It must drive you mad being a climatologist. You spend your life measuring carbon emissions, and monitoring glaciers and studying lumps of moss from Siberia, and then you hear someone on a radio phone-in yelling, "How can they say the world's getting hotter? I mean at night, it's colder than what it was in the day, so it's got colder, not hotter. They must think we're mugs."

Then a series of articles will appear in which it's claimed: "A new study by Professor Zbygnewsk of Cracow proves sea levels have gone back down so everything's fine", before it turns out he's a Professor of Latin dancing, and has a history of solvent abuse.

Or there'll be letters in the Daily Telegraph that go "Dear Sir: May I recall the carefree days when one would enjoy the sport of sailing to Greenland to melt icebergs with a blowtorch. Alas, these days I fear this too would be frowned upon by the climate change fascists. One dreads to think what these paragons of political correctness will try to ban next."

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Or, rather than waste time fooling about with analysis, the scientists could read the front page of yesterday's Daily Express, that declared "100 reasons why global warming is natural. No proof that human activity is to blame." And there inside were the reasons, as outlined by Jim McConalogue of the "European Foundation". Number one was, "There is no scientific proof." So the retort to all the studies from the International Panel on Climate Change, Nasa, the Royal Society, all 928 papers on the matter in the journal Science and every major scientific institution, is: "Yeah but there's no proof."

You'd expect number two to be: "Because it's all, like, made up and stuff." Then number three would be, "Dur, whatever", and number four, "I've already TOLD you in number ONE." Instead there's number 30: "Global warming is the argument of flat-earthers." How is that relevant, I wonder. Maybe number 42 was: "My brother-in-law says it's getting warmer and you don't want to trust him."

I gave up at around 40 so maybe the rest was genius, but more likely it went on: "58. It's claimed global warming is making some species die out, but there's still loads of rabbits."

The issue that's boosted the disbelievers is the discovery of messages, sent to scientists, encouraging them to tweak their statistics in favour of proving climate change. Which was unhelpful and crazy, but doesn't disprove the sackfuls of evidence that climate change is carbon-related, any more than it would disprove the existence of gravity if it was discovered Isaac Newton had shouted: "We want to prove this theory beyond all doubt so chuck the apple as hard as you can."

But also, the people who insist this incident proves all the evidence is unreliable, are similar to creationists who pick up on flaws in the detail of Darwin's theories, without necessarily applying equal rigour to their theory, that light was created before the Sun, and Eve didn't notice she was naked until she was persuaded to eat an apple by a talking snake. Because many prominent climate change sceptics seem by coincidence to be in the pay of the energy industry.

So the Heartlands Institute received $676,000 from Exxon Oil, to discredit the idea of climate change. Patrick Michaels, often presented as an expert who disputes the link between carbon emissions and climate change, has received over $100,000 from energy companies to put their case.

So when they inform us they've discovered there's no proof of climate change, and the planet's just going through its natural cycle, it's as meaningless as if a spokesman for Fairy Liquid was introduced by Patrick Moore on The Sky at Night, and said: "The orbit of Neptune seems to confirm that a bottle of Fairy Liquid washes up to 40 per cent more dishes than any other brand."

They're not all paid by Exxon. The genius with his 100 top global-warming denying tips seems to be doing it for free. But he is a member of Conservative Right, and that's the clue for the other motive of these people. For them, climate change threatens the free market. How can oil companies make their maximum profits if they have to worry about making the planet fizz into oblivion? It can't be true because it mustn't be true.

So no matter how much evidence there is they'll carry on disputing it. Sussex will be desert and Guernsey will disappear, and they'll tell us: "If sea levels are rising the obvious answer is to build roads over them. After all, it's not the roads that are rising is it?"