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« Media reactions to Yamal | Main | Zippideedoodah »

The Yamal implosion

There is a great deal of excitement among climate sceptics over Steve McIntyre's recent posting on Yamal. Several people have asked me to do a layman's guide to the story in the manner of Caspar and the Jesus paper. Here it is.

The story of Michael Mann's Hockey Stick reconstruction, its statistical bias and the influence of the bristlecone pines is well known. McIntyre's research into the other reconstructions has received less publicity, however. The story of the Yamal chronology may change that.

The bristlecone pines that created the shape of the Hockey Stick graph are used in nearly every millennial temperature reconstruction around today, but there are also a handful of other tree ring series that are nearly as common and just as influential on the results. Back at the start of McIntyre's research into the area of paleoclimate, one of the most significant of these was called Polar Urals, a chronology first published by Keith Briffa of the Climate Research Unit (CRU) at the University of East Anglia. At the time, it was used in pretty much every temperature reconstruction around. In his paper, Briffa made the startling claim that the coldest year of the millennium was AD 1032, a statement that, if true, would have completely overturned the idea of the Medieval Warm Period.  It is not hard to see why paleoclimatologists found the series so alluring.

Keith BriffaSome of McIntyre's research into Polar Urals deserves a story in its own right, but it is one that will have to wait for another day. We can pick up the narrative again in 2005, when McIntyre discovered that an update to the Polar Urals series had been collected in 1999. Through a contact he was able to obtain a copy of the revised series. Remarkably, in the update the eleventh century appeared to be much warmer than in the original - in fact it was higher even than the twentieth century. This must have been a severe blow to paleoclimatologists, a supposition that is borne out by what happened next, or rather what didn't: the update to the Polar Urals was not published, it was not archived and it was almost never seen again.

With Polar Urals now unusable, paleclimatologists had a pressing need for a hockey stick shaped replacement and a solution appeared in the nick of time in the shape of a series from the nearby location of Yamal.

The Yamal data had been collected by a pair of Russian scientists, Hantemirov and Shiyatov, and was published in 2002. In their version of the data, Yamal had little by way of a twentieth century trend. Strangely though, Briffa's version, which had made it into print before even the Russians', was somewhat different. While it was very similar to the Russians' version for most of the length of the record, Briffa's verison had a sharp uptick at the end of the twentieth century -- another hockey stick, made almost to order to meet the requirements of the paleoclimate community.  Certainly, after its first appearance in Briffa's 2000 paper in Quaternary Science Reviews, this version of Yamal was seized upon by climatologists, appearing again and again in temperature reconstructions; it became virtually ubiquitous in the field: apart from Briffa 2000, it also contributed to the reconstructions in Mann and Jones 2003, Jones and Mann 2004, Moberg et al 2005, D'Arrigo et al 2006, Osborn and Briffa 2006 and Hegerl et al 2007, among others.

When McIntyre started to look at the Osborn and Briffa paper in 2006, he quickly ran into the problem of the Yamal chronology: he needed to understand exactly how the difference between the Briffa and Hantemirov versions of Yamal had arisen. McIntyre therefore wrote to the Englishman asking for the original tree ring measurements involved. When Briffa refused, McIntyre wrote to Science, who had published the new paper, pointing out that, since it was now six years since Briffa had originally published his version of the chronology, there could be no reason for withholding the underlying data. After some deliberation, the editors at Science declined the request, deciding that Briffa did not have to publish anything more as he had merely re-used data from an earlier study. McIntyre should, they advised, approach the author of the earlier study, that author being, of course, Briffa himself. Wearily, McIntyre wrote to Briffa again, this time in his capacity as author of the original study in Quaternary Science Reviews and he was, as expected, turned down flat.

That was how the the investigation of the Yamal series stood for the next two years until, in July 2008, a new Briffa paper appeared in the pages of the Philosophical Transactions of the Royal Society B, the Royal Society's journal for the biological sciences. The new paper discussed five Eurasian tree ring datasets, which, in fairly standard Hockey Team fashion, were unarchived and therefore not succeptible to detailed analysis. Among these five were Yamal and the equally notorious Tornetrask chronology. McIntyre observed that the only series with a strikingly anomolous twentieth century was Yamal. It was frustratingly therefore that he had still not managed to obtain Briffa's measurement data. It appeared that he was going to hit another dead end. However, in the comments to his article on the new paper, a possible way forward presented itself. A reader pointed out that the Royal Society had what appeared to be a fairly clear and robust policy on data availability:

As a condition of acceptance authors agree to honour any reasonable request by other researchers for materials, methods, or data necessary to verify the conclusion of the article...Supplementary data up to 10 Mb is placed on the Society's website free of charge and is publicly accessible. Large datasets must be deposited in a recognised public domain database by the author prior to submission. The accession number should be provided for inclusion in the published article.

