date: Wed Feb 15 16:43:41 2006 from: Keith Briffa subject: bullets to: jto@u.arizona.edu Peck do not think you will like what I say here , but I am going to give straight answers to your questions. First The new draft says enough in the text now about "far-less-accurately dated" and "low-resolution proxy records that can not be rigorously calibrated" in relation to this paper (Moberg et al.) . It is not appropriate to single the one series out for specific criticism in the summary . The use of the word "only" implies we do not believe it. Mike Mann's suggestion begs a lot of questions about what constitutes "significantly warmer". You need to have a Null Hypothesis to test . If you mean would the estimates in Moberg and the other reconstructions (during medieval time) show significantly different means using a t-test - then of course not , but this tells us nothing other than they are not likely samples from totally different populations - an almost impossible test to pass given the wide uncertainties on all reconstructions . Incidentally, we do not have formal (calibration ) uncertainties for Moberg anyway (just boot-strapped uncertainty on the average low-frequency curve). I think the vagueness is necessary - "suggests slightly" and is appropriate. I would not call out The results of Tim and my paper either. It is just an aside in the Medieval box at present , perhaps with a Figure to accompany the original if you agree, but without more text in the Chapter , which I do not consider appropriate, it should not be highlighted as a bullet. Second Simply make "1000" "1300 years. " and delete "and unusually warm compared with the last 2000 years." It is certainly NOT our job to be discussing attribution in the 20th century - this is Chapter 9 - and we had no room (or any published material) to allow a discussion of relative forcing contributions in earlier time. Therefore a vague statement about "perhaps due to solar forcing" seems unjustified. Third I suggest this should be Taken together , the sparse evidence of Southern Hemisphere temperatures prior to the period of instrumental records indicates that overall warming has occurred during the last 350 years, but the even fewer longer regional records indicate earlier periods that are as warm, or warmer than, 20th century means. Fourth fine , though perhaps "warmth" instead of "warming"? and need to see EMIC text Fifth suggest delete Sixth suggest delete Peck, you have to consider that since the TAR , there has been a lot of argument re "hockey stick" and the real independence of the inputs to most subsequent analyses is minimal. True, there have been many different techniques used to aggregate and scale data - but the efficacy of these is still far from established. We should be careful not to push the conclusions beyond what we can securely justify - and this is not much other than a confirmation of the general conclusions of the TAR . We must resist being pushed to present the results such that we will be accused of bias - hence no need to attack Moberg . Just need to show the "most likely"course of temperatures over the last 1300 years - which we do well I think. Strong confirmation of TAR is a good result, given that we discuss uncertainty and base it on more data. Let us not try to over egg the pudding. For what it worth , the above comments are my (honestly long considered) views - and I would not be happy to go further . Of course this discussion now needs to go to the wider Chapter authorship, but do not let Susan (or Mike) push you (us) beyond where we know is right. -- Professor Keith Briffa, Climatic Research Unit University of East Anglia Norwich, NR4 7TJ, U.K. Phone: +44-1603-593909 Fax: +44-1603-507784 [1]http://www.cru.uea.ac.uk/cru/people/briffa/