The Causal Effect of Heat on Violence: Social Implications of Unmitigated Heat Among the Incarcerated

Correctional facilities commonly lack climate control, producing a setting absent endogenous responses to hot weather like avoidance, adjustment, and mitigation. We study daily weather variation across the state of Mississippi, and show that high temperatures increase intense violence among the incarcerated. Days with unsafe heat index levels shift both the intensive and extensive margins of violence, raising daily violent interactions by 20%, and the probability of any violence by 18%. Our setting cleanly identifies the effect of heat on violence, and highlights previously unobserved social costs of current facility infrastructure. Rising global temperatures could substantially increase violence absent adjustment. Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.