Hughes on Australian ABC

The Australian Broadcasting Corp. had an interview with Malcolm Hughes on Apr 5 when he once more attempted to blame the messengers for identifying the shortcomings of their own statistical methodology. We eagerly await the Dendro Truth Squad rebutting this “misinformation”.

But first some comments by Hughes on bristlecones which are germane to our discussion of upper treeline proxies. He described bristlecone environment as “wickedly dry” – something that one would think would be a disadvantage in disentangling termperature:

And the problem there was, remember I told you they live in high, cold, dry places, they’re really wickedly dry places actually, less than 500 millimetres of precipitation a year, even in very high mountains.

He conceded that dendro-ists could do better with cold years than warm years, something that few readers here would disagree with:

if they’re at a lower elevation place and they’re limited by moisture then we can usually do a pretty good job of the driest years and not do a bad job of the moderate years, and a poorer job of the really wet years, because if you’ve got enough you’ve got enough and you’re not going to get any bigger, then we’d have to use other things in the size of the rings. Likewise with temperature, you can usually do a better job with tree rings of nailing down the cooler years than the warmer ones.

We still haven’t seen any formal discussion by Hughes of the U of A seminar topic Why are Upper Elevation Bristlecone Pine Really Growing Faster?, but maybe his interview gives some clues. Hughes claims that, in their consideration of bristlecones, they “set the last century aside”: because they are unable to allocate 20th century growth between warmer temperatures, CO2 fertilization and even nitrogen fertilization. Hughes:

One of the things that we set aside in our work about the bristlecone pine … and their effect on climate, was the last century. And the reason we set the last century aside is because these trees have been growing faster since the early 20th century than any time in the last 5000 years and we have this nailed down very firmly. It’s been known broadly for 20 years but we’ve taken a lot more samples, analysed a lot more wood and we’re seeing very, very clearly that something extraordinary is happening and at the moment we only have a partial idea of why it is happening. So to what extent this is warmer temperatures, to what extent this is direct fertilisation of the tree growth by increased atmospheric carbon dioxide I wouldn’t want to say just now.

In addition to CO2 fertilization, Hughes noted the possibility of nitrogen fertilization:

…. Well, there’s a couple of other possibilities, which is nitrogen; these plants are growing in tough conditions. Anyone who gardens knows you may need to add some nitrogen, we may have done that by populating California 100, 150 years ago. These trees are some hundreds of kilometres downwind of LA. If fog or smog can get to the Grand Canyon from the LA area it should be able to get to eastern California, too. So we haven’t completely ruled that out either.

The trouble is this: MBH didn’t “set aside” the last century in their discussion of bristlecones. The effect of Mann’s PC methodology, as has been endlessly observed, was to enhance the impact of bristlecones – a proxy which prior to Mann (and Hughes) had been avoided in multiproxy reconstructions and which the NAS Panel has said, once again, should be “avoided”.

But the Team is addicted to bristlecones and their interbreeding cousin, foxtails. Mann’s PC1 and bristlecones was used in more studies in 2006 than in any previous year (Osborn and Briffa 2006; Hegerl et al 2006; Ammann and Wahl, in press; and Juckes et al, status ??) In our discussions with Juckes on this blog, you can see how tenaciously the Team fights to hang on to bristlecones because their distinctive HS shape is important to yielding a HS reconstruction. So for Hughes to tell the Australian audience that they “set aside” bristlecone growth in the last century is, in Rob Wilson’s phrase, “misinformation” and I’m sure that the Dendro Truth Squad over at the Arizona listserv will pursue this vigorously.

The other problem is that Mann knew that there was no HS without the bristlecones (as evidenced by the CENSORED directory) and yet, as late as 2000, claimed that their reconstruction was “robust” to the presence/absence of all dendro series, while knowing that it was not robust even to the presence/absence of bristlecones, again a point that the Dendro Truth Squad has been strangely silent about.

