A movie whose marquee says it “stars” Al Gore is bound to draw some scoffers from the opening credits.

But like him or not, Gore’s performance in the documentary “An Inconvenient Truth” is informative and entertaining. As long as you can get past the cynical idea that the film is Gore’s way of combating his robotic stereotypes through dramatic political theater, the film even manages moments of poignancy.

While most of the film is about global warming and the science to support it – those with chart and graph phobias should stay away – it’s also simply about Gore.

He ties his son’s near-death hit by a car to his awakening about the environment, and his sister’s death by lung cancer to his family’s decision to not grow tobacco.

And ultimately, Gore weds the truth about smoking to the skeptics on the environment. He points to 1950s cigarette ads that claim most doctors smoke, to show the dangers of when we allow pop culture to dictate our beliefs over science.

The film is, for the most part, a rendering of the slide show Gore has spent the past six years peddling across the world. It’s both surprisingly entertaining and disturbing at times, with computer animation simulating things like an underwater Florida, thanks to the melting of Arctic and Antarctic ice and a polar bear stranded in the ocean with no ice on which to rest.

The film makes it clear global warming is yet another issue in which skeptics have suggested a worldwide conspiracy rather than accept peer-reviewed science, and Gore hammers this home. He lives up to his reputation as a debater, deconstructing many of the worn arguments against global warming with science, sources and proof.

Still, ideologues will remain unconvinced, and that’s why “An Inconvenient Truth” might prove less effective at bringing skeptics around than it will be at calling to action those who accept the science on global warming and want to see policy changes reflecting that science. The end credits feature a series of encouragements to change behaviors, political leaders and policies while Melissa Etheridge belts out a song written for the movie.

But again, this movie is also about Gore: his campaigns since the 1970s in Congress to pass environmental laws, his role in the Clinton administration in the 1990s and his near-successful run for president in 2000.

“An Inconvenient Truth,” whatever the legitimate social consciousness it strives to raise, might also prove to be a very convenient campaign tool should Gore decide to run for president again in 2008.

So is the film just a 100-minute campaign ad?

Maybe.

But it’s a damn good one.