"The data are attached to this e-mail. They go from 1402 to 1995, although we usually stop the series in 1960 because of the recent non-temperature signal that is superimposed on the tree-ring data that we use. "
So who of the discussing people is well versed enough in tree-ring data to have an informed opinion on this? It sounds as if in recent times tree-ring data has to be read differently (which seems possible, other factors could affect growth, don't know).
"1) The appropriateness of the statistical analyses employed 2) The reliance on the same small datasets in these multiple studies 3) The concept of "teleconnection" by which certain trees respond to the "Global Temperature Field", rather than local climate 4) The assumption that tree ring width and density are related to temperature in a linear manner.
Whilst I would not describe myself as an expert statistician, I do use inferential statistics routinely for both research and teaching and find difficulty in understanding the statistical rationale in these papers. As a plant physiologist I can say without hesitation that points 3 and 4 do not agree with the accepted science."
See link for full email thread: http://www.eastangliaemails.com/emails.php?eid=1064&file...
"I really wish I could be more positive about the Kyrgyzstan material, but I swear I pulled every trick out of my sleeve trying to milk something out of that. It was pretty funny though - I told Malcolm what you said about my possibly being too Graybill-like in evaluating the response functions - he laughed and said that's what he thought at first also. The data's tempting but there's too much variation even within stands. I don't think it'd be productive to try and juggle the chronology statistics any more than I already have - they just are what they are (that does sound Graybillian). I think I'll have to look for an option where I can let this little story go as it is.
Not having seen the sites I can only speculate, but I'd be optimistic if someone could get back there and spend more time collecting samples, particularly at the upper elevations.
Yeah, I doubt I'll be over your way anytime soon. Too bad, I'd like to get together with you and Ed for a beer or two. Probably someday though.
Cheers, Gary Gary Funkhouser Lab. of Tree-Ring Research The University of Arizona"
http://www.eastangliaemails.com/emails.php?eid=12&filena...
There really does need to be a full and detailed explanation of all this, immediately.
Anyway, you know what: people believe what they want to believe. This discussion is completely pointless.
Briffa, K.R., Schweingruber, F.H., Jones, P.D., Osborn, T.J., Shiyatov, S.G. and Vaganov, E.A., 1998 "Reduced sensitivity of recent tree growth to temperature at high northern latitudes." Nature 391, 678-682 (R)
Basically, since tree-ring density is influenced by temperature, you can use it to reconstruct temperatures. I believe the data set in question uses maximum latewood density (MXD), which accorded well with instrumental temperature readings until 1960, at which point they begin to show a decline in temperature while thermometers show an increase. The proposed solution is simply: Don't use the reconstructed temperatures after 1960, since they're wrong.
Doesn't this also imply that looking backward tree rings might be untrustworthy any earlier than some starting date? That in fact tree rings might work for a while, then vary for a while, then work again? How can anybody honestly claim that SOME tree ring evidence is usable and SOME is not -- and they know exactly which is which?
My bet would be the thermometers are wrong and the tree rings right. See, e.g.,
As for trusting tree ring data, this is an entirely different issue from this "Climate Gate" affair. That was, btw., an internal email, so nobody was supposed to trust anything. It was scientists exchanging some data. Surely it is allowed to LOOK at tree ring data.
These scientists are asking us to trust their thermometer readings alone, starting at exactly the date when tree rings began disagree with their hypothesis. We need a very very good explanation for this incredible coincidence.
There, that wasn't so hard, was it?