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The Montford Delusion

Filed under: — group @ 22 July 2010

Guest commentary by Tamino

Update: Another review of the book has been published by Alistair McIntosh in the Scottish Review of Books (scroll down about 25% through the page to find McIintosh’s review)

Update #2 (8/19/10): The Guardian has now weighed in as well.

If you don’t know much about climate science, or about the details of the controversy over the “hockey stick,” then A. W. Montford’s book The Hockey Stick Illusion: Climategate and the Corruption of Science might persuade you that not only the hockey stick, but all of modern climate science, is a fraud perpetrated by a massive conspiracy of climate scientists and politicians, in order to guarantee an unending supply of research funding and political power. That idea gets planted early, in the 6th paragraph of chapter 1.

The chief focus is the original hockey stick, a reconstruction of past temperature for the northern hemisphere covering the last 600 years by Mike Mann, Ray Bradley, and Malcolm Hughes (1998, Nature, 392, 779, doi:10.1038/33859, available here), hereafter called “MBH98” (the reconstruction was later extended back to a thousand years by Mann et al, 1999, or “MBH99” ). The reconstruction was based on proxy data, most of which are not direct temperature measurements but may be indicative of temperature. To piece together past temperature, MBH98 estimated the relationships between the proxies and observed temperatures in the 20th century, checked the validity of the relationships using observed temperatures in the latter half of the 19th century, then used the relationships to estimate temperatures as far back as 1400. The reconstruction all the way back to the year 1400 used 22 proxy data series, although some of the 22 were combinations of larger numbers of proxy series by a method known as “principal components analysis” (hereafter called “PCA”–see here). For later centuries, even more proxy series were used. The result was that temperatures had risen rapidly in the 20th century compared to the preceding 5 centuries. The sharp “blade” of 20th-century rise compared to the flat “handle” of the 15-19th centuries was reminiscent of a “hockey stick” — giving rise to the name describing temperature history.

But if you do know something about climate science and the politically motivated controversy around it, you might be able to see that reality is the opposite of the way Montford paints it. In fact Montford goes so far over the top that if you’re a knowledgeable and thoughtful reader, it eventually dawns on you that the real goal of those whose story Montford tells is not to understand past climate, it’s to destroy the hockey stick by any means necessary.

Montford’s hero is Steve McIntyre, portrayed as a tireless, selfless, unimpeachable seeker of truth whose only character flaw is that he’s just too polite. McIntyre, so the story goes, is looking for answers from only the purest motives but uncovers a web of deceit designed to affirm foregone conclusions whether they’re so or not — that humankind is creating dangerous climate change, the likes of which hasn’t been seen for at least a thousand or two years. McIntyre and his collaborator Ross McKitrick made it their mission to get rid of anything resembling a hockey stick in the MBH98 (and any other) reconstruction of past temperature.

Principal Components

For instance: one of the proxy series used as far back as the year 1400 was NOAMERPC1, the 1st “principal component” (PC1) used to represent patterns in a series of 70 tree-ring data sets from North America; this proxy series strongly resembles a hockey stick. McIntyre & McKitrick (hereafter called “MM”) claimed that the PCA used by MBH98 wasn’t valid because they had used a different “centering” convention than is customary. It’s customary to subtract the average value from each data series as the first step of computing PCA, but MBH98 had subtracted the average value during the 20th century. When MM applied PCA to the North American tree-ring series but centered the data in the usual way, then retained 2 PC series just as MBH98 had, lo and behold — the hockey-stick-shaped PC wasn’t among them! One hockey stick gone.

Or so they claimed. In fact the hockey-stick shaped PC was still there, but it was no longer the strongest PC (PC1), it was now only 4th-strongest (PC4). This raises the question, how many PCs should be included from such an analysis? MBH98 had originally included two PC series from this analysis because that’s the number indicated by a standard “selection rule” for PC analysis (read about it here).

MM used the standard centering convention, but applied no selection rule — they just imitated MBH98 by including 2 PC series, and since the hockey stick wasn’t one of those 2, that was good enough for them. But applying the standard selection rules to the PCA analysis of MM indicates that you should include five PC series, and the hockey-stick shaped PC is among them (at #4). Whether you use the MBH98 non-standard centering, or standard centering, the hockey-stick shaped PC must still be included in the analysis.

It was also pointed out (by Peter Huybers) that MM hadn’t applied “standard” PCA either. They used a standard centering but hadn’t normalized the data series. The 2 PC series that were #1 and #2 in the analysis of MBH98 became #2 and #1 with normalized PCA, and both should unquestionably be included by standard selection rules. Again, whether you use MBH non-standard centering, MM standard centering without normalization, or fully “standard” centering and normalization, the hockey-stick shaped PC must still be included in the analysis.

In reply, MM complained that the MBH98 PC1 (the hockey-stick shaped one) wasn’t PC1 in the completely standard analysis, that normalization wasn’t required for the analysis, and that “Preisendorfer’s rule N” (the selection rule used by MBH98) wasn’t the “industry standard” MBH claimed it to be. Montford even goes so far as to rattle off a list of potential selection rules referred to in the scientific literature, to give the impression that the MBH98 choice isn’t “automatic,” but the salient point which emerges from such a list is that MM never used any selection rules — at least, none that are published in the literature.

The truth is that whichever version of PCA you use, the hockey-stick shaped PC is one of the statistically significant patterns. There’s a reason for that: the hockey-stick shaped pattern is in the data, and it’s not just noise it’s signal. Montford’s book makes it obvious that MM actually do have a selection rule of their own devising: if it looks like a hockey stick, get rid of it.

The PCA dispute is a prime example of a recurring McIntyre/Montford theme: that the hockey stick depends critically on some element or factor, and when that’s taken away the whole structure collapses. The implication that the hockey stick depends on the centering convention used in the MBH98 PCA analysis makes a very persuasive “Aha — gotcha!” argument. Too bad it’s just not true.

Different, yes. Completely, no.

