Yamal and the Vaganov Network

As a spin-off from looking at Mann of Oak proxies, I did (what I regard) as a pretty bit of decoding of some measurement data in the Climategate documents.

The Climategate directory documents/briffa-treering-external/stepan/ contains a large number of tree ring measurement files dated July 1996 (with the characteristic suffix .rwl) with 3-character labels,

“ala” “all” “and” “ary” “aya” “bat” …

Interesting as the data might be, it’s hard to do much with it without a lexicon providing locations – and there isn’t such a lexicon in the briffa-treering-external files.

I browsed through the MBH98 proxy rosters when I was looking for oak chronologies, which reminded me that MBH98 had used a network of 61 Vaganov chronologies. No measurement data was available. I’d downloaded Vaganov chronologies from Mann’s University of Virginia website in November 1993 when it was temporarily online. (Shortly afterwards, Mann told Jones in a Climategate email that Scott[Rutherford] had messed up “big-time” in what he had left on the FTP site.)

I remembered that there had been a file in the MBH98 FTP site that had contained lat-longs for the Vaganov network, which had also had 3-character IDs. (The file is once again available in the Climategate documents – look for TREE/VAGABOV/ORIG/sib.dat in mbh98-osborn.zip.) The file sib.dat had 61 entries. They proved to be a perfect match to the *.rwl files at documents/briffa-treering-external/stepan/ .

This little bit of detective work yielded previously unavailable measurement data for MBH98 (measurement data that Mann might not have had access to.)

Of particular interest to me were the data sets in the Yamal area:

V1 V2 V3 V4
1 26 SOB 65.46 66.48
2 27 SOP 65.46 66.48
3 1 SCH 69.17 66.49
4 2 KHA 69.50 67.12
5 3 KHD 69.54 67.07
6 4 JAH 70.58 67.25
7 5 NID 71.40 66.13

Here there is a little additional information from an email in the Climategate documents (documents/briffa-treering-external/ecat/yam9610/ymiss.dat) dated Dec 10, 1996 which stated:

1. As regards individual ring width data of living trees from
Yamal we would remind you that you have them. Stepan gave to you
in England one diskette. There are data for Larix sibirica from
three sites (KHA – from Khadyta river, 67 12’N 69 50’E; JAH –
from Yahody river 67 07’N 69 54’E and POR – from Portsa river
67 27’N 71 00’E) and for Picea obovata from two points (SCH –
Shtshutshya river 66 49’N 69 50’E and KHD – from Khadyta river
67 07’N 69 54’E).

Many CA readers will recall Khadyta River as the Schweingruber site that occasioned considerable controversy in October 2009 just before Climategate (the Oxburgh “report” included Briffa’s online response in its bibliography, but did not discuss any particulars.) The JAH and POR sites were also discussed at the time. (Note that the YAD site – the one with the Dos Equis tree – is not mentioned in the above email.)

The Vaganov version of Khadyta River larch (KHA) included some (but not all) of the Schweingruber cores – the cores that Gavin Schmidt had accused me of finding randomly on the internet.

I did a quick RCS-emulation on the four Yamal measurement data sets in the Vagnov network, shown below. The first three Yamal data sets (kha, khd, sch – one larch and two spruce) have very pronounced divergence problems and all have late 20th century values below the average of the last few centuries. (Even though JAH has an upward trend over the past few centuries and closes above the average of the last few centuries, it also has a divergence problem with the last half 20th being somewhat lower than first half 20th.)

Figure 1. Four Yamal Chronologies from Climategate Documents

CA readers may also recall that, unlike the above chronologies, Briffa’s Yamal chronology has a pronounced HS shape. The figure below show Yamal as it contributes to Kaufman et al 2009 – where it closes at a remarkable 6 sigma. Another accessible version is in the AR4 spaghetti graph that Overpeck (a Kaufman coauthor) included as part of his efforts to deal a “mortal blow” to the myth of an MWP.

The difference between the decline observed in the large-population Schweingruber network and the opposite behavior in Briffa’s Yamal chronology has always been a big problem for me. If most (or even a number of) chronologies in the area decline, then any competent analyst would inquire into the reliability of a chronology showing opposite behavior.

It’s very disappointing that David Hand didn’t assess the problem. It would really be much healthier if inquiries actually inquired into the problems that are at issue.


  1. BillyBob
    Posted Apr 23, 2010 at 4:11 PM | Permalink

    If Yamal WAS a temperature proxy, then one would conclude the 20s/30s were warmer than 2000.

    (Which happens to be what I think but not because of Yamal 🙂 )

  2. Bernie
    Posted Apr 23, 2010 at 4:12 PM | Permalink

    Neat detective work.
    It looks like the 1930’s were anomalously warm in Siberia as they were in North America?

