Bradley on the Hockey Stick 2
Sep 10, 2011
Bishop Hill in Books, Climate: other

Time after time when reading Bradley's defence of the Hockey Stick, I was struck by how he avoided the criticisms that were actually made of the paper, preferring instead to knock down a series of strawmen. There are also parts that are grossly misleading.

Take this next excerpt for example, where Bradley describes McIntyre and McKitrick's Nature submission in 2004.

The authors then went on to make a similar pitch to the editors of Nature, who asked us to respond. Once they read our response it was clear that there was no point in publishing the discussion and so the criticism was rejected.

Coming after a long section in which Bradley belittles the M&M critique of the Hockey Stick, anybody reading that would surely conclude that there was a problem with the content of the M&M paper, an idea that can be assessed by reviewing the Nature correspondence.

Or what about the bit where he touches on the statistical issues:

...Detective Mann was on the case and soon discovered the reason [why M&M's result was so different]: they had not, in fact, repeated our analysis in the same way.

By changing the statistical procedure, these critics had effectively eliminated a sizeable set of data from the western United States. It was no surprise, then, that their graph was quite different from ours. Instead of a hockey stick-shaped curve, theirs was more U-shaped, with strange warm period in the fifteenth century...This flew in the face of all that we knew about the fifteenth century, a time when glaciers advanced around the world.

I suppose you can say that it is true that they had not repeated the analysis in the same way - they had of course corrected a significant error in the statistics. I leave readers to make up their own minds about how straight Bradley is being with his readers when he tries to pass this off as a failing of M&M.

McIntyre's position to on the MWP is, I believe, that he doesn't know whether there was an MWP or not, but he thinks it unlikely that tree rings will ever be able to tell us the answer. He has explained many times that he and McKitrick have not created an alternative reconstruction, they have simply shown that Mann's result of no MWP is only obtained by using dodgy data and incorrect statistics. If by processing the dodgy data in a statistically correct manner, you get a "strange warm period in the fifteenth century", that simply reinforces the point that tree rings don't have the answer.

Presumably Bradley knows this though.

Article originally appeared on (http://www.bishop-hill.net/).
See website for complete article licensing information.