As another example, Montford makes the claim that if you eliminate just two of the proxies used for the MBH98 reconstruction since 1400, the Stahle and NOAMER PC1 series, “you got a completely different result — the Medieval Warm Period magically reappeared and suddenly the modern warming didn’t look quite so frightening.” That argument is sure to sell to those who haven’t done so. But I have. I computed my own reconstructions by multiple regression, first using all 22 proxy series in the original MBH98 analysis, then excluding the Stahle and NOAMER PC1 series. Here’s the result with all 22 proxies (the thick line is a 10-year moving average):

Here it is with just 20 proxies:

Finally, here are the 10-year moving average for both cases, and for the instrumental record:

Certainly the result is different — how could it not be, using different data? — but calling it “completely different” is just plain wrong. Yes, the pre-20th century is warmer with the 15th century a wee bit warmer still — but again, how could it not be when eliminating two hand-picked proxy series for the sole purpose of denying the unprecedented nature of modern warming? Yet even allowing this cherry-picking of proxies is still not enough to accomplish McIntyre’s purpose; preceding centuries still don’t come close to the late-20th century warming. In spite of Montford’s claims, it’s still a hockey stick.

Beyond Reason

Another of McIntyre’s targets was the Gaspe series, referred to in the MBH98 data as “treeline-11.” It just might be the most hockey-stick shaped proxy of all. This particular series doesn’t extend all the way back to the year 1400, it doesn’t start until 1404, so MBH98 had extended the series back four years by persistence — taking the earliest value and repeating it for the preceding four years. This is not at all an unusual practice, and — let’s face facts folks — extending 4 years out of a nearly 600-year record on one out of 22 proxies isn’t going to change things much. But McIntyre objected that the entire Gaspe series had to be eliminated because it didn’t extend all the way back to 1400. This argument is downright ludicrous — what it really tells us is that McIntyre & McKitrick are less interested in reconstructing past temperature than in killing anything that looks like a hockey stick.

McIntyre also objected that other series had been filled in by persistence, not on the early end but on the late end, to bring them up to the year 1980 (the last year of the MBH98 reconstruction). Again, this is not a reasonable argument. Mann responded by simply computing the reconstruction you get if you start at 1404 and end at 1972 so you don’t have to do any infilling at all. The result: a hockey stick.

Again, we have another example of Montford implying that some single element is both faulty and crucial. Without nonstandard PCA the hockey stick falls apart! Without the Stahle and NOAMER PC1 data series the hockey stick falls apart! Without the Gaspe series the hockey stick falls apart! Without bristlecone pine tree rings the hockey stick falls apart! It’s all very persuasive, especially to the conspiracy-minded, but the truth is that the hockey stick depends on none of these elements. You get a hockey stick with standard PCA, in fact you get a hockey stick using no PCA at all. Remove the NOAMER PC1 and Stahle series, you’re left with a hockey stick. Remove the Gaspe series, it’s still a hockey stick.

As a great deal of other research has shown, you can even reconstruct past temperature without bristlecone pine tree rings, or without any tree ring data at all, resulting in: a hockey stick. It also shows, consistently, that nobody is trying to “get rid of the medieval warm period” or “flatten out the little ice age” since those are features of all reconstructions of the last 1000 to 2000 years. What paleoclimate researchers are trying to do is make objective estimates of how warm and how cold those past centuries were. The consistent answer is, not as warm as the last century and not nearly as warm as right now.

The hockey stick is so thoroughly imprinted on the actual data that what’s truly impressive is how many things you have to get rid of to eliminate it. There’s a scientific term for results which are so strong and so resistant to changes in data and methods: robust.

Cynical Indeed

Montford doesn’t just criticize hockey-stick shaped proxies, he bends over backwards to level every criticism conceivable. For instance, one of the proxy series was estimated summer temperature in central England taken from an earlier study by Bradley and Jones (1993, the Holocene, 3, 367-376). It’s true that a better choice for central England would have been the central England temperature time series (CETR), which is an instrumental record covering the full year rather than just summertime. The CETR also shows a stronger hockey-stick shape than the central England series used by MBH98, in part because it includes earlier data (from the late 17th century) than the Bradley and Jones dataset. Yet Montford sees fit to criticize their choice, saying “Cynical observers might, however, have noticed that the late seventeenth century numbers for CETR were distinctly cold, so the effect of this truncation may well have been to flatten out the little ice age.”

In effect, even when MBH98 used data which weakens the difference between modern warmth and preceding centuries, they’re criticized for it. Cynical indeed.


The willingness of Montford and McIntyre to level any criticism which might discredit the hockey stick just might reach is zenith in a criticism which Montford repeats, but is so nonsensical that one can hardly resist the proverbial “face-palm.” Montford more than once complains that hockey-stick shaped proxies dominate climate reconstructions — unfairly, he implies — because they correlate well to temperature.



Criticism of MBH98 isn’t restricted to claims of incorrect data and analysis, Montford and McIntyre also see deliberate deception everywhere they look. This is almost comically illustrated by Montford’s comments about an email from Malcolm Hughes to Mike Mann (emphasis added by Montford):

Mike — the only one of the new S.American chronologies I just sent you that already appears in the ITRDB sets you already have is [ARGE030]. You should remove this from the two ITRDB data sets, as the new version should be different (and better for our purposes).

Here’s what Montford has to say:

It was possible that there was an innocent explanation for the use of the expression “better for our purposes”, but McIntyre can hardly be blamed for wondering exactly what “purposes” the Hockey Stick authors were pursuing. A cynic might be concerned that the phrase actually had something to do with “getting rid of the Medieval Warm Period”. And if Hughes meant “more reliable”, why hadn’t he just said so?

This is nothing more than quote-mining, in order to interpret an entirely innocent turn of phrase in the most nefarious way possible. It says a great deal more about the motives and honesty of Montford and McIntyre, than about Mann, Bradley, and Hughes. The idea that MM’s so-called “correction” of MBH98 “restored the MWP” constitutes a particularly popular meme in contrarian circles, despite the fact that it is quite self-evidently nonsense: MBH98 only went back to AD 1400, while the MWP, by nearly all definitions found in the professional literature, ended at least a century earlier! Such internal contradictions in logic appear to be no impediment, however, to Montford and his ilk.

