I have written an analysis and replication of the following figure in M&M05:
It is known – in some circles- that this figure is misleading. What I have not seen yet is that the figure should have looked like this:
and also not have seen is that – had M&M done a proper validation of the choice of Principle Components, they would also have found a hockestick in their version of the scaling of the data:
The full report is here (warning, PDF):
Reactions that are directly related to the statistics and R code in this draft are welcome. If you have someting else to say wait until after the first revision.
[M&M05a]: McIntyre, S. and McKitrick, R.: 2005, ‘Hockey sticks, principal components, and spurious significance’, Geophys. Res. Lett. 32, L03710