|Abstracts on Global Climate Change|
Surface air temperature variability over Turkey and its connection to large-scale upper air circulation via multivariate techniques
Tatli, H Dalfes, HN Mentes, SS
INTERNATIONAL JOURNAL OF CLIMATOLOGY 25:3 331-350
The problem of statistical linkages between large-scale and local-scale processes is investigated through noise reduction by singular spectrum analysis (SSA) and spatial principal component analysis in order to construct appropriate statistical models for estimating the local-scale climate variables from large-scale climate processes. This paper presents an approach for downscaling monthly temperature series over Turkey by upper air circulations derived from the National Centers for Environmental Prediction-National Center for Atmospheric Research Reanalysis data sets (500 hPa geopotential heights and 500-1000 hPa thicknesses). The proposed approach consists of three stages. First, the available data sets are separated into deterministic, statistical components and random components by SSA. Second, the deterministic components are saved and the random components are eliminated by spatial principal component analysis. Subsequently, the statistical components are combined with the deterministic components constituting a noise-free data set. Furthermore, so-called Sampson correlation patterns are determined between the noise-free large-scale and the local-scale variables for interpreting the large-scale process impacts on local-scale features. Third, the significant redundancy variates based on canonical correlation analysis are extracted in order to identify the statistical downscaling model for temperature series of 62 stations in Turkey. The results show that the interpretation of the local-scale processes with the noise-free data sets is more significant than with the raw data sets. Copyright (c) 2005 Royal Meteorological Society.
Temperature dependence of carbon-13 kinetic isotope effects of importance to global climate change
Lin, H Zhao, Y Ellingson, BA Pu, JZ Truhlar, DG
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127:9 2830-2831
Comparison of climate space and phylogeny of Marmota (Mammalia : Rodentia) indicates a connection between evolutionary history and climate preference
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 272:1562 519-526
Palaeobiologists have investigated the evolutionary responses of extinct organisms to climate change, and have also used extinct organisms to reconstruct palaeoclimates. There is evidence of a disconnection between climate change and evolution that suggests that organisms may not be accurate palaeoclimate indicators. Here, marmots (Marmota sp.) are used as a case study to examine whether similarity of climate preferences is correlated with evolutionary relatedness of species. This study tests for a relationship between phylogenetic distance and ‘climate distance’ of species within a clade. There should be a significant congruence between maximum likelihood distance and standardized Euclidian distance between climates if daughter species tend to stay in environments similar to parent species. Marmots make a good test case because there are many extant species, their phylogenies are well established and individual survival is linked to climatic factors. A Mantel test indicates a significant correlation between climate and phylogenetic distance matrices, but this relationship explains only a small fraction of the variance (regression R-2 = 0.114). These results suggest that (i) closely related species of marmots tend to stay in similar environments; (ii) marmots may be more susceptible than many mammals to global climate change; and (iii) because of the considerable noise in this system, the correlation cannot be used for detailed palaeoclimate reconstruction.
Synergistic effects associated with climate change and the development of rocky shore molluscs
Przeslawski, R Davis, AR Benkendorff, K
GLOBAL CHANGE BIOLOGY 11:3 515-522
Global climate change and ozone layer thinning will simultaneously expose organisms to increasingly stressful conditions. Early life stages of marine organisms, particularly eggs and larvae, are considered most vulnerable to environmental extremes. Here, we exposed encapsulated embryos of three common rocky shore gastropods to simultaneous combinations of ecologically realistic levels of ultraviolet radiation (UVR), water temperature stress and salinity stress to identify potential interactions and associated impacts of climate change. We detected synergistic effects with increases in mortality and retardation in development associated with the most physiologically stressful conditions. The effects of UVR were particularly marked, with mortality increasing up to 12-fold under stressful conditions. Importantly, the complex outcomes observed on applying multiple stressors could not have been predicted from examining environmental variables in isolation. Hence, we are probably dramatically underestimating the ecological impacts of climate change by failing to consider the complex interplay of combinations of environmental variables with organisms.
Effects of large-scale climatic fluctuations on survival and production of young in a Neotropical migrant songbird, the yellow warbler Dendroica petechia
Mazerolle, DF Dufour, KW Hobson, KA den Haan, HE
JOURNAL OF AVIAN BIOLOGY 36:2 155-163
Migrant songbirds are vulnerable to changes in climatic conditions on both the breeding and wintering grounds. For North American Neotropical migrants, the El Nino/Southern Oscillation (ENSO), via its effects on global precipitation and temperature, modulates the productivity of their temperate and tropical terrestrial ecosystems used during the course of their annual cycle. We evaluated how a densely nesting population of yellow warblers Dendroica petechia in a riparian forest in southern Manitoba, Canada, responded to the El Nino/Southern Oscillation (ENSO) between 1992 and 2001. Standardized mist netting was used to estimate apparent annual survival of adults and production of young. Both adult survival and the production of young were positively correlated with the Southern Oscillation Index (SOI). More specifically, values of both these demographic parameters were lowest during El Nino years and highest during La Nina years. These findings demonstrate the influence of climate on populations of Neotropical migrants in North America. The more frequent El Ninos predicted to result from future global climate change could negatively affect populations of yellow warblers and other Neotropical migrants breeding in this region.
