Abstracts on Global Climate Change

Nov 2005

Fine-scale predictions of distributions of Chagas disease vectors in the state of Guanajuato, Mexico

Lopez-Cardenas, J Bravo, FEG Schettino, PMS Solorzano, JCG Barba, ER Mendez, JM Sanchez-Cordero, V Peterson, AT Ramsey, JM


One of the most daunting challenges for Chagas disease surveillance and control in Mexico is the lack of community level data on vector distributions. Although many states now have assembled representative domestic triatomine collections, only two triatomine specimens bad been collected and reported previously from the state of Guanajuato. Field personnel from the state’s Secretaria de Salud conducted health promotion activities in 43 of the 46 counties in the state and received donations of a total of 2,522 triatomine specimens between 1998 and 2002. All specimens were identified, and live insects examined for Trypanosoma cruzi. In an effort to develop fine-scale distributional data for Guanajuato, collection localities were georeferenced and ecological niches were modeled for each species by using evolutionary-computing approaches. Five species were collected: Triatoma mexicana (Herrich-Schaeffer), Triatoma longipennis (Usinger), Triatoma pallidipennis (Stal), Triatoma barberi (Usinger), and Triatoma dimidiata (Latreille) from 201 communities located at elevations of 870 - 2,200 m. Based on collection success, T mexicana had the broadest dispersion, although niche mapping indicates that T barberi represents the greatest risk for transmission of Chagas disease in the state. T dimidiata was represented in collections by a single adult collected from one village outside the predicted area for all species. For humans, In estimated 3,755,380 individuals are at risk for vector transmission in the state, with an incidence of 3,500 new cases per year; overall seroprevalences of 2.6% indicate that 97,640 individuals are infected with T cruzi at present, including 29,300 chronic cases.

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Fine-scale processes regulate the response of extreme events to global climate change

Diffenbaugh, NS Pal, JS Trapp, RJ Giorgi, F


We find that extreme temperature and precipitation events are likely to respond substantially to anthropogenically enhanced greenhouse forcing and that fine-scale climate system modifiers are likely to play a critical role in the net response. At present, such events impact a wide variety of natural and human systems, and future changes in their frequency and/or magnitude could have dramatic ecological, economic, and sociological consequences. Our results indicate that fine-scale snow albedo effects influence the response of both hot and cold events and that peak increases in extreme hot events are amplified by surface moisture feedbacks. Likewise, we find that extreme precipitation is enhanced on the lee side of rain shadows and over coastal areas dominated by convective precipitation. We project substantial, spatially heterogeneous increases in both hot and wet events over the contiguous United States by the end of the next century, suggesting that consideration of fine-scale processes is critical for accurate assessment of local- and regional-scale vulnerability to climate change.

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Trace metal analysis in arctic aerosols by an inductively coupled plasma-time of flight-mass spectrometer combined with an inductively heated vaporizer

Ludke, C Skole, J Taubner, K Kriews, M


Two newly developed instruments were combined to analyze the trace metal content in size separated arctic aerosols during the measurement campaign ASTAR 2004 (Arctic Study of Tropospheric Aerosols, Clouds and Radiation 2004) at Spitsbergen in May-June 2004. The aim of this extensive aerosol measurement campaign was to obtain a database for model-calculations of arctic aerosol, which play an important role in the global climate change. The ASTAR project was centered on two aircraft measurement campaigns, scheduled from 2004 to 2005, addressing both aerosol and cloud measurements, combined with ground-based and satellite observations. In the present paper one example for the analysis of ground-based aerosol particles is described. The sampling of aerosol particles was performed in a well-known manner by impaction of the particles on cleaned graphite targets. By means of a cascade impactor eight size classes between 0.35 and 16.6 mu m aerodynamic diameters were separated. To analyze the metal content in the aerosol particles the targets were rapidly heated up to 2700 degrees C in an inductively heated vaporizer system (IHVS). An argon flow transports the vaporized sample material into the inductively coupled plasma (ICP) used as ionization source for the time of flight-mass spectrometer (TOF-MS). The simultaneous extraction of the ions from the plasma, as realized in the TOF instrument, allows to obtain the full mass spectrum of the sample during the vaporization pulse without any limitation in the number of elements detected. With optimized experimental parameters the element content in arctic aerosol particles was determined in a mass range between Li-7 and Bi-209. Comparing the size distribution of the elemental content of the aerosol particles, two different meteorological situations were verified. For calibration acidified reference solutions were placed on the cleaned target inside the IHVS. The limits of detection (LOD) for the element mass on the target range between 2 and 200 pg for the elements studied, except Na, Mg, and Cr, which are influenced by high background. (c) 2005 Elsevier B.V. All rights reserved.

