大同市土地退化现状与动态变化研究

通过对大同市水土流失现状与动态变化、土地盐渍化和耕地数量与质量情况动态变化、土地沙漠化现状与动态变化的现状调查来分析大同市土地退化的主要成因以及采取的环境保护对策与建议.     

奈曼旗沙漠化土地动态变化分析

本文利用两期TM卫片对奈曼旗五个苏木的沙漠化土地动态进行了分析。10年间沙漠伦土地总面积减少了457.82km^2，但同期耕地面积净增加了394.08km^2；同时，流动沙地面积增加了139.62km^2，图斑数降低到了50％，流动沙地明显扩展，斑块间发生合并，集中连片的趋势严峻。不同苏木沙漠化土地变化表明，土地利用方式对其有明显影响。     

Climate Change and Energy Technologies

The long time scale of the climate change problem and the inherent nature of the carbon cycle bring important implications for present technology development efforts. Even if major technology improvements are achieved for non-carbon-emitting technologies such as energy-intensity improvements, wind, solar, biomass, and nuclear over the course of the 21^st century, most examinations of potential future greenhouse emissions conclude that additional technology development will be required to stabilize greenhouse gas concentrations. The evelopment of an expanded suite of technologies including carbon capture and disposal, hydrogen systems and biotechnology hold the potential to dramatically reduce the cost of stabilizing greenhouse gas concentrations. This paper examines these technologies in the context of a global integrated assessment model of energy, agriculture, land-use, economics, and carbon cycle processes.     

低纬高原地区城市化对室内外气温的影响

以低纬高原城市昆明市为研究对象,通过比较分析,得出以下结论昆明地区受全球气候变暖影响年平均气温约升高0.5℃/a左右;由于城市面积扩大导致昆明的室内外气温均升高,其中室内气温升高幅度大于室外气温,干季大于雨季;不论是干季还是雨季,城市增温效应与城市建成区面积、城市人口均有较好的相关关系.城市建成区面积增加对平均气温的影响较大;而城市人口增加对平均室内气温的影响较大.城市建成区面积每增加1km2,年平均室内气温将升高0.0054℃;年平均气温升高0.012℃.而城市人口增加1 万人,年平均室内气温升高0.0259℃;年平均气温升高0.0098℃.     

Scale,context, and decision making in agricultural adaptation to climate variability and change

This work presents a framework for viewing agricultural adaptation, emphasizing the multiple spatial and temporal scales on which individuals and institutions process information on changes in their environment. The framework is offered as a means to gain perspective on the role of climate variability and change in agricultural adaptation, and developed for a case study of Australian agriculture. To study adaptation issues at the scale of individual farms we developed a simple modelling framework. The model highlights the decision making element of adaptation in light of uncertainty, and underscores the importance of decision information related to climate variability. Model results show that the assumption of perfect information for farmers systematically overpredicts adaptive performance. The results also suggest that farmers who make tactical planting decisions on the basis of historical climate information are outperformed by those who use even moderately successful seasonal forecast information. Analysis at continental scales highlights the prominent role of the decline in economic operating conditions on Australian agriculture. Examples from segments of the agricultural industry in Australia are given to illustrate the importance of appropriate scale attribution in adapting to environmental changes. In particular, adaptations oriented toward short time scale changes in the farming environment (droughts, market fluctuations) can be limited in their efficacy by constraints imposed by broad changes in the soil/water base and economic environment occuring over longer time scales. The case study also makes the point that adaptation must be defined in reference to some goal, which is ultimately a social and political exercise. Overall, this study highlights the importance of allowing more complexity (limited information, risk aversion, cross-scale interactions, mis-attribution of cause and effect, background context, identification of goals) in representing adaptation processes in climate change studies.     