Hughes speculates that the attention paid to the MBH hockey stick derives from its use by IPCC, as though that were a great insight. He doesn’t need to speculate on this. OF course, that’s the reason. It was also not used incidentally but featured prominently in the IPCC press conference releasing the WG1 report and just as prominently by governments. Kurt Cuffey of the NAS Panel said that IPCC “oversold” the hockey stick. Here’s Hughes feeling sorry for himself:

I think, and this is my interpretation, I don’t have anything other than supposition to support this, I think our particular diagram attracted the attention because it was used as figure 1b of the Summary for Policy Makers of the previous Intergovernmental Panel on Climate Change report 7 years ago. Had somebody else’s diagram, and there were a couple of other possibilities with the same findings, then they would have been the subject of, you know, angry email from Retired Engineer from Woola Woola or statements by senators who might not know a scientific question from the back end of a rhinoceros. So, I think whoever’s work had been used to illustrate that point would have been subject to that attention and it happened, on this occasion, to be ours.

Here’s an amusing exchange between Robyn Williams, the Australian interviewer, and Hughes:

Williams: … But since then the Academy of Science has come out and said that the hockey stick is valid on all sorts of criteria and yet the critics have persisted. Why do you think they get away with it?

Malcolm Hughes: Well, I don’t know that they do get away with it.

Williams closed by saying:

And the US Academy of Sciences endorsed the hockey stick in a report published on June 22 last year. I’m Robyn Williams.

There doesn’t seem to be a “consensus” at the University of Arizona about this. Scott Saleska of the University of Arizona, one of the climate scientists who filed the Amicus Curiae in the recent Mass vs EPA writes on another thread,

Though I haven’t so far worked in the climate proxy field, I basically see what you are trying to do here as scientific in a fundamental sense: evidence based inquiry, without accepting the say-so of anybody no matter their authority.

Whenever I look at this site … I am reminded of the saying that I think I first saw on the Splus news list: “In god we trust, all others must bring data.”) CA certainly is more scientific in terms of representing the actual ongoing (sometimes messy) process of ongoing evidence-based inquiry than any blog I am aware of. I read your GRL paper when published, thought it a reasonable criticism at the time, and noted that the NAS report did basically endorse it.

A third University of Arizona scientist, Matthew Salzer, has also recently opined on my work, complaining that I “broke the rules” – without specifying anything further. Maybe he meant that I broke the rules by trying do science “in a fundamental sense: evidence based inquiry, without accepting the say-so of anybody no matter their authority.” No wonder Rob Wilson thinks that it “could be dangerous to leave Steve McIntyre unchecked”.

[By the way, the NAS Panel did not endorse the MBH hockey stick any more than Stephen Jay Gould endorsed the Piltdown Man. Believing in evolution does not and did not oblige scientists to accept the Piltdown Man.]

Eduardo Zorita said at the time that the NAS Panel report was as severe a criticism of Mann as was possible in the circumstances. The NAS Panel certainly believed that it was “plausible” that the modern period could be shown to be warmer than the medieval period on alternate grounds than MBH, but accepted every one of our specific criticisms of MBH. Our papers did not comment one way or the other on whether some other set of data might resolve this issue, only that MBH didn’t. At the blog, I’ve observed that each of the other Hockey Team reconstructions likewise has fatal problems, but again I do not preclude the possibility that some future paper using better analysis (or more likely new and better proxies) may resolve the question.

I might add that several talented young scientists at AGU privately agreed that the various Hockey Team reconstructions were dead (they were not prepared to be identified publicly), but it’s gratifying to even get private acknowledgement from young scientists.


  1. Stan Palmer
    Posted Apr 6, 2007 at 9:23 PM | Permalink

    The fact that they are talking about your work shows that you have succeeded. Paul Feyerabend would have been pleased to us this as a clear example of his philosophy.

  2. Follow the Money
    Posted Apr 6, 2007 at 10:14 PM | Permalink

    “could be dangerous to leave Steve McIntyre unchecked”

    Threatening hockey allusion provoked by the many goals you’ve scored. Keep up the good work.

  3. JMS
    Posted Apr 6, 2007 at 10:24 PM | Permalink

    Steve, once again I have to say that you are misrepresenting this interview. Most of the interview was a discussion of the current state of Hughes’ research and only the last 5 minutes or so was devoted to a discussion of the hockey stick. Hughes’ discussion seemsed to focus on what they have learned in the intervening DECADE since the original report. After reading the NAS report myself, several times, you were somewhat vindicated in two aspects of your critique; the centering issue and the bristlecons issue, but I think that they basically vindicated original study at the level of confidence claimed in MBH99.

