By mid-century, a third of Americans will live in dangerously hot areas, report predicts

Intense heat this summer has set records in the U.S., with some regions topping 110 degrees. Utah residents suffered through 16 straight days of triple-digit heat — the longest such stretch in the 125 years that records have been kept. Around the world, extreme temperatures have killed thousands in Asia and Europe.

Despite this alarming picture of the present, it is likely just the beginning. By mid-century, nearly one-third of U.S. adults are likely to live in counties that experience hazardous heat, according to a new analysis from the First Street...