Having had his requests rejected by every other journal he had approached, McIntyre had no great expectations that the Royal Society would be any different, but there was no harm in trying and he duly sent off an email pointing out that Briffa had failed to meet the Society's requirement of archiving his data prior to submission and that the editors had failed to check that Briffa had done so. The reply, to McIntyre's surprise, was very encouraging:

We take matters like this very seriously and I am sorry that this was not picked up in the publishing process.

Was the Royal Society, in a striking contrast to every other journal in the field, about to enforce its own data availability policy? Had Briffa made a fatal mistake?

Summer gave way to autumn and as October drew to a close, McIntyre had still heard nothing from the Royal Society. However, in response to some further enquiries, the journal sent McIntyre some more encouraging news -- Briffa would be producing most of his data, although not immediately. Most of it would be available by the end of the year, with the remainder to follow in early 2009.

The first batch of data appeared on schedule in the dying days of 2008 and it was something of a disappointment. The Yamal data, as might have been expected, was to be archived with the second batch, so there would be a further delay before the real action could start. Meanwhile, however, McIntyre could begin to look at what Briffa had done elsewhere. It was not to be plain sailing. For a start, Briffa had archived data in an obsolete data format, last used in the era of punch-cards. This was inconvenient, and apparently deliberately so, but it was not an insurmountable problem -- with a little work, McIntyre was able to move ahead with his analysis. Briffa had also thrown a rather larger spanner in the works though: while he had archived the tree ring measurements, he had not supplied any metadata to go with it -- in other words there was no information about where the measurements had come from. All there was was a tree number and the measurements that went with it. However, McIntyre was well used to this kind of behaviour from climatologists and he had some techniques at hand for filling in some of the gaps. Climate Audit postings on the findings followed in fairly short order, some of which were quite intriguing. There was, however, no smoking gun.

There followed a long hiatus, with no word from the Royal Society or from Briffa. McIntyre would occasionally visit Briffa's web page at the CRU website to see if anything new had appeared, but to no avail. Eventually, though, Briffa's hand was forced, and in late September 2009, a reader pointed out to McIntyre that the remaining data was now available. It had been quietly posted to Briffa's webpage, without announcement or the courtesy of an email to Mcintyre. It was nearly ten years since the initial publication of Yamal and three years since McIntyre had requested the measurement data from Briffa. Now at last some of the questions could be answered.

When McIntyre started to look at the numbers it was clear that there were going to be the usual problems with a lack of metadata, but there was more than just this. In typical climate science fashion, just scratching at the surface of the Briffa archive raised as many questions as it answered. Why did Briffa only have half the number of cores covering the Medieval Warm Period that the Russian had reported? And why were there so few cores in Briffa's twentieth century? By 1988 there were only 12 cores used, an amazingly small number in what should have been the part of the record when it was easiest to obtain data. By 1990 the count was only ten, dropping still further to just five in 1995. Without an explanation of how the selection of this sample of the available data had been performed, the suspicion of `cherrypicking' would linger over the study, although it is true to say that Hantemirov also had very few cores in the equivalent period, so it is possible that this selection had been due to the Russian and not Briffa.

The lack of twentieth century data was still more remarkable when the Yamal chronology was compared to the Polar Urals series, to which it was now apparently preferred. The ten or twelve cores used in Yamal was around half the number available at Polar Urals, which should presumably therefore have been considered the more reliable. Why then had climatologists almost all preferred to use Yamal? Could it be because it had a hockey stick shape?

None of these questions was likely to be answered without an answer to the question of which trees came from which locations. Hantemirov had made it clear in his paper that the data had been collected over a wide area - Yamal was an expanse of river valleys rather than a single location. Knowing exactly which trees came from where might well throw some light onto the question of why Briffa's reconstruction had a hockey stick shape but Hantemirov's didn't.

As so often in McIntyre's work, the clue that unlocked the mystery came from a rather unexpected source. At the same time as archiving the Yamal data, Briffa had recorded the numbers for another site discussed in his Royal Society paper: Taimyr. Taimyr had, like Yamal, also emerged in Briffa's Quaternary Science Reviews paper in 2000. However, in the Royal Society paper, Briffa had made major changes, merging Taimyr with another site, Bol'shoi Avam, located no less than 400 kilometres away. While the original Taimyr site had something of a divergence problem, with narrowing ring widths implying cooler temperatures, the new composite site of Avam--Taimyr had a rather warmer twentieth century and a cooler Medieval Warm Period. The effect of this curious blending of datasets was therefore, as so often with paleoclimate adjustments, to produce a warming trend. This however, was not what was interesting McIntyre. What was odd about Avam--Taimyr was that the series seemed to have more tree cores recorded than had been reported in the two papers on which it was based. So it looked as if something else had been merged in as well. But what?

