粮食安全:气候变化与粮食产地转移

基于1985-2008年中国雀际面板数据,实证检验了气候变化对粮食种植规模与单位产量的作用机制,进而分析了产地转移对国家粮食总供给的影响.结论表明:①中国的稻谷、小麦、玉米产业正分别向黑龙江、河南、内蒙古等气候资源匮乏地区转移或集聚;②粮食产地转移的主导因素在于粮食作物与经济作物、种植业与畜牧业、农业与非农的成本收益比较,而气候变化因素仅处于附属地位;③基于规模效应、牧入效应以及回弹效应的作用机制,东北三省、河南、内蒙古等地区的增长潜质往往优于其他地区;④落后地区应对气候变化的生产与政策成本,往往要低于发达地区保留粮食生产的机会成本,粮食生产向欠发达地区转移应具有可持久性.粮食产地转移过程中,并未呈现粮食供给安全的“个体理性”与“集体理性”的冲突.中国应该在气象预报、水利设施、抗灾能力、中低产田改造等方面加大投入,摒弃区内平衡的传统观念,在全国范围内优化资源配置,并辅以国家粮食储备战略应对特大灾害的供给风险.     

Exploring the efficiency of bias corrections of regional climate model output for the assessment of future crop yields in Europe

Excessive summer drying and reduced growing season length are expected to reduce European crop yields in future. This may be partly compensated by adapted crop management, increased CO₂ concentration and technological development. For food security, changes in regional to continental crop yield variability may be more important than changes in mean yields. The assessment of changes in regional and larger scale crop variability requires high resolution and spatially consistent future weather, matching a specific climate scenario. Such data could be derived from regional climate models (RCMs), which provide changes in weather patterns. In general, RCM output is heavily biased with respect to observations. Due to the strong nonlinear relation between meteorological input and crop yields, the application of this biased output may result in large biases in the simulated crop yield changes. The use of RCM output only makes sense after sufficient bias correction. This study explores how RCM output can be bias corrected for the assessment of changes in European and subregional scale crop yield variability due to climate change. For this, output of the RCM RACMO of the Royal Netherlands Meteorological Institute was bias corrected and applied within the crop simulation model WOrld FOod STudies to simulate potential and water limited yields of three divergent crops: winter wheat, maize and sugar beets. The bias correction appeared necessary to successfully reproduce the mean yields as simulated with observational data. It also substantially improved the year-to-year variability of seasonal precipitation and radiation within RACMO, but some bias in the interannual variability remained. This is caused by the fact that the applied correction focuses on mean and daily variability. The interannual variability of growing season length, and as a consequence the potential yields too, appeared even deteriorated. Projected decrease in mean crop yields is well in line with earlier studies. No significant change in crop yield variability was found. Yet, only one RCM is analysed in this study, and it is recommended to extend this study with more climate models and a slightly adjusted bias correction taking into account the variability of larger time scales as well.     

Recent patterns of production for the main cereal grains: implications for food security in China

China’s large population and deteriorating environment have created great concern related to the sustainability of food production, especially since details related to this topic remain poorly studied. Thus, an integrated analysis of both crop yield and cultivated area is essential for gaining a better understanding of cereal grain production in China and for making corresponding policies designed to achieve food security. In this study, we adopt trend analysis of both provincial yield and cultivated area to assess the subsequent provincial-level cereal production sustainability between 1980 and 2011 with the goal of providing a better understanding of regional agricultural development. The results indicate that while maize shows the most promise for yield improvement, rice and wheat production is experiencing substantial yield stagnation among most provinces across mainland China. In addition, the trends in spatial patterns are prominently different from those of yields. The sizes of the main rice- and wheat-growing areas in China have declined greatly, suggesting that the related production of these cereals should attract more attention from land management planners and farmers. Specifically, the south-eastern coastal provinces have largely failed to sustain both crop yield and area, while the north-eastern provinces have witnessed thriving agricultural production during the last three decades. Moreover, we find that cereal production in China is significantly affected by governmental policies related to the agricultural sector. Thus, this analysis of food production in China will help policymakers to better understand how the potential implications of food security in China may be applicable to countries worldwide.     

