Bishop Hill The Yamal implosion
Sep 29, 2009 Climate 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]
Reader Comments (147)
Thefordperfect,
Yes you obtuse fool...it is wrong WHEN you only do that to a small PORTION of your data and not the entire data. Since Rriffa couldn't possibly do that to older samples (there is no thermometer record 500 years ago) adding cherry picked data to the END of your graph produces a hockey stick.
If all the data of his study is averaged out ...good treemometer trees with bad ones except the very end where only good treemometer trees are used..you get a hockey stick...Why? Because those "bad" treemometer trees pull down the average (or pull it up in cold times)...then tend to flatten out the curve.
If you flatten out the curve right up to modern times...then use a different method for those times....you get a hockey stick graph. It's gibberish, rubbish...you aren't then comparing tree rings from today to 500-1000 years ago if the methods aren't the same.
This is like explaining the word "the" to a toddler. You can't really be this daft can you?
"The bristlecone pines that created the shape of the Hockey Stick graph..."
Those are some talented trees.
Excellent article. Thank you for taking the time to summarize this in terms that someone like me can understand.
Thank you for the excellent narrative of the events and time line. One of my self-assigned tasks is, as a layman, attempting to explain to the general public both the science and issues related to climate change issues. With your piece you have generated material that any reader could comprehend. My congratulations.
Sincere Regards,
Lee Kington
Meanwhile, the press ignores this major revelation and, as we speak, Barbara Boxer and John Kerry rush to force thru a "climate change" bill incorporating a cap and trade scheme based on a completely fabricated environmental emergency. Honestly, the whole thing sometimes just feels surreal.
thefordprefect:
"Is this wrong?"
Yes, it's wrong. I'm not going to start from scatch each time that you post the same question someplace new. Now go back to CA and WUWT where I explained to you why it was wrong and read it there. Then we can continue from that point.
Maybe there should be some links to the relevant articles at http://www.climateaudit.org/ and http://wattsupwiththat.com/
Thanks Bishop for a very digestible article - which is extremely well-written. Sad to say the obvious of course, but this quality of reporting and whistle-blowing would have been common-place in our mainstream media only a few years ago. The fact that it no longer is (indeed, the Guardian is actively censoring any public mention of this story), is depressing. But perhaps what we are witnessing is the slow and painful death-throes of the dead-tree press (no pun intended), to be replaced by a far more alert, honest and responsive reporting on the web - of which your writing here is a prime (and hopefully, historic) example.
Bishop Hill,
Thank you for such a clear resume of the developments - I had not appreciated a number of points that you so eloquently pointed out.
I hope that finally people may view Steve McIntyre's work with the respect it deserves. Equally your contribution in "telling the story" should be recognised as well.
H&S used a substantially different method from Briffa, and if I understand McIntyre correctly, the H&S finished product is not very good at discerning temperature trend on a large time scale.
Now what will you do about all the other hockey sticks? =)
Royal Society B,
Talk about shooting yourself in the foot, I bet a pound to a penny you won`t get a team member submitting a study to that journal in future.
What a pleasure it is to read a totally clear exposition of what so-called scientist prefer to keep in their own language - which only their brothers in "the priesthood" speak. There is no greater crime in a profession who's raison d'etre is to discover "the truth" is to be caught with your pants down, "lying". Its like priests who turn out to be just kiddy-fiddlers, or fund managers running a Ponzi-shceme. Its a fundemental betrayal of trust.
Our many academics and "Vichy scientists" fear for their careers if they deny warming, so they keep quiet.. Journalists are no better in this, looking no further than the next next caption pun on "green" or faux-pollution photo 's. There are the disgusting British Antarctica Survey grant-hounds - "its all worse than we thought. its happening before our eyes, the ice is starting to break up, were all going to die" (please fund next year's research)
Well we don't trust you any longer. Not any of you. You don't deserve it.
Lies do not last forever. There is no such a thing as the "perfect crime". Suspects always left a trace behind (a "carbon footprint").
