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Hey Ya! (mal)

Filed under: — group @ 30 September 2009

Interesting news this weekend. Apparently everything we’ve done in our entire careers is a “MASSIVE lie” (sic) because all of radiative physics, climate history, the instrumental record, modeling and satellite observations turn out to be based on 12 trees in an obscure part of Siberia. Who knew?

Indeed, according to both the National Review and the Daily Telegraph (and who would not trust these sources?), even Al Gore’s use of the stair lift in An Inconvenient Truth was done to highlight cherry-picked tree rings, instead of what everyone thought was the rise in CO2 concentrations in the last 200 years.

Al Gore apparently confusing a CO2 curve for a tree

Who should we believe? Al Gore with his “facts” and “peer reviewed science” or the practioners of “Blog Science“? Surely, the choice is clear….

Yamal sub-fossil larch trees in river sedimentMore seriously, many of you will have noticed yet more blogarrhea about tree rings this week. The target de jour is a particular compilation of trees (called a chronology in dendro-climatology) that was first put together by two Russians, Hantemirov and Shiyatov, in the late 1990s (and published in 2002). This multi-millennial chronology from Yamal (in northwestern Siberia) was painstakingly collected from hundreds of sub-fossil trees buried in sediment in the river deltas. They used a subset of the 224 trees they found to be long enough and sensitive enough (based on the interannual variability) supplemented by 17 living tree cores to create a “Yamal” climate record.

A preliminary set of this data had also been used by Keith Briffa in 2000 (pdf) (processed using a different algorithm than used by H&S for consistency with two other northern high latitude series), to create another “Yamal” record that was designed to improve the representation of long-term climate variability.

Since long climate records with annual resolution are few and far between, it is unsurprising that they get used in climate reconstructions. Different reconstructions have used different methods and have made different selections of source data depending on what was being attempted. The best studies tend to test the robustness of their conclusions by dropping various subsets of data or by excluding whole classes of data (such as tree-rings) in order to see what difference they make so you won’t generally find that too much rides on any one proxy record (despite what you might read elsewhere).


So along comes Steve McIntyre, self-styled slayer of hockey sticks, who declares without any evidence whatsoever that Briffa didn’t just reprocess the data from the Russians, but instead supposedly picked through it to give him the signal he wanted. These allegations have been made without any evidence whatsoever.

McIntyre has based his ‘critique’ on a test conducted by randomly adding in one set of data from another location in Yamal that he found on the internet. People have written theses about how to construct tree ring chronologies in order to avoid end-member effects and preserve as much of the climate signal as possible. Curiously no-one has ever suggested simply grabbing one set of data, deleting the trees you have a political objection to and replacing them with another set that you found lying around on the web.

The statement from Keith Briffa clearly describes the background to these studies and categorically refutes McIntyre’s accusations. Does that mean that the existing Yamal chronology is sacrosanct? Not at all – all of the these proxy records are subject to revision with the addition of new (relevant) data and whether the records change significantly as a function of that isn’t going to be clear until it’s done.

What is clear however, is that there is a very predictable pattern to the reaction to these blog posts that has been discussed many times. As we said last time there was such a kerfuffle:

However, there is clearly a latent and deeply felt wish in some sectors for the whole problem of global warming to be reduced to a statistical quirk or a mistake. This led to some truly death-defying leaping to conclusions when this issue hit the blogosphere.

Plus ça change…

The timeline for these mini-blogstorms is always similar. An unverified accusation of malfeasance is made based on nothing, and it is instantly ‘telegraphed’ across the denial-o-sphere while being embellished along the way to apply to anything ‘hockey-stick’ shaped and any and all scientists, even those not even tangentially related. The usual suspects become hysterical with glee that finally the ‘hoax’ has been revealed and congratulations are handed out all round. After a while it is clear that no scientific edifice has collapsed and the search goes on for the ‘real’ problem which is no doubt just waiting to be found. Every so often the story pops up again because some columnist or blogger doesn’t want to, or care to, do their homework. Net effect on lay people? Confusion. Net effect on science? Zip.

Having said that, it does appear that McIntyre did not directly instigate any of the ludicrous extrapolations of his supposed findings highlighted above, though he clearly set the ball rolling. No doubt he has written to the National Review and the Telegraph and Anthony Watts to clarify their mistakes and we’re confident that the corrections will appear any day now…. Oh yes.

But can it be true that all Hockey Sticks are made in Siberia? A RealClimate exclusive investigation follows:

We start with the original MBH hockey stick as replicated by Wahl and Ammann:

Hmmm… neither of the Yamal chronologies anywhere in there. And what about the hockey stick that Oerlemans derived from glacier retreat since 1600?

Nope, no Yamal record in there either. How about Osborn and Briffa’s results which were robust even when you removed any three of the records?

Osborn and Briffa (2006) Supplemental Material

Or there. The hockey stick from borehole temperature reconstructions perhaps?

