The Age of Global Warming: A History (33 page)

In a joint letter, the presidents of the American Geophysical Union (AGU) and the American Meteorological Society (AMS) claimed that the prospect for scientists having to defend unpopular results in the political arena could well undermine scientific progress and produce ‘tainted results’.
[39]
The editors of
Nature
accused Barton of cherry-picking selected information on the Hockey Stick. ‘Science is, by its very nature, a process open to the questioning and overthrowing of currently accepted ideas, and the detail of Mann and his colleagues’ work has been debated within the climate community,’ the editorial ran, without disclosing that the journal had declined to publish criticisms of Mann’s work in its own pages.
[40]
 

‘My research has been subject to intensive peer review,’ Mann wrote in response to Barton.
[41]
Leshner of the AAAS agreed. The Hockey Stick had been subject to ‘multiple levels of scientific peer review’ to achieve publication, then ‘multiple layers of the IPCC process itself’.
[42]
The presidents of the AGU and AMS called on Congress to respect peer review, ‘this time-tested process of scientific quality control’.
[43]

The issue not mentioned was why peer review had failed to uncover even a fraction of the problems McIntyre had found. The letters from the presidents of the AAAS, the AGU and the AMS demonstrated a stunning lack of intellectual curiosity – wasn’t anyone interested in getting to the bottom of the controversy and finding out for themselves?   

To the British philosopher Roger Scruton, the answer would be self-evident. The strategy of inventing experts backed up by the apparatus of scholarship, research and peer review goes back to the beginnings of the modern university in the Christian and Muslim communities of the Middle Ages. Theology was their foundational discipline and an entirely phoney one:

The purpose of theology has been to generate experts about a topic on which there are no experts, namely God. Built into every version of theology are the foregone conclusions of a faith: conclusions that are not to be questioned but only surrounded with fictitious scholarship and secured against disproof.
[44]

The dispute had escalated beyond Mann and the Hockey Stick. Ultimately it was a question of trust. Should society defer to the collective wisdom of experts or withhold scientific status to statements that cannot be independently verified, the method by which science had escaped the gravitational pull of medieval scholasticism?

In his reply to Barton’s letter, Mann tried to finesse the issue. The key to replication was unfettered access to all the underlying data and the methodologies. And the code, which was the only way of verifying the actual methodology he had used? ‘My computer program is a private piece of intellectual property, as the National Science Foundation and its lawyers recognised.’
[45]
        

In a sense, the person at the centre of the dispute was not Michael Mann, but Stephen McIntyre. It was McIntyre’s insistence on seeing for himself how tree ring data were used to represent a temperature reconstruction that completely revised previous understanding that had led to this clash. ‘Your statement that you have verified something is indifferent to me unless I believe that I could make the verification also,’ Bridgman wrote.
[46]
  Half a century on, Schneider described McIntyre as a ‘serial abuser of legalistic attacks’ for insisting on seeing Mann’s computer code.
[47]
Something had happened to scientific standards in the intervening years.

Ralph Cicerone, president of the National Academy of Sciences (NAS), also wrote to Barton. A former research chemist at the Scripps Institution of Oceanography, now a seasoned Washington insider, Cicerone suggested that the National Academy of Sciences create an independent expert panel to conduct an assessment ‘according to our standard rigorous study process’ to assess Mann’s area of research. ‘Please let us know if we can help,’ Cicerone offered.
[48]
  

Barton wasn’t biting. ‘We can’t evaluate the idea without having seen it, and maybe it’s a darned fine one,’ committee spokesman, Larry Neal, told the
Washington Post
, ‘but an offer that says “Please just go away and leave the science to us, ahem, very intelligent professionals,” is likely to get the response it deserves.’
[49]

Boehlert accepted Cicerone’s offer on behalf of the House Science Committee which in turn empanelled a National Research Council (NRC) chaired by Gerald North, an atmospheric physicist from Texas A&M University. North had no doubt as to the significance of the Hockey Stick. ‘The planet has been cooling slowly until one hundred and twenty years ago, when, bam! It jumps up,’ North told
Science
in 2000. ‘We’ve been breaking our backs on [greenhouse] detection, but I found the one-thousand-year records more convincing than any of our detection studies.’
[50]

Boehlert asked the NAS to examine three issues, specifically mentioning Mann’s work, the validity of criticisms of it and whether the information needed to replicate his work had been made available.
[51]
  Something got lost in translation. The panel’s terms of reference were re-written, dropping any reference to Mann’s work. 

