A guest post by Nic Lewis
When the Lewis & Crok report “A Sensitive Matter” about climate sensitivity in the IPCC Fifth Assessment Working Group 1 report (AR5) was published by the GWPF in March, various people criticised it for not being peer-reviewed. But peer review is for research papers, not for lengthy, wide-ranging review reports. The Lewis & Crok report placed considerable weight on energy budget sensitivity estimates based on the carefully considered AR5 forcing and heat uptake data, but those had been published too recently for any peer reviewed sensitivity estimates based on them to exist.
I am very pleased to say that the position has now changed. Lewis N and Curry J A: The implications for climate sensitivity of AR5 forcing and heat uptake estimates, Climate Dynamics (2014), has just been published, here. A non-paywalled version of the paper is available here, along with data and code. The paper’s results show the best (median) estimates and ‘likely’ (17–83% probability) ranges for equilibrium/effective climate sensitivity (ECS) and transient climate response (TCR) given in the Lewis & Crok report to have been slightly on the high side. Continue reading →
Over the past year or so, Mann’s “ClimateBall” defenders have taken an increasing interest in trying to vindicate Mannian principal components, the flaws of which Mann himself has never admitted. Indeed, in Mann’s self-serving Hockey Stick Wars, Mann once again claimed that the defective method was simply an “alternative centering convention”. So far, I’ve taken little interest in such efforts because, as far as I’m concerned, the defectiveness of Mannian principal components is established beyond any reasonable cavil. My attitude towards such efforts is probably not unlike Andrew Lacis’ attitude towards skydragons and their supposed slayers.
But the rhetoric of such efforts has increased in both volume and intensity. In recent comments at at Judy Curry’s (here), Kevin O’Neill accused the Wegman Report of “real fraud”, citing, as one of his major counts, its supposedly “deceptive display of only upward-pointing ‘hockey sticks’ – though half of them would have had to be downward pointing” . O’Neill challenged Curry for her supposed failure to recognize “real fraud”. O’Neill’s explanation for the supposed “fraud” was that it was “pretty obvious that a downward sloping hockey stick wouldn’t look like MBH. The Wegman Report was a political hatchett job.”
However, the 2006 NAS Panel also showed only upside-up simulated PC1s in their figure 9-2 illustrating the bias in Mannian principal components, explaining that the sign of a principal component series is arbitrary (a point previously made in MM05) and therefore selecting the arbitrary sign to align the PC1s to be upward-pointing. In addition, the coauthors of Juckes et al 2007 (including Briffa, Osborn, Myles Allen) similarly observed that the sign of PC series is arbitrary and re-oriented them to match the 20th century trend. So, if the technique is “real fraud”, as O’Neill alleges, the supposed “fraud” reaches far beyond the walls of the Wegman report, including both the NAS panel and the coauthors of Juckes et al 2007, a conspiracy of Lewandowskian proportions.
Further, Mann himself flipped over the downward-pointing MBH99 PC1 not just in the regression, but for the calculation of the Mannkovitch bodge illustrated in MBH99 Figure 2. Jean S has ably exposed the Mannkovitch bodge, but even Jean S did not take exception to Mann re-orienting the MBH99 PC1 to be upward pointing. But if O’Neill is correct in characterizing such re-orientation as “deceptive” and as “fraud” (on which I firmly disagree), he would, ironically, be providing an additional reason for Steyn to have used the term “fraudulent” to describe the MBH99 hockey stick.
But, in fact, far from being “deceptive”, the technique used by the NAS Panel (and Wegman) is not only legitimate, but more appropriate than displays that fail to allow for the fact that the sign of a PC series is arbitrary.
Continue reading →
Things start rolling 9 AM (UK time), when Tim Osborn sends the new Briffa and recalibrated Jones (1998) time series to Phil Jones along with the suggestion to hide the decline.
It is ready calibrated in deg C wrt. 1961-90, against the average Apr-Sep land temperature north of 20N. It goes from 1402 to 1994 – but you really ought to replace the values from 1961 onwards with observed temperatures due to the decline.
Twenty minutes later Jones writes to the MBH crew (cc Briffa and Osborn) explaining WMO plans and exactly what the graph will look like.