    • Follow the Money
      Posted Apr 23, 2010 at 6:09 PM | Permalink

      Which arguably is favorable evidence the growth ring patterns of some cold-stressed, near-timberline tree species’ may indeed be sensitive to temp change patterns.

      This would be a step forward for science, but harmful to science funding.

  3. Shallow Climate
    Posted Apr 23, 2010 at 4:12 PM | Permalink

    Aha!, another piercing inquiry that this site is famous for. You can’t get that anywhere but here. A statement that deserves to be famous in itself: “It would really be much healthier if inquiries actually inquired into the problems that are at issue.” Amen

  4. mpaul
    Posted Apr 23, 2010 at 4:13 PM | Permalink

    Steve, your memory is a remarkable thing.

    “The difference between the decline observed in the large-population Schweingruber network and the opposite behavior in Briffa’s Yamal chronology has always been a big problem for me.”

    I suspect the ‘trick’ would be to turn a couple of them upside down — its a standard practice you know.

  5. Tony Hansen
    Posted Apr 23, 2010 at 4:25 PM | Permalink

    ‘…It would really be much healthier if inquiries actually inquired into the problems that are at issue’.
    That this point has to be made at all, says much about the ‘science’.

  6. 007
    Posted Apr 23, 2010 at 7:01 PM | Permalink

    I wish Basil Rathbone was alive so if they ever make a movie about Steve, Basil could play him!

  7. Posted Apr 23, 2010 at 8:36 PM | Permalink

    Great to see some new data analysis, Steve.

  8. StuartR
    Posted Apr 24, 2010 at 1:43 AM | Permalink

    I’d downloaded Vaganov chronologies from Mann’s University of Virginia website in November 1993 when it was temporarily online.

    Sorry if I’ve missed something obvious, but is the year right here?

    Steve: Oops, 2003.

  9. Geoff Sherrington
    Posted Apr 24, 2010 at 2:39 AM | Permalink

    Nice work, formidable memory.

    Abundant peoblems reside in reconciling the 4 windows of your fig 1, let alone the broader global questions you have raised before.

    The easy way used to avoid the divergence problem has been to ignore to ignore selected data after 1950. The harder question for readers here is, “What possible mechanisms can explain the divergence?” This is asked in the sense that it’s neater to add new knowledge than to point out errors in the old, even while having respect for the work taken to find the old.

    Personally, my suspicions are that temperature has never been derivable from dendro data except by happy coincidence. It’s not a reliable proxy sometimes, so it’s not reliable ever because you can’t define that ‘sometimes’ in the pre-instrumented past. Is that a cop-out?

  10. jaymam
    Posted Apr 24, 2010 at 4:32 AM | Permalink

    This shows how important it is for all data to be divulged, not merely the data that was used in a published study. But how can we be sure that inconvenient data isn’t just hidden away or deleted?

  11. Mesa
    Posted Apr 24, 2010 at 9:32 AM | Permalink

    Geoff Sherrington – we run across this problem of what’s optimistically called ‘regime change’ in finance all the time. It’s an interesting question as to whether the correlations are spurious or for example, one physical driver (temperature) of some observed growth variable can be dominant in some periods of time drowned out by others during other time periods. It would seem likely intuitively that at least the second is true based on the dynamios of tree growth, although I have no proof of that. I wonder if anyone has a greenhouse big enough and enough time to run controlled tree ring growth experiments? If not, I’m not sure there is much of a conclusion (including error bars) to be drawn from the data as I understand it.

  12. Craig Loehle
    Posted Apr 24, 2010 at 10:19 AM | Permalink

    There are two possibilities for divergence: either something happened to the trees in question in recent decades (local hydrology change or something) or they are bad proxies for temperature. In either case, you have a problem using them. Without knowing which it is and being able to screen such trees out based on conditions in the past as well as the present, you can’t use them (my opinion). Either way, you also can’t use one like Yamal that goes up just because you like that answer. I’m sure someone exists who can lose weight eating just donuts, but we don’t pick them as our representative population.

    • Craig Loehle
      Posted Apr 24, 2010 at 10:21 AM | Permalink

      Oops: OR it has actually gotten colder in Siberia in recent decades, in which case Yamal is wrong.

  13. jlc
    Posted Apr 24, 2010 at 12:21 PM | Permalink

    Steve – you make me proud to be Canadian, even though I’m Australian by birth.

    Hang in there, mate


  14. Robert
    Posted Apr 24, 2010 at 2:12 PM | Permalink

    I think the divergence problem has to be somehow to do with CO2. Which is counterintuitive but it cannot be local conditions across all these regions causing a divergence, that’d be a huge coincidence. It has to be something different which affects all trees at a similar time.

    • tty
      Posted Apr 24, 2010 at 5:45 PM | Permalink

      It doesn’t affect all trees or sites. Divergence is common but far from universal.

