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1.
Estimates of impact of climate change on crop production could be biased depending upon the uncertainties in climate change scenarios, region of study, crop models used for impact assessment and the level of management. This study reports the results of a study where the impact of various climate change scenarios has been assessed on grain yields of irrigated rice with two popular crop simulation models- Ceres-Rice and ORYZA1N at different levels of N management. The results showed that the direct effect of climate change on rice crops in different agroclimatic regions in India would always be positive irrespective of the various uncertainties. Rice yields increased between 1.0 and 16.8% in pessimistic scenarios of climate change depending upon the level of management and model used. These increases were between 3.5 and 33.8% in optimistic scenarios. At current as well as improved level of management, southern and western parts of India which currently have relatively lower temperatures compared to northern and eastern regions, are likely to show greater sensitivity in rice yields under climate change. The response to climate change is small at low N management compared to optimal management. The magnitude of this impact can be biased upto 32% depending on the uncertainty in climate change scenario, level of management and crop model used. These conclusions are highly dependent on the specific thresholds of phenology and photosynthesis to change in temperature used in the models. Caution is needed in using the impact assessment results made with the average simulated grain yields and mean changes in climatic parameters.  相似文献   

2.
与IPCC第五次评估报告相比,第六次评估报告（AR6）有关农业的评估对象由作物生产系统延伸到粮食供应链系统,气候变化对作物生产不利影响的证据在加强。气候变化改变了作物适宜种植区,使中高纬度及温带地区作物种植界限向高纬度、高海拔地区推移。人为引起的气候变暖阻碍了作物产量的增长,地表O3浓度增加使作物产量降低,CH4排放加剧了这种不利影响。气候变化加剧作物病虫草害,极端气候事件高发加剧了粮食不安全,推升了国际粮食价格。适应措施有助于减缓气候变化不利影响,基于自然的适应方案在增强作物生产系统气候恢复力和保障粮食安全方面具有较高潜力。从保障国家粮食安全和重大战略需求出发,AR6报告对我国农业应对气候变化相关工作的启示如下：需要高度重视气候变化背景下作物种植适宜区转变与种植带北移的重要战略价值,合理规划农业生产布局;加强农业气象灾害和病虫害防治体系和能力建设,保障粮食生产稳定性;关注气候变化对国际作物生产和谷物贸易的影响,统筹国内、国际市场粮食资源,保障粮食安全;推进农业温室气体减排与作物生产高效协同,为实现国家减排目标做出贡献。  相似文献   

3.
The threat of global climate change has caused concern among scientists because crop production could be severely affected by changes in key climatic variables that could compromise food security both globally and locally. Although it is true that extreme climatic events can severely impact small farmers, available data is just a gross approximation at understanding the heterogeneity of small scale agriculture ignoring the myriad of strategies that thousands of traditional farmers have used and still use to deal with climatic variability. Scientists have now realized that many small farmers cope with and even prepare for climate change, minimizing crop failure through a series of agroecological practices. Observations of agricultural performance after extreme climatic events in the last two decades have revealed that resiliency to climate disasters is closely linked to the high level of on-farm biodiversity, a typical feature of traditional farming systems.Based on this evidence, various experts have suggested that rescuing traditional management systems combined with the use of agroecologically based management strategies may represent the only viable and robust path to increase the productivity, sustainability and resilience of peasant-based agricultural production under predicted climate scenarios. In this paper we explore a number of ways in which three key traditional agroecological strategies (biodiversification, soil management and water harvesting) can be implemented in the design and management of agroecosystems allowing farmers to adopt a strategy that both increases resilience and provides economic benefits, including mitigation of global warming.  相似文献   

