Weather variability, agricultural revenues and internal migration: evidence from Pakistan

Migration is a widely used adaptation response to climate and weather variability. In this paper, we investigate how changes and variability in weather may affect internal migration through the agriculture channel. Using panel data for 50 districts of Pakistan, we estimate an instrumental variables regression model that allows us to analyse the impact of weather-driven changes in the crop revenue per hectare on the inter-district migration. Results show that temperature has a nonlinear effect, i.e. as temperature increases, the crop revenue per hectare initially increases and then declines. Furthermore, temperature variability has a negative effect on the expected crop revenue per hectare. A 1% weather-driven decrease in the crop revenue per hectare induces, on average, around 2% (0.02% point) decrease in the in-migration rate into a district. Predicted increases in temperature and its variability during 2016-2035 (relative to 1971-1998) are likely to decrease crop revenues in relatively warm districts and increase them in cooler districts. These effects would decrease the in-migration rate in 18-32 districts and increase the rate in the remaining districts. Thus, the extent and scope of the impacts of weather on migration in Pakistan depend on a district's geographic location and the variability of temperature in the future.