In Cantua, a small town deep within California’s farming heartland, the heat had always been a part of life. “We can do nothing against it,” said Julia Mendoza, who’s lived in this town for 27 years. But lately, she says, the searing temperatures are almost unlivable.

By midday on Thursday, the first day of a protracted, extreme heatwave in California’s Central Valley, the country roads were sizzling with heat. A young volunteer with a local environmental justice non-profit who had come to check in on the neighborhood collapsed on the sidewalk, her face bright red and damp. Construction crews working nearby quickly swept her into an air-conditioned car and handed her a cold bottle of water.