In this installment, I’ll look at another technique in the climate auditor’s toolbox, namely selective quotation. Once again, our example case study will involve accusations by Steve McIntyre concerning the use of paleoclimatologist Keith Briffa’s tree-ring based reconstruction in a key figure from the IPCC Third Assessment Report.

Arguing from a cherrypicked selection of quotes from the “Climategate” emails, McIntyre has claimed that IPCC authors Chris Folland and Michael Mann pressured Briffa to submit a reconstruction that would not “dilute the message” by showing “inconsistency” with multi-proxy reconstructions from Mann and Briffa’s CRU colleague Phil Jones. Briffa “hastily re-calculated his reconstruction”, sending one with a supposedly larger post-1960 decline before. According to McIntyre, Mann resolved this new “conundrum” and simply “chopped off the inconvenient portion of the Briffa tree-ring data”.

But a review of the emails – including some that have never been quoted before – clearly contradicts McIntyre’s version of events:

Jones and Briffa were concerned that Mann had an outdated version of the Briffa reconstruction, and both urged the adoption of the newer “low frequency” one, more appropriate for comparison with other multi-century reconstructions.

Far from pressuring Briffa to change his reconstruction right away, Mann questioned whether an immediate change was required, or even possible, and counselled waiting for the next revision.

CRU colleague Tim Osborn advised Mann that he and Briffa “usually stopped” the “low frequency” reconstruction in 1960, and went one better in his later “resend” to Mann, by explicitly removing the post-1960 data.

I’ll also show how McIntyre has changed his narrative along the way , in an effort to prove that the true “context” of the famous “trick” to “hide the decline” is somehow an indictment of the IPCC. (Speaking of which, be sure to take the poll at the end about McIntyre’s next move). But first, once again, here is the cause of all the fuss, namely Figure 2-21 from Chapter 2 of the IPCC Third Assessment Report – Working Group I: The Scientific Basis (2001).

McIntyre has had a bee in his bonnet about this figure for a long time, as seen in a 2007 ClimateAusit post comparing Briffa and other IPCC authors to Martin Durkin of Great Global Warming Swindle fame.

The restoration of the excised Briffa data is shown in green. In my opinion, the difference between the appearance of the altered and unaltered data is “substantial”. The alteration of the data makes the proxy reconstructions appear far more uniform than they really were. Not only was there no “clear explanation” of the alteration of the data, but the citation was to a reference where the data had not been altered. Can you imagine the hysterics if Durkin had done this? … In IPCC, no questions are asked about the professionalism of the authors. Briffa was appointed lead author of the section in AR4.

Following the dissemination of the “Climategate” emails, though, McIntyre decided to shift his attack squarely onto lead authors Michael Mann and Chris Folland, while Briffa was portrayed as holding out, albeit briefly, against the “deletion” of post-1960 data in his reconstruction. McIntyre begins by announcing the true “context” of Phil Jones’s “hide the decline” email.

Much recent attention has been paid to the email about the “trick” and the effort to “hide the decline”. Climate scientists have complained that this email has been taken “out of context”. In this case, I’m not sure that it’s in their interests that this email be placed in context because the context leads right back to a meeting of IPCC authors in Tanzania, raising serious questions about the role of IPCC itself in “hiding the decline” in the Briffa reconstruction.

In fact, the email in question concerns Jones’s chart for a World Meterological Office report, but McIntyre was interested in tying this to the what he terms the IPCC’s “version” of the “trick”. McIntyre discussed the fallout from the first IPCC authors’ meeting in September 1999.

The emails show that the late 20th century decline in the Briffa reconstruction was perceived by IPCC as “diluting the message”, that “everyone in the room at IPCC” thought that the Briffa decline was a “problem” and a “potential distraction/detraction”, that this was then the “most important issue” in chapter 2 of the IPCC report and that there was “pressure” on Briffa and other authors to show a “nice tidy story” of “unprecedented warming in a thousand years or more”.

