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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)

Lorax, I am looking at Salekhard station, listed as Salehard in Gistemp.
Some studies do in fact compare proxy values to global or hemispheric temperatures, but I consider that to be a flawed method, and in general they look at area temperatuers when comparing.

For Salehard station, there is warming from 1960, but the same warming temperatures existed from 1925-1950 as well. Temperatures from 1985 are roughly flat, and this was presented in an AGU paper as well, see

I just graphed a 5 year average of annual mean anomaly.The graphs of Yamal proxy that I see do not match this behavior, except for having a downturn in the 1960s.

Oct 1, 2009 at 7:54 PM | Unregistered CommenterMikeN

The summer anomaly for Salehard does not exhibit the same behaviour as the winter, and most of the warming signal for recent times comes during the winter, while the tree's growth shows a response to summer temperatures, if I understand their paper correctly.

Oct 1, 2009 at 8:09 PM | Unregistered CommenterMikeN

Michael, do you honestly not see how McIntyre is manipulating things here? As for you claim that "No rational, honest mind that reads what Steve posts at Climate Audit would conclude that Steve claims to have "refuted AGW". Really? Now go to WUWT and CA and see what followers of McIntyre there are posting about the implications of this for the HS. They can hardly contain their glee that the HS has now "been broken for a second time". The very obvious insinuation is that the AGW "paradigm" is based on a pack of lies. Also read Dave Delingpole's recent diatribe in the Telegraph.
This not a "straw man" argument, I made it very clear from the outset that McIntyre's "results" are being abused by those in denial of AGW to further their agendas, yet McIntyre is not being honest and open as to the true implications of his results and what they mean in terms of the HS and AGW. If he does not have an agenda, then he would have certainly immediately set the record straight on his blog and elsewhere where he has been cited. But he has not and very likely will not, and that is unethical and irresponsible of him. History is going to paint a very unfavourable picture of McIntyre and his ilk unless they stop catering to those in denial under the guise of 'accountability" and "ethics" and "science".

Oct 1, 2009 at 8:44 PM | Unregistered CommenterLorax

The hockey stick is not the same as AGW.
The only reason various blogs see this as the death of AGW theory is because it is the scientists who have allowed the shoddy work of Michael Mann to infect their work. They put the hockey stuck in the Third Assessmen report 6 times, and they issue press releases about unprecedented temperatures caused by climate change.
If they wouldn't latch on to the hockey sticks as proof of their claims, McIntyre's work breaking hockey sticks would have no effect on AGW.
The first IPCC report showed medieval times as warmer than now. They did not see this as contradicting AGW.

Oct 1, 2009 at 8:51 PM | Unregistered CommenterMikeN

MikeN: "If they wouldn't latch on to the hockey sticks as proof of their claims, McIntyre's work breaking hockey sticks would have no effect on AGW."

Mike N, proof of what claims? Who are "they"? These are some pretty broad statements that you are making. How has Mann's work "infected" scientists work on AGW? We know from studies independent from those of Mann (for whom you seem to hold much contempt) that the 20th and 21st century warming (and GHG concentrations) is highly spurious/anomalous. One does not have to rely on Mann's or Briffa's data for that.

This fiasco certainly shows that proxy analyses have problems (especially tree rings which respond primarily to warm season temps, when most of the warming has occurred in winter (consistent with the AGW theory)). But is has no place in the AGW "debate". The instrumented record does not rely on proxies, the model simulations do not rely on proxies, measurements of glacier retreat do not rely on proxies et cetera, et cetera.

McIntyre still needs to clarify the situation rather than delighting in continuing to "muddy the waters". It would also help science and everyone else if he actually made a temp. reconstruction and submitted his findings to a reputable journal. That way everyone has access to it, and not only those who are familiar with his blog. Otherwise, his findings should be submitted to a journal which deals with paleoclimate, or a journal which deals with statistical methods.

Oct 1, 2009 at 9:10 PM | Unregistered CommenterLorax

Lorax wrote:

Michael, do you honestly not see how McIntyre is manipulating things here? As for you claim that "No rational, honest mind that reads what Steve posts at Climate Audit would conclude that Steve claims to have "refuted AGW". Really? Now go to WUWT and CA and see what followers of McIntyre there are posting about the implications of this for the HS.

