THE POTENTIAL EFFECTS OF GLOBAL WARMING ON THE PRIMARY PRODUCTIVITY OF A SUBALPINE LAKE1

ABSTRACT Atmospheric scientists have predicted that large-scale climatic changes will result from increasing levels of tropospheric CO₂ We have investigated the potential effects of climate change on the primary productivity of Castle Lake, a mountain lake in Northern California. Annual algal productivity was modeled empirically using 25 years of limnological data in order to establish predictive relationships between productivity and the climatic variables of accumulated snow depth and precipitation. The outputs of monthly temperature and precipitation from three general circulation models (GCMs) of doubled atmospheric CO₂ were then used in the regression model to predict annual algal productivity. In all cases, the GCM scenarios predicted increased algal productivity for Castle Lake under cenditions of doubled atmospheric CO₂The primary cause of enhanced productivity was the increased length of the growing season resulting from earlier spring ice-out.     

Potential coastal impacts of contemporary changing climate on South Asian seas states

The threat of man-induced global change on the nations of the South Asian seas region varies from place to place because of differences in exposure to monsoons and stoms, differences in local tectonics and subsidence, and variations in air and sea climates. Because several nations are involved, some having subsistence budgets, and given the cost of deriving independently a comprehensive response to global change, the similarities and differences between national settings must be identified soon. These comparisons will form the basis for local response strategies: the similarities provide a basis for responses similar to that of other nations and the differences provide for local adaptation. That climate change on the South Asian coastal region will have an impact is certain: its economics, environment, and coastal land uses are dominated to a certain extent by this marine influence. The extent of these impacts, however, is uncertain. Accompanying global change will be changes in sea level, differences in storm climate, and altered precipitation patterns; science cannot define today what pattern these changes will take. Because global change is inevitable—although its magnitude, timing, and geographic distribution are unknown—the South Asian seas region should begin the appropriate research and planning studies to set forth a reasoned response to global change, for implementation when scientific evidence for global change is more quantitative.     

Model Computations on Sequestration of Carbon in Managed Forests and Wood Products under Changing Climatic Conditions in Finland

The aim of this study was to assess the effects of forest management on carbon sequestration in forests and wood products by using a gap-type forest model interfaced with a wood product model. The assessment is based on total carbon sequestration, i.e. the amount of carbon left in vegetation, litter, soil organic matter and products when the flows of carbon back to the atmosphere have been subtracted. Thirty mixed-species stands, representing medium fertility sites in southern Finland, were included in each simulation for 300 years under current climatic conditions and predicted conditions of changing climate. The average total balance for the first 100 years was higher in the unmanaged system than in the managed system, but for the second and third 100-year periods the results were clearly opposite. Differences in the total balance between the treatments were larger during the first 100 years than over the whole 300-year period. Under conditions of changing climate, differences in carbon sequestration between management options were more pronounced than under current climatic conditions. Under current climatic conditions with the 100-year time frame, the ratio between the total annual balance and annual gross production was 0·208–0·289. Over the whole 300 years, however, efficiency was much lower, 0·088–0·121. Under changing climatic conditions, efficiency was also lower, 0·182–0·252 and 0·081–0·096, respectively. Different management alternatives clearly produced different amounts of timber for the production process; under conditions of changing climate, timber production was substantially enhanced. However, total carbon storages at the end of the simulation varied less than timber production. In the managed system, the flow back into the atmosphere was largest from litter, 41–51% of the total outflow, the flow from vegetation was 23–28%, from soil organic matter 22–25%, emissions from products 1–7%, and emissions from landfills 0–3%. If emissions due to the use of machinery in timber harvesting and transportation were included, they made up only 0·03–0·33% of the total outflow.     

Joint implementation: Biodiversity and greenhouse gas offsets

One of the most pressing environmental issues today is the possibility that projected increases in global emissions of greenhouse gases from increased deforestation, development, and fossil-fuel combustion could significantly alter global climate patterns. Under the terms of the United Nations Framework Convention on Climate Change, signed in Rio de Janeiro during the June 1992 Earth Summit, the United States and other industrialized countries committed to balancing greenhouse gas emissions at 1990 levels in the year 2000. Included in the treaty is a provision titled Joint Implementation, whereby industrialized countries assist developing countries in jointly modifying long-term emission trends, either through emission reductions or by protecting and enhancing greenhouse gas sinks (carbon sequestration). The US Climate Action Plan, signed by President Clinton in 1993, calls for voluntary climate change mitigation measures by various sectors, and the action plan included a new program, the US Initiative on Joint Implementation. Wisconsin Electric decided to invest in a Jl project because its concept encourages creative, cost-effective solutions to environmental problems through partnering, international cooperation, and innovation. The project chosen, a forest preservation and management effort in Belize, will sequester more than five million tons of carbon dioxide over a 40-year period, will become economically selfsustaining after ten years, and will have substantial biodiversity benefits.     

