Climate Variability and International Migration: The Importance of the Agricultural Linkage

While there is considerable interest in understanding the climate-migration relationship, particularly in the context of concerns about global climatic change, little is known about underlying mechanisms. We analyze a unique and extensive set of panel data characterizing annual bilateral international migration flows from 163 origin countries to 42 OECD destination countries covering the last three decades. We find a positive and statistically significant relationship between temperature and international outmigration only in the most agriculture-dependent countries, consistent with the widely-documented adverse impact of temperature on agricultural productivity. Specifically, each 1 °C increase in temperature implies a 5% increase in outmigration from agricultural countries. In addition, migration flows to current major destinations are especially temperature-sensitive. However, the sensitivity of outmigration to climate may be due to a country’s being poor, since most agricultural countries are also relatively poor. To address this concern, using an instrumental variables approach, we further estimate the effect of climate-driven cereal yield shocks on outmigration and find a significant effect only in agricultural countries, thus providing more direct evidence on the role of agriculture as the intermediate linkage between climate and international migration. Policies to address issues related to climate-induced international migration would be more effective if focused on the agriculture-dependent countries and especially people in those countries whose livelihoods depend on agriculture.