中国未来的粮食安全与生态可持续性问题研究——基于粮食生产过程生态足迹的实证分析

自然资源与农业生态可持续开发是保障农业生产与粮食安全可持续发展的基础。随着我国人口的增长以及人们生活水平的提高,粮食需求量逐年增加。这不但加剧了我国人多地少的矛盾,还给我国农业资源与生态的可持续发展带来了挑战。利用计量模型测算出我国人口高峰时粮食安全背景下粮食生产活动的生态足迹,然后依据生态足迹指数法判断其生态可持续性状况。结果显示,按照目前的粮食生产模式依靠自给实现粮食安全,我国人均生态足迹指数将出现负值。这意味着我国农业生态将处于不可持续的状态。解决我国“粮食 耕地”矛盾与“粮食 生态”矛盾,实现粮食安全与农业生态的协调可持续发展,一方面需要把我国目前依靠要素投入的粗放式粮食生产模式转向生态友好型的种植模式;另一方面需要改变我国依靠自给的粮食安全保障模式,通过适当降低我国的粮食自给率、增加粮食进口缓解我国农业资源与生态环境的压力。这对我国未来的农业发展道路以及粮食安全政策都具有重要的参考价值     

Acid sulfate soils and human health—A Millennium Ecosystem Assessment

Acid sulfate soils have been described as the “nastiest soils on earth” because of their strong acidity, increased mobility of potentially toxic elements and limited bioavailability of nutrients. They only cover a small area of the world's total problem soils, but often have significant adverse effects on agriculture, aquaculture and the environment on a local scale. Their location often coincides with high population density areas along the coasts of many developing countries. As a result, their negative impacts on ecosystems can have serious implications to those least equipped for coping with the low crop yields and reduced water quality that can result from acid sulfate soil disturbance. The Millennium Ecosystem Assessment called on by the United Nations in 2000 emphasised the importance of ecosystems for human health and well-being. These include the service they provide as sources of food and water, through the control of pollution and disease, as well as for the cultural services ecosystems provide. While the problems related to agriculture, aquaculture and the environment have been the focus of many acid sulfate soil management efforts, the connection to human health has largely been ignored. This paper presents the potential health issues of acid sulfate soils, in relation to the ecosystem services identified in the Millennium Ecosystem Assessment. It is recognised that significant implications on food security and livelihood can result, as well as on community cohesiveness and the spread of vector-borne disease. However, the connection between these outcomes and acid sulfate soils is often not obvious and it is therefore argued that the impact of such soils on human well-being needs to be recognised in order to raise awareness among the public and decision makers, to in turn facilitate proper management and avoid potential human ill-health.     

Erratum to: Addressing future trade-offs between biodiversity and cropland expansion to improve food security

Potential trade-offs between providing sufficient food for a growing human population in the future and sustaining ecosystems and their services are driven by various biophysical and socio-economic parameters at different scales. In this study, we investigate these trade-offs by using a three-step interdisciplinary approach. We examine (1) how the expected global cropland expansion might affect food security in terms of agricultural production and prices, (2) where natural conditions are suitable for cropland expansion under changing climate conditions, and (3) whether this potential conversion to cropland would affect areas of high biodiversity value or conservation importance. Our results show that on the one hand, allowing the expansion of cropland generally results in an improved food security not only in regions where crop production rises, but also in net importing countries such as India and China. On the other hand, the estimated cropland expansion could take place in many highly biodiverse regions, pointing out the need for spatially detailed and context-specific assessments to understand the possible outcomes of different food security strategies. Our multidisciplinary approach is relevant with respect to the Sustainable Development Goals for implementing and enforcing sustainable pathways for increasing agricultural production, and ensuring food security while conserving biodiversity and ecosystem services.

