“This heat wave all across the West is a signal of climate change,” says Leah Stokes, a climate and energy policy expert at the University of California, Santa Barbara. “And this situation tells us we need to take some serious steps to get on track toward a zero-emissions future.”

California currently gets more than 30 percent of its electricity from renewable sources, primarily solar and wind, but not counting large hydroelectric dams. Under its 2018 climate law, the state plans to increase the renewable contribution to 60 percent by 2030. By 2045, 100 percent of its electricity is to be “zero-carbon”—but under the law that last 40 percent may include large hydro and even nuclear, if any is available.