date: Fri Mar 3 16:57:36 2006 from: Keith Briffa subject: Re: photographs and other visuals for Science to: Jonathan Overpeck Peck we do need to say something , but as I said in an earlier message , not without more consideration. We should not write something curt on this - ditto the Co2 possible fertilisation . In the push to do all this other stuff , we have had to leave it - to discuss later how to include an uncertainty issues bit about recent environmental mess ups . The D'arrigo paper is not convincing , but we have to do some work to show why , instead of just saying this . The divergence issue is NOT universal , and not unrelated to very recent period bias arising from processing methods . It is VERY LIKELY not the threshold problem D'Arrigo thinks it is. We need money here to work on this and losing our last application to Europe has messed us up. For now we can not include anything. I will work on text for the next iteration. At 16:05 03/03/2006, you wrote: Hi Richard - this issue is one that we refer to in our key uncertainty table. I believe Keith Briffa was one of the first to write about it, and it is an important issue. I haven't seen R's paper or results myself, but I bet Keith has. I'm cc'ing this to him to see what he thinks. thanks, peck Know anything about the "divergence problem" in tree rings? R D'arrigo talked to the NRC yesterday. I didn't get to talk to her afterward, but it looked to me that they have redrilled a bunch of the high-latitude tree rings that underlie almost all of the high-res reconstructions, and the tree rings are simply missing the post-1970s warming, with reasonably high confidence. She didn't seem too worried, but she apparently has a paper just out in JGR. It looked to me like she had pretty well killed the hockey stick in public forum--they go out and look for the most-sensitive trees at the edge of the treeline, flying over lots and lots of trees that are lesss sensitive but quite nearby, and when things get a little warmer, the most-sensitive trees aren't anymore, and so the trees miss the extreme warming of the recent times, and can't reliably be counted as catching the extreme warmth of the MWP if there was extreme warmth then. Because as far as I can tell the hockey stick really was a tree-ring record, regardless of how it was labelled as multiproxy, this looks to me to be a really big deal. And, a big deal that may bite your chapter... --Richard -- Jonathan T. Overpeck Director, Institute for the Study of Planet Earth Professor, Department of Geosciences Professor, Department of Atmospheric Sciences Mail and Fedex Address: Institute for the Study of Planet Earth 715 N. Park Ave. 2nd Floor University of Arizona Tucson, AZ 85721 direct tel: +1 520 622-9065 fax: +1 520 792-8795 [1]http://www.geo.arizona.edu/ [2]http://www.ispe.arizona.edu/ -- Professor Keith Briffa, Climatic Research Unit University of East Anglia Norwich, NR4 7TJ, U.K. Phone: +44-1603-593909 Fax: +44-1603-507784 [3]http://www.cru.uea.ac.uk/cru/people/briffa/