东江流域1959-2009年气候变化及其对径流的影响

依据东江流域21个气象站1959-2009年逐年平均降雨、蒸发、日照、湿度及气温等气象要素序列,选择常用的线性倾向估计及非参数M．K等趋势分析方法,分析了东江流域近50年来气温、降水、蒸发、日照及湿度等气象要素的变化趋势。选择降雨和蒸发两个气候要素两两组合,构成未来气候变动的36种假想情景,运用改进的SCS月模型模拟计算了顺天流域年径流量的变化幅度。结果表明：在过去的50年间,流域降雨量呈不显著增长,而气温则为显著上升,其他气候要素如蒸发、日照及湿度等均呈不同程度减少趋势;关联度分析表明降雨在所有气象要素中与径流的关联度为最大,说明了在东江流域降雨是径流量变化的主要驱动因子;未来流域降雨增加,蒸发减少的气候情景模式下,径流量会有所增加,反之亦然;由降雨变化引起的流域月径流量的增幅较由蒸发变化引起的相应流量的增幅变化大。     

Crime,weather, and climate change

This paper estimates the impact of climate change on the prevalence of criminal activity in the United States. The analysis is based on a 30-year panel of monthly crime and weather data for 2997 US counties. I identify the effect of weather on monthly crime by using a semi-parametric bin estimator and controlling for state-by-month and county-by-year fixed effects. The results show that temperature has a strong positive effect on criminal behavior, with little evidence of lagged impacts. Between 2010 and 2099, climate change will cause an additional 22,000 murders, 180,000 cases of rape, 1.2 million aggravated assaults, 2.3 million simple assaults, 260,000 robberies, 1.3 million burglaries, 2.2 million cases of larceny, and 580,000 cases of vehicle theft in the United States.     

Exploring the future of European crop production in a liberalised market, with specific consideration of climate change and the regional competitiveness

Long-term future development of European agriculture within the global market is highly uncertain, but can potentially have large impacts on the future of agricultural businesses, rural communities and amenities such as traditional landscapes and biodiversity. Despite great uncertainties it is of interest to explore the extent of these potential changes. This paper provides an explorative scenario of the European crop production in a liberalised world without European Union (EU) market interventions. The results do not form a prediction or a business as usual scenario, but rather a plausible and salient thought-experiment of a possible future based on the consistent integration of current conceptual and quantitative models.Future scenarios for climate, demography, technology and global demand for agricultural commodities are used to assess the competitiveness of European agriculture. Regional economic competitiveness is determined by combining indicators for the economic strength of farms in a region and population pressure on agricultural land, and subsequently used to determine where agricultural production is likely to sustain under the market liberalisation scenario. The method is illustrated for the 27 EU member state countries for three commodities: wheat, potato and milk (relying on grass).Results include maps of the dominant wheat, potato and milk producing regions across Europe as projected for 2050. They show that due to increased agricultural productivity, less agricultural land will be needed to supply the European demand for food and feed. In addition, production will concentrate in those regions which have a comparative advantage. This potentially leads to a strong polarisation between north-western Europe and southern Europe, which faces negative impacts of climate change and central and northern Europe where agricultural businesses lag in economic strength and farm size. A contrasting policy intervention scenario illustrates how differences in demand and productivity result in an expansion of the agricultural area, especially for the production of wheat.Although the complete liberalisation scenario may seem unlikely, and the underlying assumptions have great uncertainty, the results help identify and map market pressures on agricultural land use across regions in Europe. As such, it stimulates policy debate on the desired future for the European agricultural sector and the trade-offs between economic competitiveness under global market conditions and policy intervention. In addition, it provides a basis for the planning of alternative economic strategies for agriculturally less competitive regions.     

