An Inconvenient Truth
But Alex Higgins (TES, September 28) complains that it is "intellectually dishonest" of Derek Tipp to suggest water vapour absorbs more heat than carbon dioxide. For the record, water vapour is the most significant greenhouse gas; CFCs are the most powerful gas, molecule for molecule; human activity leads to emission of more carbon dioxide than any other greenhouse gas. Higgins seems to support my research that serious misconceptions do not stop people holding strident views about global warming.
I have no axe to grind either way, but the evidence that supports the enhanced greenhouse effect is not conclusive, so why stifle scientific discussion? Surely such a debate would provide an excellent opportunity for pupils to see how scientists come to different interpretations of the same data. The scientific "consensus" argument is irritating but instructive. Consensus implies doubt. When it comes to physical laws, no one talks about consensus; there is simply the implied caveat that a law is contingently true, to be modified or discarded if it fails to fit new data. Besides, history is littered with examples of scientists responsible for paradigm shifts who first had to endure ridicule from colleagues. Wegener and plate tectonics is the example favoured by Al Gore. But no doubt Higgins would have dismissed Wegener as a "fringe" scientist.
By spinning what little science there is in his film, Al Gore risks damaging the credibility of science; thankfully, no scientist is screened endorsing what he says. Surely our pupils deserve to be taught by subject specialists, not politicians via DVD. Screening The Great Global Warming Swindle, the documentary broadcast this year by Channel 4, in schools could go some way to restoring some balance. At least the story is told by real and eminent scientists. They simply offer an alternative explanation for global warming with a better fit to the temperature record.
Dr Mike Follows, Willenhall, West Midlands.