贸易、储存与气候极端：来自撒哈拉以南非洲的理论与证据

中文摘要

气候极端事件日益威胁发展中国家的粮食安全。本文构建了一个整合消费平滑、储存与贸易的动态随机模型, 以考察农业市场如何缓冲气候引发的粮食短缺。该理论框架为理解家庭市场交易成本、借贷约束以及时空气候模式的作用提供了新的见解。在此理论基础上, 本文对撒哈拉以南非洲12个国家季度和次国家层面的粮食不安全、气候极端事件与通行时间开展了大规模实证分析。实证结果表明, 在前往城市通行时间更长的地区, 本地干旱条件对粮食不安全的加剧更为严重; 而在距离港口更远的地区, 国家层面干旱条件的影响更强。各国的进口能力与库存缓冲了国家层面气候极端事件对粮食不安全的影响。部分实证结果与理论预测存在偏离, 表明有必要进一步研究基于市场的消费平滑机制的运行。

Abstract

Climate extremes increasingly threaten food security in developing countries. This paper develops a dynamic stochastic model integrating consumption smoothing, storage, and trade to examine how agricultural markets buffer climate-induced food shortages. The theoretical framework provides new insights on the role of household market transaction costs, borrowing constraints, and spatiotemporal climate patterns. Building on the theory, the paper conducts a large-scale empirical analysis of food insecurity, climate extremes, and travel times at quarterly and subnational level across 12 Sub-Saharan African countries. The empirical results show that local dry conditions exacerbate food insecurity more severely in regions with longer travel times to cities, while country-level dry conditions have stronger effects in regions farther from ports. Countries’ import capacity and stocks buffer the food insecurity impact of country-level climate extremes. Some empirical results diverge from the theoretical predictions, pointing to the need for further research on the functioning of market-based consumption smoothing.