Alternative climate-change theory.(Inside Track)(Brief article)

For the last decade, scientist Henrik Svensmark of the Danish Space Research Institute and his collaborators have been piecing together evidence supporting a novel theory that may spark a paradigm shift in how climate change is understood. According to Svensmark, the key to understanding the Earth's climate does not lie with human release of greenhouse gases, but can actually be found among the stars.

In a 1999 paper entitled "Cosmic Rays and the Earth's Climate," Svensmark discussed the impact of "galactic cosmic rays" (GCR) on climate. "Recently it was found that the Earth's cloud cover, observed by satellites, is strongly correlated with GCR," he wrote, noting that galactic cosmic rays play a role in cloud formation. According to Svensmark, when the sun is in a more active state (as it has been in recent years), solar influences deflect a greater amount of cosmic radiation, causing a reduction in cloud cover that allows more solar radiation to penetrate and heat the atmosphere. Periods of low solar activity lead to the opposite ...