If you don't understand the climate change issue or are dubious about whether the human-caused emissions of greenhouse gases are causing the planet to catastrophically heat up, then you need to see this movie.

However, questions on how to make change happen -- and who is standing in the way -- are given short shrift, in my opinion.

So how you feel about the film might well depend on your feelings about the climate change issue -- and its central storyteller, Al Gore.

The movie is the documentary film version of a multimedia slide show the former vice-president and 2000 presidential candidate has been giving for years.

"Hi. I'm Al Gore: I used to be the next president of the United States," he dryly opened one lecture, generating applause, hoots and laughter. "I don't find that particularly funny," he deadpanned.

Gore, of course, is referring to the disputed results of the Florida ballot. He won the nation-wide popular vote, but under the vagaries of the U.S. electoral college, the vote came down to the 25 electoral college votes of Florida. The vote was extremely close and controversial. I'll leave it at that.

His political career at an end, Gore decided to make fighting climate change his passion.

However, he makes it clear he had an interest in the subject going back to his college days, when one of his professors started to measure CO2 levels in the atmosphere.

Gore has become progressively more convinced that we are entering a crisis phase; that we have a 10-year window of opportunity to put the brakes on greenhouse gas emissions. After that, it will be too late, he says.

The evidence he presents is, to my mind, difficult to refute.

Carbon dioxide and atmospheric temperature are very much linked, but as Gore says, never before in history has there been more than 300 parts per million of carbon dioxide in the atmosphere.

On March 20, the Mauna Lona observatory in Hawaii recorded a level of 379 parts per million, according to an AP story on CBSNews.com.

By the middle of this century, Gore said projections show that CO2 levels will be pushing 600 parts per million. The story above said by 2100, the range could be from 650 to 970 parts per million.

In some sense, that's academic.

Where Gore helps bring it home is by showing the changes to our planet right now from global warming, using graphs, charts, video, photos and even Simpsons-esque cartoons.

The crumbling of glaciers in Greenland and the Antarctic, the disappearance of the snows of Mount Kilimanjaro, the drying up of Lake Chad in Africa ... the evidence is clear that something is indeed happening here, to paraphrase the old Buffalo Springfield song.

Gore explains why this happening and makes the argument that in a metastudy of peer-reviewed scientific journal arguments, there were none that disputed the basic theory of global warming.

In the press, however, about 57 per cent of articles dispute the global warming theory (I'd love to see some numbers specific to Canada).

While he touches on some of the Bush administration's shenanigans on climate change, I wish for Americans' sake that Gore would have gone a bit deeper into the politics of climate change in the U.S. and Australia for that matter -- the two industrialized countries that failed to ratify the Kyoto Accord.

(During a movie promotion stop in Vancouver, Gore ripped Prime Minister Stephen Harper for the Conservative government's position on climate change).

And bizarrely, the film delays talk of what people can do to help until the end and intersperses it with the credits!

I've also got a bone to pick with the movie's website, climatecrisis.net.

Is this website supposed to help people fight climate change or is it designed to primarily to help market the movie? (I know: stupid question).

While it has a nifty carbon impact calculator, virtually none of the facts from the movie make it onto the website. I guess they're trying to save stuff like that to help sell either DVDs or the companion book.

That's unfortunate, because the climate change issue should transcend commerce, especially given Gore's position on how the climate change fight is the moral imperative of our time.

At the end of the day, however, a potential moviegoer wants to know whether the movie will be worth devoting X amount of time from their life.

I'd unequivocally say yes: An Inconvenient Truth is both informative and watchable. While it has minor flaws, it could change the way you'll look at the world.