A new drought scare
As the authors below implicitly admit, a warmer ocean should in general create MORE rain, not less, but in good Greenie style they want us to have the worst of all possible worlds so they purport to show that we could have drought and warming too. Whether their claims about past drought are correct, however, depends on how good their proxies are -- and after the need to "hide the decline" shown in tree-ring proxies, we must be thoroughly skeptical about that
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.
"We're not saying future droughts will be worse than what we see in the paleo record, but we are saying they could be as bad," said lead author Connie A. Woodhouse, a UA associate professor of geography and regional development. "However, the effects of such a worst-case drought, were it to recur in the future, would be greatly intensified by even warmer temperatures."
The team's paper is part of the special feature, "Climate Change and Water in Southwestern North America," scheduled for publication Dec. 13 in the Early Online edition of the Proceedings of the National Academy of Sciences.
The paper by Woodhouse and her colleagues is titled, "A 1,200‑year perspective of 21st century drought in the southwestern North America." Co‑authors are Glen M. MacDonald of the University of California, Los Angeles; Dave W. Stahle of the University of Arkansas in Fayetteville; and Edward R. Cook of Lamont‑Doherty Earth Observatory of Columbia University, Palisades, N.Y....
The most severe warm-climate drought in the Southwest within the last 1,200 years was 60 years long and occurred during the mid-12th century, according to research by Meko and others. That drought covered most of the western U.S. and northern Mexico.
For a 25-year period during that drought, Colorado River flow averaged 15 percent below normal, according to the tree-ring-based reconstruction of stream flow at Lees Ferry....
"Even without warming, if you had one of those medieval droughts now, the impact would be devastating," she said. "Our water systems are not built to sustain us through that length of drought."
In addition, other research predicts that changes in atmospheric circulation will reduce the amount of winter precipitation the Southwest receives in the future, she said. "The bottom line is, we could have a Medieval-style drought with even warmer temperatures," Woodhouse said.