Section 2.2 Responses

2. The allegation that CRU has colluded in attempting to diminish the significance of data that might appear to conflict with the 20th century global warming hypothesis The CRU group, in consultation with Professor Michael Mann, is alleged to have systematically attempted to diminish the significance of the Medieval Warm Period, evidenced by an email from Mann 4th June 2003: “I think that trying to adopt a timeframe of 2K, rather than the usual 1K, addresses a good earlier point that Peck made w/ regard to the memo, that it would be nice to try to “contain” the putative “MWP”, even if we don’t yet have a hemispheric mean reconstruction available that far back [Phil and I have one in review–not sure it is kosher to show that yet though–I’ve put in an inquiry to Judy Jacobs at AGU about this].” The use of the words “contain” and “putative” are alleged to imply an improper intention to diminish the magnitude and significance of the MWP so as to emphasise the late 20th century warming.


  2. What involvement have you had in “containing” the MWP?

6 Responses to “Section 2.2 Responses”

  1. Jimchip Says:

    1051638938 Apr 29, 2003 Briffa to Cook:

    Can I just say that I am not in the MBH camp – if that be characterized by an unshakable “belief” one way or the other , regarding the absolute magnitude of the global MWP. I certainly believe the ” medieval” period was warmer than the 18th century – the equivalence of the warmth in the post 1900 period, and the post 1980s ,compared to the circa Medieval times is very much still an area for much better resolution.

    Cook had emailed Briffa:
    Bradley still regards the MWP as “mysterious” and “very incoherent” (his latest pronouncement to me) based on the available data. Of course he and other members of the MBH camp have a fundamental dislike for the very concept of the MWP, so I tend to view their evaluations as starting out from a somewhat biased perspective, i.e. the cup is not only “half-empty”; it is demonstrably “broken”. I come more from the “cup half-full” camp when it comes to the MWP, maybe yes, maybe no, but it is too early to say what it is. Being a natural skeptic, I guess you might lean more towards the MBH camp, which is fine as long as one is honest and open about evaluating the evidence (I have my doubts about the MBH camp). We can always politely(?) disagree given the same admittedly equivocal evidence.

  2. jimchip Says:


    From: Jonathan Overpeck
    To: Stefan Rahmstorf
    Subject: Re: urgent help re Augusto Mangini
    Date: Sat, 7 Apr 2007 09:35:51 -0600
    Cc: Valerie Masson-Delmotte , Eystein Jansen , Keith Briffa

    Hi Stefan – Valerie was the lead on the Holocene section, so I’ll cc
    her. I agree that your approach is the smart one – it’s easy to show
    proxy records (e.g., speleothems) from a few sites that suggest
    greater warmth than present at times in the past, but our assessment
    was that there wasn’t a period of GLOBAL warmth comparable to
    present. We used the term likely, however, since there still is a
    good deal of work to do on this topic – we need a better global
    network of sites…

    …>Dear Peck and IPCC coauthors,
    >- I know it’s Easter, but I’m having to deal with Augusto Mangini, a
    >German colleague who has just written an article calling the IPCC
    >paleo chapter “wrong”, claiming it has been warmer in the Holocene
    >than now, and stalagmites show much larger temperature variations
    >than tree rings but IPCC ignores them. What should I answer?
    >One of my points is that IPCC shows all published large-scale proxy
    >reconstructions but there simply is none using stalagmites – so
    >please tell me if this is true?!! My main point will be the local
    >vs hemispheric issue, saying that Mangini only provides local
    >examples, while the IPCC statement is about hemispheric or global

  3. Jimchip Says:

    1066073000.txt Osborn to Mann. This could apply to 1.6, a lot of Sec. 5. EOS draft discussion re: rebuttal to S&B. It shows the care in crafting the language for a Sec. 2.2 purpose. or not, meh.