Steve has three core positions that he reiterates frequently:

1) That humans have likely contributed to some amount of warming, though how much is still uncertain, and:

2) That demonstrating that one hockey stick or 2 or even 10 is not statistically robust in no way, shape, form or fashion refutes AGW, and:

3) That specualtion about the motives of any AGW researcher whose work he audits are inappropriate and against his blog policy. He snips lots of comments for violating this one.

Those are his official positions -- and he routinely reminds his commenters of all three. So he does indeed "set the record straight" all the time. Probably the single most-used sentence you'll read from Steve to his commenters is, "You are going a bridge too far if you think this refutes AGW. It doesn't."

Thus, I fail to see how you can accuse him of not being "honest and open about the true implications of his resuts and what they mean".

As far as what his followers may say -- or what others may say at other blogs -- other than what he is already doing by constantly pointing out the three points above, what else do you expect him to do?

Oct 1, 2009 at 9:39 PM | Unregistered CommenterMichael Smith

Lorax wrote:

This fiasco certainly shows that proxy analyses have problems (especially tree rings which respond primarily to warm season temps, when most of the warming has occurred in winter (consistent with the AGW theory)). But is has no place in the AGW "debate". The instrumented record does not rely on proxies, the model simulations do not rely on proxies, measurements of glacier retreat do not rely on proxies et cetera, et cetera.

To the contrary, the proxy analysis is central to the debate. The climate modelers tell us that they cannot simulate the recent warming except by using a CO2 forcing -- that without that forcing, the models will not show any sort of warming trend.

This means the models cannot explain the Medieval Warm Period (MWP) -- it means the models are incomplete and must be missing some important climate variables. On the other hand, if there is no MWP, or if it can be shown that modern warming is significantly greater than the MWP, then there is no problem with the models.

This is why there has been a vast effort to use dedrochronology to reconstruct past temperatures -- to find out whether the current warming is "unprecedented" and thus "alarming" -- or something that can and has happened independent of man.

And by the way, if you look at all these allegedly "independent" verfications of Mann's work, you'll find the overwhelming majority of them simply use the same faulty tree ring data that Mann used. Some independence!

Oct 1, 2009 at 9:49 PM | Unregistered CommenterMichael Smith

Michael, thanks for clarifying that-- I'll look on his web page to see whether he makes a point of that in some kind of "mission statement. Did he "feed" the story to Delingpole? Even if he did not, why has he not made a point of setting the record straight? Let us not be naive Michael, there is a lot at stake here, and we all know that even the clergy do not practice what they preach. So let us not assume that McIntyre is any different/superior. I maintain that McIntyre has an agenda, why else would he focus almost exclusively on those papers which pertain to AGW in any shape or form? To me this speaks volumes! Audits should be done randomly, I agree that more journals should do audits, but what he does smacks of a witch hunt to discredit climate science, especially those climate scientists who understand AGW to be a credible threat.

Oct 1, 2009 at 9:54 PM | Unregistered CommenterLorax

As a matter of fact, if you look at Watts' Sep 30 "roadkill" blog, there is an update where McIntyre does, in fact, set the record straight

Oct 1, 2009 at 10:22 PM | Unregistered CommenterMaurizio Morabito

Maurizio, actually no McIntyre did not set the record straight! Just more obfuscation and allegations. I am busy, could you cut and paste the part where he sets the record straight? I would be very grateful, thanks.

Also, now look at the first comment posted on the WUWT site in response to today's story:

"So the entire hoax of AGW was built on a single tree ring?

And we are a Senate vote away from taxing ourselves into oblivion based on this hoax?

This really should end the practice of bending over backwards to be civil to the lying scum AGW team."


Oct 1, 2009 at 10:35 PM | Unregistered CommenterLorax

Lorax, they put Mann's hockey stick all over the IPCC report. I agree that a refutation of the hockey stick would not impact AGW theory substantially. The first IPCC report had a different reconstruction that showed a warmer medieval warm period.

Oct 1, 2009 at 11:24 PM | Unregistered CommenterMikeN

<B>Maurizio, actually no McIntyre did not set the record straight! Just more obfuscation and allegations. I am busy, could you cut and paste the part where he sets the record straight?</B>

This is so typical of what LORAX has been posting on several blogs. Jump to a conclusion, in this case that McIntyre didn't set the record straight, and then ask for a cut and paste of what LORAX already said didn't happen.