Jones explained that the graph was intended for the cover of the WMO annual statement, which had a print run of 10,000. Jones said that he had voted against using the millennial series in the promotion because he knew that he had “oversold the advances in paleoclimate”:
The pertinent item from Geneva concerns the WMO statement on the Climate of 1999. WMO has been issuing these for the past 6 years. There are 10,000 printed each time. There were two possibilities for the front cover (1998′s showed the instrumental record from 1856) – the millennial long temperature series or the contrasting storm tracks for 1998 and 1999. I was the only one voting for the latter – partly personal as I knew I would have to organise the former. I was outvoted 12-1, maybe because in a brief presentation I oversold the advances made in paleoclimate studies over the last few years !
Jones explained the planned figure to MBH as follows:
WMO want to go with the millennial record on the cover and I said I would produce something and some text. The figure will be the 3 curves ( Mike’s, mine amd Keith/Tim’s). Tim is producing this curve (all wrt 61-90 and 50 year smoothed). Each will be extended to 1999 by instrumental data for the zones/seasons they represent.
Along is also attached the draft of the brief text to appear on p.4 of the report for the comments. Jones further brags about the importance of the WMO publication.
The full text of the report is then printed during Feb 2000 – last year’s was 12 pages long. It will be released on March 15 in Geneva to coincide with WM (World Met) day and the 50th anniversary celebrations of WMO as well. WMO are planning to print at least twice as many copies as usual and were talking about 25,000 ! Copies go to all WMO members and are distributed at countless meetings and sent to loads of address lists available.
After that Jones apparently begins to work with the times series. He’s ready 1:30 PM and sends the now infamous trick email. (Bradley appears to have commented already, but the email is not in the dossier.)
Once Tim’s got a diagram here we’ll send that either later today or first thing tomorrow.
I’ve just completed Mike’s Nature trick of adding in the real temps to each series for the last 20 years (ie from 1981 onwards) amd from 1961 for Keith’s to hide the decline. Mike’s series got the annual land and marine values while the other two got April-Sept for NH land N of 20N. The latter two are real for 1999, while the estimate for 1999 for NH combined is +0.44C wrt 61-90. The Global estimate for 1999 with data through Oct is +0.35C cf. 0.57 for 1998.
Thanks for the comments, Ray.
Note that Jones clearly explained what he means by “Mike’s Nature trick”. Mann has claimed that his “Nature trick” was nothing more than clearly showing observations and reconstructions on the same graphic with proper labeling. But the direct comparison of observations to reconstructions is as old as statistics – and Jones and Briffa had themselves made such comparisons in prior articles without regarding clear labeling as anything more than elementary hygiene. In this email (which is often shortened in quotation), Jones says that Mann’s “Nature trick” is “adding in the real temps to each series for the last 20 years (ie from 1981 onwards) amd from 1961 for Keith’s”, as originally explained in November 2009 here.
Two hours later Michael Mann, who according to his legal documents “had absolutely nothing to do” with the graph (that is still worth a mention in his CV ), responds. He completely agrees with the text adding that it will “help to bolster the claims to be made in IPCC [AR3]“:
The text looks good, and I agree w/ everything that is said. I think its a strong but defensible statement, and will help to bolster the claims to be made in IPCC. The ’99 numbers are very interesting, and should help thwart the dubious claims sometimes made that El Nino is the sole culprit in the anomalous recent warmth.
There is no objection to the graph, which, according to Mann’s book of Fairy Tales, is undisputably misleading (crediting the whole figure to Jones).
and Jones’s 1999 World Meteorological Organization (WMO) report cover graph depicting past temperature trends was criticized as potentially “misleading” for merging proxy and instrumental data into a single curve — a conclusion nobody really disputed.
Mann further tries to help by sending “for comparison” the draft version of the IPCC AR3 Figure 2-21, and explains a nice “trick” how to handle the baseline in the face of the decline.
Just for comparison to what Tim is producing, I’m attaching the plot you may remember that we (actually, the UK Met Office staff) prepared for the final version of the IPCC chapter 2 draft (in pdf format). To refresh your memory, we used the ’61-90 base period for the absolute anomaly scale, but we aligned the series based on an earlier (’31-60) interval of the instrumental record, which pre-dates (largely) the recent decline in the Briffa et al series. I think this leads to a similar picture, but if you think there are any significant discrepancies w/ what Tim is preparing, we should discuss.
