Modeling land use and cover as part of global environmental change

Land use and cover changes are important elements of the larger problem of global environmental change. Landuse patterns result in landcover changes that cumulatively affect the global biosphere and climate. We describe efforts to analyze the driving forces behind land transformations and to create land use models that can be linked to other types of global change models. Two efforts to model land use in the U.S. are reviewed. One projects aggregate agricultural, forest, and range land, and the other attempts to model forest land use change at the parcel scale in two mountain landscapes. We conclude with suggestions for new approaches that could clarify the role of land use/cover change in global change and in natural resources management.     

萍乡市土地利用变化及生态环境质量评价

文中基于2002、2007、2013和2018年Landsat遥感数据,采用支持向量机法提取了萍乡市的土地利用信息,通过提取绿度指标、干度指标、湿度指标和热度指标,利用主成分分析法构建萍乡市遥感生态指数(RSEI),分析了2002—2018年萍乡市的土地利用变化及生态环境情况.结果表明:1)2002—2018年建设用地持续增多,水域、林地和耕地先减后增,总体呈减少态势;草地先增后减,总体呈增加态势;未利用地先减后增,总体呈增加态势.2)2002—2018年萍乡市的生态环境以"一般"和"良好"为主,各区县的生态环境存在很大的差异性.3)林地、草地和水域位置的生态环境相对偏好,而建设用地和未利用地位置的生态环境相对偏差.     

Downscaling drivers of global environmental change: Enabling use of global SRES scenarios at the national and grid levels

Global environmental change scenarios typically distinguish between about 10–20 global regions. However, various studies need scenario information at a higher level of spatial detail. This paper presents a set of algorithms that aim to fill this gap by providing downscaled scenario data for population, gross domestic product (GDP) and emissions at the national and grid levels. The proposed methodology is based on external-input-based downscaling for population, convergence-based downscaling for GDP and emissions, and linear algorithms to go to grid levels. The algorithms are applied to the IPCC-SRES scenarios, where the results seem to provide a credible basis for global environmental change assessments.     

Climate change and the transition to neoliberal environmental governance

What are the guiding principles of contemporary international governance of climate change and to what extent do they represent neoliberal forms? We document five main political and institutional shifts within the UN Framework Convention on Climate Change (UNFCCC) and outline core governance practices for each phase. In discussing the current phase since the Paris Agreement, we offer to the emerging literature on international neoliberal environmental governance an analytical framework by which the extent of international neoliberal governance can be assessed. We conceptualize international neoliberal environmentalism as characterized by four main processes: the prominence of libertarian ideals of justice, in which justice is defined as the rational pursuit of sovereign self-interest between unequal parties; marketization, in which market mechanisms, private sector engagement and purportedly ‘objective’ considerations are viewed as the most effective and efficient forms of governance; governance by disclosure, in which the primary obstacles to sustainability are understood as ‘imperfect information’ and onerous regulatory structures that inhibit innovation; and exclusivity, in which multilateral decision-making is shifted from consensus to minilateralism. Against this framework, we argue that the contemporary UNFCCC regime has institutionalized neoliberal reforms in climate governance, although not without resistance, in a configuration which is starkly different than that of earlier eras. We conclude by describing four crucial gaps left by this transition, which include the ability of the regime to drive adequate ambition, and gaps in transparency, equity and representation.     

Precaution and proportionality in the management of global environmental change

The precautionary principle is a mandate to tread cautiously when managing novel threats to the environment or human health. A major obstacle when applying the principle at the international level is disagreement about how precautionary efforts should be constrained to ensure that policy costs are proportional to the attained level of protection. Proportionality is an unresolved question when preliminary evidence precludes decision-makers from assigning probabilities over future events. The paper suggests practical analytical tools for communicating ex ante trade-offs when probabilities are unavailable. The tools could be used to facilitate discussion and compromise when implementing precautionary decisions in international settings where cooperation is important. The approach is demonstrated in an application to climate policy that uses the integrated assessment model DICE (Nordhaus, 2008). The paper also situates the task of precautionary decision-making within the broader context of implementing a precautionary response at the international level.     

Calibration and use of a sailplane variometer to measure vertical velocity fluctuations

The calibration of a sailplane variometer to measure vertical velocity fluctuations in the atmospheric boundary layer is described. Its usefulness is demonstrated with typical results from a boundary-layer development study. The atmospheric calibrations gave the ratio of standard deviations of vertical velocity fluctuations measured by a standard tower-mounted turbulence instrument to the values measured by variometer as 2.5 m s^–1 V^–1.     