Another example of ready, shoot, aim: <B>We know from studies independent from those of Mann (for whom you seem to hold much contempt) that the 20th and 21st century warming (and GHG concentrations) is highly spurious/anomalous.</B>

Wow, may I suggest you read about these paleoclimate reconstructions before jumping in and making such claims? The claim of independent reconstructions is central to this topic with Yamal and Bristlecones being used in almost all of these. Most share coauthors and some even use Mann's PC1.

LORAX - you are passionate about this subject, but please get your facts straight and please stop attributing statements and positions to Steve McIntyre that are not true.

Oct 2, 2009 at 1:03 AM | Unregistered CommenterJimR

Outstanding writing and scholarship for us non-scientists struggling to understand the real science of climatology. Thank you.

Oct 2, 2009 at 3:22 AM | Unregistered CommenterChris G - TN USA

re: Dr. Briffa and "the Russians made me do it"

Hmmm. I can see it now, an "it'll never work, but my cousin is a dendrochronologist.." plan by two wizened apparatchiki in a basement in the Kreml. A maskirovka worthy of their best chess masters. They set a trap for the non-numerate global "progressives" to destroy their own economies and freedom of thought and we just couldn't resist it. What is it about the human condition and our need to create our own golden calves?

A tragedy of classic sense. That which we do to ourselves, wittingly. Or a movie script.

Well, I can dream.

Keep up the good work. Hopefully this will rekindle students' interest in the scientific method and encourage the young to question and challenge authority.

Oct 2, 2009 at 3:34 AM | Unregistered CommenterAri Tai

I wish, I wish oh how I wish that somebody would confirm to me that effect follows cause, and not the other way round.....I don't know if I'm coming, going, have been to, or am returning from anywhere.

Why does Co2 rise follow warming....I can't find a reasoned answer that doesn't rely on sophistry....

will some here point me the way ?

Oct 2, 2009 at 4:31 PM | Unregistered Commenterconfused

This is great work, but you guys need a legitimate, broad audience. People don't read these days, especially not Americans. Make this into a slideshow with audio explanation and post it on youtube. Make it clear and simple that HS theory is a fabrication.

Modern folks respond to the visual.

Oct 2, 2009 at 4:50 PM | Unregistered CommenterVinceS

One of the things that caught my eye in your excellent synopsis was the tidbit of how Briffa's data and paper contradicted all of the historical accounts of the MWP, claiming quite the opposite -- the coldest year. Now someone tell me this, if you are a scientist, and truly interested in getting at the truth, and not just someone seeking a headline with a sensational claim (no MWP), wouldn't the very first thing you'd do would be to try to find other data or explanations for your outlier conclusion. But not with the global warming crowd. Oh no, they celebrate these statistical outliers and then call it consensus science. Perhaps it was not Briffa's job to contradict his own study, but, my lord, shouldn't it have been torn apart by other scientists, or at least called out as an outlier instead of embraced as true evidence showing global warming? That's a rhertorical queston, in case you were wondering.

Oct 2, 2009 at 6:19 PM | Unregistered Commentermbabbitt

All of this to do about nothing. Centuries represent such slow changes in temperature as to be lost in the noise. What is important is the temperature changes over millenia. Here's a very good data point. When my ancestors crossed the Bering Strait ~ 21,000 years ago, most of this continent and South America as well was covered in ice. So, they settled along the Pacific Coast all the way down to southern tip of South America. There are thousands of native settlements along the sea coast, but they have only be recently discovered, because they are 300 feet below sea level. There is a significant exhibit at the Journey Museum in Rapid City, South Dakota that goes into significant scientific detail.

This translates to an approximate increase in sea level of around 38 cm. per century. There is no doubt that on this much more appropriate scale, that the earths temperature has been increasing, pretty steadily, for the last 210 centuries. Some up and some down, but the trend is unmistakable.

This does not answer the question as to whether the current, miniscule up-tic in global temperature (over the last 4-5 millenia) has been recently influenced by humans, but it does confirm that global warming is going on, and that, on average, we should see another 38 or so cm of increase in sea level by 2100. This does, by the way, tend to agree with the average of the climate models on the U.S. DOE global warming website, which, I believe appear, on average, to be predicting about a 36 cm increase in sea level by 2100.

In my opinion, we should be concentrating on how to mitigate what will undoubtedly be very significant and devestating effects of this, apparently, inevitable rise in sea level during the next century. For now, we have a lot of reasons in the U.S., not the least of which is the growing demand for petroleum and the fact that most of the worlds supply is controlled by unstable nations, to switch from fossil fuel generated energy to renewables.

