REVIEWED - AN INCONVENIENT TRUTHTHIS cinematic record of Al Gore's PowerPoint presentation on the dangers of climate change has become one of those pictures - Fahrenheit 9/11 is another - the appreciation (or condemnation) of which is believed to reveal certain telling things about the viewer's political leanings. Dare to express reservations and you unveil yourself as a strip-mining, monocle-wearing robber baron.

With that in mind, let us address Gore's arguments first. Throughout the film's 100 minutes, the former vice-president clearly and concisely makes the case that increased carbon emissions have caused dramatic changes in the earth's climate, which could, if not addressed rapidly, have further catastrophic consequences.

Depressingly, the science does, on examination, appear to be sound. In this respect, An Inconvenient Truth (well titled) stands as a vital piece of work. We ignore this awful message at our peril.

But has Davis Guggenheim, formerly a director of high-quality television such as 24 and Deadwood, managed to make the lecture into a film? What, aside from duty, would persuade viewers to forego the various car chases and explosions available in the multiplex to watch a middle-aged man spend an hour and a half telling them they (and their descendants) are all going to drown?

Well, surprisingly enough, the various visual flourishes Gore devised for his speaking tour translate quite well to the larger screen. The ghastly vista of shrinking glaciers and terrible new deserts seem that bit more insistent when blown up to the size of a double-decker bus. More astonishingly still, Al Gore, once a personified synonym for woodenness, has developed into an engagingly witty and self-deprecating speaker. The fact alone that he includes a faintly scurrilous caricature of himself from Futurama demonstrates he's loosened up somewhat.

Indeed, if the presentation does have a flaw it is to do with its eventual conformation to a Hollywood template. For most of the lecture Gore, recalling a Tennessean version of Private Fraser from Dad's Army, experiments with different ways of telling us we are doomed. Then, as the third act looms, he reveals that we are, in fact, going to be okay after all. Governments and citizens will, this characteristically optimistic American believes, change their ways. Carbon emissions will decline. Manhattan, New York and Dublin will remain above water.

A happy ending. I wish I could believe it.