Taken by Storm
No average temperature
In their own briefing, the book's authors say:
- In the absence of physical guidance, any rule for averaging temperature is as good as any other. The folks who do the averaging happen to use the arithmetic mean over the field with specific sets of weights, rather than, say, the geometric mean or any other. But this is mere convention. 
This is false. If you connect two systems of different temperatures with a conductor, the temperatures of both systems will reach an equilibrium which is a weighted arithmetic mean. For example, imagine mixing a bucket of cold water and a bucket of warm water. The result will have the temperature of the weighted arithmetic mean of the two bucket's temperatures. This is why everyone uses the weighted arithmetic mean.
They go on to argue that if a geometric mean is used instead of an arithmetic one, a trend of global warming changes to a trend of global cooling. But Tim Lambert discovered that this was because they inconsistently treated missing data between the two calculations. When the missing data is corrected, both means show the same result: neither cooling nor warming.
When confronted, McKitrick claimed this helped his argument because it showed there were even more ways to calculate average temperature.
- Christopher Essex and Ross McKitrick, "Taken By Storm: The Troubled Science, Policy and Politics of Global Warming", Key Porter Books; May 2003. ISBN 1552632121