No. How about the hockey stick of CO2 concentrations from ice cores and direct measurements?

Err… not even close. What about the the impact on the Kaufman et al 2009 Arctic reconstruction when you take out Yamal?

Oh. The hockey stick you get when you don’t use tree-rings at all (blue curve)?


No. Well what about the hockey stick blade from the instrumental record itself?

And again, no. But wait, maybe there is something (Update: Original idea by Lucia)….


One would think that some things go without saying, but apparently people still get a key issue wrong so let us be extremely clear. Science is made up of people challenging assumptions and other peoples’ results with the overall desire of getting closer to the ‘truth’. There is nothing wrong with people putting together new chronologies of tree rings or testing the robustness of previous results to updated data or new methodologies. Or even thinking about what would happen if it was all wrong. What is objectionable is the conflation of technical criticism with unsupported, unjustified and unverified accusations of scientific misconduct. Steve McIntyre keeps insisting that he should be treated like a professional. But how professional is it to continue to slander scientists with vague insinuations and spin made-up tales of perfidy out of the whole cloth instead of submitting his work for peer-review? He continues to take absolutely no responsibility for the ridiculous fantasies and exaggerations that his supporters broadcast, apparently being happy to bask in their acclaim rather than correct any of the misrepresentations he has engendered. If he wants to make a change, he has a clear choice; to continue to play Don Quixote for the peanut gallery or to produce something constructive that is actually worthy of publication.

Peer-review is nothing sinister and not part of some global conspiracy, but instead it is the process by which people are forced to match their rhetoric to their actual results. You can’t generally get away with imprecise suggestions that something might matter for the bigger picture without actually showing that it does. It does matter whether something ‘matters’, otherwise you might as well be correcting spelling mistakes for all the impact it will have.

So go on Steve, surprise us.

Update: Briffa and colleagues have now responded with an extensive (and in our view, rather convincing) rebuttal.

759 Responses to “Hey Ya! (mal)”

  1. 501
    Jim Bouldin says:

    On the other hand Timothy (and I agree with your point, 473), it does force people to learn more about the technical issues in order to follow and/or contribute to the discussion. And that’s a good thing.

  2. 502
    Hank Roberts says:

    Jonathan states:
    “It does. By 1 degree for a doubling of CO2….”

    Jonathan, that’s the instantaneous, hypothetical value achievable by doubling the total number of CO2 molecules in the atmosphere, all at once, with no other change.

    You knew that, right? If not, who fooled you? Where did you get the notion this is a number that means whatever you think it means? Seriously, it would help to know your source for the number and how it was presented to you.

    Now perhaps some day, a string theorist/knitter will come up with a way to instantly change the number of CO2 molecules in the atmosphere.

    Say you could just pull an extra loop from each string and thus double the number of molecules in the air; or remove a loop from each string and reduce the total number of molecuels by half.

    That would produce the one degree change you speak of.

    The latter procedure, if practical, would be very useful as a geoengineering tactic (although removing that much carbon and oxygen from the total available might have some consequences for life on the planet in the longer term).

    Now, who told you this “one degree” change was possible?

    You do understand that in reality, it can’t happen?

  3. 503
    Tilo Reber says:

    Eli: #491

    From the paper that you referenced.

    The update of the Tornetra¨sk data, including relatively young
    trees in the most recent period, has significantly reduced
    the mean cambial age of MXD data in the twentieth century
    (Fig. 1a). As a result, the loss of sensitivity to
    temperature, apparent in earlier versions of the Tornetra¨sk
    MXD chronology (Briffa 2000), is now eliminated. Hence,
    this study shows that data with a disproportionately high
    cambial age in the most recent period can create a similar
    ‘‘divergence phenomenon’’ in the late twentieth century.

    “The late-twentieth century is not exceptionally warm in
    the new Tornetra¨sk record: On decadal-to-century timescales,
    periods around AD 750, 1000, 1400, and 1750 were
    all equally warm, or warmer. The warmest summers in this
    new reconstruction occur in a 200-year period centred on
    AD 1000. A ‘‘Medieval Warm Period’’ is supported by other
    paleoclimate evidence from northern Fennoscandia,
    although the new tree-ring evidence from Tornetra¨sk suggests
    that this period was much warmer than previously

  4. 504
    Jim Bouldin says:

    Ray, and especially:

    Briffa, K.R., F. H. Schweingruber, P. D. Jones, T. J. Osborn, I. C. Harris, S. G. Shiyatov, E. A. Vaganov, H. Grudd, J. Cowie (1998). Trees Tell of Past Climates: But Are They Speaking Less Clearly Today? [and Discussion]. Philosophical Transactions, Royal Society of London, Biological Sciences, 353:63-73.

  5. 505
    Deep Climate says:

    Oh dear – Andy Revkin has weighed in.

    Sigh … He just doesn’t get it.

  6. 506
    Hank Roberts says:

    Tilo, that’s why they called it the ‘Medieval’ warm period.
    Because it happened thereabouts and then.

