Articles in the Mail on Sunday show the same uncritical reliance on dodgy sources that caused David Rose's catastrophic mistakes about Iraq

You can divide people into two categories: those who learn from their mistakes and those who don't. There is no third category: we all mess up from time to time.

Journalism is a mistake waiting to happen. With tight deadlines, big rewards for shock and awe and small rewards for methodical, less spectacular work, with an inverse relationship between volume and truth in public life, reporters tend to stumble from one accident to another.

The only hope journalists have of retaining any kind of self-respect is to question themselves repeatedly, ask whether they are being manipulated and whether they are seeing the whole story. So where does this leave David Rose?

I don't want to credit the media with more power than it has, but from time to time it is pivotal to public policy. One such moment was the build-up to the Iraq war. The UK might not have joined Bush's war if it didn't have broad support from the press, and particularly from sections of the liberal press.

The Observer was more influential in the build-up to the war than any other outlet, as the position it took – strongly in favour – was so unexpected. Its editorial line caused huge ructions within the paper and plenty of conflict with journalists at its sister-paper the Guardian (I'm painfully aware of this, having had a shouting match with the Observer's then political editor, Kamal Ahmed, in the building's stairwell). It also emboldened some wavering Labour MPs and helped Tony Blair make his case.

The Observer's position was strongly influenced by Rose's reporting. Though others warned that his sources should not be trusted, Rose's articles for the paper uncritically reported the claims made by Ahmed Chalabi and the Iraqi National Congress about Saddam Hussein's alleged weapons of mass destruction. Chalabi later admitted that they were incorrect.

The chain of causality is a long one, and I don't want to pull on it too hard, but it is arguable that the Observer could not have sustained its position were it not for Rose's reporting; that Blair could not have contained the Labour revolt were it not for the Observer; and that Bush could not have gone to war were it not for Blair's support.

In May 2004, over a year after the war began, Rose, to his credit, admitted that he'd got it wrong. By then, of course, it was far too late to undo the damage. He wrote a partial apology in an article titled: "Iraqi defectors tricked us with WMD lies, but we must not be fooled again".

A vain hope. Admitting it, it seems, is one thing; learning from it quite another.

Since the Iraq debacle, Rose has latterly been writing articles attacking climate science for the Daily Mail. He has distinguished himself by the same uncritical reliance on dodgy sources that caused his catastrophic mistakes about Iraq.

But now he has published his longest list of errors yet, in an article in the Mail on Sunday. Every one of them would have been easy to check and disprove, had he been inclined to do so. But the Mail pays well for this crap, and checking, under these circumstances, is likely to be an expensive pastime.

I don't have time to deal with every one of the mistakes his article contains – it takes 100 times as long to show why a claim is wrong as it does to make it – but here's a quick breakdown, beginning with the first sentence: (I've been able to pull this together with the help of the Climate Science Rapid Response Team, which put me in touch with the relevant scientists and pointed me to the primary datasets.)

Rose:

"A year ago tomorrow, just before the opening of the UN Copenhagen world climate summit, the British Meteorological Office issued a confident prediction. The mean world temperature for 2010, it announced, 'is expected to be 14.58C, the warmest on record' – a deeply worrying 0.58C above the 1961-1990 average."

"A year ago tomorrow" would have been 7 December. The Met Office issued its forecast (not a "prediction") on 10 December.

And there was nothing "confident" about it. The press release said that a record warm year "is not a certainty, especially if the current El Niño was to unexpectedly decline rapidly near the start of 2010, or if there was a large volcanic eruption." As it happened, El Niño did decline rapidly, and was replaced by a very strong La Niña.

Rose:

"Met Office officials openly boasted that they hoped by their statements to persuade the Copenhagen gathering to impose new and stringent carbon emission limits - an ambition that was not to be met."

Rose provides no source for this claim (or for any of the claims here). The Met Office tells me it was not trying to influence policy, simply to report the facts.

