关键词： adaptation   agriculture   climate change   maladaptation   nitrogen   political economy  

摘要： In this article, we explore if and why farmers are responding to the impacts of climate change with practices that increase greenhouse gas emissions. Our examination focuses on heavy rainfall events and Midwestern corn farmers' nitrogen fertilizer management. Due to climate change, the frequency and intensity of heavy rain events is increasing across the Midwest. These events increase nitrogen loss to the environment and introduces economic risks to farmers. Drawing from a theoretical framework that merges O'Connor's second contradiction of capitalism and Schnaiberg's treadmill of production, we argue farmers' responses to these events reflect the second contradiction, increasing contributions to climate change, and are shaped by treadmill-like political-economic pressures. We examine this using a qualitative sample of 154 farmers across Indiana, Iowa, and Michigan. Given profit imperatives, adapting farmers in our sample primarily used increased nitrogen application rates to reduce their vulnerability to heavy rains. As nitrogen rate is directly associated with nitrous oxide emissions, this adaptive strategy is effective but increases agricultural contributions to climate change. This preliminarily suggests that the political-economic structure encourages farmers to respond to climate change in ways that accelerate the environmental contradictions of industrial agriculture.

关键词： Tree ring   Vegetation coverage   Climate change   Agricultural cultivation   Northwest China  

摘要： Comprehending the characteristics and causes of vegetation coverage in history is of practical significance for studying ecological and environmental changes. As a typical region of the semi-arid and semi-humid climatic zone in northwest China, the upper reaches of the Weihe River have relatively fragile ecological environment. Based on tree-ring width chronologies, the vegetation coverage represented by the normalized difference vegetation index was reconstructed from 1630 to 2006 using a regression model. There were 64 years with high vegetation coverage and 56 years with low vegetation coverage over the past 377 years. At low frequencies, the coverage was relatively higher in the 1650s and from the 1880s to 1890s, while the coverage was lower in the 1720s and from the 1760s to 1770s. While precipitation and temperature had positive and negative influences on the changes of vegetation coverage, respectively, during the past several centuries, the agricultural cultivation played an important role on coverage changes. Along with the land reclamation expansion in history, the forest cover gradually declined, and vegetation coverage decreased. The vegetation coverage was lower when there were more arable lands reclaimed from woodlands. Regardless of the land reclamation policy during the historical period or the current conversion project of cropland to forest, they affected the vegetation coverage by influencing cover ranges of woodland and farmland. (C) 2019 Elsevier B.V. All rights reserved.

关键词： 农业开发   气候变化   策略  

摘要： 随着经济和科技的不断发展与进步,我国的农业技术也得到了飞速的发展,但是还存在许多问题,农业开发过程受气候变化的影响比较严重,因此农业开发需要不断适应气候变化,创新农业开发模式,提升农业开发的技术。本文就对农业开发适应气候变化的相关策略进行简要的分析和探讨。

关键词： 气候变化   农户属性   感知   适应行为   路径分析  

摘要： 厘清农户的气候变化适应行为类型以及农户属性、气候变化感知对适应行为的影响机制,对于制定合适的适应政策至关重要。论文将适应行为分为技术性行为、经济性行为和迁移性行为3类,并构建了以气候变化感知为中介变量的“属性-感知-适应”多变量路径分析模型,在对农户属性对适应行为的影响进行多元方差分析的基础上探讨了变量间的影响路径。结果表明:①农户适应气候变化会优先选择技术性行为,其次是经济性行为,选择迁移性行为的农户最少;②农户属性对适应行为的影响具有显著差异;③根据中介变量的中介效应,将多变量路径分析模型分解为3类:完全中介模型、部分中介模型和无中介模型。通过分析以上3种模型可以发现,农户属性对适应行为既有通过中介变量产生的间接影响,也有不通过中介变量产生的直接影响,说明适应行为的选择并不仅仅依赖于气候变化感知,农户属性对于适应行为的选择也是一个重要的直接影响因素。最后针对提高农户应对气候变化的能力提出了相关政策建议。

关键词： 唐代   气候变化   农业   影响  

摘要： 唐朝在我国历史上处于第三个温暖期,气候的总体特征是温暖湿润,但也有出现波动的时候,有一个相对的寒冷期。以八世纪中叶为分界点,气候由暖转寒,而气候变化对社会发展产生的最直接影响表现在农业生产方面,气候的冷暖对农业发展起着促进或者阻碍的作用。本文先略述唐代气候的冷暖变化,从而进一步说明气候变化对唐代农业发展的影响。

关键词： Global climate change   Local yield changes   The Sudan   Climate variability   Interventions  

摘要： Sudan is a country with a predominantly rainfed agriculture which is a major contributor to GDP, foreign exchange earnings, and livelihoods. However, with current and projected environmental changes on the horizon there is an urgent need to measure and analyze the impact of these changes. This study analyzes the economy-wide impacts of climate change and consults national policy plans, strategies, and environmental assessments to identify interventions for mitigating the effects. We feed climate forcing data, projected water demand, and macro-socioeconomic trends into a modeling suite, which includes models for global hydrology, river basin management, water stress, and crop growth. This modeling suite provides us with annual crop yields and global food prices under various climate change scenarios until 2050. The effects from climate change are assessed by using a single country dynamic CGE model for the Sudan. Additionally, we introduce yield variability into the CGE model based on stochastic shocks of crop yields until 2050. The results reveal that extreme negative variability could cost the Sudan cumulatively US$ 105.5 billion in GDP between 2018 and 2050 compared to a baseline scenario without climate change.

