cc: p.jones@uea.ac.uk, t.osborn@uea.ac.uk date: Tue Jun 10 14:53:21 2003 from: Keith Briffa subject: Re: possible rewording of section of letter? to: "Michael E. Mann" thanks for that Mike - now the reference to "agree remarkably well with the proxy-based reconstructions (Figure 1) " [later part of paragraph ] . Unfortunately , the Bauer et al curve clearly does not - at least from AD 1100 to 1400! Again some qualify is needed - perhaps "for the most part , agree well " ? and later [middle of the 6th paragraph], "relative hemispheric warmth during the 10th to 12th centuries" is ambiguous and we prefer "relative hemispheric warmth during the 1oth,11th and 12th centuries" At 08:53 AM 6/10/03 -0400, Michael E. Mann wrote: Thanks Keith, I agree w/ you entirely, and the revised wording seems better indeed. It definitely has my blessing. Thanks for the help, mike p.s. I'm available through tomorrow morning in case there are any other important last-minute issues that arise At 01:15 PM 6/10/2003 +0100, Keith Briffa wrote: Mike I know you up to your neck in marital bliss , and I am sorry to bother you , but on the advice of Phil I thought it worth asking for your sanction of the following rewording of the end of the penultimate paragraph of the letter. This is, we believe, important because the original phrasing is a large hostage to fortune, given that it seems to criticise (completely rubbish might be a better phrase) all work based on proxies that do not actually resolve the "climate trends of the last few decades" . As you know, many proxies used by you , us, and others, do not extend over this period of rapid warming and some that do (eg our MXD data) do not display an appropriate rapid response. What you have written could coneivably be twisted to imply that we (you) are criticising our (your) own work. How about changing the section with currently reads - The conclusions , for example, of the ....of temperatures during the most recent decades against reconstructions of past temperatures, taking into account the uncertainties in those reconstructions. As it is only the past few decades during which Northern Hemisphere temperatures have exceeded the bounds of natural variability, any analysis (SB03) that considers simply '20th century' mean conditions , or does not properly resolve the changes of the late 20th century (e.g. through the interpretation of evidence from proxy indicators which do not resolve the climate trends of the past few decades), cannot yield any insight into whether or not recent warming is anomalous in a long-term and large-scale context. to - The conclusions , for example, of the ....of temperatures during the late 20th century against reconstructions of past temperatures, taking into account the uncertainties in those reconstructions. As it is only the past few decades during which Northern Hemisphere temperatures have exceeded the bounds of natural variability, any analysis (SB03) that considers simply '20th century' mean conditions, or interprets past temperatures using the evidence from proxy indicators not capable of resolving decadal-timescale trends, can provide only very limited insight at best into whether or not recent warming is anomalous in a long-term and large-scale context. -- 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/ ______________________________________________________________ Professor Michael E. Mann Department of Environmental Sciences, Clark Hall University of Virginia Charlottesville, VA 22903 _______________________________________________________________________ e-mail: mann@virginia.edu Phone: (434) 924-7770 FAX: (434) 982-2137 [2]http://www.evsc.virginia.edu/faculty/people/mann.shtml -- 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[4]/