“2014 was the hottest year on record.”

Q: If the above statement is not true – and (see below) it isn’t – would it make it any more true were it to be uttered in an important speech at Davos by fashion designer, songwriter and hip hop producer Pharrell Williams?

A: Nope.

Q: OK. Then how about if Pharrell, while chilling in the outdoor hot tub with George Soros, Bono and Paul Krugman at their seven-star hotel in Davos, were to write a chart-topping song about it – something along the lines of Happy, only catchier, more uplifting – and it became, like this massive club hit across the world and all the kids everywhere were singing “2014 was the hottest on record.” Would that make it more true?

A. Nope.

Q: Sigh. How about if “2014 was the hottest year on record” was remixed as a Live-Aid-style all-star extravaganza starring One Direction, Lady Gaga, Bruno Mars, Coldplay and others with a hilarious viral sensation video co-directed by Richard Curtis and James Cameron, featuring James Corden, Ricky Gervais, Matt Damon, Gillian Anderson and Marcus Brigstocke with a special cameo from Al Gore sending himself up as the Comedy Beached Whale who had lost his way because his sonar had been tragically disrupted by offshore wind turbines. Would that work?

A. Nope.

Q. OK – all the above, plus a speech by all the G20 leaders endorsing the statement that “2014 was the hottest year on record”, plus a statement from the heads of all the world’s leading scientific academies, plus a detailed analysis by Roger Harrabin on BBC Radio 4 and a supportive article in The Spectator by legendary journalist Nick Cohen declaring that anyone who doesn’t believe that “2014 was the hottest year on record” is a complete moron?

A. Still nope.

You may think that what I’m stating here is incredibly obvious. If an empirically verifiable statement – eg “2014 was the hottest year on record” – is untrue, no amount of repetition, from no matter how many celebrities, politicians and scientists can make it otherwise.

Why then, do all these people go on repeating the lie anyway?

Before I explain why, let me briefly rehearse the background to the “2014 was the hottest year on record” meme.

It began spreading earlier this month when NASA GISS’s director Gavin Schmidt held a press conference to declare that 2014 was the hottest year ever recorded. This sounded jolly impressive and naturally generated excited “2014 was the hottest year on record” headlines around the world, everywhere from the BBC and the New York Times to the Guardian, Nature, Slate and Vice. No half way informed person, we can fairly safely say, will have got through January without having seen at least once – and probably several times – a headline to the effect that “2014 was the hottest year on record”.

But there were, it subsequently emerged, several things wrong with this headline story.

The first – which, admittedly, you would have realised had you read reports like this one in the Guardian – is that “hottest year on record” isn’t quite so dramatic as initially sounds. That’s because the temperature records it is being compared with only go back to 1880. (Oddly enough though, no newspaper ran the headline “2014 hottest year since 1880” or “2014 hottest in 134 years”)

The second is, as David Rose noted in the Mail On Sunday, that the criteria by which NASA declared “2014 was the hottest year on record” do not stand up to serious scientific scrutiny.

Yet the Nasa press release failed to mention this, as well as the fact that the alleged ‘record’ amounted to an increase over 2010, the previous ‘warmest year’, of just two-hundredths of a degree – or 0.02C. The margin of error is said by scientists to be approximately 0.1C – several times as much. As a result, GISS’s director Gavin Schmidt has now admitted Nasa thinks the likelihood that 2014 was the warmest year since 1880 is just 38 per cent.

Odds of 38 per cent are not a racing certainty. If you translated it into a bet you’d lose more often than you’d win. NASA was lying to us. Or, at best, wilfully misleading us.

And the third problem, as Christopher Booker noted, is that the satellite temperature records tell a very different story from the surface temperature records quoted by NASA. This would suggest – as sceptics have been arguing for some time – that the land surface temperature data sets are untrustworthy. There are too few weather stations; too many of them are subject to the Urban Heat Island effect; and, in any case, the raw data has too often been adjusted by alarmists for reasons that appear to owe more to politics than science, since the adjustments always seem designed to make the early years of the 20th century cooler than they were in order to make the subsequent increases in temperature more dramatic.

Now you’ve got the background, let me return to my question.

If the statement “2014 was the hottest year on record” is untrue – and demonstrably untrue – then why are so many people who ought to know better continuing to claim otherwise?

The answer, as often where outbreaks of mass hysteria are concerned, can be found in Gustave Le Bon’s 1895 masterpiece translated in English under the title The Crowd: A Study Of The Popular Mind.

This brilliant study of how to influence the mob by engendering groupthink was admired by, among others, Freud, Hitler and Mussolini.

Here is Le Bon on the most important weapon in the demagogue’s armoury:

It was Napoleon, I believe, who said that there is only one figure in rhetoric of serious importance, repetition. The thing affirmed comes by repetition to fix itself in the mind in such a way that it is accepted as a demonstrated truth. The influence of repetition on crowds is comprehensible when the power is seen which it exercises on most enlightened minds. This power is due to the fact that the repeated statement is embedded in the long run in those profound regions of our unconscious selves in which the motives of our actions are forged. At the end of a certain time we have forgotten who is the author of the repeated assertion, and we finish by believing it. To this circumstance is due the astonishing power of advertisements. When we have read a hundred, a thousand, times that X’s chocolate is the best, we imagine we have heard it said in many quarters, and we end by acquiring the certitude that such is the fact.

Now you understand why NASA GISS’s Gavin Schmidt held that press conference and why he said what he did. Like so many of those “experts” abusing the prestige of their distinguished institutions in order to push the great global warming scam way past its sell-by date, he has long since parted company with empiricism, rigour or ethical restraint. He and his ilk have largely abandoned science, in favour of propaganda. No offence intended to chocolate advertisers – but that, in essence, is what these charlatans have become.