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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. 551
    David B. Benson says:

    Mark P in comment #520 wrote “I want to understand McIntyre’s science, not his beliefs.” Thanks for the morning’s chuckle.

    MRick (547) — Read climatologist W.F. Ruddiman’s popular “Plows, Plagues and Petroleum” for much of an answer to your question. His professional papers, usually quite readable, about this matter can be obtained from his website.

  2. 552
    Richard Sycamore says:

    Is it true that Steve McIntyre was an IPCC reviewer? This seems hard to believe.

  3. 553
    Snowman says:

    Last week I had to cut two trees in the garden. The cuts were clean, and the rings separation very clear. Just out of interest I looked at the ring formation from the middle to the outside. The differences stood out, and do you know what? They correlated with my diary record of rain fall in the last ten years (my records don’t go beyond 1999. Why should this be? Why should the rings correlate with rainfall. I presume that the CO2 levels have been rising in the last ten years, whereas rainfall fluctuated. I would have expected the rings to get incrementally bigger each year. What’s wrong with the bloody trees? Why cannot they do as you are suggesting they should. Could you help before I give up altogether?

  4. 554

    Regarding the press release at:

    Which states: “Palynomorphs from sediment core give proof to sudden warming in mid-Miocene era”

    Dr. Warny was kind enough to send me the PDF of this paper. The “sudden” time scale the press release refers to is 50,000 years and the “brief” warming was 200,000 years. Looks like the anti-AGW crowd cannot use this for their claims of natural causes. Bummer.

  5. 555
    WAG says:

    A version of the story for laymen like myself:

    There’s a lot of math to slog through on the blogs, and I found it hard myself to tell alot of what was going on. I don’t know what a Gaussian filter is, for instance. So I’d love to get some “peer review” on my layman’s interpretation of the story, to make sure I’m being honest.

  6. 556
    caerbannog says:

    Is it true that Steve McIntyre was an IPCC reviewer? This seems hard to believe.

    Anyone who wants to sign up can become an IPCC “reviewer”. It’s no harder than signing up to become a Microsoft beta tester.

    TCO said,

    5 year tease now!

    McIntyre is quite possibly the brightest (with the possible exception of Dr. Lindzen) of all the AGW “skeptics”. The fact that he (or Lindzen, for that matter) hasn’t produced anything substantive in the past 5 years should tell you something about the strength of the skeptics’ position with respect to AGW…

  7. 557
    Martin Vermeer says:

    Richard, anybody can become an IPCC reviewer… the beauty of it is that it exposes those putting it on their resumés as the ignoramuses (ignorami?) they are ;-)

  8. 558
    caerbannog says:

    Is it true that Steve McIntyre was an IPCC reviewer? This seems hard to believe.

    Becoming an IPCC reviewer is about as hard as becoming a Microsoft beta tester. All you have to do is sign up.

  9. 559

    I assembled some McIntyre quotes, which seem to vary between thinly veiled insinuations of fraud, and retractions of those statements after the damage is done:

  10. 560
    Jim Eager says:

    Re MRick @547: “What has been causing CO2 levels to increase for the past 7500 years and what is causing the acceleration in the increase?”

    Same advise David Benson gave @549: read Ruddiman’s “Plows, Plagues and Petroleum” and/or his published scientific papers.

    Basically human caused increases of methane (which rapidly oxidizes into CO2 in the atmosphere) from agriculture, particularly from growing rice in paddies, and deforestation from clearing agricultural land, thus reducing CO2 absorption.

    The acceleration was caused by the advent of burning fossil carbon fuels on an industrial scale, beginning ~1750, which has, of course, been accelerating ever since.

    The pause in temperature rise from ~1945-1976 was largely due to particulates from accelerated and unregulated WWII and post-war emissions, particularly sulfates — the same stuff that volcanoes eject into the atmosphere that can cause world-wide cooling for a year or so, and that geoengineering proponents advocate injecting into the upper atmosphere to counter current and future warming. These were subsequently greatly reduced by clean air emissions regulations that came into effect in the 1970s in the US and Western Europe. The collapse of the Eastern Bloc in the 1990s cleared even more from the atmosphere.

  11. 561
    CM says:

    MRick (#547), for answers to questions like these, try the reading materials via the START HERE button on the top of the page; for more specialized questions, try the INDEX button.

