Climatic factors as determinants of International Migration

In this paper, we examine environmental factors as potential determinants of international migration. We distinguish between unexpected short-run factors, captured by natural disasters, as well as long-run climate change and climate variability captured by deviations and volatilities of temperatures and rainfall from and around their long-run averages. We start from a simple neo-classical model, which is augmented to include environmental factors at origin in the form of amenities. We then test the model using a panel dataset of bilateral migration flows for the period 1960-2000, the time and dyadic dimensions of which additionally allow us to control for numerous time-varying and time invariant factors. Using our primary specification, having accounted for other well documented determinants of migration, we find no direct impact of climatic change on international migration in the medium to long run across our entire sample. These results are robust when further considering migrants returning home. Conditioning our regressions upon origin country characteristics, we find evidence that shortfalls in precipitation constrain migration to developing countries from those which rely more heavily upon agriculture and spur movements to developing countries from those with fewer groundwater reserves. We further use the rate of urbanization as a proxy for internal migration and find strong evidence that natural disasters beget greater flows of migrants to urban environs.