    From: Tim Osborn
    To: “Michael E. Mann”
    Subject: Re: draft
    Date: Mon Oct 13 15:23:20 2003
    Cc: Caspar Ammann ,, Keith Briffa ,,,,, Scott Rutherford , Tom Wigley ,, Kevin Trenberth

    At 20:02 09/10/2003, Michael E. Mann wrote:

    Dear All,
    I like all of Kevin’s changes. Please work with his version as a template for any
    additional suggested changes. I’ll incorporate the additional comments received from
    Phil and Tom W and others afterwards…

    Dear Mike and co-authors,
    I’ve now had a chance to go through the drafts and comments etc. Working from Kevin’s
    version, here are some suggestions to consider:
    (1) Are you sure that what we saw is the final version of S03, after any EOS editing,
    etc.? Wouldn’t want any of the S03 quotes used here to get changed if they had to edit to
    reduce the length of their piece!
    (2) Suggested re-ordering of the end of point (1): ‘it holds in some cases for tree-ring
    density measurements at higher latitudes, but rarely for annual ring widths.’
    (3) Suggested re-wording near start of point (2): ‘”clearly shows temperatures in the MWP
    that are as high as those in the 20th century” is misleading because it is true for only
    the early 20th century. The hemispheric warmth of the late 20th century is anomalous in a
    long-term context.’ (with underlining of either ‘late’ or ‘is’ for emphasis). Of course,
    this suggestion needs to be checked carefully (e.g., is it only the ‘early’ 20th century
    that is exceeded by some earlier temperatures?). But it is an important change because it
    is not actually ‘false’ or ‘untrue’ if some part of the 20th century was exceeded earlier –
    they don’t specify which part, so their statement is (probably deliberately) vague rather
    than wrong. The above suggestion simply points this out.
    (4) Related to this comment, is the question of whether the actual reconstruction (not
    instrumental observations) in the late 20th century exceeds all reconstructed values
    (central estimates) prior to the 20th century. My copy of Mann and Jones (2003) has poor
    quality figures, so this is hard for me to tell. It appears that it might be true, but
    only right at the end – i.e. the 1980 value of the filtered series. If it is really only
    at the end, and a 40-year smoothing filter is used, then I would be concerned about this
    statement appearing in the response if it depends upon applying the filter right up to the
    end of the record. Doing so requires some assumption about values past the end of the
    series. This in itself is problematic, but especially so if the assumption were that the
    trend was extrapolated to produce values for input to the filter. Of course, if the
    straight 40-year mean from 1941-1980 of the reconstruction exceeds all other 40-year means
    of the reconstruction, then I’d be happy with the statement.
    (5) I don’t like point (3) on the boreholes. It relies on the “optimal” borehole series of
    Mann et al. (2003), a result that I have some concerns about and which is being used here
    to imply less uncertainty than really exists over this issue. In the EOS paper we included
    this and the “non-optimal” gridded borehole series, so we were leaving open some
    uncertainty. I’m not saying that I prefer/believe the Huang et al. series either, since I
    agree that extracting the temperature signal from the borehole data is very difficult. I
    just don’t like to imply it has been solved when it hasn’t.
    (6) Can we provide a supporting reference for the statement in point (4) about land use
    changes leading to an overall cooling?
    (7) I like the final paragraph as it is, possibly dropping the last “We feel it is time to
    move on” line.

  4. Jimchip Says:

    1066149334.txt Mann to Caspar Amman still draft, still EOS S&B. STill late 20th cent. Boreholes, proxies. Boulton did not read the emails before he wrote his questions.