Rose:

"Climate science orthodoxy, as promulgated by bodies such as the UN Intergovernmental Panel on Climate Change (IPCC) and the University of East Anglia Climatic Research Unit (CRU), says that temperatures have risen and will continue to rise in step with increasing CO 2 in the atmosphere"

I challenge Rose to find a single occasion on which these bodies have said that temperatures will rise "in step" with CO 2 . As Professor Kevin Trenberth of the National Center for Atmospheric Research tells me: "One should not be misled by seizing on an individual value or year and citing trends for that, because natural variability such as from El Niño creates ups and downs all the time."

Does Rose expect warming to proceed along a straight line?

Rose:

"Last week at Cancún, in an attempt to influence richer countries to agree to give £20bn immediately to poorer ones to offset the results of warming, the US-based International Food Policy Research Institute warned that global temperatures would be 6.5C higher by 2100, leading to rocketing food prices and a decline in production."

I can find no evidence at all for this. The Institute did release a report last week, but it doesn't even mention 6.5C, let alone predict that temperatures would climb to that point. In fact it makes no predictions whatever about global warming: it simply explains what is likely to happen to agriculture at different temperature scenarios, none of which extend as far as 6.5C. It is not easy to see how Rose could have got this so wrong.

Rose:

"Actually, with the exception of 1998 – a 'blip' year when temperatures spiked because of a strong El Niño effect (the cyclical warming of the southern Pacific that affects weather around the world) – the data on the Met Office's and CRU's own websites show that global temperatures have been flat, not for 10, but for the past 15 years."

All the datasets, including the Met Office/CRU figures show that the current decade is the warmest in the instrumental record.

Rose:

"They go up a bit, then down a bit, but those small rises and falls amount to less than their measuring system's acknowledged margin of error. They have no statistical significance and reveal no evidence of any trend at all."

Professor Phil Jones at the University of East Anglia (yes, the Phil Jones), tells me: "The error of estimate of global averages or the forecasts for subsequent years is completely unrelated to the trend of warming. This is comparing apples with oranges."

Rose:

"Last year it predicted that the 2010 average would be 14.58C. Last week, this had been reduced to 14.52C. That may not sound like much. But when one considers that by the Met Office's own account, the total rise in world temperatures since the 1850s has been less than 0.8C, it is quite a big deal. Above all, it means the trend stays flat."

In fact 14.52C (which means 0.52C above the long-term average) is equal to the record set in 1998. The Met Office figures show that – for January-October – 2010 is the equal warmest year on record. The National Oceanic and Atmospheric Administration (NOAA) and Nasa databases, which record anomalies of 0.54C and 0.58C respectively, suggest that so far it's the warmest year on record.

Phil Jones tells me:

"The forecast of 14.58 for 2010 was well within the error range if the final number was 14.52. The difference is 0.06 and the error range is +/- 0.10 approx".

Rose:

"Meanwhile, according to an analysis yesterday by David Whitehouse of the Global Warming Policy Foundation, 2010 had only two unusually warm months, March and April, when El Niño was at its peak."

This, again, is utter nonsense, and goes to show what happens when you rely on untrustworthy sources. As you can see from all three global datasets (CRU, NOAA and Nasa) all the months this year for which the data has so far been collated (January-October) were anomalously warm.

Phil Jones points out: "Looking at these, it is clear that they have used the land-only values!!!!!!"

Amazing. I can't imagine what the fuss would have been like if climate scientists had made the same mistake as the Global Warming Policy Foundation has done.

Rose:

"The data from October to the end of the year suggests that when the final figure is computed, 2010 will not be the warmest year at all, but at most the third warmest, behind both 1998 and 2005."

Perhaps Rose could explain how he has obtained the data from October to the end of the year. Is he employing Mystic Meg as his researcher?

Rose:

"Earlier this year, a paper by Michael Mann – for years a leading light in the IPCC, and the author of the infamous 'hockey stick graph' showing flat temperatures for 2,000 years until the recent dizzying increase - made an extraordinary admission: that, as his critics had always claimed, there had indeed been a ' medieval warm period' around 1,000AD, when the world may well have been hotter than it is now."