     

建设我国节水高效农业的战略对策

21世纪我国水资源供需矛盾进一步加剧,农用水资源严重短缺,解决我国粮食安全问题,必须发展节水高效农业,本文阐述了未来我国农业可持续发展面临的节水任务,分析了影响节水发展的制约因素,提出了促进节水高效农业发展的战略措施和对策。     

Policies for Livestock Development in the Ethiopian Highlands

Since 1991, there have been significant changes in utilization of feed resources in the Ethiopian highlands: while use of communal grazing lands and private pastures has declined, use of crop residues and purchased feed has increased. In addition, although use of animal health services and adoption of improved livestock breeds and modern management practices have increased, ownership of various types of livestock has declined. Rapid population growth has contributed most to the declining trends in grazing resources and ownership of livestock, showing the negative effects of increasing pressure on already degraded resources in the Ethiopian highlands. Land redistribution, increased participation in credit and extension programs targeting livestock, and improvement in access to markets, on the other hand, have had significant positive impacts on adoption of improved livestock technologies and ownership of livestock. Thus, reducing population growth and improving access to markets and credit and extension programs targeting livestock can enhance the role of livestock in improving food security and reducing poverty, especially in the mixed crop-livestock farming systems as exist in the East African highlands.     

Climate change and food security: a Sri Lankan perspective

There is growing concern in Sri Lanka over the impact of climate change, variability and extreme weather events on food production, food security and livelihoods. The link between climate change and food security has been mostly explored in relation to impacts on crop production or food availability aspects of food security, with little focus on other key dimensions, namely food access and food utilization. This review, based on available literature, adopted a food system approach to gain a wider perspective on food security issues in Sri Lanka. It points to several climate-induced issues posing challenges for food security. These issues include declining agriculture productivity, food loss along supply chains, low livelihood resilience of the rural poor and prevalence of high levels of undernourishment and child malnutrition. Our review suggests that achieving food security necessitates action beyond building climate resilient food production systems to a holistic approach that is able to ensure climate resilience of the entire food system while addressing nutritional concerns arising from impacts of climate change. Therefore, there is a pressing need to work towards a climate-smart agriculture system that will address all dimensions of food security. With the exception of productivity of a few crop species, our review demonstrates the dearth of research into climate change impacts on Sri Lanka’s food system. Further research is required to understand how changes in climate may affect other components of the food system including productivity of a wider range of food crops, livestock and fisheries, and shed light on the causal pathways of climate-induced nutritional insecurity.     

Assessment of the impacts of climate change and variability on water resources and use,food security,and economic welfare in Iran

Climate change influences the agricultural sector by reducing available water resources, thereby influencing income, consumer and producer surplus, and crop prices. So, it is necessary to have a comprehensive integrated method to measure the effects of these changes on natural resources and social conditions. The present study aims to use the positive mathematical programming method to discover the trend and conditions of groundwater resources, agricultural water use, food security, and economic welfare of the agricultural sector in Iran. To this end, data for the period 2000–2015 was used under four different scenarios of normal climate change, climate change, climate variability, and concurrent climate change The results showed that the mean agricultural water use will amount to 35,103.6, 26,533.8, 35,216, and 26,510.7 million m³ and the mean decline in the reserves of aquifers will amount to 4422.22, 11,165.6, 4438.25, and 11,267.4 million m³ under the scenarios, respectively. With respect to food security, the net farm revenue will be 314,560, 248,753, 315,427, and 248,574 billion IRR, respectively. The mean crop price per ton will reach 905.3, 1141.8, 904, and 1142.8 million IRR, respectively. The mean consumer surplus will be 172,107.7, 166,450, 172,024, and 166,403 billion IRR and the mean producer surplus will be 419,959.2, 395,380, 419,751, and 395,204 billion IRR, respectively. Based on the results, to reduce the adverse impacts of climate change on different studied aspects, it is necessary to change policymaking in the water and agricultural sectors, especially regarding the shift from traditional agricultural water allocation to its market-based allocation and to change planting pattern.