With no metadata archived for Avam-Taimyr either, McIntyre had another puzzle to occupy him, but in fact the results were quick to emerge. The Avam data was collected in 2003, but Taimyr only had numbers going up to 1996. Similarly, the Taimyr trees were older, with dates going back to the ninth century. It was therefore possible to make a tentative split of the data by dividing the cores into those finishing after 2000 and those finishing before. This was a good first cut, but the approach assigned 107 cores to Avam, which was more than reported in the original paper. This seemed to confirm the impression that there was something else in the dataset.

At the same time, McIntyre's rough cut approach assigned 103 cores to Taimyr, a number which meant that there were still over 100 cores still unallocated. The only way to resolve this conundrum was by a brute force technique of comparing the tree identification numbers in the dataset to tree ring data in the archives. In this way, McIntyre was finally able to work out the provenance of at least some of the data.

Forty-two of the cores turned out to be from a location called Balschaya Kamenka, some 400 km from Taimyr. The data had been collected by the Swiss researcher, Fritz Schweingruber. The fact that the use of Schweingruber's data had not been reported by Briffa was odd in itself, but what intrigued McIntyre was why Briffa had used Balschaya Kamenka and not any of the other Schweingruber sites in the area. Several of these were much closer to Taimyr -- Aykali River was one example, and another, Novaja Rieja, was almost next door.

By this point then, McIntyre knew that Briffa's version of Yamal was very short of twentieth century data, having used just a selection of the available cores, although the grounds on which this selection had been made was not clear. It was also obvious that there was a great deal of alternative data available from the region, Briffa having been happy to supplement Taimyr with data from other locations such as Avam and Balschaya Kamenka. Why then had he not supplemented Yamal in a similar way, in order to bring the number of cores up to an acceptable level?

The reasoning behind Briffa's subsample selection may have been a mystery, but with the other information McIntyre had gleaned, it was still possible to perform some tests on its validity. This could be done by performing a simple sensitivity test, replacing the twelve cores that Briffa had used for the modern sections of Yamal with some of the other available data. Sure enough, there was a suitable Schweingruber series called Khadyta River close by to Yamal, and with 34 cores, it represented a much more reliable basis for reconstructing temperatures.

McIntyre therefore prepared a revised dataset, replacing Briffa's selected 12 cores with the 34 from Khadyta River. The revised chronology was simply staggering. The sharp uptick in the series at the end of the twentieth century had vanished, leaving a twentieth century apparently without a significant trend. The blade of the Yamal hockey stick, used in so many of those temperature reconstructions that the IPCC said validated Michael Mann's work, was gone.


[Updated 30/9/09 to correct minor dating issue. Also removed the reference to KB's illness which is apparently genuine]


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References (10)

References allow you to track sources for this article, as well as articles that were written in response to this article.
  • Response
    - Bishop Hill blog - The Yamal implosion There is a great deal of excitement among climate sceptics over Steve McIntyre's recent posting on Yamal. Several people have asked me to do a layman's guide to the story in...
  • Response
    "Bishop Hill" has done it again. He's posted another tale, understandable by laymen, of a scientific detective at work. It's similar to his classic Caspar and the Jesus paper. Nowadays, alas, the job of a truth-seeker is often to uncover the deceits of scientists themselves... (It's probably hard for most...
  • Response
    Cobb does a fine job summarizing a scientific scandal about, what else, human-induced global warming. Seems a goodly portion of the worldwide scare's convincing data was cherry picked:"Twelve trees whose growth rings were the basis of the conclusions that have...
  • Response
  • Response
    A. W. Montford posts a great list of 33 of the more outrageous emails from the Climatic Research Institute over at Bishop Hill Blog. Here are the first ten: Climate cuttings 33Welcome Instapundit readers! Hope this is useful for you....
  • Response
    For those of you who don’t know of the blog Bishop Hill, let me say that he is a succinct and careful writer who has earned praise from many (including myself and Steve McIntyre) in taking a difficult niche subject such as the Hockey Stick and paleo
  • Response
    John Gormley Live and SDA - doing the job the CBC won't do! Welcome JGL listeners: some links to bring you up to speed. Because if you've been relying on your trusty network newsguys to deliver the goods, you're being...
  • Response
    [...]- Bishop Hill blog - The Yamal implosion[...]
  • Response
    Response: Rocco Haller
    Thanks again for the blog. Great.
  • Response
    Response: Dead Ringer
    In a prelude to Climategate, an East Anglia global warmist withheld critical data on tree ring growth. We now know why.

