The Sun and Global Warming

This is an article that I found to be fascinating regarding the debate on whether the sun is the primary cause of global warming. It is fairly lengthy but easily readable.

Sun and global warming: A cosmic connection?

By Richard Black
Environment correspondent, BBC News website

In February 2007, depending on what newspaper you read, you might have seen an article detailing a "controversial new theory" of global warming.

The idea was that variations in cosmic rays penetrating the Earth's atmosphere would change the amount of cloud cover, in turn changing our planet's reflectivity, and so the temperature at its surface.

This, it was said, could be the reason why temperatures have been seen to be varying so much over the Earth's history, and why they are rising now.

The theory was detailed in a book, The Chilling Stars, written by Danish scientist Henrik Svensmark and British science writer Nigel Calder, which appeared on the shelves a week after the Intergovernmental Panel on Climate Change (IPCC) had published its landmark report concluding it was more than 90% likely that...(complete article here).

I think the conclusion here is that there are many theories concerning climate change floating around. Ultimately, we don't know with certainty what is causing the current warming trend. All we have today are theories and models.