Memorandum submitted by Stephen McIntyre
1. Reconstructions of temperature over the
past 1,000 years have been an highly visible part of IPCC presentations
to the public. CRU has been extremely influential in IPCC reconstructions
through: coauthorship, the use of CRU chronologies, peer review
and IPCC participation. To my knowledge, there are no 1000-year
reconstructions which are truly "independent" of CRU
influence. In my opinion, CRU has manipulated and/or withheld
data with an effect on the research record. The manipulation includes
(but is not limited to) arbitrary adjustment ("bodging"),
cherry picking and deletion of adverse data. The problem is deeply
rooted in the sense that some forms of data manipulation and withholding
are so embedded that the practitioners and peer reviewers in the
specialty seem either to no longer notice or are unoffended by
the practices. Specialists have fiercely resisted efforts by outside
statisticians questioning these practicesthe resistance
being evident in the Climategate letters. These letters are rich
in detail of individual incidents. My submission today will not
comment on these individual incidents (some of which I've commented
on already at Climate Audit), but to try to place the incidents
into context and show why they matter to the research record.
I will not comment in this submission on CRUTEM issues only for
2. Together with Ross McKitrick, I have
published several peer-reviewed articles on 1,000-year reconstructions
and reconstructions, made invited presentations to a panel of
the U.S. National Academy of Sciences, to a subcommittee of the
U.S. House Energy and Commerce Committee and a Union Session of
the American Geophysical Union and have in-depth personal knowledge
of CRU proxy reconstructions. I was a reviewer of the IPCC 2007
Assessment Report. I am the "editor" of a prominent
climate blog, www.climateaudit.org, which analyzes proxy reconstructions.
I am discussed in many Climategate Letters.
3. Keith Briffa was Lead Author of the IPCC
2007 section on "recent" paleoclimatology, the Climategate
Letters showing that he worked closely with Mann associate, Eugene
Wahl (not a listed IPCC expert reviewer). Mann was Lead Author
of the corresponding IPCC 2001 section, with the Climategate Letters
showing that he worked closely with Briffa and Jones.
4. Jones, Briffa and Osborn were on the
editorial boards of multiple climate journals and participated
actively both in peer review and the assignment of peer reviewers.
5. CRU scientists (and Climategate correspondent
Michael Mann) were coauthors of all three reconstructions in the
IPCC 2001 report and coauthors of six (of ten) multiproxy reconstructions
in the IPCC 2007 report.
6. CRU tree ring proxies (in particular,
Tornetrask, Yamal/Polar Urals, Taymir) were used in all 10 IPCC
2007 multiproxy reconstructions.
7. One of the underlying problems in trying
to use tree ring width/density chronologies for temperature reconstructions
is a decline in 20th century values at many sitesBriffa's
1992 density (MXD) chronology for the influential Tornetrask site
is shown at left below. The MXD chronology had a very high correlation
to temperature, but went down in the 20th century relative to
what it was "expected" to do and relative to the ring
width (RW) chronology (which had a lower correlation to temperature.)
So Briffa "adjusted" the MXD chronology, by a linear
increase to the latter values (middle), thereby reducing the medieval-modern
differential. This adjustment was described in private as the
"Briffa bodge" (Melvin and Briffa 2008).
LeftMXD chronology. Middle"Briffa
bodge". RightBriffa 1992 "adjusted".
8. Although there was no scientific basis
for such an arbitrary adjustment, peer reviewers of Briffa et
al (1992) did not object. "Bodging" then seems to
entered into the CRU toolkit to get reconstructions to "look"
right, as evidenced by the Climategate documents containing annotations
that the method contains "fudge factors" or "very
artificial corrections for decline" (eg http://di2.nu/foia/harris-tree/briffa_sep98_e.pro)
;****** APPLIES A VERY ARTIFICIAL CORRECTION FOR
2.6,2.6,2.6]*0.75 ; fudge factor
9. Although the bodge was reported in the original
article, the bodge was not reported in the numerous multiproxy
studies relying on the Tornetrask reconstruction nor in the IPCC
reports nor was it considered in calculation of confidence intervals.
10. There are many incidents in the Climategate
Letters of withholding data. I'll review one incident which, in
my opinion, has a direct impact on the research record.
