Greenhouse warming was main cause of U.S. warmth last year, study says

Associated Press
August 28, 2007

WASHINGTON — "We have met the enemy, and he is us," the comic-strip character Pogo said decades ago. A new analysis of last year's near-record temperatures in the United States suggests he was right.

Warming caused by human activity was the biggest factor in the high temperatures recorded in 2006, according to a report by researchers at the National Oceanic and Atmospheric Administration.

The analysis, released Tuesday, is being published in the September issue of Geophysical Research Letters, published by the American Geophysical Union.

In January, NOAA's National Climatic Data Center reported that 2006 was the warmest year on record over the 48 contiguous states with an average temperature 2.1 degrees Fahrenheit warmer than normal and 0.07 degree warmer than 1998, the previous warmest year on record.

In May, however, NOAA revised the 2006 ranking to the second warmest year after updated statistics showed the year was actually .08 F cooler than 1998.

They ran 42 different tests using complex computer models to simulate changes in the atmosphere under various conditions and concluded that the "2006 warmth was primarily due to human influences."

While Hoerling's study focused on the United States, NOAA also tracks world climate. Worldwide, 2005 was the warmest year on record, topping 1998, according to the agency.

The research was supported by NOAA's office of Global Programs.