J. Jones, Ph.D.

Oct 2, 2009 at 7:05 PM | Unregistered CommenterJ. Jones

Confused said;

"Why does Co2 rise follow warming....I can't find a reasoned answer that doesn't rely on sophistry..."

There is a great deal of co2 in the atmosphere. There is even more in the oceans. The theory is that when the world warms naturally and the sea warms, the oceans outgas co2 into the atmosphere. (Like warm coke) The additional co2 is then said to cause further warming as it is a greenhouse gas and 'traps' heat. When the world cools and the sea cools the oceans sucks in that atmospheric co2 which lowers the GHG concentrations in the atmosphere, which further helps cooling.

Theoretically man is artificially adding to the gas concentrations so more is always present in the atmophere and therefore causes more warming than would naturally occur.

The time scale that this happens over is very debatable. New Scientist once said it was 800 years-as glacier cores seem to show this delay in cause and effect. I personally think it is very much quicker. I also think the exchange between air and ocean is very much greater and more variable than is shown at the official co2 recording station at Mauna Loa. MInd you, that is another story.

Google 'the carbon cycle'; where you will find many explanations with graphics that explain the amounts of co2 involved in this exchange .


Oct 3, 2009 at 12:45 AM | Unregistered Commentertonyb

It is really cool nto ave this////
This made me tear up.......

And that is some serious paneling, my friend.thank u post.....

Oct 3, 2009 at 6:57 AM | Unregistered CommenterHockey Picks

What caused the global warming such that palm trees grew in the Arctic as well as the Antarctic? And, how about the global warming that allowed agriculture in Greenland around 1100 A.D.?

Oct 3, 2009 at 7:58 AM | Unregistered CommenterRStein

Before the great Flood the earth's axis was true north and south. There were no polar regions. The planet was lush and garden-like, with less sea water and more land.

Oct 4, 2009 at 12:30 AM | Unregistered Commenterreader

History is going to paint a very unfavourable picture of McIntyre and his ilk unless they stop catering to those in denial under the guise of 'accountability" and "ethics" and "science". LORAX

Now 'That' is religious fervor.

Lorax, do you believe the earth is millions and millions of years old?

I thought so.

Good thing it survived all those millions of millenia without a climate catastrophe. Phew!

Oct 4, 2009 at 12:49 AM | Unregistered Commenterreader

You complain that McIntyre only audits AGW papers. Do you also complain that Mann, say, only writes AGW papers?

Oct 4, 2009 at 2:10 PM | Unregistered CommenterRene

RealClimate has come up with two responses that may have merit:

* Briffa may have had good reasons for picking the few trees he did - ie, that they were those whose rings best showed a temperature record (and not other factors such as water).
It's more than a little odd he has never explained this though, it must be said. Almost as odd as hiding the raw data.

* There are apparently Hockey Sticks in data from boreholes and all sorts of other non-treering data.

Perhaps the Bishop would care to evaluate for us?

Oct 4, 2009 at 2:27 PM | Unregistered CommenterRene

Robert E. Phelan saith: "yeah, it would help if colonials could spell." September 30, 2009

That will happen when the New York Times publishes headlines like: "Cracks in Global Warming" or "Briffa Turns in the Wind." We're a hopelessly illiterate lot, Robert. You guys keep using long words instead of short ones like "tree ring dating." But I guess sesquipedalian phraseology is to be expected in fields of science such as "dendrochronology." "dildoclimatology," and paleoecology."

Oct 4, 2009 at 5:24 PM | Unregistered Commenterjorgekafkazar

Rene, the other hockey sticks are mostly irrelevant. If you only go back to 1400 or 1600, then you are not proving anything. The whole point is that the Medieval warm period around the year 1000 was warmer.

Other charts that they show have problems with including bristlecone pines, and bad methodology. Everyone of those has been challenged at ClimateAudit, and in my opinion, convincingly so.
The charts are from Mann08, Kaufmann09, and Osborn and Briifa 06.

Selecting cores that match a temperature record has a problem because you don't have a past temperature record to match against. So if you match 20 good trees now, vs in the past 20 good trees and 20 bad trees, hos wan you compare the average of 20 good vs the average of 20 good and 20 bad?

In addition to that, the number of 'good trees' is too small to get a good reconstruction.
You should also ask these questions at RealClimate and see what they have to say.