    Have a look at any of the contemporary references. This one has a good clear summary of some of the issues, and the whole idea is fun, if you like neural networks:


    “… dendroclimatic reconstructions based on linear and nonlinear transfer functions have not yet been compared for palaeotemperature proxies such as temperature-sensitive tree-ring chronologies of millennial length.

    Our tree-ring data comes from palaeontological and biological wood samples from northernmost Finland: Lapland. There are several reasons to focus on this region and data. Previous studies have shown that tree-ring growth in this region is highly sensitive to variations in summer temperature (Hustich and Elfving, 1944; Siren, 1961; Lindholm, 1996). Consequently, these tree-ring chronologies have served as proxy records for several palaeotemperature reconstructions ….

    … Due to the similarity of dendrochronological time-series to other palaeoclimatic proxy records such as sclerochronologies and fish otolith series (Strom et al., 2004; Black et al., 2005; Helama et al., 2006, 2007a), we hypothesize that our results could provide information for studies on growth increments of modern and fossilized corals, bivalves and fishes and their relationships to climate ….

  7. 507
    Jim Bouldin says:

    McIntyre, quoted by Revkin:

    “Can you honestly think of anyone in this field who is subjected to more criticism than I am? Or someone who has more eyes on their work looking for some fatal error?”

  8. 508
    dhogaza says:

    Jim, I saw that, too, and almost fell out of my chair …

  9. 509
    ChrisD says:

    TKearney #456:

    <My hometown of Scranton PA was back in the day buried underneath a glacier. … That fact made me a skeptic, since it begs the question of ‘how did the glacier retreat b/4 the coal underneath it was burned.>

    Good heavens. I don’t have a PhD in anything–just a forty-year-old BA–and even I know the answer to that: Things Can Have More Than One Cause.

    People have been dying for millenia, which begs the question of “how did people die b4 there were any guns?”

    (PS: An annoying note on English language usage: “begs the question” doesn’t mean what you think it means.)

  10. 510
    Ray Ladbury says:

    McI: “Can you honestly think of anyone in this field who is subjected to more criticism than I am? Or someone who has more eyes on their work looking for some fatal error?”

    Anyone? Beuhler?

    Gosh, Stevie McI, you know what the real bitch about being a martyr is? You have to find somebody else to drive in that last nail!

  11. 511
    Former Skeptic says:

    “Can you honestly think of anyone in this field who is subjected to more criticism than I am? Or someone who has more eyes on their work looking for some fatal error?”


  12. 512
    Eli Rabett says:

    Eli has put up an extended comment on making the Yamal tree-ring data base public. In short, it wasn’t Briffa’s obligation

  13. 513
    Eli Rabett says:

    As Eli said, Tilo, there is something in there for everyone.

    Hank, neural networks, having no conscious, are ideal for dendrology.

  14. 514
    Deep Climate says:

    Maybe Andy Revkin (and Steve McIntyre) should read this (not my post so much, but the new blogger I discovered).

    Introducing “Delayed Oscillator” or D.O. as I call this blogger. Some key quotes:

    In other words, Yamal’s “enormous HS blade”, said by McIntyre to be like “crack cocaine” for paleoclimatoligists, is much reduced in DO’s first version, using a standard RCS implementation instead of McIntyre’s home-grown version.

    And DO’s conclusion:

    my quick review of these data here shows that including Khadyta River raw data in the Yamal chronology does not result in a more accurate nor precise understanding of past temperatures in the region.

    Yep, he actaully went and compared the two series to the corresponding gridcell temp, and found the new Khadyta series showed modern divergence from 1970 on, while Yamal tracked quite well.

  15. 515
    Tilo Reber says:


    “Tilo, that’s why they called it the ‘Medieval’ warm period.
    Because it happened thereabouts and then.”

    I know that the Medieval warm period happend around 1000 AD Hank. I’m not sure what point you are wanting to make, however.

    My point, is that Rudd gave us an example of a chronology where the MWP is warmer than today. And it’s a northern european chronology. There are many such examples.

    Ely also said that McIntyre was reducing the accuracy of the Briffa chronology by including young trees. Grudd said in the quote I gave that they needed to include younger trees to overcome loss of sensitivity in the 20th century. So what get’s included or deleted in terms of the age of the trees is whatever is needed to reflect 20th century warming. But that same age distribution doesn’t seem to be maintained into the past. In Briffa’s case, the tree rings that defined the second half of the 20th century were, on average, much older than the tree rings that defined the earlier period. Briffa was using Larches, Rudd was using scots pine. The response to aging seems to vary depending on the tree type. What does that do to the uniformitarian principle when the tree rings that you are using for calibration are older than the tree rings that you use for the rest of the period? What does the 20th century divergence problem, as discussed by Briffa, do to the uniformitarian principle. And if you cannot trust the uniformitarian principle how can you make a meaningful comparison between the 20th century and earlier periods. The uniformitarian priciple would seem to make sense. But it requires that you maintain a uniformity of all elements that are sensitive to temperature. Since tree age is one of those element, and since Briffa did not maintain it, there would seem to be a problem.

