Prehistoric Dust Bowls Occurred in US

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DURHAM, NC, Aug. 2 (UPI) -- A multi-institutional research team led by Duke University has determined prehistoric droughts occurred in the northern U.S. Great Plains.

The researchers say each of the ancient droughts persisted for as long as several decades and some lasted a century or more.
"We were looking for the effects of past climate changes on ecosystems," reported Jim Clark of Duke's Nicholas School of the Environment and Earth Sciences.

Said Clark: "What would happen was that the grass would disappear. So the fuel for fire would be lost. We'd see the erosion start. The chemistry of the lakes would change. We would see these dust-bowl effects. And then, within several decades to a century later, the grasses would come back, fires would start back up and erosion would stop."

Clark said researchers found very coherent drought cycles of about once each decade.

The study will be presented at the Oregon Convention Center during the Ecological Society of America's 2004 annual meeting in Portland Wednesday.

For more information, contact Tim Lucas in the Nicholas School’s Office of Communications at (919) 613-8084 or tdlucas@duke.edu.