April 5, 2021, Paper: "We consider the effects of climate change on seasonally migrant populations that herd livestock – i.e., transhumant pastoralists – in Africa. Traditionally, transhumant pastoralists benefit from a cooperative relationship with sedentary agriculturalists whereby arable land is used for crop farming in the wet season and animal grazing in the dry season. Droughts can disrupt this arrangement by inducing pastoral groups to migrate to agricultural lands before the harvest, causing conflict to emerge. We examine this hypothesis by combining ethnographic information on the traditional locations of transhumant pastoralists and sedentary agriculturalists with high-resolution data on the location and timing of rainfall and violent conflict events in Africa from 1989–2018. We show that droughts in the territory of transhumant pastoralists lead to conflict in neighboring agricultural areas. Additionally, (i) the conflict is concentrated in the wet season and not the dry season; and (ii) the mechanism operates through rainfall’s effect on plant biomass growth. We also find that this effect on conflict is greater in countries where pastoral groups have less political power. The magnitudes of our estimates indicate that nearly all of the reduced-form relationship between adverse rainfall shocks and conflict in Africa is explained by this mechanism."
Non-HKS Author Website - Nathan Nunn