Global Warming - Alternative Theory

In the past I have discussed how it is possible that increased solar activity could be responsible for global warming. (See here) a Timesonline (London) piece written by Tim Hames that discusses this possibility in a reasonable and rational manner.

Tim Hames reports:

In 2003 a team from Columbia University reported that the Sun's heat had increased by 0.05 per cent a decade since the 1970s, the point when completely reliable data started to be collected. This would be enough to have a big influence on the Earth's climate if it were a trend that had continued for many decades. The Columbia team believed that the pattern could be traced back to the mid-19th century at the very least. Others, working with carbon data material, insist that the Sun has been more vigorous in the past six decades than at any time in 8,000 years.

I have also heard a discussion on PBS (Public Broadcasting Service) where it was put forth that as recently as 5,000 years ago much of America's Great Plains were desert due to lack of rainfall for a prolonged period of time. Certainly our understanding of our planet's history includes massive climate fluctuations that can not be blamed on human activity. I for one am still going to be open to arguments that something besides greenhouse gases could explain the obvious global warming we are experiencing. I am grateful that next month (as Tim Hames reports) NASA will launch the Solar Terrestrial Relations Observatory (Stereo) that could aid us in exploring whether increased solar activity is the true culprit behind global warming.