Michael Mann responds to the “false and misleading claims” in the error-riddled, defamatory WSJ piece by Jeffrey Ball and Keith Johnson
Has the WSJ's vaunted 'firewall' between straight news and ideological-driven editorials been breached?
by Joseph Romm, Climate Progress, February 26, 2010I’d like your help debunking this atrocious piece of media misreporting, “Push to Oversimplify at Climate Panel.”
Yes, the WSJ piece wins the prize for the most unintentionally ironic headline since it is the media’s self-destructive push to oversimplify that has led to repeated libeling of Michael Mann and other climate scientists (see “Newsweek staff who play fast and loose with the facts are imperiling not just their profession but the planet” and “Abandoning all journalistic standards, CBS libels Michael Mann based on a YouTube video — while reporting his exoneration!”
I am running a full response by Dr. Mann below. It seems the least I can do in response to the umpteenth false attack on his reputation. It simply boggles the mind — and raises serious questions of journalistic bias for the paper — that the WSJ can run this error-riddled attack on Mann and the Hockey Stick without even mentioning any of these three central facts:
- The Hockey Stick was affirmed in a major review by the uber-prestigious National Academy of Scientists (in media-speak, the highest scientific “court” in the land).
- The Hockey Stick has been replicated and strengthened by numerous independent studies. My favorite is from Science last year — see Human-caused Arctic warming overtakes 2,000 years of natural cooling, “seminal” study finds (the source of the figure below).
- Penn State itself in recent review, concluded, “After careful consideration of all the evidence and relevant materials, the inquiry committee finding is that there exists no credible evidence that Dr. Mann had or has ever engaged in, or participated in, directly or indirectly, any actions with an intent to suppress or to falsify data.”
In other words, maybe it should:
Here is Mann’s quick response to the piece:
The article creates a factually incorrect narrative by conflating a number of unrelated things which follow a timeline that doesn’t support the interpretation provided. It refers to email discussions between Keith Briffa and various 2001 IPCC report chapter 2 on “climate observations” co-authors, including Chris Folland, myself, and others:
“I know there is pressure to present a nice tidy story as regards ‘apparent unprecedented warming in a thousand years or more,’ ” he wrote to other researchers in the email, among those hacked at East Anglia. “In reality the situation is not quite so simple,” Mr. Briffa wrote.
These emails were from 1999 and referred to an early draft of the IPCC report. In this draft, Briffa had provided a reconstruction of past temperatures based on high-latitude tree-ring density data. Briffa had used an extremely liberal means for removing “growth trends” which left very little long-term variability in the reconstruction at all. Convening lead author Chris Folland had indicated that Briffa’s reconstruction detracted from the comparison with other reconstructions that were shown (one of ours, and one co-authored by Phil Jones, as well as Briffa himself, and others) which were based on multiple types of proxy records (ice cores, corals, tree-rings, sediments, historical documents). Both of these latter two reconstruction showed far more low-frequency variability and better consistency with instrumental temperature data.
Subsequent to that discussion, Briffa and colleagues went back and used more conservative methods to produce a tree-ring density-based temperature reconstruction with more faithful retention of long-term variability. This reconstruction was shown with the two other (Mann et al. and Jones et al.) reconstructions in the final draft of the IPCC report. All three reconstructions indicated that the recent warmth was anomalous in the long-term context of the reconstruction (back 1000 years for Jones et al. and Mann et al., while Briffa et al. only went back 600 years).
Even the revised Briffa et al. reconstruction suffered from yet another problem however. This problem was well known, as was the focus of Briffa et al.’s original 1998 article [Briffa, K. R., F. H. Schweingruber, P. D. Jones, T. J. Osborn, S. G. Shiyatov, and E. A. Vaganov (1998), Reduced sensitivity of recent tree-growth to temperature at high northern latitudes, Nature, 391, 678–682] presenting their high-latitude tree-ring density dataset. What they noted in their original article is something peculiar to these tree-ring data (it does not generally apply to other tree-ring data, let alone other proxies such as ice cores, corals, etc), that they stop accurately reflecting temperatures after about 1960. For this reason, the reconstruction is typically (as was the case in the IPCC report) terminated at 1960 when the tree-ring data are known to be unreliable. The reason for this so-called “divergence problem” is still an area of active research by dendroclimatologists–it may be due to other limiting influences on tree-growth in recent decades such as pollution. In any case, however (i) the problem was well recognized in the IPCC report and was discussed clearly in that report [see: http://www1.ipcc.ch/ipccreports/tar/wg1/068.htm ], only applied to one of the three reconstructions shown in the IPCC report (the Briffa et al. tree-ring density data), and not to the multiple-proxy based reconstructions of Mann et al. (the “Hockey Stick”) and of Jones et al. (1998).
