Steve McIntyre reports (via commenter AMac) that Mann’s inverted Tiljander sediment data lives on in Kemp et al 2011 like some zombie that will not die. I feel for graduate student Kemp, who will forever have the stink of Mann’s inability to admit and correct this simple issue tied to his paper.
Yesterday, Kemp et al. 2011 was published in PNAS, relating sea-level variation to climate over the past 1,600 years (UPenn press release). Among the authors is Prof. Mann. (Kemp11 is downloadable from WUWT.) Figs. 2A and 4A are “Composite EIV global land plus ocean global temperature reconstruction, smoothed with a 30-year LOESS low-pass filter”. This is one of the multiproxy reconstructions in Mann et al. (2008, PNAS). The unsmoothed tracing appears as the black line labelled “Composite (with uncertainties)” in panel F of Fig. S6 of the “Supporting Information” supplement to Mann08 (dowonloadable from pnas.org).
This is one of the Mann08 reconstructions that made use of the four (actually three) uncalibratable Tiljander data series.
As scientist/blogger Gavin Schmidt has indicated, the early years of the EIV Global reconstruction rely heavily on Tiljander to pass its “validation” test: “…it’s worth pointing out that validation for the no-dendro/no-Tilj is quite sensitive to the required significance, for EIV NH Land+Ocean it goes back to 1500 for 95%, but 1300 for 94% and 1100 AD for 90%” (link). Also see RealClimate here (Gavin’s responses to comments 525, 529, and 531).
The dependence of the first two-thirds of the EIV recon on the inclusion of Tiljander’s data series isn’t mentioned in the text of Kemp11. Nor is it discussed in the SI, although it is an obvious and trivial explanation for the pre-1100 divergence noted in the SI’s Figures S3, S4, and S5.
Peer review appears to have been missing in action on this glaring shortcoming in Kemp11′s methodology.
More than anything, I am surprised by this zombie-like re-appearance of the Tiljander data series — nearly three years after the eruption of the controversy over their misuse as temperature proxies!
For those that don’t know this story, here’s some links to get yourself up to speed. In a nutshell, Mann took some sediment data, inverted it in sign, and even though the scientist (Tiljander) who gathered and published the data says it is inverted, Mann has done nothing about it, and it continues to find its way into peer reviewed literature.
AMac has more at his blog: The Tiljander Data Series Appear Again, This Time in a Sea-Level Study. Apparently, realclimate.org won’t allow him to comment on the issue.
Here’s a graph from an earlier CA post: More Upside-Down Mann
Imagine the caterwauling if we published the bottom graph regularly:
Here’s some links for background:
Here’s an interesting use of upside down graphs followed by a consensus insistence that the orientation of the data is correct:
* That’s an actual company http://www.zombiedata.com/