Study: Worst SW drought in 1,000 years coming

That’s the message of a new study written by scientists at Columbia and Cornell universities and released Thursday.

Due to human-caused global warming, this region and the Great Plains are likely to experience droughts from 2050 to 2100 that are worse than the “megadroughts” that lasted up to 60 years in the Southwest in pre-Medieval times, the study said.

By 2100, this area will not only be drier than during today’s drought, but the future drought will probably last much longer than the current 20-year-long drought, said Jason Smerdon, one of the authors.

The current drought in the Colorado River Basin is the worst and longest-lasting since historical records have been kept starting in the early 20th century. It’s caused Lake Mead at the Nevada border to drop to its lowest level on record, threatening future shortages of Central Arizona Project water for farmers and ultimately cities.

Looking at the Southwest and southern Great Plains, the current drought directly affects more than 64 million people, a news release accompanying the study said.

The risk of one of these major droughts will rise from 12 percent in the 2050s to more than 80 percent at the end of the 21st century, said Smerdon. The impacts of such a future drought could be devastating for this region, given its much larger population and use of resources today than 1,000 years ago, the authors said in a news release.

“We are the first to do this kind of comparison (with past megadroughts) ... and the story is a bit bleak,” said Smerdon, a climate scientist at Columbia. “Even when selecting for the worst megadrought-dominated period, the 21st century projections make the megadroughts seem like quaint walks through the Garden of Eden.”

The study is being published in the inaugural edition of the online journal Science Advances, produced by the American Association for the Advancement of Science. The association also publishes the journal Science.

While the new study didn’t make forecasts for the Colorado River, “It is likely that any related water resources in the region will be further stressed and reduced as the area continues to dry into the future,” Smerdon said.