Effects of experience and weather on foraging rate and pollen versus nectar collection in the bumblebee, Bombus terrestris

This study examines factors that affect foraging rate of free-flying bumblebees, Bombus terrestris, when collecting nectar, and also what factors determine whether they collect pollen or nectar. We show that nectar foraging rate (mass gathered per unit time) is positively correlated with worker size, in accordance with previous studies. It has been suggested that the greater foraging rate of large bees is due to their higher thermoregulatory capacity in cool conditions, but our data suggest that this is not so. Workers differing in size were not differentially affected by the weather. Regardless of size, naïve bees were poor foragers, often using more resources than they gathered. Foraging rate was not maximised until at least 30 trips had been made from the nest. Foraging rates were positively correlated with humidity, perhaps because nectar secretion rates were higher or evaporation of nectar lower at high humidity. Temperature, wind speed and cloud cover did not significantly influence foraging rate, within the summertime range that occurred during the study. Weather greatly influenced whether bees collected pollen or nectar. Pollen was preferably collected when it was warm, windy, and particularly when humidity was low; and preferably during the middle of the day. We suggest that bees collect pollen in dry conditions, and avoid collecting pollen when there is dew or rain-water droplets on the vegetation, which would make grooming pollen into the corbiculae difficult. Availability of sufficient dry days for pollen collection may be an important factor determining the success of bumblebee colonies.Communicated by M. Giurfa     

Climate treaties and approaching catastrophes

If the threshold that triggers climate catastrophe is known with certainty, and the benefits of avoiding catastrophe are high relative to the costs, treaties can easily coordinate countries' behavior so as to avoid the threshold. Where the net benefits of avoiding catastrophe are lower, treaties typically fail to help countries cooperate to avoid catastrophe, sustaining only modest cuts in emissions. These results are unaffected by uncertainty about the impact of catastrophe. By contrast, uncertainty about the catastrophic threshold normally causes coordination to collapse. Whether the probability density function has “thin” or “fat” tails makes little difference.     

近50年青海省气候变化特征及其与ENSO的关系

厄尔尼诺-南方涛动(ENSO)常引起大气环流的改变并导致气候的异常变动。研究区域气候变化与ENSO之间的相互关系,有助于了解区域水文等各要素的变化。文章基于1960—2010年青海省29个气象站点的降水、气温数据与表征ENSO的热带太平洋海表温度距平(SSTA)和南方涛动指数(SOI)资料,通过气候倾向率、Mann-Kendall突变检验、相关性检验和小波分析等方法,研究了1960—2010年青海省降水和气温的变化特征及其与ENSO的关系。结果表明,1960—2010年青海省气候趋向暖湿,且这种趋势在90年代后愈加显著。在整个时间段内,气候变化尤其是降水变化与ENSO有显著的关系。在ENSO的冷暖事件时间段内,青海省的降水与气温都与海表温度、南方涛动指数有显著的相关性。由小波分析得出,降水和气温可能都受海表温度的影响较大;ENSO事件对青海省气温变化的影响大于对青海降水的影响。     

Adjustment costs from environmental change

The paper is concerned with the case whereby the distribution of a firm's productivity shocks changes without the knowledge of the firm. Over time the firm learns about the nature and extent of the change in the distribution of the shock and adjusts, incurring adjustment costs in the process. The long-run loss in profits (±) due to the shift in the distribution we term the equilibrium response. The transitory loss in profits, incurred while the firm is learning about the distribution shift, is termed the adjustment cost. The theory is then applied to the problem of measuring adjustment costs in the face of imperfectly observed climate change in agriculture. The empirical part of the paper involves estimating a restricted profit function for agricultural land in a five-state region of the Midwest US as a function of prices, land characteristics, actual weather realizations and expected weather. We then simulate the effect of an unobserved climate shock, where learning about the climate shock is by observing the weather and updating prior knowledge using Bayes Rule. We find adjustment costs to climate change are 1.4% of annual land rents.     

