A team of government scientists has concluded after examining temperature and rainfall records going back nearly 100 years that there is no evidence of significant warming or changes in precipitation in the contiguous United States.
Nor are there any indications in the weather records so far to substantiate some global warming models that suggest that the "greenhouse effect" will result in drier summers and wetter winters in the central regions of the continent, the scientists said.
"The most important result of this study is that there is no statistically significant evidence of an overall increase in annual temperature or change in annual precipitation for the contiguous U.S. (between) 1895 and 1987," they concluded.
While the scientists said their study should not be interpreted as debunking the greenhouse effect, it appeared certain to add to a growing scientific controversy over when and where the postulated global warming would take place.
"We're not saying this makes the greenhouse effect go away. I'm personally concerned about the greenhouse effect," climate research scientist Kirby Hanson said in a telephone interview from Miami.
The findings, published in the January issue of the American Geophysical Union's Geophysical Research Letters, were the result of research by three scientists with the National Oceanic and Atmospheric Administration. The co-authors of the study were George A. Maul and Thomas R. Karl.
Last July in the midst of a scorching heat wave and drought in the Midwest, James Hansen of the National Aeronautics and Space Administration's Goddard Institute startled members of Congress when he testified that the unusually hot conditions could be the forerunners of the long-feared greenhouse phenomenon.
Global Readings
Hansen had previously examined temperature readings from around the globe going back 100 years. On the basis of detailed studies, Hansen concluded that global temperatures had risen about 0.6 degrees Celsius (about one degree Fahrenheit) during the last century. He said that figure was "consistent with" though slightly lower than temperatures predicted by greenhouse computer models. He could not be reached for comment Wednesday.
Largely based on Hansen's testimony, there has been a flurry of legislation introduced in Congress and the California Legislature calling for new restrictions on emissions of gases such as carbon dioxide, chlorofluorocarbons and methane in order to slow down global warming.