    Briefly and AFAIK: Current thinking is that the slow 7,000-year rise in atmospheric CO2 was likely a slow refill from the ocean, and from growing coral reefs, after a dip caused by CO2 uptake from spreading forest; the role of early agriculture is disputed. The recent steep rise is undoubtedly from burning fossil fuels, and partly deforestation. Some of the industrial-era warming was due to a stronger sun, and early 20th century warming could be largely natural, though humans likely played a role. But the warming over the 20th century as a whole and since the 1970s in particular, can only be explained by human influence, in particular the warming from CO2 and other greenhouse gases. The 1940-1970 breather likely has to do with other air pollution offsetting greenhouse warming by reflecting sunlight. — For expert knowledge, try those buttons.

  12. 562
    Jim Eager says:

    Richard Sycamore @550, yes, McI is in fact listed as an “expert reviewer,” the IPPC’s own unfortunate term. But keep in mind that virtually anyone could request a review copy of the IPPC’s draft report and submit their unsolicited comment, as long as they agreed not to publicly comment or disclose its contents prior to the publication of the final report. Even Monckton.

    Note the word unsolicited, and the lack of any requirement that those commenting must actually be an expert.

  13. 563
    Jim Eager says:

    Snowman @551, no you are beyond help, just give up. The science is obviously not within your grasp.

  14. 564
    caerbannog says:

    Re: my posts 554 & 556 — my browser crashed as I was posting the first one, so I assumed that it didn’t get through. Sorry about the duplicate.

  15. 565
    Jim Eager says:

    Snowman @551, are you aware that yours is the only comment out of 551 to assert that tree rings should get wider as CO2 increases?
    You might want to at least get on the right page before sitting down at your keyboard.

  16. 566
    pjclarke says:

    >>Is it true that Steve McIntyre was an IPCC reviewer?

    Its an open review process, all one has to do to become an expert reviewer is ask for a copy of the draft, agree to a few T&Cs, and submit comments, so I believe. It does not imply any particular degree of recognition by the IPCC or authority in the subject matter.

  17. 567
    Hank Roberts says:

    Is this the same Richard Sycamore with the long blog track record, or someone new and uninformed who happens to be using the same name?

    The naivete of the questions and occasional excursion into rhetoric that the old Richard would have mocked as ‘warmist’ or credulous is very strange in the context.

  18. 568
    Jonathan Baxter says:

    RE #502: “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.”

    I understand the physics. The way climate sensitivity is usually derived is as a no-feedback number based on purely radiative thermodynamics (hence the application of Stefan-Boltzmann’s law), modified by a feedback multiplier the largest contribution to which is from water-vapor.

    The radiative (non-feedback) number is (relatively) uncontroversial, well understood, and largely independent of climate state. The full (feedback-modified) sensitivity is much more difficult to pin down, depending as it does on not-as-yet fully understood cloud dynamics, and the overall climate state.

    Your assumption that I am being fooled is interesting. You may be surprised to learn that original climate science papers are quite readable for someone with an advanced degree in maths and physics.

  19. 569
    Mark says:

    Further to 560, you don’t have to even submit an opinion on the paper or even read it at all.

  20. 570
    Mark says:

    Strawman ponders: “I would have expected the rings to get incrementally bigger each year.”


    You need more than carbon to make carbohydrates. They require Carbon, Oxygen AND … wait for it … HYDROGEN!

    How what do you think is H2O (water)?

    Strawman then builds his FEG: “Why should the rings correlate with rainfall. I presume that the CO2 levels have been rising in the last ten years, whereas rainfall fluctuated. I would have expected the rings to get incrementally bigger each year.”

    Well the reason for that will be answered by saying “Because your brain isn’t working as shown by your erroneous expectation”.

  21. 571
    Tony says:

    Anthropic burning will reduce the amount of O2 in the atmosphere.Anyone know if there has been any work done on the possible effects?

  22. 572
  23. 573
    Mark says:

    Tony, the dropping level of O2 has been discussed and measured.

    The change in CO2 is a greater percent and therefore of greater concern.

    I’m *certain* that some biologist would like to accept a donation to work on it, though…

  24. 574
    Mark says:

    “The full (feedback-modified) sensitivity is much more difficult to pin down, depending as it does on not-as-yet fully understood cloud dynamics, and the overall climate state.”

    However, it IS absolutely measureable by the historical records.

    And those records can only be reconciled if the sensitivity of global temperatures to a doubling of CO2 is between 2 and 4.5 C per doubling.

    No need to work out the unworked cloud dynamics or the overall climate state, but just the rather mundane assumption that cloud dynamics were not considerably different in the past and that if clouds had a greater feedback to remove warming from CO2 then there must have been a countervailing process that increased it in spite of this effect and stopped the temperature rising being anulled.

