RealClimate on Yamal
May 11, 2012
Bishop Hill in Climate: Briffa, Climate: MWP, Climate: RC

Gavin Schmidt has issued the official response to the recent excitement over Yamal. I have to say, even on a brief glance through it is a wild piece of writing.

Briffa, as we know, reprocessed data from Hantemirov and Shiyatov in his 2000 paper on Yamal. He used the same data again in his 2008 paper on regional chronologies. Schmidt says:

McIntyre is accusing Briffa of ‘deception’ in stating that he did not ‘consider’ doing a larger more regional reconstruction at that time. However, it is clear from the 2000 paper that the point was to show hemispheric coherence across multiple tree ring records, not to create regional chronologies. Nothing was being ‘deceptively’ hidden and the Yamal curve is only a small part of the paper in any case.

As McIntyre's article is quite clear that the Yamal regional chronology dates back only to 2006 it can of course not be relevant to the 2000 paper. This is something that he makes quite clear in his article.

One of the purposes of Briffa (2000) was clearly to demonstrate the effect of RCS methodology on the Hantemirov and Shiyatov 2002 dataset. I have no objection to CRU claiming this “purpose” for Briffa (2000).

But, by 2008, this was no longer their “purpose”. Indeed, one doubts whether the editors of Phil Trans B would have accepted a 2008 paper with such a mundane purpose. The actual “purpose” of Briffa et al 2008 is stated quite clearly and was entirely different: it introduced and discussed “regional” chronologies.

Schmidt is therefore engaging in some serious disinformation. Unfortunately, this is not the only occasion. For example, he points out that McIntyre had long ago received "the data" from the Russians who originally collated it. the time McIntyre was haranguing Briffa and Osborn, McIntyre had actually had the raw Yamal data for over 2 years (again, unmentioned on Climate Audit), and he had had them for over 5 years when he declared that he had finally got them in 2009 (immediately prior to his accusations (again false) against Briffa of inappropriate selection of trees in his Yamal chronology).

Schmidt suggests that McIntyre should have assumed that the data as used by Briffa were the same as those used by the Russians. This is an interesting line of argument because of course his colleague Michael Mann has argued vociferously in the past that the only correct place to get the data is from the actual author of the paper (see the Hockey Stick Illusion Chapter 4). However, since we know that the Russians' data was not the same as Briffa's (see the core count profiles for the two versions in this article) Schmidt's argument again looks more like disinformation than an attempt to explain the truth.

In a later section of his posting, Schmidt discusses the November 2009 article that Ross McKitrick wrote about Yamal, the last time there was a blog storm over the series. Readers need to remember that at the time the article was written, nobody knew about the Yamal regional chronology. Schmidt quotes Briffa's response to the McKitrick piece, which formed part of his evidence to the Russell inquiry, and notes his claim that the other sites in the area were "never considered at the time". Schmidt then notes Briffa's earlier statement:

...we had intended to explore an integrated Polar Urals/Yamal larch series but it was felt that this work could not be completed in time

The contradiction between this sentence, discussing the preparation of a regional chronology and the earlier one stating that the extra sites were not considered is clear. Schmidt's implication is that Briffa had misspoken and that he had been clear all along that the regional chronology had been prepared. He'd just run out of time, you see.

There are a number of problems with this story though. Firstly, the quote above doesn't actually say that the work on the regional chronology had been performed, so it represents a very thin defence that Briffa had been open with the inquiry. Moreover, Briffa actually mentioned not considering the other data twice. This is the other occasion, from Briffa's response to McIntyre in October 2009:

However, we simply did not consider these data at the time, focussing only on the data used in the companion study by Hantemirov and Shiyatov and supplied to us by them

And moreover, we know that the regional chronology was in place by 2006. Why was Briffa publishing a paper saying there was no evidence of the divergence problem in his boreal forest regional chronologies when he had a Yamal regional chronology in his hand that said that there was such a problem? Why would he choose to go ahead and use the Yamal-only series, with an absurdly small amount of data too back up any statement about the divergence problem, instead?

(Added note on source of other Briffa quote)

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