Wegman (and Rapp) on tree rings: A divergence problem (part 1)


Edward Wegman


There has been renewed interest in the Wegman Report, which purported to critique the work of paleoclimatolgists Michael Mann, Raymond Bradley and Malcolm Hughes and their controversial “hockey stick” millennial temperature reconstruction.

Today we’ll take a closer look at Wegman et al’s key passage on tree-ring proxies and do a detailed side-by-side comparison with its apparent main antecedent, chapter section 10.2 in Raymond Bradley’s classic Paleoclimatology: Reconstructing Climates of the Quaternary.

That comparison leaves no doubt that Wegman et al’s explication was substantially derived from that of Bradley, although the relevant attribution appears to be missing. There are, however, several divergences of note, also in the main unattributed, and some of Wegman’s paraphrasing introduces  errors of analysis.

But the real shocker comes in two key passages in Wegman et al, which state unsubstantiated findings in flagrant contradiction with those of Bradley, apparently in order to denigrate  the value of tree-ring derived temperature reconstructions.

My first post on the Wegman Report showed that all of Wegman’s proxy explication had been incorporated almost verbatim into Donald Rapp’s text book Assessing Climate Change.

But I also noted that the opening passage of Wegman’s tree ring explication, starting at p. 13,  was mainly derived from Bradley. So I decided a detailed analysis of the entire section might be revealing. (For purposes of this discussion, Wegman and Rapp are essentially identical; interesting “divergences” between Wegman and Rapp will be discussed in part 2.)

To perform the analysis, I downloaded the two documents (linked at the end of this article), found all the relevant passages in Bradley,  and placed the two  passages side-by-side in a single PDF document. The text has been reformatted into sub-paragraphs for ease of direct comparison; each page of the comparison corresponds to one paragraph from Wegman et al (three in all). The text has been formatted as follows:

  • Regular font for sentences with substantial wording in common between Wegman and Bradley
  • Italic for Bradley material paraphrased in Wegman
  • Bold for significant departures in Wegman with respect to Bradley
  • Bold italic to indicate passages where Wegman and Bradley contradict each other

With that material in hand, let’s begin.

As noted in my previous post, Wegman’s first paragraph is very close to Bradley, with near-identical wording dominating, along with some close paraphrasing. One of the paraphrased sections introduces an error of perhaps some consequence.

Bradley states:

However, optimum climatic reconstructions may be achieved by using both ring widths and densitometric data to maximize the climatic signal in each sample (Briffa et al., 1995).

Wegman’s version implies the practice of combining indices is the norm rather than specific to particular situations:

Both tree ring width and density data are used in combination to extract the maximal climatic temperature signal. [Emphasis added]

Also as noted in my previous post, one departure is the addition of carbon dioxide at the end of the list of “climatic factors”, which seems misplaced. Another, immediately following,  is the insistence (and repetition) of the role of “confounding factors”:

Obviously there are many confounding factors so the problem is to extract the temperature signal and to distinguish the temperature signal from the noise caused by the many confounding factors. [Emphasis added]

Bradley’s original uses a more conventional signal-noise formulation:

The problem facing dendroclimatologists is to extract whatever climatic signal is available in the tree ring data and to distinguish this signal from the background noise.

Wegman’s second paragraph, covering Bradley’s discussion of site and sample selection, contains more paraphrasing and less of the same direct wording. There is, however, one pair of sentences that are very close, but with a crucial difference. Bradley has:

Trees growing near to the latitudinal or altitudinal treeline are mainly under growth limitations imposed by temperature and hence ring-width variations in such trees contain a strong temperature signal.

Now here’s Wegman, with a small, but significant change:

Trees growing near to their ecological limits either in terms of latitude or altitude show growth limitations imposed by temperature and thus ring width variations in such trees contain a relatively strong temperature signal. [Emphasis added]

Is any comment necessary?

Wegman concludes the paragraph with a passage about the effects of carbon dioxide and nitrous oxide on tree rings. The first is attributed to Graybill and Idso (1993), while the second is unattributed. The relevance is unclear, to say the least, since the discussion concerns varying climatic conditions at that affect tree ring growth at different sampling sites. It may be that this topic is introduced in order to cast doubt on the value of tree ring reconstruction.

The final paragraph discusses standardization, as well as touching on calibration. Wegman starts out:

Wider rings are frequently produced during the early life of a tree. Thus the tree rings frequently contain a low frequency signal that is unrelated to climate or, at least, confounded with climatic effects such as temperature. In order to use tree rings as a temperature signal successfully, this low frequency component must be removed.

This is not completely wrong, although the odd usage of a “signal” that is “confounded” with climatic effects seems backward, and the description does not clearly state that we are speaking here of an individual tree core sample.  Bradley is much clearer, referring to the removal of “the growth function peculiar” to a “particular tree”.

Perhaps this confusion explains the very next sentence in Wegman (emphasis added in this and following quotes):

Because the early history of tree rings confounds climatic signal with low frequency specimen specific signal, tree rings are not usually effective for accurately determining low frequency, longer-term effects.

Nowhere does Wegman refer to Bradley’s explanation of “regional curve” standardization, whereby a “regional curve” is derived in order to preserve low frequency climatic information, in contradiction of the assertion above.

… The resulting “regional curve” provided a target for deriving a mean growth function, which could be applied to all of the individual core segments regardless of length (Fig. 10.13). Averaging together the core segments, standardized in this way by the regional curve, produced the record shown in Fig. 10.12b. This has far more low frequency information than the record produced from individually standardized cores (Fig. 10.12~) and retains many of the characteristics seen in the original data (Fig. 10.12a).

