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.

Climate Change, Agriculture and Migration: A Survey

“…However, looking at a specific climate change measure such as precipitation, several studies find no significant effect on internal migration. No effect on within-or across-village migration is found in [65], where the case of Pakistan is analyzed. According to [66], rainfall does not affect the migration propensity of people living in agricultural communities in Ghana, even if their household economy depends on agriculture.…”

“…A further rise in baseline temperature in the US Corn Belt has been shown to raise internal migration due to its effect on crop yields [67]. Inter-provincial migration of households due to temperature anomalies was observed in Indonesia [68] and, for male migrants, in the case of Pakistan [65]. Furthermore, in a study concerning the US [69], as well as in other studies at the micro-level, climate shocks, as captured by measures of temperature, humidity, and wind, have been shown to result in short-distance internal migration [52,60,70,71].…”

“…In such a context, climate changes have been framed as first affecting agricultural production and then acting on individual and household migration behavior through related effects on livelihoods [65,83]. The importance of agriculture as a mediating channel in the relationship between climate change and migration emerges clearly from both the micro-level country studies and the relatively few macro-level analyses using cross-sectional data over longer time periods.…”

“…In a study referring to Pakistan [65], the authors use a longitudinal panel survey (1991-2012) to look at the relationship between weather variations and long-term migration. They examine the effect of climate changes on annual income for farmers and non-farmers during the 1986-1991 period, finding negative agricultural income variations when temperatures are extremely hot, while flood has almost no significant impact on migration.…”

Climate Change and Migration: A Dynamic Model

“…Gray and Mueller (2012) offer evidence that climate change has contributed to migratory pressures in Bangladesh. Mueller et al (2014) argue that heat stress has lead to permanent migration from Pakistan.…”