Keith and Tim’s diagram is the new one that didn’t make it to the present IPCC draft. For the other two, yours has 0.12 added to it to correct your base period of 1902-80 (can’t remember your exact dates) to 1961-90. For mine we’ve used a mean and SD calculated by Tim based on April-September average temps from the NH Land series north of 20N.
There is no protest from the MBH crew after after seeing the figure, and only Malcolm Hughes comments an hour later.
Dear Phil – the text looks fine to me. I have no strong preference regarding the diagrams, except that hte one Mike circulated hs the advantage of sowing an estimate of uncertainties.
So far only Keith Briffa appears to have not made comments about the publication. However, we see his acceptance from the letter written next morning to an Elsevier editor inquiring if the new version for Briffa’s QSR (2000) Figure 5 had been substituted.
with regard to the earlier message ( copied below) could you confirm the the new Figure was substituted as I now wish to cite this in a forthcoming WMO publication that will be widely distributed.
QSR (2000) is the reference for Briffa’s series given in the WMO publication, and later in the IPCC AR3. The email is important on its own as it explains the troubles I (and George Kukla, see below) had 15 years later.
Apart from throwing Jones under the bus Mann’s defence line of this “overly simplified and artistic depiction” (per Mann’s Reply Memorandum) has been that the “simplified” figure was produced with a “largely nontechnical audience” in mind. The modern Arabian Nights tells us:
That, in short, was the “trick” that Jones had chosen to use to bring the proxy temperature series in his comparison up to the present, even though the proxy data themselves ended several decades earlier. There was one thing Jones did in his WMO graph, however, that went beyond what we had done in our Nature article: He had seamlessly merged proxy and instrumental data into a single curve, without explaining which was which. That was potentially misleading, though not intentionally so; he was only seeking to simplify the picture for the largely nontechnical audience of the WMO report
However, as can seen from the above, there was no consideration of the special audience when the graph was produced. Instead, Mann argued that it will “help to bolster the claims” to be made to the IPCC audience.
Further, it appears from the CG letters that the “overly simplified and artistic depiction” was further distributed among their colleagues for the scientific purposes. In February 2000, Bradley requests the figure for the possible use in the PAGES systhesis report.
can you send me another copy of the wmo figure that you prepared — at least, if it changed after 11/16/99. In re-visiting your notes on the one you sent then, it seems you were still fiddling with 40 or 50 year filters etc, so maybe the one i have isn’t final. We may end up using this in the PAGES synthesis chapter –I think it is different than the one Keith used in Science (May 7, 1999 –v284, p.927)
In April 2000 Jones sends the figure along with the spliced times series to Curtis Covey
The attached file has the data you want. There are 5 columns (mine, Mike Mann’s, Keith’s, Annual NH and JJA NH). The last two are instrumental and only start in the 1850s. Keith’s starts about 1400. All are wrt 1961-90. You will see that for the 3 multiproxy series this file has been extended to 1999 by adding in instrumental data for the season and region each was supposed to represent. The other attachment is a figure of the first 3 which has appeared on the front cover of the WMO statement for 1999.
and later in October 2000 to Jim Hurrell.
Tim can send you one with all the series in. wmocover.ps is what appeared on the front cover of the 1999 annual statement. On this the series have been extended with equivalent instrumental data to 1999.
In fact, it seems that they were so proud of the figure that they placed the graph on the back of the official CRU t-shirt, which Mann was more than happy to request.
p.s. I wear a medium ;)
The WMO figure makes one more appearance in the CG dossier. In a remarkable letter, worth reproducing in full, late George Kukla writes in January 2001 to Keith Briffa, in which Kukla asked Briffa about the inconsistency between the WMO presentation of the data and the decline shown in Briffa’s technical papers, describing the WMO presentation as “not very responsible”:
You are the only guy who may know what was and is going on in the northern forests. With respect to that I do not think that the WMO statement # 913 on the status of the global climate in 1999 is a sufficiently reliable last word. For one thing: the curve attributed to you doesn’t seem to jive with any of the figures of your 2000 QSR paper. Where from did they get the 0.6 degree departure at 1600 AD?