Influence of new town development on the urban heat island - The case of the Bundang area

Five new towns have been developed around the Seoul metropolitan area since 1996. However, these new towns generate lots of traffic and related problems in the areas including those new towns and Seoul as a result of increases in population and a lack of ecological-self-sufficiency. Currently, construction of another new town is under deliberation, and what should be a major consider is the notion that the new town be located within a wide, green zone. Many studies have revealed that green space can play an important role in improving urban eco-meteorological capability and air quality. In order to analyze the urban heat island which will be created by the new urban development, and to investigate the local thermal environment and its negative effects caused by a change of land use type and urbanization, Landsat TM images were used for extraction of urban surface temperature according to changes of land use over the last 15 years. These data are analyzed together with digital land use and topographic information. As a study result, it was found the urban heat island of the study area from 198.5 to 1999 rapidly developed which showed a difference of mean temperature above 2.0. Before the Bundang new town construction the temperature of the residential area was the same as a forest, but during the new town construction in 1991 analysis revealed the creation of an urban heat island. The temperature of a forest whose size is over 50% of the investigation area was lowest, and thus the presence of a forest is believed to have a direct cooling effect on the urban environment and its surroundings. The mean temperature of the residential and commercial areas in the study was found to be 4.5 higher than the forest, and therefore this part of land use is believed to be the main factor causing the temperature increase of the urban heat island.     

Interregional burden-sharing of greenhouse gas mitigation in the United States

Emissions trading is anattractive candidate for implementinggreenhouse gas mitigation, because it canpromote both efficiency and equity. Thispaper analyzes the interregional impacts ofalternative allocations of carbon dioxideemission permits within the U.S. Theanalysis is performed with the aid of anonlinear programming model for ten EPARegions and for six alternative permitdistribution formulas. The reason thatvarious alternatives need to be consideredis that there is no universal consensus onthe best definition of equity. Advanceknowledge of absolute and relative regionaleconomic impacts provides policy-makerswith a stronger basis for making thechoice. The analysis yields several usefulresults. First, the simulations indicatethat no matter how permits are allocated,this policy instrument can substantiallyreduce the cost of GHG mitigation for theU.S. in comparison to a system of fixedquotas for each of its regions. Interestingly, the welfare impacts ofseveral of the allocation formulas differonly slightly despite the large differencesin their philosophical underpinnings. Also, the results for some equity criteriadiffer greatly from their application inthe international domain. For example, theEgalitarian (per capita) criterion resultsin the relatively greatest cost burdenbeing incurred by one of the regions of theU.S. with the lowest per capita income.     

Unemployment effects of climate policy

This paper models the unemployment effects of restrictions on greenhouse gas emissions, embodying two of the most significant types of short-term economic imperfections that generate unemployment: sectoral rigidities in labor mobility and sectoral rigidities in wage adjustments. A labor policy is also analyzed that would reduce the direct negative economic effects of the emissions restrictions.The politics of limiting greenhouse gas emissions are often dominated by relatively short-term considerations. Yet the current economic modeling of emissions limitations does not embody economic features that are likely to be particularly important in the short term, in particular, the politically sensitive unemployment rate. Moreover, only a few of these studies also consider policies that would offset the negative direct economic effects of emissions restrictions. For plausible estimates of the parameters, the model shows that, with the labor market imperfections, if there were no offsetting policies, the reductions in GNP in the U.S. in the first 10 years after emissions restrictions were imposed would be as much as 4%. However, if there were two policies, instead of just one: a counteracting labor market policy, as well as the emissions restrictions, the negative direct economic effects could be completely eliminated.     

全球环境问题与当代国际关系

环境问题使人类面临着前所未有的生存与发展的巨大挑战，也深刻影响着当代国际关系的发展和演变。该文对环境问题引起的国家安全，全球环境问题的南北分歧，以及南北矛盾的焦点等几个方面，分别进行了阐述和分析，随着环境总是的国际化和全球化，国际社会把保护环境看成是各国政府的共同义务和责任，而与此同时国际间的环境合与竞争关系也得到了进一步的发展。