     

Urban Agriculture：A Transitional Mechanism for Reducing Environmental Degradation and Fossil Fuel over Dependence

With the increasing population in the urban cities of the world,the demand for food from distant areas has been on the rise but at the expense of scarce natural resources like oil,water and forest,etc.However,producing food locally in urban centers provides a sustainable mechanism of reducing the carbon,food or ecological footprints of these cities in particular and environmental degradation in general.It creates a circular metabolic system in which the natural inputs are efficiently harnessed rather than the linear metabolic system in which resources flow in and wastes flow out.This article analyzes some urban agricultural local initiatives in urban centers of the worlds that promote a circular metabolic systems and proposes the procedure that can be adopted to promote urban agriculture.     

Implications of climate change in sustained agricultural productivity in South Asia

One of the targets of the United Nations ‘Millennium Development Goals’ adopted in 2000 is to cut in half the number of people who are suffering from hunger between 1990 and 2015. However, crop yield growth has slowed down in much of the world because of declining investments in agricultural research, irrigation, and rural infrastructure and increasing water scarcity. New challenges to food security are posed by accelerated climatic change. Considerable uncertainties remain as to when, where and how climate change will affect agricultural production. Even less is known about how climate change might influence other aspects that determine food security, such as accessibility of food for various societal groups and the stability of food supply. This paper presents the likely impacts of thermal and hydrological stresses as a consequence of projected climate change in the future potential agriculture productivity in South Asia based on the crop simulation studies with a view to identify critical climate thresholds for sustained food productivity in the region. The study suggests that, on an aggregate level, there might not be a significant impact of global warming on food production of South Asia in the short term (<2°C; until 2020s), provided water for irrigation is available and agricultural pests could be kept under control. The increasing frequency of droughts and floods would, however, continue to seriously disrupt food supplies on year to year basis. In long term (2050s and beyond), productivity of Kharif crops would decline due to increased climate variability and pest incidence and virulence. Production of Rabi crops is likely to be more seriously threatened in response to 2°C warming. The net cereal production in South Asia is projected to decline at least between 4 and 10% under the most conservative climate change projections (a regional warming of 3°C) by the end of this century. In terms of the reference to UNFCCC Article 2 on dangerous anthropogenic (human-induced) interference with the climate system, the critical threshold for sustained food productivity in South Asia appears to be a rise in surface air temperature of ~2°C and a marginal decline in water availability for irrigation or decrease in rainfall during the cropping season.     

Can Sustainable Agriculture Feed Africa? New Evidence on Progress, Processes and Impacts

Africa faces enormous food security challenges. Most commentators agree that, despite the complexities of food insecurity, there will have to be increases in food production from existing agricultural land. Most, too, are pessimistic about the future, judging likelihood of success on the basis of past performance of modern agricultural development. Sustainable agriculture, though, offers new opportunities, by emphasising the productive values of natural, social and human capital, all assets that Africa either has in abundance or that can be regenerated at low financial cost.This paper sets out an assets-based model of agricultural systems, together with a typology of eight improvements that are currently in use in sustainable agriculture projects. In the 45 projects/initiatives spread across 17 countries that are investigated, some 730,000 households have substantially improved food production and household food security. In 95% of the projects where yield increases were the aim, cereal yields have improved by 50–100%. Total farm food production has increased in all. The additional positive impacts on natural, social and human capital are also helping to build the assets base so as to sustain these improvements in the future.This analysis indicates that sustainable agriculture can deliver large increases in food production in Africa. But spreading these to much larger numbers of farm households will not be easy. It will require substantial policy, institutional and professional reform.     

