CLIMATE

Rising Sun

Humans may be shouldering too much of the blame for global warming, according to a new look at data from six sun-gazing satellites. They suggest that Planet Earth has been drenched in a bath of solar radiation that has been intensifying over the past 24 years--an increase of about 0.05 percent each decade. If that trend began early last century, it could account for a significant component of the climatic warm-up that is typically attributed to human-made greenhouse gases, says Richard C. Willson of Columbia University's Center for Climate Systems Research in Coronado, Calif. Willson concedes that the climate's sensitivity to such subtle solar changes is still poorly understood, but the evidence merits keeping a close eye on both the sun and humans to better gauge their relative influences on global climate. "In 100 years I think we'll find the sun is in control," he says. His team's report appears in the March 4 Geophysical Research Letters. --Sarah Simpson

   
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