  25. 575
    CM says:

    Re: expert reviewers. – Folks, you make the IPCC review process sound like the Oregon Petition. I know it’s an open process, but…? The IPCC Principles, Appendix A: Procedures, states that expert reviewers “may be nominated by Governments, national and international organisations, Working Group/Task Force Bureaux, Lead Authors and Contributing Authors.” Elsewhere it refers to “appropriate” organizations. Doesn’t say asking for a copy will get your name listed in the report. Citation please?

    Besides, it makes fairly good sense to have McIntyre write review comments for the IPCC draft. He was no doubt thorough.

  26. 576
  27. 577
    Mark says:

    “Folks, you make the IPCC review process sound like the Oregon Petition.”

    Lets just say that the mere accusation of being an IPCC expert reviewer has as little to do with whether they have anything relevant to say as the accusation of being on that petition, hmm?

    PS, no McI wasn’t thorough, he was a pain in the arse.

    You can read all the comments and the points he raised were assinine.

  28. 578
    Mark says:

    Heck, CM, Tilo Reber could cite himself as a widely read authority on climate by having posted so many times on RC recently.

  29. 579
    Dan L. says:

    Richard Sycamore at 550: “Is it true that Steve McIntyre was an IPCC reviewer?”

    In the same sense that ketchup is a vegetable, yes.

    Anyone may have preliminary IPCC reports for review, simply by requesting them and agreeing to restrictions on their use. Deniers are fond of doing this and then claiming they have some sort of formal status as part of the IPCC. Monckton is even given to bragging that he shares in the IPCC’s Nobel Prize.

  30. 580
    Jim Eager says:

    CM @573: “Folks, you make the IPCC review process sound like the Oregon Petition.”

    Well, Monckton is also listed as an “expert reviewer”, so feel free to draw your own conclusion on that comparison.

  31. 581
    Hank Roberts says:

    And for next time, this is how you become an expert reviewer.
    Please note that comments are now closed, this is posted solely as an illustration of the process:

  32. 582
    Marcus says:

    “That’s an interesting and definite statement which I’ve not seen before (and boy have I read a lot!).”

    You might also try the IPCC 4th Assessment Report, where they discuss different methods of determining climate sensitivity, one of the major ones being examination of the last glacial maximum (LGM) and using that to constrain climate sensitivity. Or Knutti and Hegerl: : See Figure 3, which shows how almost every method that has been used to determine climate sensitivity comes up with a number that is almost certainly greater than 1.5, and probably greater than 2, mostly likely to be around 3, and possibly greater than 5…

  33. 583
    Eli Rabett says:

    Hmmm. All talk of IPCC reviewers has made Ethon hungry. Did anyone retain a copy of the agreement you needed to join. Eli would not be surprised if that great formalist Persaud was in violation of the agreement he made to join the august circle.

  34. 584
    Ray Ladbury says:

    Jonathan Baxter, Lindzen’s publication relies on some pretty questionable uses of the satellite data, as Chris Colose has pointed out previously. It looks like GIGO to me. The fact of the matter is that every one of the different threads of evidence for climate sensitivity points to a most probable value of 3 degrees per doubling. Every single one. Lindzen’s value doesn’t even fall within the 95% CL for any of these distributions. What is more, you simply cannot get a climate model to produce a climate that is anything like Earth’s with a sensitivity that low.

    It comes down to evidence, and Lindzen has none in his favor and a mountain against him. I have also learned to take anything Lindzen says with enough salt to raise the blood pressure of an entire city. Once I see a scientist making arguments he knows to be false to a lay audience, I know not to believe anything he says.

  35. 585
    Hank Roberts says:

    Ah, there’s always a precedent.

    Found here:

    —- excerpt follows —-

    The essence of the Fortean approach is to present the data — the anomalies, the possibilities — without any further processing, analysis or value judgments. This infuriated many of Fort’s critics, including John W Campbell himself. Campbell felt particularly strongly about this because, unlike Fort’s traditional opponents, he believed fervently that Fort was onto the Truth. In Campbell’s eyes, Fort shot himself in the foot by presenting his data in an obscure, undigested, belligerent form that no scientist was ever going to take seriously. He made this point in a letter to Eric Frank Russell dated October 1, 1952:

    Fort refused to take the trouble to translate his observations into coherent language — language of science. He made the mistake. If you have something to say, it’s up to you to say it right…. It counts when you can reach an understanding that is valid, and communicate that understanding to others. Fort couldn’t. He did it wrong. He angered the best thinkers, the clearest, straightest-thinking minds who could have helped most. His writings appealed largely to muzzy-minded people who went in for fortune-telling, crystal-ball readings, and the like; they were the bulk of his audience…. His data was valid. It contained important understandings, and important clues. In that, he was right. But why didn’t he do some of the hard work of integrating it and finding the pattern, instead of frothing about how everyone else wouldn’t do that work?

