We examine natural disasters and long-run climatic factors as potential determinants of international migration, implementing a panel dataset of bilateral migration flows from 1960 to 2000. We find no direct effect of long-run climatic factors on international migration across our entire sample. These results are robust when conditioning on origin-country characteristics, when considering migrants returning home, and when accounting for the potential endogeneity of migrant networks. Rather, we find evidence of indirect effects of environmental factors operating through wages. We find that epidemics and miscellaneous incidents spur international migration, and there is strong evidence that natural disasters beget greater flows of migrants to urban environs.