Another problem: the ring density and width in the last several decades are both decreasing which at any other
time would be interpretted as a sign of cooling. So why is it shown in the WMO report as an unprecedented warming? As you properly discuss in your papers we just do not know how exactly do the tree rings relate to weather. In my understanding we are left with the following options:
1) The calibrations of the rings to temperature prior to 1950 are biased, possibly due to the poor coverage of temperature stations.
2) Something other than the temperature influenced the trees in the last several decades and we do not know what.
In either case it is not very responsible to relate the curves to global climate as WMO has done. You are saying it, albeit somehow indirectly but pretty clearly, in all your papers. Unfortunately it appears that these are tooo long for WMO to read.
Ciao and greetings to everyone down there!
I think it’s fair to say that George Kukla was first to spot the Hide-the-Decline.
[Edit: By Barry’s request, “before” and “after” pictures:
In a recent post, I reported on the diagram in Jones 1998 (Science), which pushed hide-the-decline a year earlier than my previous inventory. (The Briffa bodge, an earlier technique, dates back to 1992 and Jones 1998 is a sort-of transition from the Briffa bodge to truncation as hide-the-decline technology.)
I’ve had a few requests for a fresh inventory of hide-the-decline incidents, updating the discussion of Oxburgh panelist Kerry Emanuel’s false claim to the US Congress that hide-the-decline had been limited to a “single lapse of judgement” in a “non peer-reviewed publication” (the WMO diagram). Continue reading →
In a twitter exchange among Jean S, Ronan Connolley and Tim Osborn, Ronan drew attention to an early spaghetti graph in a comment on MBH98 published by Phil Jones in Science on the day after (Apr 24, 1998) publication of Mann et al 1998. The Briffa reconstruction is in purple below. Like IPCC 2001, it hides the decline in the Briffa reconstruction (here a 1998 version) by deleting late 20th century values – here after 1950.
Jones stated that all three reconstructions “clearly show” that the 20th century is the warmest in the 600-year period, with the most “dramatic feature” being the 20th century rise:
Despite the different methods of reconstruction and the different series used, or alternatively, because a few good ones are common to all three series, there is some similarity between the series. All clearly show the 20th century warmer than all others since 1400. The dramatic feature of all three records is the rise during the 20th century.
Mann et al published a Reply to Jones’ comment in June 1998 (with Jones as coauthor of the Reply). They agreed that Jones’ spaghetti diagram “demonstrate[d] the the robustness of the conclusion that the 20th-century warming is unusual in the context of the past several centuries”L
The comparison shown by Jones between Mann et al.’s Northern Hemisphere temperature reconstruction (1) and two other recent estimates is useful in several ways. For example, it demonstrates the robustness of the conclusion that the 20th-century warming is unusual in the context of the past several centuries, on the basis of largely independent estimates.
However, these claims are based on hide-the-decline: Jones deleted post-1940 values of the Briffa reconstruction, slightly enhancing the effect of the deletion by smoothing with post-deletion values only. Jones noted this truncation in the caption to the figure, where he stated that “tree-ring density data show a decline since the 1940s unrelated to temperature [see (9 - Briffa et al, in press; 10 - Briffa et al 1998 (Phil Trans London)] for more details], and the curve from (9) ends at 1940″, a precaution not taken by Mann in IPCC AR3. In the next graphic, I’ve done a blow-up of the 1900-2000 portion of the graphic to demonstrate this. I’ve also shown the deleted values of the Briffa reconstruction (using the nhlmt version from Briffa et al 1998). This hide-the-decline incident is a year earlier than hide-the-decline in Briffa and Osborn 1999 and Jones et al 1999.
Figure 2. Blow-up of Jones 1998 comment on MBH98. Briffa version is nhlmt from Briffa et al 1998.
In the next graphic, I’ve plotted the complete series – no hide-the-decline. When the decline is shown, one feels that even a reviewer for Science or Nature would cavil at the assertion that the “dramatic feature of all three records is the rise during the 20th century” or that the conclusion that “20th-century warming is unusual in the context of the past several centuries” is “robust”:
Figure 3. Jones 1998 diagram, showing decline in Briffa et al reconstruction (nhd2 version rescaled on same ratio as nhlmt to nhd1 and re-centering to match visually.