Rainfall exclusion in an eastern amazonian forest alters soil water movement and depth of water uptake
Romero-Saltos, H Sternberg, LDSL Moreira, MZ Nepstad, DC
AMERICAN JOURNAL OF BOTANY 92:3 443-455
Deuterium-labeled water was used to study the effect of the Tapajos Throughfall Exclusion Experiment (TTEE) on soil moisture movement and on depth of water uptake by trees of Coussarea racemosa, Sclerolobium chrysophyllum, and Eschweilera pedicellata. The TTEE simulates an extended dry season in an eastern Amazonian rainforest, a plausible scenario if the El Nino phenomenon changes with climate change. The TTEE excludes 60% of the wet season throughfall from a 1-ha plot (treatment), while the control 1-ha plot receives precipitation year-round. Mean percolation rate of the label peak in the control plot was greater than in the treatment plot during the wet season (0.75 vs. 0.07 m/mo). The rate was similar for both plots during the dry season (ca. 0. 15 m/mo), indicative that both plots have similar topsoil structure. Interestingly, the label peak in the control plot during the dry season migrated upward an average distance of 64 cm. We show that water probably moved upward through soil pores-i.e., it did not involve roots (hydraulic lift)-most likely because of a favorable gradient of total (matric + gravitational) potential coupled with sufficient unsaturated hydraulic conductivity. Water probably also moved upward in the treatment plot, but was not detectable; the label in this plot did not percolate below 1 m or beyond the depth of plant water uptake. During the dry season, trees in the rainfall exclusion plot, regardless of species, consistently absorbed water significantly deeper, but never below 1.5-2 m, than trees in the control plot, and therefore may represent expected root function of this understory/subcanopy tree community during extended dry periods.
One- and three-hour PM2.5 characterization, speciation, and source apportionment using continuous and integrated samplers
Long, RW Modey, WK Smith, PS Smith, R Merrill, C Pratt, J Stubbs, A Eatough, NL Eatough, DJ Malm, WC Wilson, WE
AEROSOL SCIENCE AND TECHNOLOGY 39:3 238-248
Ammonium nitrate and semivolatile organic compounds (SVOC) are significant components of fine particles in many urban atmospheres. These components, however, are not properly measured by current EPA accepted methods, such as the R&P TEOM monitor, due to loss of semivolatile material (SVM) from particles in the heated environment of the filter during sampling. The accurate determination of semivolatile material is important due to the possible effects of these species on human health, visibility, and global climate change. The concentration and composition of fine particulate material were determined using a combination of continuous and integrated samplers at the Brigham Young University-EPA Environmental Monitoring for Public Access and Community Tracking (BYU-EPA EMPACT) monitoring site in Salt Lake City, Utah over a six-day sampling period (30 January to 4 February) during the winter of 2001. Continuous samples were collected using a RAMS (total PM2.5 mass), a TEOM monitor (nonvolatile PM2.5 mass), an Aethalometer (elemental carbon), a TSI CPC (particle count), and a Nephelometer (light scattering by particles, bsp). Fine particle composition and mass were determined on a three-hour basis using the PC-BOSS diffusion denuder sampler. Total PM2.5 mass-determined with the RAMS agreed with constructed mass determined from the chemical composition measured in collocated PC-BOSS-integrated samples. Results from this study indicate that semivolatile material (ammonium nitrate and semivolatile organic compounds) is a significant component of fine particle mass. Semivolatile organic compounds were the major contributor to light scattering during the six-day sampling period. Semivolatile nitrate, but not organic material, was suggested to be hygroscopic by the nephelometric data. The majority of the SVM observed appeared to be secondary material formed from photochemical reactions of the organic and NOx emissions from mobile sources and wood smoke combustion.
Relay cropping for improved air and water quality
Schepers, JS Francis, DD Shanahan, JF
ZEITSCHRIFT FUR NATURFORSCHUNG C-A JOURNAL OF BIOSCIENCES 60:3-4 186-189
Using plants to extract excess nitrate from soil is important in protecting against eutrophication of standing water, hypoxic conditions in lakes and oceans, or elevated nitrate concentrations in domestic water supplies. Global climate change issues have raised new concerns about nitrogen (N) management as it relates to crop production even though there may not be an immediate threat to water quality. Carbon dioxide (CO2) emissions are frequently considered the primary cause of global climate change, but under anaerobic conditions, animals can contribute by expelling methane (CH4) as do soil microbes. In terms of the potential for global climate change, CH4 is similar to 25 times more harmful than CO2. This differential effect is minuscule compared to when nitrous oxide (N2O) is released into the atmosphere because it is similar to 300 times more harmful than CO2. N2O losses from soil have been positively correlated with residual N (nitrate, NO3) concentrations in soil. It stands to reason that phytoremediation via nitrate scavenger crops is one approach to help protect air quality, as well as soil and water quality. Winter wheat was inserted into a seed corn/soybean rotation to utilize soil nitrate and thereby reduce the potential for nitrate leaching and N2O emissions. The net effect of the 2001-2003 relay cropping sequence was to produce three crops in two years, scavenge 130 kg N/ha from the root zone, produce an extra 2 Mg residue/ha, and increase producer profitability by similar to$ 250/ha.
