"Satellite Data Sheds New Light on Solar Cycle"

"The sun may warm the Earth more during waning solar cycles, new satellite data has shown, turning scientific understanding on its head and helping to explain extreme local weather patterns, scientists said on Wednesday.

But scientists said the findings did not undermine the case for man-made global warming through greenhouse gas emissions.

The heat and light of the sun waxes and wanes over a roughly 11-year period. Scientists had thought it warmed the Earth more during peaks of activity, for example as measured by the number of spots visible in the sun's atmosphere.

But new satellite data showed that, in fact, from 2004-2007 as the cycle waned, more light reached the Earth's surface. It was only high frequency, ultraviolet light -- which hardly reaches the Earth's surface -- that faded.

That means the sun warmed the Earth more during that declining cycle, a new and counter-intuitive finding."

Gerard Wynn reports for Reuters October 6, 2010.