cc: Kevin Trenberth <trenbert@cgd.ucar.edu>, Caspar Ammann <ammann@ucar.edu>, rbradley@geo.umass.edu, tcrowley@duke.edu, mhughes@ltrr.arizona.edu, omichael@princeton.edu, t.osborn@uea.ac.uk, jto@u.arizona.edu, Scott Rutherford <srutherford@rwu.edu>, p.jones@uea.ac.uk, mann@virginia.edu
date: Mon, 13 Oct 2003 12:59:15 -0400
from: "Michael E. Mann" <mann@virginia.edu>
subject: Re: draft
to: Tom Wigley <wigley@ucar.edu>, Keith Briffa <k.briffa@uea.ac.uk>

   Thanks Tom,
   Working, at this very moment, on a way to broach the valid point raised by Keith w/out
   otherwise conflicting w/ what we say. I think some careful wording can accomplish this.
   More soon,
   mike
   At 10:37 AM 10/13/2003 -0600, Tom Wigley wrote:

     Folks,
     Keith makes a good point about the existence of the MWE. Its existence (or not) does not
     have any *direct* bearing on the reality of anthro warming. But one must be careful here
     not to appear to support the statement of S03 that we criticize at the start of our
     response.
     The past record *does* have a bearing on the confidence we place on anthro effects --
     since it is an important aspect of model validation. So the key word here is 'direct'.
     I suggest looking again at the start of our response to make sure the issue here is
     clear.
     Tom.
     ++++++++++++++++++++++++++++++++++==
     Keith Briffa wrote:

     Mike and all
     Hi , just back from a trip and only now catching up with important emails. Given
     the restricted time and space available to furnish a response to SB comments ,
     I offer the following mix of comment and specific wording changes:
     I agree that the S+B response is designed to deflect criticism by confusing the issues
     rather than answering our points.
     In fact they fail to address any of the 3 specific
     issues we raised Namely , 1. the need for critical evaluation of proxy inputs , 2. the
     need for a consistent assimilation of widespread (dated and well resolved ) records,
     3. the essential requirement for objective/quantitative calibration (scaling) of the
     input
     records to allow for assessment of the uncertainties when making
     comparisons of different reconstructions and when comparing early with recent
     temperatures.
      Their own , ill-conceived and largely subjective approach did not take
     account of the uncertainties and problems in the use of palaeodata that they chose to
     highlight in their opening remarks.
     I would be in favour of stating something to this effect at the outset of our response.
     Also , as regards the tree-ring bit , I fully concur with  the sense of your text as
     regards Section 1, but suggest the following wording (to replace ",rarely for annual
     ring widths, and almost entirely at higher latitudes.")
     "but in certain high-latitude regions only. Where this is the case , these relatively
     recent
     (ie post 1950) data are not used in calibrating temperature reconstructions. In many
     other
     (even high-latitude) areas  density or ring-width records display no bias."
     In the spirit of healthy debate - I agree with Tim's remarks , warning against
     presenting a too
     sanguine impression that the borehole debate is closed ( though I do think it is
     closing!).
     I also believe , as you already know, that the use of a recent padding algorithm to
     extend
     smoothed data to the present time, is inappropriate if it assumes the continuation of a
     recent
     trend. This is likely to confuse , rather than inform, the wider public about the
     current climate state .
     Finally , I repeat my earlier remarks (made before EOS piece published) that we are
     missing
     an opportunity to say that a warm Medieval period per se is not a refutation of
     anthropogenic
     warming , {as its absence is no proof}, if we do not understand the role of specific
     forcings (natural
     and anthropogenic) that influenced medieval and current climates.
     Cheers
     Keith
     At 12:48 PM 10/9/03 -0600, Kevin Trenberth wrote:

     Hi all
     Here are my suggested changes: toned down in several places.  Tracking turned on
     Kevin
     Michael E. Mann wrote:

     Dear co-authors,
     Attached is a draft response, incorporating suggestions Kevin, Tom W, and Michael.  I've
     aimed to be as brief as possible, but hard to go much lower than 750 words and still
     address all the key issues. 750 words, by the way, is our allotted limit.
     Looking forward to any comments. Feel free to send an edited version if you prefer, and
     I'll try to assimilate all of the suggested edits and suggestions into a single revised
     draft. If you can get comments to me within the next couple days, that would be very
     helpful as we're working on a late October deadline for the final version.
     Thanks for your continued help,
     mike
     ______________________________________________________________
                         Professor Michael E. Mann
                Department of Environmental Sciences, Clark Hall
                           University of Virginia
                          Charlottesville, VA 22903
     _______________________________________________________________________
     e-mail: <[1]mailto:mann@virginia.edu >mann@virginia.edu   Phone: (434) 924-7770   FAX:
     (434) 982-2137
              [2]http://www.evsc.virginia.edu/faculty/people/mann.shtml

     --
     ****************
     Kevin E. Trenberth                              e-mail:
     <[3]mailto:trenbert@ucar.edu>trenbert@ucar.edu
     Climate Analysis Section, NCAR
     <[4]http://www.cgd.ucar.edu/cas/>[5]www.cgd.ucar.edu/cas/
     P. O. Box 3000,                                 (303) 497 1318
     Boulder, CO 80307                               (303) 497 1333 (fax)
     Street address: 1850 Table Mesa Drive, Boulder, CO  80303

     -- Professor Keith Briffa,
     Climatic Research Unit
     University of East Anglia
     Norwich, NR4 7TJ, U.K.
     Phone: +44-1603-593909
     Fax: +44-1603-507784
     [6]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
            [7]http://www.evsc.virginia.edu/faculty/people/mann.shtml