Conspiracies Everywhere

Montford also goes to great lengths to accuse a host of researchers, bloggers, and others of attempting to suppress the truth and issue personal attacks on McIntyre. The “enemies list” includes RealClimate itself, claimed to be a politically motivated mouthpiece for “Environmental Media Services,” described as a “pivotal organization in the green movement” run by David Fenton, called “one of the most influential PR people of the 20th century.” Also implicated are William Connolley for criticizing McIntyre on sci.environment and James Annan for criticizing McIntyre and McKitrick. In a telling episode of conspiracy theorizing, we are told that their “ideas had been picked up and propagated across the left-wing blogosphere.” Further conspirators, we are informed, include Brad DeLong and Tim Lambert. And of course one mustn’t omit the principal voice of RealClimate, Gavin Schmidt.

Perhaps I should feel personally honored to be included on Montford’s list of co-conspirators, because yours truly is also mentioned. According to Montford’s typical sloppy research I have styled myself as “Mann’s Bulldog.” I’ve never done so, although I find such an appellation flattering; I just hope Jim Hansen doesn’t feel slighted by the mistaken reference.

The conspiracy doesn’t end with the hockey team, climate researchers, and bloggers. It includes the editorial staff of any journal which didn’t bend over to accommodate McIntyre, including Nature and GRL which are accused of interfering with, delaying, and obstructing McIntyre’s publications.

Spy Story

The book concludes with speculation about the underhanded meaning of the emails stolen from the Climate Research Unit (CRU) in the U.K. It’s really just the same quote-mining and misinterpretation we’ve heard from many quarters of the so-called “skeptics.” Although the book came out very shortly after the CRU hack, with hardly sufficient time to investigate the truth, the temptation to use the emails for propaganda purposes was irresistible. Montford indulges in every damning speculation he can get his hands on.

Since that time, investigation has been conducted, both into the conduct of the researchers at CRU (especially Phil Jones) and Mike Mann (the leader of the “hockey team”). Certainly some unkind words were said in private emails, but the result of both investigations is clear: climate researchers have been cleared of any wrongdoing in their research and scientific conduct. Thank goodness some of those who bought in to the false accusations, like Andy Revkin and George Monbiot, have seen fit actually to apologize for doing so. Perhaps they realize that one can’t get at the truth simply by reading people’s private emails.

Montford certainly spins a tale of suspense, conflict, and lively action, intertwining conspiracy and covert skullduggery, politics and big money, into a narrative worthy of the best spy thrillers. I’m not qualified to compare Montford’s writing skill to that of such a widely-read author as, say, Michael Crichton, but I do know they share this in common: they’re both skilled fiction writers.

The only corruption of science in the “hockey stick” is in the minds of McIntyre and Montford. They were looking for corruption, and they found it. Someone looking for actual science would have found it as well.

581 Responses to “The Montford Delusion”

  1. 201
    Peter Webster says:

    Thanks Gavin,

    But I think that we are approaching new depths of interaction. This saddens me. I have always thought that realclimate was a bit of a “shining city on the hill’. That may be a bit Reaganesque but you may get the idea. Whether you believe it or not, many contrary points require detailed and dull reponses. This may be tedious but it is better than two camps throwing rocks at each other. I worry that we may not have the luxuries we have had in the past come November. So I think that we have to make sure that those enquiring comments may not be coming from enemies but from those who have serious questions and who may not be too far from majority opinion.

    For what that is worth.


    [Response: If I never write another word about MBH I will be a happy camper. There have been patient and dull responses to all of these things in the literature that Judith hasn’t read. And there will be more in responses to lawsuits, petitions, inquiries and the like. But people who have loudly insisted that we address ‘issues’ come across as a little confused if they complain when we do. Either you want our opinion, or you don’t. Now you have it. For what it’s worth. – gavin]

  2. 202
    chek says:

    Gavin: ” If I had a choice I wouldn’t expend a single further electron on this subject,”

    I fully understand how frustrating this must be Gavin and thank you for sticking with it, because exposing the threadbare contentions of the various socks at play in this thread, and the pseudo-respectably that has been bestowed on them by real scientist/mascot Dr. Curry, (who has so far been shown herself to be equally bereft of any relevant point) is going a long way towards exposing the “white collar” acceptance of what is called ‘climategate’. The points you and Tamino are making as open and direct inline responses are exactly what needs to be made crystal clear to the Revkins and the Monbiots of this world.

    I suspect that more than a few of Montford’s and McIntyre’s readership and cheersquads have never been given such clarity and insight (at least those whose heads it hasn’t all zoomed over) into what they thought they’d signed up to before.

  3. 203
    Hank Roberts says:

    “‘Have you noticed that a new kind of scientific expert has been born? It is the non-climate scientist “climate scientist’….”

  4. 204
    Neal J. King says:

    Is the Judith Curry that has been posting on this topic actually the Judith Curry that is chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology?

    It’s really hard to believe that someone in that position thinks that regurgitating conclusions from a book constitutes a “review”. The way I think about it, the term “review” implies that some critical intelligence has been applied to evaluate the significance and import of the book; which she states that she has NOT done. A “review” is not the same as a “summary”.

    This entire sequence of postings reminds me of the zombie movie, “Night of the Living Dead”: Scientists are falling asleep and waking up as apologists for denialist blogs.

    For shame, Judith! For shame!

  5. 205
    Eli Rabett says:

    To Peter Webster,

    To repeat, Judith Curry first states that Tamino’s review contains (IN HER OWN WORDS) “numerous factual errors and misrepresentations, failure to address many of the main points of the book”.

    Now some, not Eli, he hastens to add, would think that an eminent scientist, expert in closely related matters, making such an accusation would have an excellent grasp of the background material.

    And indeed, when challenged Prof. Curry provides a list of many points, which most, not Eli, he hastens to add, would think were her views of what these factual errors are. Indeed, she characterized her actions by “so I am taking a few moments to clarify the weaknesses in Tamino’s review”

    Yet, when challenged, Prof. Curry demurrs that none of these reflect her personal opinion but were rather points that Montford made in his book, on which, of course, she has no opinion, but since gavin and tamino chose to rag on the rich dish she put on their plate, why, of course, Montford must be right.

