Irrigation Blamed for Warming San Joaquin
FRESNO, Calif. - Global warming from carbon dioxide emissions may not be to blame for rising nighttime temperatures in the San Joaquin Valley, according to a study funded by the National Science Foundation.
John Christy, director of the Earth System Science Center at the University of Alabama in Huntsville, said rising valley temperatures may be caused by an overabundance of irrigated land that increases humidity in the air.
Nighttime temperatures in the study's six-county region - Fresno, Kings, Madera, Mariposa, Merced and Tulare - have risen more than four degrees Fahrenheit over seven decades, said Christy, who is leading the three-year study.
"One of the big issues right now is human-induced climate change from carbon dioxide," Christy said Monday. "Actually, it appears temperature change in the valley could be due to a different human factor, and that is irrigation."
California has more than eight million irrigated acres, some two million of which are in the study's five-county region.
Christy's preliminary data conflicts with global warming theories suggesting carbon dioxide is the cause of rising temperatures. His data suggests increased humidity in the valley is preventing nighttime air from cooling.
"The evidence shows that if this were a large scale climate change caused by carbon dioxide, it would affect the valley, the foothills and the mountains. But we have not seen these changes in the higher elevations," Christy said.
Dave Kranz, a California Farm Bureau spokesman, questioned Christy's data.
"Is it irrigation that's adding to warming temperatures or is it sunlight reflecting off all the paved roads that come with urbanization?" Kranz said.
He said Christy's theories seem somewhat flawed.
"The crops that are grown on irrigated land actually help clean the air," Kranz said. "For example, it's estimated that each acre of rice in California scrubs about 23,000 pounds of carbon dioxide from the atmosphere."
ON THE NET
National Science Foundation: http://www.nsf.gov
RENO, Nev. (AP) - The U.S. government has identified 35 sites in the West as having the greatest potential for quick development of geothermal power.
In issuing the study, officials acknowledged that the energy alternative, which uses superheated water from below the earth's surface to power generators, has been neglected for the past decade.
Ten sites in Nevada, nine in California and seven in Oregon are among those the Interior and Energy departments identified as holding the most immediate promise, federal officials said Monday. New Mexico, Utah and Washington each have three sites.
The study is the result of an increased emphasis on geothermal potential on federal lands - primarily Western lands managed by the Bureau of Land Management. It's part of an effort to reduce U.S. dependency on foreign energy, said Rebecca Watson, assistant interior secretary for land and minerals management.
Forty-eight percent of all geothermal power produced in the United States comes from federal lands, Watson said, and the new review concentrates on six states believed to have the most potential in the West.
Two-thirds of the 35 priority sites have been reviewed or are at
some stage of environmental analysis.
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