Jones did make some sensible comments in his Comment that have not previously drawn attention. Jones observed that one should be able to easily extract relative importance of the various proxies, speculating that “much of their success, in a statistical sense” must come from tree rings:
The mathematical technique used by Mann et al. (3) to produce the reconstructions could easily be adapted to show which proxy series are the most important. Although Mann et al. (3) do not explicitly rank the various proxies, much of their success, in a statistical sense, must come from the large number of tree-ring width series used.
Jones’s observation was correct, but no one seems to have attempted extracting the contribution of different proxies types until I did so in 2004-2005. My analysis showed that the contribution of all proxies except bristlecones was little different than white-to-low-order-red noise and that the HS came from a very small subset of all proxies. The climate community has chosen to ignore this point.
Jones also made the sensible observation that each new class of proxy had to prove itself – a precaution immediately abandoned in favor of Mannian armwaving.
Each paleoclimatic discipline has to come to terms with its own limitations (6, 7) and must unreservedly admit to problems, warts and all. A particular issue for all ice core and coral series and some new tree-ring work is what exactly an isotope series (be it O, H, or C) tells us about past temperature. Sensitivity to temperature cannot be assumed; it must be proved with instrumental data on both interannual, and, where possible, on longer (more than 20 years) time scales (7).
I must say that I was a little intrigued to find an example of hide-the-decline a full year before Briffa and Osborn 1999 or Jones et al 1999, previously the earliest hide-the-decline example. In previous analyses of hide-the-decline, I’ve repeatedly emphasized that the technique of deleting data to hide inconvenient results originated with CRU (I’ve previously termed it “Keith’s Science Trick”). Mann knew of CRU’s deletion of the decline, but, as Lead Author of IPCC AR3, Mann willingly and enthusiastically participated in the hide-the-decline scheme, because he didn’t want to “give fodder to the skeptics” or “dilute the message”. But the technique originated with CRU and the “exoneration” of Jones, Briffa and Osborn on hide-the-decline by Muir Russell and Oxburgh was totally undeserved. (Nor does assignment of blame to CRU excuse Mann’s participation in hide-the-decline as Lead Author of AR3, where Mann and CRU both were culpable.)
Postscript: the twitter exchange also discusses the provenance of the Briffa reconstruction version in IPCC AR3 Figure 2-21. IPCC cited Briffa 2000 (QSR), while the actual version used in AR3 comes from Briffa et al 2001. Tim Osborn stated that the IPCC version matched the green LFD curve in Briffa (2000) Figure 5. This seems to be only partly true: the LFD curve has the same shape as the AR3 curve, but appears to be scaled differently.
Some comments have been accumulating on an unrelated topic. Please comment on this thread. I’ll try to write something over the next couple of days. But in a quick first look, Mann has re-iterated his untrue claims that various listed inquiries investigated and exonerated Mann personally. The untruthfulness of these claims has been discussed in a number of CA posts. I read a comment that Mann had coopered up some false quotations, but haven’t checked these claims.
Also, Mann’s brief does not address the arguments by ACLU and others against Mann’s assertion that the defendants were obligated to acquiesce in the findings of government inquiries, a proposition that ACLU and numerous major news media say is (though not using this exact word) unprecedented.
PCA was also performed on certain proxy sub-networks (spatially dense regional networks of tree-ring data available separately in different continents) as means of dimensional reduction of the predictor network. In this case, the procedure was performed separately for each independent step of the stepwise calibration/reconstruction procedure described in “3″ below. A decreasing number of PCs of these sub-networks are retained increasingly further back in time, as dictated by application of objective selection criteria (consideration of results of both Preisendorffers Rule N and Scree test).
We employed a standard, objective criterion for determining how many PCs should be kept for each region.
Michael E. Mann in his book.
Let’s continue with another housekeeping post.
