A new study shows that a massive drought that has raged in the southwest of the United States for at least 20 years is putting the region in its driest period in 1,200 years, the ABC website reported Feb. 15.
According to a new study published in the journal Nature Climate Change on the 14th, researchers learned about the long-term soil moisture in the local area by analyzing the annual ring patterns of trees in parts of North America (from southern Montana to northern Mexico, from the Pacific coast to the Rocky Mountains), and found that the severity of this mega-drought exceeded that of another in the late 16th century, the driest drought since 800 AD.
Since 2000, the region's average soil moisture deficit has been twice as severe as any drought of the 20th century. Even driest areas are worse than the worst major droughts of the past 12 centuries. These findings are confirmed by comparison with historical climate data. According to the National Oceanic and Atmospheric Administration (NOAA), the term "megadrought" is used to describe severe droughts that have lasted for decades.
According to the study, human-caused climate change since 2000 has caused about 42 percent of the region's soil to be dehydrated. But researchers also found that from 800 to 1600 AD, mega-droughts were repeated in the region, but existing climate models suggest that even without considering climate change, current droughts would be "dry," just not to that extent.
Park Williams, a geographer at UCLA and author of the study, said in a statement that high temperatures and low precipitation from the summer of 2020 to summer 2021 exacerbated an already worrying situation, requiring multiple rainy years to correct the effects of drought. He said the drought would not end in a rainy year.
According to the study, from 2000 to 2021, the average temperature in the region was 1.64 degrees Fahrenheit higher than the average temperature from 1950 to 1999.
According to the U.S. Drought Monitor, nearly 95 percent of the western U.S. had experienced drought as of Thursday. Last summer, Lakes Mead and Powell saw their lowest water levels on record, according to the U.S. Bureau of Farm Reclamation.
Daniel Swain, a climate scientist at the University of California, Los Angeles, told ABC News last June that "essentially, half of the severity of the current great drought is caused by warming temperatures, and without this warming, it can be said that this drought would not have been a 'mega-drought' at all." ”
To protect water, U.S. federal officials cut water allocations in several southwestern states last August to cope with the low water level of the Colorado River. Last October, California Governor Gavin Newsom declared a "drought emergency" and asked Californians to take the initiative to reduce water use by 15 percent.
(Editor: LH)