11. Briffa et al (1995) produced
an influential chronology from the Polar Urals site (Figure 2left),
which combated the idea of a widespread Medieval Warm Period,
supposedly showing a very cold 11th century in Siberia, with 1032
supposedly being the coldest year of the millennium. Further measurements
(Figure 2right) yielded a chronology in which the 11th
century was warmer than the 20th century. Neither CRU nor any
other climate scientist ever published this update. The data at
right has never been publicly archived and was obtained only through
quasi-litigation at Science. (One of the Climategate Letters
expresses regret that the data was made available.)
URALS TREE RING CHRONOLOGIES
Left Briffa (1995). Rightupdated Polar
Urals version used in Esper et al (2002).
12. The failure to publish this data set
has two important adverse results. The inconsistency between different
tree ring chronologies is disguised. In addition, the data set
was unavailable for third parties interested in producing multiproxy
13. There has been considerable suspicion
that CRU cherry-picked the Yamal chronology over the updated Polar
Urals chronology or a still unavailable combined chronology attested
in Climategate Letter 1146252894.txt.
14. Instead of showing the updated Polar
Urals chronology (Figure 3left), Briffa (2000) replaced
it without discussion with a chronology from nearby Yamal, one
with an extremely pronounced hockey stick shape. This chronology
became a mainstay of subsequent multiproxy reconstructions, while
the unpublished Polar Urals chronology was ignored. Measurement
data for the three Briffa (2000) chronologiesYamal, Taymir
and Tornetraskwas not archived at the international tree
ring measurement archive. Briffa resisted requests to archive
the measurement data, which was not archived until September 2009
(and then only after Phil Trans B was asked to require its archiving.)
URALS TREE RING CHRONOLOGIES
Leftupdated Polar Urals version used in Esper
et al (2002). RightYamal from Briffa (2000).
15. Replacement of the Yamal chronology
with the Polar Urals chronology alters the ranking of the medieval
and modern periods in, for example, the Briffa (2000) composite
reconstruction, impacting IPCC assertions in respect to the confidence
of their belief in unprecedented modern warmth. As an IPCC reviewer,
I requested that this be disclosed. In his capacity as IPCC Lead
Author, Briffa refused. In the absence of any explanation of the
substitution, there is reason to be concerned about the reasons
for using one series rather than the other.
16. The Yamal chronology was very much in
the news just before Climategate broke, with questions being asked
at Climate Audit about replication and homogeneity, neither of
which had been previously addressed in peer reviewed literature.
17. The Climategate Letters (eg 878654527.txt)
also show evidence that Briffa's concern over non-linear recent
growtha concern that was not disclosed in Briffa (2000).
18. A similar cherry-picking issue arises
with the preferential use in multiproxy studies of the Briffa
(2000) Tornetrask version in preference to the Grudd (2006) version,
which has a medieval period that is relatively "warmer"
than the modern period.
LeftGrudd 2006, 2008; Right Briffa
19. The above examples show influential
CRU site chronologies. However, the number of proxies in a typical
IPCC multiproxy reconstruction is sufficiently small that the
choice between two versions of a single site chronology can impact
the overall reconstruction. For example, Figure 5 compares the
published Briffa (2000) reconstruction (left) with a version derived
merely by substituting the Polar Urals update for Yamal(right).
The medieval-modern differential changes with one seemingly inconsequential
change of version.
Leftversion from Briffa (2000); Rightvarying
the Tornetrask and Urals versions to newer versions.
... TO HIDE
20. Climate scientists have argued that
the term "trick" can denote a clever way "to bring
two or more different kinds of data sets together in a legitimate
fashion by a technique that has been reviewed by a broad array
of peers in the field." (Penn State Inquiry). This is incorrect
as applied to representations of the Briffa MXD reconstruction.
21. The "trick" arose in the context
of pressure on IPCC 2001 authors to present a "nice tidy
story" and to avoid a situation where the Briffa reconstruction
"diluted the message" (see http://climateaudit.org/2009/12/10/ipcc-and-the-trick/).
Two different variants of the "trick" appear in contemporary
22. Figure 6 (left) shows the actual Briffa
MXD reconstruction (data available for the first time in the Climategate
Letters) and (right) the version in IPCC 2001 Fig 2-21 (digitized
on right. The IPCC "trick" was not a "clever"
mathematical methodit was merely the deletion of inconvenient
data after 1960. Post-1960 values were even deleted in the reconstruction
archived version at NOAA.