Wegman’s final passage discusses calibration of the proxy to the instrumental record, before pointing to Bradley (finally) for further information. Just before that, though, we have this extraordinary, unattributed (and unsubstantiated) statement:

As pointed out earlier, many different sets of climatic conditions can and do yield similar tree ring profiles. Thus tree ring proxy data alone is not sufficient to determine past climate variables.

It’s hard to know what to make of that statement. The most charitable explanation is that it is the trivial observation that a tree ring proxy must be calibrated to the temperature record over some portion of the chronology to provide a useful reconstruction. But this calibration would still be required even if tree rings only responded to temperature and not to other “climatic conditions” (which apparently even include CO2 and NO2).

So, in context, Wegman appears to imply that  tree ring proxy data must be supplemented by other proxies.

Bradley, as one might expect, draws the completely opposite conclusion.

If an equation can be developed that accurately describes instrumentally observed climatic variability in terms of tree growth over the same interval, then paleoclimatic reconstructions can be made using only the tree-ring data.

What’s next a finding that black is, after all, white? One can only be thankful that a discussion of the albedo effect was beyond Wegman’s scope.

[Update, Dec. 24: Lest readers imagine that problems in the background section on proxies have no impact on Wegman’s findings, here is one key finding (number 7 on p. 49):

7. Our committee believes that the assessments that the decade of the 1990s was the hottest decade in a millennium and that 1998 was the hottest year in a millennium cannot be supported by the MBH98/99 analysis. As mentioned earlier in our background section, tree ring proxies are typically calibrated to remove low frequency variations. The cycle of Medieval Warm Period and Little Ice Age that was widely recognized in 1990 has disappeared from the MBH98/99 analyses, thus making possible the hottest decade/hottest year claim. However, the methodology of MBH98/99 suppresses this low frequency information. The paucity of data in the more remote past makes the hottest-in-a-millennium claims essentially unverifiable. [Emphasis added]

This finding apparently rests at least in part on the fundamental misunderstanding, or at best an oversimplification, of tree-ring proxy standardization methodology (as well as an apparent confusion concerning previous knowledge about the MWP).]

Clearly, the problems I have exposed here go well beyond lack of proper attribution.  Wegman et al have followed closely Bradley’s exposition, but have still managed to introduce mistakes and even gross distortions.

That such a shoddy misrepresentation of another author’s work has been used as part of a baseless, politically motivated attack on that author is beyond shameful. Perhaps it is time to interrupt the incessant braying about so-called Climategate, and examine a real outrage for once.  “Sound science” indeed!


[Correction and reversion, Dec. 24: The accidentally missing word “signal” has been restored in the first quote from Wegman. Commentary has reverted to the original post, as Arthur Smith’s criticism was based on a misunderstanding engendered by the missing word. Thanks to Michael Smith for pointing out the error.]



Ad Hoc Committee Report on the ‘Hockey Stick’ Global Climate Reconstruction, Edward J. Wegman, David W. Scott and Yasmin H. Said. [PDF]

Paleoclimatology: Reconstructing Climates of the Quaternary (Second Edition), Raymond S. Bradley (Academic Press, 1999) [Link]  [Chapter 10: Google cache]

Wegman-Bradley Tree Ring Comparison [PDF]


70 responses to “Wegman (and Rapp) on tree rings: A divergence problem (part 1)

  1. Oh my, so when somebody writes something that you don’t like or is potentially harming your or your friend’s interests, this is what you have to do: You take that person’s work, rephrase what he says and intersperse the rephrasing with words that tone down and confound.

    It reminds me a bit of the way White House appointees (former employees of fossil fuel multinationals) edited scientific reports.

    And it works!

    Amazing… 😦

  2. Wonder who helped Wegman with the gross distortions and convenient editing of text to change the message? Wegman could not have done so alone because he did not have the necessary background, so someone had to have helped him who had knowledge about dendro chronologies and their limitations. Could it have been an infamous Canadian duo who helped him muddy the waters?

  3. Rattus Norvegicus

    The NOx stuff comes from Fenn, et. al. Bioscience, 2003. The only problem is that there isn’t a whole lot of evidence to back up the claims from the wild. In particular Salzer, et. al. PNAS, 2009 pretty well destroyed Graybill and Idso’s CO2 fertilization hypothesis.

  4. hasn t there been an audit of this?

    thanks for all this work DC, very good analysis!

  5. This really boggles the mind. Am I getting this right? Wegman copies text – unattributed text – from Bradley, massaging the meaning to get the meaning he wants, in order to discredit … Bradley?

    *head spins*

  6. Yanno, on every “skeptic” blog I read, I see Wegman held up as *the* authoritative source proving that MBH and the hockey stick are both dead. It is held up as evidence that the papers are wrong and the science questionable, and the scientists incestuous.

    What I see seems an awful lot like outright plagiarism and distortion. Given the provenance of the report, I have other doubts about objectivity as well.

  7. I presume this rather egregious example of outright plagiarism will be brought to the attention of Wegman’s University as well as the appropriate professional society.
    I would consider it an important potential disciplinary matter.

  8. Daniel J. Andrews

    I think I’m missing something when Wegman says

    …and thus ring width variations in such trees contain a relatively strong temperature signal.

    vs Bradley’s

    hence ring-width variations in such trees contain a strong temperature signal.


    Why is Wegman’s “relatively” addition wrong? Is it because it seems to weaken the strength of Bradley’s statement? At the moment I don’t see this section as damning even when I read the pdf versions. It makes me think I’m missing something obvious.

    [DC: Yes, it is a gratuitous weakening of the statement. They just can’t help themselves.]

  9. DC, you missed the worst part of your first comparison – a part that indicates whoever wrote this (Wegman or other) didn’t actually understand:

    “maximize the climatic signal” was Bradley’s, vs.
    “extract the maximal climatic temperature” in Wegman’s.