    Hughes had a lot of good points about how science works that you just choose to ignore — MBH98/99 was far from the last word on this subject — it in fact was just about the first word, and there has been a lot of work on sorting out the various factors which affect tree growth since then (although I disagree with Hughes characterization of the source of N fertilization, it more than likely comes from farming in the Central Valley of CA — not LA. Prevailing winds tend to be pretty much E-W or NW-SE in this region, not SW-NE).

    And as far as Steven Jay Gould endorsing the Piltdown Man, if anyone had given a s**t about the reality of Piltdown Man they would have seen that it was a hoax. Need I remind you that the last artifact taken from the supposed Piltdown Man site was a cricket bat, a clear indication that someone was trying to say that the thing was a hoax. Do you really believe that climate science is a hoax? I thought not.

  4. bender
    Posted Apr 6, 2007 at 10:26 PM | Permalink

    Steve, you know I’m not one to cheerlead. But this is a Good Thing.

    Statistical reconstructions on bcps and the like just can’t be all that precise, the primary problem being model mis-specification, as outlined in “Wilson on brsitlecones”. It will take a physiologist to prove it, but if you cram the model:
    G = f(P + T + C + N + P*T + P*C + P*N + T*C + T*N +C*N + P*T*C + P*T*N + P*C*N + T*C*N + P*T*C*N)
    into model:
    G = f(T)
    you’re going to have huge innacuracies in the parameters and therefore reconstructed T. Especially if f is nonlinear.
    This is the conjecture that dendroclimatologists need to comment on. All else is secondary. Where is the “misinformation” here?

  5. tetris
    Posted Apr 7, 2007 at 12:10 AM | Permalink

    JMS: The Webster defines a “hoax” as “to trick into believing or accepting as genuine something false and often preposterous”. By systematically excluding substantial and growing bodies of scientific evidence that run contrary to its political dogma, while highlighting those that support its AGW hypothesis and preposterous extrapolations [all based on correlation-equals-causation nonsense], the IPCC as the body of purportedly internationaly vetted “climate science”, is de facto and de jure perpetrating a hoax. As someone with a PhD in a closely relevant discipline, 25 years of experience in risk assessment, corporate due diligence and former CEO/Chairman, I can assure you that if a private or public company were caught out trying to pull of an IPCC type hoax, its senior representatives would wind up enjoying the view of a row of bars from the inside out for a long time, indeed. The second IPCC “report” presented earlier today has all the requisite elements of a hoax. But because the IPCC is an NGO, those in charge of this ongoing scientific fraud remain unanswerable to anyone.

  6. Posted Apr 7, 2007 at 12:51 AM | Permalink

    “These trees are some hundreds of kilometres downwind of LA. If fog or smog can get to the Grand Canyon from the LA area it should be able to get to eastern California, too.”

    Having stood downwind of the Corona/Norco area on a damp evening, I can personally attest to elevated airborne nitrogen levels in Southern California.

  7. DaleC
    Posted Apr 7, 2007 at 1:17 AM | Permalink

    re #3 JMS,

    Your account of the interview is an ad hoc reaction of convenience. Your “last five minutes or so” is in fact 45.6% of the total.

    From the transcript:
    total number of words, 4,100
    number of words on HS, 1,868

    100*1868/4100 = 45.6%.

    I am amazed that you appear blind to the full implications of the HS disaster. The huge weight of contemporaneous historical and documentary evidence for the MWP and the LIA was blatantly ignored in favor of an artefact of poor statistics and mis-matched data, which was seized upon with glee by the 2001 TAR. Where were the supporting arguments to show that this body of evidence was wrong, fabricated, misunderstood, misinterpreted, or otherwise abused by the prior millenial reconstructions in the first and second assessment reports? Nowhere to be seen. Do you not understand the public disrepute the improper promotion of the HS has cast across the entire field? Do you not see how you categorize yourself as opportunistic and self-serving by defending this travesty? Do you not comprehend the abuse of authority by the IPCC in failing to publicly disavow the HS? The consequences are that the HS continues to be used by alarmists as if it were the rock solid truth (Lovelock to justify claims of our imminent extinction, Lloyds Insurance as an excuse to jack up premiums, my son’s geography text book to proselytize for the next generation of eco-warriors, etc etc etc).

