Econ Papers Daily / 期刊论文
贸易多样化与粮食价格波动
Trade diversification and food price volatility
摘要
Recent shortages and price volatility have exposed vulnerabilities in international agri-food value chains. This paper develops a new framework for measuring trade diversification based on Hill numbers, which capture both the extensive and intensive margin of trade connections. Using HS6-level bilateral data for 188 countries from 2000 to 2022, I first document global patterns of diversification and concentration across agri-food sectors. The descriptive evidence shows that most countries trade with many partners in principle, yet effectively rely on only a few, especially for grains and oilseeds. I then estimate the effect of import and export diversification on within-year food price volatility using a shift–share instrumental-variable design that exploits exogenous foreign sector-level shocks weighted by lagged bilateral trade exposure. The empirical results show that more balanced and diversified import portfolios are strongly associated with lower food price volatility, whereas export diversification plays a more limited role. Policies encouraging diversification can reduce food price volatility but involve trade-offs between efficiency from international specialization and resilience of the input–output network.
中文摘要
近期短缺与价格波动暴露了国际农食价值链的脆弱性。本文基于Hill数构建了一个衡量贸易多样化的新框架，该框架同时捕捉贸易联系的广延边际与集约边际。利用2000年至2022年188个国家HS6位级双边数据，本文首先刻画了农食各行业多样化和集中化的全球格局。描述性证据表明，多数国家原则上与众多伙伴开展贸易，但实际上仅依赖少数伙伴，谷物和油籽尤为突出。随后，本文采用偏移-份额工具变量设计，利用以滞后双边贸易暴露度加权的外国行业层面外生冲击，估计进口和出口多样化对年内粮食价格波动的影响。实证结果表明，更为均衡和多样化的进口组合与更低的粮食价格波动强烈相关，而出口多样化的作用则较为有限。鼓励多样化的政策能够降低粮食价格波动，但需要在国际专业化带来的效率与投入产出网络的韧性之间进行权衡。