The extreme weather conditions that have dried out North America’s Southwest over the past 22 years have now become the region’s driest “megadrought” since the year 800, a new study has found.
The ongoing megadrought has displaced the previous record-holder: which was a late-16th century dry spell previously considered the worst such drought in the past 1,200 years, according to the study, published on Monday in Nature Climate Change.
“Without climate change, the past 22 years would have probably still been the driest period in 300 years,” Park Williams, lead author and a geographer at UCLA, said in a statement. “But it wouldn’t be holding a candle to the megadroughts of the 1500s, 1200s or 1100s,” he added.
The scientists focused on the area from southern Montana to northern Mexico, from the Pacific Ocean to the Rocky Mountains, finding several megadrought periods from 800 through 1600 that exceeded any subsequent event.
The scientists found that since the year 2000, the average soil moisture deficit was twice as severe as the deficit in any 20th century drought, which surpassed the driest periods of all the most severe megadroughts in the past 1,200 years.
Although the scientists agreed that climate change has become a significant driver of megadroughts, they also acknowledged that some dramatic shifts in dryness and water availability occurred in the Southwest before human-induced climate change became a factor in the 20th century.
Well before humans began inflicting their carbon footprint upon the Southwest, the region was experiencing “infamous megadroughts that occurred repeatedly from 800-1600,” the study said.
As of just last week, the U.S. Drought Monitor indicated that 95 percent of the Western U.S. was experiencing drought conditions, while in the summer of 2021, the Colorado River’s two main reservoirs, Lake Mead and Lake Powell had plummeted to their lowest levels since record-tracking began in 1906, the authors noted.
With dry conditions likely to persist in the region, the scientists estimated that it would take multiple wet years to repair any damage done.
ARTICLE: PAUL MURDOCH
MANAGING EDITOR: CARSON CHOATE
PHOTO CREDITS: WASHINGTON POST