Michael Mann

Book Review: The Hockey Stick and the Climate Wars

The following is my review of The Hockey Stick and the Climate Wars, by Michael Mann - I read the Kindle edition (and sent him a few corrections for typos here and there).

As I was reading this first-person account of some of the most maddening episodes in modern times, I wondered to myself - what audience is this written for? How will some of the different players and bystanders react? Is Dr. Mann bringing on himself here yet another round of baseless attack from those who side with the most powerful entities human civilization has ever known?

I have no doubt the attacks will continue to intensify. If you hear about this book from some of the people, foundations and corporations that Mann names in it, please remember they have a very strong agenda: they don't want you to read it. If you find yourself sympathizing with one of these powerful entities, that means you need to read it, more than anybody else.

Deep Problems with the Wegman Report

On May 6th, 2010, climate skeptic Christopher Monckton testified before the US House Select Committee on Energy Independence and Global Warming. The hearing was supposed to be on The Foundations of Climate Science. Democrats on the committee invited 4 leading scientists from major US scientific institutions to testify; Monckton was the only witness on the Republican side. Commitee membership is listed online and includes James Sensenbrenner of Wisconsin as the ranking member on the Republican side, who presumably was responsible for selecting Monckton. It's hard to believe the Republicans were even taking the hearing seriously with that choice. Nevertheless, many climate scientists and other observers were quite disturbed by the misinformation provided as testimony by Monckton to the hearing. A comprehensive rebuttal of Monckton's claims was recently put together by leading climate scientists, with sample comments from them including "very misleading", "profoundly wrong", "simply false", "chemical nonsense", and "cannot be supported by climate physics".

HockeyStick.png Unfortunately, this is far from the first time congressional Republicans have perpetrated this sort of stunt. An example with far worse implications is the story of the "Wegman Report", supposedly an analysis of the science underlying scientist Michael Mann's early work on reconstruction of historical temperatures, the so-called "hockey stick" (to the right), which showed that temperatures now are warmer than they have been for many centuries, and getting hotter very fast. Mann's results have been repeatedly reproduced with differing methods by himself and other researchers. A 2006 review by the prestigious National Academy of Sciences determined that, according to data and methods available at that time:

  • It can be said with a high level of confidence that global mean surface temperature was higher during the last few decades of the 20th century than during any comparable period during the preceding four centuries. This statement is justified by the consistency of the evidence from a wide variety of geographically diverse proxies.
  • Less confidence can be placed in large-scale surface temperature reconstructions for the period from A.D. 900 to 1600. Presently available proxy evidence indicates that temperatures at many, but not all, individual locations were higher during the past 25 years than during any period of comparable length since A.D. 900. The uncertainties associated with reconstructing hemispheric mean or global mean temperatures from these data increase substantially backward in time through this period and are not yet fully quantified.
  • Very little confidence can be assigned to statements concerning the hemispheric mean or global mean surface temperature prior to about A.D. 900 because of sparse data coverage and because the uncertainties associated with proxy data and the methods used to analyze and combine them are larger than during more recent time periods.

This NAS report, chaired by Gerald North of Texas A&M University, was actually requested by a congressional Republican - Sherwood Boehlert of NY, who was at the time chair of the House Science Committee. He has since retired - one of the last sensible Republicans in congress.

But other congressional Republicans were not interested in what field scientists had to say, and came up with an alternative report on the "hockey stick". Representatives Joe Barton and Ed Whitfield requested a separate report from statistician Edward Wegman, and had Wegman and colleagues testify to congress about the results. The Wegman report seemed to raise a lot of questions about the "hockey stick" and climate science in general. People who have examined the report in isolation may have been quite impressed by some of its claims - just as those lacking expertise might be impressed by Monckton's song and dance. Now, 4 years after its release, computer scientist John Mashey has done an in-depth study of the report and found a large number of indicators of shockingly low academic quality, and further indications that the report was actually tailored as part of a public relations campaign orchestrated by the usual anti-global-warming suspects (conservative and libertarian think tanks, sponsored by fossil fuel concerns).

Michael Mann's errors

[UPDATE July 1, 2010: Penn State just today issued a final report on their investigation into allegations of misconduct by Dr. Mann. Note their criteria for misconduct were as follows:

(1) fabrication, falsification, plagiarism or other practices that seriously deviate from accepted practices within the academic community for proposing, conducting, or reporting research or other scholarly activities;
(2) callous disregard for requirements that ensure the protection of researchers, human participants, or the public; or for ensuring the welfare of laboratory animals;
(3) failure to disclose significant financial and business interest as defined by Penn State Policy RA20, Individual Conflict of Interest;
(4) failure to comply with other applicable legal requirements governing research or other scholarly activities.
where "research misconduct does not include disputes regarding honest error or honest differences in interpretations or judgments of data, and is not intended to resolve bona fide scientific disagreement or debate."

