McIntyre’s trick

Steve McIntyre claims:

One version of the trick is used in IPCC TAR. In this version, Mann replaced post-1960 values of the Briffa reconstruction with instrumental values, then did a smooth, then truncated the Briffa reconstruction back to 1960. Post-1960 instrumental values affected the smooth by the arithmetic of the smoothing filter.

Steven Mosher claims that the same “trick” was used in IPCC AR4.

Arthur Smith investigated and shows that the 1960-truncated Briffa curve in AR4 was not padded with instrumental values, but rather with the mean of the adjacent existing values, exactly as stated in AR4.

Smith concludes:

So, conclusively, despite Mosher’s claims of certainty on what the scientists did, he was wrong.

But it sure takes a lot of effort to prove that one claim wrong, doesn’t it?


  1. #1 Mystyk
    June 19, 2010

    It’s the climate version of the Gish Gallop. That’s all it’s ever been.

  2. #2 Steve Bloom
    June 19, 2010

    Nice work, Arthur! Now watch for Mosher to redouble his efforts on other points.

  3. #3 Doug Bostrom
    June 19, 2010

    “…it sure takes a lot of effort to prove that one claim wrong, doesn’t it?”

    Only a few moments are needed to create the error which then replicates with no further exertion on the part of the original author. Replications each require far more time to douse, which almost never happens before each copy has spawned yet again. A Sisyphean task.

  4. #4 toby
    June 19, 2010

    Is McIntyre a manic obsessive? His website now is solely (well, almost) devoted to “Climategate” and only a few insiders seems to be interested in all the twists, turns and ramifications.

    As far as I am concerned, let him knock himself out.

  5. #5 Paul UK
    June 19, 2010

    McIntyre Magic trick?

    Really, I just get the impression that a lot of these people are performers. They seem to be more interested in touring and putting on shows (Watts, Monckton et al).

    They obviously know that they are just putting on a show just to keep going, like a lot of celebrities desperately trying to be seen on TV even though no one is interested in them any more. It pays the mortgage.

    Seems like McIntyre keeps performing the same magic tricks even though everyone has seen them many times before.

  6. #6 Paul UK
    June 19, 2010

    Re toby@5

    His interest in Climagate might be something to do with the fact that he got people to spam the CRU with FOI requests.

    It’s his little project. I think the fact that he started it, he feels obliged to flog it like a dead horse.

  7. #7 J Bowers
    June 19, 2010

    Re 7 Paul UK

    Steven Mosher Says:
    May 3rd, 2010 at 7:53 am |

    WRT FOIA spamming I actaully orchestrated making sure that each country was covered.
    requests that went into cru that took more than 18 hours were rejected
    I know, because I tailor my request to take MORE than 18 hours to see how they would handle such a request. They refused to work on it because it would have taken more than 18 hours.

    So much for assertions that all of the requests were genuinely academic, not orchestrated, and not time wasting.

  8. #8 Nathan
    June 19, 2010

    Wonder if Mosher will show up in any of these threads…

    Probably not!!

  9. #9 TrueSceptic
    June 19, 2010

    8 JB,

    Eli Rabett covered this a few months ago. Here’s the post at Climate Fraudit.

    It’s quite brazen, isn’t it?

  10. #10 Bobington
    June 19, 2010

    Dumb it down for us plebs.

  11. #11 TrueSceptic
    June 19, 2010

    11 Bobington,

    Dumb what down? 🙂

  12. #12 Arthur Smith
    June 19, 2010

    People (like McIntyre, Mosher, and Fuller) have been going on about the “Mike’s Nature trick to hide the decline” in the climategate emails as if it was actually a signal of some real wrong-doing by the scientists. They might have a point if the scientists had actually produced graphs that they claimed to show one thing, but really showed another; concealing the source information in some way for some reason.

    So some of us have been trying to get specific details on where they think specifically that something was pulled over on us. Mosher over at “Scholars and Rogues” claimed a specific version of “the trick” was used in 3 places: a WMO graph, a graph in the third IPCC report (TAR – 2001), and a graph in the fourth IPCC report (AR4 – 2007), while the captions for those graphs in the IPCC cases very clearly stated something different that what Mosher claimed. So if Mosher was right, he had found another false statement by the IPCC (although of a really very minor point, in the scheme of things – endpoint smoothing in one curve among many in one of the hundreds of figures in each report).

    But – Mosher was wrong, at least about the AR4 figure. No data fabrication or manipulation was done at all, the scientists did exactly what they said they were doing in that figure. Which really shouldn’t be a surprise.

  13. #13 frank
    June 19, 2010

    Longer Bobington:

    Why can’t scientists dumb their message down to something we can understand? And, why do scientists treat us like idiots and feel compelled to dumb their message down? Clearly, scientists are trying to indoctrinate us and tell us what to think!

  14. #14 Neven
    June 20, 2010

    I see that Mosher has been posting articles on WUWT recently. Or actually, he copypastes mainstream media articles and precedes them by his one-sentence-judgement. For me, everyone that does something for WUWT looks guilty by association. Mosher must be feeling the power of his ClimateGate waning. Funny, that.

  15. #15 Bernard J.
    June 20, 2010


    I see that Mosher has been posting articles on WUWT recently. Or actually, he copypastes mainstream media articles and precedes them by his one-sentence-judgement.

    That describes somewhat the modi operandi of Sunspot and El Gordo, although they are wont to source less-than-mainstream material, where it suits their purposes.

    If only the latter character were as lately lamented as the former.

  16. #16 Bernard J.
    June 20, 2010


    If only the former character were as lately lamented as the latter

  17. #17 Vince Whirlwind
    June 21, 2010

    El Gordo’s been back.
    He posted his trade-mark non-sequitur with random leap of logic as “Agnostic” in comment #15 under “Africa Not Fighting Malaria”.

  18. #18 John
    June 21, 2010

    A quick IP check should sort out the true identity of Agnostic.

  19. #19 Vince Whirlwind
    June 22, 2010

    Perhaps it would, unless he’s finally got himself a job and has posted from work.

  20. #20 John
    June 22, 2010

    He said he was working from an online publication. The IP address will almost certainly tell us which one.

  21. #21 John
    June 22, 2010

    Because online publications always have big offices. Scrap that, he’s probably working from home.

  22. #22 Arthur Smith
    June 23, 2010

    Note that I only investigated Mosher’s claim about AR4 Fig 6.10. McIntyre may not have been wrong about TAR Fig 2.21, though I hear others are looking into that. I didn’t find anything specific that McIntyre got wrong – until today that is, when he’s chosen to attack me for this post while agreeing that Mosher was wrong (my one specific conclusion). Check out climateaudit for the “Arthur smith” post…

  23. #23 jakerman
    June 24, 2010

    Arthur congratulation.

    I read the exchange at CA and your post has prodded McI into really show himself up.

  24. #24 jakerman
    June 24, 2010

    Aurthur, I notice your post and clear headed persistence also prompted Mosher to recant at least one of his erroneous claims.

    I rearly see so called ‘sceptics’ correct their errors. Thats a tiny fraction of cred restored to Mosher’s ledger. Pity his book didn’t have just the one major error.

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