Socially-conscious filmmakers are no rarity in the motion picture business. You could probably make a list of thousands of names that stretches through the entire history of the medium to document every director or writer who have used their movies to comment on where we are as a species and a civilization. The important question is how that consciousness is deployed in the work: does it feel like an organic part of the story, or is the social message used as a bludgeon? Does the filmmaker trust the audience to pick up on the subtext without lecturing them?

Unsurprisingly, there’s a wide spectrum here, from the subtle touch of Vittorio De Sica’s Umberto D. and William Wyler’s The Best Years of Our Lives to the heavy hand of Neill Blomkamp’s Elysium. Or consider the evolution of a single director’s output, like the career of Alexander Payne. Starting with his breakout Election in 1999, Payne has established himself as filmmaker who opens up complex issues, but often finds a wryly comic way to approach it. He explored the anxieties of retirement in About Schmidt and mid-life crises in Sideways. Then he dove into questions about medically-assisted death in The Descendants and about the ravages of dementia in Nebraska. Every time, Payne found a warm, personalized way to approach his subject.

By contrast, in his new film Downsizing, Payne expands his perspective to the entire planet, and in so doing loses some of the authenticity that he’s been known for. Downsizing doesn’t seem to trust us to pick up on its save-the-world thesis, and ends up feeling more like an over-eager university student giving a speech than a satisfying moviegoing experience. It’s not a bore, but it wastes too much energy wagging its finger while the story is lagging behind.

The premise of Downsizing is a classic move from sci-fi, but relatively new for an Alexander Payne film. It takes a world-threatening problem (overpopulation and climate change) and imagines a bonkers solution: what if a Norwegian scientist discovered a way to permanently shrink people down to five inches in height, and build tiny utopian communities that will put far less strain on the environment? To entice people to undergo the procedure, candidates are shown that every dollar goes a thousand times further in downsized cities. This allows middle-class people the chance to own 12-bedroom mansions and buy fabulous luxuries that were previously out of reach (a set of diamond jewelry goes for $83).

It sounds potentially unforgivably silly – the jokes do occasionally approach a Disneyfied Honey, I Shrunk the Kids level – but for the most part Payne keeps a handle on the proceedings. He centres the story around an everyman named Paul Safranek (Matt Damon) who’s living in a run-down home with his wife Audrey (Kristen Wiig), dreaming of a better life. When an acquaintance from high school (Jason Sudeikis) decides to downsize, the Safraneks begin to consider the process as well, tempted by the gleaming metropolis for “the small” called Leisureland. However, once Paul decides to flip the switch, he finds that humanity’s troubles have a way of following us around, no matter how extreme of a solution we chase after.

As always, Payne marshals a large and varied cast – Christoph Waltz is on hand as a Serbian import/export guy operating outside the law in Leisureland, and Neil Patrick Harris and Laura Dern appear as promoters for the downsized lifestyle. The best discovery in the film, however, is Hong Chau as Vietnamese dissident Ngoc Lan Tran, who was downsized against her will by the regime in her home country, and immigrated illegally to America in a TV box. Initially, Chau riffs on the “angry Asian” stereotype, but thankfully, her character expands into something far deeper, someone who’s almost the emotional core of the film. It may take a while to get there, but it’s encouraging to see such a prominent and meaningful role for an Asian actor in a film set for a big Christmas release.

But therein lies one of the biggest drags about Downsizing: it’s easily 30 minutes too long. The jokes about the tiny scale that Damon’s character now lives on just can’t sustain a 135-minute treatise on the shallowness of human beings. Payne and his frequent writing partner Jim Taylor include plenty of sharp dialogue, but certain scenes, like a party scene near the halfway point and a lengthy epilogue, suggest that Payne’s not confident he’s getting through to us. It’s as though the film is saying, “Here’s that doomed humanity thing again. It’s really bad, right? Like we’re just all terrible creatures, right?!”

The ideological pitfall of Downsizing may be that the existential threat, like so many other reasonable films about climate change (i.e., not the upcoming Geostorm) is too abstract. It’s harder to rebuke the materialistic desires of the people who downsize, because the film never really shows the damage to the environment that the process is supposed to combat. The film sort of calls out for Paul Safranek to uncover some conspiracy unique to the shrunken communities, some indication that the participants are being deceived. Instead, we get a lot of hollow philosophizing, and in a film trying to make itself heard, that’s no small thing.

Downsizing gets two and half stars out of four.

Stray thoughts

• I desperately wanted more dark humour, like seeing a downsized person get snatched by a bird or an insect.
• The fate of the Norwegian colony at the end owes a huge debt to the Fallout games.
• The climate catastrophe described at the end of the film doesn’t make a lot of sense, especially given the engineering capabilities displayed in the design of Leisureland.