Gavin Schmidt, Michael Mann, and Scott Rutherford have written a comment letter to the Annals of Applied Statistics to the Hockey Stick busting McShane and Wyner paper covered on WUWT in August.
It’s quite something. Here’s the M&W graph:
It only took reading the first paragraph of the Team paper for me to get cheesed off. Emphasis mine:
McShane and Wyner (2010) (henceforth “MW”) analyze a dataset of “proxy”climate records previously used by Mann et al (2008) (henceforth “M08”) to attempt to assess their utility in reconstructing past temperatures. MW introduce new methods in their analysis, which is welcome. However, the absence of both proper data quality control and appropriate “pseudoproxy” tests to assess the performance of their methods invalidate their main conclusions.
Why am I cheesed off?
The sheer arrogance of claiming improper “data quality control” when Mann himself has issues with his own papers such as incorrect lat/lon values of proxy samples, upside down Tiljander sediment proxies, and truncated/switched data, is mind boggling. It’s doubly mind boggling when these errors are well known to thousands of people, and Mann has done nothing to correct them but then speaks of data quality control issues in rebuttal. And yet Schmidt defends these sort of things on RC. It’s like the Team never read the McShane Wyner paper, because they clearly said this about data issues:
We are not interested at this stage in engaging the issues of data quality. To wit, henceforth and for the remainder of the paper, we work entirely with the data from Mann et al. (2008)
So MW used Mann’s own data, made it clear that their paper was about methodology with data, and not the data itself, and now the Team is complaining about data quality control?
The Team egos involved must be so large that the highway department has to put out orange road cones ahead of these guys when they travel. And they wonder why people make cartoons about them:
They go on to whine about the MWP being “inflated”.
MW’s inclusion of the additional poor quality proxies has a material affect on the reconstructions, inflating the level of peak apparent Medieval warmth, particularly in their featured “OLS PC10”
Well, here’s the thing gents; you don’t KNOW what the temperature was during the MWP. There are no absolute measurements of it, only reconstructions from proxy, and the Team opinion on what the temperature may have been is based on assumptions, not actual measurement. You can’t set yourself up as an authority on knowing whether it was inflated or not without knowing what the temperature actually was. They also rail about “poor quality proxies” (their own) used in MW. Like these?
Half the Hockey Stick graphs depend on bristlecone pine temperature proxies, whose worthlessness has already been exposed. They were kept because the other HS graphs, which depend on Briffa’s Yamal larch treering series, could not be disproved. We now find that Briffa calibrated centuries of temperature records on the strength of 12 trees and one rogue outlier in particular. Such a small sample is scandalous; the non-release of this information for 9 years is scandalous; the use of this undisclosed data as crucial evidence for several more official HS graphs is scandalous. And not properly comparing treering evidence with local thermometers is the mother of all scandals.
Read the entire Team response here, comments welcome.
Backup location in case it falls down a rabbit hole: inpress_Schmidt_etal_2
For balance, the McShane and Wyner paper is available here: https://wattsupwiththat.files.wordpress.com/2010/08/mcshane-and-wyner-2010.pdf ======================
h/t to poptech
UPDATE: Here are some other views:
Jeff Id, The Air Vent:
Luboš Motl, The Reference Frame: