Yamal and Hide-the-Decline

 

In The Climate Files, Fred Pearce wrote:

When I phoned Jones on the day the emails were published online and asked him what he thought was behind it, he said” It’s about Yamal, I think”.

Pearce continued (p 53):

The word turns up in 100 separate emails, more than ‘hockey stick’ or any other totem of the climate wars. The emails began with it back in 1996 and they ended with it.

Despite Jones’ premonition and its importance both in the Climategate dossier and the controversies immediately preceding Climategate, Yamal and Polar Urals received negligible attention from the “inquiries”, neither site even being mentioned by Kerry Emanuel and his fellow Oxburgh panellists.

I recently submitted an FOI request for a regional chronology combining Yamal, Polar Urals and “other shorter” chronologies referred to in an April 2006 email – a chronology that Kerry Emanuel and the “inquiries” failed to examine. The University of East Anglia, which seems to have been emboldened by the Climategate experience, not only refused to provide the chronology, but refused even to provide a list of the sites that they used to construct the regional chronology.

This refusal prompted me to re-appraise Yamal and its role in the Climategate dossier.

Yamal at the Start and End of the Emails
Although the climate science community has represented Climategate as being about the CRU temperature record, the temperature record is only mentioned in a couple of emails.

The dossier is not about CRUTEM, it’s about the Hockey Stick. And within that debate, the dossier was seemingly constructed with particular attention to Yamal. Pearce’s observation about the Climategate dossier beginning with Yamal is literally true. The very first email (1. 0826209667.txt) is about Yamal – an opening scene wittily described by Michael Kelly in an overlooked account of the emails shortly after they became public:

Like an Aristophanes satire, like Hamlet, it opens with two slaves, spear-carriers, little people. Footsoldiers of history, two researchers in a corrupt and impoverished mid-90s Russia schlep through the tundra to take core samples from trees at the behest of the bigger fish in far-off East Anglia. Stepan and Rashit don’t even have their own e-mail address and like characters in some absurdist comedy must pass jointly under the name of Tatiana M. Dedkova. Conscientious and obliging, they strike a human note all through this drama. Their talk is of mundane material concerns, the smallness of funds, the expense of helicopters, the scramble for grants. They are the ones who get their hands dirty, and their vicissitudes periodically revived my interest during the slower stretches of the tale, those otherwise devoted to abstruse details of committee work and other longueurs. ‘We also collected many wood samples from living and dead larches of various ages. But we were bited by many thousands of mosquitos especially small ones.’ They are perhaps the only likeable characters on the establishment side, apart from the exasperated and appalled IT man Harry in the separate ‘Harry_read_me’ document, and I cheered up whenever they appeared.

The relatively unexplored data accompanying the emails is mostly tree ring data and contains interesting tree ring data not otherwise available, some of which I’ve used in today’s post (see below).

And, as Pearce observed, the closing scenes of the Climategate dossier showed CRU’s reaction to a series of posts at Climate Audit on Yamal in October 2009, which, together with the nearby Polar Ural site, had been a longstanding issue at Climate Audit.

The controversy in October 2009 was actually the second major CA dispute involving tree ring chronologies from NW Siberia. The earlier criticism was of CRU’s failure to publish an amendment to the prominent Polar Urals chronology (Briffa et al Nature 1995) to show the impact of measurement data that became available subsequent to the original publication (the availability of new data and its value in firming up the Polar Urals chronology timing is referred to in a 1999 email). As reported here, the new data showed a prominent MWP, contradicting Briffa et al 1995 on a cold 11th century.

CRU’s failure to report the update and the seemingly opportunistic adoption of the hockey-stick shaped Yamal chronology in its place had been the topic of many Climate Audit posts, some of which attracted CRU notice (as evidenced by the emails). I unsuccessfully raised the issue in AR4 review comments. CRU’s written evidence to Muir Russell defended their failure to publish or use an updated Polar Urals chronology on the simple fact that they had never updated or reanalysed their Polar Urals chronology subsequent to its publication:

We had never undertaken any reanalysis of the Polar Urals temperature reconstruction subsequent to its publication in 1995.