4.
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.  相似文献   

5.
IPCC特别报告SRCCL关于气候变化与粮食安全的新认知与启示   总被引：3，自引：0，他引：3  
气候变化对粮食安全的影响是广泛的,不但影响粮食产量和品质,还会影响到农户的生计以及农业相关的产业发展等;而粮食系统在保障粮食安全的同时,又会产生一系列的环境问题,其中农业源温室气体（GHG）的排放加剧全球变暖。IPCC在2019年8月份发布的《气候变化与土地特别报告》（SRCCL）,从粮食生产、加工、储存、运输及消费的各个环节评估气候变化对粮食安全的影响及粮食系统的温室气体排放对气候系统的影响;系统梳理粮食系统供给侧和需求侧的适应与减缓措施、适应与减缓的协同和权衡问题,以及气候变化条件下保障粮食安全的政策环境等。SRCCL评估结论认为,由于大量施用氮肥和消耗水资源,目前粮食系统GHG排放占全球总排放的21%~37%;农业和粮食系统是全球应对气候变化的重要方面,供给侧和需求侧的综合措施可以减少食物浪费、减少GHG排放、增加粮食系统的恢复力。未来工作的重点应丰富和扩展气候变化影响评估内容,量化适应效果,加深对适应、减缓及其协同和权衡的科学认知,大力加强应对气候变化能力建设。  相似文献   

6.
Research on climate change and agriculture has largely focused on production, food prices, and producer incomes. However, societal interest in agriculture is much broader than these issues. The objective of this paper is to analyze the potential impacts of climate change on an important negative externality from agriculture, water quality. We construct a simulation model of maize production in twelve watersheds within the U.S. Chesapeake Bay Region that has economic and watershed components linking climate to productivity, production decisions by maize farmers, and nitrogen loadings delivered to the Chesapeake Bay. Maize is an important crop to study because of its importance to the region's agriculture and because it is a major source of nutrient pollution. The model is run under alternative scenarios regarding the future climate, future baseline (without any climate change), whether farmers respond to climate change, whether there are carbon dioxide (CO2) enrichment effects on maize production, and whether agricultural prices facing the region change due to climate change impacts on global agricultural commodity markets. The simulation results differ from one scenario to another on the magnitude and direction of change in nitrogen deliveries to the Chesapeake Bay. The results are highly sensitive to the choice of future baseline scenario and to whether there are CO2 enrichment effects. The results are also highly sensitive to assumptions about the impact of climate change on commodity prices facing farmers in the Chesapeake Bay region. The results indicate that economic responses by farmers to climate change definitely matter. Assuming that farmers do not respond to changes in temperature, precipitation, and atmosphericCO2 levels could lead to mistaken conclusions about the magnitude and direction of environmental impacts.  相似文献   

7.
Africa is thought to be the region most vulnerable to the impacts of climate variability and change. Agriculture plays a dominant role in supporting rural livelihoods and economic growth over most of Africa. Three aspects of the vulnerability of food crop systems to climate change in Africa are discussed: the assessment of the sensitivity of crops to variability in climate, the adaptive capacity of farmers, and the role of institutions in adapting to climate change. The magnitude of projected impacts of climate change on food crops in Africa varies widely among different studies. These differences arise from the variety of climate and crop models used, and the different techniques used to match the scale of climate model output to that needed by crop models. Most studies show a negative impact of climate change on crop productivity in Africa. Farmers have proved highly adaptable in the past to short- and long-term variations in climate and in their environment. Key to the ability of farmers to adapt to climate variability and change will be access to relevant knowledge and information. It is important that governments put in place institutional and macro-economic conditions that support and facilitate adaptation and resilience to climate change at local, national and transnational level.  相似文献   