    And, you, of course, chime in saying that Gavin was mean.

    Sorry Peter, but that is a bit much. There comes a point at which the dissembling is no longer amusing, and Prof. Curry is rapidly approaching that point. Were Eli Gavin, which he is not, both hasten to add, he would not have withdrawn a word.

  6. 206
    David B. Benson says:

    At this point the comments begin to remind me of the Japanese chef who comes to slice and dice at your table. What’s the style called again?

  7. 207
    Doug Bostrom says:

    [edit – it is she. Further speculation is OT]

    Sorry, and sorry to hear it. :-(

  8. 208
    Jen says:

    Heavens. As a Ga Tech grad from EAS (years before Judith Curry was there), I am embarrassed. This thread is simply distressing. I know Judy is an intelligent scientist – so this repetition of misinformation is simply baffling. I suspect she needs time to cool off and then will hopefully take time to (re)read the papers and reports. Perhaps she can post a retraction in the near future and try to repair some of the damage? Facts are facts are facts, and a careful, quiet analysis beats rhetoric every time.

  9. 209
    Rick Brown says:

    Gavin, For what it’s worth, it was quite clear to me that your use of “bitching” was not in reference to Judith Curry.

  10. 210
    Ian Forrester says:

    There are many discussions on “tipping points” in climate science. I think we have just witnessed one. JC has been tipped into a moral and intellectual black hole.

  11. 211
    pete best says:

    This is a stunning peice. I thank the climate scientists here for replying to so many posts and giving such in depth answers. Its time the so called skeptics (although not scientifically skepical as all scientists are in order to be scientists) were taken down once and for all. They dont print through the scientific process, they just go to meetings, are given column inches and blog which is all bogus nonsense.

    Shame really about the credence given to some of the stuff listed here in black. The gree literature is thorough, referenced and very well put. No one can berate RC for not answering all comers who post with some knowledge, merit and intelligence themselves however misguided.

  12. 212
    turboblocke says:

    Judith Curry seems to have picked her side in the debate:

    see comment 28 by James G JamesG Says:
    June 22nd, 2010 at 5:13 am

    Well if you believe that the establishment is always correct then you may be happy to see this, which will be further confirmation of your herdlike tendency. If your experience though is of the harsh history that science largely progresses by maverick truth-seekers challenging the establishment (and on the way suffering many insults from them) then you are less impressed. Or is malaria really from bad air, are cauliflower ears really a sign of insanity, is the atom like a plum pudding and is the universe a steady state after all, etc, etc.

    Now when they compare the predictions of this compliant herd with actual reality and note that not once (so far) have any of them been proven correct with any theories that warming is other than benign or beneficial, then that’s real science, ie the comparison of hypothesis with real data. This effort is more like a show of hands of people being asked the question, “do you want to be among the winners or losers? choose wisely..because the winners get funded and the losers vilified”. I don’t think it’s a new low…it’s the same scenario that’s been played out many times throughout the inglorious history of various scientific establishments. We like to look back and laugh and say “how could they be so closed-minded, thank heaven we’ve moved on”. Except that we didn’t.

    I had seriously hoped that the idea that a consensus represented anything other than unimaginative groupthink had crashed and burned with the absolute failure of the academic economics establishment to predict this financial crash. Alas….

    And look how Curry reacts:
    Judith Curry Says:
    June 22nd, 2010 at 7:24 am

    JamesG #28 very well said!

  13. 213
    Steve Bloom says:

    I’m thinking of taking a page from “ThinkingScientist” and “Laws of Nature” and switching my handle to “Underlying Basis of Reality.” Consequently, all will be forced to give me the final word. :)

  14. 214
    Steve Metzler says:

    This turns out to be the most… interesting thread I have read on RC to date. Wherein Judith Curry is caught out on regurgitating denialist trope without bothering to even cursorily verify the veracity of the claims, and turns out to be nothing but a tone troll. For the record, I already formed this opinion several months back from her last drive-by here.

    I don’t expect this comment to make it through moderation. But it had to be said.

    If for some reason this comment doesn’t die an electronic death, I’d like to bolster the argument that the MBH98 proxy reconstruction isn’t the only one out there by reminding people of this article:

    Hey Ya! (mal)

    Funny how, except from the borehole one which finds an increase of +1 deg C in the last 500 yrs, all the other proxies mysteriously arrive at an anomaly of around +0.7 deg C. Must be a conspiracy, huh?

  15. 215
    Horatio Algeranon says:

    Judith Curry:

    First, Montford’s book clarifies three weaknesses in the paleoreconstructions, from MBH 98/99 through Mann et al 08. These include problems with tree rings, the centered PCA analysis, and the R2 issue…The centered PCA and R2 issues are much more straightforward…The centered PCA is bad statistics,”

    Is that really what Montford’s book claims, that “The centered PCA is bad statistics”?

    ..cuz Horatio thought that one of Steve McIntyre’s pet peeves was pretty much the opposite: that MBH98 had not used (standard) “centered PCA” but had instead used what McIntyre referred to as “non-centered PCA”.

    But now we learn from Montford (or from Curry’s interpretation of Montford?) that “centered PCA is bad statistics”?? (too??)

    Somebody better inform Ian Jolliffe and all the others who have made (standard) “centered PCA” their bread and butter, cuz they have undoubtedly wasted a lot of time (some their entire career!)

  16. 216
    David Horton says:

    I keep trying, really I do, to understand the apparent position of people like Curry. If she does come back on perhaps she could explain this. The constant reiteration of “the hockey stick is broken” or variations on that theme (as in Curry’s point 9 comment #168)- what, exactly, do you think that means? Does it mean that the temperature rise (and concomitant effects) of the last few decades are not astonishingly fast in the context of the last thousand years or so? Or does it mean that the rate and extent of change in the MWP (and its geographic distribution and timing) so exactly matches the recent change as to completely negate its significance? Either way, are you seriously suggesting that the rapid rise in CO2 levels in the last few decades are just pure coincidence? Or are you merely knit picking? Are you just saying that the handle of the hockey stick just has a bit of a kink in it and therefore shouldn’t be called a “hockey stick” but a “kinked hockey stick” and therefore the “hockey stick is broken”? I mean, that sounds silly to me, and I don’t think any serious scientist would play those sort of word games in the face of the growing environmental catastrophe that clearly awaits us if we continue to do nothing to rein in CO2 output. Would they?

