Addressing a largely student audience at Georgetown University in Washington, D.C., the Republican governor said he was optimistic attitudes to the environment were changing, but campaigners on climate change still need to shake their image as “tree-huggers” and “fanatics.”

“Successful movements aren’t built on guilt, they are built on passion,” he said.

He believes the environmental movement is approaching a “tipping point” where it will enter the mainstream, galvanizing business and individuals. Many see California as leader in tackling climate change in the US. The state – the sixth largest economy in the world – signed a law last year to cut greenhouse gas emissions by 25% by 2020.

And while Schwarzenegger cannot stand for president in 2008 because he is not US-born, he has said he wants his views on climate change to play into the race.

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