根据承载力确定土地资源安全度

土地资源安全维系着国民经济的可持续发展，而可持续发展是在不超过生态系统承载力情况下的一种安全发展模式。因此，通过土地资源承载力分析，可以了解土地资源的安全度。由于人类种群的增长可用Logstic模型[SX(]DN[]dt[SX)]=r·N·[JB(（][SX(]\{K-N\}[]K[SX)][JB)）]加以描述。运用熵理论推导证明[SX(]K[]2[SX)]≤N<[JB（(]1+[SX(]1[][KF(]3[KF)][SX)][JB))]·[SX(]K[]2[SX)]为模型的全局解，可作为区域土地资源的人口安全区间。以江苏省为例，在确定人口承载力的基础上，分别给出了温饱型、小康型和富裕型等三种生活水平下的土地资源安全评价标准。结果表明：目前江苏省土地资源在三种生活水平下均处于安全状况，但在富裕生活水平下人口已接近安全上限，必须控制人口，保护土地资源;提出进一步研究土地资源安全度应解决的几个问题。     

Impacts of soil and water pollution on food safety and health risks in China

Environmental pollution and food safety are two of the most important issues of our time. Soil and water pollution, in particular, have historically impacted on food safety which represents an important threat to human health. Nowhere has that situation been more complex and challenging than in China, where a combination of pollution and an increasing food safety risk have affected a large part of the population. Water scarcity, pesticide over-application, and chemical pollutants are considered to be the most important factors impacting on food safety in China. Inadequate quantity and quality of surface water resources in China have led to the long-term use of waste-water irrigation to fulfill the water requirements for agricultural production. In some regions this has caused serious agricultural land and food pollution, especially for heavy metals. It is important, therefore, that issues threatening food safety such as combined pesticide residues and heavy metal pollution are addressed to reduce risks to human health. The increasing negative effects on food safety from water and soil pollution have put more people at risk of carcinogenic diseases, potentially contributing to ‘cancer villages’ which appear to correlate strongly with the main food producing areas. Currently in China, food safety policies are not integrated with soil and water pollution management policies. Here, a comprehensive map of both soil and water pollution threats to food safety in China is presented and integrated policies addressing soil and water pollution for achieving food safety are suggested to provide a holistic approach.     

Establish the Long-effective Mechanism of Food Security in China

Abstract

In despite of fluctuation in recent years, the grain yield in China has been increasing, which relieves the conflict between supply and demand and turns the situation of food security good. However, because of the rapid increase in food consumption, the conflicts of food quality and structure in the supply and demand equilibrium has become more and more obvious and the long-effective mechanism of food security has not been established yet. It is found that the factors affecting food security in China include the scarcity and dissipation of resources, farmers’ low enthusiasm in planting grain crops and the inappropriateness of the emphasis and measures of macro-economic regulation and control. Therefore, the authors advance to optimize resources allocation, strengthen macro-economic regulation and control and policy stimulation and establish the mechanism of allocating grain production cost, to set up the long-effective mechanism of China food security and keep it stable in the long term.     

Linking agricultural adaptation strategies,food security and vulnerability: evidence from West Africa

Adaptation strategies to reduce smallholder farmers’ vulnerability to climate variability and seasonality are needed given the frequency of extreme weather events predicted to increase during the next decades in sub-Saharan Africa, particularly in West Africa. We explored the linkages between selected agricultural adaptation strategies (crop diversity, soil and water conservation, trees on farm, small ruminants, improved crop varieties, fertilizers), food security, farm household characteristics and farm productivity in three contrasting agro-ecological sites in West Africa (Burkina Faso, Ghana and Senegal). Differences in land area per capita and land productivity largely explained the variation in food security across sites. Based on land size and market orientation, four household types were distinguished (subsistence, diversified, extensive, intensified), with contrasting levels of food security and agricultural adaptation strategies. Income increased steadily with land size, and both income and land productivity increased with degree of market orientation. The adoption of agricultural adaptation strategies was widespread, although the intensity of practice varied across household types. Adaptation strategies improve the food security status of some households, but not all. Some strategies had a significant positive impact on land productivity, while others reduced vulnerability resulting in a more stable cash flow throughout the year. Our results show that for different household types, different adaptation strategies may be ‘climate-smart’. The typology developed in this study gives a good entry point to analyse which practices should be targeted to which type of smallholder farmers, and quantifies the effect of adaptation options on household food security. Subsequently, it will be crucial to empower farmers to access, test and modify these adaptation options, if they were to achieve higher levels of food security.     