    If, as you say “MBH98/99 was far from the last word on this subject ‘€” it in fact was just about the first word”, then can you please explain to me why such a provisional piece of research which flew in the face of all preceding understanding continues to be used as part of the justification for a global energy policy which will cost trillions?

    The whole HS affair is very depressing. I keep looking for reasons to be able to trust that, in the face of the unknown consequences of the ever-increasing human footprint upon our planet, the science is being conducted fairly, honestly, above board and with a proper concern for the well established principles of transparency and due dilligence, but when I read things like the Hughes transcript linked to above, I just get more depressed.

  8. DavidH
    Posted Apr 7, 2007 at 3:21 AM | Permalink

    Re #3,

    JMS is being selective in his reading. The most damming statement in the NRC/NAS report is on page 110 where they say.
    “Largescale temperature reconstructions should always be viewed as having a “murky” early period and a later period of relative clarity. The boundary between murkiness and clarity is not precise but is nominally around A.D. 1600.”
    They try to soften the blow by saying Mann’s conclusions are “plausible” which some people, who have not looked the word up, think is a point in Mann’s favor. It is not. In most dictionaries an element of deception is implied.

    Very telling are the replies of Gerald North and Ralph Cicerone to last summer’s US Congressional hearings in which they endorsed the Wegman report. See pages 84 and 735 of the (150MB huge) transcript which is at:

    Click to access getdoc.cgi

    CHAIRMAN BARTON. I understand that. It looks like my time is expired, so I want to ask one more question. Dr. North, do you dispute the conclusions or the methodology of Dr. Wegman’s report?
    DR. NORTH. No, we don’t. We don’t disagree with their criticism. In fact, pretty much the same thing is said in our report. But again, just because the claims are made, doesn’t mean they are false.

    MR. STEARNS. Okay. Dr. Cicerone, you are the President of the National Academy of Science. Dr. Wegman is an appointed member of the National Academy of Science Board of Mathematical Sciences and Their Application. He is chair of the NAS Committee on Applied and Theoretical Statistics, highly credentialed in math and statistics, wouldn’t you say? Shouldn’t we take his judgments on statistical matters very seriously, and don’t they carry significant weight? Would you say his judgment about statistical matters is important and that he has credibility based upon those credentials?
    DR. CICERONE. Yes.

  9. Steve McIntyre
    Posted Apr 7, 2007 at 6:47 AM | Permalink

    #8. I remember those questions as being particularly telling at the hearing and I’m glad that you’ve highlighted them. In the face of such stinging rebukes, the cheek of the Team is pretty amazing.

    Also in terms of “improved” methods, Mann’s PC1 and bristlecones have been used more in recent studies than ever before – it’s as though the Team has snubbed their noses at criticism and shown solidarity with Mann by using his PC1. Osborn and Briffa 2006 use both Mann’s PC1 and a separate foxtail index in a very small subset – these are 2 of the most HS. HEgerl et al 2006 used both Mann’s PC1 and a foxtail index. Juckes used Mann’s PC methods and even experimented as to the effect of using different bias periods. Rutherford et al 2005 bodily used the MBH98 network, bad PCs and all. So they seem to have learned nothing from the HS episode.

  10. bender
    Posted Apr 7, 2007 at 7:17 AM | Permalink

    Re #8

    Largescale temperature reconstructions should always be viewed as having a “murky” early period and a later period of relative clarity.

    David H, you can’t even grant that, because the dendros do not understand at all the 20th c. “divergence problem”. No clarity whatsoever at this point.

  11. Stan Palmer
    Posted Apr 7, 2007 at 7:57 AM | Permalink

    re 9

    Re 8 and indirectly 3

    As a lurker, I have been reading the several comments on this board about “science” and especially the several recent comments about the “rejection of science” or the “rejection of consensus science”. The Wikipedai entry about the philosopher of science Paul Feyerabend describes his view on how scientific theories come to be accepted

    According to Feyerabend, new theories came to be accepted not because of their accord with scientific method, but because their supporters made use of any trick ‘€” rational, rhetorical or ribald ‘€” in order to advance their cause.

