Paul Krugman is considering Michael Mann this morning. Amazingly, the great man is trying to resurrect the Hockey Stick.

Mann, as some of you may know, is a hard-working scientist who used indirect evidence from tree rings and ice cores in an attempt to create a long-run climate record. His result was the famous “hockey stick” of sharply rising temperatures in the age of industrialization and fossil fuel consumption. His reward for that hard work was not simply assertions that he was wrong — which he wasn’t — but a concerted effort to destroy his life and career with accusations of professional malpractice, involving the usual suspects on the right but also public officials, like the former Attorney General of Virginia.

He wasn't wrong? Like our friend Anders, Mr Krugman could really do with getting himself a copy of The Hockey Stick Illusion. Like Anders, I don't suppose he will.

Mr Krugman, you really do need to centre your data if you are going to do principal components analysis. Really you do. There is not a reputable statistician who has ever looked at this question and concluded that Mann got it right. I wonder if Mr Krugman is a fan of the Mann view that not centring your data properly is "modern" (and therefore OK) or whether he favours the Gerald North view that you can use a biased method and inappropriate data and still arrive at the right answer.

Homeopathy has nothing on climate science.