    Maximizing a (mainly temperature) signal is very different from maximizing a temperature – when the signal goes negative then you’re looking for the combination with the lowest value, when positive looking for the highest – by maximizing the signal you’re maximizing the *match* to real temperatures, not the temperature itself.

    [DC: You’re right – I need go through with an even finer tooth comb on this. It seems they can’t change a single thing without introducing an error.

    There are other errors as well (for instance another Wegman paraphrase conflates “preconditioning” growth with serial correlation, which are actually two different effects), but at a certain point I had to stop.]

  10. Was Philip Cooney still in White House at that time? This looks like his handiwork.

  11. This is sort of on topic, read this latist diatribe by Mark Steyn and weep:


    McIntyre’s influence is clear.

  12. I repeat a post done over @ RC in response to one from Lady in Red, but there is some extra info, beyond the earlier posts on this:

    “This report was authored by Edward J. Wegman, George Mason University, David W. Scott, Rice University, and Yasmin H. Said, The Johns Hopkins University. We would also like to acknowledge the
    contributions of John T. Rigsby, III, Naval Surface Warfare Center, and Denise M. Reeves, MITRE Corporation.”

    1) WEGMAN is a distinguished statistician @ George Mason.

    2) David W. SCOTT is a distinguished statistician @ Rice, obviously asked by Wegman. In reviewing his C.V.:

    a) His C.V. references Wegman 6 times besides the Wegman Report:
    2 book chapters he wrote for Wegman-edited books, 1986 and 2005.
    4 sessions he organized in which Wegman was an invited speaker: 1987, 1987, 1989, 1990.

    b) Among his industrial consulting clients are Exxon and Dresser Industries (gear for oil&gas industries.) Of course, given his Houston location, that wouldn’t be odd. However, if one ranked cities in their concern about AGW, I suspect Houston would not be high on the list.

    All of this may be totally irrelevant, and Scott is certainly a distinguished statistician … but I’d think any useful social network graph would strongly connect him and Wegman, even if there are no co-authored papers.

    3) YASMIN SAID (Johns Hopkins) … got her PhD in Statistics from GMU, PhD Advisor = Wegman.

    4) JOHN T. RIGSBY III (Naval Surface Weapons Center) was doing his MS in Statistics 2001-2005 @ GMU, likely part-time while @ NSWC.
    http://www.linkedin.com/pub/john-rigsby/6/4b1/917 says he was doing MS then.
    Google Scholar: wegman rigsby yields
    King, Rigsby, Bernard, Wegman 2004
    Said, Wegman, Sharabati, Rigsby 2008

    5) DENISE REEVES (MITRE) did her final PhD Defense @ GMU May 19, 2009. Her dissertation advisor was Wegman.

    How strong a link is 2 senior people having know each other for 20+ years? Does a senior professor have any influence over a recent PhD student, a then-current PhD student, and a recent MS student with whom he had already written one paper?

  13. Dear DC: this is a different topic, but related in terms of your methods in uncovering the source of an error. The author does the same sort of textual analysis to trace the connections from one source back to others. A very interesting read.

    Considering the difference in purpose and scope of use between the Wegman report and the IPCC reports, I think you will find this to be even more significant.

    [DC: I’ll check it out. P.S. Your other two comments were very long, and possibly straying away from the topic. I’m inclined to let them through, but since there is considerable implied criticism of me, I will only do that when I have a chance to respond. So that may take a while.]

  14. Daniel J. Andrews

    Yes, it is a gratuitous weakening of the statement. They just can’t help themselves.

    Ah, thank you. I see it now. Just because you have not cited/referenced a source does not entitle you to alter what that source says especially if you’re going to copy it so closely, as Wegman has done.

  15. Andrews, you just do not get it. Wegman did not just change the wording, he changed the meaning of the text and if that were not bad enough also introduced errors. Big difference compared to paraphrasing something. You just do not change science willy-nilly to suite your agenda. The fact that Wegman did so indicates bias– the panel should have been impartial. Yet, the whole tone of the document is such as to undermine the credibility of Mann’s work and dendrology in general. Impartial my…

    Now if Dr. Jones, for example, were hypothetically caught doing the same as Wegman or Rapp, you probably would have been all over it over at WUWT or CA. You really do nicely show your own striking bias and agenda with comments like you made at 4:20 pm.

    According to your post you agree that Wegman “copied” text without referencing it. That is called plagiarizing Andrews, and it is a big no-no in science.

  16. Just wondering: “A Divergence Problem”?

    A deliberate play on words…? It would seem to be an allusion to how Bradley’s text was lifted but then altered by the Wegman gang to suit their purposes but with unintentional errors introduced at every step. Did you intend something along these lines?

    [DC: Yes, it was deliberate play on words.]

  17. I think the world just passed by your window.

    Pls take the time to read the comments on the von Storch op-ed.

    There is no point to you.

  18. I think the world just passed by your window.

    Pls take the time to read the comments on the von Storch op-ed.

    There is no point to you.

    A discouraging number of young people continue to take up smoking.

    This doesn’t make smoking harmless … nor does it mean people should stop trying to spread the truth about the harmfulness of the practice.

  19. You people can’t be serious about this. This reads like a satire on the perils of Internet blogging

  20. You’ve misquoted Wegman above.

    You report that he states, “Both tree ring width
    and density data are used in combination to extract the maximal climatic temperature.”

    What he actually states is this:

    “Both tree ring width and density data are used in combination to extract the maximal climatic temperature signal.”

    [DC: You are correct, and that error has been rectified. The post has reverted to the original commentary.]

    What’s more, no where does Wegman claim to be representing Bradley’s views, so your attempt to show that he has egregiously misrepresented those views is completely off-base.

