This summer of fire and swelter looks a lot like the future that scientists have been warning about in the era of climate change, and it’s revealing in real time how unprepared much of the world remains for life on a hotter planet.

The disruptions to everyday life have been far-reaching and devastating. In California, firefighters are racing to control what has become the largest fire in state history. Harvests of staple grains like wheat and corn are expected to dip this year, in some cases sharply, in countries as different as Sweden and El Salvador. In Europe, nuclear power plants have had to shut down because the river water that cools the reactors was too warm. Heat waves on four continents have brought electricity grids crashing.

And dozens of heat-related deaths in Japan this summer offered a foretaste of what researchers warn could be big increases in mortality from extreme heat. A study last month in the journal PLOS Medicine projected a fivefold rise for the United States by 2080. The outlook for less wealthy countries is worse; for the Philippines, researchers forecast 12 times more deaths.

Globally, this is shaping up to be the fourth-hottest year on record. The only years hotter were the three previous ones. That string of records is part of an accelerating climb in temperatures since the start of the industrial age that scientists say is clear evidence of climate change caused by greenhouse gas emissions.