In ancient Southwest droughts, a warning of dry times to come | Science News

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Reconstructions

In ancient Southwest droughts, a warning of dry times to come

By
4:15pm, August 1, 2011

Anything but lush, the U.S. Southwest has been especially parched lately. About a decade ago a cycle of droughts began; the latest one has dried much of the region to a degree that meteorologists expect only twice a century.

But look back a millennium or more, and you’ll find signs that today’s conditions are not all that unusual. Studies of ancient climate suggest that the last decade’s water crisis, and even the 1930s Dust Bowl, pale in comparison to a series of droughts that struck the Southwest 700 to 1,100 years ago.

Temperature was the driving force behind those ancient droughts; solar activity warmed western North America by up to 1 degree Celsius above the long-term average. With temperatures today rising once again — this time due not to solar variation but to increasing atmospheric carbon dioxide levels — there’s every indication the Southwest is about to get even drier.

It’s already warm

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