McIntyre rebuts Schmidt’s Rant on Yamal

Two days ago, NASA blogger Gavin Schmidt posted an extended rant against me at Real Climate, a rant directed in part at my recent poston Yamal.

I’ve now looked through his post carefully and, beneath Schmidt’s fulminations, did not find any rebuttal to any points actually made in my post, as I’ll discuss in detail below. Much of Schmidt’s post fulminates against my criticism of inadequate disclosure of adverse results. This is a large topic in itself that provides a context to the Yamal controversy, but the exposition of this context is lengthy and, in my opinion, the Yamal issues are sufficiently discrete that they can be considered on their own, as I shall do in this post.

The “Insta-Reconstruction”

Schmidt criticized my estimate of a Yamal-Urals regional chronology from the FOI list as merely “insta-reconstruction”, saying:

if any actual scientist had produced such a poorly explained, unvalidated, uncalibrated, reconstruction with no error bars or bootstrapping or demonstrations of common signals etc., McIntyre would have been (rightly) scornful.

While my “insta-reconstruction” was only produced for a blog post, I submit that it was better documented than many tree-ring chronologies in common use, including the three chronologies of Briffa 2000 link. that have been very popular in multiproxy reconstructions. Indeed, if “actual” scientists had provided equivalent detail for the tree-ring chronologies in common use, much of the controversy of recent years would have been avoided.

Even though this was merely a blog post, I provided all measurement data as used, together with code that, in a turnkey method, uploads the data as used and produces the chronology and graphics. The code shows the precise calculation for a an interested critic. The blog post included a graph of core counts, together with the computation. In contrast, no measurement data for the three chronologies of Briffa 2000 (Taimyr, Tornetrask, Yamal) was archived. Nor was it archived for Briffa et al 2008 until I convinced the journal to require it. New measurement data for Esper et al 2009, which addresses Siberia, is not archived. (I recently requested that it be archived, but have received no acknowledgement from either Esper or Hantemirov.)

Nor is it common practice for dendros to show “error bars, bootstrapping or demonstration of common signals” in typical publication of tree ring chronologies. I think that such practices would indeed enhance the articles, but it’s not something that I’ve taken issue with in dendro publications. (Merely getting dendro data has been hard enough.) None of Schmidt’s desiderata appear in Briffa 2000 or for other important tree ring chronologies (e.g. the Graybill stripbark chronologies that are such an important part of IPCC multiproxy studies.) Calculation of error bars for tree ring chronologies seems very much to be desired, but, in my opinion, to do so would require a major improvement in the statistical theory of chronology construction, something that is long overdue.

read the full rebuttal here