Oct 4, 2009 at 9:17 PM | Unregistered CommenterMikeN

As a true laymen, I hadn't even heard of any of this before reading this article. My first impression was that this should be a really huge story, but my attempts to verify came up empty. Everything I found online linked back to this website. Could someone point me in the direction of a verfiying source on this subject? My ignorance on the esoterics of climate change science is leading me to believe this is all made up, even though I personally would be inclined to believe it since I've been a sceptic for years.

Oct 5, 2009 at 3:40 PM | Unregistered CommenterZach


Oct 6, 2009 at 3:55 AM | Unregistered CommenterMikeN

Surely the main point about the Medieval Warm Period is that, although most evidence suggests that temperatures then were probably in the same ball-park as now, there are too little reliable data to show with acceptable levels of mathematical probability whether or not it was warmer than at present. As far as Greenland goes, we know that the Vikings colonised the extreme south west (warmest) tip of Greenland for a relatively short period in medieval times, and left when temperatures cooled. This area is pretty much on the same latitude as areas they came from in Scandinavia. Recent recession of ice in Greenland has uncovered settlements that existed then, suggesting that temperatures now could be as high or higher now than the peak MWP.

This all seems a bit of a storm in a teacup, except for the suggestion that Briffa and co may have falsified results. It seems to me that we don't know yet whether they set out to deceive or whether they excluded much of the data for legitimate reasons - e.g. that the data were judged to be anomolous , as someone has earlier suggested. I think we should await a full explanation from them, and that we should maintain as much objectivity as possible. Expressions like "AGW alarmists" don't inspire confidence in the objectivity of the poster, nor do similarly partisan-sounding expressions from the other side - though I have to say, I hope objectively, that most of the disdainful and dismissive comment seems to come from the direction of the "skeptics".

Oct 7, 2009 at 12:44 PM | Unregistered CommenterFRWilliams

FR Williams

You really need to read up on your Viking history. A good place to start is with
'The Viking World' by Stefan Brink who records over 500 farmsteads.

There are still remains of Viking dead buried in the perrmafrost-It wasn't perma frost when they were buried :) The Vikings inhabited the srea for some 400 years-that is hardly a short time and had their own Bishop who visited them from Iceland. The colonies died out when the sea lanes iced up again

I agree with you re waiting for the data to be explained by Briffa-although he doesnt help his case by his previous long silence on the subject.


Oct 9, 2009 at 12:04 AM | Unregistered Commentertonyb

I hesitate slightly to post here as I am in no way scientifically qualified to comment on much of the research at the level of climate chemistry or physics. However I can read statistics and even at that fairly rudimentary level I have been highly unconvinced by the hockey stick graph for some time. Rather more importantly, as an historian, I know that there is a great deal of historical eveidence which would suggest that the MWP is no figment of anyone's imagination and that there have been short-medium term changes in climate during the last 2,000 years or so of recorded history.
We do not know the exact root causes which kicked off the various movements of nomadic horse peoples from Western and Central Asia, in the past, although climate change may be a major factor. We do know that there were changes in weather patterns during the Medieval period from a whole raft of historical information. Changes in farming practices particularly involving the advance and retreat of viniculture and wheat growing norhwards and eastwards. Migration patterns of German peasntry; first moving north and east, into the Baltic area than withdrawing westwards and southwards during the late Medieval period. Growth and decline of population, famine records and changes in the pattern and intensity of various diseases all point to rapid warming and cooling trends in temperature.
These climate variations did not halt at the end of the Medieval period but they appear to have gone on taking place much nearer to home in historical terms. We have the example of the mini ice age (so called) from the lte 16th throughout most of the 17th centuiry.Henry Kamen amongst other specialist historians of the period has remarked on this. We have the regular freezing of rivers such as the Thames, with it's 'Frost Fairs' right up until the early 19th century. There is even some evidence from the report made to Congress of the Lewis and Clark expedition which doubted the viability of farming in most of the Mid West/Great Plains area due to the aridity of the climate. About 50-60 years later the area was one of the world's major grain growing regions.
In the face of a mass of historical evidence of the kind outlined above then the science for downplaying or denying the MWP better be spot on. I don't think it is.

Oct 9, 2009 at 12:30 PM | Unregistered CommenterJohn Munro

John Munro

You might like to go to my guest posting here which deals exactly with your topic.