Reader Comments (147)

I think this is a great summation. It is a very technical story, I tried to do a 'peer' review of spotting obvious mistakes in this post, but its late and I am sure I am too close in sympathy with the authors Pov, I would hope that later commenters will be more testing ;)

Sep 29, 2009 at 11:18 PM | Unregistered CommenterStuartR

I assumed your reference to comment #7 was a typo. I didn't realize you thought Briffa was avoiding comments. Perhaps he is just ill.

Sep 30, 2009 at 1:11 AM | Unregistered CommenterMikeN

I'm sure you are aware, but the reader who suggested to Steve McIntyre whether he tried getting Royal Society to make Briffa archive was one Bishop Hill.

It's like how the author of the Mahabharata was himself a character in the story.

Sep 30, 2009 at 1:13 AM | Unregistered CommenterMikeN

Fantastic, thanks for your efforts.

"This week’s claims by Steve McInyre that scientists associated with the UK Meteorology Bureau have been less than diligent are serious and suggest some of the most defended building blocks of the case for anthropogenic global warming are based on the indefensible when the methodology is laid bare...It is indeed time leading scientists at the Climate Research Centre associated with the UK Meteorological Bureau explain how Mr McIntyre is in error or resign. "

See more at

Sep 30, 2009 at 1:18 AM | Unregistered CommenterAyrdale

The paragraph with this beginning:

"The Yamal data had been collected by a pair of Russian scientists, Hantemirov and Shiyatov, back in 2002. "

has some issues with dates. Essentially, the data couldn't have been collected "back in 2002" because it was already published - by Briffa - in 2000. I think the paragraph is correct if the start reads thusly:

"The Yamal data had been collected by a pair of Russian scientists, Hantemirov and Shiyatov, at some time prior to 2000. Their first publication of the data was in 2002."

Sep 30, 2009 at 1:59 AM | Unregistered CommenterAlan S. Blue

a tip of the mitre to yah, yer grace, and maybe a nomination to arch-bishop. I have been following this story a long time and your narrative is far better than anything I could have produced. This is a story that needs deseminating, especially in the UK where half the conspriacy dwells... you people actually have a more flexible and responsive system than we Americans have... corner one of your back-benchers and fill him with delusions of Disreali-hood and he may decide to speak. Here in the colonies... my congressional delegation can't be bothered to read what is placed before them before voting.

How complex is the issue here in the States? We still allow ordinary citizens to own conceable firearms. The law says you should be issued either a permit or receive a denial in 6-8 weeks. My application has just past 16 weeks and my friendly local PD says the backlog may be 8 months.

Sep 30, 2009 at 5:14 AM | Unregistered CommenterRobert E. Phelan

yeah, it would help if colonials could spell..

Sep 30, 2009 at 5:15 AM | Unregistered CommenterRobert E. Phelan


Good spot. I'll fix it.

Sep 30, 2009 at 5:24 AM | Registered CommenterBishop Hill


Modesty prevents me from making too much emphasis on my part in the investigation....

You are right to raise the possibility of Briffa genuinely being ill. It would be quite a coincidence, but it is not a possibility that can be ruled out. To me it looks like he's hiding.

Sep 30, 2009 at 5:30 AM | Registered CommenterBishop Hill

Bishop, thanks for the engaging and interesting narrative. Yes, the role and incentive from the "reader" was very instrumental. I've been told that Briffa has a serious kidney illness that arose in the summer. I suggest that you edit both the post and references accordingly. Cheers, Steve

Sep 30, 2009 at 6:08 AM | Unregistered CommenterSteve McIntyre

Excellent rendering of the saga, which is lost in the spaghetti noise of the CA postings. I stumbled upon the story there late and it was like trying to understand the storyline and characters from the last 5 pages of a manuscript.

I read on WUWT a post from Anthony Watts saying that he has it on good authority that Briffa is genuinely ill with a serious kidney illness. But given the enormity of the deception raised by him and Jones, I still harbour your suspicions. If true it will be the only genuine thing about this whole sordid drama.

Sep 30, 2009 at 6:25 AM | Unregistered CommenterRichard

Steve, Richard. I hadn't seen that. I've amended accordingly.

