Climate Change and Rising Violence Are Linked, According to 55 Scientific Studies

According to a new review of 55 separate studies, there is a meaningful connection between climate change and human violence.

The working paper, put out by researchers with the National Bureau of Economic Research, is what’s called a meta-analysis:  a study of studies, in effect. After going through numerous analyses of the relationship between climate change and violence in various settings, the researchers settled on 55 of the most rigorous pieces of work.  They then evaluated the picture painted by those studies, and worked to amalgamate their findings into a single statistical result.

They looked at conflicts between individuals — “domestic violence, road rage, assault, murder, and rape” — as well as conflicts between larger human groups — “riots, ethnic violence, land invasions, gang violence, civil war and other forms of political instability, such as coups.”  The end result?  The researchers determined that changes in drought and rainfall patterns, but especially increases in temperature, all have a meaningful link to increases in both forms of violence.  “We find that deviations from moderate temperatures and precipitation patterns systematically increase the risk of conflict, often substantially, with average effects that are highly statistically significant,” the researchers wrote.

Statistical significance is technical term meaning that the researchers’ numbers are robust enough to point to a real phenomenon in the populations their meta-analysis covered.  It doesn’t confirm exactly what is going on; there could still be a correlation-versus-causation problem between climate change and violence, for example.  But it does mean Burke and his colleagues aren’t being fooled by random noise in the data.

The effects are different for different parts of the globe.  Stanford researcher Marshall Burke, one of the study’s three co-authors, told Chris Mooney at the Washington Post that “for a degree Celsius of temperature increase (1.8 degrees Fahrenheit) … there could be a 20 percent increase in civil conflict in Africa.”  In the United States, meanwhile, every one degree Celsius increase in warming should bring “a one percent increase in interpersonal conflicts.”

Climate Change and Rising Violence Are Linked, According to 55 Scientific Studies