  17. 217
    jo abbess says:


    Praise and thanks for a most helpful, robust post.

    As I was reading through it, I thought I could feel little ripples of anger waves radiating from it. You clearly described errors as errors, and you correctly identified unhelpful agendas and motivations, but you were not once nasty or mean. What a decent person you are, even when riled.

    That’s definitely what we need here – more righteous anger.

    I was talking with a Member of the UK’s Royal Statistical Society the other day, and our conversation foundered because he’d read and heard about the mythological “statistical problems” with the Hockey Stick analysis.

    He hadn’t checked the story out, but he’d heard and believed the malicious sceptical viewpoint before even looking at the data. A lie travels all the way around the globe before the truth can put its trousers on, or some such quotation.

    Where did he come across this erroneous narrative ? The print and online Media, of course. How shameful ! How typical ! How irritating ! The journalists are participating in mass “divide and rule”, causing ruction and watercooler wars everywhere, even amongst people who have proper educations.

  18. 218
    carrot eater says:

    Why are we still talking about this same paper? This is absurd.

    If we must discuss that paper, let’s put it in context of what’s happened since then. While all the other reconstructions are hockey-stick-like as well, they tend to have more variability along the stick. Including Mann’s own subsequent work. Particularly also Moberg, which emphasizes low-resolution proxies.

    Can somebody comment on the primary reasons for this difference in variability? Is it in the mathematical processing, or is it a result of using different kinds of proxies?

  19. 219
    jo abbess says:


    I have been reading some of your replies to Judith Curry and I have to say I’m pleased at how polite, calm and informational you are being, in the face of what appears to be extreme provocation.

    Despite vindication after vindication, and corroboration after corroboration of Michael Mann et al.s’ work, she appears to be unable to read a simple graph and accept the natural conclusions.

    I keep asking myself, is she actually a real person ? And if she is for real, is she for real ? I mean, does she really believe what she is saying ?

    If I had the chance to chat with Judith, I’d probably say something like “You’ve got to get some headspace for the blindingly obvious correlations and probabilities, follow the big ticket trends, and stop getting bogged down with spuriosities !”

  20. 220
    AIC says:

    OT, but related to #69 (and now the Lake Delhi Dam has failed) and similar heavy rainfall events…
    Is there enough historical weather information to establish whether we are experiencing an increase in these deluge/downpours? Could be an interesting paper…or maybe it has already been written.

  21. 221
    thingsbreak says:

    Those who are expressing shock and dismay that Judith Curry is uncritically repeating long-debunked talking points and disinformation haven’t been following her comments elsewhere in the blogosphere, e.g. Collide-A-Scape. It’s become an unfortunate and oft-repeated pattern:

    She regurgitates a claim made elsewhere by sources of dubious credibility without giving them even a cursory fact-check. She is subsequently shown refuting evidence and called out on it. She either ignores the criticism or claims that those rebutting the claims aren’t addressing the “real” issues, whichever they happen to be after the ones she raised initially are shot down. Rinse and repeat. She’s done this with claims by McIntyre, Pat Michaels, Montford to name a few.

    And lest anyone believes that she’s been unnecessarily and unfairly persecuted merely for disagreeing with RC, the IPCC, etc., it seems to me that the majority of criticism being directed her way is intended to help her gain some modicum of awareness of her own patterns of behavior. Her actions are about as diametrically opposed to skepticism as I can imagine, and it’s more than a little sad to witness.

  22. 222
    Andy says:

    Gavin/Eli/Tamino: thanks so much. Long, carefully thought out, and articulate discussions such as those found on Real Climate, Rabbett Run and Open Mind have allowed me to remain confident in the scientific basis of concerns over global warming and ocean acidification (well sometimes Eli mystifies me). I know this takes a lot of your time. My “away from work” time is essential and so you’re work is all the more impressive. Finally, I must say that seeing someone else using my dad’s favorite saying “Sxxx or get off the pot” really makes my day. In regards to Dr. Curry; I guess it was just gas after all.

  23. 223
    Hank Roberts says:

    I keep telling people, don’t think of it as a hockey stick.
    It looks much more like a scythe — with curves.

  24. 224
    Geoff Wexler says:

    Have I missed something?

    In physics, the choice of basis set is usually of little importance.It is just a matter of efficiency and saving machine time. If you know that your electrons are fairly free for example, it is sensible but not essential to start with a basis which includes that property as built in (e.g. augmented plane waves).

    [I am not 100% sure of what follows]

    The following is partly influenced by Tamino’s earlier article (hockey stick part 5) in Open Mind. But I no longer have the article so have to rely on memory and am taking it a bit further. So he might disagree.

    Isn’t it too weak to assert that non centred PCA gives almost the same results as centred? Isn’t it valid to have called it the natural choice? Wasn’t this demonstrated by the fact that that it converged faster than centred PCAs

    This could follow if the authors had good reason to predict that their data contained a hockey stick. Now the authors could have been wrong in their initial assumption, but if they had been, wouldn’t that have shown up as poor convergence, which was the opposite of what happened, excessively large error bars, or a substantially different output in the end? Since none of these things appear to have happened, the case for using non centered PCA’s was given a slight boost.

    One of the oft repeated criticisms * is that too little advice was taken from professional statisticians. Perhaps it should have been the other way around? This may turn out to be an interesting case study to be included in future statistics books? Instead, even after all this time, I still hear unsubstantiated allegations, undue reverence to statistical texts being cast in tablets of stone and slightly dodgy authority in an attempt to find something sinister.

    It is true that the proxy problem is not quite analagous to the condensed matter physics problem because it involves some quite tricky problems of removing noise and irrelevant variability. Perhaps there is an opportunity for some more research , not necessarily in the climate area?

    Sorry if all this has been said before.
    * The Oxburgh report echoed this advice, but it may have been because one of the authors had read Wegmann.