8.
Nearly all of Ethiopia’s agriculture is dependent on rainfall, particularly the amount and seasonal occurrence. Future climate change predictions agree that changes in rainfall, temperature, and seasonality will impact Ethiopia with dramatic consequences. When, where, and how these changes will transpire has not been adequately addressed. The objective of our study was to model how projected climate change scenarios will spatially and temporally impact cereal production, a dietary staple for millions of Ethiopians. We used Maxent software fit with crop data collected from household surveys and bioclimatic variables from the WorldClim database to develop spatially explicit models of crop production in Ethiopia. Our results were extrapolated to three climate change projections (i.e., Canadian Centre for Climate Modeling and Analysis, Hadley Centre Coupled Model v3, and Commonwealth Scientific and Industrial Research Organization), each having two emission scenarios. Model evaluations indicated that our results had strong predictability for all four cereal crops with area under the curve values of 0.79, 0.81, 0.79, and 0.83 for teff, maize, sorghum, and barley, respectively. As expected, bioclimatic variables related to rainfall were the greatest predictors for all four cereal crops. All models showed similar decreasing spatial trends in cereal production. In addition, there were geographic shifts in land suitability which need to be accounted for when assessing overall vulnerability to climate change. The ability to adapt to climate change will be critical for Ethiopia’s agricultural system and food security. Spatially explicit models will be vital for developing early warning systems, adaptive strategies, and policy to minimize the negative impacts of climate change on food production.  相似文献   

9.
While previous studies have focused on impacts of average climate change on Russian agriculture and water resources, this study takes into account the impact of changing frequency and spatial heterogeneity of extreme climate events, and the reliance of most of Russia on a few food producing regions. We analyze impacts of the IPCC A2 and B2 climate scenarios with the use of the Global Assessment of Security (GLASS) model (containing the Global Agro-Ecological Zones (GAEZ) crop production model and the Water-Global Assessment and Prognosis (WaterGAP 2) water resources model). As in previous studies we find that decreased crop production in some Russian regions can be compensated by increased production in others resulting in relatively small average changes. However, a different perspective on future risk to agriculture is gained by taking into account a change in frequency of extreme climate events. Under climate normal conditions it is estimated that “food production shortfalls” (a year in which potential production of the most important crops in a region is below 50% of its average climate normal production, taking into account production in food-exporting regions) occur roughly 1–3 years in each decade. This frequency will double in many of the main crop growing areas in the 2020s, and triple in the 2070s. The effects of these shortfalls are likely to propagate throughout Russia because of the higher likelihood of shortfalls occurring in many crop export regions in the same year, and because of the dependence of most Russian regions on food imports from a relatively few main crop growing regions. We estimate that approximately 50 million people currently live in regions that experience one or more shortfalls each decade. This number may grow to 82–139 million in the 2070s. The assessment of climate impacts on water resources indicates an increase in average water availability in Russia, but also a significantly increased frequency of high runoff events in much of central Russia, and more frequent low runoff events in the already dry crop growing regions in the South. These results suggest that the increasing frequency of extreme climate events will pose an increasing threat to the security of Russia's food system and water resources.  相似文献   

10.
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11.
The purpose of this paper is to exemplify a means by which an integrated assessment can be made of global and regional effects on land use of climate change. This is achieved by use of data on the effects of climate change on world food prices as inputs to a regional land use allocation model.Data on world prices are drawn from a recent global study of climate change and crop yields. In a case study of England and Wales a land allocation model is used to infer changes of land use that are the product of the integrated effect of climate-induced global price changes and climate-related changes of yield in England and Wales. This combination of changed prices and yield potential is used to calculate the land use providing the highest returns for each of 155,235 1 km2 cells of land in England and Wales for a future assumed for the year 2060 (without climate change) and then for that same environment with climate change. The difference between these two is then treated as an estimated effect resulting from climate change.  相似文献   

12.
This study estimates the relationship between farm level net-revenue and climate variables in India using cross-sectional evidence. Using the observed reactions of farmers, the study seeks to understand how they have adapted to different climatic conditions across India. District level data is used for the analysis. The study also explores the influence of annual weather and crop prices on the climate response function. The estimated climate response function is used to assess the possible impacts of a ‘best-guess’ climate change scenario on Indian agriculture.  相似文献   