Given the shortage of 1000-year chronologies, one would have thought that additional data for the long Polar Urals chronology would have been eagerly awaited by its proponents, but seemingly not.

On the other hand, as Mosher has frequently observed, it is almost characteristic for Briffa to make totally contradictory statements within the same article and their evidence to Muir Russell is no exception. Having clearly said that they never reanalysed Polar Urals, CRU then alluded to reanalysis of the Polar Urals record. I’ll try to analyse this evidence on a future occasion; in the meantime, interested readers should consult the submission themselves.

The October 2009 Controversy

The Yamal issue in October 2009 (on the eve of Climategate) arose out of Briffa et al 2008 (Phil Trans B), the data for which had just become available in late September 2009 through the intercession of the editors of Phil Trans B – a journal not specializing in climate and thus not prepared to abet Team data obstruction.

Briffa et al 2008 purported to show “regional” chronologies for three northern Eurasian areas. One regional chronology combined data over a large area including both Finland and Tornetrask, Sweden. A second regional chronology (Avam-Taymir) substantially expanded the Taymir chronology of Briffa 2000 through the addition of sites from Sidorova 2007 (mentioned in the text) and the Schweingruber network (Briffa et al Nature 1998.) The effect of the additions was to somewhat mitigate the decline in the prior chronology. Both networks were very large in their modern portion – each had well over 100 cores. However, the network labeled as a “regional chronology” for Yamal did not expand from the Briffa 2000 network, even though this network had only a fraction of the sample in the other networks – only 10 cores in 1990 and 5 cores in 1995.

The precedent of the addition of Schweingruber sites at Taimyr raised the question why Schweingruber sites weren’t added to the Yamal network to make a truly regional chronology along the lines of the other two. Aside from nearby Polar Urals, there was even a Schweingruber site at the very location of a large proportion of the subfossil samples used in the Yamal network (Khadyta River, Yamal). I raised this issue at CA in a series of posts (see here). The matter was covered even in mainstream press. Ross stated the issue sharply in a National Post op ed in October 2009 as follows:

Combining data from different samples would not have been an unusual step. Briffa added data from another Schweingruber site to a different composite, from the Taimyr Peninsula. The additional data were gathered more than 400 km away from the primary site. And in that case the primary site had three or four times as many cores to begin with as the Yamal site. Why did he not fill out the Yamal data with the readily-available data from his own coauthor? Why did Briffa seek out additional data for the already well-represented Taimyr site and not for the inadequate Yamal site?

This time, CRU responded with online posts here on October 1, 2009 and here on October 27, 2009. The latter post came only three weeks before Climategate and hasn’t been fully analysed to date.

In the October 27 article, Briffa conceded that the Schweingruber Khadyta River dataset did meet CRU’s criteria for inclusion in a regional chronology (thus contradicting NASA blogger Gavin Schmidt who had sneered at the idea in an earlier real climate post here.) Briffa’s excuse was similar to the one later provided in connection with their failure to report on the updated Polar Urals data. They explained their failure to include the data in a regional chronology as due only to the fact that “we simply did not consider these data at the time”:

Our current practice when selecting data to incorporate in a regional chronology, is to include data exhibiting high levels of common high-frequency variability (i.e. on the basis of high inter-site correlations, where these are calculated using high-pass filtered data). Judged according to this criterion it is entirely appropriate to include the data from the KHAD site (used in McIntyre’s sensitivity test) when constructing a regional chronology for the area. However, we simply did not consider these data at the time, focussing only on the data used in the companion study by Hantemirov and Shiyatov and supplied to us by them.

In evidence to Muir Russell published after the inquiry, they expanded slightly on this “explanation”, re-iterating that they never “considered” the Schweingruber data, adding that the “purpose of the work” reported in Briffa et al 2008 was merely to “reprocess the existing dataset of Hantemirov and Shiyatov”:

McKitrick is implying that we considered and deliberately excluded data from our Yamal chronology. The data that he is referring to were never considered at the time because the purpose of the work reported in Briffa (2000) and Briffa et al. (2008) was to reprocess the existing dataset of Hantemirov and Shiyatov (2002).

This “purpose” is nowhere stated in the actual text of Briffa et al 2008. A reviewer or editor, aware that this was the actual “purpose” of the article, would surely have asked the authors to, for example, describe the differences between the new method and previous methods and to show the actual impact of the new method on the Yamal dataset, none of which is described in the article. Any reviewer, editor or reader of the actual text of Briffa et al 2008 cannot help but presume that its “purpose” was not to show the reprocessing of the Hantemirov and Shiyatov 2002 data, but to present regional chronologies expanding the network of Briffa 2000 though the combination of sites.

In CRU’s evidence to Muir Russell, Briffa, with his characteristic inconsistency, contradicted his earlier statement that they had not “considered” the possibility of additional data. Not only did he contradict this earlier statement, he stated that the original intention and objective of the Briffa et al 2008 article was to produce an “integrated Polar Urals/Yamal series” (along the lines that Climate Audit had wondered about), and that this objective was not pursued only because “it was felt that this work could not be completed in time”:

Some historical context for our 2008 paper might shed some light on this issue. Some time ago we began work on a multi-institution paper intended to describe the sensitivities in producing tree-ring-based climate reconstructions to the methods of chronology construction and subsequent climate calibration, illustrated using the examples of various tree-ring chronologies across northern Eurasia. When we later received a request to submit a paper to a planned themed issue of the Philosophical Transactions of the Royal Society about ‘The boreal forest and global change’, Briffa and colleagues decided to use some of the material to hand in preparing a draft. It was intended that this should describe 3 continuous 2000-year ring-width series, each originally planned to represent the integration of a large-regional data set of subfossil and living tree data. The focus was to be on representing large-regional growth signals and initial comparisons with equivalent regional temperature data. The western, ‘Fennoscandia’, series would incorporate near tree-line pine data from northern Sweden and Finland; the Avam-Taimyr series would integrate larch data from near the Taimyr peninsula tree-line region.

Between these we had intended to explore an integrated Polar Urals/Yamal larch series but it was felt that this work could not be completed in time and Briffa made the decision to reprocess the Yamal ring-width data to hand, using improved standardization techniques, and include this series in the submitted paper.

Hide the Decline

I’ve referred here to Schweingrubers sits. These are of course familiar to readers because the Schweingruber network was the data used in the Briffa MXD reconstruction of hide-the-decline notoriety. As shown below, Yamal is in the heart of hide-the-decline country in northern Siberia. The figure below shows the location of Yamal on the location map ( Figure 1) of Briffa et al 1998 (Nature), a figure that compared 1975-1985 tree ring values to 1935-1945 values (MXD left; ring width right). The graphic on the left also shows the location of Schweingruber sites – plentifully represented in Russia, to say the least. Briffa et al 1998 Figure 2 showed MXD and ring width chronologies from 1880-1992, with the third row in the panel showing a pronounced decline for West Siberia

Figure 1 Spatial patterns of relative tree-growth decline. a, The location (circles) of tree-ring chronologies and the division (black lines) into regional averages. b, The locations (black lines) of the grid-box temperatures used for comparison with the tree growth series. The coloured contours show where the ring density (a) and ring width (b) are enhanced (positive) or suppressed (negative) relative to summer temperature during the period 1975–85 compared to the period 1935–45.

