration and C/N ratio in plants decreased under both EC and ECET treatments, whereas ET had no significant effect. Concentrations of nonstructural carbohydrates and phenolics increased in EC, decreased in ET and did not change in ECET treatments, whereas terpenes did not respond to EC but increased in both ET and ECET; leaf toughness increased in both EC and ECET. Responses of defensive secondary compounds to treatments differed between woody and green tissues as well as between gymnosperm and angiosperm plants. Insect herbivore performance was adversely affected by EC, favoured by ET, and not modified by ECET. Our analysis allowed to distinguish three types of relationships between CO2 and temperature elevation: (1) responses to EC do not depend on temperature (nitrogen, C/N, leaf toughness, phenolics in angiosperm leaves), (2) responses to EC are mitigated by ET (sugars and starch, terpenes in needles of gymnosperms, insect performance) and (3) effects emerge only under ECET (nitrogen in gymnosperms, and phenolics and terpenes in woody tissues). This result indicates that conclusions of CO2 elevation studies cannot be directly extrapolated to a more realistic climate change scenario. The predicted negative effects of CO2 elevation on herbivores are likely to be mitigated by temperature increase.

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Arctic Siberia: refuge of the Mammoth fauna in the Holocene

Boeskorov, GG


Global climate change at the end of Pleistocene led to extinction in the huge territories of Northern Eurasia of the typical representatives of the Mammoth fauna: mammoth, woolly rhinoceros, wild horse, bison, musk-ox, and cave lion. Undoubtedly the Mammoth fauna underwent pressure from Upper Paleolithic humans, whose hunting activity could also have played a role in decreasing the number of mammoths and other representatives of megafauna. Formerly it was supposed that the megafauna of the “Mammoth complex” had become extinct by the beginning of the Holocene. Nevertheless the latest data indicate that extinction of the Mammoth fauna was significantly delayed in the north of Eastern Siberia. In the 1990s some radiocarbon dates established that mammoths existed in the Holocene on Wrangel Island-from 7700 until 3700 yBP. Radiocarbon data show that wild horses inhabited the north of Eastern Siberia 4600-2000 yBP. Muskoxen lived here about 3000 yBP. Some bison remains from Eastern Siberia belong to the Holocene. The following circumstances could promote the survival of representatives of Mammoth fauna. Cool and dry climate in this region promotes the maintenance of steppe associations-the habitats of those mammals. Late Paleolithic and Mesolithic settlements are not found in the Arctic zone of Eastern Siberia from Taimyr Peninsula to the lower Yana River; they are very rare in basins of the Indigirka and Kolyma Rivers. The small number of Stone Age hunting tribes in the northern part of Eastern Siberia was probably another factor that contributed to the survival of some Mammoth fauna representatives. (c) 2005 Published by Elsevier Ltd.

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Tropical Atlantic SST history inferred from Ca isotope thermometry over the last 140ka

Hippler, D Eisenhauer, A Nagler, TF


Exploring the potentials of new methods in palaeothermometry is essential to improve our understanding of past climate change. Here, we present a refinement of the published delta(44/40)Ca-temperature calibration investigating modern specimens of planktonic forarninifera Globigerinoides sacculifer and apply this to sea surface temperature (SST) reconstructions over the last two glacial-interglacial cycles. Reproduced measurements of modern G. sacculifer collected from surface waters describe a linear relationship for the investigated temperature range (19.0-28.5 degrees C): delta(44/40)Ca[parts per thousand] = 0.22 (+/- 0.05)*SST [degrees C] -4.88. Thus a change of delta(44/40) Ca[parts per thousand] of 0.22 (+/- 0.05) corresponds to a relative change of 1 degrees C. The refined delta(44/40) Ca-modern-calibration allows the determination of both relative temperature changes and absolute temperatures in the past. This delta(44/40)Ca(modern)-calibration for G. sacculifer has been applied to the tropical East Atlantic sediment core GeoB1112 for which other SST proxy data are available. Comparison of the different data sets gives no indication for significant secondary overprinting of the delta(44/40)Ca signal. Long-term trends in reconstructed SST correlate strongly with temperature records derived from oxygen isotopes and Mg/Ca ratios supporting the methods validity. The observed change of SST of approximately 3 degrees C at the Holocene-last glacial maximum transition reveals additional evidence for the important role of the tropical Atlantic in triggering global climate change, based on a new independent palaeothermometer. (c) 2005 Elsevier Inc. All rights reserved.

