Historical and future influence of climate on human violence

Abstract:

We quantitatively review and synthesize a growing literature that studies the link between changes in climate and human violence. Drawing from archeology, criminology, economics, geography, history, political science, and psychology, we find robust evidence that changes in climate -- particularly warming temperature -- are related to a range of violent outcomes, including large-scale group conflict, interpersonal conflict, and self-harm. These relationships are observed on all continents and at multiple temporal scales. We show that historical warming has increased the probability of multiple large conflict events that were observed, some substantially. We show that absent unprecedented adaptation, future warming could lead to large increases in a range of violent outcomes around the world, with large human and economic cost.