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Global climate change and the equity-efficiency puzzle

Manne, AS Stephan, G

ENERGY 30:14 2525-2536

There is a broad consensus that the costs of abatement of global climate change can be reduced efficiently through the assignment of quota rights and through international trade in these rights. There is, however, no consensus on whether the initial assignment of emissions permits can affect the Pareto-optimal global level of abatement. This paper provides some insight into the equity-efficiency puzzle. Qualitative results are obtained from a small-scale model; then quantitative evidence of separability is obtained from MERGE, a multiregion integrated assessment model. It is shown that if all the costs of climate change can be expressed in terms of GDP losses, Pareto-efficient abatement strategies are independent of the initial allocation of emissions rights. This is the case sometimes described as ‘market damages’. If, however, different regions assign different values to nonmarket damages such as species losses, different sharing rules may affect the Pareto-optimal level of greenhouse gas abatement. Separability may then be demonstrated only in specific cases (e.g. identical welfare functions or quasi-linearity of preferences or small shares of wealth devoted to abatement). (c) 2004 Elsevier Ltd. All rights reserved.

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From regional to global dynamics structure of the climatic proxy

Wan, SQ Feng, GL Dong, WJ Li, JP

ACTA PHYSICA SINICA 54:11 5487-5493

Global change science is a new research domain nowadays, and one of the most important studies of which is the climate change,to which great attention is paid by all governments in world. It is mainly based on the climatic proxy that we can study the past climate change. Although many achievements have been obtained, majority of the results are limited to the external characteristics of the proxy due to lagged analysis methods. For example, we judge if the climate is flood/drought or cold/warm through linear trend of the time series, however, we do not know whether it is a natural variation or the result of external forces, the mechanism is not uncovered. Because complexity of the open global climate system, there are different characteristics among the climatic proxies from different region of the world, from which it is difficult to reveal the intrinsic general principles i.e. the globality. For the further study on the past climate change, especially to reveal the rules of the global climate change in past 2000a and predict future climate change, a new method making use of the dynamical lag correlation exponent (named Q index in the text), a dynamics exponent based on the phase-space reconstruction, is introduced in this paper, which can effectively discern the similarities or differences between the dynamics of the two series. With Q index, we analyze the dynamics structure of some typical climatic proxies. The results show that the dynamics of climatic proxies are almost similar, and the regional climate keeps the same change with the global. In other words, regional climate is controlled by the global climate change. Besides, there are two dynamics jump periods (namely 700-900a and 1300-1700a) in past 2000a of the climate system, which may correspond to the periods of the medieval warm period and the little ice age, respectively.

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Flood risk, uncertainty, and scientific information for decision making - Lessons from an interdisciplinary project

Morss, RE Wilhelmi, OV Downton, MW Gruntfest, E


The magnitude of flood damage in the United States, combined with the uncertainty in current estimates of flood risk, suggest that society could benefit from improved scientific information about flood risk. To help address this perceived need, a group of researchers initiated an interdisciplinary study of climate variability, scientific uncertainty, and hydrometeorological information for flood-risk decision making, focused on Colorado’s Rocky Mountain Front Range urban corridor. We began by investigating scientific research directions that were likely to benefit flood-risk estimation and management, through consultation with climatologists, hydrologists, engineers, and planners. In doing so, we identified several challenges involved in generating new scientific information to aid flood management in the presence of significant scientific and societal uncertainty. This essay presents lessons learned from this study, along with our observations on the complex interactions among scientific information, uncertainty, and societal decision making. It closes by proposing a modification to the “end to end” approach to conducting societally relevant scientific research. Although we illustrate points using examples from flood management, the concepts may be applicable to other arenas, such as global climate change.

