Thursday, December 22, 2011


From: "Michael E. Mann" <>
To: Tom Crowley <>
Subject: Re: not so fast
Date: Tue, 02 Jan 2007 11:18:45 -0500
Cc: "raymond s. bradley" <>,, Eric Steig <>,,,, Caspar Ammann <>, William Connelley <>,,,

for those who are interested, there is a paper by Goosse et al (I'm a co-author) explaining
why parts of Europe such as central england would have experienced warmer summer conditions
relative to present than other regions, related to early land-use change:
Goosse, H., Arzel, O., Luterbacher, J., Mann, M.E., Renssen, H., Riedwyl, N., Timmermann,
A., Xoplaki, E., Wanner, H., [1]The origin of the European "Medieval Warm Period", Climate
of the Past, 2, 99-113, 2006.
paper available as pdf here:
meanwhile, winter warmth could have been due to a strong AO/NAO pattern associated with
decreased volcanism and high solar, as discussed in the various Shindell et al paper.
this simply underscores the point that we all often make, that one needs to take into
account regional factors when interpreting regional records. This is especially relevant to
the extrapolation of a long record from England to the entire NH (which appears to have
been tacitly done by Jack Eddy?),
Tom Crowley wrote:

we still don't have an adequat explanation as to how Jack "cooked up" that figure - I do
not believe it was purely out of thin air - look at the attached - which I used in the
Crowley-Lowery composite just because it was "out there" - I made no claim that it was the
record of record, but just that it had been used beforer. the Lamb ref. is his book dated
1966. I will have to dig up the page ref later. Dansgaard et al. 1975 Nature paper on
Norsemen...etc used that figure when comparing what must have been their Camp Century
record - have to check that too - where the main point of that paper was that the timing of
Medieval warmth was different in Greenlandn and England!
25 years later my provocation for writing the CL paper came from a strong statement on the
MWP by Claus Hammer that the canonical idea of the MWP being warming than the present was
correct and that the 1999 Mann et al was wrong. he kept going on like that I reminded him
that he was a co-author on the 1975 paper! that is also what motivated to do my "bonehead"
sampling of whatever was out there just to see what happened when you added them all
together - the amazing result was that it looked pretty much like Mann et al. ther rest is
history -- much ignored and forgotten.
I might also pointn out that in a 1996 Consequences article I wrote - and that Fred Singer
loves to cite -- Jack (who was the editor of the journal) basically shoehorned me into
re-reproducing that figure even though I didn't like it - there was not an alternative. in
the figure caption it has a similar one to Zielinski except that it states "compiled by
R.S. Bradley and J.A. Eddy based on J.T. that puts a further twist on this
because it point to Houghton not Bradley/Eddy as the source. Jack must have written that
part of the figure caption because I don't think I knew those details.
but we still don't know where the details of the figure came from - the MWP is clearly more
schematic than the LIA (actually the detailsl about timing of the samll wiggles in the LIA
are pretty good) - maybe there was a meshing of the Greenland and the England records to do
the MWP part - note that the English part gets cooler. they may also have thrown in the
old LaMarche record - which I also have. maybe I can schlep something together using only
those old three records.
Michael E. Mann wrote:

Ray, happy holidays and thanks for the (quite fascinating) background on this. It would be
good material for a Realclimate article. would be even better if someone could get Chris on
record confirming that this is indeed the history of this graphic...
raymond s. bradley wrote:

I believe this graph originated in a (literally) grey piece of literature that Jack Eddy
used to publish called "Earth Quest". It was designed for, and distributed to, high
school teachers. In one issue, he had a fold-out that showed different timelines,
Cenozoic, Quaternary, last 100ka, Holocene, last millennium, last century etc. The idea
was to give non-specialists a perspective on the earth's climate history. I think this
idea evolved from the old NRC publication edited by L. Gates, then further elaborated on
by Tom Webb in the book I edited for UCAR, Global Changes of the Past. (This was an
outcome of the wonderful Snowmass meeting Jack master-minded around 1990).

I may have inadvertently had a hand in this millennium graph! I recall getting a fax
from Jack with a hand-drawn graph, that he asked me to review. Where he got his version
from, I don't know. I think I scribbled out part of the line and amended it in some
way, but have no recollection of exactly what I did to it. And whether he edited it
further, I don't know. But as it was purely schematic (& appears to go through ~1950)
perhaps it's not so bad. I note, however, that in the more colourful version of the
much embellished graph that Stefan circulated ([3]
the end-point has been changed to 2000, which puts quite a different spin on things.
They also seem to have fabricated a scale for the purported temperature changes. In any
case, the graph has no objective basis whatsoever; it is purely a "visual guess" at what
happened, like something we might sketch on a napkin at a party for some overly
persistent inquisitor..... (so make sure you don't leave such things on the table...).
What made the last millennium graph famous (notorious!) was that Chris Folland must have
seen it and reproduced it in the 1995 IPCC chapter he was editing. I don't think he
gave a citation and it thus appeared to have the imprimatur of the IPCC. Having
submitted a great deal of text for that chapter, I remember being really pissed off that
Chris essentially ignored all the input, and wrote his own version of the paleoclimate
record in that volume.

There are other examples of how Jack Eddy's grey literature publication was misused. In
a paper in Science by Zielinski et al. (1994) [v.264, p.448-452]--attached-- they
reproduced [in Figure 1c] a similarly schematic version of Holocene temperatures giving
the following citation, "Taken from J. A. Eddy and R. S. Bradley, Earth-quest 5 (insert)
(1991), as modified from J. T. Houghton, G. J. Jenkins, J. J. Ephraums, Climate Change,
The IPCC Scientific Assessment (Cambridge Univ. Press, Cambridge, 1990)."
But I had nothing to do with that one!
So, that's how a crude fax from Jack Eddy became the definitive IPCC record on the last
Happy New Year to everyone

Raymond S. Bradley
Director, Climate System Research Center*
Department of Geosciences, University of Massachusetts
Morrill Science Center
611 North Pleasant Street
AMHERST, MA 01003-9297
Tel: 413-545-2120
Fax: 413-545-1200
*Climate System Research Center: 413-545-0659
Paleoclimatology Book Web Site: [5]
Publications (download .pdf files):

Michael E. Mann
Associate Professor
Director, Earth System Science Center (ESSC)

Department of Meteorology Phone: (814) 863-4075
503 Walker Building FAX: (814) 865-3663
The Pennsylvania State University email: [7]
University Park, PA 16802-5013


Michael E. Mann
Associate Professor
Director, Earth System Science Center (ESSC)

Department of Meteorology Phone: (814) 863-4075
503 Walker Building FAX: (814) 865-3663
The Pennsylvania State University email: [9]
University Park, PA 16802-5013



1. file://localhost/tmp/Goosseetal-CP06.pdf

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