Arnold Schwarzenegger has a new role: Activist

PASADENA, Calif. — Arnold Schwarzenegger is tackling his newest role: Climate change activist.

The movie star and former governor is one of many celebrities taking part in Years of Living Dangerously, a Showtime documentary that will air in April. He became interested in global warming during his stint as governor of California - and grew concerned that the message wasn't getting through to the public in the way he thought it should.

"I always felt that there was a communications gap and a communications problem around the subject of global warming, to bring ordinary people in and make them part of the movement." What the movement needed, he said, was a clearer message – and better messengers than scientists.

Enter Years of Living Dangerously, which approaches the issue of global warming from the effect it's having on ordinary people – and uses celebrities to introduce us to the people affected. Among those joining Schwarzenegger are Harrison Ford, Matt Damon, Jessica Alba and Vampire Diaries' Ian Somerhalder.

"You want to get to the human quality of it," says Somerhalder, "and if you want eyeballs, you have to go to television….I'm just leveraging the access that a vampire TV show gives me, but through that access comes activation."