    [DC: It’s true that Wegman has not stated that Bradley is the source for the tree-ring passage; in fact, he has failed to attribute any of it properly. But there can be no doubt whatsoever that the material is derived from Bradley, whether directly or indirectly.]

    But worse than all of that is the fact that this whole line of attack is pure ad hominem and thus totally fallacious.

    Wegman’s expertise (or any lack thereof) in discussing how tree ring reconstructions work is completely irrelevant to his competence to assess the validity of the statistical arguments offered by McIntyre and McKitrick — and it is completely irrelevant to the validity of those arguments, which validity Wegman clearly confirms.

    DeepClimate, you are wallowing in the shoals if ad hominem is all you got.

    [DC: I fail to see how pointing out the provenance of Wegman’s tree-ring passage, and the errors and distortions within it, can constitute an ad hominem attack. Wegman should have confined his report to the narrow, purely statistical question of whether Mann’s PCA technique was valid. But he went well beyond that. For instance, see Finding 7, which is based in part on the missing “low frequency” argument.]

  21. Wegman should have confined his report to the narrow, purely statistical question of whether Mann’s PCA technique was valid. But he went well beyond that.

    Wegman didn’t even do a complete analysis of the PCA technique. Had he done that, it would have been clear that Mann’s suboptimal (non-centered) PCA step had virtually no impact on the final results. By failing to quantify the impact of Mann’s PCA step, Wegman left the mistaken impression that the “hockey stick” may well have been a PCA artifact, when it is very clear that it wasn’t.

  22. Comments are temporarily closed but will reopen soon. Meanwhile, Merry Christmas and happy holidays to all.

  23. Comments are once again open on all threads.

  24. David A. Burack

    In the context of the Wegman report, it seems sensible to me that he re-stated the theory and science as recounted by Bradley, with or without attribution. It served as both a record of his own understanding– including any misunderstandings which are open to DC’s in some places perhaps well founded criticism– as well as a way to introduce the outside readership to the issue. I can see myself doing something like that, taking notes on the case to be analyzed, then writing them up as part of my report. Don’t see the beef here.

    As for the use of the word “relatively” to modify the strong signal statement, that actually could be taken to strengthen the assertion, not weaken it, i.e., The ring width signal is strong relative to other factors.

    This DC post seems to be grasping at straws.

    [DC: Typos edited at reader’s request.]

  25. DC: a modest suggestion, and I know this is a bunch of work, but in doing these comparsions, you might find it useful to:
    a) Number each of the sentences of the section of the Wegman report, i.e., [1], [2]. with the appropriate font.
    b) Number each of the sentences of Bradley, but with [1a], [1b], etc for extra ones.

    That makes it easier to refer back, and to summarize the comparison.

    [DC: It’s a good idea, but I won’t be able to get to that right away. There are a number of complications as well – for instance the sentence numbering would have to refer to the Bradley excerpts I found that correspond to Wegman, not the original which is much longer. Also Wegman and Bradley each have sentences that do not occur in the other.]

  26. Daniel J. Andrews

    I tried responding earlier to Maple Leaf but comments were closed so just dropped a quick post at RC where he had posted.

    But for the record here…

    ML–you’ve misunderstood my post badly. Perhaps I was unclear, or perhaps you misread it. Either way you arrived at the wrong conclusion. My stance is pretty much that of the scientists researching climate and what is found in the IPCC report (except changes are happening quicker than originally reported).

  27. re: numbering
    Well, it is clearly extra work, so it’s just a thought for the future.
    Note that I suggested numbering the sentences of Wegman, not Bradley, for the exact reason you mention. Hence, the algorithm is:

    a) Number every sentence in this section of Wegman.
    b) For every sentence in Bradley that is direct or paraphrase, give it the same number #.
    c) For every remaining sentence in Bradley that is worth mentioning, give it [#a, #b] where # is chosen from the immediately previous #.

    At this point:
    a) Not all #s in Wegman have correspondences in Bradley.
    b) All simple #s in Bradley have correspondences in Wegman.
    c) The #a’s in Bradley do not have correspondences.
    d) The #s in Wegman are in order.
    e) The #s in Bradley are mostly in order, but likely good enough to ease quick locatio

    Your formatting already essentially does this. it just doesn’t have the terse identifiers.

  28. are you guys in a time warp? The Wegman report was what like 5 years ago? The news today is climategate and the massive deception. Get with the times.

    [DC: The Wegman Report was three and a half years ago. In a way, it was the precursor to Climategate – the same deceptive, phony charges against climate scientists.

    If you are interested in Climategate, then you should read my latest post on that subject:


    Please read the posts carefully and try to keep your comments on topic. Thanks!]

    • People keep bringing up the 1998 hockey stick paper as if it was the central plank of the evidence from the IPCC for global warming. So why don’t you go and tell them to get with the modern findings?
      (Which pretty much confirm the hockey stick…)

      [DC: They also bring up MBH 1999, although many don’t even seem to be aware of the difference between the two papers (MBH 1998 only went back to 1450).

      AR4 Chapter 2 and Mann et al 2008 in PNAS constitute the most up to date paleoclimatological science.]

    • I would add Mann, et al. 2009: Science 27 November 2009: Vol. 326. no. 5957, pp. 1256 – 1260

      Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly

      Michael E. Mann, Zhihua Zhang, Scott Rutherford, Raymond S. Bradley, Malcolm K. Hughes, Drew Shindell, Caspar Ammann, Greg Faluvegi, Fenbiao Ni

  29. Another thing that’s bothered me about the Wegman report.

    Its official title is : “Ad Hoc Committee Report on the ‘Hockey Stick’ Global Climate Reconstruction” (DC omitted “Global Climate” above).

    The hockey stick is, of course, a reconstruction of northern hemisphere temperatures. That doesn’t say much about their thoroughness.

  30. I’m surprised it has taken warmies this long to bring out the character slurs against Wegman.
    Normally, the AGW groupies are off and running with the ad homs within 5 minutes.

    But how dare Wegman ask any questions. Doesn’t he know that cosy peer-review where no one even checks the original data is the “gold standard” in climate research?

    [DC: Most of the post concerns the low standards of scholarship in the Wegman Report, which are surely beyond debate on the above evidence. As for my characterization of the report as “politically motivated”, that is clearly supported by the provenance of the report.]

  31. “Another thing that’s bothered me about the Wegman report.

    Its official title is : “Ad Hoc Committee Report on the ‘Hockey Stick’ Global Climate Reconstruction” (DC omitted “Global Climate” above).” – cce

    It’s never bothered the warmies who have loudly and persistently claimed that the last century has been the warmest *globally*.

    They could never be bothered to make the distinction between the Northern and Southern hemispheres and I have never, not once, heard a warmie bothered by that flagrant misrepresentation of the science.

    [DC: The “hockey stick” reconstruction was indeed for the northern hemisphere.

    “It’s never bothered the warmies who have loudly and persistently claimed that the last century has been the warmest *globally*.”


    Average Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than during any other 50-year period in the last 500 years and likely the highest in at least the past 1,300 years.

    So, the only “flagrant misrepresentation” here is Wegman’s … and yours. Obviously, you can not continue to do that here.]

  32. Hahaha! Funny..

    I actually followed your “Let the backpeddling begin” link thinking you were actually going to write a retraction of THIS (or actually the former thread you yanked) aticle.

    For those who don’t know what I’m talking about, DC accused Rapp of plagurizing the Wegman report, and Rapp threatened to sue.


    The article was gone and replaced with this tripe.


    [DC: You are looking for this post.]

  33. But how dare Wegman ask any questions.

    He’s free to ask questions. We’re free to point out when his answers to those questions are cr*p.

    [DC: True enough. But not only that, I have some questions I’d like to ask *him* some time.]

  34. “[DC: You are looking for this post.]”

    Umm no. [Link to Google cache snipped as I do not wish to propagate possibly erroneous information.]

    [DC: An earlier version of this post speculated that Rapp may have collaborated with Wegman. After Rapp’s vehement denial of that collaboration, yes, I did remove that speculation, as noted at the beginning of the article.

    However, that leads to the inevitable inference that Rapp copied Wegman section 2.1 without attribution. That implies possible plagiarism on Rapp’s part, which the previous version of the post did not. Also note that Rapp himself has admitted that he did not give proper attribution for the sections at issue.]

  35. “So, the only “flagrant misrepresentation” here is Wegman’s … and yours.” – DC

    [DC: Your unsubstantiated allegations of “misrepresentations” by “warmists” are off-topic and inflamatory. Please confine comments to the actual science, and Wegman’s critique of it.]

    And that you would call Wegman’s phrase “flagrant” goes to the heart of how far AGW advocates will stoop in attempting to discredit any questioning of AGW.

    [DC: The mistake in the title of Wegman’s report is only one among many misrepresentations. I’d say these misrepresentations do rise to “flagrant” on the basis of available evidence.]

    “He’s free to ask questions. We’re free to point out when his answers to those questions are cr*p” – dhogaza

    Again, no one has ever been “free” to ask questions since post-Kyoto. As an emergent orthodoxy, any questions have been seen as a threat to the core science, beliefs and unverifiable projections that constitute the so-called “settled” AGW science.

    But, as Copenhagen demonstrated, AGW advocates have a very serious PR problem on their hands. Unwilling to answer any questions from the public, the public has wisely declined to give their democratic approval to radical action.

    With badgering, hectoring and bullying on the subject having failed, negotiations are back to square one.

    If I had any advice for AGW advocates, it would be to drop the tone of superiority and start answering any and all questions the public has.

    [DC: I agree that the contrarians and the forces attacking science and reason have won a PR victory, but not for the reasons you state. The falsehoods about climate science propagated by McIntyre and McKitrick, and echoed by the National Post, the Wall Street Journal, FoxNews and the rest have had an effect no doubt.

    But I remain optimistic that truth will win out over ignorance and greed. And that starts with asking the right questions to the right people. So far, McIntyre and McKitrick and their supporters have gotten an easy ride. That has to end.]

    • “Again, no one has ever been “free” to ask questions since post-Kyoto. ”

      What utter bollocks! People are asking questions all over the place. The problem is not the questions, the problem is the answers.

  36. With badgering, hectoring and bullying on the subject having failed, negotiations are back to square one.

    The view’s different from here in the US. Obama got what he needed in order to pass a bill in the Senate, China and India are at the table. The UN process is broken, but the US Senate wasn’t going to ratify a treaty, anyway. Non-treaty agreements can run through the Senate with at worst 60 votes for cloture (rather than 67 for treaty ratification).

    I’m not alone in this analysis. The Natural Resources Defense Council has put forward a similar analysis, as have others.

    Meanwhile, two days ago:

    A new Chinese law requires power grid operators to buy all the electricity produced by renewable energy generators, in a move that will increase the proportion of energy that comes from renewable sources in coal-dependent China.

    The amendment to the 2006 renewable energy law was adopted on Saturday by the standing committee of the National People’s Congress, China’s legislature, the Xinhua news agency said.

    The agony of defeat? Not!

  37. That is part of the problem DC. You consider all questions to be an attack on the science. It has been this way since Kyoto.

    The “science” was delivered as an ultimatum to citizens. Correctly, we have rejected the ulimatum.

