Michael Mann's hockey stick co-author Hughes: "all existing reconstructions of hemisphere-scale temperatures 1000 years ago (or even for all the first half of the second millennium AD) should be viewed as very preliminary"

Email 209

All of our attempts, so far, to estimate hemisphere-scale temperatures for the period around 1000 years ago are based on far fewer data than any of us would like. None of the datasets used so far has anything like the geographical distribution that experience with recent centuries indicates we need, and no-one has yet found a convincing way of validating the lower-frequency components of them against independent data. As Ed wrote, in the tree-ring records that form the backbone of most of the published estimates, the problem of poor replication near the beginnings of records is particularly acute, and ubiquitous. I would suggest that this problem probably cuts in closer to 1600 than 1400 in the several published series. Therefore, I accept that everything we are doing is preliminary, and should be treated with considerable caution.
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I hope it's clear from this that I don't disagree with the general proposition that all existing reconstructions of hemipsphere-scale temperatures 1000 years ago (or even for all the first half of the second millennium AD) should be viewed as very preliminary...
We all have a lot to do

Malcolm K. Hughes - Wikipedia, the free encyclopedia

In 1998, he was a co-author with Michael E. Mann and Raymond S. Bradley on a paper which later spurred the hockey stick controversy.

By the way, note this little nugget from Michael Mann, also in email 209:

OK--thanks for your response. I'll let Malcolm respond to the technical issues regarding RC. I'm not really qualified to do so myself anyway.