关键词： agricultural R&D   climate change adaptation   R&D depreciation   R&D lags   total factor productivity   Q11   Q16   Q54  

摘要： Investments in agricultural research and development (R&D) made over the next few decades will likely prove critical in offsetting adverse climate change impacts on the global food system. In this study, we offer cost estimates of public R&D-led adaptation to climate change grounded in an explicit framework relating the flow of annual R&D expenditures to building knowledge capital and thereby raising productivity in agriculture. Our research uses a comprehensive collection of historical public agricultural R&D expenditure and a literature review of elasticity estimates linking knowledge stocks to agricultural productivity growth for key world regions. Given climate-driven crop yield projections generated from extreme combinations of crop and global circulation models, we find that offsetting crop yield losses projected by climate and crop models over 2006-2050 would require increased R&D adaptation investments of between $187 billion and $1,384 billion (in 2005 $PPP) if we invest between 2020 and 2040. This is 16-118% higher than global R&D investment if present spending trends continue. Although these costs are significant, worldwide R&D-led climate adaptation could offer favorable economic returns. Moreover, R&D-led adaptation could deliver gains in food security and environmental sustainability by mitigating food price increases and slowing cropland expansion.

关键词： Climatic water balance   Precipitation   Reference evapotranspiration   Maize yields   Agricultural impact   Economic impact   Romania  

摘要： The impact of climate change on agricultural systems has become a reality that currently threatens food security in numerous regions worldwide. However, concrete consequences of climate change on agricultural yields still remain unknown in many countries around the world, including Romania. This study conducts a first-ever analysis of the impact of climate change on maize productivity in Romania, the European Union's leader in maize harvested production, which holds almost 30% of the European maize production. The paper explores complex statistical relationships between the climatic water balance (CWB)/its constituting parameters precipitation (P) and reference evapotranspiration (ETo) and maize yields (Zea mays L.) recorded nationally from 1990 to 2013, a key-period in Romania in terms of climate and socio-political changes. The analysis of various agro-climatic data, based on well-established methods (linear regression and bootstrapping), showed that the countrywide dependence of maize yields variability to changes in the analyzed climatic variables was considerable and reached peak values of roughly 60% for the CWB-yield relationship and around 50% for the P-yield and ETo-yield relationships. At the same time, a significant sensitivity of maize yield dynamics was found in response to a 1-unit climate change, which, on average, was quantified at 5 kg/ha/yr for a 1-mm variation of the CWB, and at 19 kg/ha/yr and 11 kg/ha/yr for a 1-mm change in P and ETo, respectively. In addition to this agricultural impact, our findings regarding the economic impact associated to concrete climatic trends (CWB decreases and ETo increases over the 24 years, consistent with an overall increase of the humidity deficit, and P increases, consistent with humidity surplus) indicate total costs of approximately 53 mil (sic) (or almost 1% of the national agricultural gross domestic product) for the CWB-yield relationship, and of similar to 200 mil (sic) (similar to 3%) for ETo-yield. It wa

关键词： Natural insurance   Market insurance   Yield insurance   index insurance   Choice experiments   Latent class   Risk mitigation   Sustainable soil management  

摘要： This paper focuses on the potential use of insurance as a climate change adaptation mechanism in agriculture. We analyse the attractiveness of a climate risk insurance scheme and the choices farmers face between adaptation via farm management practices and purchase of crop insurance in the market. A choice experiment is used to reveal Danish farmers' preferences regarding an insurance contract where adoption of land management practices to improve soil sustainability is conditional for obtaining insurance cover in the market. Results indicate that in general arable farmers and farmers with low soil quality who have experienced crop damages in the past are more likely to purchase such conditional insurance. Farmers with good quality soils, who perceive that they have already adapted their practices to climatic risks and who have not experienced losses due to adverse climatic events in the past are less willing to purchase insurance. The paper contributes to the limited knowledge on preferences for climate risk related insurance in agricultural systems in general, and in Europe in particular.

关键词： Temporal trend   Land use and cover change   Bird communities   Conservation   Landscape dynamics   Long-term monitoring   Farmland   Climate warming  

摘要： Rural landscapes of western Europe have considerably changed in the last decades under the combined pressure of climate and land use changes, leading to a dramatic decline of farmland biodiversity, including common farmland birds. The respective roles of climate and land use and cover changes in driving bird population trends are primarily assessed at national or continental levels. Yet, it is often challenging to integrate their intertwined effects at such large scales due to the lack of data on fine-scale land cover changes. Here, we used a long-term bird monitoring scheme, combined with a land cover survey, conducted during 30 years (1981-2011) across 780 sites in a 20,000 ha study area in south-western France, dominated by low-intensity farming systems. We tested the direct effect of temporal changes in climate and land use on the dynamics of two community-level metrics: the bird Community Thermal Index (CTI) and bird Community Generalization Index (CGI). We used a novel method to assess the contribution of species-specific dynamics to CTI and CGI trends. We observed a significant increase in CTI and a significant decrease in CGI between 1981 and 2011, i.e., bird communities now have higher thermal preferences and are more specialized than 30 years ago. Bird CTI and CGI changes were both related to local climate- and land use-related drivers, especially mean temperature increase and hedgerow loss. Trends in CTI and CGI were primarily driven by the loss of cold-dwelling and generalist species, and secondly by a gain in hot-dwelling specialists. Our long-term study brings new empirical evidence that the effects of climate and land cover changes on bird communities are intrinsically intertwined, and need to be considered together to monitor and predict the future of farmland biodiversity. It also suggests that low-input, diversified agriculture combined with the maintenance of semi-natural habitat cover can contribute to the conservation of both specialist and gene