Steve Connor: The unbridgeable gap between law and science

It is always amusing to see how the legal mind treats science given that both aspects of human activity are about the search for the truth. The trouble is, the law, like politics, is about certainties, whereas science is as much about what we don't know as what we know for sure.

Nowhere is this more clearly seen than in the case this week in which a High Court judge ruled that the Oscar-winning film about climate change by the former United States vice-president Al Gore is littered with scientific inaccuracies. Mr Justice Burton has ruled that the film – An Inconvenient Truth – is not simply a science film, but a political film, and as such it should only have been distributed to schools with a clear health warning about its politically-inspired nature.

An Inconvenient Truth came to be the subject of a High Court case because of a father of two boys, who was also a governor at his local school, objected to the Government sending a copy of the film to every state school. The father, Stuart Dimmock, argued that showing the film in schools would amount to government-sponsored political indoctrination.

Anyone who has seen the film will be aware that it is not an ordinary, objective science documentary. Mr Gore is, after all, a consummate politician and the film promotes him as much as the cause to which he has long been associated – he is not some late convert to the dangers of global warming, as some people have suggested.

I have first of all got to declare an interest here. Last March I spent a day with Al Gore (along with scores of other people) going through the slide show on which the film is based. The aim of the "training session" was to teach people to show the slide show to their own communities.

In the event, the only people I've shown the slides to were a group of Russian scientists and journalists at a course funded through the British Embassy in Moscow about climate change in mountain regions. I have to admit there were points when I too became uneasy with some of the rather simplistic assumptions behind the slides.

Take, for example, the famous graph in the film showing the rise and fall of carbon dioxide and temperatures over the past 600,000 years. Gore's line in the film is that they must be related. They are indeed related but not in the simplistic cause-and-effect manner that he suggests, with increases in carbon dioxide driving subsequent rises in temperatures.

In this long, ice-core record of the Earth's climate it is temperature that rises before carbon dioxide levels, and not the other way round. But this does not negate the central fact that the two are in lockstep. In the past, temperatures rises have triggered an increase in carbon dioxide levels, which have led to a feedback, causing greater temperature rises.

Gore's "error" was to skate over the complexity of the issue for the sake of making a point, which he demonstrates starkly by mounting a cherry picker to show how high carbon dioxide levels have risen today. The point about carbon dioxide levels now is that they have become a central driver for increases in global average temperatures – man-made climate change.

Another problem with Gore's film is his example of how the "ocean conveyor" which pumps heat to western Europe can be rapidly shut down. He cites how this has happened in the past by the sudden release of melt water from North American glaciers after the last ice age.

Mr Justice Burton says in his judgement that the scientific consensus is that this shut-down is unlikely to occur. What he does not mention is that a recent study has found that Gore's scenario could not have occurred – the timing is all wrong. This is the problem with science – conclusions and suppositions can so often be superseded by new findings.

The judge also criticised Mr Gore for suggesting that Hurricane Katrina was the result of global warming. True, it is difficult to ascribe any single climatic event to climate change, but again what the Mr Justice Burton failed to mention is that a new, peer-reviewed study published earlier this year found that the increase in both hurricane intensity and frequency over recent years can be linked with warmer sea-surface temperatures.

The point is, science is continually finding things out and in doing so creates new areas of uncertainty as well as resolving past problems. This is what schoolchildren should be taught. But one wonders whether this is possible with a Government intent on increasing the number of "faith" schools. Children should be taught to question everything, especially films made and distributed by politicians, rather than relying on faith alone.

s.connor@independent.co.uk