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Thursday, April 15, 2010

Eli Rabett takes Fred Pearce and Steve McIntyre to task

The CRU is not pleased with Steve McIntyre

by Eli Rabett, Rabett Run, April 4, 2010

In its response to the Muir Russell commission, the CRU discusses the Yamal imbroglio
Our work later became the subject of widespread misrepresentation in the media, amounting to hysterical and defamatory reporting of a posting on the “Climate Audit” website, managed by Steve McIntyre. McIntyre produced an alternative chronology omitting many of the modern sites we had used and replacing them with data from another single location. This alternative chronology differed markedly from our chronology during the late 20th century. McIntyre implied that this is evidence that Briffa had improperly selected certain tree-ring data, specifically in order to manufacture a false impression of recent enhanced tree-growth in the Yamal region.
This assertion is entirely false. On the contrary, McIntyre’s omission of the data we had validly used and its substitution with data showing an atypical pattern of tree-growth variations in the region, itself constitutes a biased analysis. A detailed refutation of McIntyre’s implied accusations (Briffa & Melvin 2009) was posted on the CRU website ( on 27th October 2009. A copy is included with this submission. This includes details of a recent re-analysis we made of the Yamal chronology, in response to the posted criticisms. In this re-analysis we incorporate additional living-tree data made available by Rashit Hantemirov at our request. The inclusion of the additional samples and the use of improved statistical processing techniques produced only small differences in the tree-growth pattern (see Figure 1.3 below). From this it is clear that our original work was sound and where the CRU Yamal chronology is incorporated in multi-proxy reconstructions, the choice of which version will not significantly affect the outcome of the final reconstruction. 
Figure 1.3 – Extracted from Briffa and Melvin (2009)
Comparison of published and reworked Yamal chronologies. This Figure shows the two earlier versions of the Yamal RCS larch chronology in red (published in Briffa, 2000) and blue (Briffa et al., 2008) compared to the new version, based on all of the currently available data (Yamal_All) for the original (POR, YAD and JAH) sites and including the additional data from the KHAD site (in black). Tree sample counts for this ‘new’ chronology are shown by the grey shading. The upper panel shows the data smoothed with a 40-year low-pass cubic smoothing spline. The lower panel shows the yearly data from 1800 onwards. All series have been scaled so the yearly data have the same mean and standard deviation as the Yamal_All series over the period 1-1600.
And, oh yes, they don't much like Fred Pearce neither
In an article in the Guardian, published on 3rd February 2010, Fred Pearce provides a misleading account of an email relating to this affair. Professor Tom Wigley wrote to Phil Jones on the 5th October 2009, expressing some disquiet that our Yamal analyses might be suspect, from which it is obvious that he had been misled by reading Mcintyre’s posts. Pearce’s article is written in such a way as to strongly imply that Wigley had read the CRU response to this issue (posted on 27th October 2009) and was dissatisfied. In reality, Wigley’s email predates the response by 3 weeks and after he did read it he was fully satisfied, as he explicitly communicated in a later email to a colleague on 3rd February 2010 (
Which James Randerson might be interested in reading
Date: Wed, 03 Feb 2010 15:46:23 -0700
From: Tom Wigley

I can see why you are concerned about Fred’s latest piece in The Guardian. It does look as though he has deliberately chosen dates to make it appear that I was dissatisfied with Keith’s response. Either that or it was a genuine mistake -- or he is simply ignorant and has not seen the full response. Whatever, he really should write an apologetic P.S. to his piece.

I was completely satisfied with Keith’s response. Not only did it answer all of my concerns and questions, but it also shows that the real villain here is McIntyre (although Keith is careful not to draw that conclusion).

I am enclosing a chronology, and my own summary of the issue. Pearce is a good science writer, but he has really dropped the ball in his series of Guardian articles over the last few days. Sad.

Best wishes,
Oh nos! Steve is such an innocent little lamby.


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