Warming Arctic increases odds of prolonged drought

Currently, temperatures at northern high latitudes are increasing at rates double the national average.

By Brooks Hays

March 28 (UPI) -- As the Arctic continues to warm, new research suggests the odds of a prolonged drought increase.

At the end of the last ice age, some 10,000 years ago, rising Arctic temperatures encouraged drought conditions throughout the mid-latitudes. According to a new study, history is likely to repeat itself.


"Our analysis shows that, when the Arctic is warmer, the jet stream and other wind patterns tend to be weaker," Bryan Shuman, a professor of geology and geophysics at the University of Wyoming, said in a news release. "The temperature difference in the Arctic and the tropics is less steep. The change brings less precipitation to the mid-latitudes."

Currently, temperatures at northern high latitudes are increasing at rates double the national average.

At the end of the last ice age, similar temperature patterns emerged. Researchers analyzed 236 samples of sediments from 219 sites at three Wyoming lakes.

"Lakes are these natural recorders of wet and dry conditions," Shuman said. "When lakes rise or lower, it leaves geological evidence behind."

Most of the region's lakes were lower several thousand years ago than they are today. In fact, large swaths of what's now the United States were comparatively dry during the early Holocene, the epoch that began 12,000 years ago.


"Wyoming had several thousand years where a number of lakes dried up, and sand dunes were active where they now have vegetation," Shuman said. "Expanding to the East Coast, it is a wet landscape today. But 10,000 years ago, the East Coast was nearly as dry as the Great Plains."

The comparison of polar temperature records to drought records in Wyoming showed precipitation levels dropped as the Arctic warmed. According to Shuman and his colleagues, the new analysis -- published this week in the journal Nature -- will improve the predictions of today's climate models.

"This information creates a test for climate models," Shuman said. "If you want to use a computer to make a forecast of the future, then it's useful to test that computer's ability to make a forecast for some other time period. The geological evidence provides an excellent test."

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