Recently, while re-examining PAGES2K, the current paleoclimate darling, I noticed that PAGES2K(2019) reverted to a variation of the Twisted Tree Heartrot Hill (Yukon) [TTHH] tree ring chronology that we had already criticized in 2003 as being obsolete when used by Mann et al 1998.  PAGES2K was supposed to be an improvement on Mann et al 1998 data, but,...

Today’s article is about one of the D’Arrigo et al 2006 datasets. D’Arrigo et al 2006, then under submission, had been cited in drafts of the IPCC Fourth Assessment Report. I had been accepted as an IPCC reviewer and, as an IPCC reviewer, I asked IPCC to make the data available to me or to ask the lead author to make the data available. That prompted...

MBH98 used three Jacoby tree ring chronologies from Alaska: Four Twelve (ak031) – discussed here, Arrigetch (ak032) and Sheenjek (ak033). Sheenjek will be discussed in this article. In our compilation of MBH98 in 2003, we observed that the Sheenjek chronology archived at NOAA Paleo was not the same as the “grey” version used in MBH98.   While we used...

Four Twelve (Alaska) was one of the 11 Jacoby and D’Arrigo series used in MBH98. In our original 2003 article, we observed that the MBH98 version of this chronology differed substantially from the chronology officially archived at NOAA, and, in our sensitivity study, used the archived version (after using the MBH version for benchmarking.)  Among other...

We’ve long discussed the bias imparted by ex post selection of data depending on whether it went up in the 20th century.  Likening such after-the-fact selection to a drug study carried out only on survivors. The Jacoby and d’Arrigo 1989 network was a classic example: the original article reported that they had sampled 36 northern treeline sites, from...

In numerous ancient Climate Audit posts, I observed that all MBH98 operations were linear and that the step reconstructions were therefore linear combinations of proxies, the coefficients of which could be calculated directly from the matrix algebra (described in a series of articles.)   Soderqvist’s identification of the actual proxies enables calculation...