  16. 516
    Lawrence McLean says:

    Real Climate:
    I notice that global temperature graphs for individual years exhibit a repeating pattern of high temperatures followed by a few declining temperature years, for example:
    To me, it seems to be a very consistent pattern superimposed on the general global warming trend.

    The pattern seems to be similar with my own experience with the seasons in South Eastern Australia. In every year that I remember, as the season progresses from Winter to Summer, at some stage after the initial warming, the weather returns to Winter conditions that persist for quite a few weeks, followed by a more consistent warming into Summer conditions. Note, that even up to the end of December cold snaps can still occur, but this late, they are of short duration. When average climate conditions are examined however, such as:
    the pattern that I describe is not evident.

    It may be interesting to ask for the reason for the Winter to Summer pattern that I observe, however more important is, has any one else noticed the global temperature pattern that I describe and if so has there been any attempt to explain it? Or is it just my imagination!?

  17. 517
    Hank Roberts says:

    Scott asked about the Andrill story and what they might mean by “hard evidence that Antarctica underwent a brief but rapid period of warming about 15 million years before present.”

    Earlier on the page they give some idea: “Among the 1,107 meters of sediments recovered and analyzed for microfossil content, a two-meter thick layer in the core displayed extremely rich fossil content.”

    So the “brief” period lasted long enough to add two meters to the sediment on the seabed. Google ‘Andrill’ for much more, but you’ll find more conference proceedings and news releases than finished and published science papers; it’s early days yet.

    Example: has some pictures of sections of the core identifying changes from diatomite to other kinds of sediment and explaining them.

    This isn’t work that can be hurried.

    Aside — here, the ‘raw data’ consists of huge freezers full of long cylinders of ice.

  18. 518
    Rattus Norvegicus says:

    One thing that hasn’t been mentioned is that Steve has only been after the Yamal data for a couple of years. Not 10 years. Steve is a chronic dissembler, I’m not calling him a liar here, only a dissembler. He has also ignored the issue about who owns the data. In this case, it was only the derived data (the RCS curves and core analysis based on those curves) which Briffa had to disclose. Anything else is governed by agreement between the originators of the data and Briffa.

    In his answer to Tom P, he misses the point: Tom P showed that the RCS method worked as is it should. Eliminating trees by age class produced little change in the reconstruction. At the point where so many trees had been eliminated that a statistically significant recon could not be produced the “hockey stick” was broken.

    Steve is pretty good at hiding what he means when he says “the hockey stick is broken”. The 20th century rise is never shown to be false, the broken hockey stick invariably involves a spike in reconstructed temperature during a period prior to the instrumental record. And the spike is always not statistically significant.

    What Steve has done is show that if you create an invalid reconstruction (he will never call it a reconstruction, but it is invalid) you can show that the MCA (medieval climate anomaly) was warmer than today. He also shows that the LIA (little ice age) was warmer than today. Hmm. If this doesn’t make any of his backers wonder what is going on, it should.

    The only thing McI has going for him is innuendo. His style of argument is to claim a conspiracy, fail to show any evidence of same, post an article which strongly “implies” misbehavior on the part of the researchers he is attacking. Of course when the rest of the world picks up on the obvious implications of his post he says “I didn’t really mean that.” Yeah right. If you keep doing the same thing over and over again, at some point people think that you’re crazy. McI is crazy.

  19. 519
    Marco says:

    Don’t know whether others have already submitted this, but a blogger called “delayed oscillator” has wieghed in with some interesting observations:
    Obligatory reading!

  20. 520
    Mark P says:

    re 453
    “to be an ad hominem it has to be irrelevant”
    No, ad hominem means an attack on the person or their beliefs, not their science.
    Ad hominem attacks are unhelpful to me.
    I want to understand McIntyre’s science, not his beliefs.

  21. 521
    AndyW says:

    I agree with the posts above that don’t like the tone, either here or blogs with the opposite viewpoint. Rather than talking about science in the manner I grew up with it has become a battle and war against an enemy for some reason, a heated bar argument. Perhaps too many laymen and not enough scientists adding their tuppence worth? Too much emotion and not enough clear thinking.

    Considering, if past history is any guide, AGW will be put on the back burner as regards the general public like acid rain and ozone holes before it so all this aggressive chatter is just rather pointless.


  22. 522

    Jim Bouldin (492),

    Thanks for your thoughtful review of the issues; it clarifies a lot.

  23. 523
    Tom P says:


    Thanks for finding this.

    There are severe statistical contradictions in what Steve McIntyre presented, as I have posted directly on CA concerning his preferred series. He has yet to respond.

    But delayedoscillator has put together the best analysis of why the inclusion of the Khadyta data is invalid.