    From The John W Campbell Letters, volume 1 (AC Projects Inc, 1985).

  36. 586
    Karl E says:

    Ok. I don’t get it. Why the sic for the MASSIVE lie? Is it just the orthographic styling or is it something else?

  37. 587

    The foremost Dutch climate skeptic, Hans Labohm, also frequently mentions that he was an IPCC reviewer, and is therefore qualified to comment on the reports as an authority. He’s more Moranesque than McIntyrian though. According to him, the NIPCC report (the latest of which he was a co-author on) is the best report ever written on climate change. (

  38. 588
    Dappled Water says:

    #553 – whew, I thought Snowman was going to say all the large growth rings correlated with dead donkeys.

  39. 589
    CM says:

    Re: IPCC review process

    I don’t materially disagree with anyone that in principle any flake can be an IPCC reviewer if nominated, and nomination is open to many interests. Question is, is it really as simple as asking for a copy and signing a non-disclosure statement, or is this just a meme doing the rounds?

    (If you think this is a silly question to waste time on while the ice caps are melting, well, you’re right, I just got stuck in. Please skip ahead.)

    Hank (#576), apologies, I should have mentioned I’d already looked up Deltoid referencing Stoat. Looked meme-ish. As for that open call for reviews (#581), it was solicited on behalf of the State Dept. to inform the U.S. Government Review. It explicitly asks people to keep this apart from the direct expert review we’re talking about.

    Mark, Dan (#578-9), the individual IPCC reviewers are listed, with affiliations, in annexes to the WG reports (

    Jim (#580), Monckton is not listed as an expert reviewer as far as I can see (AR4 or TAR). Though I would not be in the least surprised if he’s convinced himself as well as others that he is. Meme.

    McIntyre and McKitrick, on the other hand, are both listed in WG1 (as are such phenomena as Vincent Gray and Miklos Zagoni). McIntyre cites a letter of invitation from the IPCC informing him he’d been nominated.

    Eli’s (#583) instincts are keen. In the same post, McIntyre boasts how Susan Solomon admonished him to stop abusing his reviewer status to pester JGR for supporting materials…

  40. 590

    Richard Sycamore:

    Is it true that Steve McIntyre was an IPCC reviewer? This seems hard to believe.

    It’s true. Anyone can become an official “IPCC reviewer” simply by requesting that the IPCC send you a copy of the report.

  41. 591
    Nige says:

    I am a published author and wholey support RC

    There is an issue here over communication.
    If scientists want to carry on reseaching, publishing, researching, publishing thats fine.
    If scientists want to change the world, or even Public Policy, they/we need to communicate more effectively.

    We have made a Massive Balls of this debate. No doubt. And I am sorry if that comes as a shock to you.

    We have unequivocal data on atmospheric change in CO2, and somehow, we have called the result ‘Global Warming’. This is dumb, (not because it wont happen), but because it is not understandable by Public Polciy makers, Broadcasters, nor the public.

    When we have a couple of cool summers, or when folks quote the MWP, or when another el nino occurs, the fabled ‘Global Warming’ is ridiculed.

    We need to keep on shouting about the rise in CO2 data (especially ice-core measurements) and ramming home the hypothesis about the link between rise of C02 and burning fossil fuels, and the alterations man has made to the Carbon Cycle.

    Once this link has been accepted, then we can communicate what will inevitably follow – in my humble opinion.

  42. 592
    Mark says:

    “Question is, is it really as simple as asking for a copy and signing a non-disclosure statement, or is this just a meme doing the rounds?”

    Strange. Did you post this before or after Hank gave a link in #581?

    If you did, read the link.

    It isn’t a meme.

  43. 593
    Mark says:

    Bert, doesn’t “sic” stand for “as it is stated” (i.e. “well, they said that”).

    If so, then MASSIVE (sic) is correct.

    Denialists call it a MASSIVE lie (not even massive, MASSIVE). But it is neither massive nor a lie. It’s just what they said, admitting no validity to it.

  44. 594
    Mark says:

    Sorry that should have been addressed to Karl.

