From an article by Richard Monastersky in Science News (Jan. 19):

Planet Earth steamed straight into the 1990s with record-setting temperatures that extended the warming trend of the last two decades. In separate statements released last week, two groups of researchers reported that the global average surface temperature during 1990 was the highest in more than a century of weather measurements.

While most climate experts say they cannot tell whether the warming trend results from the buildup of greenhouse gases, some display an increasing willingness to draw suggestive connections. "Although it is still too early to confirm whether the recent exceptional warmth is related to the greenhouse effect, international scientific opinion strongly supports the reality of this enhanced greenhouse effect, and it is likely it has played some role in contributing to the recent warmth," asserts a group of British scientists who monitor global records of land and marine temperatures. . . .

{Team member Phil} Jones, of the University of East Anglia in Norwich, and his colleagues report that six of the seven warmest years in their 140-year-long record have occurred since 1980. And researchers who have analyzed land-station data at NASA's Goddard Institute of Space Studies in New York City say the century-plus record occurred since 1980. Both groups find a 0.5 C warming over the last century. . . .

Measurements from balloons indicate that the troposphere -- the lowest part of the atmosphere -- has also warmed recently, says James K. Angell of the National Oceanic and Atmospheric Administration in Silver Spring, Md. In the 23-year record of tropospheric temperatures, 1988 and 1990 share first place.