THE TIGER IN THE DINING ROOM: DESIGNING AND EVALUATING INTEGRATED ASSESSMENTS OF ATMOSPHERIC CHANGE

Integrated assessments (IAs) and integrated assessment models (IAMs) arerecent responses to the inter-disciplinary challenges provided by complexglobal environmental issues such as atmospheric change. This paper discussesan array of integrated assessments, providing an overview of the role of IAsas bridges or foundations for epistemic communities. Formal as well associal, political, and ethical issues are presented. As well as a definition of anIA and an IAM, different forms and approaches of current or proposed IAsare reviewed. Particular stress is laid on the need to maintain the integrity ofthe diverse components of an IA. Finally, reference is made to the need tounderstand the underlying ethical and normative concerns that have promotedthe current interest in IA.     

小兴安岭过去5000年的泥炭δ~(13)C记录

小兴安岭植物体中δ13C不仅受区域湿度变化控制,也受温度变化控制。泥炭纤维素的δ13C曲线,较好地响应了小兴安岭地区过去5000年来气候,特别是温度和湿度的演变过程。5.1～3.0kaBP、3.0～1.8kaBP、1.8kaBP迄今,小兴安岭经历了3个千年尺度的气候波动,气候演变过程为温暖湿润→温凉较湿→冷凉较湿。在千年尺度的气候波动上,又叠加着百年尺度的气候变化,在3.0kaBP以来更为显著。相应的,泥炭发育也经历了从富营养、中营养到贫营养阶段。     

Climate Change and Local Pollution Effects – An Integrated Approach

Few studies on measures for mitigation of damage caused by man-made emissions to the environment have tried to consider all major effects. We illustrate the importance of an integrated approach by estimating costs and benefits of a proposed energy saving program for Hungary, originally designed to reduce CO2 emissions. The dominant benefit of implementing the program is likely to be reduced health damage from local pollutants. Also reduced costs of material damage and to a lesser extent vegetation damage contribute to make the net benefit considerable. Compared to the reduction in these local and regional effects, the benefits from reducing greenhouse gases are likely to be minor. Since local effects in general occur much earlier after measures have been implemented than effects of increased emissions of greenhouse gases, inclusion of local effects makes evaluation of climate policy less dependent on the choice of discount rate. In our opinion, similar results are likely for many measures originally designed to reduce emissions of greenhouse gases particularly in some areas in developing countries with high local pollution levels. Main uncertainties in the analysis, e.g. in the relationships between damage and pollution level, are discussed.     

再制造工程——末端产品最佳资源化方式

再制造工程是一种末端产品的资源化利用方式。阐述了再制造工程的内涵、在全生命周期中的地位及国内外发展现状，分析了再制造所能够带来的巨大的资源效益、经济效益、社会效益和环境效益，得出结论：再制造工程是末端产品进行资源化处理的最佳利用方式。     

Climate Change Projections for the United States Midwest

Environmental and societal factors such asair quality, water quality andavailability, land use changes andexpanding urbanization are alreadyaffecting human health and welfare,agriculture, and natural ecosystems in theMidwestern United States. Over thiscentury, these existing stresses willlikely be exacerbated by climate changesresulting from human activities. It isessential that policy decisions aimed atpreserving the well-being of a region beinformed by a good understanding of theregion's climate, how climate might change,and the uncertainties inherent in futureprojections. Recent updates in climatemodeling expertise and an expanded view ofpossible non-intervention emissionscenarios have narrowed the range of changethat can be expected over the Midwestthroughout the next century in some ways,while broadening it in others. In contrastto previous studies, which generallyconsider a mid-range scenario for futureemissions, this study presents the range ofchange that would result from low to highscenarios for climate change. In this waywe account for uncertainties inanthropogenic forcing on climate change inthe region and quantify the potentialeffects of human actions on future climate.This analysis also combines the latestclimate model projections with historicalrecords of observed climate over the pastcentury, effectively placing potentialchanges in extreme event frequencies suchas heavy rainfall events and temperaturethreshold exceedances within the context ofobserved variability over the past century.The purpose of this study is to provide anupdated picture of the potential impacts ofclimate change on the Midwest to inform theimpact assessment and policy developmentcommunity. From the magnitude of thechanges projected by this study, it isclear that these must be included in futurepolicy decisions in order to ensure thesuccessful adaptation and survival ofexisting human and natural systems in theMidwest.     

铁路工程建设可持续发展战略的研究

提出了铁路建设走可持续发展之路，论证了铁路工程建设、环境与地质灾害三者的相互关系，阐述了在铁路工程建设的各个环节树立环境保护和防灾减灾的重要性。