Warming felt more in Western U.S.

An analysis of 50 studies finds that the region's temperatures are increasing faster than in the rest of the country and the planet as a whole.

By Margot Roosevelt
Los Angeles Times Staff Writer

March 28, 2008

The American West is heating up faster than any other region of the United States, and more than the Earth as a whole, according to a new analysis of 50 scientific studies.

For the last five years, from 2003 through 2007, the global climate averaged 1 degree Fahrenheit warmer than its 20th century average.

During the same period, 11 Western states averaged 1.7 degrees warmer, the analysis reported.

The 54-page study, "Hotter and Drier: The West's Changed Climate," was released Thursday by the Rocky Mountain Climate Organization -- a coalition of local governments, businesses and nonprofits. It was based largely on calculations by the National Oceanic and Atmospheric Administration.

The report reveals "the growing consensus among scientists who study the West that climate change is no longer an abstraction," said Bradley H. Udall of the University of Colorado, whose work was cited in the study. "The signs are everywhere."

Carbon dioxide pollution from vehicles, power plants and other industrial sources is a major contributor to global warming. The Environmental Protection Agency is under court order to address cutting greenhouse gases, and Congress is considering legislation to curb them.

The consequences of Western temperature increases, the report said, are evident in a rash of heat waves. Montana, Idaho and Wyoming had their hottest Julys on record last summer, while Phoenix suffered 31 days above 110 degrees.

Likely to accelerate

The Colorado River basin, which stretches from Wyoming to Mexico, is in the throes of a record drought. About 30 million people in fast-growing cities such as Los Angeles, San Diego, Phoenix and Las Vegas depend on water from the Colorado and its tributaries, which also drive the region's agricultural economy and hydroelectric industry. The river's two main reservoirs, Lake Powell and Lake Mead, are only 45% and 50% full, respectively.

Globally, warming varies according to region -- with more heating over land than over oceans. In California, with its coastal location, the study showed an increase of 1.1 degrees above the global average over the last five years. Arid interior states, including Utah, Wyoming, Arizona and Montana, experienced rises more than 2 degrees higher than in the world overall.

"Temperature rises have been much larger and more noticeable in the Western states," said Kelly T. Redmond, regional climatologist at Nevada's Desert Research Institute. "The past 10 years have been particularly warm, unlike any similar 10-year period we have seen over the past 115 years."

According to Udall, the data suggest that the trend will accelerate -- with the West warming about 1 1/2 times faster than the global average. Martin Hoerling, a NOAA meteorologist, has predicted that the West could heat up as much as 5 degrees by mid-century. In Alaska, the annual mean air temperature has risen 4 to 5 degrees Fahrenheit over the last three decades.

"If we don't want this problem to get really bad, we need to pass a climate bill with teeth," said Theo Spencer, a project manager at the Natural Resources Defense Council, an environmental advocacy group that funded the Rocky Mountain Climate analysis. "Western senators need to take the lead, considering what's at stake in their states."

Legislation in the works

A bill to slash greenhouse gases nationwide, sponsored by Sens. Joe Lieberman (I-Conn.) and John W. Warner (R-Va.), is expected to reach the Senate floor by June. A recent tally by the newsletter Environment & Energy Daily counted 44 votes for the bill so far.

As many as 10 Republican senators from Western states are leaning against the bill, according to the newsletter, which based its research on interviews with lawmakers, staff, industry and environmental groups.

California's two senators, Democrats Barbara Boxer and Dianne Feinstein, favor the bill.

In the absence of federal action, states are moving ahead. California is drafting rules to slash its greenhouse gas emissions by 80% by mid-century. And six other Western states -- Arizona, Montana, New Mexico, Oregon, Utah and Washington -- have joined it in a regional compact to curb the pollution blamed for global warming.