    It seems that Feyerabend’s insights are quite apposite for AGW science as well as for science in general

  12. Joel McDade
    Posted Apr 7, 2007 at 8:49 AM | Permalink

    I didn’t know that Steve was retired, that he is an engineer, or that he is from “Woola Woola.” 🙂

  13. Nicholas
    Posted Apr 7, 2007 at 9:31 AM | Permalink

    Perhaps he meant Wagga Wagga. Never heard of a town called Woola Woola and Google doesn’t seem to find anything relevant.

    I very much doubt Steve sent any “angry e-mails”. He is polite, but insistent, in my experience. The only person getting angry here is Hughes, because someone has the temerity to ask him to back up his claims with data. Sheesh, you get the impression listening to these people that they don’t understand that this sort of thing is the heart of science.

  14. Paul Linsay
    Posted Apr 7, 2007 at 9:32 AM | Permalink

    #11, from the same Wikipedia article:

    Feyerabend was critical of any guideline that aimed to judge the quality of scientific theories by comparing them to known facts.

    Postmodernism at it’s finest. He would be 100% comfortable with AGW, no grounding in reality needed!

  15. bernie
    Posted Apr 7, 2007 at 9:57 AM | Permalink

    I would be cautious attributing to Feyerabend such a grand grand conspiratorial pronouncement: There is clearly some degreee of “social construction” of all scientific theories through the characters or mileu. Certainly we are seeing more social construction of the science associated with AGW than has been visible within atmospheric sciences previoulsy. I take the lesson from Feyerabend to be that for a new socially important scientific viewpoint to prevail, widely accepted data and widely accepted interpretations of the data are necessary but not sufficent conditions: There will have to be the mobilizing of social, political and economic forces as well. (Not to mention a few mavericks like Steve and Ross, viz “characters”.)

    The NAS report is an interesting case in just this interplay of science, the politics of science and pure politics. My reading of the report tallies with #8 and many others on this site. It was a scientific slap down. MBH appear to be in denial – (see Feyerabend point above!)

    #7 re #3: DaleC, nice job: I love the data. (Even Popper and Wittgenstein could agree on this falsification.) Perhaps the entire interview was 11 minutes, and JMS was using a rhetorical flourish!!!

  16. bender
    Posted Apr 7, 2007 at 10:16 AM | Permalink

    At minute 13:40 Hughes distances himself from Bradley & Mann.

  17. bender
    Posted Apr 7, 2007 at 10:22 AM | Permalink

    At 19:48 Hughes distances himself from IPCC.

  18. bender
    Posted Apr 7, 2007 at 10:33 AM | Permalink

    Re #3
    JMS: “Hockey stick” is in the title of the work. It’s in the abstract. It’s in the first audio sentence. It dominates 50% of the interview.
    And the early part that does not discuss the hockey stick per se is merely an intro that sets up the discussion about the HS. In other words, the subject IS the HS. And Hughes spends a good part of that intro, I might add, describing the “extraordinary” uptick that we now know is one half of the rather serious divergence problem.

    What are you playing at, trying to spin this otherwise? Get thee to a nunnery.

  19. bender
    Posted Apr 7, 2007 at 10:43 AM | Permalink

    In this interview Hughes outlines the exact model put forth in #4 (I forgot to mention: P=Precip, T=Temp, C=Carbon, N=Nitrogen). The nonlinearity, the multivariate climate, it’s all there (except the interaction terms).

    So it is fair to say that there is nothing here the dendros don’t already know or believe. So tell me, dear dendros, where is the paper entitled:“The effect of model mis-specification error on millenial-scale temperature reconstructions”?
    That such a paper has not been written (or published) is shocking.

    Comments, Dr Wilson?

  20. KevinUK
    Posted Apr 7, 2007 at 11:14 AM | Permalink

    Just listened to the audio link.

    For those who missed it Hughes says at one point “We are still standing”. The “we” of course being the Hockey Team. I laughed so much when I heard this that I almost fell off my seat. And according to Robyn Williams the interviewer the NAS Panel report ‘endorsed’ the HS? Since when can you spin the word ‘plausible’ to mean endorsement?

    #18 bender, I totally agree with you this entire interview was about the HS not just 50% of it.


