GORE TURNS UP HEAT ON ENVIRONMENTAL ISSUE.

Byline: Bob Strauss Film Critic

`An Inconvenient Truth,'' which opens today, is, essentially, a rousing, upbeat concert film about the end of the world.

Starring Al Gore.

Yes, that Al Gore. The candidate who was so stiff that even though he probably won the 2000 election, they gave the presidency to George W. Bush anyway.

I don't know how Gore morphed from that into an environmental rock star -- a really good acting coach, I'm guessing -- but the change is downright marvelous.

And there's much to be said for fronting a cause that you've always been passionate for, as Gore has about global warming since his college days.

Fronting a slick slide show that he's presented some 1,000 times in venues ranging from school auditoriums and hotel conference rooms to more traditional, concert-size halls around the world, Gore comes off as accessible and witty. Sometimes, he's as evangelical (and mesmerizing) as a Baptist preacher from his home county in Tennessee. And he's unfailingly a capable teacher of alarming scientific facts that, at least the way they're shown here, are vital stuff that everyone needs to know about.

Gore presents pretty convincing photographic, statistical and historical evidence -- interspersed with some eye-catching animation -- that global warming is accelerating at a civilization-threatening speed, right now. And of course, we have to do something about it, before the polar ice is all gone, shifting weather patterns destroy whatever land the rising oceans don't claim, and new diseases wipe out us and the few remaining species who survive the other climate calamities.

Produced by, among others, liberal luminaries Laurie David and Lawrence Bender and directed by Davis Guggenheim (TV's ``Deadwood''), ``Inconvenient'' mixes its ecological message with quick bio segments.

Though these personal interludes are short and sweet, they're as cannily designed as one of those candidate hagiographies political conventions show. Gore sensitively talks about the near-death of his young son and with real impact when addressing his late sister's lung cancer, a tragedy that led his father to finally stop growing tobacco on the family farm.

Gore's claim that, as a child, he did not distinguish working that land from playing sounds suspiciously like that story about George Washington and the cherry tree, though. And shots of him hauling his own luggage, alone and unrecognized, through airports don't so much reinforce an unpretentious everyman image as make you wonder who told the passers-by not to look at the guy that camera crew's filming.

That aside, you'd have to be willfully stupid, or partisan, not to be moved, enlightened, deeply concerned and, yes, entertained by Gore's presentation of his message.

Where was this talent and sincerity in 2000? Maybe if he'd been this charismatic on the hustings, the Supreme Court would've let Gore actually be president.

Well, history's loss may be the environmental movement's gain. And if you believe the dire warnings Gore's ``Inconvenient Truth'' show persuasively argues, something much more important than the U.S. and its citizens' interests may benefit from the ex-veep's efforts.

Bob Strauss, [phone]

bob.strauss(at)dailynews.com

AN INCONVENIENT TRUTH - Three stars

(PG: mild thematic elements)

Director: Davis Guggenheim.

Running time: 1 hr. 40 min.

Playing: Opens today at ArcLight, Hollywood; and Laemmle Monica, Santa Monica.

In a nutshell: Al Gore's slide show about global warming makes for an informative and entertaining documentary about how we're all probably doomed. Counterintuitive, I know, but maybe it works so well because Gore, improbably, proves to be a genial and inspiring presenter.