ENVIRONMENT : Greenhouse Effect Questioned

Despite fears that the greenhouse effect is heating up Earth’s atmosphere, temperature measurements taken by satellites show the planet has not warmed over the past decade, scientists reported today.

Researchers from NASA’s Marshall Space Flight Center and the University of Alabama in Huntsville said they found dramatic swings in monthly and yearly temperature patterns, but the average global temperature did not rise--or fall--in the 10-year period from 1979 through 1988.

“There is no obvious long-term trend, and anomalies (variations) during the first five years nearly balance those during the last five years,” researchers Roy Spencer and John Christy wrote in a study published in the journal Science.

The scientists emphasized their findings go back only as far as 1979, and cannot be used to determine whether Earth has actually warmed about 1 degree Fahrenheit over the past century as most ground-based records show.

Many scientists have blamed the reported global warming over the past 100 years on the greenhouse effect, which is caused by higher emissions of carbon dioxide and other gases produced by fuel burning and clearing of forests. The gases act like a greenhouse by trapping energy in the atmosphere.