Meanwhile Barton and Ed Whitfield, chairman of the Subcommittee on Oversight and Investigations of the Energy and Commerce Committee, announced the formation of a second panel, led by Edward Wegman, a former chairman of the NAS Committee on Applied and Theoretical Statistics and a Fellow of the Royal Statistical Society, to perform an independent verification of McIntyre and McKitrick’s critique of Mann’s Hockey Stick papers.

In public, leading IPCC figures continued to promote the Hockey Stick. Giving evidence to a House of Lords enquiry in January 2005, Sir John Houghton, who had led Working Group I from 1988 to 2002, asserted that the increase in twentieth-century temperature had been ‘phenomenal’ compared with any variation over the whole millennium.
[52]
   

Privately, some of the leading figures in the IPCC were less sure. The previous October, Tom Wigley, a lead author on the Second Assessment Report and a former director of the University of East Anglia’s Climatic Research Unit, emailed Phil Jones to express his doubts. Replying, Jones certainly believed that the picture of unprecedented twentieth-century warmth was true. There was ‘no way’ that the Medieval Warm Period was as warm as the last twenty years had been, Jones replied. Similarly there was ‘no way’ a whole decade during the Little Ice Age was more than 1
o
C on a global basis cooler than the global average from 1961 to 1990. 

How could he know? These claims weren’t something Jones could objectively demonstrate: ‘This is all gut feeling, no science, but years of experience.’
[53]

In July, Houghton addressed the Senate Energy and Natural Resources Committee. On the basis of two unpublished papers by two of Mann’s colleagues, Caspar Ammann and Eugene Wahl, Houghton claimed ‘the assertions by McIntyre and McKitrick have been shown to be largely false’.
[54]
Concluding his prepared remarks, Houghton said he was optimistic that action to save the world from global warming would be taken. ‘As a Christian, I believe God is committed to his creation and that we have a God-given task of being good stewards of creation – a task that we do not have to accomplish on our own because God is there to help us with it.’
[55]

The reality of Cicerone’s ‘standard rigorous study process’ turned out much as Barton expected. The NRC panel ‘just kind of winged it’, North told a Texas A&M seminar in 2006 – ‘that’s what you do in that kind of expert panel’.
[56]
The panel recommended strip-bark samples, i.e., Graybill’s bristlecones (and foxtails) not be used as proxies in temperature reconstructions. Yet it presented four other temperature reconstructions without checking whether they also used bristlecones (they did).

At the beginning of March 2006, the panel held public hearings. One of the highlights was a presentation by paleo-climatologist Rosanne D’Arrigo. It included a mom-and-apple-pie rendition of the ‘seek and ye shall find’ principle, with a slide headlined ‘Cherry picking’. You have to pick cherries if you want to make cherry pie, an astonished McIntyre recorded in a contemporaneous posting.
[57]
D’Arrigo was as good as her word. For one of her temperature reconstructions, she had used ten out of thirty-six chronologies that had been sampled, retaining only the most ‘temperature-influenced’ ones and binning the rest. ‘If we get a good climatic story from a chronology, we write a paper using it. That is our funded mission,’ D’Arrigo’s co-author, Gordon Jacoby, wrote to Schneider in his capacity as editor of
Climatic Change
.
[58]

Having smelled a rat, North’s panel held its nose. Cherry-picking had become so endemic in paleo-climatology that the practitioners could no longer see – or smell – anything wrong with it. Jan Esper, another tree ring researcher, had written three years before that reducing the number of series could enhance a ‘desired signal’. ‘The ability to pick and choose which samples to use is an advantage unique to dendroclimatology,’ Esper and four others wrote in a peer-reviewed paper.
[59]
Esper’s reconstruction was one of the temperature reconstructions included in the panel’s final report. 

D’Arrigo wasn’t finished. Like Briffa’s, her temperature reconstruction had a decline during the late twentieth century. Panellist Kurt Cuffey of Berkeley picked up on it. ‘Oh, that’s the “Divergence Problem,”’ D’Arrigo responded. Cuffey probed further. How could you rely on these proxies to register past warm periods if they weren’t picking up modern warmth? The matter was being studied, D’Arrigo replied.
[60]

Sitting in the audience, Richard Alley, a glaciologist at Penn State University, noticed the worried look of the panel. He urgently emailed Keith Briffa. The panel’s reaction suggested that ‘they now have serious doubts about tree-rings as paleo-thermometers’ which Alley shared – ‘at least until someone shows me why this divergence really doesn’t matter’.
[61]

The NRC report, published in June, was nuanced and in places surreal. The panel concluded that it could be stated ‘with a high level of confidence’ that the global mean surface temperature during the last few decades of the twentieth century was higher than any comparable period during the preceding four centuries.
[62]
It had less confidence in temperature reconstructions for the prior seven centuries back to AD 900.
[63]

A technical chapter reported McIntyre and McKitrick’s production of hockey sticks from trendless ‘red noise’ using Mann’s standardisation procedures. Mann’s results, the report said, were ‘strongly dependent’ on his statistical methodology. ‘Such issues of robustness need to be taken into account in estimates of statistical uncertainties,’ the report stated – the closest the NRC came to criticising Mann’s methods.
[64]

The panel entered a caveat about its lower confidence in the period before 1600. It had even less confidence in the Hockey Stick’s headline claim that the 1990s was likely to have been the warmest decade and 1998 the warmest year in at least a millennium.
[65]
However, it declared that surface temperature reconstructions were no longer considered ‘primary evidence’.
[66]
Instead climate model simulations showed that ‘estimated temperature variation’ in the two thousand years before the Industrial Revolution could be plausibly explained by estimated variations in solar radiation and volcanic activities.
[67]

How could the panel be so sure of the reliability of these estimates? They couldn’t. 

Data for natural forcings such as changes in solar radiation and volcanoes came largely from the same sources as the proxy evidence for surface temperature variations.
[68]
‘These reconstructions are typically associated with as much uncertainty as reconstructions of surface temperature,’ the report explained.
[69]

The
New York Times
reported the Hockey Stick had been endorsed ‘with a few reservations’.
[70]
Mann professed himself ‘very happy’.
[71]
Asked about Mann and his co-authors’ work, North replied, ‘We roughly agree with the substance of their findings.’ But Kurt Cuffey said the prominence the IPCC had given the Hockey Stick ‘sent a very misleading message about how resolved this part of the scientific research was’. Statistician Peter Bloomfield commented that he’d seen ‘nothing that spoke to me of any manipulation’.
[72]

Cicerone penned the report’s opening sentence: ‘Our understanding of climate and how it has varied over time is advancing rapidly as new data are acquired and new investigative instruments and methods are employed’ – a sentiment that conforms to the narrative of a linear, cumulative advance of scientific knowledge.
[73]
As far as the development of theories went, Kuhn argued that this view was not supported by the history of science.

Empirical evidence should be different. Previously accepted facts about the Medieval Warm Period and the Little Ice Age gave way to new facts to fit an agenda-driven science.

Three weeks after the NRC reported, Barton released the Wegman report. Its language was as sharp as the NRC’s was nuanced. Mann’s work was ‘somewhat obscure and incomplete’. McIntyre and McKitrick’s criticisms were ‘valid and compelling’.
[74]
There was no evidence that Mann or any of the other authors in paleo-climatology studies had ‘significant interactions with mainstream statisticians’.
[75]

The isolation of the paleo-climate community was reinforced by a dense social network of authors and over-reliance on peer review ‘which was not necessarily independent’.
[76]
Politicisation of their work meant that the paleo-climate community could hardly reassess their public positions without losing credibility. Mann’s claim that the 1990s was the hottest decade of the millennium and that 1998 was the hottest year of the millennium ‘cannot be supported by his analysis’.
[77]

At a congressional subcommittee hearing on 19
th
July, first Wegman then North were questioned on their reports. 

Barton asked North whether he disputed Wegman’s conclusions or methodology. ‘No, we don’t. We don’t disagree with their criticism. In fact, pretty much the same thing is said in our report,’ North replied. This didn’t mean the conclusions were false – ‘It happens all the time in science,’ North added.
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