Sep 30, 2009 at 6:34 AM | Registered CommenterBishop Hill

One part of the story that didn't get told. Early on, both Mann and Rutherford were very forthcoming with their data when Steve asked. What if they had ignored him?

Sep 30, 2009 at 7:41 AM | Unregistered CommenterMikeN

Where does this put the hockey stick theory?

Sep 30, 2009 at 7:48 AM | Unregistered CommenterWilliam Duffy

I think you are mixing up H&S and Esper in this post.

It is almost certain that Briffa 2000 and H&S both use the same Yamal tree cores for the earlier parts of their reconstruction (pre 1000AD ish) but Briffa uses a lot more in the later stages (1000AD and on) except that th enumber declines significantly in the post 1900 timeframe.

Also Steve M guesstimated the 400km distances. I plotted the relevant points on a map which may help - Avam, Taymir etc, is the green triangle, Yamal the pink square and point.

Sep 30, 2009 at 8:20 AM | Unregistered CommenterFrancisT

Great report.

Can I suggest that you put Episode 1 and 2 together (Hockey stick and son of Hockey stick) and write a paragraph or two to put it into its wider context, then have that available as one link. In that way we can send it to those who should know about this, and they don't need to have extensive prior knowledge to understand what is going on.

Incidentally, can I endorse the comments about UK meteorology. I have some dealings with the Met office/Hadley centre and they have gaping gaps in their knowledge on;
a) Historical context
b) The effects of the various currents
c) The jet stream,
d) The impact of melting glaciers on sea levels.


Sep 30, 2009 at 8:40 AM | Unregistered Commentertonyb

That made very good reading. It was nice to see it layed out clearly.

It is sad to see the corruption that has so affected good science..... Briffa should have made all his data available for scrutiny upon first publication, any Good scientist would.

Sep 30, 2009 at 8:51 AM | Unregistered CommenterJ.Hansford


Help me here. Why do you think I've muddled Esper and H&S?

Also, are you saying 400km is wrong?

Sorry to be so brief. I'm in the middle of a work crisis as well as doing this.

Sep 30, 2009 at 8:54 AM | Registered CommenterBishop Hill

Excellent post Bish! You have stirred something rather big here. I agree with Tonyb about linking the tow parts of the story. Well done, & nice to have you back after a short absense.

Sep 30, 2009 at 8:56 AM | Unregistered CommenterAlan the Brit


You should write a book.

Think about the plot elements. A sinister international organisation intent on world domination, shifty scientists in the pay of the sinister organisation, corrupt and venal politicians and a compliant mass media asleep at the wheel while their industry heads off a cliff. These are confronted by a plucky scientist (Steve McIntyre) insisting on the truth aided and abetted by a Communicator and Volunteer mobiliser extraordinaire (Anthony Watts). And all of this brought to the masses over the heads of the compliant media by a handsome (I am presuming you are handsome) archbishop (forgive the promotion in rank) who plays a character that is Woodwards and Bernstein rolled into one.

It even has a mole in the Hadley Center who released the climate records to McIntyre.

Think about the film that will follow and who might play your good self.

Here is how you get it pubslished without too much effort.

There is a website called where you can post up a book or parts of it. People then read it and rate it. The top ones get looked at, both by Harper Collins who own the site, and every other publisher in the world.

All you need do is post up this paper and Jesus and The Casper paper as two chapters. All your fans, and Anthony's and Steve's, will all then log in create accounts and rate your book to put it at the top of the best seller lists. Roll on the bidding war.

So finally. I think your readers here should suggest a name for the book.

My suggestion is DEEP CLIMATE after the mole at Hadley.

Sep 30, 2009 at 9:06 AM | Unregistered Commenter40 shades of green

Brilliant analysis. I generally check your blog after WUWT, CA, Climate Depot & Icecap, because that's the sequence of my bookmarks, but Antony's referral was just too inviting to resist.

Thanks for all your efforts to repel the AGW juggernaut.



Sep 30, 2009 at 9:10 AM | Unregistered CommenterPerry

Another excellent post. Even those of a non-scientific bent can understand this and see that the scientific methodology has been seriously abused by the climatology community.

Sep 30, 2009 at 9:23 AM | Unregistered CommenterPhillip Bratby

Bishop, thank you very much for responding to mine and others' appeals for a layman's summary of this affair. If we (in the western world) still have any journalist interested in doing actual journalism, he or she would jump on a story like this.

Sadly, nowadays it seems that their primary objective is to be a tool of the state, rather than its loudest critic.

