Shifts in climate change are strongly linked to human violence around the world, according to a comprehensive new study released Thursday by the University of California, Berkeley and Princeton University. The research, which was published in Science, examined 60 previous studies from all major regions of the globe. The results suggest that changes such as drought, flood, and high temperatures strongly correlate with spikes in conflict. 
Researchers noted examples including increased domestic violence in India and Australia, assaults and murders in the United States and Tanzania, ethnic violence in Europe and South Asia, land invasions in Brazil, police violence in the Netherlands, and civil conflicts throughout the tropics. The biggest culprit: higher temperatures. Out of 27 modern societies studied, all 27 showed a positive relationship between higher temperatures and violence. One standard deviation shift towards hotter conditions causes the likelihood of personal violence to rise four percent and intergroup conflict to rise 14 percent. If the study's calculations are correct, a global temperature rise of just 2 degrees Celsius could increase intergroup conflicts (such as civil wars) by over 50 percent. And, as Climate Central notes, projections estimate that temperatures will make that jump by 2040.