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Spreading examination of European corn borer (Ostrinia nubilalis Hbn.) flight types in the background of Peczely’s climate districts

Keszthelyi, S Nowinszky, L Puskas, J


European corn borer (ECB) flight and ecotype spread examinations were made in Hungary with the help of catching results of 44 agricultural Jermy light traps (2004). We wondered about alteration of flight types spread borderline as a function of global climate change. Catching data were evaluated by simple mathematical proportional numbers. Catching results originating from different points of the country were compared with Walter-Lieth climate diagram (2004) and Peczely’s Hungarian climate districts. Latter was to reveal correlations of flight types and different climatic districts. The previously published flight alteration tendency of ECB (Keszthelyi 2003, 2004b) continued in 2004. Generation quotients proved this process too. Average generation quotient of populations in South-eastem Hungary was 6, and the top of the same rate in this district was 10,84. The earlier observed ,,one peak flight” type was replaced by,two peaks flight” type in North-western Hungary (average generation quotient of this district: 2,5). The IRIN (relative individual number per one day) shows regressive tendency from South-eastem Hungary to North-westem Hungary (1RIN of 1.district: 6,99; 1RIN of 4.district: 4,69; 1RIN of 10.district: 2,78), but unequivocal conclusions cannot be drawn from these values for places of ecotypes. There is no unambiguous connection between Peczely’s Hungarian climate districts and spread of ECB flight types as proved by the statistical examinations.

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Analysis of features of climate change of Huabei area and the global climate change based on heuristic segmentation algorithm

Gong, ZQ Feng, GL Wan, SQ Li, JP


Global change science is a new research field, and one of the most important topics of which is the climate change study, to which great importance is attached by all governments of the world, and climatic abrupt change is one of manifestations of climate changes. Nowadays, research of climate change is mainly based on climatic proxy using traditional statistical method. However, climatic system is nonlinear, non-stationary and hierarchical, which makes even harder to detect and analyze abrupt climate changes. As well known, climatic system is made up of several sub-systems, and there may be inherent connections between them; however, there is only a few research methods and theories in this field. This article introduces a new detecting method I the heuristic segmentation algorithm, which is well fitted to nonlinear and non-stationary time series. Then, dealing with northern hemisphere tree rings and Beijing stalagmite based on high and low frequency series, we try to distinguish abrupt changes in different scales and disclose its physial mechanism. Defining a new physical quantity, the abrupt density, and analyzing the distribution characteristics of abrupt changes before and after 1000 a, We take Huabei area’s climatic change as an example to explore the inherent connections between local and global areas.

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Hazardous emissions, global climate change and environmental precautions

Demirbas, A


It has been recognized worldwide that the utilization of an enormous amount of fossil fuel has created various adverse effects on the environment, including acid rain and global warming. An increase in average global temperatures of approximately 0.56 K has been measured over the past century. This increase is called global climate change or global warming. The gases with three or more atoms that have higher heat capacities than those of O-2 and N-2 cause the greenhouse effect. Carbon dioxide (CO2) is a main greenhouse gas associated with global climate change. Nitrous oxide (N2O), chlorofluorocarbons (CFCs), methane (CH4) are other important greenhouse gases. Collectively, they are projected to contribute, directly, about as much potential global warming over the next 60 years as CO2. Three trace gases, HFCs, PFCs, and SF6, would be regulated under the 1997 Kyoto Protocol because of their global warming potential and for their potential growth of concentrations in the atmosphere. HFCs have been widely approved as substitutes for CFCs.

