关键词： Population growth   Food production   Dynamic global vegetation model   Climate change   LPJmL  

摘要： The human population is projected to reach more than 10 billion in the year 2100. Together with changing consumption pattern, population growth will lead to increasing food demand. The question arises whether or not the Earth is capable of fulfilling this demand. In this study, we approach this question by estimating the carrying capacity of current agricultural systems (K-C), which does not measure the maximum number of people the Earth is likely to feed in the future, but rather allows for an indirect assessment of the increases in agricultural productivity required to meet demands. We project agricultural food production under progressing climate change using the state-of-the-art dynamic global vegetation model LPJmL, and input data of 3 climate models. For 1990 to 2100 the worldwide annual caloric yield of the most important 11 crop types is simulated. Model runs with and without elevated atmospheric CO2 concentrations are performed in order to investigate CO2 fertilization effects. Country-specific per-capita caloric demands fixed at current levels and changing demands based on future GDP projections are considered to assess the role of future dietary shifts. Our results indicate that current population projections may considerably exceed the maximum number of people that can be fed globally if climate change is not accompanied by significant changes in land use, agricultural efficiencies and/or consumption pathways. We estimate the gap between projected population size and K-C to reach 2 to 6.8 billion people by 2100. We also present possible caloric self-supply changes between 2000 and 2100 for all countries included in this study. The results show that predominantly developing countries in tropical and subtropical regions will experience vast decreases of self-supply. Therefore, this study is important for planning future large-scale agricultural management, as well as the critical assessment of population projections, which should take food-mediated climate

关键词： Climate change   Water balance   Agricultural suitability  

摘要： The productive characteristics and agricultural potential of a region are strongly related to its climate conditions, and these have changed in an unprecedented way worldwide in the last 70 years. While the warming since the late nineteenth century has been established as between 0.3 and 0.6 degrees C, the variation of other climatic elements such as precipitation, cloudiness and evaporation, has been much less explored. Climate change and variability in the central region of Argentina between 1941 and 2010 was studied, with special emphasis on water balance information, and the impact on agricultural suitability was assessed both temporally and spatially. Time series of 7 successive decades of climatic and agroclimatic variables expressed spatially were used, with Sen's nonparametric tests to assess the rate of change, and Mann-Kendall's to establish the significance of the trend. While no major change was seen in the annual values of potential evapotranspiration (ETP), with significant rates that were positive in only 6% and negative in 2% of the territory, 57% of the territory presents an increasing total annual rainfall trend, which significantly reduced aridity. There is a general downward trend in water deficiency (Del), so that this indicator of aridity and productivity has negative rates over time (P < 0.10) in 25% of the territory, with a mean value of -33 mm decade(-1). The Moisture Index (IH) trend is positive in 99% and significantly positive in 42% of the region, marking wetter atmospheric conditions, especially up to the late twentieth century. Change in agricultural suitability was assessed by determining the variation of agroclimatic indicators of soybean crops at 4 sites in the production area. The results are spatially heterogeneous, with barely noticeable thermal and hydrological changes in Marcos Juarez, showing its more stable agroclimatic aptitude, but more apparent changes in Ceres and Laboulaye. While water deficit explains the low agricultur

关键词： 全球气候变化   粮食生产   农业生产   极端气候事件   自然要素   作物生长   经济发展   社会系统  

摘要： 农业尤其是粮食生产是以作物生长为基础，直接依赖于水、热、土等自然要素，对气候变化非常敏感。我国是一个人口大国，经济发展迅速，生活水平不断提高，需要确保国内粮食等大宗农产品稳定供给。粮食生产涉及的因素很多，是一个非常复杂的自然-社会系统。气候变化直接影响农业和粮食的生产，由于全球气候的变化，常导致极端气候事件频发，严重影响农业生产。

关键词： SWAT   Great Lakes   Flow   Sediments   Catchment   Lake Erie  

摘要： Agricultural best management practices (BMPs) have been implemented in the watersheds around Lake Erie to reduce nutrient transfer from terrestrial to aquatic ecosystems and thus protect and improve the water quality of Lake Erie. However, climate change may alter the effectiveness of these BMPs by altering runoff and other conditions. Using the Soil and Water Assessment Tool (SWAT), we simulated various climate scenarios with a range of BMPs to assess possible changes in water, sediment, and nutrient yields from four agricultural Lake Erie watersheds. Tile drain flow is expected to increase as is the amount of sediment that washes from land into streams. Predicted increases in tributary water flow (up to 17%), sediment yields (up to 32%), and nutrient yields (up to 23%) indicate a stronger influence of climate on sediment compared to other properties. Our simulations found much greater yield increases associated with scenarios of more pronounced climate change, indicating that above some threshold climate change may markedly accelerate sediment and nutrient export. Our results indicate that agricultural BMPs become more necessary but less effective under future climates;nonetheless, higher BMP implementation rates still could substantially offset anticipated increases in sediment and nutrient yields. Individual watersheds differ in their responsiveness to future climate scenarios, indicating the importance of targeting specific management strategies for individual watersheds. (C) 2014 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved.

关键词： Baltic Sea   SWAT   Agriculture   Climate change   Adaptation measures   Scenario  

摘要： Currently, there is a major concern about the future of nutrient loads discharged into the Baltic Sea from Polish rivers because they are main contributors to its eutrophication. To date, no watershed-scale studies have properly addressed this issue. This paper fills this gap by using a scenario-modeling framework applied in the Reda watershed, a small (482 km(2)) agricultural coastal area in northern Poland. We used the SWAT model to quantify the effects of future climate, land cover, and management changes under multiple scenarios up to the 2050s. The combined effect of climate and land use change on N-NO3 and P-PO4 loads is an increase by 20-60 and 24-31 %, respectively, depending on the intensity of future agricultural usage. Using a scenario that assumes a major shift toward a more intensive agriculture following the Danish model would bring significantly higher crop yields but cause a great deterioration of water quality. Using vegetative cover in winter and spring (VC) would be a very efficient way to reduce future P-PO4 loads so that they are lower than levels observed at present. However, even the best combination of measures (VC, buffer zones, reduced fertilization, and constructed wetlands) would not help to remediate heavily increased N-NO3 loads due to climate change and agricultural intensification.