Given the above information (which Johnson was provided before this article was published) it is clear that the following statement by Ball and Johnson is completely false:
The problem: Using Mr. Briffa’s tree-ring techniques, researchers in the ’90s built charts suggesting temperatures in the late 20th century were the highest in a millennium. The charts were dubbed “hockey sticks” because they showed temperatures relatively flat for centuries, then angling higher recently.
There is not even a grain of truth to the statement. Neither the multiple proxy-based “Hockey Stick” reconstruction of Mann et al nor the multiple-proxy based Jones et al. reconstruction used “Mr. Briffa’s tree-ring techniques” let alone their data.
Ball and Johnson compound the erroneous statements by:
But Mr. Briffa fretted about a potential issue. Thermometers show temperatures have risen since the ’60s, but tree-ring data don’t move in tandem, and sometimes show the opposite. (Average annual temperatures reached the highest on record in 2005, according to U.S. government data. They fell the next three years, and rose in 2009. All those years remain among the warmest on record.)
The statement falsely implies that the Hockey Stick reconstruction of Mann et al. central to their discussion somehow suffers from the problems of the Briffa et al. reconstruction. It simply doesn’t. The statement is false, and indeed it is only this false assertion which allows the authors to try to fit the Hockey Stick into their disingenuous overall narrative about the IPCC supposedly exaggerating science.
The problem is further compounded by a similarly disingenuous statement later on in the article:
The data were the subject of heated back-and-forth before the IPCC’s 2001 report. John Christy, one of the section’s lead authors, said at the time that he tried in vain to make sure the report reflected the uncertainty.
Mr. Christy said in an interview that some of the pressure to downplay the uncertainty came from Michael Mann, a fellow lead author of that chapter, a scientist at Pennsylvania State University, and a developer of the original hockey-stick chart.
The “very prominent” use of the hockey-stick chart “overrules what tentativeness some of us actually intended,” Mr. Christy wrote to the National Research Council in the U.S. a month after the report was published. Mr. Christy, a climate scientist at the University of Alabama in Huntsville, provided that email.
If John Christy made the above statements, then he too has been untruthful. In fact, the use of the term “likely” (which was agreed upon by all IPCC chapter 2 co-authors including Mr. Christy) in assessing whether recent warmth is unusual in a millennial context, is precisely the same wording that was used by Mann et al. themselves in their original millennial Hockey Stick article which has the words “limitations” and “uncertainties” in the very title of the paper: Mann, M.E., Bradley, R.S. and Hughes, M.K., “Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations,” Geophysical Research Letters, 26, 759-762, 1999. During a press conference following the 2006 release of a National Academy of Sciences report widely viewed as a vindication of the Mann et al. work (BBC: “Backing for the Hockey Stick”; New York Times: “Science panel backs study on warming climate”; Nature: “Academy Affirms Hockey Stick Graph”) the chairman of the NAS committee, Gerald North of Texas A & M, asked about whether Mann et al. had ever over-stated their conclusions, attributed any blame for overstatement of the conclusions to others: “The community probably took the results to be more definitive than Mann and colleagues intended.”
The “tentativeness” of the conclusions was emphasized in the original 1999 article. The question that was actually debated by the IPCC chapter 2 co-authors was how to make an assessment of confidence given that one of the three studies (Mann et al.) had estimated uncertainties in reconstructed values, making it possible to obtain a statistical estimate of significance, and allowing the conclusion to be drawn that recent warmth was “likely” anomalous in at least the past 1000 years. However, the two others (Jones et al. and Briffa et al.) did not estimate the uncertainties in the reconstructed values, making it difficult to draw statistical inferences. The IPCC chapter 2 lead authors collectively determined that “likely” (amounting to a roughly 2/3 likelihood), the same choice used by Mann et al. themselves, was the best level of confidence to attribute to the collective evidence from the three reconstructions.