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Soybean (Glycine max (L.) Merr.) growth and development response to CO2 enrichment under different temperature regimes

Heinemann, AB Maia, AD Dourado-Neto, D Ingram, KT Hoogenboom, C


The carbon dioxide (CO2) concentration of the global atmosphere has increased during the last decades. This increase is expected to impact the diurnal variation in temperature as well as the occurrence of extreme temperatures. This potentially could affect crop production through changes in growth and development that will ultimately impact yield. The objective of this study was to evaluate the effect of CO2 and its interaction with temperature on growth and development of soybean (Glycine max (L.) Merr., cv. Stonewall). The experiment was conducted in controlled environment chambers at the Georgia Envirotron under three different temperatures and two CO2 regimes. The day/night air temperatures were maintained at 20/15, 25/20 and 30/25 degrees C, while the CO2 levels were maintained at 400 and 700 ppm, resulting in six different treatments. Plants were grown under a constant irradiance of 850 mu moles m(-2) s(-1) and a day length of 12 h; a non-limiting supply of water and mineral nutrients were provided. Five growth analyses were conducted at the critical development stages V4, R3, R5, R6 and R8. No differences in start of flowering were observed as a function of the CO2 level, except for the temperature regime 25/20 degrees C, where flowering for the elevated CO2 level occurred 2 days earlier than for the ambient CO2 level. For aboveground biomass, an increase in the CO2 level caused a more vigorous growth at lower temperatures. An increase in temperature also decreased seed weight, mainly due to a reduction in seed size. For all temperature combinations, final seed weight was higher for the elevated CO, level. This study showed that controlled environment chambers can be excellent facilities for conducting a detailed growth analysis to study the impact on the interactive effect of changes in temperature and CO2 on soybean growth and final yield. (c) 2005 Elsevier B.V. All rights reserved.

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Oceans and human health: Emerging public health risks in the marine environment

Fleming, LE Broad, K Clement, A Dewailly, E Elmir, S Knap, A Pomponi, SA Smith, S Gabriele, HS Walsh, P


There has been an increasing recognition of the inter-relationship between human health and the oceans. Traditionally, the focus of research and concern has been on the impact of human activities on the oceans, particularly through anthropogenic pollution and the exploitation of marine resources. More recently, there has been recognition of the potential direct impact of the oceans on human health, both detrimental and beneficial. Areas identified include: global change, harmful algal blooms (HABs), microbial and chemical contamination of marine waters and seafood, and marine models and natural products from the seas. It is hoped that through the recognition of the inter-dependence of the health of both humans and the oceans, efforts will be made to restore and preserve the oceans. (c) 2006 Elsevier Ltd. All rights reserved.

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An overview of terrestrial sequestration of carbon dioxide: The United States Department of Energy’s fossil energy R&D program

Litynski, JT Klara, SM McIlvried, HG Srivastava, RD

CLIMATIC CHANGE 74:1-3 81-95

Increasing concentrations of CO2 and other greenhouse gases (GHG) in the Earth’s atmosphere have the potential to enhance the natural greenhouse effect, which may result in climatic changes. The main anthropogenic contributors to this increase are fossil fuel combustion, land use conversion, and soil cultivation. It is clear that overcoming the challenge of global climate change will require a combination of approaches, including increased energy efficiency, energy conservation, alternative energy sources, and carbon (C) capture and sequestration. The United States Department of Energy (DOE) is sponsoring the development of new technologies that can provide energy and promote economic prosperity while reducing GHG emissions. One option that can contribute to achieving this goal is the capture and sequestration of CO2 in geologic formations. An alternative approach is C sequestration in terrestrial ecosystsems through natural processes. Enhancing such natural pools (known as natural sequestration) can make a significant contribution to CO2 management strategies with the potential to sequester about 290 Tg C/y in U.S. soils. In addition to soils, there is also a large potential for C sequestration in above and belowground biomass in forest ecosystems. A major area of interest to DOE’s fossil energy program is reclaimed mined lands, of which there may be 0.63 x10(6)supercript stop ha in the U.S. These areas are essentially devoid of soil C; therefore, they provide an excellent opportunity to sequester C in both soils and vegetation. Measurement of C in these ecosystems requires the development of new technology and protocols that are accurate and economically viable. Field demonstrations are needed to accurately determine C sequestration potential and to demonstrate the ecological and aesthetic benefits in improved soil and water quality, increased biodiversity, and restored ecosystems. The DOE’s research program in natural sequestration highlights fundamental and applied studies, such as the development of measurement, monitoring, and verification technologies and protocols and field tests aimed at developing techniques for maximizing the productivity of hitherto infertile soils and degraded ecosystems.

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