    • mpaul
      Posted Apr 26, 2010 at 11:32 AM | Permalink

      Tree rings, as a general matter, show very weak (if any) correlation to temperature. A very small number of magical trees have been discovered that happen to show correlation to temperature during a very brief period. These trees were then specially selected (cherry picked) to be ‘temperature responders’. Later, it was discovered that this “correlation” was ephemeral — like mist on an early morning lake. I don’t think its correct to say that we have a ‘divergence problem’ nor do I think its correct to look for a cause. I think it’s more correct to say that the appropriateness of using tree rings as temperature proxies has not been established and that recent data calls into question the reliance on tree rings in major paleo reconstructions.

  15. Posted Apr 24, 2010 at 8:23 PM | Permalink

    Expanding on Craig’s comment, I note the following: To most environmental factors, organism growth rates — animals, plants, what have you — respond in an “up-down” fashion. That is, there is an optimal value (range) in temperature, pH, etc, corresponding to maximum growth rates, with deviations therefrom causing reductions. Often, but not always, selection adjusts the growth vs. environmental factor curve so that the optimum corresponds roughly to mean environmental conditions. In long-lived species, like slow-growing trees, there is an inevitable time lag — today’s population will be adapted to yesterday’s conditions. So if there is rapid, unidirectional environmental change of sufficient magnitude, one would expect a reduction in growth. The critical point then becomes determining the meaning of “sufficient.”

    According to this, if late twentieth century temperatures have actually been increasing, a “decline” is not unexpected. I say “if,” because, given the degree of “massaging” to which the thermometer record has been subject, the dispassionate observer should at least consider the possibility that late twentieth century warming is artifactual.

    Returning to tree growth rates, one would hope that the plant physiologists have it all worked out. If they have, then the assumption of a positive relation between tree growth and temperature over the requisite range of temperatures and for the species in question is either experimentally justified or it is not. If the physiological studies have not been done — and I’d wager even money that they haven’t — then the tree thermometers on which so much depends are effectively uncalibrated.

    • Craig Loehle
      Posted Apr 24, 2010 at 9:12 PM | Permalink

      The problem, of course, is that you can not do physiological experiments with long-lived trees. In addition, all studies show precip, not just temperature, to be important, and you do not know precip in the past to factor it out. The whole proxy exercise with trees is based on a linear relation between temp & growth which is just unproven and unlikely, especially going very far back in time.

    • James Evans
      Posted Apr 25, 2010 at 4:41 AM | Permalink

      “According to this, if late twentieth century temperatures have actually been increasing, a ‘decline’ is not unexpected.”

      Wouldn’t this imply that optimum conditions for growth for these species was reached in the mid 20th century? How does this square with the hockey stick? If 20th century temps are so unusual, why would these tree species have developed so that their growth is maximal at those unusual temps?

  16. Robert
    Posted Apr 24, 2010 at 11:04 PM | Permalink


    Yeah you have a point, I generalized a bit with that statement. All I was trying to say is that there are a lot of trees with divergence problems but you cannot blame local conditions for each situation. I am inclined myself to believe that it could be a reaction to rapid warming or CO2/Aerosols or something. With respect to Schaffer’s comments, I agree that there are issues with the temperature record but I do think there has been rapid warming since the 60s-80s particularly in high latitudes such as the regions I am from.

    I have myself tried to make a temperature composite for where I am from (Labrador originally) and using 31 stations it actually matches GISS quite well for that region surprisingly… I am not inclined to believe their method is particularly good but I do think that either way there is a rapid warming going on.

    • Barclay E MacDonald
      Posted Apr 25, 2010 at 6:15 AM | Permalink

      Robert, any chance you would like to show us more of what you have found, perhaps your composite? What leads you to believe there has been rapid warming demonstrated in your area of focus? If true, can it possibly be explained by changing ocean currents or indirect El Nino effects or something else? Sorry if I’m being premature. Maybe you’re not ready yet, or it wouldn’t be material to the blog. Oops! I see I am digressing from the topic of the thread. I blame it on the above comments leading me astray:)

      • Robert
        Posted Apr 25, 2010 at 2:20 PM | Permalink

        You are indeed correct that the method is still in its infancy. Maybe in a month or so I will be done with a higher certainty in my results and such, its hard to find time to do things sometimes when you’re working only outside of work hours, i’m sure you can relate.

  17. Chris Wright
    Posted Apr 25, 2010 at 5:54 AM | Permalink

    In the past most of the comment has been confined to the Climategate emails, and very little to the data. It looks like Steve M is now getting to grips with the data. It will be interesting to see whether the data turns out to be more signifivant than the emails. Only time will tell.

