Frack-up: "Gasland"

With America's oil supplies, and the market for documentaries about America's oil supplies, having apparently been exhausted, we move on. Natural gas has been positioned as the Great Transition Fuel that will wean us all off our addiction to the black stuff, and the good news is that there remain vast, untapped reserves of it across America and Europe. The bad news: the extraction process involves "fracking" (fracturing) the Earth and employing huge quantities of the local water supply, pumped full of a demonstrably carcinogenic chemical cocktail, to bring any gases to the surface. In short, there are bound to be consequences.

The filmmaker Josh Fox was one of those offered money by a drilling company for access to the gas under his Pennsylvanian homestead - money that was tempting indeed, until Fox began asking around, and heard things from his neighbours: reports of water coming out of the tap brown and fizzy, pets' hair falling out, children struck down with headaches. Something began to smell - well, not fishy, exactly, more... benzene-y. Gasland, the documentary inquiry that resulted, is somewhat schizoid and hesitant in its methods: Fox struggles to find an opening, before recasting himself - in suitably lugubrious voiceover - as "The Natural Gas Drilling Detective", whose peregrinations ("Everywhere I went, it was the same story") will eventually lead him all the way to Congress, and an altogether dismissive-seeming session on the subject. (Leave it Josh, we may urge; it's Gasland.)

The film's styling - in everything from Fox's specs to the onscreen fonts - is mannered-indie, yet Fox equally can't resist the odd Jackassy prank: whipping out his banjo to play a quick tune while gas-masked at one drilling site, encouraging his interviewees to set fire to whatever fluid is coursing through their pipes - both a showstopper, this, and demonstrable proof that something isn't right. This isn't, however, the work of a big-city filmmaker who's landed in the sticks with his mind already made up; Fox never condescends to his subjects, in the manner a Michael Moore would. In fact, we learn the filmmaker is the son of counterculture folk who built their home themselves, as a retreat in an unspoilt corner of the Catskills, and something in his voice, and about the final sequence of images, reminded me of Jedediah Purdy, the nature boy whose late 1990s tract For Common Things mixed Henry David Thoreau with Naomi Klein, and cast globalisation as, above anything else, an enemy of our shared natural resources (fresh air, clean water, fertile soil).

Gasland offers flashes of familiar liberal-left boogeymen - Dick Cheney (who formed the energy task force that authorised the selling-off of communal land), Halliburton (one of those companies responsible for the drilling) - yet as the EPA whistleblower Weston Wilson reframes it, "We're still asleep at the wheel. And don't assume just because Obama's been elected things have changed in that regard." Early on in Gasland, I did question its relevance to UK cinemagoers - beyond the immediate one of being a good yarn - but, by the end, the cumulative weight of the film's argument, of the evidence it spots flowing downstream, won me round. Anyone who strikes this kind of blow against our planet, wherever whenever, is surely slapping us all about the face.

Gasland opens in selected cinemas from today.