Tuesday, December 14, 2010

Drought Warmest in 1,000 Years

By John Fleck
Journal Staff Writer
The drought of the last decade in the Southwestern United States is likely the warmest in more than a thousand years, new research suggests.
The warm, dry weather is consistent with predictions of the effect of rising greenhouse gases, but scientists cannot rule out natural variability as the cause, according to work by a team of scientists published Monday in a special edition of the Proceedings of the National Academy of Sciences.
But while there remains some uncertainty about whether human-caused climate change is responsible for the current drought, greenhouse warming caused by fossil fuel emissions appears likely to create problems in the future, the scientists said.
“We are on the path toward abnormal warming,” said Park Williams of the University of California Santa Barbara.
Even without warming, we are using our water unsustainably, said University of California Los Angeles scientist Glen MacDonald, who led the team of scientists.
“We have a supply and demand issue no matter what,” MacDonald said in a telephone interview.
The drought has hit New Mexico’s two major river basins hard.
Flows on the Rio Grande from 2000 to 2009 averaged just 77 percent of normal. The Colorado River, which New Mexico shares with six other Western states, has experienced the driest decade since record-keeping began a century ago.
Using tree rings, the scientists tried to find a period in the past that was similar to the current drought, said Connie Woodhouse of the University of Arizona. Looking back across the last 1,200 years, they were able to find longer dry spells, Woodhouse said, but none is as warm as conditions today, she said.
“We probably have not had as hot a drought,” said MacDonald.
The West’s forests have already suffered, according to Williams. Some 18 percent of the forests experienced either wildfires or bark beetle infestations.
Projected warming and drying is likely to make that worse, Williams said in a phone interview.
Growing population and rising food demand will place increasing stress on the region’s water supplies, MacDonald said.
With little chance to develop additional supplies, life in the West going forward will require new approaches to how we use water in our cities, especially for outdoor landscaping, MacDonald said.
We also will need to rethink our approach to agriculture, which uses 80 percent of the region’s supply, according to MacDonald.

Read more: ABQJOURNAL NEWS/STATE: Drought Warmest in 1,000 Years http://www.abqjournal.com/news/state/14232467836newsstate12-14-10.htm#ixzz18JdMW4oN
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