The Null Hypothesis

This post is a follow-on to discussions on the use by Mann et al (PNAS, 2008) of the Lake Korttajarvi varve proxies described by Tiljander et al (2003), at Lucia's Blackboard and at Michael Tobis' Only In It For The Gold.

Nick Stokes asserted,

Mann fixed Tiljander in the SI of the 2008 paper. He did an analysis without it. If the calibration of the proxy doesn’t work, that’s all you can do.

This follows in the footsteps of Gavin Schmidt's analysis at RealClimate.org --

[Response: This issue was discussed ad nausem at Stoat - bring it up there... There is no other possible reconstruction that would use the proxy in another orientation. It is either in the way it was, or it isn't included at all. Both options were published together in the PNAS paper. No correction needed... ]

Emphasis added.

In this post, I argue that understanding the implications of Mann et al.'s use of the Lake Korttajarvi varve series is essential to a reasoned interpretation of their work.