  21. Steve McIntyre
    Posted Apr 7, 2007 at 11:22 AM | Permalink

    #4. bender, this formulation is obviously complicated enough, but then you have positive and negative responders, for which Martin Wilmking says there are no obvious local effects. Geological substrate also matters – there’s a beautiful demarcation between sandstone and dolomite marked by the presence/absnece of bristlecones and big sagebrush respectively.

  22. Steve McIntyre
    Posted Apr 7, 2007 at 11:43 AM | Permalink

    Hughes said:

    there was this amazingly open system for people commenting on the earlier drafts, and thousands of people were asked to comment and every one of those comments had to be answered on the record by the authors of the drafts

    I wonder where that record is. I requested a copy of the Comments on the First-Order Draft on chapter 6, which I was entitled, and after some TSU deliberation, duly received in snail-form (hard-copy).

  23. bender
    Posted Apr 7, 2007 at 12:29 PM | Permalink

    amazingly open system for people commenting on the earlier drafts

    “amazingly open” (but not to the public)

    every one of those comments had to be answered on the record

    the *private* record (not the *public* record)

    It’s all in the semantics. Ask Chomsky.

  24. bender
    Posted Apr 7, 2007 at 12:55 PM | Permalink

    Re #21
    1. I am guessing the +/- responders actually fit right into the model.
    2. What about the idea that the + vs – responders are actually late vs early responders?
    (See #84 here:

  25. per
    Posted Apr 7, 2007 at 1:18 PM | Permalink

    i have some sympathy with JMS’ comments; i thought that comparatively little of the interview concerned the controversy of the HS; but then, i didn’t count 🙂

    some little gems in there; some quite waspish comments about michael mann, alluding perhaps to the high profile advocacy that he indulges in.

    There is also perhaps quite a hint of hughes perspective. He really is just interested in these bristlecone pines, and almost baffled that someone takes an interest in their Nature paper, MBH’98. It is just part of his enormous corpus of work, and no different from the rest of it. It almost seems like he just provided the data, and the consequences are nothing to do with him. The specific methodology and claims, that bristlecone pines are a temperature proxy, and the claim about temperature for the last 600 years; you can see he just doesn’t want to engage.

    As SM points out, when you look at the detail, Hughes is specifically saying that they are not temperature proxies, so it is just bizarre. However, at least he has a reasonable response that you have to engage with scientific criticism, and move on…

  26. bernie
    Posted Apr 7, 2007 at 2:36 PM | Permalink

    Can any of our antipodal cousins let me know who Robyn Williams is? Is he as misonformed as he appears to be or is he deliberately rewriting the record?

  27. Posted Apr 7, 2007 at 3:02 PM | Permalink

    Re 26, The Science Show web site and RW bio

  28. Steve McIntyre
    Posted Apr 7, 2007 at 3:16 PM | Permalink

    #25. per, the difficulty is that the Team’s positions are here, as elsewhere, mutually inconsistent.

  29. Ken Fritsch
    Posted Apr 7, 2007 at 3:28 PM | Permalink

    When Hughes says:

    Likewise with temperature, you can usually do a better job with tree rings of nailing down the cooler years than the warmer ones.

    is he attempting to explain the missing MWP in some of these dendrochronologies? Or is his remark confined to higher frequency responses?

  30. Alan Woods
    Posted Apr 7, 2007 at 3:54 PM | Permalink

    Robyn Williams has decided to take the Tim Flannery approach to climate science. Recently he asserted that a 100 metres (yes, 100 metres!) rise in sea levels was possible in the next 100 years.

  31. Steve McIntyre
    Posted Apr 7, 2007 at 4:05 PM | Permalink

    #29. High-frequency. That’s not a point that I would disagree with – indeed,I’ve said the same thing recently e.g. on NAturally Orthogonal.

  32. per
    Posted Apr 7, 2007 at 4:18 PM | Permalink

    #28. I am not lauding Hughes, by any means. I used the word “bizarre”.

    I note that in your coverage of MBH, we have seen comparatively little public comment from Hughes – certainly compared to Mann.