Sep 30, 2009 at 9:25 AM | Unregistered CommenterBob Fleming

Thank you for this lucid description. I am a laymen who has been trying to follow this issue and wasn't sure that I had a good enough grasp of what had been going on, something I now posses and will use to direct others to your site.
Thanks again

Sep 30, 2009 at 9:37 AM | Unregistered CommenterTony Armstrong

I will repeat some of a post I made at CA here.

I agree that extending backwards from multiple overlapped records must produce greater deviations from reality.
I agree that a single tree ring record can deviate once away from the matched record.

However, thinking as an engineer trying to find an accurate reading of for example a time series of a voltage supply to a building monitored with inaccurate chart recorders over various lengths of cable (= added noise). if one recorder is known to have been calibrated (to national standards) over recent part of that record, then I would look at the other recorders over this calibrated period and throw out all the outlier readings (they are wrong now, and I do not know if they were ever correct so there is no reason to include them in my determination. Some of the more accurate recorders may have read high before the calibrated range and some may have read low. Some will be recording significant noise compared to the majority and so these could be ignored if sufficient others remain to determine this fact. I would then average the remainder and suggest that this average record is the most likely record of voltage.
As a statistician are you suggesting that all recorder outputs should be averaged including those reading zero and those reading full scale and those whose readings deviate grossly from the mean.
This seems wrong and certainly will give a invalid result. Am I wrong?

But then we need to look at the tree sampling.
Were the trees sampled totally at random - trees in water, trees in bogs, trees scraping by on a solid rock, trees near to death, young trees etc?
Were they at the tree line or sea level?
Were they all the same "make"?

I would suggest that the actual sampling was not random. Altitude, health, species, etc. are all non randomly chosen (cherry picked)

If this is the case what is the point suggesting that they should not be further chosen to best represent temperature?
what would be the point for example choosing a tree that fell over during its life but continued to grow with diminished root function?
What would be the point in chosing a tree with growth limited by water/nutrients.
What would be the point in including a tree 100skm further north than the rest?
Would your statistical methods require that these be included in the sequence?
With tree rings you are not blindly trying to extract information from random data. You already have a VALID LOCAL temperature record to compare against. Any thing that does not match this is not valid data!

Sep 30, 2009 at 9:49 AM | Unregistered Commenterthefordprefect

Appologies for this
Tom P: on WUWT has repeated McIntyres R code but included the trees under scrutiny. The plot he obtains is very hockeystick-like. Aparently the excluded trees have more recent data and stand alone in that area.

Is it wrong to still exclude them? Or are they a valid set of data which should be included?

Sep 30, 2009 at 9:54 AM | Unregistered Commenterthefordprefect

I have been reading the original postings on CA for some time and for the layman it's seriously heavy stuff. You have once again brilliantly rendered it comprehensible not only to a non-specialist follower of this issue but to anyone coming to it for the first time.

Congratulations not only for this but also (something I had not suspected previously) for pointing out to Steve McIntyre that the data had now to be accessible.


Sep 30, 2009 at 10:02 AM | Unregistered CommenterRon

Thanks for a great summary of the Yamal issues.

Sep 30, 2009 at 10:38 AM | Unregistered CommenterMattW

I've been following Steve McIntyre's AGW rebuttals for some time but cannot understand some of the maths involved. I'm an archaeologist, not a statitician. I've just read Caspar and the Jesus Paper followed by this latest post on the abuse of the Yamal data set. You explain things so clearly without the use of mathematical formulae and for that I thank you. I can now fully understand how Steve McIntyre trashed the Hockey Stick graph and continues to erode the pernicious warmist "consensus".

You have a new communicant, Your Grace.

Sep 30, 2009 at 10:49 AM | Unregistered CommenterUK Sceptic

theFordPrefect, I don't know if you know, but Jeff ID has looked at Tom P's work here:

Sep 30, 2009 at 11:31 AM | Unregistered CommenterStuartR


Excellent description of the sad adventure. I too try to make the information more "layman friendly" on my blog. I frequently stop by, but often my visits are little more than "drive by's". Sadly my extended vacation in Afghanistan is cutting into my writing/blogging/reasearch time. I'm looking forward to being able to spend more time AGW issues when my time here is done. But yours is one of my favorite sites to read.

Sep 30, 2009 at 11:32 AM | Unregistered CommenterJLKrueger

Thanks, and thanks again for a clear statement of the story so far in plain language. This is an enormous help for the intelligent layperson to follow and understand the situation. Much is at stake here, not least the provenance and honest practices of science, which are threatened by this sort of shoddy (possibly dishonest) practice. Minds are like parachutes, they ony work if they are open. Well done indeed both to Bishop Hills and to the tireless Steve McKintyre..