  25. 225
    dhogaza says:

    Jo Abbess asks:

    I keep asking myself, is she actually a real person ? And if she is for real, is she for real ? I mean, does she really believe what she is saying ?

    Yes, Judith Curry is very real.

    That’s why people are so upset with her and insist on holding her to a higher standard than your typical science-illiterate denialist such as Montford, whose book she apparently believes to be a more reliable source of information on climate science than the work and statements of her peers…

  26. 226
    Vendicar Decarian says:

    ” I know Judy is an intelligent scientist – so this repetition of misinformation is simply baffling. I suspect she needs time to cool off and then will hopefully take time to (re)read the papers and reports.” – 208

    There is a near universal lack of understanding and appreciation here for the nature of the “debate”.

    This is not a debate between rational scientists and some well meaning group of honest skeptics who use honest logic and honest reason to formulat honest arguments against the science.

    The motivation of the skeptics is entirely emotional. They are beyond reason, beyond rational thought, and have little concept of the scope and breadth of what is known or what is even possible.

    Their motivation is not truth, but to avoid change, using whatever means necessary.

    Change would mean that their world view is not viable, and since change therfore means the loss of what they feel is the real world, along with all that work they put into creating it, they will do or say almost anything to avoid that loss.

    Scientists who are generally rational men and women are generally incapable of comprehending this behaviour. The view is that once the situation is explained adequately, that reasonable people will be forced to draw the same reasonable conclusions as concluded by the consensus of the scientific community.

    The flaw in that logic of course is that the assumption that the current population (particularly the American population), is capable of drawing reasonable conclusions and capable of honestly applying unbiased logic, is demonstrably false.

    SCIENCE CAN NOT WIN THIS BATTLE in the short or even median term. It will only win once those who harbour this anti-science political ideology have died, and a new generation adopts an ideology that is more in tune with reality.

    I must point out as well that the ideology that is pathalogically ignoring and misrepresnting climatological reality is also working overtime to ignore and misrepresent economic reality. At least in America where dispite the fact that 2 out of every 4 dollars the U.S. Federal government spends is borrowed, Conservatives continue to demand that they are over taxed and that tax cuts – what has produced America’s $14 trillion dollare debt – are the solution to the budget crisis.

    As with the Climate, these American Conservatives can not be reasoned with. They believe that they can reduce federal spending by 50% without any impact on unemployment, or cuts to the U.S. military or significant cuts to the social insurance program. Three programs that far exceed the remainder after their budget cut delusion.

    On this issue, these denialists are even incapable of performing simple addition and subtraction.

    This behaviour is completely irrational of course, and it runs completely against the self interest of those who profess the denialist ideology – a fact that also runs counter to the tenants of their own ideology.

    And just as the climate issue is lost to the short and median term, so too is the American state lost. But permanently in this instance.

    The fate of the United States is oblivion. The fate of Climate Science in America is nill. Get out while there is still time, and try to internationalize as much of Climate Science as possible.

    We are entering into a new dark era.

  27. 227

    185 Judith Curry, amazing I read all this criticism stemming from Montford’s book, unluckily you support these ideas, without one iota of explaining the main conclusion which is rather hard to neglect: 2010 is likely the warmest year in history despite a weaker El-Nino than 1998, and despite solar activity being extremely low.
    Wouldn’t a proper scientific observation start from that point, as a matter to criticize Mike’s work, rather than nit picking details which seem at first glance totally irrelevant to the main issue, the recent warming curve with reconstructions corresponds exactly to what is happening. Would you consider this as a fluke of bad statistics ? Or rather successful science given and achieving good results. I find this disconnect rather glaring, I don’t think you are reasoning this subject with a sound premise to start with. Finding errors is nice, but errors if any does not change the main observation its warmer everywhere on earth, following the path of a reconstructed temperature curve quite well. What ever else you may find pales in comparison, at least acknowledge success, and abound in correcting science when it especially fails.

  28. 228
    Edward Greisch says:

    145 BPL: “The Earth is warming. We’re doing it. And it’s the most serious problem civilization faces outside of nuclear war.”
    We never had enough bombs to make ourselves extinct. We would have needed 10,000 times as many bombs as we ever had to equal an Extinction Level Event [ELE].
    ELE=100 Million Megatons= the impact energy of the bolide that killed the dinosaurs.
    BUT: GW can easily add up to an ELE. The sun can easily provide that much energy and much more if we keep making CO2. GW is worse than nuclear war, even if the nuclear war had happened when we and the Soviets had 30,000 bombs each.

  29. 229
    jo abbess says:


    Ah yes. I see. Judith Curry is very real. Thanks for the link. It is ironic and almost surreal that she holds the employment role that she does and yet simultaneously holds the ideological position that she does.

    May I ask you, and perhaps the other commentators here too : which one piece of research would you beg Judith Curry to read if she could spare the time ? Which piece of data and analysis would shake her from her current energy well and into a new shell of comprehension/vision/getting-it-ness ?

    If she is contributing here, even only a drive-by basis, she must be close to the cusp of change. How can she be metaphysically nudged ?

    Why is she standing up for the rights of McIntyre et al. to hold forth from their various platforms of denigration ? Free speech is all very well, but a lie’s a lie and should not be propagated, especially if it’s couched in emotive, sensationalist, paranoid language.

    Can it be a problem to do with “hate speech at one remove” ? Let me explain. I have exchanged e-mails with a certain Ross McKitrick, whom I’m sure you all know (of) and he is an absolute gentleman in correspondence, most courteous and thoughtful, even though the paper he kindly sent me was full of holes.

    Apparently Steve McIntyre is fairly civil as well, as the British journalists have sucked up everything he’s oh-so-politely spewed recently.

    And we all know that Patrick Michaels is practically an archetypal North American god-spirit of fatherliness, restraint, wisdom and generosity (even though he can be a tad paranoid at times).

    Nigel Lawson is treated as everyone’s favourite wrinkled doting uncle in Britain – genial, congenial and a bit doddery, so give him some respect, shall we ?

    So what is it with these gentlemen denier-sceptic-contrarians ? Pleasant in company, but the content of their accusations, suspicions, doubt-formation, propaganda and dubious “facts” is littered with vile bile.

