It was George Monbiot who made the connection, but there’s a personal sting to the question. While I have the carbon footprint of a Darcy Bussell – don’t drive, rarely fly, grow my own (vegetables, too) and carefully offset bonfires and pipe-smoking – I don’t preach what I practise. Pressed, I blether about the Medieval Warm Period, the “Little Cooling”, grapes in Suffolk, ice-parties on the Thames and the extraordinary “fact” that the 1980 Mt St Helens eruption threw out more sulphurous compounds than all the factories on Earth since the start of the Industrial Revolution. But don’t mention Al Gore. He’s banned in this house, along with aerosols.

The question isn’t whether climate is changing, but what is to blame. A crippling tithe of international political effort and social action is directed to the assumption that we are. The notion that Gaia has the capacity to heal herself has been knocked on the head by the so-called “hockey stick”, a graph confected by Dr Michael Mann (and made famous by Gore) that seems to show our planet hotting up sharply, and 1998 as the hottest year since records began.

Except it doesn’t. For all its ubiquity, the “hockey stick” is bogus, a politically inspired gumbo of suspect data and dud methodology; Mann’s software was set up to mine for the desired result. Al Gore’s A Convenient Untruth, as I call it, is based on shoddy science; Snow White isn’t the only fantasy to win an Oscar. Christopher Booker, Britain’s most vocal sceptic, refers mildly in his book’s subtitle to a “costly ... blunder”; his text confirms what a 2007 Channel 4 documentary called a “swindle”.

Climate change is not a myth; it is the 21st-century myth, a canon of faith capable of overturning empirical science. Obama says the “facts are clear”, but are they? Mann’s bristlecone pines and other “proxies” are a poor index of climate warming. Polar bears aren’t drowning in the Arctic – this was the clubbed seal, if you like, of Gore’s appallingly manipulative film – but doing rather well. Greenland glaciers have retreated, but there has been a substantial increase in the main ice-cap. Tuvalu isn’t drowning; that was a scam. The biggest producer of CO2 is the ocean, and rising CO2 is a consequence of climate warming, not its cause. Gore tweaked the graph to make the peaks coincide.

Booker scores some rhetorical points – Gore’s Nashville home uses 221,000KW of electricity a year, 20 times the average, compounding the hypocrisy by buying carbon credits from a company he part-owns. Angela Merkel is hot for Kyoto while investing heavily in brown coal, the most polluting fuel of all. Behind David Cameron’s bike is a chauffeured Merc carrying a fresh shirt. But though Booker lands effective jabs, the book glances off the real issue.

The climate change debate – or enforced consensus – concerns the way science is done and perceived. As Booker says, “consensus” is not a term in science but in politics. The science isn’t beyond dispute. Far from it. Instead, a politically motivated orthodoxy has prevailed. Nature, a journal of record, suppressed a rebuttal of Mann’s methodology. Many of those charged with stewarding climate change, from the powerful IPCC downward, claim little relevant expertise.

It’s argued that there’s no point arguing while the world toasts. Scepticism is likened to appeasement or ignoring the threat of Hitler in 1934, which incidentally may have been the hottest year ever. Some even advocate environmental Nuremberg trials once the fires are put out. This is strong rhetoric but misses the point. Hitler’s was a declared threat; global warming has no agenda. Of course we should minimise use of fossil fuels, recycle and insulate. It’s common sense and doesn’t require an Armageddon scenario.

Climate change confirms CP Snow’s Two Cultures thesis. The media are dominated by arts graduates, and climate change is the kind of science attractive – no math required! – to arts people. Who understands “principal component analysis” (on which Mann’s graph depends) or the difference between capacity and actual output in the wind-farm debate? Snow went beyond scientific illiteracy to suggest that while scientists tend to be progressive, even utopian, a predominantly arts-trained culture cleaves to the pessimistic and apocalyptic. The twist is that climate-change politics, with American interests and muscle behind, has hijacked science to combat an apocalypse that may not even be happening.

We have to let scientists do science. The real global-warming disaster is a new “treason of the clerks”, a kind of Helsinki syndrome in which hostages fantasise common cause with their hijackers. The only answer is to free science of political control. At that point, the global warming “consensus” will evaporate and the world cool down again.