    While looking through the files I found lots of data in directories whose names include the word ‘censured’. To anyone who has read the history of the hockey stick this should immediately ring the alarm bells. I’m amazed that there has – as far as I know – been little or no comment on this. Would Steve M like to comment?

  18. stephen richards
    Posted Apr 25, 2010 at 6:18 AM | Permalink

    There are some things we can say for certain about plant(almost)and their relation to growing conditions. They adapt.

    However, certain types of plant adapt to their environment more readily than others. It appears from the fossil record that trees may adapt more slowly than for instance legumes and that this could be down to the fertilisation process, perhaps, or longevity. What we can say for certain, as vegetable growers is that warm and averagely damp is best. Warm and too damp is bad, cold and dry is bad, cold and wet is bad; cold and dry is hopeless as is warm and dry. Put this into an equation and what do get? You get that temperature is NOT mutually exclusive. It virtually has to be impossible to separate the warm signal from the precipitation signal even with stats, unless you have a suitable calibration parametre which will allow you to isolate the precipitation. I don’t see one back to the year dot.

    • Dave L.
      Posted Apr 25, 2010 at 7:06 AM | Permalink


      I cultivate thousands of flower bulbs, and I fully agree with you. It is not possible to analyze the combinations of temperature and moisture that you list because the data is not available for the actual locations of the trees (microclimates), and another important aspect is the occurrence of a brief late significant freeze in spring (I have no fruit on my trees this year because of such a late freeze).

      Another very important contribution that is not evaluated: nutrients, in particular the crowding together of individual trees — too much competition from crowding and growth is stunted, but the degree of crowding versus stunting is not a linear relationship. I can tell you from personal observations, that when stunting occurs, the overall effects upon individual growing parts are definitely not uniform (at least in flower bulbs); some parts show more pronounced effects than other parts.

  19. Mesa
    Posted Apr 25, 2010 at 9:34 AM | Permalink

    I suspect that the paleo argument would be that temperature is a somehow a universal observable variable across the globe due to CO2 increases, while things like precipitation and crowding, nutrients etc would “average out”. I think what has really happened is basically an “averaging out” of everything (as this blog has pointed out may times), coupled with careful selection and combination of proxies in unusually “creative” ways to claim evidence of warming recently. It’s pretty obvious from say the satellite record that temperature changes are not well correlated enough across the globe to be claimed to be universal, at least to the level of resolution we are talking about here, say 1 degree C. I’d be interested if there is a counter-argument paleos might make.

  20. LearDog
    Posted Apr 25, 2010 at 10:18 AM | Permalink

    Steve, Geoff, Craig –

    love the analysis and comments (‘losing weight by eating donuts’ ha ha ha! ). Of course all you’re doing is merely indicting an entire wing of ‘science’ that has kind of gotten away from reality.

    Honestly can’t expect the dendrochronologists to face such difficult questions, they’re human after all. Best for them to ignore the elephant in the room (la la la la). That’s why they’ve been forced to resort to elaborate and unscientific tricks to keep the edifice in place:
    a) ‘hiding the decline’,
    b) forcing the densities to match, or
    c) selecting the “well-behaved” trees to get around the ‘divergence’ issue.

    Otherwise – they would have to squarely address the fact that their chosen field isn’t really science.


  21. DocMartyn
    Posted Apr 25, 2010 at 7:07 PM | Permalink

    “Craig Loehle

    The problem, of course, is that you can not do physiological experiments with long-lived trees.”

    I must respectfully disagree, the experiments have been done.
    In Parks and Arboretums all around the world are tress that were placed there some decades ago; where they were moved from and when is known. There are many hundreds of transplanted tress in Central Park NY alone.
    It would be quite easy to look at the tree rings of moved tress at Kew Gardens, outside London.

  22. john
    Posted Apr 26, 2010 at 5:18 PM | Permalink

    I sometimes think that Steve McIntyre’s posts are somewhat obscure . I recently sent an e-mail to a third party (see below) trying to clarify what he said in the Yamal post of April 23. Do I give a reasonably accurate synopsis of what he wrote there?

    Besides e-mails, the climategate files include data files, obscurely labled, that might or might not be related to published results. Steve McIntyre has performed some impressive detective work in identifying files relating to the Yamal chronology. The published work based on the Yamal chronology shows a recent six standard deviation movement in temperature upwards from the long run fluctuations about the average. The climategate files, that he suggests underlies the published Yamal chronology, are dramatically different and taken together show a decline in recent years.

    Graphs of the comparisons can be found at:


    McIntyre is asking for an explanation for the discrepency which he thinks the Oxburgh inquirey could have also demanded.

  23. John Blake
    Posted Apr 28, 2010 at 7:13 PM | Permalink

    Given the Russian aerial photo of larch thickets closely tracking river margins, correlating tree-ring patterns with water-tables would be an interesting exercise. Are any requisite hydrological data historically available from this area?

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