ClimateGate: A closer look at some of the 'tricks' by the email authors

David Rose | Mail Online | December 13, 2009

The claim was both simple and terrifying: that temperatures on planet Earth are now ‘likely the highest in at least the past 1,300 years’. As its authors from the United Nations Intergovernmental Panel on Climate Change (IPCC) must have expected, it made headlines around the world.

Yet some of the scientists who helped to draft it, The Mail on Sunday can reveal, harboured uncomfortable doubts. In the words of one, David Rind from the US space agency Nasa, it ‘looks like there were years around 1000AD that could have been just as warm’.

Keith Briffa from the University of East Anglia’s Climatic Research Unit (CRU), which plays a key role in forming IPCC assessments, urged caution, warning that when it came to historical climate records, there was no new data, only the ‘same old evidence’ that had been around for years.

‘Let us not try to over-egg the pudding,’ he wrote in an email to an IPCC colleague in September 2006. ‘True, there have been many different techniques used to aggregate and scale data – but the efficacy of these is still far from established.’

But when the ‘warmest for 1,300 years’ claim was published in 2007 in the IPCC’s fourth report, the doubters kept silent.

It is only now that their concerns have started to emerge from the thousands of pages of ‘Warmergate’ emails leaked last month from the CRU’s computers, along with references to performing a ‘trick’ to ‘hide’ temperature decline and instructions to resist all efforts by the CRU’s critics to use the Freedom of Information Act to check the unit’s data and conclusions.

Last week, as an official inquiry by the former civil servant Sir Muir Russell began, I tried to assess Warmergate’s wider significance.

The CRU’s supporters insisted it was limited. ‘In the long term, it will make very little difference to the scientific consensus, and to the way politicians respond to it,’ Professor Trevor Davies, the university’s Pro-Vice Chancellor and a former CRU director, told me. ‘I am certain that the science is rock solid.’

He admitted that his CRU colleagues had sometimes used ‘injudicious phrases’, but that was because they kept on being ‘diverted’ from their work by those who wished to scrutinise it. ‘It’s understandable that sometimes people get frustrated,’ he said.

The only lesson the affair had for him was that ‘we have got to get better in terms of explanation. Some scientists still find it quite it difficult to communicate with the public.’

Others, however, were less optimistic. Roger Pielke, Professor of Environmental Studies at the University of Colorado, could in no sense be described as a climate change sceptic, let alone a ‘denier’.

‘Human-caused climate change is real, and I’m a strong advocate for action,’ he said. ‘But I’m also a strong advocate for integrity in science.’

Pielke’s verdict on the scandal is damning.

‘These emails open up the possibility that big scientific questions we’ve regarded as settled may need another look. They reveal that some of these scientists saw themselves not as neutral investigators but as warriors engaged in battle with the so-called sceptics.

‘They have lost a lot of credibility and as far as their being leading spokespeople on this issue of huge public importance, there is no going back.’

Climate science is complicated, and often the only way to make sense of raw data is through sophisticated statistical computer programs. The consequence is that most lay individuals – politicians and members of the public alike – have little choice but to take the assurances of scientists such as Davies on trust.

He and other ‘global warmists’ often insist that when it comes to the IPCC’s main conclusions – that the Earth is in a period of potentially catastrophic warming and that the main culprit is man-made greenhouse gas emission – no serious scientist dissents from the conventional view.

Hence, perhaps, Gordon Brown’s recent comment that those who disagree are ‘behind-the-times, antiscience, flat-Earth climate sceptics’.

In fact, there is a large body of highly-respected academic experts who fiercely contest this thesis: people such as Richard Lindzen, Professor of Meteorology at the Massachusetts Institute of Technology and a disillusioned former IPCC member, and Dr Tom Segalstad, head of geology at Oslo University, who has stated that ‘most leading geologists throughout the world know that the IPCC’s view of Earth processes are implausible if not impossible’.

These dissenters focus their criticisms on the IPCC’s analysis of the way the atmosphere works and the models it uses to predict the future.

However, Warmergate strikes at something more fundamental – the science that justifies the basic assumption that the present warming really is unprecedented, at least in the past few thousand years.

Take the now-notorious email that the CRU’s currently suspended director, Dr Phil Jones, sent to his IPCC colleagues on November 16, 1999, when he wrote he had ‘just completed Mike’s Nature trick’ and had so managed to ‘hide the decline’.

The CRU’s supporters have protested bitterly about the attention paid to this message. In the course of an extraordinary BBC interview in which he called an American critic an ‘****hole’ live on air, Jones’s colleague Professor Andrew Watson insisted that the fuss was completely unjustified, because all Jones had been talking about was ‘tweaking a diagram’.

Davies told me that the email had been ‘taken out of context’ adding: ‘One definition of the word “trick” is “the best way of doing something”. What Phil did was standard practice and the facts are out there in the peer-reviewed literature.’

However, the full context of that ‘trick’ email, as shown by a new and until now unreported analysis by the Canadian climate statistician Steve McIntyre, is extremely troubling. Derived from close examination of some of the thousands of other leaked emails, he says it suggests the ‘trick’ undermines not only the CRU but the IPCC.

