Might be a Neo Oligocene Climate: US may Have Megadrought in Southwest, Midwest by Century end?

The intricate sandstone ruins of Chaco Canyon, New Mexico—a once thriving settlement abandoned in the 13th century by the ancient Pueblo peoples during a decades-long “megadrought”—serve as a silent reminder to all who live in the arid regions: When water supplies dwindle, even sophisticated societies may not be able to adapt.

Now, new research suggests that the severe, 60-year drought that likely helped empty Chaco Canyon was a preview of longer, hotter dry spells to come as a result of climate change. The Chaco drought will look “quaint” compared with what computer models predict will hit the midwestern and southwestern United States over the next century, says Jason Smerdon, a climate scientist at Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York, and co-author of the new study, published this week in Science Advances.

Warnings that droughts will intensify as the climate warms are not new. But this forecast gains credibility, other researchers say, because Smerdon and colleagues developed detailed forecasts of soil moisture—a key drought measure—and put those predictions into historical perspective. The study is “the most sophisticated effort I've seen by far to connect records of ancient droughts with projections of future change,” says Jonathan Overpeck, a geologist and atmospheric scientist at the University of Arizona in Tucson.

How global warming will affect specific regions is one of the thorniest questions in climate science. Previous studies have suggested that, in a warming world, existing weather patterns will intensify, causing wet regions of North America to get wetter and dry regions drier, with the Southwest experiencing the worst droughts first. To add detail to that picture, the researchers used 17 state-of-the-art climate models to forecast three different measures of soil moisture over the next 100 years as the warming climate alters rainfall and speeds evaporation. The models also took into account variables such as wind speed and humidity.

The results were striking. In nearly every climate model, the projections pointed to severe drying in the Southwest and Midwest by the end of the century if greenhouse gases continue to build up. “If models that are all constructed a bit differently all converge on the same answer, that gives us confidence that we are getting the right answer,” says co-author Benjamin Cook of the NASA Goddard Institute for Space Studies in New York City.

link.

hrm.  The precipitation sims are still not yet there.  I'd still be wary.