The Mann libel case has been attracting increasing commentary, including from people outside the climate community. Integral to Mann’s litigation are representations that he was “investigated” by 6-9 investigations, all of which supposedly gave him “exonerations” on wide-ranging counts, including “scientific misconduct”, “fraud”, “academic fraud”, “data falsification”, “statistical manipulation”, “manipulation of data” and even supposed findings that his work was “properly conducted an fairly presented”. Mann also represented that these investigations were widely covered in international and national media and thus known to Steyn and the other defendants.

In today’s post, I’ll look closely at the Oxburgh panel, one of the investigations cited in Mann’s pleadings. However, contrary to the claims in Mann’s litigation, not only did the Oxburgh panel not exonerate Mann, at their press conference, Oxburgh panelist David Hand, then President of the Royal Statistical Society, made very disparaging and critical comments about Mann’s work, describing it as based on “inappropriate” statistics that led to “exaggerated” results. These comments were widely reported in international media, later covered in a CEI article that, in turn, was reported by National Review. Moreover, information obtained from FOI in the UK a couple of years ago shows that Mann objected vehemently to criticism from Oxburgh panelist, which he characterized as a “rogue opinion” and unsuccessfully sought a public apology.

Mann’s claim that the Oxburgh panel “exonerated” Mann on counts ranging from scientific misconduct to statistical manipulation to proper conduct and fair presentation of results has no more validity than his claim to have been awarded a Nobel prize for his supposedly seminal work “document[ing] the steady rise in surface temperatures during the 20th Century and the steep increase in measured temperatures since the 1950s.”

The “Investigations” in the Pleadings

Mann’s pleadings are extremely prolix and the precise scope of his supposed exoneration varies somewhat from paragraph to paragraph.

In paragraph 21 of the Complaint, Mann claimed that there had been “separate and independent” investigations by Penn State and UEA (two each) and by five government agencies into misconduct by “Mann and colleagues” and that all nine found no basis to allegations of “scientific misconduct or manipulation of data”:

21. Following the publication of the CRU emails, Penn State and the University of East Anglia (in four separate instances) and five governmental agencies [listed] have conducted separate and independent investigations into the allegations of scientific misconduct against Dr. Mann and his colleagues. Every one of these investigations has reached the same conclusion: there is no basis to any of the allegations of scientific misconduct or manipulation of data.

As an editorial comment, the terms “scientific misconduct” and “manipulation of data” have quite different meanings. For example, Barry Bickmore, a Mann supporter, observed: “If you had any knowledge about how to handle data, you would realize that scientists always “manipulate” data.” Bickmore’s observation would appear to be inconsistent with the supposed findings of the inquiries on this point.

In paragraph 3 of the Complaint, Mann characterized the findings of “all” the investigations in somewhat different terms, saying that these ‘academic institutions and governmental entities” (which, by very strong implication, are the 9 investigations later itemized in paragraph 21) conducted investigation into “Dr. Mann’s work” (not his colleagues) and found no basis to allegations of “academic fraud” in addition to supposed exoneration of “scientific misconduct” and “manipulation of data” as subsequently claimed. They also claim that “every such investigation” “concluded” that Mann’s research and conclusions were “properly conducted and fairly presented”. Actually more than that – they also claimed this of “every replication”, a counterintuitive characterization of the work of McIntyre and McKitrick, McShane and Wyner and the Wegman Report, to mention only a few.

3… In response to these accusations, academic institutions and governmental entities alike… have conducted investigations into Dr. Mann’s work, and found the allegations of academic fraud to be baseless. Every such investigation- and every replication of Dr. Mann’s work has concluded that Dr. Mann’s research and conclusions were properly conducted and fairly presented.

In paragraph 24, Mann further states that “all” of the investigations found “no evidence of any fraud, data falsification, statistical manipulation, or misconduct of any kind by Dr. Mann”. In making this declaration, they emphasized that these findings were “widely available and commented upon in the national and international media”, a point that is of particular interest when we examine contemporary reports of the Oxburgh panel.

24. All of the above investigations found that there was no evidence of any fraud, data falsification, statistical manipulation, or misconduct of any kind by Dr. Mann. All of the above reports and publications were widely available and commented upon in the national and international media. All were read by the Defendants. To the extent there was ever any question regarding the propriety of Dr. Mann’s research, it was laid to rest as a result of these investigations.

Combining the different assertions, Mann claimed that “all” of the investigations exonerated him of the following: scientific misconduct, fraud, academic fraud, data falsification, statistical manipulation, manipulation of data and even supposed findings that his work was “properly conducted an fairly presented”.