In support of this idea, McIntyre quoted the September 22, 1999 email from Chris Folland that kicked off the whole discussion:

But the current diagram with the tree ring only data somewhat contradicts the multiproxy curve and dilutes the message rather significantly… This is probably the most important issue to resolve in Chapter 2 at present. [Emphasis as added by McIntyre]

Soon after, I pointed out that that the main issue discussed was not the “decline”, but rather the lack of “low frequency” variation in the version of Briffa’s reconstruction used in the “zero-order” draft. I restored the missing passage from Folland’s email, thus demonstrating clearly the true situation. (In this and following excerpts, email passages omitted by McIntyre will be given in bold; the exchange between CRU scientists and Mann can be found here [May 24: Page numbers from the PDF of email exchanges have been added, along with archive email numbers. ]).

But the current diagram with the tree ring only data somewhat contradicts the multiproxy curve and dilutes the message rather significantly. We want the truth. Mike thinks it lies nearer his result (which seems in accord with what we know about worldwide mountain glaciers and, less clearly, suspect about solar variations). The tree ring results may still suffer from lack of multicentury time scale variance. This is probably the most important issue to resolve in Chapter 2 at present. [PDF p. 3, 938031546.txt]

After my post was brought to McIntyre’s attention, he shifted his story somewhat (resulting in a noticeable degree of incoherence).

Comments from readers have clarified that the issue at the Arusha meeting was that the Briffa reconstruction “diluted the message” more through its overall inconsistency as opposed to the decline, which was still relatively attenuated in the Arusha version. After the Arusha meeting, Briffa hastily re-calculated his reconstruction sending a new version to Mann on Oct 5, 1999 and it was this hastily re-done version that introduced the very severe decline that was hidden in the First Order Draft and Jones WMO Report.

In a subsequent comment, McIntyre referred to “a revised Briffa reconstruction that was bodged together and sent to Mann”, presumably in response to IPCC “pressure”. McIntyre also restored the missing quotes in the Folland email, but pretended this had nothing to do with the significant change he had been forced to make in the narrative.

McIntyre made much of Briffa’s response to Folland, which expresses some reservations about the draft text as written:

I know there is pressure to present a nice tidy story as regards ‘apparent unprecedented warming in a thousand years or more in the proxy data’ but in reality the situation is not quite so simple… [There are] some unexpected changes in response that do not match the recent warming. I do not think it wise that this issue be ignored in the chapter.

However, Briffa also referred to his latest work, another key passage omitted by McIntyre.

The multi proxy series (Mann et al . Jones et al) supposedly represent annual and summer seasons respectively, and both contain large proportions of tree-ring input. The latest tree-ring density curve ( i.e. our data that have been processed to retain low frequency information) shows more similarity to the other two series [i.e. Mann et al, 1999 and Jones et al, 1999 – 18/05/10]– as do a number of other lower resolution data (Bradley et al, Peck et al ., and new Crowley series – see our recent Science piece) whether this represents ‘TRUTH’ however is a difficult problem. [ PDF p. 4, 938031546.txt]

This is a broad hint that Briffa believed that some of Mann’s expressed reservations would be resolved by his updated “low frequency” reconstruction.

Mann replied that he was happy to include Briffa’s reconstruction. But he cautioned that any discrepancies needed to be explained (in an email only partially quoted by McIntyre – the bold section was omitted):

… [T]he major discrepancies between Phil’s and our series can be explained in terms of spatial sampling/latitudinal emphasis … [T]hat explanation certainly can’t rectify why Keith’s series, which has similar seasonality *and* latitudinal emphasis to Phil’s series, differs in large part in exactly the opposite direction that Phil’s does from ours. This is the problem we all picked up on (everyone in the room at IPCC was in agreement that this was a problem and a potential distraction/detraction from the reasonably concensus [sic]viewpoint we’d like to show w/ the Jones et al and Mann et al series. [ PDF p. 5, 938018124.txt]

Notice that this flatly contradicts McIntyre’s statement above that “everyone in the room at IPCC’ thought that the Briffa decline was a ” ‘problem’ and a ‘potential distraction/detraction’ “, a canard McIntyre half-heartedly corrected, but has repeated since, as I’ll show later.

