cc: "raymond s.bradley" <rbradley@geo.umass.edu>, mhughes@ltrr.arizona.edu, "Phil Jones" <p.jones@uea.ac.uk>, Scott Rutherford <srutherford@rwu.edu>
date: Thu, 30 Oct 2003 12:11:21 -0500
from: "Michael E. Mann" <mann@virginia.edu>
subject: Re: Can you believe it???
to: Keith Briffa <k.briffa@uea.ac.uk>, Tim Osborn <t.osborn@uea.ac.uk>

   Thanks Keith,
   I really appreciate your help.
   I'm happy for us to try to soften the tone, and will look forward to your suggested
   changes, etc. in this regard.
   I'm about 99% sure, at this point, that my facts are right though--look forward to hearing
   what you think I've reading through it--its dense, takes some effort to figure out what
   they eliminated. But they appear to have eliminated *just* the right series.. It really was
   a censoring of data as far as I can tell, key data...
   talk to you later,
   mike
   p.s. as for the target audience/date--I'll defer to you guys. I think, from Tim's comments,
   this has to go out quickly. We've got to nip this in the bud before it gets any more play.
   So I'm thinking, tomorrow at the latest.
   Target audience--i think the idea is the same huge email distribution/listserv that they
   sent their disinformation out to in the first place.
   At 04:50 PM 10/30/2003 +0000, Keith Briffa wrote:

     Mike and others
     I am sorry but been in a meeting all day - my first impression of reading the text is to
     caution against releasing this statement without more discussion. Do not be bounced into
     saying stuff you are not sure of , and using emotive language that smacks of too
     emotional a response . I am staying a while to read and comment in detail - and will try
     to fax something. Have to go soon because of daughter and need to write 2 PhD proposals
     tonight . Please clarify if there is a deadline that you are working too and what target
     is this piece aimed at.?
     Keith
     At 09:35 AM 10/30/03 -0500, Michael E. Mann wrote:

     Guys,
     I'm right, aren't I????
     mike
     At 02:13 PM 10/30/2003 +0000, Tim Osborn wrote:

     At 14:02 30/10/2003, you wrote:

     Guys, can you take a look at this.
     I think that everything I say here is true! But we've got to be sure.
     There are more technical things they did wrong that I want to add, but this is the
     critical bit--what do you think. Comments? Thanks...
     mike
     ________________________________________
     The recent paper by McIntyre and McKitrick (Energy and Environment, 14, 751-771) claims
     to be an "audit" of the analysis of Mann, Bradley and Hughes (1998) or "MBH98".  An
     audit involves a careful examination, using the same data and following the exact
     procedures used in the report or study being audited.  McIntyre and McKitrick ("MM")
     have done no such thing, having used neither the data nor the procedures of MBH98. Their
     analysis is notable only in how deeply they have misrepresented the data, methods, and
     results of MBH98. Journals that receive critical comments on a previously published
     papers always provide the authors who are being criticized an opportunity to review the
     study prior to publication, and offer them the chance to respond.  This is standard
     operating procedure in any legitimate peer-reviewed scientific journal. Mann and
     colleagues were never given this opportunity, nor were any other leading paleoclimate
     scientists that we're familiar with.  It is unfortunate that the profound errors, and
     false and misleading statements, and entirely spurious results provided in the  McIntyre
     and McKitrick article were ever allowed to see the light of day by those would have been
     able to detect them. . We suspect the extremely checkered history of "Energy and
     Environment" has some role to play in this. The authors should retract their article
     immediately, and issue a public apology to the climate research community for the
     injustice they have done in publishing and promoting this deeply deceptive and flawed
     analysis.
     Not only were critical errors made in their analysis that render it thoroughly invalid,
     but there appear to have been several strikingly subjective decisions made to remove key
     indicators of the original MBH98 network prior to AD 1600, with a dramatic impact on the
     resulting reconstruction.  It is precisely the over which the numerous indicators were
     removed (pre 1600 period) during which MM reconstruct anomalous warmth  that is in sharp
     opposition to the cold conditions observed in MBH98 and  nearly  all other independent
     published estimates that we know of.
     While the authors dutifully cite the small inconsistency between the number of proxy
     indicators reported by, and found in the public data archive, of Mann et al back in time
     (there indeed appear to have been some minor typos in the MBH98 paper), it is odd that
     they do not cite the number of indicators in their putative version of the Mann et al
     network based on the independent collection of data, back time. The reader is literally
     left to do a huge amount of detective work, based on the tables in their pages 20-23, to
     determine just what data have been eliminated from the original Mann et al network. It
     seems odd, indeed, that their "substitutions" of other versions (or in some case, only
     apparent, and not actual, versions) of proxy data series for those in the original Mann
     et al (1998) network has the selective effect of deleting key proxy indicators that
     contribute dramatic cooling during the 16th century, when the MM reconstruction shows an
     anomalous warming departure from the Mann et al (1998) and all other published Northern
     Hemisphere temperature reconstructions.
     Here are some blatant examples:
     1) The authors (see their Figure 4) substitute a younger version of one of the Jacoby et
     al Northern Treeline series for the older version used by MBH98. This substitution has
     effect of removing a predictor of 15th century cooling [Incidentally, MM make much of
     the tendency for some tree ring series, such as this one, to show an apparent cooling
     over the past couple decades. Scientists with expertise in dendroclimatology know that
     this behavior represents a  decrease in the sensitivity to temperature in recent decades
     that likely is related to conditions other than temperature which are limiting tree
     growth]
     2) The authors eliminate, without any justification, the entire dataset of 70 Western
     North American (WNA) tree-ring series available between 1400 and 1600 (this dataset is
     represented, by MBH98, in terms of a smaller number of representative Principal
     Component time series). The leading pattern of variance in this data set exhibits
     conditions from 1400-1800 that are dramatically colder than the mid and late 20th
     century, and a very prominent cooling in the 15th century in particular. The authors
     eliminated this entire dataset because they claimed that the underlying data was not
     available in the public domain.
     In point of fact, not only were the individual WNA data all available on the public ftp
     site provided by Mann and colleagues:
     [1]ftp://holocene.evsc.virginia.edu/pub/MBH98/TREE/ITRDB/NOAMER/, but they were also
     available, despite the claims to the contrary by MM, on NOAA's website as well:
     [2]ftp://ftp.ngdc.noaa.gov/paleo/treering/chronologies/northamerica/usa
     The deletion of this critical (see Mann et al, 1999) dataset appears to  one of the more
     important censorings performed by MM  that allows them to achieve their spurious result
     of apparent 15th-16th century warmth.
     We have not, as yet, finished determining just how many important indicators were subtly
     censored from the MBH98 dataset by the various subjective substitutions described on
     pages 20-23. However, given the relatively small number of indicators available between
     1400-1500 in the MBH98 network (22-24) and their elimination of some of the more
     critical ones, it would appear that this subjective censoring of data, alone, explains
     the spurious, misleading, and deceptive result achieved by the authors.
     Incidentally, MBH98 go to great depths to perform careful cross-validation experiments
     as a function of increasing sparseness of the candidate predictors back in time, to
     demonstrate statistically significant reconstructive skill even for their earlier
     (1400-1450) reconstruction interval. MM describe no cross-validation experiments. We
     wonder what the verification resolved variance is for their reconstruction based on
     their 1400-1450 available network, during the independent latter 19th century period?
     There are numerous other serious problems that would render the MM analysis completely
     invalid, even in the absence of the serious issue raised above, and these are detailed
     below
     .
     .
     .
     ______________________________________________________________
                         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
              [3]http://www.evsc.virginia.edu/faculty/people/mann.shtml

     Dr Timothy J Osborn
     Climatic Research Unit
     School of Environmental Sciences, University of East Anglia
     Norwich  NR4 7TJ, UK
     e-mail:   t.osborn@uea.ac.uk
     phone:    +44 1603 592089
     fax:      +44 1603 507784
     web:      [4]http://www.cru.uea.ac.uk/~timo/
     sunclock: [5]http://www.cru.uea.ac.uk/~timo/sunclock.htm

     ______________________________________________________________
                         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
              [6]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
     [7]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
            [8]http://www.evsc.virginia.edu/faculty/people/mann.shtml