CEI/NR Memoranda and Mann Reply

In the CEI memorandum of December 14, 2012, CEI contested Mann’s characterization of the findings of the various investigations, pointing out that Mann had failed to provide supporting quotations from seven of the investigations and contested whether the excerpts from the other two contradicted the statements in dispute (page 18):

Indeed, the Complaint fails to quote a single word or cite a single page from seven of those reports, and the brief excerpts of two that it does set forth do not actually contradict any of the CEI Defendants’ challenged statements. Compare Compl. ¶¶22-23 with Compl. ¶26.

In respect to the Oxburgh report under analysis today, Mann’s reply memorandum of January 2013 provided a single excerpt of the Oxburgh report, but this excerpt referred only to CRU without providing any form of exoneration to Mann:

In April 2010, the University of East Anglia convened an international Scientific Assessment Panel, in consultation with the Royal Society of London for Improving Natural Knowledge, 38 and chaired by Professor Ron Oxburgh. The Report of the International Panel assessed the integrity of the research published by the CRU and found “no evidence of any deliberate scientific malpractice in any of the work of the Climatic Research Unit”. 39

NR Reply Memorandum

{paragraph added Feb 19, 2014] The National Review Reply Memorandum of Feb 1, 2013 explicitly mentioned Hand’s critique in their summary of the Oxburgh report as follows:

Similarly, the Oxburgh report, cited by Mann (Pl.’s Resp. at 19) as evidence of his “exoneration,” examined only the conduct of East Anglia Climate Research Unit scientists, not Mann. Nonetheless, the panel concluded that it was “regrettable” that tree-ring proxy reconstructions “by the IPCC and others” neglected to emphasize “the discrepancy between instrumental and tree-based proxy reconstructions of temperature during the late 20th century.” See Pl.’s Resp., Ex. 5 at 5 ¶ 7. Prof. David Hand, the head of the Royal Statistical Society and a member of the panel, subsequently singled out Michael Mann’s research for criticism, noting that Mann’s used “inappropriate methods” that “exaggerated the size of the blade at the end of the hockey stick.” See Supp. Coffin Decl., Ex. H. The panel, though not Prof. Hand, later clarified that its report had not charged any scientists with being “deliberately misleading” in their analyses.

The Oxburgh Report and Press Conference

Turning now to the facts.

In February 2010, with the Muir Russell panel making negligible progess, East Anglia formed a second panel, which Vice Chancellor Acton told the Parliamentary Committee would appraise CRU’s science.

The University commissioned Oxburgh and his “Scientific Appraisal Panel”, which interpreted its terms of reference as the examination of a list of 11 academic articles selected by the University of East Anglia (though the list was represented to the panel as being selected by the Royal Society). The list included three CRU articles presenting variations of the Briffa MXD reconstruction that had originated the hide-the-decline controversy. Two of the three articles – both from 1998 – unambiguously showed the decline in the Briffa reconstruction. (Indeed, it was the inconsistency between these articles and the IPCC diagram that had originally occasioned my interest.)

However, both these articles were prior to the unsavory discussion among Mann and other IPCC authors in which senior IPCC officials expressed their concern that inclusion of the Briffa reconstruction might “dilute the message”, with Mann readily acquiescing because he did not want to give “fodder to the skeptics” (see CA summary here). Subsequent to this discussion, CRU sent Mann a Briffa version showing the decline (this version was then unpublished and not published until Briffa et al 2001). CRU later sent Mann a version in which data was deleted after 1960. Briffa et al 2001 was the third relevant article considered by Oxburgh. It showed the decline in all figures in which the reconstruction was showed individually, but in the figure comparing the reconstruction to other reconstructions (Plate 3), it truncated the data, as had already been done at IPCC. This sequence is relevant for other discussions: in this case, IPCC did not merely assess published literature; the published literature was affected by IPCC requirements.

The Oxburgh panel had only the following short report on these issues:

7. Recent public discussion of climate change and summaries and popularizations of the work of CRU and others often contain oversimplifications that omit serious discussion of uncertainties emphasized by the original authors. For example, CRU publications repeatedly emphasize the discrepancy between instrumental and tree-based proxy reconstructions of temperature during the late 20th century, but presentations of this work by the IPCC and others have sometimes neglected to highlight this issue. While we find this regrettable, we could find no such fault with the peer-reviewed papers we examined.

Oxburgh obviously did not respond to actual criticism, which was of the IPCC diagram. In May 2005, long before Climategate, I had reported the truncation of Briffa data in the IPCC report and asked the following questions:

The truncation is not documented in IPCC TAR. In most cases, people would ask: who at IPCC truncated this series? why did they do so? who approved the truncation? what process was involved in approving the truncation?