  24. 524
    Tom P says:

    … for the application Steve McIntyre is presenting – I’ve no reason to doubt the data itself!

  25. 525
    Peter Dawe says:

    The tone and “War/Battle” stuff is a relatively new social manipulation technique. Historically called the BIG LIE!

    The technique is to repeat the LIE as often as possible and simply refuse to make any justification of it, apart from any opportunity to discredit the opposition, however small. It came out of the “FEAR, UNCERTAINTY AND DOUBT” (FUD) system.

    Its great asset is you can practice it without any resources apart from access to the media. No R&D etc.

    One of the main objectives of the technique is to consume the oppositions resources in futile rational arguement.

    Possible responses:-
    Ignore them:- Don’t respond, Get on with the real work

    Sue them:- The lie is a lie, and it damages scientists reputation

    Threaten them with future retribution: Start to keep a public list of them and demand that when rationing comes in they are last in the queue

    The New Noah

  26. 526
    CM says:

    Jim Bouldin, thanks for the clear exposition. It’s good to finally have a “tree person” going over this (confirming that Gavin knows his trees, actually: #404, #417). McIntyre hasn’t commented yet as far as I can see.

    One question for clarification: you say (my emphases)

    The Russians state that they use 224 series in their chronology, chosen based on being the longest and most sensitive of the larger set of series, with sensitivity defined by inter-annual response to instrumental temperatures. It is thus highly likely that they chose their 17 modern cores based on these same criteria.

    Hantemirov and Shiyatov 2002 say (at 721)

    These were the longest and most sensitive series, where sensitivity is measured by the magnitude of interannual variability.

    I take it that this means the more sensitive trees are those where tree rings differ most from year to year, without regard to how this variation correlates with a temperature record. This seems to accord with the explanation you subsequently gave at CA of how sensitivity is generally determined in trees before the instrumental record. That still left some people there wondering why the 17 modern series wouldn’t be selected on the same criteria, as I understood your comment to mean that they probably were.

    Was the reference to “instrumental temperatures” just a fluke in your text (which I’ll be saving it for future reference!), or am I missing
    the point here?

  27. 527
    Mark says:

    Ah, Andy is being “an even-handed Voice Of Reason In A Troubled Time ™”.

    Andy, have you said the same complaint on these other blogs, like WUWT and ClimateAudit?

    I know you won’t have done so for The Register (Orlowski doesn’t have talkbacks: he wants One World View in his theses) and neither with Pielke Sr have let comments in his blog.

  28. 528
    Mark says:

    “I want to understand McIntyre’s science, not his beliefs.”

    Well, there’s your problem: no science in McI’s work.

  29. 529
    Mark says:

    “Please compare ,and if possible contrast , the respective hazards to the reputation of science of ignoring modeling uncertainty caveats, and making worst-case outliers the central focus of publicity , in the run-up to Copenhagen and the Cold War media extravaganza styled ‘nuclear winter.’”

    But the apocalyptic extremes are the ones that deniers are working on: the extreme edge that the sensitivity of global temperatures is so very far away from the mean calculated that it ventures into the realms of impossibility.

    The number of AGW scientists promoting a sensitivity over 6C per doubling is infinitesimal.

    The number of AGW denialists promoting a sensitivity of 1C or less is huge.

    Who is working at the extremes here?

  30. 530
    Mark P says:

    Re 492

    Jim, thanks very much for this. A measured, helpful response to my post. I agree with most of your points and find them useful. Cross posting to CA as well.

    I can see where you’re coming from. The objective is to find the “climate signal” in a low signal to noise environment. Your approach (and H&S’s approach) was to pre-select the older trees which may be best responders to the signal. That should pull more signal out of the noise (the non-responding, younger trees). I’m coming from a signal processing background where to get more signal, you increase your sample size and do more and more averaging. Different approaches.

    Your approach kind of makes sense to me if we have a luxury of a large sample size. However it makes me very itchy when we have a very small sample set. The sampling error becomes tremendous.

    >> McIntyre’s focus on the decline in the sample number from 1990 on is almost completely misplaced. […] Rather, he seems to think that low sample sizes in these years will strongly affect the RCS standardization procedure, when in fact it will have almost no impact at all, because there are already over 225 cores used in the RCS sample. This is because all cores are used in RCS standardization, not just modern cores. […].

    I see where you’re coming from, but I disagree. Only the modern cores are used in the calibration. As I see it, RCS is an algorithm whose inputs are 225 tree cores and some calibration factors. Its output is a temperature record. The problem I see is that the only information from which to derive calibration factors is contained in trees which were alive in the instrumental period. This information set is very limited, and no algorithm (RCS or otherwise) can increase the amount of calibration information.

    Let me try and explain my point in more detail. Sorry for the mickey-mouse language, it’s the only way I can think.