Impacts of climate change/variability on the streamflow in the Yellow River Basin, China

Changes of streamflow reflect combined effects of climate, soil and vegetation in the basin scale. This study was conducted to investigate the response of streamflow to the climate changes/variability in different scales of the Yellow River Basin (YRB). The spatial distribution and temporal trends were explored for precipitation and potential evapotranspiration (PE) during 1961-2000 to illustrate climate change/variability and impacts of climate change/variability on streamflow were explained by investigating the relationship of precipitation, PE and streamflow in the YRB. The results presented that: (i) precipitation and PE exhibited different spatial distribution patterns and temporal trends in different regions, and most stations showed negative trends for precipitation in the basin; (ii) the relationship of streamflow with precipitation and PE showed high nonlinearity, and the magnitudes and patterns of streamflow response to precipitation and PE displayed different patterns varied with the dry conditions in different region or years; and (iii) the precipitation elasticity of streamflow (?_P) was 1.80, 1.08, 1.78 and 1.95 in Lanzhou, Toudaoguai, Huayuankou and Lijin respectively, while the PE elasticity of streamflow (?_ET) was −3.41, −4.40, −4.52 and −4.20 in above four scales, respectively, from which can be seen that streamflow was more sensitive to precipitation in wet region than in arid region and inversely it was more sensitive to PE in arid regions than in wet regions. Furthermore, precipitation elasticity of streamflow calculated from the partial correlation presented a reasonable result to show the combined effect of precipitation and PE on streamflow.     

Climate and international trade policies when emissions affect production possibilities

In this paper, we develop a model of international trade and climate change in which emission discharges arising from production have a feedback effect on national production sectors by impacting upon effective factor endowments. With this context, the objectives are, first, to provide a general characterization of Pareto-efficient climate and trade policies and, second, to examine the possibility – starting from non-Pareto-efficient equilibria – for Pareto-improving environmental policies. We provide conditions under which several particular reforms of carbon taxes are welfare improving.     

Evaluating and managing wildlife impacts of climate change under uncertainty

Wildlife managers face the daunting task of managing wildlife in light of uncertainty about the nature and extent of future climate change and variability and its potential adverse impacts on wildlife. A conceptual framework is developed for managing wildlife under such uncertainty. The framework uses fuzzy logic to test hypotheses about the extent of the wildlife impacts of past climate change and variability, and fuzzy multiple attribute evaluation to determine best compensatory management actions for adaptively managing the potential adverse impacts of future climate change and variability on wildlife. A compensatory management action is one that can offset some of the potential adverse impacts of climate change and variability on wildlife. Implementation of the proposed framework requires wildlife managers to: (1) select climate impact states, hypotheses about climate impact states, possible management actions for alleviating adverse wildlife impacts of climate change and variability, and future climate change scenarios; (2) choose biological attributes or indicators of species integrity; (3) adjust those attributes for changes in non-climatic variables; (4) define linguistic variables and associated triangular fuzzy numbers for rating both the acceptability of biological conditions under alternative management actions and the relative importance of biological attributes; (5) select minimum or maximum acceptable levels of the attributes and reliability levels for chance constraints on the biological attributes; and (6) define fuzzy sets on the extent of species integrity and biological conditions and select a fuzzy relation between species integrity and biological conditions. A constructed example is used to illustrate a hypothetical application of the framework by a wildlife management team. An overall best compensatory management action across all climate change scenarios is determined using the minimax regret criterion, which is appropriate when the management team cannot assign or is unwilling to assign probabilities to the future climate change scenarios. Application of the framework can be simplified and expedited by incorporating it in a web-based, interactive, decision support tool.     

Trends in Sex Ratios of Turtles in the United States: Implications of Road Mortality

Abstract:  Road mortality has been implicated as a significant demographic force in turtles, particularly for females, which are killed disproportionately on overland nesting movements. Moreover, the United States' road network has expanded dramatically over the last century. We therefore predicted that historical trends in sex ratios of turtle populations would be male biased. To test this prediction, we synthesized published estimates of population-level sex ratios in freshwater and terrestrial turtles in the United States (165 estimates for 36 species, published 1928–2003). Our analysis suggests that the proportion of males in populations has increased linearly ( p = 0.001); the trend in male bias is synchronized with the expansion of the surfaced portion of the road network since 1930; sex ratios became more male biased in states with higher densities of roads; and populations have become more male biased in aquatic species, in which movement differentials between males and females are greatest, and are least biased in semiaquatic and terrestrial species, in which overland movements are more comparable between sexes. Our results suggest an ongoing depletion of breeding females from wild turtle populations over the last century because of many factors, including, and perhaps chiefly, road mortality.     

