From the BBC:

A new scientific study concludes that changes in the Sun's output cannot be causing modern-day climate change.

It shows that for the last 20 years, the Sun's output has declined, yet temperatures on Earth have risen.

It also shows that modern temperatures are not determined by the Sun's effect on cosmic rays, as has been claimed.

Writing in the Royal Society's journal Proceedings A, the researchers say cosmic rays may have affected climate in the past, but not the present.

"This should settle the debate," said Mike Lockwood from the UK's Rutherford-Appleton Laboratory, who carried out the new analysis together with Claus Froehlich from the World Radiation Center in Switzerland.