Deviations from normal precipitation and mild temperatures systematically increase the risk of conflict, often substantially. This relationship is apparent across spatial scales ranging from a single building to the globe and at temporal scales ranging from an anomalous hour to an anomalous millennium. Each 1-SD change in climate toward warmer temperatures or more extreme rainfall increases the frequency of interpersonal violence by 4% and intergroup conflict by 14% (median estimates)... Amplified rates of human conflict could represent a large and critical social impact of anthropogenic climate change in both low- and high-income countries. The overgrazing of land and a rapidly growing population have compounded the land-desertification process. As previously fertile lands turn to dust, farmers and herders have had no choice but to move elsewhere, starve, or demand change.