    [DC: You haven’t asked a question yet, as far as I can see. You have made unsubstantiated assertions, including the above one about a supposed ultimatum “delivered” by scientists.]

    Secondly, you consider yourself on the side of “truth” and against “ignorance and greed”. Seriously, isn’t everyone?

    [DC: I consider Marc Morano and Tom Harris on the side of ignorance and greed. Certainly not on the side of truth. Moreover, I have documented many falsehoods and errors emanating from the likes of McIntyre and McKitrick, among others. They resolutely refuse to correct their own errors and those of others relying on them. If you want to discuss details of those previously documented, please go to the appropriate post and ask questions or make comments there. Thanks!]

    However, activists consider themselves special, and above ordinary citizens, which is why they have attempted to force this agenda on citizens without first winning their approval. Sorry, we the citizens call the shots.

    We’ll ask as many questions as we like and if don’t get answer without insults, well, we will prevent any radical action on AGW until then.

    [DC: Last time I looked, the political parties accepting climate science and the need for effective action were in the majority in both Canada and the U.S. I suppose those opposed to science will keep “asking questions” and perpetrating falsehoods until they get the answers they like or manage to elect enough obstructionist legislators.

    Whatever happens, I’ll keep asking the real questions that need to be asked.

    In future, please try to stay on topic with more focused and relevant comments. I have been very patient with you so far, but you are fast wearing out your welcome. ]

  38. Haha, the wegman report, I agree with Don, yesterdays news, but still damaging enough. Bringing up the wegman report is like arguing who will win last years election. Go Dion Go.

    You must be running out of material and doctored evidence to support global warming hysteria.
    Keep it up though, I always get a good laugh from the posts.

    [DC: As far as I can tell, it’s Climategate “yesterday’s news”, or rather last century’s news: recycled talking points about the the 1999 “hockey stick” (and 2001 IPCC TAR) based on selective quoting and misinterpretation from emails written in 1999.

    And, no, I haven’t run out of material. There is no end to the perfidy of the contrarians, unfortunately.]

  39. “However, activists consider themselves special, and above ordinary citizens, which is why they have attempted to force this agenda on citizens without first winning their approval. Sorry, we the citizens call the shots.”

    And why do you think the citizens don’t believe in AGW in large numbers? It is because of the disinformation campaign against science from people like Wegman.

    Wegman was supposed to be some “independent” observer, but now we have learned that this isn’t the case:

    1. Wegman changed the meaning of his source material to conform to his ideological goals.
    2. Wegman’s panel consisted of a tightly knit “social network”–far tighter than any he alleged in his nonsensical “social network analysis.”
    3. Wegman is willing to punt away his statistical credibility by signing onto a statement that included the absurd claim that “Global warming stopped in 1998.”

    Now, combine that with apparent plagiarism of Bradley that would get any freshman comp student an F and you have to wonder why anyone would listen to anything Wegman says.

    • Boris,

      I know this is long after the event but I have to mention what happened at Lucia’s

      I’ve always thought that Lucia was one of the more reasonable “sceptics” but no longer. She was being willfully stupid throughout and then this:-

      You said

      Boris (Comment#29209) December 26th, 2009 at 12:41 pm
      If you can’t see that Wegman’s sentences are nearly exactly the same as Bradley’s, I don’t know else to say.

      (My emphasis.)

      She replied

      lucia (Comment#29212) December 26th, 2009 at 1:58 pm
      Are you actually claiming your three examples are “exactly the same”? Do you know the definition of either “exactly” or “the same”?!

      followed by a long screed. You’d think that someone would read what you actually said before making that obvious strawman attack. Did you not notice? She either lied or can’t f***ing read!

      (Comments closed in early Jan)?

    • TS (and any others interested),

      Here are the detailed sources for Wegman et al’s section 2.3.

      Click to access wegman-social-networks.pdf

      I’ll probably do a short post on this at some point.

  40. [DC: That’s enough off-topic and repetitive generalizations about “activists” and “eco-offenders”. If you don’t have a relevant point to make about Wegman’s report or other specific issues raised about Wegman, then please don’t post.]

  41. DC: you may want to become more familiar with George Mason University, as I’m not sure if there’s a Canadian analog.

    See Sourcewatch on GMU, for example, and note that its Institute for Humane Studies had a a person we know:
    1994-2000 Distinguished Research Professor, Institute for Humane Studies at George Mason University, Fairfax, VA : Fred Singer.

  42. It’s also worth noting that the Wegman Report came out 7 and 8 years after MBH99 and MBH98 respectively.

  43. Sorry, we the citizens call the shots

    Sounds like a manifesto for the anti-science brigade :

    “If we citizens don’t like the science, we say BURN THE SCIENTISTS !!”

  44. Oh, come on! Mann and Tamino both cited Ian Jolliffe in support of MBH and when Jolliffe found out, he destroyed their claims. Isn’t it time to give up on that dead horse? Just who are the denialists here?

    • Presumably you are referring to the use of “short-centred” PCA in MBH98. This is a valid, but relatively, minor point. Wahl and Ammann demonstrated that proper application of conventional PCA would not materially affect the MBH reconstructions. Ian Jollife has not disputed this point.

      See this comment for further discussion.

      Having said that, I want to keep discussion focused on Wegman’s appropriation and distortion of material from Bradley. Thanks!

  45. Brian Macker

    Social networking doesn’t matter when you are writing a paper together. It does matter if you are a supposed critical reviewer. Your remarks about Wegman’s relationship with his coauthors is stupid.

    [DC: I would point out that Wegman’s social network analysis was itself confined to Mann’s co-author network. His comments about climate science reviews were purely speculative.

