An Inconvenient Truth Starring: Al Gore. Directed by: David Guggenheim. Running Time: 96 minutes. Rated: Rated PG.Al Gore's introductory remark in his climate change documentary An Inconvenient Truth is catchy and quotable: 'I'm Al Gore, and I used to be the next president of the United States.' It brings a laugh, reminding audiences that but for a highly controversial re-count of votes in the 2000 United States presidential election, Al Gore could be running the country and arguably the world.For die-hards who still question the warnings of scientists that global warming is largely man-made, and a reality not scaremongering, Gore's film will be seen as political grandstanding and a possible tilt at the next US presidential election. But for those concerned about how little time may be left to change course and avoid the worst impact of global catastrophe, it is important to see this film, and apprise oneself of what Gore and many in the scientific community judge to be the facts. Interspersed with voice-overs and interviews, An Inconvenient Truth is structured as a multi-media presentation, and this reflects the film's genesis. Over the last few years, Gore has travelled the globe lecturing students, government officials, and anyone else willing to listen, about spiralling out-of-control carbon dioxide emissions pumped into the earth's fragile atmosphere through the burning of fossil fuels, and their impact on the world's climate. Gore's preoccupation with climate change began as a student at university in the 1960s, where he was influenced by Harvard professor Roger Revell. He was one of the first to measure carbon dioxide levels, and to link the increase in carbon dioxide emissions during the 60s and 70s with rising temperatures.The lecture begins with the iconic photograph of the Earth seen from the Apollo 17 spacecraft on its way to the moon in December 1972, and proceeds swiftly to a long horizontal graph spanning 650,000 years, which in the last 14 years reveals a spectacular 'hockey stick' rise of both carbon dioxide emissions and abnormally high temperatures. Most effective in highlighting the abnormality of this spike is Gore's use of a forklift on stage to lift him to where the spike ends, still on the rise.Debate rages hotly between political ideologues and scientists of many persuasions as to whether man-made pollution is responsible for this correlation, or if other unknown factors are to blame. What is not in dispute however - either in the film or through one's reading of newspapers and scientific journals - is the fact that the world's climate is changing alarmingly. Gore's argument is that we are facing a 'planetary emergency', and this is bolstered by a number of disturbing images that only the most hardened ideologue can fail to find worrying: scientists in the Antarctic examining the markings on ice cores which show the close relationship between carbon dioxide and temperature; an animation of a polar bear swimming in search of an ice floe as the polar sheets thin and melt; a map of how the face of the world will change due to the rise in sea level. Also shown are what would happen to Greenland and Western Europe if the Gulf Stream in the North Atlantic shuts down; how hurricanes like Katrina will increase in fury due to continued warming of the oceans; species loss of plants and fauna, and an accompanying rise in the incidence of malaria and other infectious diseases.Early in the film Gore makes the point that climate change, and the perils it poses for the long-term sustainability of life on earth as we know it, is not a political issue but a moral one. Dressed conservatively in a suit and tie, Gore's approach is low-key and interspersed with largely self-deprecatory jokes to both minimise and emphasise the direness of his message. But what he says is leavened with hope, if for no other reason than that a man of his decency and calibre is prepared to take on the naysayers, and prove them wrong. Jan Epstein is an associate of the Australian Catholic Film Office.