关键词： Climate change   density dependence   human activity   population dynamic   time series   variation partitioning  

摘要： Understanding drivers of population fluctuation, especially for agricultural pests, is central to the provision of agro-ecosystem services. Here, we examine the role of endogenous density dependence and exogenous factors of climate and human activity in regulating the 37-year population dynamics of an important agricultural insect pest, the cotton bollworm (Helicoverpa armigera), in North China from 1975 to 2011. Quantitative time-series analysis provided strong evidence explaining long-term population dynamics of the cotton bollworm and its driving factors. Rising temperature and declining rainfall exacerbated the effect of agricultural intensification on continuously weakening the negative density dependence in regulating the population dynamics of cotton bollworms. Consequently, ongoing climate change and agricultural intensification unleashed the tightly regulated pest population and triggered the regional outbreak of H. armigera in 1992. Although the negative density dependence can effectively regulate the population change rate to fluctuate around zero at stable equilibrium levels before and after outbreak in the 1992, the population equilibrium jumped to a higher density level with apparently larger amplitudes after the outbreak. The results highlight the possibility for exogenous factors to induce pest outbreaks and alter the population regulating mechanism of negative density dependence and, thus, the stable equilibrium of the pest population, often to a higher level, posing considerable risks to the provision of agro-ecosystem services and regional food security. Efficient and timely measures of pest management in the era of Anthropocene should target the strengthening and revival of weakening density dependence caused by climate change and human activities.

关键词： 河北地区   气候变化   农业影响  

摘要： 以气温和降水为主要气候因子,选取河北及京津23个气象站点数据,分析河北地区1956-2007年气候变化特征:近50年全区年均气温呈波动上升趋势,且冬季气温升高对年气温的上升贡献率最大;年降水量总体呈波动减少趋势,其中夏季降水呈明显波动减少趋势。对未来该区气候变化特征进行了预估。从地下水位、土地环境、农业病虫害的角度分析了河北地区气候变化对农业生产环境的影响;分析了近50年来气候变化对农作物种植制度的影响以及对作物生理生态和品质产生的不确定影响。气候变化在一定程度上降低了农业生产水平,提高了生产成本,频发的极端气候事件也会增加农业生产的损失。最后给出了未来气候变化对该区农业的可能影响。

关键词： IPCC第二工作组   第五次评估报告   气候变化   农业生产   粮食安全  

摘要： IPCC第二工作组在第五次评估报告中客观而审慎地评估了气候变化已经发生和潜在的影响、各个领域与区域的敏感性和脆弱性。针对农业生产与粮食安全,报告表明,气候变化对全球大部分地区作物、畜牧、渔业产生了影响,且负面影响更普遍;不仅影响到生产过程,也影响到非生产系统因素,但这些影响存在区域差异。极端事件(如极端高温)对作物产量、品质及市场价格的负面影响明显。大气中CO_2浓度增高有利于作物产量提高,但是与温度、臭氧以及水分利用、病虫草害等协同效应仍然不明确。增强适应可以克服增温对农业的负面影响,并减少粮食损失。关于气候变化对粮食安全非生产系统因素的影响及如何开展适应,还需要搜集更多的证据。

关键词： 气候变化   综合评估   多指标   农业   弱性   中国   云南省  

摘要： 2014年7月29日，ClimaticChange在线发表的题为《用多指标方法综合评估中国农业的气候变化脆弱性》（IntegratedAssessmentofChina’s AgriculturalVulnerabilitytoClimateChange：aMulti-indicatorApproach）的文章表明，中国贵州、广西和云南省的农业对气候变化尤为脆弱，并且到2040年，这些地区的农业气候变化脆弱性还将进一步恶化。

关键词： Europe   Drought   Climate variability   Geographic information systems (GIS)   Agriculture   Communications/decision making  

摘要： This research focuses on the adaptability of olive-growing systems to climate change in the Sierra Magina region of Andalusia. The authors combined a retrospective and prospective analysis, an interdisciplinary approach, collaboration among climatologists, geographers, and sociologists, and the participation of local farmers and stakeholders, all contributing their own knowledge. This paper assesses the adaptability of olive-growing systems to climate irregularities over the past 50 yr. First, a climatic study shows that rainfall decreased by 18% during the period 1955-2009. Water resource availability has declined 2 or 3 times more than rainfall, in part because of the expansion of irrigation, which ameliorated the effects of droughts and increased profitability. Second, relationships between rainfall and both irrigated and rainfed olive yields are assessed. These show that the cumulative rainfall of the 2 yr preceding the crop explains 41% of the variability of irrigated olive tree yields and 46% of rainfed yields;this result was unexpected for irrigated yields. Third, this study examines the perceptions of climate variability of 15 farmers, the views of 16 local stakeholders [developers, olive oil professionals, local authorities, a conservationist, and a representative of a local nongovernmental organization (NGO)]. The perceptions of the farmers are interpreted with respect to their socioeconomic status. All farmer and stakeholder interviewees know to a certain extent the climatic influence on olive yields, and most of them acknowledge the recent climatic changes. These findings will be valuable for future assessments of the adaptability of the agricultural and social systems to climate change.