    On the other hand, for a real documented case of reciprocal friendly review and editing look no further than the contrarians. Chris de Freitas as editor of Climate Research greenlighted the deeply flawed Soon and Baliunas paper on MWP, after Baliunas had acted as handpicked reviewer of a de Freitas article in the Bulletin of the Canadian Society of Petroleum Engineers a year earlier.]

  46. Are you being deliberately ironic with that last comment, or have you not read the Climategate emails?

    [DC: The most egregious breakdowns and examples of corruption of the peer review process are clearly on the contrarian side. If you want to discuss those problems, please go to the relevant posts and comment there.]

  47. ” I’ve just completed Mike’s Nature trick of adding in the real temps
    to each series for the last 20 years (ie from 1981 onwards) amd from
    1961 for Keith’s to hide the decline. ” – Phil Jones

    Let me get this straight: you’re claiming that the decline to be hidden was not in the second half of the twentieth century?

    I must be very stupid because I don’t understand that.

    [DC: McIntyre claims that Mann, as IPCC TAR lead author, pressured Keith Briffa to “hide the decline” in Briffa’s contribution to a key IPCC graphic. What I have shown is that Briffa had already published a curve very similar to the one that was eventually published. So McIntyre’s accusation is sheer nonsense. Even Chip Knappenburger agreed that McIntyre was wrong, and tried to talk McIntyre out of it, without success apparently.

    Jones’s email had nothing to do with the IPCC report, despite McIntyre’s attempts to tie it in.]

  48. DC, your W and A comment is not totally true. Yes, if you go to the 4th PC, and retain that, Mann’s algorithm will still train on that for the final recon.

    But his paper actualy made comments about the FIRST PC and the DOMINANT MODE OF VARiance (I’m not direct quoting, but you get the point). Those claims about the first PC were WRONG. WRONG, WRONG. So, with standard methods it turns out that what was trained on was not even the primary signal!!

    [DC: Yes the first PC was wrong, using short-centred method. But PCA doesn’t preordain the number of PCs to retain. To me, that’s the takeaway from Wahl and Amman. If conventional PCA in W&A had not led to a highly similar reconstruction as MBH98/99, then I would agree that would have been much more devastating for the MBH result.

    As it is, it was a valid but ultimately not very significant criticism, in the larger sense of assessing millenial paleoclimatology. Even your hero von Storch agreed with that, IIRC.]

  49. Every time I read one of the warmist “refutations” of something I feel like I’ve been time warped into some sort of twilight zone where normal English is transmuted into something. . . funny. Really, I’ve actually read the Wegman report. To boil it down and put it quite simply and clearly, Wegman applies rigorous statistical (admittedly, on his part, not climatological) criteria to the Mann et al analysis and finds that it comes up wanting. He sides with much of McIntyre’s critique, where he understands it, but not all of it. And, as the preponderance of evidence indicates, he thinks that statistically, the AGW arguments tread far beyond the parameters that normally apply to data with high variance where rigor is required, and that the hockey stick, for one thing, does not hold water. That is the clear story that I read. Now, what did you read?

    [DC: As I’ve said before, Wegman’s (and McIntyre’s) one valid point is that individual PCs were incorrectly calculated. However, Wegman failed to answer the obvious question – what impact would correct application of PCA have on the MBH reconstruction? And the answer, as far as I can see, is very little. Wegman also betrayed basic misunderstanding of climate science in some of his overreaching findings. ]

  50. I don’t understand “understanding climate science” or not. If you’re measuring something historically and doing a predictive analysis based on the past, why would you need an understanding of climate science — at all? It seems in that instance The Most Important Uniderstanding would be handling the numbers correctly, knowing how to not over- or under-anticipate. It would be a simple matter of this is what was; therefore, this is what will be.

    [DC: Handling numbers “correctly” with poor understanding and knowledge of the domain in question is not good science. The fact is, if PCA is done correctly, there is little impact on the resulting reconstruction. Zeroing in on one step, without looking at the overall picture, smacks of bias, quite frankly.

    Rest is off topic – I’m getting very picky about moderation.]

  51. And, as the preponderance of evidence indicates, he thinks that statistically, the AGW arguments tread far beyond the parameters that normally apply to data with high variance where rigor is required, and that the hockey stick, for one thing, does not hold water.

    This is where you’ve gone wrong, because he stopped short of that. He didn’t perform the analysis to determine what impact the error he uncovered would have, as DC said.

    In other words, he said, “I found an error”, without showing if it was an *important* error, or not.

    If I add 50 + 50 and get -100, I’ve made a very large error. If I get 99.999999 … not so much.

    Other researchers went back, redid the work using standard PCA analysis blessed by Wegman, and got …

    the same friggin’ hockey stick.

    That is the clear story that I read. Now, what did you read?

    What’s important is what you *didn’t* read, i.e. what Wegman left out – any analysis of the actual impact of the error.

    Got it?

  52. Back to Dhogza’s earlier comment that “Other researchers went back, redid the [Mann et al MBH] work using standard PCA analysis blessed by Wegman, and got … the same friggin’ hockey stick” prompting my question: who, when…?

    I found a question similar to mine on Steve McIntyre’s site, today, with his answer:

    1.“Is there a corrected MM2003 using the actual MBH98 method and different proxy data selection?

    “Or is the MBH98 method still closed to inspection?

    “Steve: There has been extensive work on MBH. Our results reconcile to Wahl and Ammann’s. There are some remaining mysteries: MBH provided source code when requested by the House Energy and Commerce Committee but didn’t include code for their retention of principal components – a battleground issue – or calculation of confidence intervals. Climategate Letters shed some light on confidence interval methods, but this is on the “dig here” list. Their principal component retention remains a mystery. But the underlying issue is the validity of Graybill bristlecone chronologies as a unique radio antenna for world temperature.”

