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The Relevance of Yamal
The Yamal chronology is relevant both because, since its introduction in 2000, it has been used in virtually all of the supposedly “independent” IPCC multiproxy studies (see an October 2009 discussion here) and because it is particularly influential in contributing an HS-shape to the studies that do not use bristlecones.
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Editing NOTE:
HS-shape = Hhockey Stick Shape
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IPCC AR4 Box 6.4 showed the eight proxies which have been used the most repetitively (this wasn’t its intent.) Of these eight proxies, Briffa’s Yamal (labelled “NW Russia”) is shown with the biggest HS blade, larger even than Mann’s PC1 (labelled here as “W USA”). See here) and tag yamal.
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Figure 1. Yamal Chronology in IPCC AR4 Box 6.4. Labelled as “NW Russia”
In previous posts, I’ve satirized the “addiction” of paleoclimatologists to bristlecones and Yamal as, respectively, heroin and cocaine for climatologists. (In pharmacological terms, upside-down Tiljander would be, I guess, LSD, as the psychedelic Mann et al 2008 is indifferent as to whether proxies are used upside-down or not (cue Jefferson Airplane‘s insightful critique of Mannian statistics.)
Although Yamal and Polar Urals had been long-standing topics at Climate Audit, they first attracted wide attention in late September 2009, when measurement data became available for the three “regional chronologies” of Briffa et al 2008 (Taimyr-Avam, Tornetrask-Finland and Yamal).