By Doyle Rice | USA TODAY
If you think it’s hot now, just wait. Heat waves are becoming more frequent globally. But how do we measure heat waves?
They’re coming back.
Megadroughts – defined as intense droughts that last for decades or longer – once plagued the Desert Southwest. In fact, from the 9th to the 15th centuries, at least a dozen medieval megadroughts occurred across the region, scientists said.
Now, a study suggests that because of the drying influence of climate change, megadroughts could return to the region.
Megadroughts are defined more by their duration than their severity. They are extreme dry spells that can last for a decade or longer, according to the National Oceanic and Atmospheric Administration.
They’ve parched the West, including present-day California, long before Europeans settled the region in the 1800s.
Most of the USA’s droughts of the past century, even the infamous 1930s Dust Bowl that forced migrations of Oklahomans and others from the Plains, “were exceeded in severity and duration multiple times by droughts during the preceding 2,000 years,” the National Climate Assessment said.