    The Briffa (2000) methodology goes as follows
    (1) take a set of tree samples
    (2) define some a-priori selection criteria to select “good climate responders”:- eg species, location, age
    (3) extract the set of tree samples (“responders”) which meet the criteria:- 225 trees in Briffa (2000)
    (4) confirm that the set of tree samples does show a statistically significant climate response
    (5) confirm that any climate response observed in (4) is statistically strong enough to be extrapolated across the entire “good responder” set.
    (6) if (5) is valid, use the entire “responder” set as a thermometer.

    The only information we can use to carry out steps (4) and (5) is embodied within trees alive during the instrumental record:- the “calibration trees”. We must infer the properties of the rest of the set (“long dead trees”) from the calibration trees. In step (4) Briffa (2000) must show a statistically valid correlation between the calibration trees and instrumental temperature and in step (5) it must show that it’s statistically valid to pass properties observed in the calibration trees to the long-dead trees.

    So the results stand or fall on the information embodied within the calibration trees. RCS can’t add more calibration information than there is. The fact that there are 225 trees in the “responder” set isn’t relevant to this part:- RCS is inferring the climate response of around 200 long dead trees from only the information contained in the handful of calibration trees.

    And to paraphrase McIntyre “how can you infer anything useful from so few trees?”. This small a set seems sensitive to sampling errors. Is it enough to disprove spurious correlation in step (4)? Is it enough to be confident we can infer the properties of the long dead trees from the calibration trees. Tom P’s first graph shows this sensitivity. Removing just one of the calibration trees (albeit the most important one, YAD06) changes 20th century results from 2.75 to 2.35 “units”. That seems to me to indicate a large sampling error. When we draw error bars on the Briffa (2000) results they are going to be pretty big – which weakens its conclusions.

    Do you think I have a point?


  31. 531
    ChrisD says:

    MarkP 520:

    <“to be an ad hominem it has to be irrelevant”
    No, ad hominem means an attack on the person or their beliefs, not their science.>

    Actually, if B’s “attack” is relevant to A’s argument and provides evidence that A’s argument could be wrong, it’s not ad hominem even if it’s directed at A rather than specifically at his argument. Discussions of McIntyre’s motivation and accusations of cherry picking aren’t ad hominem arguments, as you suggested in 404.

    There’s a rather good discussion here; one of its key points is how ad hominem is one of the most widely misused terms on the Internets.

    “Ironically, the fallacy is most often committed by those who accuse their opponents of ad hominem, since they try to dismiss the opposition not by engaging with their arguments, but by claiming that they resort to personal attacks.”

  32. 532
    Hank Roberts says:

    > divergence
    Can be caused by acid rain (from coal burning):

    The blog scientists are proclaiming that because the dendro folks aren’t arriving to blog about Briffa, this proves, well, something.

    Looking with Scholar at the publications shows a whole lot of work being done across a wide range of questions. Try ‘ dendroclimatology ‘ and ‘ dendroecological’ as search terms.

    McI was aware of this stuff in 2007 when he presented at the AGU meeting:

    But read the other presentations on the same page for more discussion about other changes associated with recent fossil fuel use: changes in wind, changes in sulfur dioxide from coal burning (without, and in some areas with, scrubbers), changes in aluminum mobility from acid rain, and much else.
    None of this is news, nor being noticed by the blog scientists it appears.

  33. 533
    pjclarke says:

    Yamal – Good news, to Mr McIntyre’s credit he has emailed or commented on the blogs of ‘journalists’ guilty of the more fanciful extrapolations from his Yamal post, Specifically, Melanie Phillips, James ‘MASSIVE Lie’ Delingpole and The Register. To Ms Phillips he pointed out …

    “While there is much to criticize in the handling of this data by the authors and the journals, the results do not in any way show that “AGW is a fraud” nor that this particular study was a “fraud”. There are many serious scientists who are honestly concerned about AGW and your commentary here is unfair to them. […] In my opinion, scientific journals reporting on climate and IPCC would serve the interested public far better if they focused on articulating these issues to the scientific public at a professional level than by repeatedly recycling and promoting some highly questionable proxy studies that deal with an issue that interests me, but which is somewhat tangential to the large policy issues.”

    And in similar emails to the Register and to Delingpole he points out You’ve conflated two different studies. There are many issues pertaining to the Mann hockey stick, but the Yamal controversy is not one of them

    And despite some thinly-veiled insinuations and interesting linguistic excursions, he also said explicitly that whatever else Briffa may be guilty of, he does not believe that Briffa ‘crudely cherry-picked’ his core selection.

    (nb I look forward to quoting that ‘somewhat tangential’ remark next time I am told that alleged flaws in the HS are fatal to the case for action on AGW, ‘who said this…?’…;-). So far it does not seem that the Telegraph or The Register has given their readers the benefit of McIntyre’s update.

