Former U.S. vice president Al Gore has no plans to re-enter politics any time soon, but that doesn't mean he isn't engaged in the most important campaign of his life.

Gore has shifted direction since his defeat in the 2000 U.S. presidential election. He has taken his battle outside of the political arena and into the great outdoors in "a last-ditch, all-out effort to help save the planet from irrevocable change," according to the website for his new film, An Inconvenient Truth.

That "all-out effort" manifested itself in a travelling global warming road-show, and the new film documents Gore as he presents his argument in a bid to save the planet from what he describes as the greatest threat ever faced by mankind.

The release of the documentary, and a book by the same name, is part of Gore's mission to change the very way people think about the world around them -- before it's too late.

"I ran twice for president and twice for vice president. I'm proud of my service in politics, but I have found other ways to serve," Gore told CTV's Canada AM during a recent interview in Vancouver.

"I don't have plans to be a candidate again, and yet I am involved in a kind of campaign. But it's not for a candidacy, but a cause. And the cause is changing the minds of the American people and people in Canada and the rest of the world, because only then will politicians from every party face demands from the people to do the right thing."

Gore has been an environmental activist for years. In the early 1990s he penned Earth in the Balance, a bestseller that also took a hard look at climate change and the challenges facing the environment.

But his film debut only came after producer Laurie David, the wife of comedian Larry David, saw his lecture on global warming.

She was sufficiently inspired by the presentation that he has been tweaking for years, to approach him about turning the lecture into a film.

David linked Gore up with documentarian Davis Guggenheim, and the result was An Inconvenient Truth, which is playing now in select cinemas.

He was in Vancouver promoting the film and continuing his now decades-old campaign.

There's a subdued urgency to the way Gore discusses the environmental crisis he believes the world is facing. He's calm and in control, but there's an unmistakable energy just below the surface -- like a gathering storm.

The trailers for the film carry a similar energy.

Everything is controlled and strategic, but before-and-after images of melting glaciers and dried-up lakes stir up deep passions -- and fears -- about the fate of the planet.

And that's exactly what Gore hopes to accomplish with the film. Quite simply, he wants to change people's minds about the world and our role in it.

"By shifting public opinion massively, creating a sea change in the public mindset to match the unfortunate sea change we're causing with global warming -- then we'll see the political system break free from its paralysis and solve this crisis. That's the role I think I can most usefully play," Gore said.

Global warming, Gore says, has occurred at an almost glacial pace, but its movement has been steady and the phenomenon has picked up speed as the earth's population has grown and pollution has increased.

Gore says he was shocked to learn Canada recently abandoned the greenhouse gas reduction goals it had set under the Kyoto Protocol. The Conservative government claims those targets are far out of reach and can't be met.

Now is the time, Gore says, for nations like Canada to step up to the challenge and set an example for the rest of the world.

"If Canada does the right thing, it buttresses and lifts up other countries that might waver," Gore says.

"If Canada were to turn its back on its international obligations and wash its hands of this, the rest of the world could say 'well Canada is doing that, there's no way we can do the right thing.'"

Now, Gore said, the earth has reached the point where experts agree the global warming trend will be irreversible in 10 years, if drastic change doesn't take place now.

"The debate in the scientific community is over, there is no debate. The consensus is as strong as it gets."

That's a reality that is so big, so unmanageable, that people have trouble wrapping their heads around it, Gore conceded.

Part of the purpose of Truth, therefore, is to bring the massive concept of global warming and what it really means, down to a level that people can understand.

That's accomplished through audio-visual aides such as slides and film clips, as Gore takes the stage to deliver his road-show to packed audiences.

There's a vein of hope buried deep in the gloom and doom presented in the documentary.

"We can solve it, it's not too late, we have everything we need," Gore says.

"The political system, like the climate, can seem to move so slowly, but it can also pass a tipping point and move quickly."

"When we need to do something big and important we can shift gears and move quickly."

The buzz surrounding the film has people musing about a possible return to politics for the new, more media friendly Al Gore. He even appeared recently on Saturday Night Live as the U.S. president in an alternate universe.

Others are talking about a possible future in Hollywood.

But for the moment, Gore says he's focused on trying to save the world.

"I'm passionate about it, and when you believe in something you give it all you've got and sort of push everything aside.

"And I'm old enough to know a red carpet is just a rug."