It strikes me that the documentary Manufactured Landscapes is a film in search of a subject. On paper, this is an exploration of the work and methods of the photographer Edward Burtynsky, whose work focuses on the impact that industry has on the natural world, presented in a non-editorial way. In execution, under the hands of Canadian director Jennifer Baichwal, this is instead a film about how awful it is what we're doing to the planet, and dammit we should stop that.

At this point, I think it's a really legitimate question whether the world actually needs another one of those, but we got one anyway. 'Tis pity. I will be honest: prior to seeing this film, I had no knowledge of this Burtynsky fellow. And now I really want to learn more about him, because he seems quite endlessly interesting. I mean, his work does. To be completely honest, we don't get any sense at all of what the man himself is like from Manufactured Landscapes, which tends to dilute its impact as a documentary about an artist.

There's probably nothing worse I can say about the film than this: it's absolutely at its most interesting when it is simply showing Burtynsky's photographs, PowerPoint style. They are exceptionally good photographs, you see. Unfortunately, when Baichwal follows up with her movie camera, the images lose their abstract apocalyptic quality and take a turn for the unimaginative and hamfisted.

The photographer at the putative center of this film is very upfront about his political aims: yes, he believes that it is the most vital thing that we stop raping the earth before it's too late, but you can't tell people, "you're wrong to believe X" and except them to hop on your side of things. Instead, he would rather present strong imagery without informing the audience what they're supposed to think or feel about it, just letting the raw power of the image fall on the viewers' eyes as it might.

This argument is made right in the movie, and yet Baichwal has concluded that the best way to celebrate her subject's work is to do exactly the opposite of all that: every lingering shot is clearly designed to slap us into agreeing with her. Now it just so happens that I do agree with her, but the fact remains that she's doing with her film something that is 100% removed from Burtynsky's aim, and that tends to cheapen the elements of the film that are meant to praise Burtynsky.

Broadly speaking, the film is concerned with two trips the photographer made to China: one in 2004 to visit the future site of the Three Gorges Reservoir as the inhabitants of that valley were forced to destroy their own cities; then, in late 2005, a trip dedicated to that country's factories and industrial waste. In the film, the two trips are reversed chronologically for little apparent reason, although it's clear that Baichwal uses the Three Gorges trip for more pointed political commentary.

Indeed, the first half of the film shows very little of the tendency that will ultimately scuttle the project. The opening shot of the film is extraordinary, one of the great moments of any movie this year: it's a simple tracking shot moving to the left past rows upon rows of factory workers putting together the individual components of what will ultimately turn out to be irons. At first it seems like nothing more than a well-executed cliché; as moments pass, it begins to feel a bit more compelling, as we realized just how damn big this factory is; and still moments later, as we've been locked in the shot for several minutes and time has ceased to mean much of anything, it becomes transcendent, and when the view switches to one of Burtynsky's photos taken from the end of the factory looking across the area of the tracking shot, it's a practically mystical moment. This is the one time that Manufactured Landscapes attains the dispassionate, documentary ideal of the photographer's work, and even more than that, it pushes into territory similar to Godfrey Reggio's Koyaanisqatsi, bringing a reflective abstraction to the inhuman grind of industry.

The 45-ish minutes that follow are a mostly traditional documentary trailing Burtynsky around the factory and in the surrounding cities, with occasional diversions into exploring his history and methods. It's not groundbreaking stuff, but more often than not it hits, if only because Burtynsky's work (which we see frequently) is undeniably engaging. Like last year's An Inconvenient Truth, it's not good cinema at all - I frequently found myself wondering why I couldn't get the same experience out of attending Burtynsky gallery show, not that such things are particularly common - but it does perform the most important basic task of the documentary, which is to make me aware of the existence of something that I had never heard of before.

So naturally that all gets pissed away, and the film turns into an unenlightening retread of a theme that has been covered in I-don't-know-how-many films at this point. Chinese authoritarianism is bad. Industrialism that damages the environment is bad. Rich people dicking over poor people is bad. None of these points ought be controversial, and I respected Baichwal's wish to make a film about them; but given that her chosen framework is a man who explicitly tries to show those themes in the subtlest way possible, her unambiguous tub-thumping approach to this material becomes all the more insulting to the audience's collective intelligence.