"Bush aide says warming man-made"

The US chief scientist has told the BBC that climate change is now a fact. (That's big of him)

Professor John Marburger, who advises President Bush, said it was more than 90% certain that greenhouse gas emissions from mankind are to blame.

The Earth may become "unliveable" without cuts in CO2 output, he said, but he labelled targets for curbing temperature rise as "arbitrary"...