Mark Ruffalo the ‘Accidental Environmentalist’

Getty ImagesActor Mark Ruffalo isn't about to let his fame go to waste.

"I have a voice that just happens to go farther than some people's," he says, "and so I have a responsibility to use that to talk about the things that I think are important."

One of those things is climate change. But it wasn't always. "The Kids Are All Right" star admits to being "an accidental environmentalist." Sure, he'd always thought of himself as environmentally conscious, but he used to contribute to causes simply by writing checks. Then something changed for the 43-year-old, who lives on an Upstate New York farm with his wife and three children.

"I saw this mass industrialization of Upstate New York and Pennsylvania for hydraulic fracturing [a process known as"fracking," which breaks apart rock to release natural gas]. And that sort of opened my eyes," he says.

Now Ruffalo has joined other celebs including Adrian Grenier, Orlando Bloom, Serena Williams, and Kyra Sedgwick to support the non-profit Global Green USA's "I Am" campaign to bring attention to the coastal cities that are most threatened by sea level rise caused by global warming.

Watch Global Green's 'I Am' Video Featuring Mark Ruffalo

Despite the fact that this particular cause has the backing of a handful of celebrities, Ruffalo believes there are more famous folks out there who want to speak out on certain issues, but don't.

Mark, pictured here with Global Green's president and CEO Matt Petersen, is part of the group's "I Am" campaign …

"A lot of actors either don't feel it's their business or their place or they're frightened to come out because there's such a strong, I'd say right wing attack machine in place that's ready to hop on anybody who takes a point of view that's ideologically not in line with those beliefs," he admits. "I think a very cynical group of people have done much to marginalize the voice of celebrities and artists in general. That particular group, which was historically significant [and] that generally tended to serve the common good, that's been quelled."

Slowly, however, Ruffalo says he's seeing more average Americans -- even in the heavily conservative Upstate New York town where he lives -- paying more attention to global warming, in part, he explains, because the area has experienced a 50-year flood, 100-year flood, 200-year flood, and a500-year flood ... all in the last five years, not to mention the droughts, hurricanes, and tornadoes around the country.

"For a long time [fellow residents] would, you know, make fun of me good humoredly. It was, you know, 15 below zero and [they'd ask]' How's your global warming there?'," the actor recalls. "And those same people are now scratching their heads. I mean these are old timers ... who watched the weather and seasons and changes, and they're farmers. And they see a radical change happening and I hear them wondering if its global warming."

Though Ruffalo has appeared on a few cable news programs over the years to talk about environmentalism, he insists he has no designs on becoming a politician. "I'm not interested in politics per se as inrunning for office. I am interested in a better, more civil world."

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