Section 1.4 Response

The terms of reference are as follows:

1.1 Examine the hacked e-mail exchanges, other relevant e-mail exchanges and any other information held at CRU to determine whether there is any evidence of the manipulation or suppression of data which is at odds with acceptable scientific practice and may therefore call into question any of the research outcomes.


1. The allegation of ignoring potential problems in deducing palaeotemperatures from tree ring data that might undermine the validity of the so-called “hockey-stick” curve. In the late 20th century, the correlation between the tree ring record and instrumental record of temperature change diverges from that for the earlier period. The cause of this divergence does not appear to be understood. If the method used to deduce temperatures from tree ring proxy metrics for the earlier tree ring record is applied to the late 20th century tree ring series, then declining temperatures would be deduced for the late 20th century. It is alleged that if the cause of divergence between the tree ring and instrumental temperature record is unknown, it may have existed in earlier periods.  Therefore if tree rings had similarly failed to reflect the warming of the early Middle Ages, they may significantly under- estimate the warming during the Medieval Warm Period, thus falsely enhancing the contrast between the recent warming and that earlier period.  (It is this contrast that has led to statements that the late 20th century warming is unprecedented during at least the last 1000 years.)


 4. What attempts have you made to resolve it?


One Response to “Section 1.4 Response”

  1. Jimchip Says:

    1104855751 04 Jan 2005 (Jones to Osborn): The whole email should be read.
    “I would immediately delete anything you receive from this fraud.
    You’ve probably seen now the paper by Wahl and Ammann which independently exposes
    McIntyre and McKitrick for what it is–pure crap.”

    in response to McIntyre to Jones:
    “I have noticed the following statements in Rutherford et al [2004], in which you are a co-author. As compared with some of your co-authors, I get the impression that, while you feel very strongly about your views, you are also concerned with getting to the bottom of matters and are less concerned with scoring meaningless debating points. In this spirit, I draw your attention to some incorrect statements in Rutherford et al.
    [2004] concerning our material. There is really a quite serious problem with the PC methods in MBH98 and the comments made in Rutherford et al [2004] are really quite misleading. For the reasons set out below, I request that these comments be removed from the manuscript.”

    11048993567 4 Jan 2005 (Overpeck to Briffa):
    “pp. 8-18: The biggest problem with what appears here is in the handling of the greater variability found in some reconstructions, and the whole discussion of the ‘hockey stick’. The tone is defensive, and worse, it both minimizes and avoids the problems. We should clearly say (e.g., page 12 middle paragraph) that there are substantial uncertainties that remain concerning the degree of variability – warming prior to 12K BP, and cooling during the LIA, due primarily to the use of paleo-indicators of uncertain applicability, and the lack of global (especially tropical) data. Attempting to avoid such statements will just cause more problems.
    In addition, some of the comments are probably wrong – the warm-season bias (p.12) should if anything produce less variability, since warm seasons (at least in GCMs) feature smaller climate changes than cold seasons. The discussion of uncertainties in tree ring reconstructions should be direct, not referred to other references – it’s important for this document. How the long-term growth is factored in/out should be mentioned as a prime problem.

    1121871795 Jul 20, 2005 (Briffa to Osborn):
    From: “Ricardo Villalba”
    To: “Jonathan Overpeck” ,
    “Edward R. Cook”
    Cc: “Keith R. Briffa” ,

    Subject: Re: the regional section and MWP Figure
    “Please, find attached the new version of the SH figure for the IPCC.
    I have now included the New Zealand record. All the records have been scaled to 4 °C amplitude. Variability in the Tas record is reduced compared to New Zealand and Patagonian records. The reference lines is the mean used for the calibration period in each record, 15 C for New Zealand, 14.95 C for Tasmania and 0 C for the Patagonian records (they show departures). Please, let me know if you want to introduce some changes in the figure. The opposite phase in the Patagonia-New Zealand records is so clear before 1850,
    which is consistent with our previous TPI. For instance, in the instrumental record the 1971 and 1976 are the coolest summer in northern Patagonian during the past 70 years, but the warmest in New Zealand reconstruction!! This out of phase relationship between regions in the Southern Hemisphere points out to the difficulty of using few records to get a hemispheric average.

    >Given the nature of the SH and what Ricardo put
    >together, I would keep the Australian and South
    >Aftrican borehole records separate.”

    1133366680 30 Nov 2005 (Mann to Osborn):
    “fair enough, I’ll go w/ flimsy. The real problem is the fairly
    inflammatory wording of this, and the really flawed interpretations
    w.r.t. implicatinos for natural vs. anthropogenic variaiblity. normally I’d ignore, but the fact that Andy Revkin received this suggests they are trying to publicize this review paper, which I find a
    bit odd…
    >>> Quaternary Science Reviews, Volume 24, Issues 20-21 , November 2005,
    >>> Pages 2164-2166
    >>> Climate: past ranges and future changes
    >>> Jan Esper a), Robert J.S. Wilson b), David C. Frank a), Anders
    >>> Moberg c), Heinz Wanner d) and Jürg Luterbacher d)
    >>> Abstract
    >>> Comparison of large-scale temperature reconstructions over the past
    >>> millennium reveals agreement on major climatic episodes, but
    >>> substantial divergence in reconstructed (absolute) temperature
    >>> amplitude. We here detail several research priorities to overcome
    >>> this ‘amplitude desideratum’, and discuss the relevance of this
    >>> effort for the prediction of future temperature changes and the
    >>> meaning of the Kyoto protocol…”

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