    Frankly, I don’t understand the answer, technically, but it sounds like MBH is still, after all these years, refusing to show their hand, explain what they did and why, openly. Is McIntyre’s answer incorrect?

    [DC: Yes. The issue of retention of principal components is key and McIntyre has never properly addressed it. The retention of PCs would not necessarily be coded – in many cases it’s a more nuanced judgment call based on the results. What is clear is that retention of only two PCs using “conventional” PCA in the case of the MBH data set makes little sense. McIntyre should finally acknowledge that]

    (Which brings me to my earlier question about your understanding and analysis of the CRU Harry_Read_Me files. Are they reflective, in your estimation, of quality science? Are they typical of mainstream climate scientist research?)

    [DC: No. But this whole line is another bogus issue, in my opinion.]

    If this is off-topic, you may, if you wish, retain the message and use it when it is appropriate to move beyond the present student tree-ring importances and understanding and verbiage.

    I would be happy to see you address the questions. ….Lady in Red

  53. Pingback: Steve McIntyre and Ross McKitrick, part 2: The real story behind the Barton/Whitfield investigation and the Wegman Panel « Deep Climate

  54. Jesus. Talk about grasping at straws.

    As an aside, your response to the post just above: “The issue of retention of principal components is key and McIntyre has never properly addressed it.”, is a bit off the mark. It seems pretty clear that she was asking if MBH had ever addressed their criteria for retention of PCs, not McIntyre. After all, it is their data and their methods, not McIntyre’s. It is their place to address the issue, if anyone is going to.

    [DC: It is addressed in MBH98, as well as Wahl and Ammann. But, as far as I know, it’s not mentioned in any of the three M&M papers, nor in Wegman et al. Thus, this is a significant error in the M&M analysis and “correction” of MBH98.]

    But back to what I had started to say. I read your side-by-side comparison and had to laugh. As far as it goes, I agree with you that Wegman should have identified the source of a great deal of his information. If he did not, then shame on him. But that is the only error I see here. It certainly does not call into question the quality of his conclusions.

    [DC: Some of Wegman’s findings flow from mistaken assertions in this section, as I have explained previously. ]

    You make a big deal out of Wegman’s adding the bits about CO2, but apparently you don’t see fit to mention that what he states about it in those additions you so deride happens to be true. So his adding those statements is not an error or distortion, it is simply a matter of including additional information in his report that is very much relevant to the issue. In at least one place Wegman clearly cites his source for those comments about CO2. If you have an issue with their inclusion, you will first have to refute the source before you have any legitimate cause to berate Wegman for including them.

    And what is your problem with Wegman’s statement that there are “many confounding factors”? The fact that there are, in fact, many confounding factors is self-evident from the very material presented. I count at least 9 confounding factors in Bradley’s own paragraph. So what’s your problem? You don’t think 9 or more qualifies as “many”? That’s merely your interpretation of English usage, and does not qualify as a judgment of the science involved.

    [DC: The problem is we don’t know the provenance of any of these assertions. Material from Bradley has been mixed up with apparent errors and distortions of unknown provenance. You can twist and turn it as you like, but if one author wants to criticize another, it should be done explicitly and the sources and reasoning given. That’s called scholarship.

    No one even knows (other than whoever drafted this section) if Wegman got the Bradley material directly from Bradley, or some intermediate source. That’s a huge problem. ]

    In fact his emphasis on confounding factors is absolutely relevant to the point. There ARE confounding factors. Many of them. That is fact. If those confounding factors are not somehow adjusted for, then how well measurements of the tree rings correlate with actual temperature is little more than a GUESS, and likely not a good one. I strongly suspect that there is not enough existing information about those factors to allow real compensation for them; which would mean the tree proxy data amounts to just that: guesses. I could be wrong, but so far I am not aware of anybody coming forth to explain those compensations.

    You make a big deal about Wegman adding the word “relatively” to one passage. Again, I had to laugh. In fact Bradley SHOULD HAVE used the word “relatively” there. The temperature component is still subject to other confounding factors; the only way that the temperature component will be “strong” instead of “relatively strong” is, again, if those confounding factors can be factored (no pun intended) out.

    You make an issue of Wegman leaving out the part about regional data being used to reduce the effects of confounding factors. There was nothing improper about that. The temperature proxy data from the MBH98 and MBH99 data were drawn from relatively few samples; to the best of my knowledge there was no “regional data” available from which to make such adjustments. Therefore the whole topic is irrelevant to the issue at hand, and it was quite proper of Wegman to leave it out.

    [DC: You’ve misunderstood the point here. Wegman’s exposition glosses over the difference between an individual tree-ring proxy sample, and a series based on a collection of samples from one site or site cluster. Again, how did this happen? What source was Wegman working from for this passage?]

    In these particular circumstances I question the existence of the kind of equation mentioned by Bradley to describe variability, and even if there were one, I would question its veracity. In order for an equation to function as Bradley describes, the confounding factors of the interval instrumentally measured would have to be the same as those of the period the paleo tree rings were formed.

    But there is a stumbling block interfering with that idea: a central part of the MBH claim is that the conditions are NOT the same now as they were then. This leaves them in something of a quandary: simple logic dictates that if their hypothesis is correct, then they have no way of knowing whether an equation they use for calibrating the paleo data is correct.

    Therefore Wegman’s discussion of confounding factors is not specious. Rather, it is an important issue that to date has not properly been addressed.

    Have those confounding factors actually been addressed somewhere without my knowing about it? Possible. But if so, I would be interested in knowing where that information is so I could read about it.

    [DC:A good tree-ring website is here. That’s a much better starting place for knowledge, than Wegman’s hopelessly muddled exposition. Good luck!]

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