Washington, United States—Climate change is causing heat waves to slow to a crawl, exposing humans to extreme temperatures for longer than ever before, a study published in Science Advances said Friday.
For every decade between 1979 to 2020, researchers found heat waves slowed down by an average of five miles an hour per day. The researchers divided the world into three dimensional-grid cells and defined heat waves as a million square kilometer zones, where temperatures reached at least the 95th percentile of the local historical maximum temperature. They then measured their movement over time in order to determine how fast the hot air was moving.They also used climate models to determine what the results would have looked like absent human-caused climate change, and found manmade factors loomed large.
The changes have accelerated in particular since 1997 and in addition to human causes, weakening upper atmospheric air circulation may play a part, the paper said.