In today’s post, I’m going to re-examine (or more accurately, examine de novo) Ed Cook’s Mt Read (Tasmania) chronology, a chronology recently used in Gergis et al 2016, Esper et al 2016, as well as numerous multiproxy reconstructions over the past 20 years.
Jan Esper, prominent in early Climate Audit posts as an adamant serial non-archiver, has joined with 17 other tree ring specialists, to publish “Ranking of tree-ring based temperature reconstructions of the past millennium” (pdf). This assesses 39 long tree ring temperature reconstructions. The assessment is accompanied by an archive containing 39 reconstruction versions, together with the underlying measurement data for 33 of 39 reconstructions.
In today’s post, I’m going to examine Gergis’ dubious screening out of the Law Dome d18O series, a series that has been of long-standing interest at Climate Audit (tag).
Gergis et al 2016 stated that they screened proxies according to significance of the correlation to local gridcell temperature. Law Dome d18O not only had a significant correlation to local temperature, but had a higher correlation to local instrumental temperature than:
In 2012, the then much ballyhoo-ed Australian temperature reconstruction of Gergis et al 2012 mysteriously disappeared from Journal of Climate after being criticized at Climate Audit. Now, more than four years later, a successor article has finally been published. Gergis says that the only problem with the original article was a “typo” in a single word.
Reflecting on then current scandals in psychology arising from non-replicable research, E. Wagenmakers, a prominent social psychologist, blamed many of the problems on “data torture”. Wagenmakers attributed many data torture problems on ex post selection of methods. In today’s post, I’ll show an extraordinary example of data torture in the PAGES2K Australasian reconstruction.
Wagenmakers on Data Torture
Nature’s policies on plagiarism state:
Duplicate publication, sometimes called self-plagiarism, occurs when an author reuses substantial parts of his or her own published work without providing the appropriate references.
Only two Gergis proxies (both tree ring) go back to the medieval period: Oroko Swamp, New Zealand and Mt Read, Tasmania, both from Ed Cook. Although claims of novelty have been made for the Gergis reconstruction, neither of these proxies is “new”, with both illustrated in AR4 and Mt Read being used as early as Mann et al 1998 and Jones et al 1998.
The calculation of the PAGES2K regional average contains a very odd procedure that thus far has escaped commentary. The centerpiece of the PAGES2K program was the calculation of regional reconstructions in deg C anomalies. Having done these calculations, most readers would presume that their area weighted average (deg C) would be the weighted average of these regional reconstructions already expressed in deg C.
Neukom, Gergis and Karoly, accompanied by a phalanx of protective specialists, have served up a plate of cold screened spaghetti in today’s Nature (announced by Gergis here).
Gergis et al 2012 (presently in a sort of zombie withdrawal) had foundered on ex post screening. Neukom, Gergis and Karoly + 2014 take ex post screening to a new and shall-we-say unprecedented level. This will be the topic of today’s post.
Data Availability
