The celebrity power fueling “Years of Living Dangerously,” Showtime’s multipart, James Cameron-Arnold Schwarzenegger-Jerry Weintraub-produced documentary devoted to sounding alarms about climate change, is inevitably a double-edged sword. Big-name stars obviously call attention to a project that otherwise might be lost in the shuffle, but they also make it easy for deniers to dismiss the message because of the messengers (oh those silly tree-hugging Hollywood dilettantes — though Schwarzenegger has right-wing street cred as a recent Republican governor). Nevertheless, this is a serious look at an important issue, and the fact its talking heads could just as easily be working on “Ocean’s 14” or “The Expendables 3” shouldn’t be held against it.

Indeed, the actors who participate in the first few episodes at least put their money (that is, their time) where their mouths are, traveling to far-flung locales with camera crews in tow to investigate what’s happening and discuss possible solutions. And while they’re not journalists (with the exception of New York Times columnist Tom Friedman), they do exhibit a facility for asking the right questions.

“Is there a way to discuss climate change,” Don Cheadle asks, as he ventures deep into the God-fearin’, science-hatin’ heart of Texas, “without politics or religion getting in the way?”

The answer’s probably “no,” based on the tenor of the debate, but that doesn’t dissuade the participants in “Living Dangerously” from dutifully plowing ahead: Harrison Ford exploring deforestation in Indonesia; Cheadle meeting with a scientist who happens to be a devout Christian; Schwarzenegger wondering about a fire season in California and the Western U.S. that “seemed to last all year,” and going to the front lines with a group of firefighters.

The statistics used are occasionally mind-boggling (enough forest lost every year to cover Germany), and the stars’ intense reactions at times perhaps a little too studied. Nevertheless, the producers build a compelling case, and keep the production moving by flitting among two or three separate celeb investigators in each hour.

At its core the series represents a longform version of the advocacy-documentary brand HBO has championed so effectively, dispensing with present-both-sides evenhandedness that seems especially wasted on this topic, given the weight of the scientific evidence. (In terms of dissenting voices, Texas Gov. Rick Perry is among those shown denying any link between man-made greenhouse gases and the weather.)

In that respect, “Years of Living Dangerously” is banging its head against the climate debate’s version of an invisible ceiling — composed of greed, religion, partisanship and plain old apathy — that doesn’t let in ideas with the potential to pollute one’s existing point of view.

“A thermometer is not Republican,” Cheadle quips at one point, and it should be noted Weintraub, too, is a Republican, so party affiliation isn’t the sole determinant in this conversation.

“Years of Living Dangerously” has been assembled with all the glitz of a major Hollywood production. It’s just that unlike most movies associated with the time of year when temperatures are supposed to rise, nobody knows in this one what the ending will be.

TV Review: ‘Years of Living Dangerously’

(Documentary series; Showtime, Sun. April 13, 10 p.m.)

  • Production: Produced by Roaring Fork Films.
  • Crew: Executive producers, James Cameron, Jerry Weintraub, Arnold Schwarzenegger, Daniel Abbasi, Joel Bach, David Gelber; co-executive producers, Solly Granatstein, Maria Wilhelm; supervising producers, Jennifer Latham, Adam Bolt; producer, Jacob Kornbluth; music, Richard Marvin; theme, Thomas Newman. 60 MIN.
  • Cast: With: Harrison Ford, Don Cheadle, Arnold Schwarzenegger