13.
气候变化对中国农业生产影响研究展望   总被引：32，自引：0，他引：32  
综述了气候变化背景下中国农业气候资源、农业气象灾害(干旱、洪涝、高温热浪、低温灾害)和农业病虫害的变化趋势与规律,从农业生产潜力变化、作物种植制度变化和作物品质变化等方面阐明了气候变化对中国农业生产的影响事实,分析了气候变化对中国农业生产的可能影响和中国农业生产适应气候变化的对策措施。在此基础上,针对气候变化背景下中国气候资源的时空分布特点及农业生产出现的新情况、新问题,指出了当前中国关于气候变化对农业影响研究存在的不足,提出了未来气候变化对中国农业生产影响研究需要重视的方面,为确保气候变化背景下中国的农业生产安全及粮食安全提供决策支持。  相似文献   

14.
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15.
Climate change will affect agricultural production by subsistence farms in crop centers of origin, where landraces are conserved in situ. Various strategies for adaptation to climate change have been proposed. In this paper we examine the prospects of what we call the ‘transgenic adaptation strategy’, i.e. the appeal to use transgenic seeds to adapt to climate change, through the lens of smallholder maize farming in Mexico. Landraces are the bedrock of maize production in Mexico. We consider how maize farmers may respond to climate change and the effects of those responses on crop diversity. In this paper, we argue that the promotion of the transgenic adaptation strategy is problematic for biological and social reasons. Smallholder livelihoods in southern Mexico could suffer a disproportionate negative impact if transgenic technology is privileged as a response to climate change. Agroecological and evolutionary approaches to addressing the effects of climate change on smallholder agriculture provides an alternative adaptive strategy.  相似文献   

16.
Long-term field monitoring data and historical crop data are useful to assess the impacts of climate change and to manage cropping systems.The objectives of this study are to understand the cropping system response to a warming-drying trend in the northern agro-pastural ecotone(NAE)of China and to document how farmers can adapt to the warming-drying trend by changing cropping system structure and adjusting planting date.The results indicate that a significant warming-drying trend existed in the NAE from 1980 to 2009,and this trend significantly decreased crop(spring wheat,naked oat,and potato)yields.Furthermore,the yield decreased by 16.2%-28.4%with a 1℃increase in maximum temperature and decreased by 6.6%-11.8%with a 10%decrease in precipitation.Considering food security,water use efficiency,and water ecological adaptability in the semi-arid NAE,cropping system structure adjustment(e.g.,a shift from wheat to potato as the predominant crop)and planting date adaptation(e.g.,a delay in crop planting date)can offset the impact of the warming-drying trend in the NAE.Based on the successful offsetting of the impact of the warming-drying trend in the NAE,we conclude that farmers can reduce the negative effects of climate change and minimize the risk of crop failure by adapting their cropping system structure at the farming level.  相似文献   

17.
This study examines the sensitivity of maize and sorghum crops to global warming in Botswana, a country with arid climatic conditions and shortfalls in locally produced grain. The vulnerability of the maize and sorghum crops to climate change were studied using crop simulation models while climate change scenarios were generated from Global Circulation Models. Simulated yields indicated that rain-fed crop production under the observed climate was a small fraction of what could be produced under optimal conditions. The gap was attributed to both physical (especially lack of rain) and socio-economic constraints. Using the southern African core climate change scenario, simulated yields declined by 36% in the case of maize and 31% for sorghum in the sand veldt region. Yield reductions from thehard veldt region were in the order of 10% for both maize and sorghum. The growing season became shorter, the average reduction in days in the sand veldt region being 5 and 8 days for maize and sorghum respectively, and correspondingly, 3 and 4 days over the hard veldt region. The food security option currently followed in Botswana was found to be a good adaptive strategy under a changed climate.  相似文献   

