The American West is heating up more rapidly than the rest of the world, according to a new analysis of the most recent federal government temperature figures. The news is especially bad for some of the nation's fastest growing cities, which receive water from the drought-stricken Colorado River. The average temperature rise in the Southwest's largest river basin was more than double the average global increase, likely spelling even more parched conditions.

Colorado River, Utah
©iStockphoto/Eric Foltz
Colorado River, Utah. The West's most pronounced temperature increase is in the Colorado River basin, which has warmed more than twice as much as the global average, with effects that put at risk a major water supply.

"Global warming is hitting the West hard," said Theo Spencer of the Natural Resources Defense Council (NRDC). "It is already taking an economic toll on the region's tourism, recreation, skiing, hunting and fishing activities. The speed of warming and mounting economic damage make clear the urgent need to limit global warming pollution."

For the report, the Rocky Mountain Climate Organization (RMCO) analyzed new temperature data from the National Oceanic and Atmospheric Administration (NOAA) for 11 western states. For the five-year period 2003-2007 the average temperature in the Colorado River Basin, which stretches from Wyoming to Mexico, was 2.2 degrees Fahrenheit hotter than the historical average for the 20th Century. The temperature rise was more than twice the global average increase of 1.0 degree during the same period. The average temperature increased 1.7 degrees in the entire 11-state western region.

"We are seeing signs of the economic impacts throughout the West," said study author Stephen Saunders of the Rocky Mountain Climate Organization. "Since 2000 we have seen $2.7 billion in crop loss claims due to drought. Global warming is harming valuable commercial salmon fisheries, reducing hunting activity and revenues, and threatening shorter and less profitable seasons for ski resorts."

The Colorado River Basin is in the throes of a record drought, shrinking water supplies for upwards of 30 million people in fast-growing Denver, Albuquerque, Las Vegas, Phoenix, Los Angeles and San Diego. Most of the Colorado River's flow comes from melting snow in the mountains of Wyoming, Utah and Wyoming. Climate scientists predict even more and drier droughts in the future as hotter temperatures reduce the snowpack and increase evaporation.

To date, the governors of Arizona, California, Montana, New Mexico, Oregon, Utah and Washington have signed the Western Climate Initiative (WCI), an agreement to reduce global warming pollution through a market-based system, such as cap-and-trade. The WCI calls for states to reduce their global warming emissions 15 percent below 2005 levels by 2020. Conservationists say the states should commit to meeting these targets, and that there should also be a firm target of an 80 percent reduction by 2050.

A growing chorus of leaders across the political and economic spectrum says more aggressive action is needed at the national level. Supporters say the Lieberman-Warner bill, "America's Climate Security Act" (S. 2191), is the strongest global warming bill moving through Congress. The bipartisan bill is the first climate legislation ever to be passed out of a Senate committee. The full Senate is expected to vote on the bill by summer, by which time supporters are optimistic about strengthening the bill even further.

"We need strong leadership from western senators to pass America's Climate Security Act," said Spencer. "The longer we wait to put a concrete cap on global warming pollution, the greater the threat to all Americans."

The NRDC-RMCO report, "Warming in the West," analyzed temperature data from Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming. The report is available HERE: .

Adapted from materials provided by Natural Resources Defense Council.