  45. 595
    Tony says:

    The point about man’s burning of carbon is that it combines with oxgen to form co2, and we know that a proportion of the co2 is absorbed in the oceans, and in biomass. And so, we are also losing that equivalent amount of oxygen from the atmosphere. Such a loss will cause a reduction in overall sea-level atmospheric pressure. This will result among other things in an adiabatic cooling of the atmosphere, and a lowering of the average sea-level temperature.

    As there is a history of sea-level barometric pressure readings, is there such a thing as global average sea-level pressure graphs, similar to those global average sea-level temperature graphs, which shows the pressure drop from the sequestration of O2?

  46. 596
  47. 597
    CM says:

    Mark (#590), of course I read it, since Hank (#581) was nice enough to find it for me. As you might have noticed, I pointed out (#588) that the link solicited input to the U.S. government review, not individual participation in the expert review. Maybe this open call is where the meme originated.

  48. 598
    Jim Bouldin says:

    CM (526):

    Yes, you interpreted correctly. When I mentioned the instr. record, I didn’t mean comparing to the sub-fossil wood, which is of course, impossible. I meant that one’s ultimate confidence that certain trees (defined by taxon, site conditions, geography, etc.) will in fact function as thermometers, is based on comparisons of modern trees against the instr. record, often in the form of extensive field experience (Shiyatov for example has been working with Siberian Larch in the Urals area since the early 70s, so you can bet he knows very well how that species responds to various site and climate conditions). One then looks for the same types of high to medium frequency patterns in the old wood, as well as the spatio-temporal coherence in particular patterns that would indicate a common response to a given forcing, which in this case is surface temperature. Having said that, this ultra-long chronology work involving buried tres is entirely unique and presents some challenges that most dendro work does not have. There is much more to it then what I’ve said here.

    Mark P:

    Yes you do have a point regarding calibration, but are also sort of missing some points that come from knowing about dendro science practice. My argument was that McIntyre has argued that there’s been this drop in sample size recently (10 trees in 1990, 5 in 1995), and that this somehow affects or is related somehow to the RCS standardization procedure (although he’s said quite a number of things and I’ve lost track of exactly what all). It’s not. That procedure simply averages the up to 241 tree ring widths (224 sub-fossil and 17 modern (Briffa used 10 or 12)), and then subtracts that average from each of the individual tree ring series (to thus estimate, and remove, the size-related growth trend from each). There are no “calibration factors” involved in the RCS process–it’s just an averaging and subtracting algorithm. The resulting growth ‘residuals’ are then averaged, this time by calendar year not ring year, and this mean anomaly is then used to estimate the former temperature anomalies, using the relationship from the calibration of modern trees and the instr. record. (As an aside, we have to assume that McIntyre in fact detrended the Schweingruber data using the RCS method on the 224 + 34 series, but I’m not sure).

    The calibration is based on any trees that grew during the instrumental period for the Yamal region. These trees were collected from several locations (as they should be). Although a larger sample size is always better, exactly how big a sample is big enough depends on the growth variance between the trees, which could be small if the trees are strong responders and the Yamal is characterized by a relatively homogenous summer temperature regime. The one extreme tree you mention is not enough to establish that the 10 or 12 Briffa used were faulty, particularly since the magnitude of the high frequency variance in the sub fossil wood is also a factor here. All of this is what Gavin was referring to when he said it ‘depends on what you are comfortable with’ in his earlier response to you (comfortable in the sense that the calibration is good enough to extract a temperature signal from the old wood).

    Although I don’t know for sure, what I strongly suspect is that the Russians have such an extensive, working knowledge of the area, and the growth response of larch and spruce in it, that they were quite confident that the 17 live trees they used captured the essential summertime temperature pattern of the region. This also is not an uncommon practice in dendroclimatology, although I agree strongly that the details of the calibration relationship should be presented, as well as the details of how the sub-fossil specimens were selected from the larger set, including their spatial info.

    If I had the time, I’d do some analysis of all the data. But I don’t. And thus that’s it for me on this topic–have given it way too much time that I don’t have already. Hope this helps.

  49. 599
    Mark says:

    What meme, CM?

    Are you taking the meaning of meme in its exact sense, in which case, this can be replaced with the word “fact”.

    If so, can we use that word instead of meme.


  50. 600
    Hank Roberts says:

    CM, no, I’m not sure where you’ve gotten the idea that we’re not telling you the truth. Can you tell us your source?

    Yes, the government invited comments, I pointed you to an example, but no one needed to wait on an invitation to submit comments–anyone could, and did.

    Try the Wayback Machine if you don’t believe everyone who’s been telling you this. The IPCC pages no longer have the active links that were there when comments were being accepted but you can find the old archived copies, or spend a little time and find it for yourself.