It will take a while to parse Muir Russell. They’ve been working on it for 7 months and I’ve had it for a day. I’m going to place up notes on things as I notice them. At some point, I’ll try to pull together a longer response, but there are lots of interesting things as I read. Here’s an interesting point that touches on some larger issues.

In Fred Pearce’s recent book, he says that Jones told him that Yamal was used in only 3 of 12 AR4 reconstructions – a point which led him (incorrectly) to presume that statements made in McKitrick’s National Post article were “poppycock”:

According to Jones, of the 12 reconstructions used in the last IPCC reconstruction, authored by Briffa and published in 2007, only three contained Yamal data. (Pearce, 101)

The minutes of the April 9, 2009 meeting between the Team and Briffa-Jones say that 4 reconstructions used Yamal (a point re-confirmed in the CRU Response to the Apr 9 minutes)

Prof Briffa responded that the Briffa-Yamal series is only used in 4 of 10 reconstructions in the 4th IPCC reports and none in the 3rd. Salient, s6

In the Muir Russell Report, they say (section 7) that Yamal is used in only 4[2] out of 12 reconstructions in AR4, with footnote 2 saying that a “fifth reconstruction is disputed“. No provenance is given as to how this dispute arises, nor are there any documents at the CCE Review website showing evidence to the panel that Yamal was used in fifth “disputed” reconstruction.





The point at issue here is obviously medieval-modern comparisons. Only 8 of the 12 AR4 reconstructions provide such a comparison (Oerlemanns’ glacier recession; Pollack and Smerdon’s borehole; Rutherford et al 2005 and Briffa et al 2001 go back only to 1500 or 1400.) Using a denominator of 12 rather than 8 for the comparison is what climate scientists call a “trick”.

I visited this topic in October 2009 in two posts during the pre-Climategate Yamal controversy ( Sept 29 here and Oct 28 here, responding to Briffa’s post on the topic here.

The fifth “disputed” use pertains to Hegerl et al 2007. In Briffa’s table here, he says that Yamal was not used in this reconstruction. In my table here responding to Briffa, I observed that Hegerl et al 2007 stated that their “west Siberia long composite involved Yamal and the west Urals composite,” which I took as evidence that they used Yamal, which Briffa interprets otherwise – hence the “dispute”.

Now Jones’ number of three uses presumably arises from the fact that D’Arrigo et al said that they used Polar Urals, but actually used Yamal – a point observed at CA. I suggested to D’Arrigo co-author Rob Wilson that they submit an erratum on this point, but Wilson thought that it was a good idea not to do so. Briffa’s post noted that D;Arrigo’s “Yamal was used, though possibly labelled as Polar Urals” – a statement that I criticized at the time, since there was no actual doubt as to the label in the article – all you had to do was look.

Now what of the mysterious Hegerl reconstruction? Where the use or non-use is a mystery that remained unresolved even after the GBP200,000 inquiry. A question that IPCC Lead Author Briffa is unable to answer. In Sep 2005 as an IPCC reviewer, I asked IPCC to determine which proxies were used in Hegerl et al 2007. When they refused, I asked Hegerl directly (and also D’Arrigo et al). IPCC WG1 Chairman Susan Solomon threatened me with expulsion as an IPCC reviewer if I asked any more authors of unpublished papers for such information. So I wasn’t able to find out at the time.

Climategate correspondence at the time of the NAS panel hearings (March 2006) contains correspondence about a worried Hegerl, afraid of data requests from McKitrick and I and wondering whether it mightn’t be better to remove her reconstruction from the spaghetti graph.

I engaged in lengthy correspondence with Hegerl co-author and husband, Tom Crowley, trying to get information on their proxies and, in particular, their west Siberia composite. That drifted into a huge number of emails without any success. Crowley made fun of this in an interview with Andy Revkin last September.

Hegerl and Crowley were hired by Muir Russell panelist Geoffrey Boulton to the University of Edinburgh. In the Royal Society of Edinburgh’s Copenhagen brief in December 2009, Boulton used the mysterious Hegerl reconstruction.

Only in Team climate science would there be a “dispute” over whether Yamal was used in the Hegerl reconstruction. Be that as it may, you’d have thought that Boulton would have been perfectly placed to get to the bottom of the mystery of whether Yamal was used in the Hegerl reconstruction. Unfortunately, the moment seems to have passed. And thus the dispute lingers on.

And oh yes, it seems like we have a little He Who Must Not Be Named here. Muir Russell is silent on who claimed 5 Yamal uses and there’s no submitted evidence on the point. Can we therefore presume that they read the relevant CA post https://climateaudit.org/2009/10/28/response-to-briffa-on-yamal-impact/ but Gavinesquely didn’t cite it?

The actual issue is the impact of Yamal on the AR4 spaghetti graph. Muir Russell purports to rebut a straw man that Yamal didn’t affect all the reconstructions – a point that I’ll return to. This is a strawman. The original point was that bristlecones and/or Yamal had a material impact on virtually all of the 1000-year reconstructions (seven of eight) – not that Yamal simpliciter affected all the reconstructions. The purported rebuttals completely miss the point. Yamal was Scotty Pippen to the bristlecones’ Michael Jordan. If I said that Jordan and Pippen scored most of the points for the Chicago Bulls. The strawman is to restate that I’d claimed that Pippen scored most of the points, and then purporting to rebut it by showing Michael Jordan highlights. Jordan and Pippen, not Pippen by himself.

Or as I’ve expressed elsewhere. Yamal was like crack cocaine to paleoclimatogists (but bristlecones were heroin.)

relevant comparison for Yamal is thus not 3 out of 12, but 5 out of 8 – something that is a material difference unless you’re a climate scientist.



