Here's today's disturbing statistic about human behavior. It appears that there's a strong correlation between hot, dry weather and high levels of violent human conflict. With temperatures heating up on Earth right now, that could mean we've got the biggest pre-crime map you've ever seen.

The Smithsonian's Joseph Stromberg has the story:

The team, led by Solomon Hsiang, specifically looked the historical relationship between climatic factors (temperature and rainfall fluctuations) and the incidence of all sorts of conflicts detailed in their source studies, which they grouped into the categories of personal crime (murder, domestic violence, rape and assault), intergroup violence (civil wars, ethnic violence and riots) and institutional breakdowns (collapses of governing bodies or even of entire civilizations such as the Mayan empire) . . .

They found that when temperatures or precipitation patterns in an area strayed from the norm, all three types of violence tended to increase, with intergroup conflict in particular surging the most during hotter periods. Specifically, a region that experienced a period of warming that fell beyond one standard deviation of average conditions saw 4 percent more personal crime and 14 percent more intergroup conflict over the period studied. In other words, assuming the variables fall in a bell curve around from average conditions, life became more violent for the roughly 32 percent of regions that significantly deviated away from average temperatures and precipitation rates . . .

Extrapolating to the future, these rates mean that if the entire planet went through an average of 3.6°F of warming by 2050—an optimistic limit set at the 2009 Copenhagen conference—we’d see personal crime rise by 16 percent and intergroup conflicts surge by 50 percent. The distribution of violence wouldn’t be equal, either, as climate models indicate that some areas will be hit with warming periods that fall outside two, three or even four standard deviations of the norm (and thus experience more conflict), as shown in the map below.

Obviously there are lot of caveats here. It's hard to analyze violent events in ancient history, and there are dozens of confounding factors that could create the illusion of a statistical correlation here. But let's say we are seeing a real correlation between warming weather, less rain, and more violence. Is it really the heat that's setting off violence, or droughts? My guess would be that famines, or the threat of famines, might be at the root of some of these conflicts — especially the historical ones.


Read more at The Smithsonian