    I also get a distinct feeling from that interview that Hughes may feel himself to be a little remote from MBH’98; he certainly wasn’t rushing to justify the bristlecones as temperature proxies, and much of what he said made plain that the bristlecones were not temperature proxies; which brings with it the logic that bristlecones should not be used as temperature proxies 🙂

    He also appeared almost naive about the consequences of his work appearing as a centrepiece of the IPCC TAR. The idea that they were picked on because they had produced Figure 1b conspicuously fails to address the numerous demonstrable defects, like they published such a diabolically awful materials and methods section, etc.

    For my part, I have strong views about authors taking responsibility for material that is published with their name on it; so this is no apology for Hughes.


  33. Steve McIntyre
    Posted Apr 7, 2007 at 4:29 PM | Permalink

    per, Hughes is not exactly a shrinking violet in this. Hughes and Diaz 1994 stands at the head of the anti-MWP movement. The MBH99 press release included a Hughes quote about the MWP.

    Hughes and Diaz 1994 is BTW a horrendous study that I’ve never commented on here in detail. Even Esper said in his review of the IPCC 4AR First Draft that Hughes and Diaz 1994 should not be cited by IPCC 4AR. Let’s see whether it is.

    Also while I’ve been doing this recent survey of North American upper treeline studies, I noticed a really strange and interesting connection to the deletion of sites said to be used (listed in the MBH Corrigendum.) As someone who followed the early stages of this, you may like the point which I’ll try to get to this week.

  34. bender
    Posted Apr 7, 2007 at 4:38 PM | Permalink

    Ken, Hughes is referring here to the nonlinearity. i.e. As a factor becomes more luxuriant (less limiting) the response to an increase in it weakens. This is just the upside of the parabola, the saturating response. This, of course, has implications for inferences during the MWP and other; however the dendros never ever go so far as to specifically spell it out for us. Notice Hughes nonlinearity does not go so far as to include a downside to the parabola. The response saturates/plateaus, end of story. No trees stagnating during the “megadroughts”. No speculation about what that might mean to a reconstruction.

  35. Posted Apr 7, 2007 at 11:25 PM | Permalink

    Remember when you are dissecting the entrails of what Hughes says and speculating on this or that nuance, that the ABC Science Show is not just for dendro & statistical experts.

  36. bender
    Posted Apr 8, 2007 at 8:51 AM | Permalink

    Re #35 Of course. The last half of #34 (“Hughes nonlinearity”) was referring to the dendro literature, not the interview.
    The interview itself was very good, I thought. (Better than what I could do myself.) But that’s not the issue. The deficient specialist literature is the issue. See #19.

  37. Jim Edwards
    Posted Apr 9, 2007 at 7:27 AM | Permalink

    Does this mean Dr. Hughes doesn’t believe in the theory of “teleconnections” ?

    …we decided early on that we were going to use as many lines of evidence that met certain quality control and certain characteristics. Basically, it had to have at least once a year record and it had to be good evidence that it was related in some way to local climate and so on.

  38. bender
    Posted Apr 9, 2007 at 8:25 AM | Permalink

    Re: Local response vs teleconnection
    These are not mutually exclusive alternatives. Trees MUST respond to local climate. In the absence of knowledge about the local climate, it is possible – if climate in locale X is correlated with that in locale y (through teleconnections) – that trees in region X will appear to be responding to climate in region Y. I suspect this would be Hughes presumption as well. Be careful of creating false dichotomies, and then trying to associate different people with different contradictory beliefs. You’ll start seeing things that are not there.

  39. Steve Sadlov
    Posted Apr 9, 2007 at 9:56 AM | Permalink

    RE: These trees are some hundreds of kilometres downwind of LA. If fog or smog can get to the Grand Canyon from the LA area it should be able to get to eastern California, too. So we haven’t completely ruled that out either.

    Smog from the SF Bay Area is well known to blow through the Altamont and Pacheco Passes, and end up in the San Joaquin Valley. From there, the fierce winds which sometimes blow through the Tehachapi Pass, east of Bakersfield (witness all the power generation windmills there) can actually bring some of it into the Northern Mojave and Owens Valley.

  40. Steve Sadlov
    Posted Apr 9, 2007 at 10:00 AM | Permalink

    RE: Having stood downwind of the Corona/Norco area on a damp evening, I can personally attest to elevated airborne nitrogen levels in Southern California.

