McIntyre and McKitrick have done a great job casting doubt on the first part of the Mann "Hockey Stick" and I will be surprised if the IPCC can still retain it in its original form.
However, we are still up against the second part of the "Hockey Stick" the alleged surface temperature record, as promulgated by Jones, Hansen and Karl., which continues to claim that the current temperature is "unprecedented"
Very little has been done to challenge the accuracy and reliability of the surface record.
I am attaching my own modest attempt, which was originally submitted to Geophysical Research Letters but after interminable delays was originally published on John Daly’s website, where it can still be seen.
It consists of a study of the 5°x5° average temperatures, as calculated by Jones et al from 1900 to 1996, divided into rational regions. I show that there is great variability between boxes, and regions, with much discontinuity of records. I showed that the Russian/Siberia results had a large influence on the averages. McKitrick has shown that this is so, and that there are a large number of gaps in the Russian records. Also, I showed that many of the boxes depended on a very small number of records, in some cases one or two.
It is scandalous that they are allowed to get away with using such defective records. I would like to see a study to identify worthless and defective records and eliminate them from the averages. The Americans (e.g. Vose and Menne Climate Research 2004 2961-2971) have established that you need at least 25 stations for a fair average. They also showed great variability in instrumentation and record keeping, even in the USA. The methods for "correcting" the data have never been fully revealed. The Sea Surface data have been shown to be defective by Christy, Parker et al Geophys Res Letters 2001 Vol 38 183-186, but nothing has been done to correct them.
It is time for a scientific assault on the supposed surface record. Actual visits to key stations with a study of history, records, technical expertise, and instrumentation is needed. Can you find some keen young students who could get a grant to do some of this?
With much encouragement