I also made a comment that provided further information


Oct 13, 2009 at 12:35 AM | Unregistered Commentertonyb

V interesting. I refer all readers to Stephen J Goulds book, the Mismeasure of Man. Apparently, 100 years ago eminent scientists were busy trying to prove that white men were more intelligent than black men by filling the empty skulls of two samples with beans, then counting the beans to prove the brains were bigger in white people, The propensity to bias in favor of prejudice was as as prevalent then as it is now.

Oct 16, 2009 at 11:06 AM | Unregistered CommenterGareth Young

I am a little late to this party, so please forgive me while I get to grips with this. It's beginning to sound like the Hormone Replacement Therapy fiasco of recent years.

I understand the importance of the Yamal tree series in proving the Medieval Warm Period didn't happen, but the denial of that period is only important if one is trying to prove that the current 'up tick' in temperatures is extraordinary in recent geological time.

The 'momentous' data is the up curve of the graph over recent years.
But why is there an emphasis on just this one set of tree data? Surely if there is global warming (anthropogenic or not) then 'all' trees will show similar growth patterns. There is no need to only look at very long lived trees (bristle-cones, etc) you should be able to use any mature hardwood.

It ought to be trivial to obtain thousands of data sets, from locations all over the world, running back over the last few hundred years - the unremarkable tree outside my window is over two hundred years old. You don't have to travel very far - most university campuses are stuffed with ancient oaks.

This is simple science. Has that been done? What were the results?

Oct 24, 2009 at 2:45 PM | Unregistered CommenterDavid R


You're not quite right. Only trees that are limited by temperature should show growth spurts in recent decades - those on upper treelines on mountainsides and those at the northern limits of their geographic range (or southern limit in the southern hemisphere). Growth rates in other trees may be limited by other factors such as precipitation.

Oct 24, 2009 at 4:06 PM | Registered CommenterBishop Hill

Ah - OK, I understand your point.
But may I take another shy at this coconut?

The growth record at the extreme of the habitat is a proxy for temperature increase - which is itself of interest as it is a proxy for climate change overall. After all, temperature rise in and of itself wouldn't matter if didn't indicate that the global climate was changing.

If global /climate/ is changing then that change should be observable everywhere on the planet, but not necessarily as a rise in temperature at every location. There could be all sorts of local effects, as you say.

However, taken overall there should be measurable /change/ in the growth of any individual tree when taken in comparison with the previous average growth of that same tree. So plot the year by year change in growth over the last fifty years in comparison to the average year by year growth of the preceding 200 years. It is not important whether it grows more or less. One is simply capturing a measurement of the change in growth conditions. This measurement would need to be taken from many trees, using a random sampling of locations.

Then surely one should see an increasing divergence matching the Yamal recent up-tick. Or not.

There are a couple of further points. The trees selected for sampling should be of species that at around 250 years old is still in vigorous growth; an oak, say. It doesn't have to be the same species all over the world, though, as one is comparing growth-change on a tree by tree basis. This sidesteps the whole RCS issue.

I am not proposing this as a method of measuring /temperature/ change, but as a method for demonstrating whether there is a measurable climate change in the last fifty years. Or not.

Oct 26, 2009 at 3:35 PM | Unregistered CommenterDavid R

It is not clear to me that either you or McIntyre understand the basics of dendroclimatology. The location (elevation, latitude, etc... ) and age of the tree would be all important. A particular series has to be compiled from measurements on many trees. One "core" is not going to show climate with equal sensitivity throughout the tree's life. Briffa and other researchers have decline to involve themselves with McIntyre because he has a clear agenda in terms of pattern.

Nov 22, 2009 at 1:01 PM | Unregistered CommenterDon Thieme

I visit Climate Audit occasionally and always leave wishing there was a "Climate Audit for Dummies" somewhere on the web. Thanks for taking the time to give a great summation for us dummies.

Nov 22, 2009 at 3:23 PM | Unregistered Commenterdan

1) "It is not clear to me that either you or McIntyre understand the basics of dendroclimatology. The location (elevation, latitude, etc... ) and age of the tree would be all important." Such methodology seems flawed to me. Much easier method for analyzing such type of data is by using factor analysis on whole set of observations. Temperature should be major (most likely first) factor. And you get many additional informations as a bonus.
2) "Briffa and other researchers have decline to involve themselves with McIntyre because he has a clear agenda in terms of pattern." Very poor argument indeed. Does not have Briffa and others their own clear agenda?

Nov 23, 2009 at 5:40 PM | Unregistered CommenterL8M

Thanks for the info, and your superb presentation in the King's English.