The forgotten casualties: women, children, and environmental change.

The author posits that women and children bear a disproportionate burden of environmental degradation and are in the worst position to mitigate the consequences of deteriorating environmental conditions. This article discusses the concept of environmental equity or fairness and its sociospatial impacts and the different adjustments made by women and children. Environmental equity is both an outcome and a process. Process equity includes the underlying causes of uneven distributions of resources. The 1992 Rio Declaration on Environment and Development defines 27 specific principles that broadly follow three forms of equity: social equity, generational equity, and procedural equity. Social equity is defined as the role of social, economic, and political forces in resource consumption and environmental degradation. Environmental risk is related to locational criteria such as cheap land and transportation access and by the social geography of places. Hazardous waste dumping is used to illustrate inequitable waste disposal in developing countries such as Brazil, Mexico, Nigeria, Lebanon, Syria, Venezuela, Zimbabwe, and South Korea. Generational equity is defined as fairness over time. The issue of permanent radioactive waste disposal is a current issue that has implications for future generations. Three strategies are important in assuring generational equity: the maintenance of natural and cultural diversity; a reduction in environmental degradation; and the provision of equal access to resources. Preservation of parkland is a positive strategy and lack of access to health services and reproductive health care is a negative strategy. Procedural equity is defined as the extent to which regulations are applied fairly. The example is given of higher fines for dumping waste in "nice White communities" compared to minority ones. Environmental law regulating hazardous waste exports has been minimally effective. Women and children are affected by particulate pollution and environmental toxins (lead and pesticides) in the air and water of urban areas and by a composite of poverty, development, and urbanization.     

The use of scenarios as the basis for combined assessment of climate change mitigation and adaptation

Scenarios are used to explore the consequences of different adaptation and mitigation strategies under uncertainty. In this paper, two scenarios are used to explore developments with (1) no mitigation leading to an increase of global mean temperature of 4 °C by 2100 and (2) an ambitious mitigation strategy leading to 2 °C increase by 2100. For the second scenario, uncertainties in the climate system imply that a global mean temperature increase of 3 °C or more cannot be ruled out. Our analysis shows that, in many cases, adaptation and mitigation are not trade-offs but supplements. For example, the number of people exposed to increased water resource stress due to climate change can be substantially reduced in the mitigation scenario, but adaptation will still be required for the remaining large numbers of people exposed to increased stress. Another example is sea level rise, for which, from a global and purely monetary perspective, adaptation (up to 2100) seems more effective than mitigation. From the perspective of poorer and small island countries, however, stringent mitigation is necessary to keep risks at manageable levels. For agriculture, only a scenario based on a combination of adaptation and mitigation is able to avoid serious climate change impacts.     

Climate variability and change within the discharge time series: a statistical approach

The paper contains some results of long-time series analysis of discharges with respect to climate variability and change. The appropriate statistical computations based on data supplied by the Global Runoff Data Center in Koblenz. The computations have been carried out for the case of annual and of monthly (of each month) time series. The verification of the assumed hypotheses has been conducted for 5% significance level.The hypothesis that the mean value and the variance are stationary and ergodic (Kruskal-Wallis test) have to be rejected, respectively: (a) from 10.2% to 21.6% of cases and from 1.7% to 7.4% of cases for monthly discharges; and (b) in 23.3% and 3.4% of cases for annual discharges. Whereas, in case of the Mann-Kendall test trends emerge (a) in the mean value from 25% of cases to 42.6% of cases, and in the variance from 10.2% of cases to 19.3% of cases for monthly discharges; (b) in 42% and 9.1% of cases there occur trends in the mean value and the variance, respectively, for annual discharges. Moreover, results of the tests are presented separately for the time series being independently and dependently distributed in time.     

Settlement abandonment in the context of global environmental change

This article reports findings from a study of settlement abandonment and the interactions between environmental and non-environmental factors that may give rise to it. Through a modified systematic review of scholarly literature, an inventory of 246 ancient and modern examples of settlement abandonment was generated. Common spatial and temporal parameters were identified and a typology created to summarize environmental and non-environmental drivers common across cases. Dynamic interactions of drivers that lead to a progression from vulnerability to population decline and abandonment were examined in the cases of Plymouth, Montserrat, abandoned due to volcanism in the 1990s; recent rural depopulation in northeastern Iraq and the southern marshes; outmigration from the southern Aral Sea region; and, neighbourhood abandonment and a proposal to convert abandoned lands in Detroit to commercial farming. The study finds that with growing vulnerability to environmental change across many regions, there is greater potential for increased numbers of abandonments. However, abandonment should be seen as only one possible outcome of environment and population interactions that create vulnerability and stimulate environmental migration. The study concludes with a series of observations relevant to anticipating and planning for potential population decline and settlement abandonment in the face of future global environmental change.     

