Southwest U.S. Ice Age Climate Studied

TUCSON, Jan. 26 (UPI) — A U.S. geoscientist says she’s found the abrupt changes in ice age climate known to have occurred in Greenland also occurred in the southwestern United States.

University of Arizona Professor Julia Cole says her finding is the first to document the simultaneous events.

“It’s a new picture of the climate in the Southwest during the last ice age,” said Cole. “When it was cold in Greenland, it was wet here, and when it was warm in Greenland, it was dry here.”

The researchers studied natural climate archives recorded in a stalagmite in a limestone cave in southern Arizona.

Cole said the stalagmite yielded a nearly continuous, century-by-century climate record spanning 55,000 to 11,000 years ago. During that time ice sheets covered much of North America and the U.S. Southwest was cooler and wetter than it is now.

Cole and her colleagues found the Southwest alternated between wet and dry periods during the period studied, with each climate regime lasting from a few hundred years to more than 1,000 years.

“These changes are part of a global pattern of abrupt changes that were first documented in Greenland ice cores,” she said. “No one had documented those changes in the Southwest before.”

The research that included co-author Gideon Henderson of Britain’s University of Oxford is to appear in the February issue of the journal Nature Geoscience.

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