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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.

December 14, 2009 - Posted by aletho | Deception, Science and Pseudo-Science, Timeless or most popular