When Steve and Ross uncovered Mann’s flawed PCA, Mann’s defence was that MM had failed to use Preisendorfer’s Rule N in the selection of the PCs in the NOAMER AD1400 step (for the background of this story, see here or read it from Montford’s excellent book). Steve observed immediately that the use of “Rule N” was not mentioned in MBH98 in connection to the tree ring PCA. He then emulated the claimed rule convincingly showing that it was pretty impossible that the rule was actually used. Further, up to now Mann has failed to reproduce any code or documentary evidence for the supposed use of the rule. It is hard to imagine, even in the context of the Hockey Stick, any other argument with so little support but which is still alive and well with the usual suspects. In fact, this fairy tale now seems to be the official story line in Wikipedia (citing Mann’s book, of course).
When I got my hands in the MBH9X file archive contained in the Climategate files, among the first things I checked was that if it contained the code for the selection rule, or even a file indicating the use of such code. Nope. Later I observed a curious thing in the files. MBH9X is a stepwise procedure, and in every step (if there were enough proxies), one supposedly (as the Corrigendum statement indicates) calculated the tree ring PCs. However, there were quite a few calculation steps missing from the archive. For instance, Stahle & Cleveland Oklahoma/Texas (STAHLE OK) precipitation chronologies had a single calculation step (AD1700) although they were also used in the later steps (AD1730, AD1750, AD1760, AD1800, and AD1820). I then checked the actual MBH98 data, and vola, I noticed that instead of calculating the PCs for the STAHLE OK network at, say, AD1820 step Mann had simply recycled the 1820-1980 part of the AD1700 step PCs (1700-1980)! The correspondence between the archive and the PCs actually used was almost one-to-one: every “missing” step in the archive matched the reuse of the PCs from the previous step in the MBH98 data. In other words, contrary what is claimed in the Corrigendum PCs were not calculated for every step.
So what has the above to do with the PC selection rule? Well, Steve had observed that there are three (*) cases (SOAMER AD1750, STAHLE SW AD1750, and NOAMER AD 1500), where MBH98 retains more PCs than in the previous step although the network does not change (i.e., the same proxies are inputs to the PCA). But it was not only that the network was (supposed to be) the same … the PCs were exactly the same as in the previous step! Of course then, it is impossible for any “rule” to retain different number of PCs. The most striking example comes from the NOAMER AD1500 step, which is using PCs from the AD1450 step. Mann is keeping 2 PCs in the AD1450 step, but in AD1500 step 6 PCs are retained from the same PC set!
As Steve has said several times, MBH9X is the gift that keeps on giving! When now preparing for this post, I discovered yet-another Mannian mystery. There is a single exception to the above mentioned correspondence between the archive and PCs actually used. Namely, PCs are calculated for the SOAMER AD1450 step, but no SOAMER PCs are used prior the AD1600 step. The corrigendum text cited in the beginning continues
PCs were no longer calculated back in time once a given network contained fewer than 7 available series (with the exception that PCs were calculated for the ‘Stahle Southwest U.S./Mexico network’ with 6 series available). Thus, although some series may be available further back in time, they may not have been used to calculate PCs. For example,there are 110 series available back to 1400, but only 95 are used because PCs were not calculated on 6 Australian and 6 South American ITRDB series and 3 ‘Vaganov’ series.
SOAMER contains 7 series in the AD1450 step. Why were none of those PCs used?
(*) Actually there is a fourth case (AUSTRAL AD1750), which is immaterial here as it has the corresponding calculation step in the archive.
The Mann Statement of Claim prominently displayed, as one of only two quotations from the “inquiries”, an extended quotation from the Myths vs Facts webpage, included as one of three Resources accompanying the EPA decision denying reconsideration of various petitions for reconsideration of the Endangerment Finding (though Mann’s Statement of Claim falsely cited the gazetted (Federal Register) denial decision itself as its source.) The Myths vs Facts document (as well as the Factsheet and Press Release, also linked as “Resources”) contained statements and assertions that were both untrue and which were undocumented in the actual language of the “formal” documents that they were supposedly supporting.
The identity of the authors (and reviewers, if any) is not disclosed in the supporting documents (RTP documents) for the denial decision – Jean S speculated a few days ago that Gavin Schmidt was involved in EPA’s supposed investigation and “exoneration” of Michael Mann; Schmidt has thus far refused to comment.
In today’s post, I’ll discuss who wrote (and possibly reviewed) the Myths vs Facts document. Continue reading →