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 […]
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 […]
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. […]
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 […]
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 […]
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 of the AD1400 weights […]
In today’s post, I will report on some excellent work on MBH98 by Hampus Soderqvist, who discovered an important but previously unknown Mike’s Nature Trick: Mann’s list of proxies for AD1400 and other early steps was partly incorrect (Nature link now dead – but see NOAA or here). Mann’s AD1400 list included four series that […]
Continued from here. The Dirty Laundry residual datasets for AD1000, AD1400 and AD1600 were each calculated using Mann’s “sparse” instrumental dataset, but the resultant sigmas and RE(calibration) statistics don’t match reported values. In contrast, the Dirty Laundry residual dataset for the AD1820 step, which was calculated by Tim Osborn of CRU because Mann “couldn’t find” […]
Continued from previous post link. The data associated with the Climategate “dirty laundry” email had other interesting information on Mann’s calculation of confidence intervals and the related calculation of RE statistic. This post draws heavily on offline comments by Jean S and UC, both long before and after Climategate. The left panel below is Tim Osborn’s […]
As the date approached for the Mann-Steyn/Simberg libel trial, I’ve been reviewing my files on MBH98 and MBH99. It’s about 15 years since I last looked at these issues. While revisiting these issues, I re-examined some data associated with the notorious “dirty laundry” Climategate email (link) – excerpt shown at right – that turns out […]
Climate Audit 