Sep 30, 2009 at 11:34 AM | Unregistered CommenterRobin

So has the BBC been in touch to interview Mr M about this?

Or is that a bit too much to expect, given al beebs almost zealous pro-global warming (tm) coverage over the years?


Sep 30, 2009 at 11:40 AM | Unregistered CommenterMailman

Thanks for the trouble you took to write that clear account. James Delingpole has picked this up at

Sep 30, 2009 at 11:45 AM | Unregistered CommenterJohn Page

A clearly explained post, Bishop.
The prevalence of not letting mere data get in the way of a good theory seems to be widespread.

Sep 30, 2009 at 11:54 AM | Unregistered CommenterAlan Love

Thanks for a very good description of this debacle, which makes it easy for the layman to see what the central issues are.

Being a retired hydroponics famer, I have always distrusted tree-ring data as a proxy for temperature, as I know from experience many, many other factors can and do effect plant growth. Some of these vary over time, like availability of nutrients, abundance/depletion of trace elements, changes to soil drainage effecting water to the roots etc. etc.

Beats me how anyone can claim to be accurate to a fraction of a degree using these types of proxy.

Let hope the media pick up on this one, as it is time to expose what's really going on with this AGW scam.

Thanks again, Bishop, for producing a good Blog - I'll be back...

Sep 30, 2009 at 11:58 AM | Unregistered CommenterTenuc

Distances in Avam Taymir.

My google map tells me that Taymir Avam = 205 miles (325km) approx, Avam - Kamenka 60m/100km and Taymit - Kamenka 160 miles (260 km)

All of these distances are less than 400km.

However, more importantly, map also show very clearly that three Schweingruber sites - Kotuy, Kotuykan and Novoja Rieka are closer to Taymir, particularly the latter one.

The H&S / Esper thing.

Quoting from Ross' comment at CA:

In the 1990s, Schweingruber obtained new Polar Urals data with more securely-dated cores for the MWP. Neither Briffa nor Schweingruber published a new Polar Urals chronology using this data. An updated chronology with this data would have yielded a very different picture, namely a warm medieval era and no anomalous 20th century. Rather than using the updated Polar Urals series, Briffa calculated a new chronology from Yamal - one which had an enormous hockey stick shape. After its publication, in virtually every study, Hockey Team members dropped Polar Urals altogether and substituted Briffa's Yamal series in its place. PS: The exception to this pattern was Esper et al (Science) 2002, which used the combined Polar Urals data. But Esper refused to provide his data. Steve got it in 2006 after extensive quasi-litigation with Science (over 30 email requests and demands).

If you look at some of the older CA posts (e.g. ones near here) you see that the effort is to compare Esper with Briffa.

H&S seems to only be mentioned in the first of the recent Yamal posts where it is introduced as follows after some comments about Esper:

Reconciliation of the disparate Yamal-Polar Urals Update (and other such regional reconciliations) seems to me like the first order of business if multiproxy reconstructions are to advance. As an analyst in Toronto, I can comment on the differences, but am not in a position to resolve them. Such reconciliations are properly the obligation and responsibility of the field scientists involved. Unfortunately, to date, people in the field have not honored this responsibility and, to an outside observer, seem to have done no more than pick the version (Yamal) that suits their bias.


First, to clear a little underbrush. There is one other version of these series that readers may encounter: Hantemirov and Shiyatov archived a Yamal reconstruction at NCDC that has no hockey stick blade whatever. This version was promoted by a commenter (Lucy Skywalker) at Jeff Id's as being a priori more valid than Briffa's. Although the Hantemirov and Briffa chronologies have a very different visual appearance (especially the non_HSness of the Hantemirov version), there is an extremely high correlation between the very different looking Hantemirov-Shiyatov and Briffa Yamal chronologies. (If you regress the Briffa recon against the Hantemirov recon for the pre-1800 version, you get a huge r^2 of 0.81). The two series clearly have the same raw material.

I interpret this to mean that Steve was more concerned withthe Esper/Briffa differences than the H&S/Briffa differences although I admit that posts like and are less clear cut.

Its probably a stormina teacup, the point is that neither H&S nor Esper show a hockeystick but Briffa's reprocessing of the H&S data does. And despite the extistance of both Esper and H&S since 2002 most papers seem to have prefered to use the Briffa result even if some of them actually credit H&S.

Sep 30, 2009 at 12:55 PM | Unregistered CommenterFrancisT

Thanks Bishop Hill for posting this. I think it makes it much easier for the average person (like myself) to understand this issue.