Rose, as usual, provides no reference for this paper, and none of the scientists I've contacted, including Mann, has any idea what he's talking about. But Mann points out that neither "we, nor any other researchers, have ever denied there was a period of relative warmth sometime during medieval for many regions. What we – and other competent researchers – have all found is that the warmth was far more regional than modern warmth, with some large regions, like the tropical Pacific, having been unusually *cold* at the time, and when you average over the globe, the warmth of the medieval warm period/medieval climate anomaly simply doesn't reach modern warmth. Every peer-reviewed scientific study of the matter comes to the same conclusions."

Rose:

"Other research is beginning to show that cyclical changes in water vapour – a much more powerful greenhouse gas than carbon dioxide – may account for much of the 20th-century warming."

Andrew Dessler of Texas A&M University says: "I have no idea what "research" they are talking about." Dessler recently analysed of all the data and showed that there is no evidence for such claims.

Dessler continues: "This is really a classic "sceptic" argument. When it was originally brought up in the early 1990s, it was a legitimate uncertainty in our understanding. Scientists, however, view uncertainty like a starving wolf views red meat, and so the problem was thoroughly attacked over the next 15 years. In particular, about eight years ago, Nasa launched the atmospheric infrared sounder on board the Aqua satellite, which measures water vapour distribution with great accuracy. These data have really settled the question. However, just like the monster in a horror movie, this argument just won't die."

Anthony del Genio of Nasa also tells me: "I know of no evidence for the statement that cyclical changes in water vapour are responsible for much of the 20th-century warming, unless there is a new paper of which I am not aware that makes such a claim."

He continues: "The important thing is that the inter-annual changes of water vapour and everything else associated with El Niño are not systematic long-term variations, rather they go up and down every two to five years or so. So they don't cause a long-term trend. CO 2 changes, however, do cause long-term changes in CO 2 . Because CO 2 is itself a greenhouse gas, it warms the atmosphere and surface of the planet, which causes more water to evaporate from the oceans and build up in the atmosphere. The resulting warming due to the water vapour is in fact larger than the initial warming due to the CO 2 that forced it to happen, and this is the point of the Lacis paper - yes, water vapour is a more important greenhouse gas than CO 2 , but water vapour doesn't change systematically with time UNLESS CO 2 is changing and initiating a warming that sets into motion the surface and atmospheric processes that allow water vapour to systematically increase. So CO 2 changes are the root cause of whatever water vapour feedback winds up occurring."

Rose:

"Even Phil Jones, the CRU director at the centre of last year's 'Climategate' leaked email scandal, was forced to admit in a little-noticed BBC online interview that there has been 'no statistically significant warming' since 1995."

Phil Jones replies: "The key statement here is 'not statistically significant'. It wasn't for these years at the 95% level, but it would have been at the 90% level. If you add the value of 0.52 in for 2010 and look at 1995 to 2010 then the warming is statistically significant at the 95% level." [What this means is that the warming trend for the past few years previously met a lower test of statistical significance. With addition of the results so far for 2010, it now means the higher test.]

Rose:

"One of those leaked emails, dated October 2009, was from Kevin Trenberth, head of climate analysis at the US government's National Centre for Atmospheric Research and the IPCC's lead author on climate change science in its monumental 2002 and 2007 reports. He wrote: 'The fact is that we can't account for the lack of warming at the moment, and it is a travesty that we can't.'"

Here's what Trenberth says on his website:

"It is amazing to see this particular quote lambasted so often. It stems from a paper I published this year bemoaning our inability to effectively monitor the energy flows associated with short- term climate variability. It is quite clear from the paper that I was not questioning the link between anthropogenic greenhouse gas emissions and warming, or even suggesting that recent temperatures are unusual in the context of short-term natural variability."

It is hard to believe that Rose was unaware of this explanation.

Rose:

"The question now emerging for climate scientists and policymakers alike is very simple. Just how long does a pause have to be before the thesis that the world is getting hotter because of human activity starts to collapse?"

The question now emerging for Rose is very simple. Just how many mistakes does he have to make before the thesis that these are innocent errors starts to collapse?

www.monbiot.com

• On 8 December we amended this article to take out links to third party content. We incorrectly referred to Rose's article running in the Daily Mail. This has been corrected.