Director Avi Lewis, right, and author Naomi Klein of the film 'This Changes Everything,' stand for a photo on the red carpet during the Toronto International Film Festival press conference announcing the 2015 Canadian features and shorts lineup in Toronto on Wednesday, August 5, 2015. THE CANADIAN PRESS/Aaron Vincent Elkaim

TORONTO - In tackling an issue as big as climate change, journalists-turned-activists Naomi Klein and Avi Lewis knew they needed more than Klein's 2014 book "This Changes Everything: Capitalism vs. The Climate" to inspire action.

There would have to be a website and a companion documentary, "This Changes Everything," directed by Lewis.

And the film's theatrical rollout should include special community screenings, complete with audience discussion.

What about a headline-grabbing manifesto, signed by celebrity supporters including Rachel McAdams, Ellen Page and Leonard Cohen?

And all this, of course, should unfold in tandem with the campaigning of Canada's political leaders in advance of the Oct. 19 election.

Thus, an expansive multiplatform campaign was born.

With all these elements now in play — the doc hits select theatres Friday — Lewis noted their environmental call-to-arms has turned into an all-consuming endeavour.

"We have a conviction that if you want to introduce new framings, new narratives, new ideas, we need multiple points of entry," Lewis explained recently by phone from New York.

"We conceived of it ... more than five years ago."

That was when the husband-and-wife team began researching individually in their respective mediums, sharing their discoveries along the way.

"For a number of years I was making a film about a book that hadn't been written yet," notes Lewis, who enlisted Klein as the film's narrator.

"The film is my interpretation of Naomi's core thesis, and her narration is her selecting one big idea from a book ... to inform these particular stories that I decided to shoot."

They covered the globe in making the film, visiting nine countries and five continents to profile seven communities forced into action by burgeoning environmental threats.

They include the controversial Alberta oilsands; northern Greece mining projects that threatened mountains, seas, and tourism; and a proposed coal-fired power plant in Andhra Pradesh, India where villagers feared for the safety of crucial wetland.

All over the world, Lewis says this issue "is the big one."

"The climate crisis is the issue that connects the dots among all the other issues, especially when you look at ... the economic system that put it there," he says.

"This is the fight of our lives."

Joining the fight are several celebrity backers: "This Changes Everything" is executive produced by "Gravity" director Alfonso Cuaron, actor Danny Glover, and "Family Guy" creator Seth MacFarlane, with co-executive producers including actress Pamela Anderson, fashion designer Vivienne Westwood and fellow filmmaker and philanthropist Susan Rockefeller.

Even more are signatories to the "leap manifesto" released last month, which called on the next federal government to transition Canada entirely off fossil fuels in as little as 35 years.

Lewis says the major political parties are out of touch with Canadians.

"Scratch the surface and people know that there's something fundamentally wrong with the underpinning logic of our whole system," he says. "There is an enormous audience, an indescribably broad audience that is just yearning for that message."

Meanwhile, he says their multipronged approach to reach audiences is a growing phenomenon, noting that "funders are increasingly pushing filmmakers to look at impact and to bake that into the whole process."

"It can feel tacked on, those engagement campaigns, so it's great to consider that from the beginning," he says.

"This Changes Everything" hits select theatres Friday, followed by an iTunes release Nov. 3.

News from © The Canadian Press, 2015