Climate change,food stress,and security in Russia

Farming in higher latitudes is generally believed to benefit from a warmer climate due to extended growing season, reduced risk of frost, availability of more productive cultivars, and an opening potential of farming in northern locations. We analyzed the impact of climate change on production of cereals in Russia and found that this general perception of beneficiary effect of a warmer climate is unlikely to hold, primarily due to increasing risk of droughts in the most important agricultural areas of the country. Past impacts of droughts on food security throughout the twentieth century suggest that a number of adaptation options are available to mitigate the increasing risks of crop failure. We analyze the effectiveness of these measures in connection with a set of climate change projections, under two contrasting scenarios of interregional grain trade: “Fortress Market” and “Open Market.”     

横断山区干旱河谷大气水资源变化特征与演变趋势研究

利用横断山区干旱河谷内24个气象站逐月降水、气温等观测资料,依托高桥浩一郎陆面蒸发公式,计算了干旱河谷区陆面蒸发、可利用降水等水资源分量,并分析了各分量的未来演变趋势。结果表明:干旱河谷区年均降水量723.7mm,而年均蒸发量高达479.5mm,降水量中有超过84.89%因蒸发而损耗;大气水资源分量P、E及PE季节变化非常明显,夏季各分量最大,多年平均值达404.9mm、239.9mm和164.8mm,各占全年的55.94%、50.04%和67.51%,而冬季各分量最小,占全年的比例也相应最小,仅为2.96%、4.06%和0.79%;大气水资源各分量年代际差异很大,20世纪60年代可利用水资源丰富,70年代相对偏少,80和90年代逐渐增加,进入21世纪后又呈现为偏少特征;未来干旱河谷区的降水量维持减少的概率较转向增加的概率要小,蒸发量将依然维持增加的趋势,而可利用水资源量会继续维持减少的倾向。     

全面放开二孩政策背景下人口增长对资源环境的影响和需求分析

2015年底,我国全面放开了二孩政策,势必对我国的人口总量和增长态势产生深刻影响,进而影响我国的资源需求和环境压力。在采用队列元素法预测全面放开二孩后我国总人口及各省(市、自治区)人口的基础上,运用城乡人口比增长法预测未来城镇化水平,本文依据这两种预测结果系统探讨人口政策变动对我国资源消费、环境污染的定量预测和具体影响。假定未来的人均资源环境消耗量保持现状不变,按照预测的未来人口总量和增量,得出人口增长对我国资源环境的需求变动。通过计算新增的资源环境需求量,对比需求总量与我国的资源环境供给能力,进一步分析人口增长对资源环境各方面的压力大小。研究发现:全面放开二孩政策后,我国的粮食、生活用能源、生活用水、城乡建设用地的需求量和生活污染物排放量均逐年递增,但变化速率有所差异。为满足未来人口增长所产生的需求,粮食和能源的自给率明显降低,未来将需要更多地依赖进口。全国的供水能力和保障水平急需提高,其中北京、河南、江苏、青海、四川的现状供水能力与未来生活用水需求差距较大。各省建设用地需求差异明显,吉林、湖北、山东、四川、江苏、湖南、新疆、广东、黑龙江、贵州等省市的城市建设用地新增需求量将快速释放,但已有的建设用地储备无法满足预测需求。生活污染物的治理压力加大,环境保护与治理能力应该继续加强。