UPDATE: 12:55PM Dr. Mann ducks a TV station reporter who requested an interview afterwards, see below.
Steve McIntyre recently published a new graph on his website Climate Audit.
Alerted to the fact that Dr. Mann would be speaking at the OC Water Summit, I was asked to submit a question, but I could not make it there in time given the short notice. A suitable proxy, our friend Roger Sowell, was kind enough to attend and ask a question. Here’s what I sent him in way of a primer, I don’t know the actual question he asked, but we hope to have a video presentation later as I was told it was recorded.

Figure 1. Yamal Chronologies. Green – from Hantemirov _liv.rwl dataset; red- from Briffa et al 2008.
How interesting it is that the Hantemirov data in green, diverges from the CRU 2008 “Hockey Team” data in red. This is due to a larger data sample. One tree core, YAD061 is responsible for most of the difference, when a small set of tree core data is used.
This graph demonstrates how trees simply don’t show a hockey stick shape when all of the data is used.
In MBH98, your paper Dr. Mann, has a similar problem to the Briffa data. Your solution was to not use tree core data after 1960 and to splice on the instrumental temperature record to in effect “hide the decline” of the trees after 1960.
How do you respond to the charge that the tree ring data was cherry picked to show a desired result, and that Mr. McIntyre has falsified your work by showing that the premise of a hockey stick falls apart when all of the data is used?
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Roger Sowell was in the audience this morning (thank you for responding on short notice). I received this answer via text from Roger Sowell, to a question he asked: Continue reading →