    It’s like assassination by robot. They didn’t do it. They weren’t there. But the victim was executed all the same.

    What we are dealing with here is over 25 years of active discouragement from the investigation and understanding of Climate Change. Who are the parties that don’t want the general public, the science “laity” to know what is really happening ? Their propaganda techniques are obvious, if you have the shallowest of knowledge about the manipulation of public perception.

  30. 230
    Edward Greisch says:

    Gavin: Is 2% more evaporation from the ocean sufficient to make all the floods we have had in the past 3 years? Somewhere else I saw 4%.

    Disinform for free: I would think they would get tired of it unless they are getting some kind of reward. What? Their operation looks like it must cost something.

  31. 231
    mike roddy says:


    Thanks for once again taking on the unpleasant task of refuting weak and nonsensical arguments in detail. You are really good at it, and I particularly appreciate your candor and impatience with fools. We need a lot more like you.

  32. 232
    Edward Greisch says:

    226 Vendicar Decarian: The psychology of GW denialism is an interesting topic that we do need to understand. The question is: What is the key to unlocking it? I understand that you have given up, but I saw an advertisement for our side on CNN today.

  33. 233
    Ken W says:

    Re: #185 Judith Curry wrote:

    your attempt to rebut my points are full of logical fallacies and arguing at points i didn’t make. As a result, Montford’s theses look even more convincing

    To whom? Gavins responses were excellent and very convincing to a reasonably intelligent 3rd party observer.

  34. 234
    Hank Roberts says:

    > floods
    Hmmmm …. that might be a question for Tamino, did he already address it somewhere?

    I found, well, not much. This seemed close:

    But it’s just a “Letter” and it’s from 2002:

    “… detection of anthropogenically forced changes in flooding is difficult because of the substantial natural variability3; the dependence of streamflow trends on flow regime4, 5 further complicates the issue. Here we investigate the changes in risk of great floods—that is, floods with discharges exceeding 100-year levels from basins larger than 200,000 km2—using both streamflow measurements and numerical simulations of the anthropogenic climate change associated with greenhouse gases and direct radiative effects of sulphate aerosols6. We find that the frequency of great floods increased substantially during the twentieth century. The recent emergence of a statistically significant positive trend in risk of great floods is consistent with results from the climate model, and the model suggests that the trend will continue….”

    You might look at the rather large number of citing papers and see what’s been made of the idea in the past 8 years:

  35. 235
    John Mashey says:

    re: #232
    Psychology yes, but please let’s not start from scratch again.
    at least look at this and this, and if that piques your interest, those are included with more context in Section 2 of PDF @ this. There’s a taxonomy of 25+ observed reasons why people go off into climate anti-science. I make no claim it’s complete or perfect, but it’s a start.

  36. 236
    dhogaza says:

    May I ask you, and perhaps the other commentators here too : which one piece of research would you beg Judith Curry to read if she could spare the time ?

    Given her parroting of Montford’s obvious lies regarding Mann ’08, she could at least read Mann ’08 to see of Montford (who is an accountant with no science training) is telling the truth.

    That’s not so much to ask, right, of a department head in her position?

    Which piece of data and analysis would shake her from her current energy well and into a new shell of comprehension/vision/getting-it-ness ?

    Rumor on the street is that she’s libertarian, and if that’s true, “nothing” is the answer.

    But I don’t know if the rumor is true. Still, she shows no sign of being sensitive to truth (note that her internet posting history, as others here have pointed out, is somewhat lengthy over the past couple of years – apparently she’s posting here to slay the dragon [of truth, sadly, and it won’t work]

    The links to her posts at collide-o-scape are worth following (though you might find my comments close-minded and offensive, though after her show here, maybe not so much).

    If she is contributing here, even only a drive-by basis, she must be close to the cusp of change. How can she be metaphysically nudged ?

    Personal opinion? A better sense of ethics, such as I hold, imparted to me by my conservative fundamentalist Christian mother. (I lost the conservative, fundamentalist Christian bits as I became an adult, but my mother’s condemnation of dishonesty is a lesson I’ve never slacked on).

    Why is she standing up for the rights of McIntyre et al. to hold forth from their various platforms of denigration ?

    Personal politics, I imagine.

    Can it be a problem to do with “hate speech at one remove” ? Let me explain. I have exchanged e-mails with a certain Ross McKitrick, whom I’m sure you all know (of) and he is an absolute gentleman in correspondence, most courteous and thoughtful, even though the paper he kindly sent me was full of holes.

    Apparently Steve McIntyre is fairly civil as well, as the British journalists have sucked up everything he’s oh-so-politely spewed recently.

    If you’re a Yank like me, don’t fall for faux British/Canadian pseudo-politeness. There’s a reason for the fact that European political leaders have sneered at it for centuries, and why Ike and Patton found Montgomery insufferable and (to be blunt) rather stupid.

    It’s an act. The problem, from an American point of view, is that if you ignore the act, and respond honestly, you’ll be told that “your argument is wrong because you’re impolite, regardless of the factual truth or falseness of your words”.

    Oh, wait, Curry just pulled that crap on Gavin in post #185 (and Gavin’s not even a yank!)

  37. 237
    adelady says:

    re#233. Couldn’t agree more. The analyses and responses have been top-notch stuff. From an observer’s standpoint, there’s no question who appears to be more logical, thorough, knowledgeable and polite.

    I’ll be happy to revise that judgement should Ms Curry contribute something equally thorough, erudite and logical.

  38. 238
    Laws of Nature says:

    Hello Gavin,
    RE #175
    [Response: It’s precisely because bristlecone pines respond to their environment that they are useful. Not sure what your point is. – gavin]
    Well, they should not react to environment, but temperature, these trees look so tortured, they would react to anything..!

