Sandia Labs News Releases

Climate change accelerating Southwest desertification, speaker says

ALBUQUERQUE, NM — Jonathan Overpeck, professor of Atmospheric Sciences and Geosciences at the University of Arizona, brought a friendly smile, informative graphics and a warning about drought in the Southwest to Sandia’s Climate Change and National Security Speaker Series.

Addressing “Climate Change and the Aridification of the North American Southwest and Beyond,” Overpeck placed water-glass graphic images at key water-storage locations in the Southwest to show how full the reservoirs are.

Many glasses are more than half-empty, he said, and computer simulations predict the situation will worsen.

Overpeck has authored more than 150 published papers in climate and environmental sciences. He was coordinating lead author for the Nobel Prize-winning U.N. Intergovernmental Panel on Climate Change (fourth assessment).

In an effort to shed light on the wide spectrum of thought regarding the causes and extent of changes in Earth’s climate, Sandia National Laboratories has invited experts from a wide variety of perspectives to present their views in the Climate Change and National Security Speaker Series.

Overpeck recounted unprecedented heat waves that included a growing number of days above 110 degrees in Phoenix and the 840-square-mile Wallow Fire last May, the biggest wildfire ever in New Mexico and Arizona. He pointed to major floods that, by National Oceanic and Atmospheric Administration estimates, have caused $53 billion in damages. He also mentioned a record tornado season and an unusually wet and destructive tropical storm.

“The temperature record for March 2012 (8.6 degrees above the 20th century average for that month) was big news,” he said.

But the major problem facing the Southwest, he said, is drought. Water managers are used to dry years with occasional wet years, he said. “How would you adapt to a 51-year drought?” such as what Native Americans apparently faced nearly a thousand years ago in roughly the same locale, he asked.

Even now, water storage in many reservoirs is below average, he said, and southwestern river systems are over-allocated. The warmer the weather, the greater the impact of drought, and the weather is getting warmer, Overpeck said.

“More greenhouse gases mean less snow, drier soils, less late winter snow and rain, less water in rivers, along with more flooding and more frequent and severe droughts,” he said. “The mega-drought risk is substantial.”

However, Overpeck said, “the climate challenge also includes opportunities,” including a societal “no-regrets adaptation” to heat and drought, more efficient renewable energy technology, climate change mitigation that would mean cleaner air and improved health and new technologies to secure supplies of clean water.

In a dig at conventional power sources, he said, “It’s depressing to sit at Four Corners and look at Shiprock. Sometimes you can hardly see the thing, the air there is so nasty.”

Still, he concluded, “We can’t conserve our way out of this problem.”

The climate talks are sponsored by Sandia’s Climate Security Program.

Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin company, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies and economic competitiveness.

Sandia news media contact: Neal Singer,, (505) 845-7078