Heat and Drought Reduce Subnational Population Growth in the Global Tropics.

Abstract

In recent decades, the possibility that climate change will lead to depopulation of vulnerable areas in the global tropics via migration, mortality, or collapsing fertility has generated significant concern. We address this issue by using data on subnational population growth from 1,809 subnational units across the global tropics and linked data on climate exposures to examine how decadal temperature and precipitation anomalies influence population-weighted intercensal growth rates. Our fixed effects regression analysis reveals that the lowest predicted population growth rates occur under hot and dry conditions. The effects of heat and drought are strongest in districts that, at baseline, have high population densities, high precipitation rates, or high educational attainment. These patterns are contrary to common assumptions about these processes, and even the rare combination of hot and dry conditions, occurring in less than 7% of our sample, does not lead to local depopulation. Taken together with previous findings, this suggests that depopulation narratives do not have a strong evidentiary basis.