Did you know that 2014 was the hottest year ever recorded in the entire history of the world? Probably you did because it’s been all over the papers. Not only that but President Obama slipped it into his State of the Union address and the president of the World Bank quoted it at Davos and the singer and rap producer Pharrell Williams is so concerned that he plans to stage a series of Live Earth concerts with Al Gore to emphasise the seriousness of the problem.

And these luminaries must know what they’re talking about, right? After all, it’s not just one distinguished scientific institution which has endorsed the ‘2014: hottest year on record’ claim, but a whole clutch of them.

First out of the gates was the Japanese meteorological office, then our own Met Office, then most recently Nasa’s Goddard Institute of Space Studies. These, in turn, were doing no more than agree with the US National Oceanic and Atmospheric Administration and the University of East Anglia’s Climatic Research Unit. So many international experts, all in agreement: what kind of ‘scientifically illiterate’ denialist nutcase would you have to be to dispute a consensus as overwhelming as that?

A very thick-skinned one, that’s for sure, as I was saying just the other day to my old friend and fellow scientifically illiterate denialist nutcase Christopher Booker. Given the choice, I’m sure we’d both be more than happy never to write again on a subject for which we take so much flak. Except we don’t have a choice. Not really. When you’re a journalist and a story comes your way which is screaming to be told and which almost everyone else is ignoring, what option do you have but to fulfil your professional obligations to the truth?

So it is with this ‘hottest year on record’ story. There are several reasons why it doesn’t stand up. The first is that it’s wilfully misleading. You read that headline and you think: ‘Wow! Hottest ever? That is serious.’ But it’s not when you consider the context. ‘On record’ means, in this case, since widespread global thermometer records began — which is as recently as 1880. There have been many, many occasions in history when the earth’s average temperature is reckoned to have been warmer than it is now: in the medieval and Roman warming periods, for example. Indeed, as the Canadian -scientist Dr Tim Ball has calculated by studying the evidence of ice-core data, earth’s recent temperatures rank in the lowest 3 per cent of those recorded since the end of the last ice age 10,000 years ago.

Next is the problem of scientific accuracy. When the Goddard Institute held its press conference to announce the ‘hottest year on record’ claim, the compliant media went to town. For example, Associated Press’s Seth Borenstein — long an assiduous promulgator of the alarmist message — reported that nine of the ten hottest years have occurred since 2000 and that the odds of this happening are about 650 million to one.

Well I’m no statistical genius but even I can work out the flaw with that one: it only works if you assume that every year in history has an equal chance of being hotter or colder. Clearly, though, this is not the case. In the past 150 years we have been emerging from something called the Little Ice Age, so it’s inevitable that the cluster of years at the end of that trend will have a higher likelihood of being warmer than those at the beginning.

And in any case, 2014’s claim to being the warmest on record is at best moot. As Goddard Institute director Gavin Schmidt has since grudgingly conceded, it is impossible to be sure which of the recent years has been warmest because the temperature differences — we’re talking 2/100ths of a degree — are smaller than the margin of error.

But the biggest problem is this, and few journalists are willing to touch it because it opens such a huge can of worms: the surface temperature readings used by and quoted by all the experts mentioned above no longer accurate or trustworthy. When you write this, it invites the obvious question: ‘You’re not seriously arguing, are you, that all the world’s top meteorological institutions are cooking the books because they’ve got the same hidden agenda?’ And instantly you look like a crackpot conspiracy theorist.

There’s plenty of evidence to support it, mind. Exhibit no. 1: the satellite records which, unlike the land-based records, show no rise in temperature in the past 18 years. Exhibit no. 2: the actual raw data from weather stations all over the world. This, it invariably turns out, tells a very different story from the narrative which has been imposed on it by the Keepers of the Flame of the Great Global Warming Scare.

Take the records from Paraguay — one of the countries which according to the Goddard Institute has shown the most marked -warming. Examine the charts on Nasa’s website and they seem to confirm it: all show a clear and steady upward (i.e. warming) trend. Case closed, then? Not quite. A retired accountant called Paul Homewood, blogging at a site called Notalotofpeopleknowthat has tracked down the raw (unadjusted) data. And guess what: they all record a cooling trend, not a warming one.

So why the discrepancy? Simple. The keepers of these temperature datasets have, for some unknown reason, been tinkering with the evidence. Invariably, this has involved adjusting early 20th century temperature records to make them look cooler than they were, and more recent ones hotter. This has happened not just to Paraguay data sets, but also those from countries including the US, China, Russia, Greenland, Australia and New Zealand.

Never has anyone offered any satisfactory explanation for these adjustments. Perhaps it’s about time someone did.