Perhaps most troubling is this sentence:
“I was suspicious of the hockey stick,” Mr. Christy said in an interview. Had Mr. Briffa’s concerns been more widely known, “The story coming out of the [report] may have been different in tone and confidence.”
If Christy did indeed say this, then he knowingly made a false claim in the Wall Street Journal. As a participant in the IPCC chapter 2 deliberations, he surely was aware that the “concerns” by Briffa et al. referred to an early comparison in a draft report, objected to by convening lead author Chris Folland due to the known problems with the early version of the Briffa et al. reconstruction in that version of the plot. The final plot that appeared containing Briffa’s most up-to-date reconstruction. That plot suffered from the “divergence” problem, but the Hockey Stick did not. By implication, the reader is again led to believe that this “problem” somehow compromises the reliability of the Hockey Stick when it in fact has absolutely no relevant to the Mann et al. Hockey Stick reconstruction at all – it only applies to the Briffa et al. reconstruction shown in the IPCC report.
What is even more troubling is the asymmetry of the criticism by Ball and Johnson.
A far more interesting set of questions would have involved John Christy and his satellite estimates which were used by contrarians in the climate debate for more than a decade to cast doubt on the reality of global warming. Christy was indeed pushing personally for the conclusion that there is little warming evident over the past few decades, purely based on his own satellite estimates with Roy Spencer which contradicted all other lines of evidence supporting warming. A few years ago, independent teams of scientists got ahold of their satellite data and after repeated questioning of them about their methods found that there were two critical errors in their algorithm. One of them was a sign error in the diurnal correction term, the other was an algebraic error. Once those errors were corrected by other scientists, the Christy and Spencer claim that satellite data contradict surface evidence of warming evaporated.
There is a good summary of these developments by William Connelly here:
http://www.realclimate.org/ index.php/ archives/ 2005/ 11/ more-satellite-stuff/
By contrast with the key conclusion of Christy and Spencer’s original work (that the atmosphere was not warming), which has now been overturned by all independent assessments, the Mann et al. work has stood up remarkably well. the most recent IPCC report not only affirming the Mann et al. conclusions, but extending them further back based on the existence of more than a dozen reconstructions that now point to the same question: The 2007 IPCC report found that recent warming is *likely* unprecedented for at least the past *1300* years.
Why wasn’t the WSJ more interested in the Christy & Spencer story? Why didn’t they interview Frank Wentz of the RSS group in California, who discovered the Christy and Spencer error? Not only was it an honest-go-goodness error, it mattered – it provided a specious talking point (”the atmosphere isn’t warming”) for climate change deniers for more than a decade. And it was a product of some botched algebra by Christy and Spencer. There was no scientific validity to the claim at all.
The authors of the WSJ story were provided all of the information indicated above. They still chose to publish false and misleading claims. Unfortunately, this has become par for the course for the Wall Street Journal, whose denialist opinion page rhetoric is increasingly creeping past the supposed “firewall” into their news division.[Joe Romm, again, below.]
The WSJ owes Mann an apology and a major retraction.
Failure to do so will feed the suspicion that their rabidly anti-science editorial page is infecting — directly or indirectly — their news coverage.
And yes, quoting Christy as a reliable source on the matter without mentioning his catastrophic and consequential decade-long series of miscalculation is indicative of the “asymmetric” standard the disinformers are held to, as Energy Secretary Steven Chu put it, “ What standard are they being held to? It’s very asymmetric. They get to say anything they want.” See also “Should you believe anything John Christy and Roy Spencer say?”
There are many, many more erroneous and misleading statements in the WSJ piece — aside from the fact that the entire thrust of the piece is disingenuous: The media bears a great deal of the culpability for any oversimplification in the presentation of the IPCC’s results, a point Dr. Alley alludes to.
But here’s where you come in. I’ve already spent the entire morning on this and am out most of the afternoon. So I’d like you to document the other errors and distortions in the piece, and over the weekend I will highlight the best of what your write, which is to say, the worst of what the WSJ wrote.
Link: http://climateprogress.org/2010/02/26/michael-mann-false-and-misleading-claims-wall-street-journal-oversimplify-piece-by-jeffrey-ball-and-keith-johnson/#more-20042
No comments:
Post a Comment