Friday, October 30, 2009

Upside Down Mann Hockey Stick

From Climate Audit Oct 29, 2009
Upside Down Mann

The issue with Mann's use of the Tiljander proxies isn't just that he used them upside down (which he did). The problem is worse than that. The Tiljander sediments are the combination of two unrelated processes: a presumably climatically driven process in which narrow sediments are interpreted by the authors as "warm" and thick sediments as "cold" and a nonclimatic process in which sediments are produced by ditches, bridges and farming.

It is definitely and incontrovertibly upside down.

The reason why it is upside down is the spurious correlation between the nonclimatic sediments from bridges and farming and temperature, which confuses the Mannian meatgrinder algorithm.

Perhaps Connolley is gradually realizing that the problem is not just the upside down proxy, but a package of issues including modern contamination and spurious regression.

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