The Climategate emails obviously shed a very unsavory light on the decision to delete adverse data in IPCC TAR.

The Oxburgh panel considered the IPCC diagram only in passing, but its finds were all adverse to Mann. They described IPCC’s failure (in Mann’s section) to highlight the discrepancy as negligent and “regrettable”.

The Oxburgh panel was also very critical of the failure of CRU to involve professional statisticians in work that was essentially statistical:

2. We cannot help remarking that it is very surprising that research in an area that depends so heavily on statistical methods has not been carried out in close collaboration with professional statisticians.

The Oxburgh Press Conference

Mann’s pleadings specifically noted that the release of the various reports were covered in national and international media and the Oxburgh report was no exception. It held a press conference on April 14, 2010 that was attended by reporters from a wide range of international media. Oxburgh was accompanied by panelist David Hand, an eminent statistician who was then the President of the Royal Statistical Society.

A few days prior to the press conference, Oxburgh and Hand appear to have entertained some misgivings about Mann, which were mentioned to UEA’s Vice Chancellor Acton. Although Mann is a relatively central Climategate figure, Acton appeared unfamiliar with him, but “thought that [he] recognised the name”. On April 12, 2010, two days before the press conference, he sent the following email to Oxburgh cc Hand:


You mentioned concerns about Mann. I thought I recognised the name. Here’s the report we received from his University’s internal review which you may find of interest.

[VC Acton]

At the press conference, Hand severely criticized Mann’s reconstructions for “exaggeration” and it was these criticisms that were the story publicized in the international media and subsequently noted in a CEI blog article, which, in turn, was covered by National Review.

Louise Gray of the Daily Telegraph, generally highly sympathetic to green causes, reported that Hand had accused Mann of using “inappropriate” methods that had “exaggerated” the threat from climate change, an accusation emblazoned in the article’s headline:

The article continued with harsh words about Mann:

Professor David Hand said that the research – led by US scientist Michael Mann – would have shown less dramatic results if more reliable techniques had been used to analyse the data… But the reviewers found that the scientists could have used better statistical methods in analysing some of their data, although it was unlikely to have made much difference to their results.

That was not the case with some previous climate change reports, where “inappropriate methods” had exaggerated the global warming phenomenon. Prof Hand singled out a 1998 paper by Prof Mann of Pennsylvania State University, a constant target for climate change sceptics, as an example of this. He said the graph, that showed global temperature records going back 1,000 years, was exaggerated – although any reproduction using improved techniques is likely to also show a sharp rise in global warming. He agreed the graph would be more like a field hockey stick than the ice hockey blade it was originally compared to. “The particular technique they used exaggerated the size of the blade at the end of the hockey stick. Had they used an appropriate technique the size of the blade of the hockey stick would have been smaller,” he said. “The change in temperature is not as great over the 20th century compared to the past as suggested by the Mann paper.”

Mann had been interviewed for the Telegraph article and claimed that Peter Bloomfield of the NAS panel had “come to an opposite conclusion” from Hand:

“I would note that our ’98 article was reviewed by the US National Academy of Sciences, the highest scientific authority in the United States, and given a clean bill of health,” he said. “In fact, the statistician on the panel, Peter Bloomfield, a member of the Royal Statistical Society, came to the opposite conclusion of Prof Hand.”

The New Scientist’s report, also by a very green reporter, headlined that “Climategate scientists chastised over statistics”.

The New Scientist reported that the “strongest example of imperfect statistics” was said to occur in the work of Michael Mann, which had led to “exaggerated” results:

[Hand] said the strongest example he had found of imperfect statistics in the work of the CRU and collaborators elsewhere was the iconic “hockey stick” graph, produced by Michael Mann of Pennsylvania State University in University Park. The graph shows how temperatures have changed over the past 1000 years (see graphic, right). Hand pointed out that the statistical tool Mann used to integrate temperature data from a number of difference sources – including tree-ring data and actual thermometer readings – produced an “exaggerated” rise in temperatures over the 20th century, relative to pre-industrial temperatures. That point was initially made by climate sceptic and independent mathematician Stephen McIntyre.

Even the Guardian reported Hand’s broadside against Mann’s work, reporting Hand as saying that Mann’s study gave him an “uneasy feeling” because it used “inappropriate statistical tools”. Mann fought back, describing Hand as only a “rogue opinion” that “should not be given much attention or credence”, while claiming that his study had been “approved” by the US National Academy:

At a press conference to launch the review’s findings, Hand re-ignited a long-standing row about a high-profile study published in 1998 by scientists led by Michael Mann at Penn State University, US. The paper featured an emblematic graph known as the “hockey-stick” that showed temperature rise in the twentieth century was unprecedented in recent history. Hand said the study gave him an “uneasy feeling” because it used “inappropriate statistical tools”. The hockey-stick effect was genuine, Hand said, but the 1998 paper exaggerated it. He praised Steve McIntyre, a Canadian climate blogger who led much of the criticism of the CRU scientists, for identifying the problem.

