Higher temperatures fuel gun violence. Now we know how much is from climate change.

This story was originally published , a nonprofit newsroom covering gun violence in America.​ This year, Philadelphia is on track to have the lowest number of homicides since 1963. But over Fourth of July weekend, a heat dome stretching from Maine to the Gulf of Mexico descended, leaving 165 million people facing major or extreme heat. Cities including Boston, Baltimore, and Raleigh saw record temperatures, and readings in Philadelphia topped 100 degrees for three consecutive days. The sweltering city also saw a busy weekend for gun violence. Between July 2 and July 4, the Gun Violence Archive recorded nine shootings, leaving three dead and nine wounded. “Those who commit gun violence are in a vulnerable population that have limited economic ability to make sure that they have air conditioning,” said Marion Campbell, executive director of Eddie’s House, a Philadelphia nonprofit that provides violence prevention and social services to such populations. “When you get hot you get irritated, OK! I’m just going to keep it real. You get irritated and your inability to manage your frustration could be heightened.” Grist thanks its sponsors. To support our nonprofit environmental journalism, please consider disabling your ad-blocker to allow ads on Grist. Here's How Research confirms what Campbell and others see on the ground: When temperatures rise, gun violence increases. What was previously unknown was the effect of climate change on gun violence. A new finding shared with The Trace , a nonprofit focused on climate change research and communication, estimates that approximately 2,000 shootings between 2021 and 2025 in the 100 U. S. cities with the most gun violence are attributable to high temperatures made more likely . In fact, the baking July Fourth weekend in Philadelphia was at least twice as likely to occur due to climate change, according to Climate Central. And this is only the beginning. As temperatures continue to rise, even more upward pressure on gun violence is likely. To support our nonprofit environmental journalism, please consider disabling your ad-blocker to allow ads on Grist. Here's How “Across all of these cities, we see that in aggregate, climate change is raising the risk of gun violence,” said Kristina Dahl, vice president for science at Climate Central. “Short of really swift and deep cuts to heat-trapping emissions globally, we expect the planet to continue to warm,” Dahl said. The theory that increased temperatures correspond with increased violence is well established, said John Roman, a distinguished senior fellow at the University of Chicago’s NORC social research center, whom The Trace asked to review the Climate Central analysis.