Cost-effective environmental policy: implications of induced technological change

Cost-effective environmental policy generally requires that all emission sources are faced with the same tax. In this paper I discuss how the existence of induced technological change may alter this result, if at least some of the effect is external to the firm. Focusing on Learning by doing (LBD) effects in abatement activities, it is shown that emission sources with external learning effects should be faced with a higher tax than emission sources with only autonomous technological change. By using simple numerical simulations, it is further investigated to what degree a cost-effective climate policy differs from a free quota market, under various assumptions about learning effects, diffusion of technology and environmental targets. The results indicate that optimal taxes may be significantly higher in the industrial world than in the developing world. Moreover, the industrial world's share of global abatement may be much higher in a cost-effective solution than in a free quota market. The global cost savings of a fully flexible implementation of the Kyoto Protocol are further questioned, as potential spillover effects of technological growth in the industrial world are not internalised in the market.     

Landuse experience does qualify for adaptation to climate change

The need to implement sustainable resource management regimes for semi-arid and arid rangelands is acute as non-adapted grazing strategies lead to irreversible environmental problems such as desertification and associated loss of economic support to society. In these sensitive ecosystems, traditional sectoral, disciplinary approaches will not work to attain sustainability: achieving a collective vision of how to attain sustainability requires interactive efforts among disciplines in a more integrated approach.     

Land‐Cover Change and Avian Diversity in the Conterminous United States

Abstract: Changes in land use and land cover have affected and will continue to affect biological diversity worldwide. Yet, understanding the spatially extensive effects of land‐cover change has been challenging because data that are consistent over space and time are lacking. We used the U.S. National Land Cover Dataset Land Cover Change Retrofit Product and North American Breeding Bird Survey data to examine land‐cover change and its associations with diversity of birds with principally terrestrial life cycles (landbirds) in the conterminous United States. We used mixed‐effects models and model selection to rank associations by ecoregion. Land cover in 3.22% of the area considered in our analyses changed from 1992 to 2001, and changes in species richness and abundance of birds were strongly associated with land‐cover changes. Changes in species richness and abundance were primarily associated with changes in nondominant types of land cover, yet in many ecoregions different types of land cover were associated with species richness than were associated with abundance. Conversion of natural land cover to anthropogenic land cover was more strongly associated with changes in bird species richness and abundance than persistence of natural land cover in nearly all ecoregions and different covariates were most strongly associated with species richness than with abundance in 11 of 17 ecoregions. Loss of grassland and shrubland affected bird species richness and abundance in forested ecoregions. Loss of wetland was associated with bird abundance in forested ecoregions. Our findings highlight the value of understanding changes in nondominant land cover types and their association with bird diversity in the United States.     

Uncertainty analysis of climate change mitigation options in the forestry sector using a generic carbon budget model

Industrialized countries agreed on a reduction of greenhouse gas emissions under the Kyoto Protocol. Many countries elected forest management activities and the resulting net balance of carbon emissions and removals of non-CO₂ greenhouse gases by forest management in their climate change mitigation measures. In this paper a generic dynamic forestry model (FORMICA) is presented. It has an empirical basis. Several modules trace C pools relevant for the Kyoto Protocol and beyond: biomass, litter, deadwood and soil, and harvested wood products. The model also accounts for the substitution of fossil fuels by wood products and bioenergy.     

Discounting,inequality and economic convergence

The aim of this paper is to examine the impact of inequalities and economic convergence on the efficient discount rate when international credit and risk-sharing markets are inefficient. We consider an economy in which initial consumption levels and growth expectations are heterogeneous. In the benchmark case in which relative inequalities are permanent and relative risk aversion is constant, inequalities do not affect the discount rate. We derive necessary and sufficient conditions under which permanent inequalities reduce the discount rate. We also show that the anticipation of economic convergence raises the efficient discount rate when relative prudence is larger than unity.