Global power grids are about to face their biggest test in decades with electricity generation strangled in the world’s largest economies.

War. Drought. Production shortages. Historically low inventories. And pandemic backlash. Energy markets across the planet have been put through the wringer over the past year, and consumers have suffered the consequences of soaring prices. But, somehow, things are on track to get even worse.

Blame the heat. Summer in much of the Northern Hemisphere is a typical peak for electricity use. This year, it’s going to be sweltering as climate change tightens its grip. It’s already so hot in parts of South Asia that the air temperatures are blistering enough to cook raw salmon. Scientists are predicting scorching months ahead for the U.S.