Climate change impacts for the conterminous USA: An integrated assessment - Part 4: Water resources
Thomson, AM Brown, RA Rosenberg, NJ Srinivasan, R Izaurralde, RC
CLIMATIC CHANGE 69:1 67-88
Global climate change will impact the hydrologic cycle by increasing the capacity of the atmosphere to hold moisture. Anticipated impacts are generally increased evaporation at low latitudes and increased precipitation at middle and high latitudes. General Circulation Models (GCMs) used to simulate climate disagree on whether the U.S. as a whole and its constituent regions will receive more or less precipitation as global warming occurs. The impacts on specific regions will depend on changes in weather patterns and are certain to be complex. Here we apply the suite of 12 potential climate change scenarios, previously described in Part 1, to the Hydrologic Unit Model of the United States (HUMUS) to simulate water supply in the conterminous United States in reference to a baseline scenario. We examine the sufficiency of this water supply to meet changing demands of irrigated agriculture. The changes in water supply driven by changes in climate will likely be most consequential in the semi-arid western parts of the country where water yield is currently scarce and the resource is intensively managed. Changes of greater than +/-50% with respect to present day water yield are projected in parts of the Midwest and Southwest U.S. Interannual variability in the water supply is likely to increase where conditions become drier and to decrease under wetter conditions.
Summary of a workshop on the development of health models and scenarios: Strategies for the future
Ebi, KL Gamble, JL
ENVIRONMENTAL HEALTH PERSPECTIVES 113:3 335-338
A workshop was convened in July 2003 by the Global Change Research Program, Office of Research and Development at the U.S. Environmental Protection Agency, to review current strategies for developing human health models and scenarios in the context of global environmental change, particularly global climate change, and to outline a research agenda that effectively characterizes the interplay of global change with the health of human populations. The research agenda developed at the workshop focused on three issues: a) the development of health models, b) the development of health scenarios, and c) the use of health models and health scenarios to inform policy. The agenda identified research gaps as well as barriers to the development and use of models and scenarios. This report summarizes the workshop findings.
Soil carbon and the mitigation of global climate change
QUIMICA NOVA 28:2 329-334
SOIL CARBON AND THE MITIGATION OF GLOBAL CLIMATE CHANGE. The soils of the world contain more carbon than the combined total amounts occurring in vegetation and the atmosphere. Hence soils are a major reservoir of carbon in terrestrial ecosystems and an important sink. Recently, emphasis has been placed on the need to sequester carbon from atmospheric carbon dioxide into soil organic matter because of international concerns about greenhouse gas emissions and global climate change. The best strategies to built-up carbon stocks in the soil are basically those that increase the input of organic matter to the soil, and/or decrease the rate of soil organic matter decomposition. Grain crop systems based on soil ploughing and harrowing lead to Co-2 emissions combined with tremendous soil losses. In Brazil, no-tillage system was introduced to combat soil erosion by water and this soil management led to the build-up of soil carbon stocks with simultaneous high crop yields. However, the present procedure used to quantify carbon stocks in soils is laborious and of high cost. The use of infrared spectroscopy is very promising as an alternative low-cost method of soil carbon determination.
The Brazilian air transportation sector in the context of global climate change: CO2 emissions and mitigation alternatives
Simoes, AF Schaeffer, R
ENERGY CONVERSION AND MANAGEMENT 46:4 501-513
The purpose of this study is to discuss the participation of Brazilian air transportation within the context of global climate change. It first briefly presents an inventory of CO:! emissions caused by airborne activities in Brazil and then shows a trend projection through to 2023, indicating the progress of these emissions, with eight possible mitigation strategies. The abatement potential for each of these strategies is also investigated. It is estimated that joint implementation of all these strategies within a typical projection of broad based sustainability (based on renewable energy sources with fair social., economic and technological development) could result in an annual reduction in CO2 emissions caused by airborne activities in Brazil up to 28.5% (compared to the trend projection for 2023). It is also estimated that the emissions avoided through joint implementation of the mitigation alternatives analyzed may well reach 82,000 Gg (or 10(9) g) of CO2 from 2003 through 2023. (C) 2004 Elsevier Ltd. All rights reserved.