I appreciate it. The first link is coming up 404, but I'll check the other two. I think I'm superficially familiar with both, but I haven't actually read them in their entirety. Will do if I have time.
there is a substantial amount of overlap between these reconstructions and our actual instrumental record during the calibration period
From memory, I don't think this is quite the right conclusion. Rather, the instrumental record is used to calibrate the reconstruction, so the overlap approaches 100%. Worse, the accusations are that the correlation is even better because any trees not matching the temperature record have been eliminated as non-performing! I don't think either of these papers shows accuracy of reconstruction on an out-of-sample set for which there exists an outside measurement. I'll recheck, though.
None of this really changes what the comment says, which was basically "Don't use this to plot past 1960, because we know that part needs corrections".
I don't disagree here. In the absence of some overriding context, that seems like a valid reading of the comment.
Hmm, it looks like the first link got eaten by HN's linkerator due to the %27 (single quote) in the URL. Sorry about that, try http://preview.tinyurl.com/ydb8h28.
As for the calibration period, you're right, there are definitely some issues there, and that's a problem with the entire temperature reconstruction approach. We only have reliable instrumental records back to the middle of the 19th century, so it's hard to test any kind of reconstruction on a large scale.
Personally, I don't put much faith in the reconstructions themselves - I just think that it's important for people to understand the context around these experiments, since there's so much blatantly false information going around. It's hard enough for those of us who aren't climatologists to keep up with the information without people screaming bloody murder over a few lines of comments that they don't even understand.
there is a substantial amount of overlap between these reconstructions and our actual instrumental record during the calibration period
From memory, I don't think this is quite the right conclusion. Rather, the instrumental record is used to calibrate the reconstruction, so the overlap approaches 100%. Worse, the accusations are that the correlation is even better because any trees not matching the temperature record have been eliminated as non-performing! I don't think either of these papers shows accuracy of reconstruction on an out-of-sample set for which there exists an outside measurement. I'll recheck, though.
None of this really changes what the comment says, which was basically "Don't use this to plot past 1960, because we know that part needs corrections".
I don't disagree here. In the absence of some overriding context, that seems like a valid reading of the comment.