In most scientific endeavours, one presumes that specialists would wonder why Yamal had a huge hockey stick, when it was located in a zone with dozens of sites showing a decline. However, no such reflection took place among paleoclimatologists. None seem to have wondered about the validity of the Yamal proxy. And even though Briffa’s chronology was never being formally published (it was shown only passim in Briffa 2000, which did not even report core counts), its use spread rapidly among paleoclimatologists – I sarcastically termed the Yamal chronology as “cocaine” for paleoclimatologists (bristlecones were, of course, heroin) and, from time to time, reflected on how to insert musical accompaniment from, respectively, Eric Clapton and the Velvet Underground whenever either proxy appeared.

Not only was the Yamal chronology widely adopted, the evidence of a decline in a network of nearly 400 sites (with hundreds of cores, not 10) came to be discounted. In Kerry Emanuel’s recent testimony, he stated that the evidence from the very large Schweingruber network was “provably false”, a position that has not been contradicted by any dendroclimatologist.

The Vaganov Network
As noted above, in their online response of October 2009, CRU conceded that it was entirely legitimate to include the Khadyta River and other sites highly correlated to Yamal in their regional chronology, explaining their inclusion practice as follows:

Our current practice when selecting data to incorporate in a regional chronology, is to include data exhibiting high levels of common high-frequency variability (i.e. on the basis of high inter-site correlations, where these are calculated using high-pass filtered data). Judged according to this criterion it is entirely appropriate to include the data from the KHAD site (used in McIntyre’s sensitivity test) when constructing a regional chronology for the area.

Although they said that they had not previously “considered” the use of additional data, they now said that the best approach to developing a chronology was “making use of all the data to hand”:

So what is the “best” indication of relative ring-width changes in this Yamal region? One approach is to judge this by making use of all the data to hand.

To that end, they stated that they had “taken the opportunity to acquire and incorporate additional data from the 3 original sites” [POR, YAD, JAH]. (The Climategate documents showed that they had actually had this data since 1996 or so). They produced another chronology including this data with the Khadyta River (KHAD) data that I had previously identified, arguing that this new chronology was similar to the original Briffa 2000 and Briffa 2008 chronologies and that therefore their previous failure to report a regional chronology didn’t matter, a viewpoint quickly accepted by the climate science community.

But there are some important loose ends.

The CRU (October 2009) position only permits a “limited hangout” (to borrow the Nixonian phrase.) Khadyta River is only one of dozens of Schweingruber sites, a number of which are close to Yamal. In addition, Eugene Vaganov, a prominent Russian dendrochronologist, had also made a large network (61 sites) in the early 1990s overlapping the Schweingruber network in Russia and many of his sites are also near Yamal. This data was never archived, but became available in the Climategate documents.

The figure below shows a detail from the Briffa et al 1998 location map on which the Schweingruber sites are shown in orange, the Vaganov sites in red, Yamal in limegreen. I’ve also added a box showing 10 degrees east-west of the Yamal sites and 65-70 degrees latitude that I’ve used to extract subsets for comparison. Within this box, there are 20 Vaganov sites and 15 Schweingruber sites, all of which (as shown below) appear to meet the relevant standards for inclusion in a regional chronology.

Figure 2. Excerpt from Briffa et al (Nature 1998) Figure 1 showing Western Siberian location.

The next figure shows compares core counts in the Vaganov and Briffa 2009 networks. The Vaganov network has 400-500 cores over most of the 20th century. In contrast, the living tree portion of the Yamal “network” in Briffa (2000) and Briffa et al 2008 had only 17 cores (10 in 1990; 5 – in 1995). The somewhat expanded Limited Hangout network of Briffa 2009 still contained only 11-12% of the number of cores of the Vaganov network and thus falls far short os using “all” the data. (It didn’t even use the Polar Urals data.)

Figure 3. Core counts for Vaganov and Briffa networks.

