关键词： Albedo   CO2   Greenhouse gas   Methane   Nitrous oxide   Radiative forcing  

摘要： Land-use change between forestry and agriculture can cause large net emissions of carbon dioxide (CO2), and the respective land uses associated with forest and pasture lead to different on-going emission rates of methane (CH4) and nitrous oxide (N2O) and different surface albedo. Here, we quantify the overall net radiative forcing and consequent temperature change from specified land-use changes. These different radiative agents cause radiative forcing of different magnitudes and with different time profiles. Carbon emission can be very high when forests are cleared. Upon reforestation, the former carbon stocks can be regained, but the rate of carbon sequestration is much slower than the rate of carbon loss from deforestation. A production forest may undergo repeated harvest and regrowth cycles, each involving periods of C emission and release. Agricultural land, especially grazed pastures, have much higher N2O emissions than forests because of their generally higher nitrogen status that can be further enhanced through intensification of the nitrogen cycle by animal excreta. Because of its longevity in the atmosphere, N2O concentrations build up nearly linearly over many decades. CH4 emissions can be very high from ruminant animals grazing on pastures. Because of its short atmospheric longevity, the CH4 concentration from a converted pasture accumulates for only a few decades before reaching a new equilibrium when emission of newly produced CH4 is balanced by the oxidation of previously emitted CH4. Albedo changes generally have the opposite radiative forcing from those of the GHGs and partly negate their radiative forcing. Overall and averaged over 100 years, CO2 is typically responsible for 50% of radiative forcing and CH4 and N2O for 25% each. Albedo changes can negate the radiative forcing by the three greenhouse gases by 20-25%. (C) 2013 Elsevier B.V. All rights reserved.

关键词： 农业   气候变化   适应政策  

摘要： 气候变化是21世纪全球面临的严重挑战之一,农业是最易遭受气候变化影响的产业。通过对欧盟、美国及澳大利亚在农业领域对气候变化适应政策的研究分析,提出对中国农业适应气候变化的启示。

关键词： 气候变化   农业开发   人类活动   全球气候变暖   大气组成   臭氧层破坏   痕量气体   地球气候  

摘要： 气候变化是指在自然气候变化之外由人类活动直接或间接地改变全球大气组成所导致的气候改变。气候变化主要表现为：全球气候变暧，酸雨、臭氧层破坏三方面，其中全球气候变暖是人类目前面临的最迫切的问题，关乎到人类的未来。对地球气候有重大影响的是大气中的许多痕量气体如：

关键词： Climate change   Environmental impact   Agriculture  

摘要： The impact of climate change on US agriculture has been debated for more than two decades, but the estimates ranged from no damage at the lower end to 80 % losses of grain yields at the higher end. This essay aims to help understand such divergent predictions by clarifying the concepts of weather and climate. First, the widely-read panel fixed effects models capture only the impacts of weather fluctuations but not of climate normals. Random weather fluctuations and climatic shifts are two different meteorological events and they have distinct implications on farming decisions. The former is perceived as random while the latter is perceived as non-random by the farmers. Using the historical corn yield data in the US, I explain the differences between the impact of random weather and that of climate change. Second, adaptation strategies to climatic changes and increased climate risks cannot be accounted for by the panel fixed effects models. Using the farm household data collected in sub-Saharan Africa and Latin America, I discuss quantitative significance of modeling adaptation strategies in the estimates of climate damage. Distinction between random weather fluctuations and climatic shifts is critical in modeling farming decisions, as they are fundamental to climate science, but is poorly understood by the impact researchers.

关键词： Land-use changes   Climate change   Biodiversity indicators   Birds   Agricultural policy  

摘要： The use of forward scenarios to forecast the environmental implications of potential changes in climate and land use is a useful tool for policy development. In this paper, we projected the potential responses of bird communities to both climate and agricultural changes. We created four scenarios of agricultural changes (current trends, biofuel development, livestock extensification and agricultural extensification), each developed at national or regional level of policy-making. We further considered three climatic scenarios (A1B, A2 and B1) from among the IPCC 4th Assessment Report scenarios. We assessed changes in bird communities based on the predicted changes in agricultural land use and climatic suitability using various indicators, including the European Farmland Bird Indicator (FBI) and the Community Specialisation Index (CSI). We found that trends in the different indicators differed greatly from each other depending on the agricultural scenarios and policy-making scale. Our results suggest that public policies that promote extensive agricultural practices are more appropriate for improving the fate of bird communities in agricultural landscapes, especially with the regionalisation of agricultural policy. These results provide a readily accessible visualisation of the potential impacts of land use and climate change on farmland bird communities. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： 农业主体   气候变化   经济分析  

摘要： 气候变化给农业带来巨大风险,研究农业主体应对气候变化的作用机理对于指导农业生产实践具有重要的应用价值。该文基于新古典经济学的研究范式,首先,应用数理模型研究直接从事农业生产的农户如何通过改变生产要素投入适应气候变化的机理;其次,应用成本-效益方法,分析政府选择适应气候变化的措施和政策的标准;进而,构建一个农业适应气候变化的经济理论模型,揭示农业主体适应气候变化的机理,从而为实践中适应气候变化提供理论基础。

关键词： 低碳农业   应对气候变化   绵阳市  

摘要： 气候变化是当今人类社会共同面临的最大的环境问题,而在气候变化的维度上,农业是一把双刃剑,它既有碳排放功能又有固碳功能,对全球温室气体排放起着十分关键的作用。因此,发展低碳农业成为低碳经济时代的必然要求。绵阳市是一个科技资源相对丰富但能源资源较为贫乏的地区,因而发展低碳农业是应对气候变化下,绵阳市践行十八大提出的"绿色、循环、低碳"发展精神、建设"美丽绵阳"的现实选择。

关键词： 气候   农业生产   评估  

摘要： 本文总结出了杜尔伯特县1960-2009年气候的变化特征,根据气候变化的具体情况研究对农业生产、生态环境等产生的影响及应采取的对策。

关键词： Irrigation   Mekong Delta   Water quantity   Water quality   Wastewater treatment   Rice crop  

摘要： Climate change is impacting water resources in the Mekong Delta of Vietnam. Drought is becoming more severe and water scarcer. Thus, action on adaptation to climate impacts is urgently needed. We assess the potential for wastewater reuse as an adaptation measure to cope with water scarcity in Can Tho City, within the heart of the Mekong Delta. We show that wastewater effluent can be used to irrigate at least to 22,719 ha of paddy rice (16% of the rice-cultivated area in the city) at 3 crops per year. The fertilizing properties of the water would eliminate part of the demand for synthetic fertilizers, providing a maximum of 22% of the nitrogen (N) and 14% of the phosphorus (P) requirement for the winter-spring crop. On a yearly basis, recovery of wastewater could reduce the discharge of N by 15-27% and the discharge of P by 8-17%. Such a program would contribute to a decrease in the level of pollution in the local rivers and canal systems, while also reducing the need for expensive tertiary treatment (C) 2013 Elsevier B.V. All rights reserved.

关键词： CLIMATIC changes -- Economic aspects   CLIMATIC changes -- Risk assessment   CLIMATIC changes -- Social aspects   WINE industry   COFFEE industry  

摘要： The article reports on the effects of climate change on the two agricultural crops such as wine and coffee. Topics discussed include the weather conditions that provoke adaptations in wine grapes, the vulnerability of coffee growers, and the study of scientist Juliana Jaramillo on coffee agriculture in Nairobi, Kenya. Researcher Tim Schilling of World Coffee Research also mentioned that their research programs are done for the improvement of the livelihoods of the producer and their welfare.