Climate conflict

The folklore of state conflict casts a long shadow — the patchwork quilt of nations tugged apart into a ghastly, mutually damaging disarray. Climate tugs at the individual threads of conflict, too: personal irritability, interpersonal conflict, domestic violence.

Heat frays everything. It increases violent crime rates, swearing on social media. The hotter it gets, the longer drivers will honk their horns in frustration.

By 2099, one speculative paper tabulated, climate change in the United States would bring about an additional 22,000 murders, 180,000 rapes, 3.5 million assaults, and 3.76 million robberies, burglaries, and acts of larceny. The statistics of the past are more inarguable, and even the arrival of air-conditioning in the developed world in the middle of the last century did little to solve the problem of the summer crime wave.

A team of researchers examining an enormous data set of more than 9,000 American cities found that air pollution levels positively predicted incidents of every single crime category they looked at — from car theft and burglary and larceny up to assault, rape, and murder. And then there are the ways that climate impacts can cascade into violence more circuitously.