The effect of using “all the data to hand” is potentially quite dramatic. The graphic below compares the Briffa 2009 chronology (red) to the average of site RCS chronologies for the 20 Vaganov sites in the 10-degree box. As you can see, there is considerable correlation between the two chronologies, though the Briffa version is spikier than the much larger Vaganov network. The discrepancy becomes very pronounced from the 1970s on – the Vagnov network shows the characteristic “decline” in the late 20th century that also characterized the large Schweingruber network, while the Briffa Limited Hangout network surges to new records.

Figure 4. Comparison of Briffa 2009 chronology and regional chronology from Vaganov data.

The difference between the two results arises because the difference arising from the closing values of the POR and YAD sites in a small network. If they are added into the 20-site Vaganov network, their influence is diluted, but when there are only two other sites (JAH and KHAD), they still yield high closing values.

I’ve observed on other occasions that the Yamal hockeystick is typically very important in multiproxy reconstructions that don’t use bristlecones. In addition to Briffa 2000 and Briffa et al 2008, it is used in Briffa and Osborn 1999; Mann and Jones 2003; Bradley, Hughes and Diaz 2003; Jones and Mann 2004; Moberg et al 2005; D’Arrigo et al 2006; Osborn and Briffa 2006; Hegerl et al 2007; Mann et al 2008 (blended into the Tornetrask version) and Kaufman et al 2009.

Climategate
The Climategate emails contain much information about Yamal and Polar Urals, none of which is referred to by any of the various “inquiries”. I won’t survey all the emails in this note but will touch on some of the most important.

CRU awareness both of the existence of the updated Polar Urals measurement data (Schweingruber’s polurula dataset) and the close relationship between Polar Urals and Yamal is shown in email 1136918726.txt on Jan 10, 2006 from Wigley to Briffa. (This is also the email in which Wigley wonders whether a “reindeer crapped next to one of the trees”.)

Keith,

Thanx for this. Interesting. However, I do not think your response is very good. Further, there are grammatical and text errors, and (shocking!!) you have spelled McKitrick wrong. This is a sure way to piss them off.

They claim that three cores do not cross-date for TRW. They also say (without results) that the same applies to MXD (these results may be in their Supp. Mat. — I presume you checked this).

So, all you need say is …

(1) TRW was not the only data used for cross-dating.
(2) When MXD is used there are clear t-value peaks, contrary to their claim. You can show your Fig. 4 to prove this.
(3) The 3-core-composite cross-dates with other (well-dated) chronologies (Yamal and Polurula), confirming the MXD-based dating. You can show your Fig. 5 to prove this.

You could say all this in very few words — not many more than I have used above. As it is, your verbosity will leave any reader lost.

There are some problems still. I note that 1032 is not cold in Yamal. Seems odd. Is it cold in *all* of the three chronologies at issue? Or did a reindeer crap next to one of the trees?

Also, there seems to be a one-year offset in the 1020s in your Fig. 6.

I hope this is useful. I really think you have to do (and can do) a better job in combatting the two Ms. If this stuff gets into Nature, you still have a chance to improve it. Personally, I think it would be good for it to appear since, with an improved response, you can make MM look like ignorant idiots.

Tom

This email had been prompted by our submission of short comment criticizing crossdating in the Polar Urals data (Briffa et al 1995), an important element in the medieval-modern comparison of Jones et al 1998, (which I had moved on to after MBH98). In their response, they referred to the close relationship with Yamal (permitting the use of the Yamal chronology for crossdating Polar Urals), but notably did not mention the updated Polar Urals measurements, which we had not referred to in our submission.

Subsequent to the publication of Briffa et al. (1995), completely independent ring-width data have become available for the Yamal area adjacent to Polar Urals (Hantemirov & Shiyatov 2002). Comparisons between ring-width data for each of the early Polar Urals cores under discussion and the Yamal chronology (freely available to MM on my website) all confirm our original dating.

Their response referred to various figures, none of which were provided to us. Nor were the statements in their response correct. Comparisons to the additional Polar Urals measurement data and Yamal confirm our original observation of misdating of the 11th century cores used in Briffa et al 1995 and applied in the Jones et al 1998 reconstruction that is still in use.

