基于缺口率模型的区域粮食安全风险评估

深入分析各区域的粮食供需趋势对于保障中国未来的粮食安全至关重要。该文首先分析了影响中国粮食供需安全的风险源,提出了粮食主产区、粮食主销区和产销平衡区的粮食缺口率风险评估模型并划分了相应的风险等级,然后以洞庭湖区为例进行了实证分析。结果表明:自然灾害是影响洞庭湖区粮食供给安全的最主要因素,人口增长则是影响该区域粮食安全的普遍因素;对于大多数的县/市,资源和投入要素对未来的粮食供给将产生积极的影响。当自然灾害为一般情景或乐观情景时,洞庭湖区的粮食安全状况较为乐观;当自然灾害为悲观情景时,湖区部分县/市的粮食安全形势非常严峻。但就湖区整体而言,通过湖区内部调剂即可以满足高风险县/市的粮食需求。研究结果可为相关部门的政策制定提供客观依据,为粮食安全的风险预警和防范提供参考。

Risk assessment for regional food security based on models of food supply-demand gap

Food security never fails to attract high attention of researchers and policy makers, especially in China, which has more than one fifth of the world's population, but where the total cultivated area accounts for only about seven percent of the world's total cultivated area. However, thus far, relevant studies were normally conducted at the national level, which generally considered China's food security as a whole or used a single set of index system for analysis. Therefore, study on food security from a regional scale will be of great value for policy makers. This paper mainly focuses on the risk sources which can cause food insecurity in China. We proposed a series of supply-demand estimation models to evaluate the gap between supply and demand of food in different areas (food output areas, food import areas and food supply-demand balance areas). Based on different demand-supply gap ratios, the food security risks are categorized into four grades: negligible risk, low risk, medium risk, and high risk. After that, a case study was conducted in the Dongting Lake area. We analyzed the impact of natural disasters under different scenarios (general scenario, pessimistic scenario and optimistic scenario), use Cobb-Douglas stochastic frontier model to predict resources constraint and inputs constraint on food supply, and evaluate the future food security risk under different scenarios. The results show that if annual grain shortfalls caused by natural disasters at the historical average level, there will be 2, 2 and 4 counties/cities at the low-risk range, medium-risk range and high-risk range in 2015, respectively; and the number of counties/cities at the medium-risk range will increase to 3 by 2020. If annual grain shortfalls caused by natural disasters at the historical worst level, there will be 2, 5 and 7 counties/cities at the low-risk range, medium-risk range and high-risk range in 2015, respectively; and the number of counties/cities at the high-risk range will increase to 9 by 2020. If annual grain shortfalls caused by natural disasters at the historical lowest level, there will be no significant changes in the risk range of all counties/cities. Overall, natural disaster is a main source of food supply risk and population growth is the most common risk factor that could cause food insecurity in the Dongting Lake area; Resources and input elements will have a positive impact for future food supplies in most counties and cities. However, there will be no gap between supply and demand of food if we are considering Dongting Lake area as a whole.