    Yamal – Bad news, seems to me that whatever the merits of his other criticisms, the above opinions expressed by McIntyre effectively pull the rug from under most of the assertions of malpractice and Hockey Stick mortality made by Anthony Watts on his blog, and Ross McKitrick in the FP/NP. One wonders when they will be issuing corrections or updates? Perhaps m’learned friends are sharpening their quills, as Eli speculates…

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  35. 535
    Mark says:

    “Considering, if past history is any guide, AGW will be put on the back burner as regards the general public like acid rain and ozone holes before it”

    One reason why acid rain and ozone holes are no longer talked of is because WE DID SOMETHING ABOUT IT.

    Sheesh. There used to be a lot of talk about smallpox.

    When it was eradicated, what happened to all that talk?

    Does this prove that the talk about smallpox was worthless??

  36. 536
    Mark says:

    “And to paraphrase McIntyre “how can you infer anything useful from so few trees?”.”

    Mark P, you are presuming that these are too few a number of trees to make an inference from.

    Yet this is a question asked and answered by statisticians.

    And the paper comes to the conclusion “yes, you can infer something from these numbers of trees”.

  37. 537
    Jonathan Baxter says:

    RE #488: “Don’t be obtuse! Gavin is alluding to the fact that a sensitivity >2 has >2.5 million years of evidence in favor of it, while Lindzen’s “analysis” has… well, none. See the difference?”

    You are wrong Ray. It is very difficult to get published with no evidence in favor of your position. I suggest you read Lindzen’s paper:

    [I am not claiming Lindzen’s sensitivity estimate is the correct one, just that Gavin’s ground for dismissal are not reasonable.]

    [Response: Sorry, but I disagree. If someone claims to have made a perpetual motion machine I don’t need to read up to page 10 to know that they haven’t. The ice ages could not have happened if sensitivity was as low as 0.5 deg C/2*co2. Therefore there is something wrong with an analysis that says it is. -gavin]

  38. 538
    Theo Kurten says:

    Regarding acid rain and ozone holes. Some of the effects of acid rain (e.g. on tree mortality) may have been overestimated, but concerning ozone depletion it looks like the risk was under- rather than overestimated at the time the Montreal protocol was signed. See “What would have happened to the ozone layer if chlorofluorocarbons (CFCs) had not been regulated?”, Mark’s smallpox analogy is apt.

  39. 539
    Ian says:

    Delayed Oscillator has an interesting take; first of 2 posts here:

    from Post #1: “Steve McIntyre has once again stirred the hornet’s nest of online climate change denial with a hasty modification of the Yamal tree ring data published by Keith Briffa and colleagues…

    “The first thing was to emulate the steps that McIntyre had performed (an audit, if you will), leaving aside for the moment whether they are even proper steps from a data point-of-view.”

  40. 540
    dhogaza says:

    “One reason why acid rain and ozone holes are no longer talked of is because WE DID SOMETHING ABOUT IT.”

    Mark beat me to it … let’s hope the poster is right, and that eventually AGW will be put on the back burner for the same reason: that we did something about it. Something sufficient.

  41. 541
    Alfio Puglisi says:

    516 Lawrence McLean:

    in my admittedly limited understanding of the topic, climate oscillations over a few years are mainly caused by the global ENSO oscillation (“El Nino”), the bottom curve on this graph: See wikipedia for an introduction to the subject. See also this article on this very blog.

  42. 542
    Jonathan Baxter says:

    [Response: Sorry, but I disagree. If someone claims to have made a perpetual motion machine I don’t need to read up to page 10 to know that they haven’t. The ice ages could not have happened if sensitivity was as low as 0.5 deg C/2*co2. Therefore there is something wrong with an analysis that says it is. -gavin]

    Likening Lindzen’s argument to one in favor of a perpetual motion machine is, putting it politely, hubris. Not to mention rather denigrating of the editors and reviewers of GRL.

    Lindzen is not saying sensitivity was 0.5 in the last ice age. He only addresses short-term sensitivity in the Earth’s current climate state. However, his results have bearing on the question of long-term sensitivity. As I said above, sensitivity is likely a function of climate state, so it could well be true that today’s sensitivity is different from that deep within an ice age. You may have sensitivity of 6C/2*CO2 (ignoring ice albedo) when things are cold, reducing as the Earth gets hotter and wetter. Nothing I’ve seen in the ice-age studies rules that out.

  43. 543
    Jim Bouldin says:

    CM and Mark P:

    I’ve read your posts (good questions!) and will try to respond at length as soon as I can. Have not read anything at CA since my posts.

  44. 544
    Hank Roberts says:

    AndyW — acid rain and the ozone holes remain a problem, and we are still doing something about those, of necessity. Interesting to see someone like you, a multi-issue denier, surface here claiming these are no longer talked about. Try reading, it’s informative.

  45. 545
    Eli Rabett says:

    Mark P, My impression is that as the RCS method joins the individual cores to each other, it produces a single proxy record. This blending of the older cores with the more recent ones propagates the effect of the older ones into more recent times and visa versa. The final stage is to impose the instrumental record on the single proxy reconstruction, not to fit the most recent ones alone. At least that is what I think is happening.