LeftBriffa MXD reconstruction re-scaled to
IPCC scale with 40-point Hamming filter smooth. RightDigitized
from IPCC 2001 graphic.
23. The deletion of post-1960 values of
the Briffa MXD reconstruction gave the IPCC (2001) temperature
reconstructions a rhetorical appearance of consistency that did
not exist in the underlying data (as shown below).
24. A somewhat different "trick"
was used in the World Meteorological Organization 1999 report
(shown in Figure 8 below). Jones substituted instrumental temperatures
for MXD reconstruction values after 1960, resulting in an entirely
false rhetorical impression of the efficacy of tree ring reconstructions.
Far from this technique being "legitimate", Mann himself
had stated precisely the opposite about the splicing of temperatures
and reconstructions into a single graft:
No researchers in this field have ever, to our
knowledge, "grafted the thermometer record onto" any
reconstruction. It is somewhat disappointing to find this specious
claim (which we usually find originating from industry-funded
climate disinformation websites) appearing in this forum.
25. The Climategate Letters obviously contain
many dispiriting examples of poor conduct, including the following.
26. Withholding of data from potential critics:
Jones: We have 25 or so years invested in the
work. Why should I make the data available to you, when your aim
is to try and find something wrong with it.
Osborn to Science: I don't have any core measurement
data and therefore have none to give out!
[Climategate Letters and documents show that CRU had the requested
Mann to Osborn: I'm providing these [MBH residuals]
for your own personal use, since you're a trusted colleague. So
please don't pass this along to others without checking w/ me
first. This is the sort of "dirty laundry" one doesn't
want to fall into the hands of those who might potentially try
to distort things.
27. Use of the peer review process to suppress
or delay adverse publications:
If published as is, this paper could really do
some damage. It is also an ugly paper to review because it is
rather mathematical, with a lot of Box-Jenkins stuff in it. It
won't be easy to dismiss out of hand as the math appears to be
Recently rejected two papers (one for JGR and
for GRL) from people saying CRU has it wrong over Siberia. Went
to town in both reviews, hopefully successfully. If either appears
I will be very surprised.
I am really sorry but I have to nag about that
reviewConfidentially I now need a hard and if required
extensive case for rejecting.
I can't see either of these papers being in the
next IPCC report. Kevin [Trenberth] and I will keep them out somehoweven
if we have to redefine what the peer-review literature is!
28. Soft reviews of submissions by close
associates. The Climategate documents provide multiple examples
of soft reviews of submissions by colleagues Mann,
and Wahl and Ammann.
Presumably there are many others. The review of articles in which
a reviewer has a personal relationship is a recognized conflict
of interest in medical journals. For example, the World Associate
of Medical Editors statement
a reviewer may have difficulty providing an unbiased
review of articles by investigators who have been working colleagues.
Similarly, he or she may find it difficult to be unbiased when
reviewing the work of competitors
29. The Climategate Letters are replete
with examples of unprofessional language, which on occasion rises
The important thing is to deny that this has
any intellectual credibility whatsoever and, if contacted by any
media, to dismiss this for the stunt that it is.
If *others* want to say that their actions represent
scientific fraud, intellectual dishonesty, etc. (as I think we
all suspect they do), lets let *them* make these charges for us!
some cool statement can be made saying we believe
the "prats have really fucked up someway"and
that the premature publication of their paper is reprehensible.
I'm saddened to hear that this bozo is bothering
you too, in addition to NCAR, NSF, NAS, IPCC and everyone else.
Rest assured that I won't ever respond to McIntyre should he ever
contact me, but I will forward you any email he sends related
to this. I assume Scott feels the same way ...
personally, I don't see why you should make any
concessions for this moron.
Mr Fraudit never goes away does he? How often
has he been told that we don't have permission? Ho hum. Oh, I
heard that fraudit's Santer et al comment got rejected. That'll
brighten your day at least a teensy bit?
I noticed that ClimateFraudit had renewed their
interest in you. I was thinking about sending an email of sympathy,
but I was busy preparing for a quick trip to Hawaii:
I would immediately delete anything you receive
from this fraud.
Hi Andy, The McIntyre and McKitrick paper is
pure scientific fraud.
I've seen this junk already. Look at the co-authors!
DeFrietas, Bob Carter: a couple of frauds.