Mann told the Guardian that the 1998 study had been approved by the US National Academy of Science and Hand had offered a “rogue opinion” that “should not be given much attention or credence”.

The Daily Telegraph article was covered in the US by various outlets, including Fox News, which covered the Daily Telegraph story in an article entitled Top Climate Scientist Under Fire for ‘Exaggerating’ Global Warming”, complete with large photograph of Mann.

The article contained commentary that was critical of both Mann and the Penn State inquiries, including the following:

Britain’s top statistician absolved U.K. scientists following the climate-data scandal — and blasted U.S. researcher Michael Mann for exaggerating the size of global warming.

An inquiry by a panel of scientists into the behavior and methodologies of researchers at Britain’s East Anglia University found Britain’s climatologists scatterbrained and sloppy, but ultimately innocent of intentionally skewing climate data. But one of the top scientists selected for the panel slammed the methodologies used by Penn State climatologist Michael Mann to devise his infamous “Hockey Stick.”

Mann’s Protest

Mann immediately protested to Hand in numerous emails, seeking both a withdrawal of Hand’s criticism and an apology.

On April 14, Mann emailed Hand asking to speak to him.

The next day, Mann commenced a barrage of emails by sending Hand a copy of Wahl and Ammann, noting that Nychka of NCAR was a consultant on it. (Nychka had also been a member of the NAS panel despite this conflict, a conflict that I had formally objected to.)

Mann had also sent Peter Blomfield a copy of the Telegraph article and asked him to intervene. Bloomfield wrote to Hand, but his letter did not provide the support that Mann had sought. Instead of opposing Hand’s remarks (as Mann had asserted), Bloomfield said that he had quickly reviewed the findings of the NAS report and did not locate any conclusions that differed from Hand’s:

A quick rereading of the report didn’t reveal any place where I, ^ or any other member of the committee reached any conclusion with which you would differ. If you’re aware of any, I’d be glad of a reminder!

Mann followed up his earlier email with a link to the adverse Fox News article. A few hours later, Mann talked to Hand by telephone. Mann followed up the call by sending Hand a list of talking points, including links to desmog and deepclimate attacking Wegman. Mann worried that “specious and false allegations” would “spin out of control” unless Hand issued a “clarification” that others would be able to “report and quote”. Mann wanted to know what measures Hand planned to “correct the record”:

Given all of this, as I stated in our phone conversation, I believe the only way to prevent the specious and false allegations about us and our work from spinning out of control in the media is for their to be a clarification issued on your part in the fairly near term, which others could then be able to repost and quote. Otherwise, the mischaracterizations that I know concern both of us, will continue to be propagated and promoted by those seeking to further enflame the discourse on this topic.

As you can see from the email I’ve forwarded below, my own university’s newspapers now wants to do an article about this, which puts me in a very awkward position. I don’t expect this sort of thing to stop without some action on your part, as mentioned above…

I am anxious to learn what measures you might be willing to take in the near term to correct the record, given the unusual amount of misinformation that this affair has now engendered.

Two days later (April 17), Mann again pressed Hand to withdraw his statements to avoid what Mann called the “spread of misinformation arising from the press conference”:

Please do let me know if you have any further questions I can address for you. Some sort of statement early this week (i. e, monday) would be extremely helpful in preventing the spread of misinformation arising from the press conference, which unfortunately does continue in the U. S. media, thanks in advance for any help you can provide.

Hand notified Oxburgh that he wanted to get Mann off his back (“since Mann is continuing to pursue me”). Hand drafted an anodyne addendum to the report, saying that they had not “intended to imply” that other groups had been “deliberately misleading” or “intentionally exaggerated” their finds, but only to emphasize the “complexity of statistics” and the “need to use the best possible methods”.

For the avoidance of misunderstanding in the light of various press stories, it is important to be clear that the neither the panel report nor the press briefing intended to imply that any research group in the field of climate change had been deliberately misleading in any of their analyses or intentionally exaggerated their findings. Rather, the aim was to draw attention to the complexity of statistics in this field, and the need to use the best possible methods.

Hand, Oxburgh and the UEA agreed that they would add the new paragraph “quietly”, commenting:

I could be wrong, but can’t see it getting much interest without people being directed to it.

