系统风险、交易成本与农业天气指数保险的区域划分--与传统农业保险的比较研究

As a risk reducing and risk transferring mechanism, crop insurance has been utilized by many developed counties as an efficient risk management tool. And as a "green box" policy under the WTO framework, being allowed to provide financial support and income subsidies to farmers, in many countries, agricultural insurance also partly act as an income transfer payments policy tool. Traditional agricultural insurance, in which the payment is calculated according to the actual yield losses of farmers, is taken for as inefficient, due to serious moral hazard and high transaction costs in the process of risk diversification and income transferring. Whereupon, high transaction costs will aggravate fiscal leakage, so weaken efficiency of income transfer. Index-based weather insurance, WIBI for short, where indemnities are paid based solely on the realized value of the underlying index, is more efficient on risk reduction as it can resolve the moral hazard, reduce adverse selection and operational costs (or transaction costs). Compared with traditional crop insurance (Indemnity-based Crop Insurance), WIBI can better guard against adverse selection and moral hazard , not to carry out inspections and assessment of the damage, reducing the cost of claims, and therefore the cost of management of insurance is very low . Nevertheless, also as a "green box" policy under the WTO framework, being allowed to provide income subsidies to farmers, WIBI is more efficient. WIBI should be used for hedging systemic risk --high correlation among farm-level yields . WIBI requires the insured farmer's crop loss is closely related to the underlying index; otherwise, there may be a gap between compensation and loss, resulting in unable to effectively spreading risk ( basis risk). To sum up, although traditional crop insurance is heavily criticized, for WIBI, whether the reduction of transaction costs can offset the higher compensation due to basis risk for ? This is an empirical study in our research. The questions we will answer include, how to zone and measure the risk based on the standard of cost and efficiency both for WIBI and traditional agricultural insurance, how to define the boundaries? To answer the above questions, first we need to make comparison of the premium rate and efficiency between WIBI and traditional agricultural insurance, on the basis of risk assessment. Then, we will measure how systematic risk and transaction costs impact on premium rate and efficiency, in order to find the boundary condition between two insurances and make a zoning. This will provide an efficient analysis framework and reliable empirical supports for the agricultural risk management. Research findings will not only provide the basis for the choice of public policy, but also helps to reinforces understanding of the spacial distribution pattern of agricultural risk and promote the integration of agricultural economy and meteorology.

根据实际产量损失赔付的传统农业保险在分散风险与收入转移中往往因高昂的交易成本而效率低下, 而基于天气变化情况进行赔付的天气指数保险可以有效避免传统农业保险的难题，降低交易成本、提高风险分散和收入转移的效率。但是，天气指数保险似应覆盖系统性较强的风险，否则天气指数保险的赔付成本可能会高于传统的农业保险。因此，两种保险之间的关系定位与审慎选择尤为重要。 本课题将在成本效率统一的标准下，构建天气指数保险和传统农业保险的适宜区域划分的分析框架。在综合考虑交易成本和系统风险的影响下，进行费率精算与效率评估，对天气指数保险与传统农业保险适宜的区域与风险进行划分，界定天气指数保险与传统的农业保险的政策定位（替代、互补，还是划分不同风险、不同区域开展）。 研究成果不仅为公共政策的选择提供依据，也有助于加深对农业风险时空规律的理解，推动农业经济与农业气象等学科的交叉与融合。

根据实际产量损失赔付的传统农业保险在分散风险与收入转移中往往因高昂的交易成本而效率低下, 而基于天气变化情况进行赔付的天气指数保险可以有效避免传统农业保险的难题，降低交易成本、提高风险分散和收入转移的效率。但是，天气指数保险似应覆盖系统性较强的风险，否则天气指数保险的赔付成本可能会高于传统的农业保险。因此，两种保险之间的关系定位与审慎选择尤为重要。.本课题将在成本效率统一的标准下，构建天气指数保险和传统农业保险的适宜区域划分的分析框架。在综合考虑交易成本和系统风险的影响下，进行费率精算与效率评估，对天气指数保险与传统农业保险适宜的区域与风险进行划分，界定天气指数保险与传统的农业保险的政策定位（替代、互补，还是划分不同风险、不同区域开展）。.研究主要内容包括需求层面上探讨两种保险之间的替代或互补关系，研究了两种保险的成本与效率比较、系统风险的衡量以及作用；天气指数保险的设计和费率精算；天气指数保险的风险区域划分。研究的重要成果集中在利用蒙特卡洛模拟的方法证明了系统风险强的区域天气指数保险会更加有效率，同时利用固定观察点微观数据对全国天气指数保险比较适宜的区域进行了划分，也在微观层面上实证了天气指数保险和传统农业保险既有替代性又有互补性。因此，天气指数保险如果作为传统农业保险的替代产品，应该在系统性较强的区域和风险下开展，如果天气指数保险作为传统农业保险的补充，可以作为提高保险金额的附加产品，同时有利于弥补传统农业保险的一些问题，提高农户的满意度。研究成果具有一定的应用意义，也有很强的政策含义。