    From: “Michael E. Mann”
    To: Caspar Ammann
    Subject: Re: Fwd: Re: draft
    Date: Tue, 14 Oct 2003 12:35:34 -0400
    Cc: Tim Osborn , Malcolm Hughes , Keith Briffa ,,,,, Scott Rutherford , Tom Wigley ,, Kevin Trenberth

    thanks Caspar,
    I agree–its important to emphasize this point, and I’m glad you recognized that we were
    underplaying it…
    At 10:25 AM 10/14/2003 -0600, Caspar Ammann wrote:

    looks good to me. It is one of these points where they can persuade journalists that
    they are ‘correct’ and it actually got into newspapers and finally to the senate floor
    this way. The more we are able to explain why the first half of the 20th century warmed
    up naturally, the more confidence we get on the detection of the anthropogenic signal
    Michael E. Mann wrote:

    Dear All,
    In response to Caspar’s suggestion, which I agree with, I propose rephrasing item “2”
    as follows:
    2) The statement by S03 that the Mann and Jones [2003] reconstruction “clearly shows
    temperatures in the MWP that are as high as those in the 20th century” is misleading if
    not false. M03 emphasize that it is the late, and not the early or mid 20th century
    warmth, that is outside the range of past variability. Mann and Jones emphasize
    conclusions for the Northern Hemisphere, noting that those for the Southern Hemisphere
    (and globe) are indeterminate due to a paucity of southern hemisphere data. Consistent
    with M03, they conclude that, late 20th century Northern Hemisphere mean temperatures
    are anomalous in a long-term (nearly two millennium) context.
    Any comments?

    Delivered-To: [1]
    Date: Tue, 14 Oct 2003 09:18:37 -0600
    From: Caspar Ammann [2]
    Organization: NCAR
    User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.4) Gecko/20030624
    Netscape/7.1 (ax)
    X-Accept-Language: en-us, en
    To: “Michael E. Mann” [3]
    Subject: Re: draft
    Hi Mike,
    it now looks good to me indeed including the new last paragraph following Tom’s wording.
    The only point I would highlight a little more is in point 2): Maybe it could be stated
    that the early part of the 20th century is within the natural range whereas the late
    20th century, the main point of the AGU position statement and also in M03, is clearly
    outside. Please also add a second ‘n’ in my name…
    Cheers, and thanks for your momentum on this,
    Michael E. Mann wrote:

    Dear All,
    I agree with each of Tom W’s suggestions. Adopting them, by the way, brings us down to
    738 words.
    So pending any revised language from Keith/Malcolm in response to Michael O’s comment on
    paragraph 2, I’m putting out a last call for comments, sign-ons, etc…
    At 08:00 AM 10/14/2003 -0600, Tom Wigley wrote:

    Some minor points ….
    para. 2 — should it be ‘an’ ensuing rather than ‘the’ ensuing?
    para. 2 — I still think ‘each’ (line 3) is unnecessary
    para. 4 — no comma after ‘(and globe)’
    re boreholes, does the point about comparing late 20th century with a ‘much longer
    period’ 1000 years ago help us? Given that the 1000 years ago data is highly lowpass
    filtered, if one *did* have a series with a temporal resolution that allowed a
    legitimate comparison, then the likelihood of a warmer interval 1000 years ago must be
    In any event, the time scale issue will not be meaningful to most readers. The key point
    is the data reliability/uncertainty. I would just say something like …
    “…. taken into account. For times more than 500 years ago, uncertainties in the
    borehole reconstructions preclude any useful quantitative comparison.”
    Finally, I would like the last para. retained, but I suggest shorter wording as …
    “…. as indicating that SB03 misinterpreted and misrepresented the paleoclimatological
    literature. The controversy ….”.
    My problem here is twofold. First, they really say nothing directly about ‘mainstream
    scientific opinion’ (except that they clearly disagree with it). At issue is not the
    mainstream opinion, but their interpretation of the literature and their illogical
    conclusions. Second, they may have misrepresented the results of their work, but we do
    not address this issue so it comes here as a non sequitur. In fact, just what such
    ‘misrepresentation’ consists of, and why it might be judged as ‘misrepresentation’ is a
    subtle issue. Hence my revision — which retains the word ‘misrepresentation’, but in a
    different context.
    Michael E. Mann wrote:

    Thanks Tim and Malcolm,
    The latest round of suggestions were extremely helpful. I’ve accepted them w/ a few
    minor tweaks (attached). We’re at 765 words–I think AGU will let us get away w/ that…
    So, comments from others?
    At 02:11 PM 10/14/2003 +0100, Tim Osborn wrote:

    SO3 argue that borehole data provide a conflicting view of past temperature histories.
    To the contrary, the borehole estimates for recent centuries shown in M03 may be
    consistent with other estimates, provided consideration is given to statistical
    uncertainties, spatial sampling and possible influences on the ground surface [e.g.,
    snow cover changes–Beltrami and Kellman, 2003]. It is not meaningful to compare the
    late 20th century with a much longer period 1000 years ago [Bradley et al., 2003],
    especially given the acknowledged limitations [Pollack et al., 1998] of borehole data.

    Caspar M. Ammann
    National Center for Atmospheric Research
    Climate and Global Dynamics Division – Paleoclimatolog

  5. Jimchip Says:

    1067194064.txt E&E paper. Applies to Sec. 5 (S&B). “Baddies” at E&E. Repeated in Sec. 5.3 (Mann cc’s self)

    From: “Michael E. Mann”
    Subject: CONFIDENTIAL Fwd:
    Date: Sun, 26 Oct 2003 13:47:44 -0500

    Dear All,
    This has been passed along to me by someone whose identity will remain in confidence.
    Who knows what trickery has been pulled or selective use of data made. Its clear that
    “Energy and Environment” is being run by the baddies–only a shill for industry would have
    republished the original Soon and Baliunas paper as submitted to “Climate Research” without
    even editing it. Now apparently they’re at it again…
    My suggested response is:
    1) to dismiss this as stunt, appearing in a so-called “journal” which is already known to
    have defied standard practices of peer-review. It is clear, for example, that nobody we
    know has been asked to “review” this so-called paper
    2) to point out the claim is nonsense since the same basic result has been obtained by
    numerous other researchers, using different data, elementary compositing techniques, etc.
    Who knows what sleight of hand the authors of this thing have pulled. Of course, the usual
    suspects are going to try to peddle this crap. 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..
    Thanks for your help,

    two people have a forthcoming ‘Energy & Environment’ paper that’s being unveiled tomoro
    (monday) that — in the words of one Cato / Marshall/ CEI type — “will claim that Mann
    arbitrarily ignored paleo data within his own record and substituted other data for
    missing values that dramatically affected his results.
    When his exact analysis is rerun with all the data and with no data
    substitutions, two very large warming spikes will appear that are greater than the 20th
    Personally, I’d offer that this was known by most people who understand Mann’s
    methodology: it can be quite sensitive to the input data in the early centuries.
    Anyway, there’s going to be a lot of noise on this one, and knowing Mann’s very thin
    skin I am afraid he will react strongly, unless he has learned (as I hope he has) from
    the past….”

    The to list to a confidential email:
    To: Ray Bradley , “Malcolm Hughes” , Mike MacCracken , Steve Schneider , tom crowley , Tom Wigley , Jonathan Overpeck ,, Michael Oppenheimer , Keith Briffa , Phil Jones , Tim Osborn ,, Ben Santer , Gabi Hegerl , Ellen Mosley-Thompson , “Lonnie G. Thompson” , Kevin Trenberth

  6. Jimchip Says:

    Tamino trying to cover up Mann PC1 see also 3.2 for a different quote

    Tamino’s main effort in this post is an attempt to claim that Mannian non-centered principal components methodology is a legitimate methodological choice. This would seem to be an uphill fight given the positions taken by the NAS Panel and the Wegman Panel – see also this account of a 2006 American Statistical Association session. However, Tamino makes a try, claiming that Mannian methodology is within an accepted literature, that it has desirable properties for climate reconstructions and that there were good reasons for its selection by MBH. I do not believe that he established any of these claims; I’ll do a post on this topic.

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