Sep 30, 2009 at 2:36 PM | Unregistered CommenterMark

QUoting Robert E. Phelan:

"yeah, it would help if colonials could spell."


If we run across any we'll pass that along.

Sep 30, 2009 at 2:43 PM | Unregistered CommenterWestHoustonGeo

From my own blog :

"Also, I owe a debt of gratitude to 'Bishop Hill', an intelligent blogger with the great gift of 'translating' and condensing scientific complexities into plain English for the benefit of dummies like me."

Says it all, really!

Sep 30, 2009 at 2:58 PM | Unregistered CommenterDavid Duff

Thank's for making this more understandable !!!

Sep 30, 2009 at 3:04 PM | Unregistered CommenterMatthew W

Thanks, Bishop. It's great to read an exposition of this subject written by a native speaker of the language. I hope that some of us will be able to get your work even more widely published. Raise a glass and toast "confusion to the enemy".

Sep 30, 2009 at 3:15 PM | Unregistered CommenterDon S.

Thanks for the activity report. It is obvious that enthusiasm to work with the Bishop is missing along with tree rings.

Sep 30, 2009 at 3:18 PM | Unregistered Commenterhenry chance

I just want to thank you for breaking down the process that Mr. McIntyre went through to put the stake through the abomination referred to as "the Hockey Stick."

Sep 30, 2009 at 4:22 PM | Unregistered CommenterKevin S


"With tree rings you are not blindly trying to extract information from random data. You already have a VALID LOCAL temperature record to compare against. Any thing that does not match this is not valid data!"

Tom P, or you, have been told both on CA and on WUWT why this is a bad idea. Why do you continue to ignore the explanation that has been given to you?

"Tom P: on WUWT has repeated McIntyres R code but included the trees under scrutiny. The plot he obtains is very hockeystick-like. Aparently the excluded trees have more recent data and stand alone in that area."

"A simple look at your results, along with a look at the two data sources you are merging should have told you that your results were wrong. First of all, Steve had already done the merge and he included it in his post. Second of all, you had 100% Yamal data at the end of your chart."

"Is it wrong to still exclude them? Or are they a valid set of data which should be included?"

No, it's not wrong to include the Yamal samples, as long as you include the rest of the Yamal samples. Regardless, the hockey stick disappears.

Sep 30, 2009 at 4:35 PM | Unregistered CommenterTilo

This seems a major academic scandal. I am trying to start an e-petition to Number 10 for a Public Enquiry into academic integrity at the CRU. It will, presumably, be available for signing in the next day or so (provided they accept it). Please feel free to sign it.

Sep 30, 2009 at 4:48 PM | Unregistered CommenterMichael Taylor

Tour de Force, brilliant.

Sep 30, 2009 at 4:57 PM | Unregistered CommenterDennisA

September 30, 2009 | Tilo you are looking at this proble through the blinkered eyes of a statistician (yours or McIntyres).

In most real world measurements -i.e. ones that show noise on the signal- it is quite acceptable to look at the data (plot if necessary) and any points/plots that are in gross disagreements with the other data are removed (having fully investigated possible causes of error). They are in error -i.e. not valid. Why include invalid results if they are known?

If I am measuring the signal to noise ratio of a receiver in a noisy environment (the cleaner is vacuuming the office, lights are switched on/off etc) I will get results that are not justifiable. I would make many measurements and those that have noise bursts i would discard (having ascertained that the noise was not being generated by the unit under test).

Is this wrong?

Sep 30, 2009 at 5:12 PM | Unregistered Commenterthefordprefect

Well thank goodness this gang of scientists are in the Climate Field and not developing new medicines. Their "selective" use of test data would mean a lot of dead people.

In their case, the up till now invisible research methodologies have only resulted in tens of billions of dollars or research money being diverted from other science and focused on the problem of global warming.

Their now very suspect research procedures have also been the major scientific plank supporting a massively expensive and economically intrusive public policy that targets and punishes CO2 as the cause of what they say is very bad climate change.

A lot depends on the their ability to come clean after years of dodging and obfuscation.

A lot.

Sep 30, 2009 at 5:21 PM | Unregistered CommenterFred

I have selected a few parts of this article (along with some text from RealClimate.Org to fill in gaps) and reassembled them into a ringing affirmation of Prof. Briffa's work. Most of the words were in the article so my assembly must be valid.

You don't don't seem to get the beauty of methodologies that free us from the tyranny of empiricism. The hockey stick genre is the first truly PoMo field of science but you seem to want to return to the dark ages of evidence, logic and integrity. Fascist.

Sep 30, 2009 at 5:21 PM | Unregistered CommenterGeorge Tobin

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