Tens of millions were battling dangerously high temperatures in the United States on Saturday as record heat forecasts hung over Europe and Japan, in the latest example of the threat from global warming.
A powerful heat wave stretching from California to Texas was expected to peak as the U.S. National Weather Service warned of an "extremely hot and dangerous weekend."
Daytime highs were forecast to range between 10 and 20 degrees Fahrenheit above normal in the west.