2002 Briffa email mentions Mann's "diminishing support" and the "questionable nature of much of Mann's verbiage"; says "Mike could be a lot more open about the real uncertainty of his early temperature estimates"

Email 2119

[Ed Cook] I agree with you that Mike seems to be overwhelmingly concerned about what the greenhouse sceptics might think. Frankly, I just ignore the bastards like John Daly. Mike should do the same.
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[Keith Briffa] My overall opinion is that you are just about right in balancing firm response to get the record straight with a need to keep composure and preserving the probability of continuing constructive interaction with Mann (and his diminishing support). Perhaps the one point I would make though, is that you underplay the questionable nature of much of Mann's verbiage ,in as much it is a response to imagined rather than real conflict between your Science paper and his reconstruction. Most of his comments I feel are addressing what he imagines (rightly or wrongly ) the greenhouse sceptics will say about recent warming after reading your paper , not what you actually say. His reiteration of the point that unprecedented change still stands is the primary example. You say temperatures about 1000 years ago "approach" those up to 1990. This is reasonable - and if the reader studies your two chronology comparison , it is clear that the MWP is not strongly hemispherically represented contemporaneously...Mike could be a lot
more open about the real uncertainty of his early temperature estimates