“Is it really possible to be bored by the end of the world?” the author Naomi Klein asks at the beginning of “This Changes Everything,” a climate-change documentary inspired by Ms. Klein’s 2014 book of the same name. Her question, as it turns out, is an unfortunate opener for a film that tries too hard to find comfort in crisis and hope in destruction.

Viewers, then, might be forgiven a wave of ennui as they watch familiar images of cracking earth and crumbling glaciers, as well as beleaguered citizens preparing to be trampled by the relentless march of the fossil-fuel giants. The tone is not improved by Ms. Klein’s super-sweet narration, which, in trying to avoid hectoring, too often coats complex issues in a deceptive simplicity.

But Ms. Klein can hardly be blamed for the difficulty of condensing her prodigious and wide-ranging research into 89 minutes. Nor can the director, Avi Lewis (who spent four years filming in nine countries), be chastised for highlighting the uplift that Ms. Klein finds as she pokes around the globe. It’s not easy to describe a systemic plundering of resources, and identify the culprit as global capitalism, without losing your train of thought or your cool, and the movie accomplishes this by focusing on the cheering reactions of the victims — in this case, a bottom-up environmentalism of regular folks fighting irregular circumstances.

And these so-called pollution mutinies are everywhere, organized by those who stand directly in the path of free-market exploitation. The young owners of a Montana goat ranch battle a ruptured Exxon pipeline; poor Indians use their bodies to obstruct the building of power plants on life-giving wetlands; an indigenous group in Canada rebels against toxic spills on ancestral lands. Their stories give the film its heart, and sometimes pierce our own; yet its embrace is so wide — including questioning the role of government and identifying pollution’s beneficiaries — that depth is a primary casualty.