As the climate crisis progresses, the number of extremely hot days around the US could more than double, according to a peer-reviewed study and report from the Union of Concerned Scientists.

By mid-century, an average of 36 days a year could feel like 100F (37.7C) or hotter. Toward the end of the century, 54 days a year could feel that hot, researchers with the science advocacy group found.

The new data comes as an oppressive heat wave spreads across the eastern two-thirds of the United States, with heat warnings and advisories issued in nearly half of all US states. The heat…