Climate Change Intensified the Deadly Pacific Northwest Heatwave

Last week’s deadly heat in the northwestern U.S. and British Columbia would not have reached the highs it did in a world without greenhouse gas pollution, according to climate scientists who conducted a rapid-response study of the heatwave.

“We’ve never seen a jump in record temperature like the one in this heatwave,” said Geert Jan van Oldenborgh, a weather and climate researcher at the Royal Netherlands Meteorological Institute.

The event was so rare that the researchers were unable to estimate a full range of probabilities, concluding only that humanity’s warming of the planet made it at least 150 times more likely. They ...