Megadrought in US Worst In 1,200 Years: Study

A newly published study suggests the megadrought that has ravaged the US for the past 22 years is the worst in at least 1,200 years.

After exceptional drought severity in 2021, 19 per cent of which is attributable to anthropogenic climate trends, the years from 2000 to 2021 was the driest 22-year period since at least 800 AD, according to the study published in the journal Nature Climate Change.

This drought will very likely persist through 2022, matching the duration of the late 1500s megadrought, according to the study.

From 2000 to 2021, the precipitation in southwestern North America was 8.3 per cent below the average from 1950 to 1999, and temperature was 0.91 degrees Celcius above average.

No other 22-year period since at least 1901 was as dry or as hot, according to the study.

Aridity has dominated the region since 2000, as evidenced by declines in two of North America's largest reservoirs, Lakes Mead and Powell, both on the Colorado River.

In summer 2021, these reservoirs reached their lowest levels on record, triggering unprecedented restrictions on the Colorado River, said the study.

"Without climate change, this would not be even close to as bad as one of those historical megadroughts," said Park Williams, a climate scientist at the University of California, Los Angeles, and the study's lead author.

"The thing that is really remarkable about this drought period is that temperatures have been warmer than average in all of the years but one," he said.