30. One of the most dispiriting aspects
of the Climategate Letters is the evidence of CRU's contribution
to the poisoned atmosphere of present climate science. In 2003,
CRU criticized us for supposedly not attempting to reconcile differences
between our methodology and Mann's methodology. In October 2003,
The single worst thing about the whole M&M
saga is not that they did their study, not that they did things
wrong (deliberately or by accident), but that neither they nor
the journal took the necessary step of investigating whether the
difference between their results and yours could be explained
simply by some error or set of errors in their use of the data
or in their implementation of your method.
31. Osborn proposed a draft statement, which,
had it been accepted by CRU, would probably have prevented much,
if not most, of the following controversy:
... we are withholding further comments until
we canby collaboration with M&M if possiblebe
certain of exactly what changes to data and method were made by
M&M, whether these changes can really explain the differences
in the results, and eventually which (if any) of these changes
can be justified as equally valid (given the various uncertainties
that exist) and which are simply errors that invalidate their
32. In November 2003, I entered into negotiations
with CRU, agreeing to their review of our pending follow-up to
our 2003 article, on the condition that CRU agreed to issue a
short statement if their review confirmed that we had raised valid
If you identify any flaws in our document, we
will rectify them, and you are at liberty to hold us to public
account if we fail to do so ...
If you find our document raises valid and meritorious
concerns, you will give us a short statement to that effect which
we are entitled to publish.
33. In a follow-up email, I re-assured CRU
that I did not have the faintest interest in publishing results
that were at cross-purposes.
We have entered into discussions about a possible
review by UEA/CRU in complete good faith. We do not have
the slightest interest in presenting incorrect or defective results
or to create debate which is merely at cross-purposes.
34. CRU then refused to carry out the review,
choosing to attempt to frustrate us in secret behind the scenes.
Jones, as a member of the editorial board of Climatic Change,
actively lobbied so that Mann would not be required to disclose
source code and supporting data that would have enabled us to
reconcile results. Despite his adverse interest, Jones appears
(according to a Climategate Letter) to have acted as a reviewer
of our 2004 submission to Nature, intervening not to ensure the
reconciliation of results proposed by Osborn, but to frustrate
any criticism of the Mann reconstruction.
K R, 2000. Quaternary Science Reviews, 19(1-5), 87-105.
Briffa, K R et al, 1992. Climate Dynamics,
Briffa, K R et al, 1995. Nature, 376(6536),
Briffa, K R et al, 2001. Journal of Geophysical
Research, 106(D3), 2929-2941.
Grudd, H, 2006. PhD Thesis, Stockholm University,
Faculty of Science.
Grudd, H, 2008. Climate Dynamics, (DOI 10.1007/s00382-007-0358-2).
International Panel on Climate Change, 2001. Climate
Change 2001: The Scientific Basis.
International Panel on Climate Change, 2007. Climate
Change 2007: The Physical Basis.
Mann, M E, Bradley, R S & Hughes, M K, 1998.
Nature, 392, 779-787.
Melvin, T and K Briffa, 2008 in M K Hughes, H F Diaz,
and T W Swetnam, editors. Dendroclimatology: Progress and Prospects.
National Research Council, 2006. Surface Temperature
Reconstructions for the Last 2,000 Years. Available at: http://books.nap.edu/openbook.php?isbn=0309102251.
Wahl, E R & Ammann, C M, 2007. Climatic Change,
Wegman, E J, Scott, D W & Said, Y H, 2006. Ad
Hoc Committee Report on the " Hockey Stick" Global Climate
28 ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/briffa2001jgr3.txt Back
Myth vs. Fact Regarding the "Hockey Stick". Back
March 31, 2006: Back
http://www.climate-gate.org/cru/documents/yamal/ and http://climateaudit.org/2010/01/04/what-happened-to-polar-urals/;
Apr 28, 2006 http://www.eastangliaemails.com/emails.php?eid=684 Back
http://climateaudit.org/2009/12/16/climategatekeeping/; 1054748574 Back
Jones successfully kept McKitrick and Michaels (2004) out of the
AR4 First and Second Drafts. After Review Comments, Jones reluctantly
included a reference together with a dismissive editorial comment
that was not based on any eligible peer reviewed literature, http://climateaudit.org/2009/12/17/climategatekeeping-2/; Back