    Most of that smog follows I-10, out past Cabezon, then into the Salton Trough. From there, some of it can then indeed reach out into the Grand Canyon and 4-corners area. Although, truthfully, when Arizonans try to blame SoCal for their air pollution issues, its a bit dinengenous. Look at Phoenix and look at the coal power plants. That’s where most of the Grand Canyon and 4-corners smog is actually from. The southern Rockies trap it all and the prevailing winds, which have a southerly component during most of the year, move it in a net north direction.

  41. Jim Edwards
    Posted Apr 9, 2007 at 10:52 AM | Permalink

    #38: Bender

    Good point. I didn’t create a dichotomy, however. [false or otherwise]
    I could have been clearer had I written more to contrast Hughes’ statement with those who seem to believe it’s possible for a grove of trees to be simultaneously a good global proxy and poor local proxy. This is what I meant by “teleconnections”. The point is, he doesn’t seem to be pushing the same view as some others do. He also seems to be saying that Mann also agreed that trees couldn’t be ‘teleconnected’ without being tuned into the local environment.

  42. bender
    Posted Apr 9, 2007 at 11:20 AM | Permalink

    Only an idiot thinks a grove of trees can be a poor local proxy yet a good global proxy. There are no idiots in science. They get weeded out early on.

  43. jae
    Posted Apr 9, 2007 at 4:49 PM | Permalink

    There are no idiots in science. They get weeded out early on.

    Are you sure?

  44. Ian Castles
    Posted Apr 9, 2007 at 8:14 PM | Permalink

    In confirmation of Steve McIntyre’s comment in #33 that Hughes is not a “shrinking violet” in the anti-MWP movement, the following is from a letter sent to the Editor of USA today on 29 October 2003, signed by Michael Mann, Raymond Bradley, Keith Briffa, Philip Jones and Malcolm Hughes and published on Stephen Schneider’s website:

    “We … wish to inform your readers that late-20th century warming is unprecedented not only in the past six centuries (as shown by Mann and colleagues in 1998), but at least the past two millennia (see attached graph, which we request that you publish) [Graph reprinted from Mann et al, 2003,”On Past Temperatures and Anomalous Late 20th Century Warmth”, “Eos”, 84:256-258].

    “… Unfortunately, the data on which the McIntyre & McKitrick analysis was based, which was forwarded to them by a colleague of Mann’s at the request of McIntyre & McKitrick, was inadvertently scrambled during tabulating for transmission to them, rendering the data for earlier centuries useless. Had McIntyre and McKitrick directly downloaded the data from the publicly available website which they were encouraged to do by Mann’s team this would not have occurred,

    McIntyre & McKitrick then applied a flawed methodology to the scrambled data, and reached mistaken conclusions wildly at odds with many peer-reviewed scientific studies.

    Had the researchers themselves been experts, had they sought comments in advance from experts in the field (including Dr. Mann), had they submitted their paper to a reputable scientific journal all of which are standard procedures in scientific publication, the flaws would have been discovered. Instead, the authors, who are not scientists – one is a mining executive, the other an economist – published their article in a social science magazine that does not apply widely accepted standards of review by scientific experts…”

  45. Jim Edwards
    Posted Apr 10, 2007 at 1:38 AM | Permalink

    #42 bender

    Let’s agree there are very few idiots in science; I met a doctoral student in molecular biology when I was at U of Calif. who was actually surprised to learn there are microscopic organisms in the Pacific Ocean.

    But if what you say is true, why is it that some paleoclimatologists seem to be pushing the use of certain BCP as global temp proxies when it has been reported that the ‘blade’ uptick in late 20th cent growth is not reflected in the local instrumental record ? Are you saying they are idiots or not scientists ?

  46. Boris
    Posted Apr 13, 2007 at 3:21 PM | Permalink

    They try to soften the blow by saying Mann’s conclusions are “plausible” which some people, who have not looked the word up, think is a point in Mann’s favor. It is not. In most dictionaries an element of deception is implied.

    Word parsing at its finest. I’m sure the NAS were going for the rarely used “deceptive” definition. Bravo.

  47. MarkW
    Posted Jun 7, 2007 at 5:04 AM | Permalink


    You really need to look up what words mean.
    Saying that something is plausible, is only one step removed from saying that it is unlikely. It is the lowest possible form of agreement.

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