US southwest could see 60-year drought: study
Annual tree rings record a detailed history of drought (narrow rings) and wetness (wide rings). This sample from a dead Douglas-fir tree in the Santa Catalina Mountains near Tucson, Ariz., has nearly 400 rings and dates back to the year 1600. Stress cracks, visible in the foreground of the image, occur as the dead wood dries and contracts. Credit: Copyright Daniel Griffin.
An unprecedented combination of heat plus decades of drought could be in store for the Southwest sometime this century, suggests new research from a University of Arizona-led team.
To come to this conclusion, the team reviewed previous studies that document the region's past temperatures and droughts.
"Major 20th century droughts pale in comparison to droughts documented in paleoclimatic records over the past two millennia," the researchers wrote. During the Medieval period, elevated temperatures coincided with lengthy and widespread droughts.
By figuring out when and for how long drought and warm temperatures coincided in the past, the team identified plausible worst-case scenarios for the future. Such scenarios can help water and other resource managers plan for the future, the team wrote.
http://www.physorg.com/news/2010-12-hot-decades-drought-southwest.html