Many years ago I had read of a paper (maybe in Science?) that re-analyzed data published long ago that purported to show Africans and other sub-creatures had smaller brains. The authors made the mistake of publishing their original data. Upon re-analysis there was no correlation of brain with race. (However one defines race.)

I always had a gut feel that the tree ring data was complete b*********, but never knew the original data was never made available for review. With everything riding on these temp reconstructions, it is astonishing folks essentially took the word of one person.

Anyway, thank you!

Nov 25, 2009 at 3:00 AM | Unregistered Commenteroracle2world

the questions i've never heard asked are:

if satellites can determine the earth's temperatures, can we determine the temperatures of other celestial beings within our planetary system? can we look at the temperature variations of said planets - and compare them to our planet?

if solar energy is the main culprit in our ecosystem, shouldn't the same effects be seen on other planets/ moons?

if a correlation can be drawn, doesn't AWG become debunked?

we need to think simply. the truth is usually the simplest explanation.

Dec 2, 2009 at 5:57 PM | Unregistered CommenterMichael

Thanks for the 'layman', from one! Here in the UK we can't have a decent weather forecast for the next 5 days using some of the worlds fastest computers and complex data analysis. Little wonder the majority of people here don't believe the 'its all man made' scenarios conjured up by the scientists. The greatest problem of course, up to now, is the fact that the whole issue of climatology is 'clouded' .... ahem ... sorry ..... by funding for research. i.e you only get it if you are researching 'global warming'!!!

Dec 3, 2009 at 3:28 PM | Unregistered CommenterRussell

Climate change and the Roadrunner

I am a mathematical physicist and I write to congratulate you and certainly Steve McIntyre for your work. That's what's needed now: a careful study of data and a good story which shows that myth debunkers are real science heroes, not those who fudge and hide their data and - I start to be concerned about this - give science a bad name in the public eye. And don't worry, your story will be picked by the mass media and will help set the record straight for thousands of people.

At the urge of I read the scientific papers on corrections to raw temperature data, and realized where the major flaw lies (maybe you could write a story about that?). If the CRU does not make available the raw data and the reason and magnitude of each correction for every weather station - which if they had nothing to hide they could easily instruct their program to do - until then, they can adjust the magnitude of the corrections simply by changing a parameter of their software, and no one would be able to check it. That is another reason for which they cherrypicked Russian stations with a broken record over the stations with full data, since the former leave room for many more corrections.

There is an avalanche of documented stories just in the last few days about the fudging of the Russian and New Zealand data by the CRU, the US law order preventing CRU from further tampering with their documents, etc.

I have now in another window news from the Copenhagen summit, the whole made up climate scare, with
heads of state inside committing huge resources and with genuinely frightened people outside, none of whom has thought about:

-opening a browser and looking for "raw temperature data, raw ice extent data, raw tree rings data"
-spending one hour looking at that data, and
-making up their own minds.

However, the whole climate scare scene looks now like the Roadrunner from the classic cartoons:
his feet are running at full speed, but he is up in the air above the Grand Canyon, about to start to fall when he starts to realize what's really going on ...

Thank you agin, and keep up the good - and important - work

Dec 18, 2009 at 8:11 AM | Unregistered CommenterAdrian O

Very helpful summary.

Dec 23, 2009 at 3:24 PM | Unregistered CommenterKevin

Lorax asks: "I maintain that McIntyre has an agenda, why else would he focus almost exclusively on those papers which pertain to AGW in any shape or form?" -- probably because no scientist was asking those questions. McIntyre saw a graph and asked for the underlying data. He was told by Mann that it didn't exist. McIntyre discovered that no one else was trying to reproduce the poster child of global warming. His dealings with the dendro-scientists over the next several years probably hardened his resolve. My question is why aren't other scientists doing their job? Why aren't they trying to reproduce the foundations of their science? Was Feynman correct in his Cargo Cult speech. Is it just too darn expensive and not worth the effort to reproduce the science you're building your house of cards upon?

Apr 10, 2011 at 11:12 PM | Unregistered Commenterel

Now, years later, it emerges that Steve McIntyre was right all along and also that "it's even worse than we thought" -- updates for anyone still finding this vital legacy thread:

Finally, Yamal FOI response shows what CRU was really about

Bish, maybe it's time for a new or expanded "Yamal Implosion" post??

May 7, 2012 at 9:39 AM | Registered CommenterSkiphil

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