    [Response: Actual temperature increase is a function of the total forcing, not just CO2 (which, coincidentally, is around 1.7 W/m2 but with error bars of +/-1 W/m2 or so), the climate sensitivity and the thermal inertia in the system. With the best estimates of all of these things, we should have seen somewhere between 0.6 and 1 deg C warming by now. – gavin]

    Well, let me rephrase my question then (and again apologies for being a bit offtopic .. I don’t try to hijack this thread, but honestly puzzled by this):
    Are you saying:
    1.7 W/m^2 x forcing_for_CO2 + other = 0.6 to 1 deg C
    3.7 W/m^2 x forcing_for_CO2 = roughly 3 deg C ?
    This would imply that the “other” could sum up to about -1 deg C?
    Do I see this correctly and what would that be?
    So far I always heard about positive natural forcings like “coming out of an ice age” and “sun spot numbers”.

    [Response: no, you are confusing a transient response with an equilibrium response (which is larger). This is OT on this thread though. No more please. -gavin]

  39. 239
    Edward Greisch says:

    234 Hank Roberts: 109 articles on one list! Thanks! I had a hard time believing my ears on yesterday’s local TV news. A nearby area of Iowa got an incredible rainfall in one day. The city engineers have standard tables for 10, 25, 50, 100, 500, 1000 year floods. It seems that they need to move the flood size 2 steps to the left. The 1000 year flood becomes the 100 year flood or maybe the 50 year flood. GW also explains how all those old houses got built on what is now the flood plain. It is flood plain encroachment on formerly safe dry land. The psychological impact of a flood is so big that it may have something to do with the “Montford Delusion.” AS in: “That can’t happen. You said GW was in the future.”

    It isn’t all local fault for cutting down trees or paving parking lots. That is what we were told for the entire 20th century. RC: This could be a topic for a new article.

  40. 240
    Jacob Mack says:

    Why would people without data and accurate numbers argue with Eli?

  41. 241
    Charles says:

    #185 Judith Curry wrote:

    “… your attempt to rebut my points are full of logical fallacies and arguing at points i didn’t make. As a result, Montford’s theses look even more convincing.”

    And #233 Ken W. replied: “To whom? Gavin’s responses were excellent and very convincing to a reasonably intelligent 3rd party observer.”

    I have to agree with Ken, Judith. Your “drive by” wasn’t very impressive. A more substantive response when you’re not rushing off somewhere might be more appropriate. However, I also think Gavin makes a really important point: MBH98 has received enough attention already.

  42. 242
    ScaredAmoeba says:

    Re: Judith Curry @ 168 & 185

    When a scientist makes false assertions such as yours: you discredit yourself; your university; and science itself. You should be deeply ashamed.

    Thank-you for your careful dissection and debunking of the Montford Drivel.

    Thank-you once again for your tireless rebuttals and explanations.

  43. 243
    calyptorhynchus says:

    Another test you can apply to Montford’s book is the WPI test.

    You ask “who publishes it?”

    Is it
    Harvard UP?
    Yale UP?
    Oxford UP?
    Cambridge UP?

    Or any academic publisher?

    No, it is published by Stacey International (???!!!), that well-know International publisher of quality scientific works (sarcasm emoticon).

  44. 244
    Vendicar Decarian says:

    “The psychology of GW denialism is an interesting topic that we do need to understand. The question is: What is the key to unlocking it?” – 232

    The problem of course, is that there is no cure for self imposed stupidity that results from ideologically based self deceit.

    The point is that you can not reason with the unreasonable. It is a waste of time and effort. This is not to say that you should not try to correct denialist perceptions in the public sphere. One must always fight the good fight, irrespective of the results. However… Putting out reasoned arguments and expecing the public to change it’s view by virtue of their ability to honestly reason is doomed to continued failure in the short and median term.

    Alternate strategies must be employed if there is to be reasonable mitigation of the negative effects of the projected change in climate.

    Scientists have been way too passive and way too accomodating to statements made by liars for hire, dishonest ideologues, and those denialist cheerleaders who tell the ditto-heads what to think and say.

    Any effective strategy must challenge and crush these people in the public arena. You take them one at a time, and you pummel them through all means possible, and through all forum’s possible, including the courts until each is defeated in turn.

    Lets see the APU review the collected works of Inhofe. Lets see Rush Limbaugh taken to court for slander. Grab the public’s attention though unprecedented actions like a national strike among the nations scientists.

    It isn’t rocket science.

  45. 245
    Dale Park says:

    Have I missed something here? Isn’t this whole debate a bit like someone finding an arithmetic error in Galeleo’s first paper and telling us all that we should still believe that the earth is still the center of the universe.

  46. 246
    Michael says:

    Oh dear, the swedish division of the denier zombie army have picked up on this thread and made Judith Curry their new beloved martyr and raves on about how she is schooling “the AGW lead sink” people of RealClimate. Good going dr Curry. There’s your fan base and they are prepared to do anything for you now. And it doesn’t matter what anyone else here is saying. What’s the point…

  47. 247
    adelady says:

    Tireless. Just the word I was looking for. (Ashamed is pretty good too.)

    As for Gavin, Tamino, et al. My admiration grows by leaps and bounds.

  48. 248
    Geoff Wexler says:

    #226 Vendicar Decarian

    Yours is a really cheerful comment to read first thing in the morning: Summary;

    The pessimists guide to thermodymamics.

    1. If a constraint is removed within a system, the latter will reorganise in such a way as to maximise the misinformation.

    2. If two systems are allowed to interact, net misinformation will flow from the more ill informed to the other one.

    Ah… but 2 is incomplete. I forgot to add unless work is performed during the interaction .

  49. 249
    Ray Ladbury says:

    Dale Park,
    You’ve almost got it. It’s like someone who can’t do math thinking that they’ve uncovered an arithmetic error in Galileo’s first paper and thinking they’ve overturned all of physics.

  50. 250
    Lazar says:


    Gavin is right. MM2005 did not “model a stationary process”, they modelled a non-stationary process as a stationary ARFIMA process and unusually did not attempt any validation statistics for their model. The autocorrelation of the ‘blade’ segment of ‘hockey-stick’ shaped proxies is significantly higher than the rest of the series, this biases their estimates of autocorrelation parameters because their model assumes a stationary autocorrelation structure, making their simulated series unrepresentative of most of the length of hockey-stick series, as can be seen in this graph of lag-1 autocorrelation coefficients.