Category Archives: Briffa

The NAS Panel and Polar Urals

Now that we know the abysmally low replication of the modern portion of Briffa’s Yamal chronology (something previously unknown to specialists), I’ve been backtracking through some earlier documents to see how this may have impacted past studies. We’ve talked previously about how Briffa refused to provide measurement data to D’Arrigo et al 2006, resulting in […]

Core Counts and Reverse Engineering

Recently, after the posting of the Phil Trans B archive on Sept 8, 2009, I determined that the Yamal data set as used by Briffa is not more “highly replicated” than the Polar Urals data set and thus there is no basis for the preferential selection of the Yamal chronology over the Polar Urals chronology […]

Yamal and the Divergence Problem

One of the aspects of the Yamal discussion that is perhaps clearer to regular CA readers than to new readers is that Briffa’s Yamal chronology was very different from ring width chronologies previously reported in the area (including by Briffa itself.) Shortly after the publication of Osborn and Briffa 2006 and D’Arrigo et al 2006 […]

Yamal and IPCC AR4 Review Comments

I was one of the more industrious reviewers for IPCC AR4. In my Review Comments, I made frequent reference to Yamal versus the Polar Urals Update, expressing concern about the rationale for using Yamal rather than Polar Urals, an issue that is once again in play. Keith Briffa was the section author and can be […]

Gavin's Guru and RCS Standardization

Obviously, there has been considerable controversy over the past few days over the Yamal data. First, let’s observe the continued silence of field dendros on the dispute. None have stepped forward so far to support Briffa’s use of 10 cores in 1990 (and 5 in 1995). As others have observed, their silence is rapidly becoming […]

Keith Briffa Responds

In spite of suffering a serious illness (which I understand to be a kidney problem), Keith Briffa has taken the time to comment on the Yamal situation. The comment should be read by interested readers. If Briffa or any of his associates wishes to post a thread here without any editorial control on my part, […]

YAD06 – the Most Influential Tree in the World

Obviously there’s been a lot of discussion in the last few days about the difference between the CRU 12 and the Schweingruber 34. In making such comparisons, it’s always a good idea to look at the data in detail – something that obviously should have been done by Briffa and the Team before the widespread […]

Verifying RCS Methodology

One reader asked whether my RCS results held up using “standard” software. There is no “standard” software for RCS. It is different than ARSTAN. Further, despite the use of Briffa’s RCS chronologies in many multiproxy studies, until the present data sets were archived, to my knowledge, there were no public examples where both a measurement […]

The Impact of Yamal on the Spaghetti Graph

We’ve been discussing Briffa and Yamal at CA for a couple of years and many, if not most, regular readers understand the significance of the Yamal collapse. For example, as recently as Sept 19, we were observing the dependence of the Kaufman reconstruction on the Yamal series. So the long-sought fresh information on Yamal (and […]

Yamal: A “Divergence” Problem

The second image below is, in my opinion, one of the most disquieting images ever presented at Climate Audit. Two posts ago, I observed that the number of cores used in the most recent portion of the Yamal archive at CRU was implausibly low. There were only 10 cores in 1990 versus 65 cores in […]


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