The report concludes "there is no substance to the allegation against Dr. Michael E. Mann"; the worst they could say was that he was somewhat "careless" in sharing unpublished manuscripts with colleagues. However, this was a pretty high-level review, and seems it did not get into the "Tiljander" issue. So we'll see where that goes here.]

Deep Climate has a new post up concerning the IPCC TAR Figure 2.21 "hockey stick" curves prepared by lead author Michael Mann for the 2001 report. This follows up on my post looking into similar questions regarding the AR4 Figure 6.10b "hockey sticks" in the latest (2007) report. Despite Steven Mosher's claims that the same rather subtle "trick" of padding the Briffa curve with instrumental temperatures was used in both figures, my analysis showed it could not have been in the AR4 case. Deep Climate has now shown that it's possible this padding was used for the Briffa curve in the TAR figure, but it makes essentially no difference (0.01 degrees over about 10 years, almost imperceptible in the full graph). The Mann curve in the TAR figure ("MBH") clearly was padded from 1980 with instrumental temperatures in the end-point smoothing, while the Jones curve in that figure clearly was not. The details of Mosher's (and McIntyre's, in this case) accusations about Mann and Briffa also seem to be contradicted by the actual record as DeepClimate shows, but that's another matter.

In any case, there definitely was an issue with the way Michael Mann was doing end-point smoothing in several of his early published papers, and in at least one of the curves in this IPCC report. As noted in the previous discussion, Mann admitted to this several years ago and indicated it wouldn't happen again, and it doesn't seem to have. So, an error, with minor impact on a couple of curves, since repented of.

In my last post, I called for the best examples of anything close to fraud by climate scientists, in particular Mann. There certainly are a number of cases where he has made similar errors that seem to have not substantially effected the results, but still were indicative of a certain carelessness, and sometimes stubbornness in recognizing the problem. And there are other examples of minor errors by other groups, for example several glitches in the GISS instrumental temperature analysis over the years that caused minor shifts in historical temperature numbers, particularly regionally.

Of course the worst case of unacknowledged errors in climate science was probably the UAH satellite analysis, which for 26 years was substantially under-reporting warming due to an algebra error in the analysis.

People make mistakes; as long as they correct them when the error is detected, it's really not such a big deal. The question I raised in my "Where's the fraud?" post was whether there was any substantive error of some sort that had not been admitted or corrected after exposure.

Where's the fraud?

In previous posts I have discouraged discussion of Michael Mann's work since I had not investigated it at all myself - but inevitably it came up anyway. There were a couple of interesting comments from Steve Mosher and AMac that I am highlighting in this post. If commenters here agree that the Tiljander case is the closest thing anybody has come up with to show consistent misbehavior by climate scientists (following the basic "fraud-like" criteria I set out) then I commit to looking into it myself and trying to understand why scientists and bloggers seem to be disagreeing about it. AMac's denial of "fraud" while calling it an "honest mistake" seems odd to me - if it's really an "honest mistake" it should be acknowledged, not repeated.

Or if folks here think the Tiljander case is not a real problem but some other hockey stick "trick" or feature is definitely fraudulent, I'll look there. Tell me what your best case is!

Just because scientists are human - that is biased, inconsistent, lazy, argumentative, make mistakes, argue, play "politics", etc. etc. does not make some piece of science a fraud. Scientists in their natural state are fiercely competitive with one another - recognition for solving some problem or being first to discover some new truth about the world is all that matters. Tearing down somebody else's work, if you're right, is always grounds for praise. As long as there is some collection of predictions about the world from a piece of science and measurements to verify those predictions, then no matter what the biases or mistakes of the scientists involved, as long as they are not being deliberately fraudulent, the truth will prevail. Of course, without that check and balance from nature, even without fraud, science can get wildly speculative (*cough* string theory *cough*).

Human frailties can mar any piece of scientific work, and this shouldn't surprise anybody. The worry is that some pieces of work that people have come to respect and rely on have been, in some manner, fabricated and are themselves wrong. But fraud is hard to perpetuate in science - it almost always turns up later when others try to do the same experiment or analysis over again and consistently get some different result. On the other hand, if there has not been any actual fraud, what's the problem? The science is still right, even if the scientists behaved abominably (and I've personally witnessed some pretty abominable stuff from people who received great honors...). That's sort of the beauty of the objectivity that the intrinsic competition and reference to nature of science forces on you: personalities really don't matter, only the truth does - it's only the thought that counts as I wrote some time ago.

But - there have been cries of fraud. Let's try to get to the bottom of them. Here are 5 objective criteria for clear continuing fraud that I posted here in a comment the other day:

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