Input Sourcing under Climate Risk: Evidence from U.S. Manufacturing Firms
利用美国制造业进口交易数据，基于海运时间的历史波动构建投入品采购风险指标，发现天气导致的运输延误显著降低进口商的销售、利润和就业，而企业通过增加航线和供应商来分散风险。
Abstract We study the effect of risk on how firms organize their supply chains. We use transaction-level data on U.S. manufacturing imports to construct a novel measure of input sourcing risk based on the historical volatility of ocean shipping times. Our measure isolates the unexpected component of shipping times that is induced by weather conditions along more than 331,000 maritime routes. We first document that unexpected shipping delays significantly reduce importers’ sales, profits, and employment. We then show that firms actively diversify weather risk by using more routes and foreign suppliers, although their import values decline. To rationalize these findings, we introduce shipping time risk into a general equilibrium model of importing with firm heterogeneity. Our quantitative analysis predicts substantial costs for the U.S. economy associated with supply chain risk.