  46. 546
    Eli Rabett says:

    Well, Eli has been harping on the ownership of measurement data, and it looks like Steve M has finally copped to what happened. He asked Science to force Briffa to give him the Yamal data and Science told him that the Science article did not rely on “measurement data” but on the RCS reconstruction.

  47. 547
    TCO says:

    Steve McI is bloviating about the “silence of the dendros” on his blog. I get so tired of the penny ante blog rabble rouser crap. And this is from someone more conservative than Steve and WAY sympathetic to fault finding in AGW…and even someone who like internet playing around.

    Steve hasn’t even defined WHAT his issue is with Briffa. He comes on and says, “this is the most momentous thing I’ve ever put on my blog…and than doesn’t say exactly WHY. He claims NOT to be alleging fraud (though he sure seems to hint at it and his hoi polloi go right there). So what is his CASE?

    This is a normal part of his bad writing style. He should have a thesis and then SUPPORTS for that thesis. Not a teaser…than a bunch of details…and than a “tada!” without any specific conclusion/allegation.

    This guy needs to write for publication just so that others can efficiently READ and parse his thoughts. Heck, he would improve his OWN ANALYSIS if he forced himself to write real publications.

    And this is not even some “stuffy science thingie” or English prof wannabe attitude. Good BUSINESS WRITING is the same way! I am so amazed that this guy touts himself as some sort of “prospectus writer”. If he tried to sell a company, other than miserable Canadian shell company mining penny stocks, (don’t snip…it’s true and non-actionable) a private equity buyer or sophisticated buyer would laugh at him. No one will bother unwinding the snail shell…things need to be LAID OUT.

    While he has a good vocabulary…it doesn’t MATTER. His disorganized content is an insult to readers. And it is a pattern with the guy from his blogs to his draft publications to his posters to his presentations.

    The guy has a very high IQ. Even poses interesting issues. Heck, I thought just his “grass plots” (tree ring versus age) were “pretty” (in the sense that a scientist would use that word) and could contribute some grains of good practice and insight to the field. But he doesn’t finish off ideas. 5 year tease now!

    After all kinds of time spent parsing the guys stuff (and it was fun at times), I’m just TIRED. I will wait to see what gets settled. If he has something…it will come out. The Y2K and polar station fixes got solved pretty fast (despite the annoying coy manner of presentation by Steve). Even with Briffa…if there is some BREAKTHROUGH insight and Steve is just too lazy to write it up…it will get taken care of. If the point is more subtle and debatable…well, his insights may not find a home, but then that is Steve’s fault for his crappy, lazy, hoi-polloi-playing-to, self-publishing.

    There is NO EXCUSE for this sort of behavior. You don’t have to be a grad student or have a Ph.D. to write properly. Anyone with years of work experience and a high IQ, should be able to write a clear contribution to the science literature just from the Notice to Authors and from reading the literarature (let alone a quick parsing of some of the books that advise on how to write better science papers).

    I honestly think a lot of the issues this guy has in gettin stuff published is because of disorganized arguments, poor writing, etc. I actually think a lot of the issues ALL SCIENTISTS* have in review, come from poor writing, from lack of clarity.

    Finally…it is annoying that the guy claims that his blog is a “lab notebook” and a place for him to do work in progress…then thinks that people need to respond to it! SHEESH!

    *And I believe this to the extent that I would “James Annan Bayesian bet” that several of the RC contributors could help themselves sail through review better with clearer writing! ;) And while I think all scientists could (easily) up their game here…Steve McI is a MESS.

  48. 548
    MRick says:

    All of the temperature charts above all tell a similar story…

    MBH Hockey Stick = Warming started in 1900
    Oerlemans Glacier Retreat = Warming started in 1850
    Osborn/Briffa = Warming stared in 1900
    Borehole = Warming started in 1890
    Kaufman = Warming started in 1820
    Hockey Stick w/o Tree Rings = Warming started in 1900

    What caused the warming from 1820/1900 to 1940 or so? And what caused the pause in temperature rise from 1940 to 1970 or so?

    The CO2 chart shows that CO2 level has been steadily increasing for the past 7500 years, and shows an acceleration of the increase in CO2 level starting sometime just prior to 1750.

    What has been causing CO2 levels to increase for the past 7500 years and what is causing the acceleration in the increase?

  49. 549
    Stephen says:

    Hi Gavin,

    you say:

    “The ice ages could not have happened if sensitivity was as low as 0.5 deg C/2*co2”

    That’s an interesting and definite statement which I’ve not seen before (and boy have I read a lot!). I would like to learn more – can you point me in the right direction please?

    [Response: read up on our articles about climate sensitivity from the index button above. – Gavin]



  50. 550
    dhogaza says:

    I honestly think a lot of the issues this guy has in gettin stuff published is because of disorganized arguments, poor writing, etc

    I thought it had more to do with the fact that he doesn’t submit stuff for publication …