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Refugial forests of the southern Appalachians: photosynthesis and survival in current-year Abies fraseri seedlings

Johnson, DM Smith, WK

TREE PHYSIOLOGY 25:11 1379-1387

Fraser fir (Abies fraseri (Pursh) Poiret) is an endemic, high-elevation conifer confined to six relict mountain-top communities in the southern Appalachian Mountains, USA. High adult mortality has occurred over the past 50 years, possibly the result of an introduced insect (Adelges piceae Ratzeburg), air pollution, or both. Knowledge of the mechanisms of and limitations to seedling establishment may allow reestablisment and perpetuation of this unique community type, notwithstanding global climate change. We monitored seedling emergence and mortality in relation to photosynthetic performance and water relations in microsites differing in canopy openness (sunlight exposure) over the summer of 2004. Abundance of cotyledonous seedlings in early summer was 2.3 times greater (849 versus 366 seedlings m(-2)) in microsites with lower sky exposure (greater canopy closure) than in microsites with greater sky exposure (greater canopy openness). In contrast, late-season abundance and survival were greater in areas beneath more open canopies than in areas beneath less open canopies (3.3 times and 11.7 times greater, respectively). However, newly emerged seedling survival in a completely open site (no overhead canopy) was zero, despite an initial density of 124 seedlings m(-2). Seedling water status was similar in open- and closed-canopy sites (-0.52 and -0.74 MPa, respectively). Photosynthetic carbon gain was higher in newly emerged seedlings at open canopy than at closed canopy sites, especially during early morning. Based on photosynthetic light response curves and measured sunlight regimes, seedlings in open canopy sites were estimated to assimilate 3.3-4.5 times more carbon than seedlings at closed sites. Reductions in carbon gain of closed-site seedlings, primarily a result of limited sunlight, corresponded to substantial increases in seedling mortality (98 versus 79% in open canopy sites). Thus, sunlight exposure, which reflects overstory canopy structure, appears to be an important factor influencing newly emerged seedling survival and distribution.

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Direct constraints on Antarctic Peninsula Ice Sheet grounding events between 5.12 and 7.94 Ma

Bart, PJ Egan, D Warny, SA


How has the Antarctic Ice Sheet responded to or influenced global climate change? This simple question has been difficult to address because the long-term records of the ice sheet’s fluctuations are poorly constrained with geologic data from Antarctica. Thus studies to date have not convincingly established how specific Antarctic Ice Sheet events correlate with climatic, eustatic, or other phenomena known from low-latitude and deep-sea records. This study focused on documenting the direct record of ice sheet advance and retreat to the Antarctic Peninsula’s shelf edge. On the peninsula’s outer shelf, seismic reflectors interpreted to be subglacial unconformities were correlated with published results from Ocean Drilling Program Leg 178. Lithologic and chronologic control at two drill sites provided ground truth for the seismic interpretation and the timing of the Antarctic Peninsula Ice Sheet grounding events. This synthesis showed that grounded ice advanced to the shelf edge on at least 12 occasions between 5.12 and 7.94 Ma.

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Variation of karst spring discharge in the recent five decades as an indicator of global climate change: A case study at Shanxi, northern China

Guo, QH Wang, YX Ma, T Li, LX


Karst in Shanxi Province is representative of that in northern China, and karst water systems discharge in the form of springs that are among the most important sources for local water supply. Since the 1950s, attenuation has been the major trend of discharge variation of most karst springs at Shanxi. Based on the case study of 7 karst springs including Niangziguan, Xin’an, Guozhuang, Shentou, Jinci, Lancun, and Hongshan springs, the discharge variation process of karst springs was divided into natural fluctuation phase and anthropogenic impact phase. Discharge attenuation of the 7 karst springs was controlled mainly by climate and human activities, with their contributions being respectively about 60% and 40%. According to the difference of the effect of climate and human activities for each spring, attenuation modes of spring discharge fall into three types: natural process dominated attenuation type, exploitation induced process dominated attenuation type, and mixed attenuation type. The total restored discharge variation of 7 karst springs matched well with the global air temperature change in 1956-2000, clearly indicating the trend of global warming and aridity in the last several decades, and the analysis of discharge variation processes of karst springs can be used as a new tool for global change studies.

