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 from1989–2018. We show that droughts in the territory of transhumant pastoralists lead to conflict in neighboring agricultural areas. Additionally,
- the conflict is concentrated in the wet season and not the dry season; and
- 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. Nathan Nunn is Frederic E. Abbe Professor of Economics at Harvard University. Professor Nunn’s primary research interests are in political economy, economic history, economic development, cultural economics, and international trade. He is an NBER Faculty Research Fellow, a Research Fellow at BREAD, a Faculty Associate at Harvard’s Weatherhead Center for International Affairs (WCFIA), and a Fellow of the Canadian Institute for Advanced Research (CIFAR) in the Boundaries, Membership & Belonging program.
One stream of Professor Nunn’s research focuses on the historical and dynamic process of economic development. In particular, he has studied the factors that shape differences in the evolution of institutions and cultures across societies. He has published research that studies the historical process of a wide range of factors that are crucial for economic development, including distrust, gender norms, religiosity, norms of rule-following, conflict, immigration, state formation, and support for democracy. Another stream of Professor Nunn’s research examines economic development in a contemporary context. He has published research examining the effects of Fair Trade certification, CIA interventions during the Cold War, foreign aid, school construction, and trade policy.
He is particularly interested in the importance of the local context (e.g., social structures, traditions, and cultures) for the effectiveness of development policy and in understanding how policy can be optimally designed given the local environment. Specifically, he has studied the relationship between marriage customs and female education, generalized trust and political turnover, the organization of the extended family (lineage) and conflict, and traditional local political systems and support for democracy. His current research interests lie in better understanding the importance of local culture and context for economic policies, particularly in developing countries.
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