There is a widespread misconception that the ‘decline’ Jones was referring to is the fall in global temperatures from their peak in 1998, which probably was the hottest year for a long time. In fact, its subject was more technical – and much more significant.

It is true that, in Watson’s phrase, in the autumn of 1999 Jones and his colleagues were trying to ‘tweak’ a diagram. But it wasn’t just any old diagram.

It was the chart displayed on the first page of the ‘Summary for Policymakers’ of the 2001 IPCC report – the famous ‘hockey stick’ graph that has been endlessly reproduced in everything from newspapers to primary-school textbooks ever since, showing centuries of level or declining temperatures until a dizzying, almost vertical rise in the late 20th Century.

There could be no simpler or more dramatic representation of global warming, and if the origin of worldwide concern over climate change could be traced to a single image, it would be the hockey stick. Drawing a diagram such as this is far from straightforward.

Gabriel Fahrenheit did not invent the mercury thermometer until 1724, so scientists who want to reconstruct earlier climate history have to use ‘proxy data’ – measurements derived from records such as ice cores, tree-rings and growing season dates.

However, different proxies give very different results.

For example, some suggest that the ‘medieval warm period’, the 350-year era that started around 1000, when red wine grapes flourished in southern England and the Vikings tilled now-frozen farms in Greenland, was considerably warmer than even 1998.

Of course, this is inconvenient to climate change believers because there were no cars or factories pumping out greenhouse gases in 1000AD – yet the Earth still warmed.

Some tree-ring data eliminates the medieval warmth altogether, while others reflect it. In September 1999, Jones’s IPCC colleague Michael Mann of Penn State University in America – who is now also the subject of an official investigation –was working with Jones on the hockey stick. As they debated which data to use, they discussed a long tree-ring analysis carried out by Keith Briffa.

Briffa knew exactly why they wanted it, writing in an email on September 22: ‘I know there is pressure to present a nice tidy story as regards “apparent unprecedented warming in a thousand years or more”.’ But his conscience was troubled. ‘In reality the situation is not quite so simple – I believe that the recent warmth was probably matched about 1,000 years ago.’

Another British scientist – Chris Folland of the Met Office’s Hadley Centre – wrote the same day that using Briffa’s data might be awkward, because it suggested the past was too warm. This, he lamented, ‘dilutes the message rather significantly’.

Over the next few days, Briffa, Jones, Folland and Mann emailed each other furiously. Mann was fearful that if Briffa’s trees made the IPCC diagram, ‘the sceptics [would] have a field day casting doubt on our ability to understand the factors that influence these estimates and, thus, can undermine faith [in them] – I don’t think that doubt is scientifically justified, and I’d hate to be the one to have to give it fodder!’

Finally, Briffa changed the way he computed his data and submitted a revised version. This brought his work into line for earlier centuries, and ‘cooled’ them significantly. But alas, it created another, potentially even more serious, problem.

According to his tree rings, the period since 1960 had not seen a steep rise in temperature, as actual temperature readings showed – but a large and steady decline, so calling into question the accuracy of the earlier data derived from tree rings.

This is the context in which, seven weeks later, Jones presented his ‘trick’ – as simple as it was deceptive.

All he had to do was cut off Briffa’s inconvenient data at the point where the decline started, in 1961, and replace it with actual temperature readings, which showed an increase. On the hockey stick graph, his line is abruptly terminated – but the end of the line is obscured by the other lines.

Any scientist ought to know that you just can’t mix and match proxy and actual data,’ said Philip Stott, emeritus professor of biogeography at London’s School of Oriental and African Studies. ‘They’re apples and oranges. Yet that’s exactly what he did.’

Since Warmergate-broke, some of the CRU’s supporters have claimed that Jones and his colleagues made a ‘full disclosure’ of what they did to Briffa’s data in order to produce the hockey stick.

But as McIntyre points out, ‘contrary to claims by various climate scientists, the IPCC Third Assessment Report did not disclose the deletion of the post-1960 values’. On the final diagram, the cut off was simply concealed by the other lines.

By 2007, when the IPCC produced its fourth report, McIntyre had become aware of the manipulation of the Briffa data and Briffa himself, as shown at the start of this article, continued to have serious qualms. McIntyre by now was an IPCC ‘reviewer’ and he urged the IPCC not to delete the post-1961 data in its 2007 graph. ‘They refused,’ he said, ‘stating this would be “inappropriate”.’

Yet even this, Pielke told me, may not ultimately be the biggest consequence of Warmergate.

Some of the most controversial leaked emails concern attempts by Jones and his colleagues to avoid disclosure of the CRU’s temperature database – its vast library of readings from more than 1,000 weather stations around the world, the ultimate resource that records how temperatures have changed.

In one email from 2005, Jones warned Mann not to leave such data lying around on searchable websites, because ‘you never know who is trawling them’.

Critics such as McIntyre had been ‘after the CRU station data for years. If they ever hear there is a Freedom of Information Act now in the UK, I think I’ll delete the file rather than send to anyone’.

