Heat Stress Increases Long-term Human Migration in Rural Pakistan

Abstract

Human migration attributable to climate events has recently received significant attention from the academic and policy communities (1-2). Quantitative evidence on the relationship between individual, permanent migration and natural disasters is limited (3-9). A 21-year longitudinal survey conducted in rural Pakistan (1991-2012) provides a unique opportunity to understand the relationship between weather and long-term migration. We link individual-level information from this survey to satellite-derived measures of climate variability and control for potential confounders using a multivariate approach. We find that flooding-a climate shock associated with large relief efforts-has modest to insignificant impacts on migration. Heat stress, however-which has attracted relatively little relief-consistently increases the long-term migration of men, driven by a negative effect on farm and non-farm income. Addressing weather-related displacement will require policies that both enhance resilience to climate shocks and lower barriers to welfare-enhancing population movements.

Figure 1. Predicted Probabilities of Out-of-Village Migration by Gender.

The bubble size reflects the predicted probabilities obtained using Specification C under different temperature and rainfall extreme scenarios (Supplementary Table 5). Solid teal green bubbles indicate the probability of men moving out of the village in a given scenario. Black dashed bubbles indicate the probabilities of women moving out of the village in a given scenario. Predicted probabilities are specified for the scenario where the temperature and rainfall lie in the interquartile range and extreme hot scenario (low rainfall, high temperature) for reference and differentiated by color for the gender of migrants.