A new satellite study of world temperatures over the past decade has found no evidence of the global warming trend predicted by many scientists.
The new finding reported Thursday is certain to fire up the debate in the scientific community over whether world temperatures are actually on the rise.The latest report on global temperature trends is said by its authors, a team of researchers from the National Aeronautics and Space Administration and the University of Alabama in Huntsville, to be the most reliable yet prepared.
It relies on data gathered from 1979 through 1988 by a series of satellites launched into the upper atmosphere in late 1978 by the Commerce Department's National Oceanic and Atmospheric Administration.
"There is no warming for those years," said John Christy of the University of Alabama's Johnson Research Center.
While earth-based measurement systems and a variety of mathematical models of global climate change used by other researchers have concluded previously that there was a global warming of about a half degree over those 10 years, "we see basically nothing," Christy said in a telephone interview.
The government satellites were equipped with devices able to measure the temperature in a layer of air 600 miles wide and 5,000 feet to 20,000 feet above sea level, a slice of the upper atmosphere where scientists predict the first telltale signs of global warming will appear.
Surprisingly, instead of a steady warming trend, the researchers found a seemingly random pattern of change from year to year.
"The warmest year was 1987, and the next warmest was 1988, but the average of the first five years - 1979 to 1983 - was warmer than the most recent five," Christy said.
The years 1984, 1985 and 1986 were the coolest of the decade, Christy and colleague Roy Spencer of NASA said.
Their report is published in this week's Science magazine.
The two men said they found the satellite-based system for gathering temperature data to be far more accurate than any earth-based system.