Yesterday Davies said that, contrary to some reports, none of this data has in fact been deleted. But in the wake of the scandal, its reliability too is up for grabs.

The problem is that, just like tree rings or ice cores, readings from thermometers or electronic ‘thermistors’ are open to interpretation.

The sites of weather stations that were once open countryside become built up areas, so trapping heat, and the type of equipment used changes over time. The result is what climate scientists call ‘inhomogeneities’ – anomalies between readings that need to be ‘adjusted’.

But can we trust the way such ‘adjustments’ are made?

Last week, an article posted on a popular climate sceptic website analysed the data from the past 130 years in Darwin, Australia.

This suggested that average temperatures had risen there by about two degrees Celsius. However, the raw data had been ‘adjusted’ in a series of abrupt upward steps by exactly the same amount: without the adjustment, the Darwin temperature record would have stayed level.

In 2007, McIntyre examined records across America. He found that between 1999 and 2007, the US equivalent of the Met Office had changed the way it adjusted old data.

The result was to make the Thirties seem cooler, and the years since 1990 much warmer. Previously, the warmest year since records began in America had been 1934.

Now, in line with CRU and IPCC orthodoxy, it was 1998.

At the CRU, said Davies, some stations’ readings were adjusted by unit and in such cases, raw and adjusted data could be compared. But in about 90 per cent of cases, the adjustment was carried out in the countries that collected the data, and the CRU would not know exactly how this had been done.

Davies said: ‘All I can say is that the process is careful and considered. To get the details, the best way would be to go the various national meteorological services.’

The consequences of that, Stott said, may be explosive. ‘If you take Darwin, the gap between the two just looks too big. If that applies elsewhere, it’s going to get really interesting. It’s no longer going to be good enough for the Met Office and CRU to put the data out there.

‘To know we can trust it, we’ve got to know what adjustments have been made, and why.’

Last week, at the Copenhagen climate summit, the Met Office said that the Nineties have been the warmest decade in history. Depending on how the data has been adjusted, Stott said, that statement may not be true.

Pielke agreed. ‘After Climategate, the surface temperature record is being called into question.’ To experts such as McIntyre and Pielke, perhaps the most baffling thing has been the near-unanimity over global warming in the world’s mainstream media – a unanimity much greater than that found among scientists.

In part, this is the result of strongarm tactics.

For example, last year the BBC environment reporter Roger Harrabin made substantial changes to an article on the corporation website that asked why global warming seemed to have stalled since 1998 – caving in to direct pressure from a climate change activist, Jo Abbess.

‘Personally, I think it is highly irresponsible to play into the hands of the sceptics who continually promote the idea that “global warming finished in 1998″ when that is so patently not true,’ she told him in an email.

After a brief exchange, he complied and sent a final note: ‘Have a look in ten minutes and tell me you are happier. We have changed headline and more.’

Afterwards, Abbess boasted on her website: ‘Climate Changers, Remember to challenge any piece of media that seems like it’s been subject to spin or scepticism. Here’s my go for today. The BBC actually changed an article I requested a correction for.’

Last week, Michael Schlesinger, Professor of Atmospheric Studies at the University of Illinois, sent a still cruder threat to Andrew Revkin of the New York Times, accusing him of ‘gutter reportage’, and warning: ‘The vibe that I am getting from here, there and everywhere is that your reportage is very worrisome to most climate scientists … I sense that you are about to experience the “Big Cutoff” from those of us who believe we can no longer trust you, me included.’

But in the wake of Warmergate, such threats – and the readiness to bow to them – may become rarer.

‘A year ago, if a reporter called me, all I got was questions about why I’m trying to deny climate change and am threatening the future of the planet,’ said Professor Ross McKitrick of Guelph University near Toronto, a long-time collaborator with McIntyre.

‘Now, I’m getting questions about how they did the hockey stick and the problems with the data. Maybe the emails have started to open people’s eyes.’

Russian secret service agents admitted yesterday that the hacked ‘Warmergate’ emails were uploaded on a Siberian internet server, but strenuously denied a clandestine state-sponsored operation to wreck the Copenhagen summit.

The FSB – formerly the KGB – confirmed that thousands of messages to and from scientists at the University of East Anglia’s Climatic Research Unit were distributed to the world from the city of Tomsk, as revealed by The Mail on Sunday last week.

Now, it has emerged that IT experts specialising in hacking techniques were brought in by the Russian authorities following this newspaper’s exposure of the Tomsk link. They have gathered evidence about how and where the operation was carried out, although they are not prepared to say at this stage who they think was responsible.

A Russian intelligence source claimed the FSB had new information which could cast light on who was behind the elaborate operation.

‘We are not prepared to release details, but we might if the false claims about the FSB’s involvement do not stop,’ he said. ‘The emails were uploaded to the Tomsk server but we are sure this was done from outside Russia.’

The Kremlin’s top climate change official, Alexander Bedritsky, denied the Russian government was involved in breaking into the CRU’s computer system.

‘You can post information on a computer from any other country. It is nonsense to blame Russia,’ he said.

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