At any rate, Briffa responded directly to this passage:

I am not sure this is true if the relevant series of ours is used. We need to reexamine the curves and perhaps look at the different regional and seasonal data in the instrumental record and over common regions in the different reconstructed series. We would be happy to work with you on this. Also remember that our (density )series does not claim hemispheric or annual coverage. [ PDF p. 11, 938125745.txt]

So yet again, Briffa suggested that his latest series would go some way to reconciling differences, as well as suggesting drilling down into the data for additional explanations.

Emails the next day make it even clearer that CRU scientists wanted to ensure that the new “low frequency” reconstruction be used, and that this was key to resolving inconsistencies. Here’s Phil Jones responding to Mann a day later, in an email that has never been quoted as far as I know.

One important aspect Keith will address is whether you’re using the latest Briffa et al curve. We know you’re not but the one with the greater low frequency and therefore much better chance of looking much better with the other two series, isn’t yet published. [PDF p. 8, 938121656.txt]

This can only be interpreted as a “heads up” that Mann should use a more up-to-date “low frequency” curve, one to be finalized soon and presumably published well before the IPCC deadline.

Mann responded:

1) I am definitely using the version of the Briffa et al series you sent in which Keith had restandardized to retain *more* low-frequency variability relative to the one shown by Briffa et al (1998). So already, the reconstruction I’m using is one-step removed from the published series (as far as I know!) and that makes our use of even this series a bit tenuous in my mind, but I’m happy to do it and let the reviewers tell us if they see any problem. If I understand you correctly, there is yet a new version of this series that is two steps removed from Briffa et al (1998)? Frankly, at this stage I think we have to go w/ what we have (please see Ian Macadam’s plot when it is available–I think the story it tells isn’t all that bad, actually) for the time being. Things as you say will change following review anyways. [ PDF p. 10, 938108842.txt]

Far from applying any pressure for a new version, Mann expresses doubt that such a version could be added in time to the imminent revision anyway and worries that it may be too far removed from the original reference.

But, like Jones before him, Briffa’s main concern appears to be that the most appropriate (as yet unpublished) “low frequency” curve be incorporated.

Also , I am not sure which version of the curve you are now refering to. The original draft did show our higher frequency curve i.e. the version with background changes effectively filtered out (intended to emphasise the extreme interannual density excursions and their coincidence with volcanic eruptions) . The relevant one here is a smoothed version in which low-frequency changes are preserved. I can supply this and it will be in press by the time of the next reworking of the text. [ PDF p. 5, 938018124.txt]

Thus, McIntyre’s contention that the “low frequency” reconstruction sent by Tim Osborne two weeks later was “hastily recalculated” under pressure from Folland and Mann can not be supported. Not only that, but Briffa explicitly stated (once again) that his latest work would overcome Mann’s reservations about inconsistency between the various reconstructions.

Be that as it may, McIntyre’s current narrative, as given in his March 2010 presentation at the University of Toronto’s Trinity College [PDF 2Mb], returned once again to emphasizing the “decline” as “diluting the message”. He also accused Mann of unilaterally removing the post-1960 data.

The Briffa reconstruction – with its late 20th century decline – was viewed by IPCC leadership as ‘diluting the message’ and being a potential ‘distraction/ detraction from the reasonably consensus viewpoint’ that they wanted to show. Briffa expressed reservations about the failure of the proxies to behave as expected and weakly urged that the issues not be ignored. …IPCC section author Mann resolved the conundrum. He chopped off the inconvenient portion of the Briffa tree ring data – the portion where it goes down – and tucked the end point under other data, giving a rhetorical impression of consistency.

But this too is not supported by the actual emails. Consider Tim Osborn’s email of October 5, where he sends Mann the latest “low frequency” reconstruction.

