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.
"We found that a one standard deviation shift towards hotter conditions causes the likelihood of personal violence to rise four percent and intergroup conflict to rise 14 percent," UC Berkeley's Marshall Burke, the study's co-lead author, wrote in a release.
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.
"We often think of modern society as largely independent of the environment, due to technological advances," coauthor Edward Miguel of UC Berkeley wrote. "But our findings challenge that notion."
Researchers were quick to add that climate is only one part of the cause of violent conflicts, noting that many contributing factors are deeply complex. However, they added, determining why climate contributes at all is an urgent question for future research.
Burke wrote that they hope the results "shed new light on how the future climate will shape human societies."