The addendum was posted up on April 19 without any fanfare or announcement. Mann appears to have anticipated much more. On April 23, Tom Heap of the BBC wrote to Fiona Fox of the Science Media Center saying that Mann had claimed that Hand’s criticism was “all wrong” and that Hand would be “issuing a clarification/apology”:

By the way, Mann said Hand got his criticism of the stats all wrong and would be issuing a clarification/ apology. True?

Fox passed the inquiry to Hand, asking if Hand planned to issue an apology ( “assuming (praying) that it is not true”), observing that, if not, then someone should suggest to Mann that he not make such suggestions to BBC reporters:

Subject: aghhhhhhhhhhhhhhhhhh

Hi Folks – assuming (praying) this is not true? If it – or any version of it – is true – can we chat about it and how the SMC might help? If it’s rubbish someone might want to suggest to Michael Mann that he decease from suggesting it to BBC reporters.

In the event, Fox’s prayer was answered as neither Hand nor the Oxburgh panel issued any further “clarification/apology”.

CEI and National Review

In July 2010, CEI’s Iain Murray published an article in the Wahington Examiner (later republished at the CEI website here) that severely criticized defects in the UK Parliamentary Committee, Oxburgh, Muir Russell and Penn State inquiries, concluding:

Those who hope that these inquiries exonerate global warming science are engaging in wishful thinking. The Climategate e-mails are still there for all to read and the questions they raise remain unanswered. Until there are answers, Climategate rolls on.

While Murray was critical of the shortcomings of the Oxburgh panel, including its failure to “examine the quality of the science at all”, he observed that it “suggested deeper problems”, including Hand’s assertion that Mann had used “inappropriate statistical methods” (citing the Guardian) while noting that Mann dismissed Hand as merely a “rogue opinion”:

The parliamentary inquiry was also assured by the UEA that the quality of the science would be reviewed by another inquiry to be headed by Lord Oxburgh. Yet Lord Oxburgh’s panel handed down a short report which did not examine the quality of the science at all.

The panel simply reviewed a selection of CRU papers — selected by the UEA itself — and pronounced itself satisfied that the scientific process was fair and proper. The chairman of the parliamentary committee, Labor legislator Phil Willis, told the BBC he “could not believe” this “sleight of hand.”

Yet this cursory review suggested deeper problems. In his review of the hockey stick itself, according to the Guardian newspaper, the panel’s statistician David Hand said that the scientists had used inappropriate statistical methods. Hockey stick co-author Michael Mann of Penn State University dismissed this as a “rogue opinion.”

Murray’s article was quoted at length in a National Review Online opinion article on July 20, 2010 here.

Murray had observed that the Muir Russell investigation (which I’ll examine separately) had not interviewed any critics, but still concluded that Mann’s graphic in IPCC TAR was “misleading”. Murray commented:

Even this inadequate investigation, however, found that the way the hockey stick graph was handled was misleading. Imagine what it — and the parliamentary committee — would have found if there had been some witnesses for the prosecution.

To which, National Review Online added sarcastically:

Witnesses? Who needs witnesses?


As noted at the start, Mann’s pleadings assert that he was “investigated” by multiple investigations and that all of the investigations (i.e. including Oxburgh) exonerated him of scientific misconduct, fraud, academic fraud, data falsification, statistical manipulation, manipulation of data and even supposed findings that his work was “properly conducted and fairly presented” and that these findings were announced and reported in “international and national media” of which the defendants were aware.

However, it is evident that the Oxburgh panel did not interview Mann or carry out any of the steps necessary to conduct an investigation of Mann’s work and that they did not provide the wide-ranging “exoneration” asserted in Mann’s pleadings. Furthermore, public statements by members of the Oxburgh panel on Mann’s work were highly critical and, far from indicating the widespread exoneration claimed by Mann, suggested the opposite. Indeed, Mann himself at the time perceived these opinions as damaging to himself, as he dismissed Hand’s as a “rogue opinion” and unsuccessfully sought an apology from Hand.

Postscript: In October 2013, at the request of Steptoe, the then lawyers for National Review and Steyn, I visited them in Washington to provide background on the dispute. Steptoe paid my travel expenses, but I was not offered (nor did I request) remuneration for my time. During the trip, I also provided a briefing with CEI’s counsel. Following my trip, Steptoe proposed that I act as a consultant to National Review in the litigation, but I didn’t follow up or enter into any agreement. I am reluctant to enter into a consulting agreement at present, since I want to preserve my ability to comment independently. On the other hand, I can envisage circumstances in which I might enter into a consulting agreement with one of the parties and perhaps even be remunerated for my time: everyone else seems to get paid. If that happens, I’ll disclose it.

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