Perhaps the most important email concerning Yamal was in April 2006 ( 684. 1146252894.txt ). It was one of only two emails that I referred to in the running text of my own submission to the Parliamentary and Muir Russell committees.

Osborn had emailed Philip Brohan of the UK Met Office (cc Briffa) describing CRU’s three regional chronologies (a single series for each) for the three regions later used in Briffa et al – SCAND, URALS and TAIMY – with the URALS series the defined as “Yamal and Polar Urals long chronologies, plus other shorter ones”. The “other shorter ones” were presumably nearby Schweingruber chronologies – not just Khadyta River. The email:

Date: Fri, 28 Apr 2006
To: philip.brohan
From: Tim Osborn
Subject: Re: Standardisation uncertainty for tree-ring series
Cc: Keith Briffa,simon.tett
Hi Philip,
we have three “groups” of trees:

“SCAND” (which includes the Tornetrask and Finland multi-millennial chronologies, but also some shorter chronologies from the same region). These trees fall mainly within the 3 boxes centred at: 17.5E, 67.5N;22.5E, 67.5N; 27.5E, 67.5N
“URALS” (which includes the Yamal and Polar Urals long chronologies, plus other shorter ones). These fall mainly within these 3 boxes: 52.5E, 67.5N; 62.5E, 62.5N (note this is the only one not at 67.5N); 67.5E, 67.5N

“TAIMYR” (which includes the Taimyr long chronology, plus other shorter ones). These fall mainly within these 4 boxes: 87.5E, 67.5N; 102.5E, 67.5N; 112.5E, 67.5N; 122.5E, 67.5N
We do some analysis at the group scale, and for this we take the JJA temperatures from each box and average to the group scale to obtain a single series from each of SCAND, URALS and TAIMY.

We do some analysis at the overall scale, and for this we take these three group temperature series and average them to get an overall NW Eurasia temperature for boxes with tree chronologies in them.

We did also try using a wider average for the region, including all LAND temperatures from grid boxes within a rectangular region from 12.5E to 127.5E and from 57.5N to 72.5N, but I don’t think it correlated so well against the tree-ring width data (I can’t remember the exact correlations), so we didn’t pursue that.

Does that give you enough information to be going on with? I’d recommend using CRUTEM3 rather than HadCRUT3, because the correlations seem to deteriorate with the inclusion of SST data in some cases — though of course you can look into this yourself.
Cheers
Tim

In March 2007 (780. 1172776463.txt), Osborn again referred to a regional chronology combining Yamal and Polar Urals as being used in a PPT presentation. Osborn noted that revisions to the chronology had made “quite a big change”, thereby getting rid of what had previously been a “higher peak near 1000 AD“:

Here is the old version for you to compare with… the only noticeable difference is for the URALS/YAMAL region, which previously had a higher peak near 1000 AD. Although that was quite a big change, once you average it with the other two series, the overall mean series shows very little difference.
Cheers, Tim

I find the evidence of these emails is hard to reconcile with CRU statements that they had never “considered” updating the Polar Urals chronology, that they had never “considered” adding other chronologies to Yamal to make a regional network and that they had “lacked time” to make a combined Polar Urals/Yamal chronology.

In order for the “inquiries” to properly carry out their obligations, they should, among other things, have obtained the regional chronology referred to in email 1146252894.txt and provided an explanation of why this chronology never appeared. They should also have resolved the apparent contradictions between CRU’s evidence to Muir Russell (and their online statement before Climategate) was that they never “considered” the addition of Schweingruber and other data to make a regional chronology with the evidence of the emails that they had already made such a calculation in April 2006.

I’ll review the conclusions of the inquiries and the reasons for the FOI refusal in following posts.

http://climateaudit.org/2011/04/09/yamal-and-hide-the-decline/