18.
Climate change will have serious repercussions for agriculture, ecosystems, and farmer livelihoods in Central America. Smallholder farmers are particularly vulnerable due to their reliance on agriculture and ecosystem services for their livelihoods. There is an urgent need to develop national and local adaptation responses to reduce these impacts, yet evidence from historical climate change is fragmentary. Modeling efforts help bridge this gap. Here, we review the past decade of research on agricultural and ecological climate change impact models for Central America. The results of this review provide insights into the expected impacts of climate change and suggest policy actions that can help minimize these impacts. Modeling indicates future climate-driven changes, often declines, in suitability for Central American crops. Declines in suitability for coffee, a central crop in the regional economy, are noteworthy. Ecosystem models suggest that climate-driven changes are likely at low- and high-elevation montane forest transitions. Modeling of vulnerability suggests that smallholders in many parts of the region have one or more vulnerability factors that put them at risk. Initial adaptation policies can be guided by these existing modeling results. At the same time, improved modeling is being developed that will allow policy action specifically targeted to vulnerable groups, crops, and locations. We suggest that more robust modeling of ecological responses to climate change, improved representation of the region in climate models, and simulation of climate influences on crop yields and diseases (especially coffee leaf rust) are key priorities for future research.  相似文献   

19.
Simulating the impacts of climate change on cotton production in India   总被引：1，自引：0，他引：1  
General circulation models (GCMs) project increases in the earth’s surface air temperatures and other climate changes by the mid or late 21st century, and therefore crops such as cotton (Gossypium spp L.) will be grown in a much different environment than today. To understand the implications of climate change on cotton production in India, cotton production to the different scenarios (A2, B2 and A1B) of future climate was simulated using the simulation model Infocrop-cotton. The GCM projections showed a nearly 3.95, 3.20 and 1.85 °C rise in mean temperature of cotton growing regions of India for the A2, B2 and A1B scenarios, respectively. Simulation results using the Infocrop-cotton model indicated that seed cotton yield declined by 477 kg?ha?1 for the A2 scenario and by 268 kg?ha?1 for the B2 scenario; while it was non-significant for the A1B scenario. However, it became non-significant under elevated [CO2] levels across all the scenarios. The yield decline was higher in the northern zone over the southern zone. The impact of climate change on rainfed cotton which covers more than 60 % of the country’s total cotton production area (mostly in the central zone) and is dependent on the monsoons is likely to be minimum, possibly on account of marginal increase in rainfall levels. Results of this assessment suggest that productivity in northern India may marginally decline; while in central and southern India, productivity may either remain the same or increase. At the national level, therefore, cotton production is unlikely to change with climate change. Adaptive measures such as changes in planting time and more responsive cultivars may further boost cotton production in India.  相似文献   

20.
Improving the adaptive capacity of small-scale irrigation systems to the impacts of climate change is crucial for food security in Asia. This study analyzes the capacity of small-scale irrigation systems dependent on the Asian monsoon to adapt to variability in river discharge caused by climate change. Our study is motivated by the Pumpa irrigation system, a small-scale irrigation system located in Nepal that is a model for this type of system. We developed an agent-based model in which we simulated the decisions farmers make about the irrigation strategy to use according to available water flow. Given the uncertainty associated with how climate change may affect the Asian monsoon, we simulated the performance of the system under different projections of climate change in the region (increase and decrease in rainfall, reduction and expansion of the monsoon season, and changes in the timing of the onset of the monsoon). Accordingly to our simulations, farmers might need to adapt to rainfall intensification and a late onset in the monsoon season. The demands for collective action among farmers (e.g. infrastructure repair, meetings, decisions, etc.) might increase considerably due to climate change. Although our model suggests that investment in new infrastructure might increase the performance of the system under some climate change scenarios, the high inequality among farmers when water availability is reduced might hinder the efficiency of these measures due to a reduction of farmers’ willingness to cooperate. Our modeling exercise helps to hypothesize about the most sensitive climate change scenarios for smallscale irrigation farming in Nepal and helps to frame a discussion of some possible solutions and fundamental trade-offs in the process of adaptation to improve for food and water security under climate change.  相似文献   

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