LITTLE ROCK, Ark., Oct. 8 (UPI) -- A group studying tree rings in western North America say historical climate patterns show the region could be in for a long dry spell.
"The data show that the 20th century has been relatively wet, despite the drought calamities that have befallen us," said David Stahle, professor of geosciences at the University of Arkansas.
The group examined the patterns from 602 trees, getting hints about climate in the area going back 1,200 years. Researchers found that the American West suffered from severe drought between 900 and 1300 AD, a period that was warm in Europe.
Since 1920, rainfall has been slowly decreasing, Stahle said, to the point where much of the region is dryer than it has been for hundreds of years. But he said the drought is still not as severe as the medieval one.
If there is a link between warm weather and western drought, global warming could put enormous pressure on the region, Stahle said.