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A model to predict climate-change impact on fish catch in the world oceans

Biswas, BK Svirezhev, YA Bala, BK


Water temperature plays a very important role in fish production. The assessment of the impact of water-temperature changes on fish catches in world fishery is essential for the sustainable management of world fishery resources. Fish catch includes different species, but using information analysis, it is shown that total fish catch can be used without significant loss of information about the dynamic properties of the system. A new method for the forecasting of the fish catch of the major fishing areas in the world’s oceans under global climate change (temperature) has been developed. This method predicts the tendency (increase or decrease) for fish catch, with quantitative predictor’s power, if the temperature is known. This method has been applied to the Indian Ocean to assess the climate-change impact on fish catch. Based on the temperatures predicted using the CLIMate-BiospheRE model for the years 2000-2100, a decrease of fish catch in the Indian Ocean, with the confidence of the predictor’s power at >= 90%, has been predicted.

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Soil carbon sequestration for sustaining agricultural production and improving the environment with particular reference to Brazil

Lal, R


Agricultural ecosystems generally contain less soil organic carbon (SOC) pool than their potential capacity because of the low return and high rate of mineralization of biosolids, and severe losses due to accelerated erosion and leaching. Conversion of natural to agricultural ecosystems usually causes depletion of 50 to 75 percent of the antecedent SOC pool, thereby creating a potential sink capacity of as much as 35 to 40 Mg C/ha. The depletion of SOC pool leads to decline in soil quality and resilience with attendant reduction in biomass productivity, decreased capacity to degrade and filter pollutants, increased risks of soil degradation by erosion and other processes, and increase in emission of greenhouse gases (GHGs). The magnitude of depletion of SOC pool is greater for soils of the tropics than temperate regions, and for farms which are resource-based and managed with low-input than those managed with science-based and judicious off-farm inputs. The SOC sequestration, increasing SOC pool through conversion to an appropriate land use and adoption of recommended management practices (RMPs), can reverse soil degradation trends, improve soil quality and resilience, increase biomass production and decrease emission of GHGs. A strong link exists between the labile fraction of SOC pool and soil biodiversitythe activity and species diversity of soil fauna (micro, meso and macro) and micro-organisms. Soil biodiversity is usually higher under pastures and planted fallow systems than under crops, and is likely to increase with adoption of conservation tillage and mulch farming, integrated nutrient management and manuring, mixed farming systems and integrated pest management (IPM) techniques. The gross rates of SOC sequestration through adoption of RMPs range from 400 to 800 kg/ha/y for cool and humid regions and 100 to 200 kg/ha/y for dry and warm climates. The potential of soil C sequestration in Brazil is estimated at about 50 Tg C/y. In addition, 60 Tg C/y emitted by erosion-induced mineralization can also be avoided through effective erosion control measures.

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Climate changes and tree phylogeography in the Mediterranean

Petit, RJ Hampe, A Cheddadi, R

TAXON 54:4 877-885

The Mediterranean Basin is expected to be more strongly affected by ongoing global climate change than most other regions of the earth. Given the magnitude of forecasted trends, there are great concerns for the particularly rich biodiversity found in the region. Studies of the consequences of past climate shifts on biodiversity represent one of the best sources of data to validate models of the ecological and evolutionary consequences of future changes. Here we review recent findings from palaeoecology, phylogeography and climate change research to (1) explore possible antecedents of the predicted climate warming in the younger geological history of the Mediterranean Basin, (2) assess how tree populations have reacted to them, and (3) evaluate the significance of the evolutionary heritage that is at stake. A major question of our retrospective approach is whether Quaternary tree extinctions took place primarily during glacial or during interglacial episodes. Available data are scanty and somewhat conflicting. In contrast, abundant phylogeographic evidence clearly indicates that the bulk of genetic diversity in European temperate tree species is almost invariably located in the southernmost part of their range. Long-term persistence of isolated populations have been common phenomena in the Mediterranean, to the point that the current genetic structure in this area probably often reflects population divergence that pre-dates the onset of the Mediterranean climate in the Pliocene. In particular, Tertiary migrations into the Mediterranean of tree taxa originating from Asia seem to have left their footprints in the current genetic structure in these slowly evolving organisms. Moreover, phylogeographic studies point to heterogeneous rates of molecular evolution across lineages that are inversely related with their stability. We conclude that relict tree populations in the Mediterranean Basin represent an evolutionary heritage of disproportionate significance for the conservation of European plant biodiversity.

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