Yamalian yawns

So on to Yamal. The original data for the Yamal series came from two Russian researchers (Rashit Hantemirov and Stepan Shiyatov), and was given to CRU for collation with other tree-ring reconstructions (Briffa, 2000). As a small part of that paper, Briffa reprocessed the raw Yamal data with the regional curve standardisation (RCS) technique. The Russians published their version of the chronology with a different standardization a little later (Hantemirov and Shiyatov, 2002). 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.

Another little appreciated fact: When McIntyre started to get interested in this, he asked Briffa for the underlying measurement data from Yamal and two other locations whose reconstructions were used in Osborn and Briffa (2006). In May 2006, Briffa politely replied:

Steve these data were produced by Swedish and Russian colleagues – will pass on your message to them

cheers, Keith

Briffa was conforming to the standard protocol that directs people to the originators of data series for access to the underlying data, as opposed to the reconstructions which had been archived with the paper. McIntyre expressed great exasperation at this point, which is odd because in email 1548, McIntyre is quoted (from Sep 26, 2009 (and note the divergence in post URL and actual title)):

A few days ago, I became aware that the long-sought Yamal measurement data url had materialized at Briffa’s website – after many years of effort on my part and nearly 10 years after its original use in Briffa (2000).

To which Rashit Hantemirov responds:

Steve has an amnesia. I had sent him these data at February 2, 2004 on his demand.

Thus at 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).

Back to the main story. Of course, regional reconstructions are a definite goal of the dendro-climatology community and Briffa and colleagues have been working on these for years. Some of those results were published in Briffa et al (2008) as part of a special issue on the boreal forest and global change. Special issues come with deadlines, and as explained in a submission to the Muir Russell inquiry, a regional Yamal reconstruction putting together multiple sources of tree ring data was indeed ‘considered’ but wasn’t finished in time. McIntyre’s claim of deception comes from a strained reading of the MR submission (it is actually quite good reading). In response to extended (and yet again false) accusations from Ross McKitrick in the Financial Post:

Between these [two other reconstructions] 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 and Briffa made the decision to reprocess the Yamal ring-width data to hand, using improved standardization techniques, and include this series in the submitted paper [Briffa et al., 2008].

Subsequently, in response to the issues raised by McIntyre, we explored the use of additional ring-width data local to the Yamal sub-fossil data. This work established the general validity of the published Yamal chronology information, albeit with significant statistical uncertainty, including during the medieval time and the late 20th century. [Refers to the online Oct 2009 response]

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  1. K.R. Briffa, "Annual climate variability in the Holocene: interpreting the message of ancient trees", Quaternary Science Reviews, vol. 19, pp. 87-105, 2000. http://dx.doi.org/10.1016/S0277-3791(99)00056-6
  2. R.M. Hantemirov, and S.G. Shiyatov, "A continuous multimillennial ring-width chronology in Yamal, northwestern Siberia", The Holocene, vol. 12, pp. 717-726, 2002. http://dx.doi.org/10.1191/0959683602hl585rp
  3. T.J. Osborn, "The Spatial Extent of 20th-Century Warmth in the Context of the Past 1200 Years", Science, vol. 311, pp. 841-844, 2006. http://dx.doi.org/10.1126/science.1120514