Sunday, June 10, 2012

5059.txt

cc: Gavin Schmidt <gschmidtatXYZxyzs.nasa.gov>
date: Wed Sep 30 17:08:02 2009
from: Tim Osborn <t.osbornatXYZxyz.ac.uk>
subject: Re: attacks against Keith
to: Michael Mann <mannatXYZxyzeo.psu.edu>, Phil Jones <p.jonesatXYZxyz.ac.uk>

At 16:06 30/09/2009, Michael Mann wrote:

And Osborn and Briffa '06 is also immune to this issue, as it eliminated any combination
of up to 3 of the proxies and showed the result was essentially the same (fair to say
this Tim?).

Mike,
figs S4-S6 in our supplementary information show results leaving out individual, groups of
two, and groups of three proxies, respectively. It's attached.
I wouldn't say we were immune to the issue -- results are similar for these leave 1, 2 or 3
out cases, but they certainly are not as strong as the case with all 14 proxies. Certainly
in figure S6, there are some cases with 3 omitted (i.e. some sets of 11) where modern
results are comparable with intermittent periods between 800 and 1100. Plus there is the
additional uncertainty discussed on the final page of the supplementary information in the
link between the proxy records and the instrumental temperatures (remember we have no
formal calibration, we're just counting proxies [ I'm still amazed that Science agreed to
publish something where the main analysis only involves counting from 1 to 14! :-) ])

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