Dear Mike and Ian Keith has asked me to send you a timeseries for the IPCC multi-proxy reconstruction figure, to replace the one you currently have. The data are attached to this e-mail. They go from 1402 to 1995, although we usually stop the series in 1960 because of the recent non-temperature signal that is superimposed on the tree-ring data that we use. … It is not two-steps removed from Briffa et al. (1998), since the new series is simply a *replacement* for the one that you have been using, rather than being one-step further. [ PDF p. 15, 939154709.txt]

So Osborn is clearly suggesting that the series be stopped in 1960. Indeed, in reconstruction “spaghetti graphs” published both before and after the IPCC report, Briffa consistently stopped his low frequency MXD series in 1960, as can be seen in this chart published in Briffa & Osborne, Seeing the Wood for Trees, (1999, Science):

And, again, in Briffa et al, Low-frequency Temperature Variations from a Northern Tree Ring Density Network (2001, Journal of Geophysical Research):

Mann replied that it would be difficult to get the new reconstruction into the very first draft, but that it could come in later:

… I think it may be a bit too late (past the Oct 1 deadline) to make further revisions in the draft 1.0. It would be a bit of an imposition on Tom at this point given what he’s been through in finalizing the draft. However, I see no reason that we can’t make that revision when the paper comes back from expert review in a couple months. We’ll have the further advantage that the supporting manuscript you describe should be available at that point (a requirement in the IPCC peer-review process). I think we’ll all be looking forward to updating the plot w/ the latest series you describe… [ PDF p. 28, 939141116.txt]

And there the matter stood until February 28, 2000, when Mann wrote to Briffa to obtain the latest version, presumably for a major draft revision.

I need your newest northern hemisphere density-based tree-ring reconstruction and appropriate reference for updating IPCC. Please send in ASCII format as soon as possible so we can incorporate. I hope all is well. [ PDF p. 28, 951763817.txt]

Osborn responded on Briffa’s behalf:

Keith asked me to get back to you on this. The reconstruction is the same as the one I sent on the 5th October 1999, but I’m sending it again in case that e-mail isn’t handy. The reconstruction has now been published, in the following paper: Briffa K.R. (2000) Annual climate variability in the Holocene: interpreting the message of ancient trees. Quaternary Science Reviews 19, 87-105.



Osborn did send the same data, but with one important exception.

I’ve already truncated the series at 1960 because of the problems with the recent period. [ PDF p. 29, 951763817.txt]



So, once again, the accusation that it was IPCC lead author Mann who decided to “truncate the series at 1960” is clearly contradicted. Stopping the series at 1960 was the intention of the researchers all along, in conformity with their standard practice when comparing multi-centennial reconstructions in “spaghetti graphs”.

Many scientists have complained, with considerable justification, that a selection of emails plucked from context according to some undisclosed criteria, will inevitably give a misleading impression.

But the present review also demonstrates that many of the emails present in the “climategate” archive have been conveniently ignored in favour of a meagre selection of cherrypicked quotes marshalled to present a scenario diametrically opposed to the truth. To say the least, one should take the climate auditors’ version of “Climategate” with a huge grain of salt.

And with that, I ask readers to vote on what they think will happen next by considering possible answers to the inevitable question:

How will Steve McIntyre react to new evidence contradicting his current “trick” narrative concerning IPCC TAR Fig. 2-21?

I’ll be cutting off the poll on May 20, which happens to be two days after the Fourth International Climate Conference sponsored by the Heartland Institute. For the first time, Steve McIntyre and Ross McKitrick will both be in attendance, along with other luminaries featured in this blog, such as Alan Carlin and Chris de Freitas.

[Update, May 21: The poll has now closed. Judging from his recent presentation at the Heartland Institute sponsored International Climate Conference, it appears that Steve McIntyre has not changed his narrative and interpretation of the “climategate” emails of September 1999. Neither is there any indication, as far as I know, that McIntyre has responded to the facts presented above. Based on currently available information, then, McIntyre appears to have chosen option (b) and has ignored the evidence, at least so far. ]