Impacts of climate change as a function of global mean temperature: maize productivity and water use in China

Projections of future climate change are plagued with uncertainties from global climate models and emission scenarios, causing difficulties for impact assessments and for planners taking decisions on adaptation measure. Here, we developed an approach to deal with the uncertainties and to project the changes of maize productivity and water use in China using a process-based crop model, against a global mean temperature (GMT) increase scale relative to 1961?C1990 values. From 20 climate scenarios output from the Intergovernmental Panel on Climate Change Data Distribution Centre, we adopted the median values of projected changes in monthly mean climate variables for representative stations and driven the CERES-Maize model to simulate maize production under baseline and future climate scenarios. Adaptation options such as automatic planting, automatic application of irrigation and fertilization were considered, although cultivars were assumed constant over the baseline and future. After assessing representative stations across China, we projected changes in maize yield, growing period, evapotranspiration, and irrigation-water use for GMT changes of 1°C, 2°C, and 3°C, respectively. Results indicated that median values of projected decreases in the yields of irrigated maize without (with) consideration of CO₂-fertilization effects ranged from 1.4% to 10.9% (1.6% to 7.8%), 9.8% to 21.7% (10.2% to 16.4%), and 4.3% to 32.1% (3.9% to 26.6%) for GMT changes of 1°C, 2°C, and 3°C, respectively. Median values of projected changes in irrigation-water use without (with) consideration of CO₂-fertilization effects ranged from ?1.3% to 2.5% (?18.8% to 0.0%), ?43.6% to 2.4% (?56.1% to ?18.9%), and ?19.6% to 2.2% (?50.6% to ?34.3%), which were ascribed to rising CO₂ concentration, increased precipitation, as well as reduced growing period with GMT increasing. For rainfed maize, median values of projected changes in yields without (with) consideration of CO₂-fertilization effects ranged from ?22.2% to ?1.0% (?10.8% to 0.7%), ?27.6% to ?7.9% (?18.1% to ?5.6%), and ?33.7% to ?4.6% (?25.9% to ?1.6%). Approximate comparisons showed that projected maize yield losses were larger than previous estimates, particularly for rainfed maize. Our study presents an approach to project maize productivity and water use with GMT increases using process-based crop models and multiple climate scenarios. The resultant impact function is fundamental for identifying which climate change level is dangerous for food security.     

气候变化对环境与健康影响研究进展

气候变化对环境与健康的影响日益受到关注。分析了气候变化对大气环境、水环境和土壤环境的胁迫效应,阐述了气候变化对生态系统和人体健康的影响,并概述了气候变化对不同介质环境以及对生态系统与人体健康影响研究的进展。这一工作可以为今后气象与环境领域开展进一步研究提供基本框架。     

East African food security as influenced by future climate change and land use change at local to regional scales

Climate change impacts food production systems, particularly in locations with large, vulnerable populations. Elevated greenhouse gases (GHG), as well as land cover/land use change (LCLUC), can influence regional climate dynamics. Biophysical factors such as topography, soil type, and seasonal rainfall can strongly affect crop yields. We used a regional climate model derived from the Regional Atmospheric Modeling System (RAMS) to compare the effects of projected future GHG and future LCLUC on spatial variability of crop yields in East Africa. Crop yields were estimated with a process-based simulation model. The results suggest that: (1) GHG-influenced and LCLUC-influenced yield changes are highly heterogeneous across this region; (2) LCLUC effects are significant drivers of yield change; and (3) high spatial variability in yield is indicated for several key agricultural sub-regions of East Africa. Food production risk when considered at the household scale is largely dependent on the occurrence of extremes, so mean yield in some cases may be an incomplete predictor of risk. The broad range of projected crop yields reflects enormous variability in key parameters that underlie regional food security; hence, donor institutions’ strategies and investments might benefit from considering the spatial distribution around mean impacts for a given region. Ultimately, global assessments of food security risk would benefit from including regional and local assessments of climate impacts on food production. This may be less of a consideration in other regions. This study supports the concept that LCLUC is a first-order factor in assessing food production risk.