The dedicated forensic science effort by McIntyre has done a whole lot more than bury the hockey stick. Exposing the corruption within "settled science" has a far greater impact for me. Well done Steve McIntyre and well done Bishop for your excellent summary of a story that's been unfolding for a while. I've been having trouble persuading people to wade through the complexities but now I can just send your layman's guide. Thank you from Australia
Re: 40 shades of green.
What a great typo. I want to get pubslished now even though I am not and never have wanted to be an author.
It's odd - now that I look closer, the new reconstruction with the Schweinberger variation does not seem to agree with the measured record for the twentieth century. It still has a definite hockey stick blade.
For that matter, apparently ocean temperatures do too.
What now?
This is a disaster for the AGW supporters. If the hockey stick is dead and the new graph shows the Medieval Warm Period as being significantly warmer than it is now, that tipping point they keep telling us about must be a lot further in the future than Prince Charles 48 months.
It also shows us that AGW scientists are willing to commit academic fraud (don't forget there were additional studies that supported Mann's original study) for some at the moment unknown reason. What can we now trust? Why didn't the peer review reveal this.
Add to this the lack of warming right now, the lack of a "hotspot" and the utter failure of the climate models to predict any of this, and you have a theory that is in serious trouble.
Very clear exposition of the discrepancies in the tree ring data etc.. Thanks. One thing puzzles me, I have seen NASA global Land-ocean temperatures for 1901-2008 which appear to show a clear overall warming trend. I appreciate points being made about the original hockey-stick graph smoothing down the Medieval Warm period etc, but don't the actual measurements available for the 20th century confirm the upturn? Or am I missing something?
Just to say - excellent, lucid presentation, Bishop. If this (and your earlier Hockey Stick post, plus the next few instalments in this saga, which I'm sure will come along in time!) were expanded into a book, I think you'd have a best seller on your hands.
Also, can someone explain how all this affects the validity of the 2006 Nataional Academy of Sciences report Surface Temperature Reconstructions For The Last 2000 Years, which showed essentially the same hockey-stick shape as Mann et al, whilst stating that much less confidence could be placed in the results for the period 900 to 1600 AD (i.e. including the Medieval warm period) than claimed by Mann et al., although high levels of confidence were attributable to the period encompassing the Little Ice Age to the present. Am I right in saying that the recent revelations throw more doubt on the Medieval Warm period - i.e. whether temperatures then were higher than recently - and apparently also on the integrity of some of the climate scientists, but the essential shape of the hockey stick (with the upstick blade) is still valid (accepting all points about the Medieval Period and its significance)?
Almost daily the credibility of the scientific community is being trashed by those prepared to manipulate data to ‘prove’ their predetermined outcome to support the AGW/Climate Change agenda of alarmism – in addition those scientists not prepared to speak out against the totally unproven hypothesis should be ashamed.
The problem now of course is that governments seeking a new source of taxation and the financial industry seeking fee income/profits have got a headlock on the concept and seems to be convincing a large part of the western world population that Co2 is a noxious gas and that an ETS will magically moderate future climate change and ‘save the world’. This is the greatest confidence scam of all time and is an absolute disgrace - but what is more disgraceful is how the mainstream media are unquestioningly aiding and abetting the AGW industry in the fraud.
It is a very dark time for the world when so much attention and money can be wasted on such a specious proposition instead of concentrating on addressing REAL pollution, REAL resource management (energy, water, land) and adaptation to the effects of unstoppable REAL natural climate change that man can neither materially affect or indeed ‘fix’.
"Also removed the reference to KB's illness which is apparently genuine"
Vindictive arsehole.
austinpowers,
Unless you are giving The Great Pumpkin a hard time for making Briffa sick, let me tell you it is poor taste to insult someone while hiding behind a pseudonym.
I'm sure we all wish for Briffa to return to health as soon as possible.
StuartR: September 30, 2009 |
theFordPrefect, I don't know if you know, but Jeff ID has looked at Tom P's work here:
http://noconsensus.wordpress.com/2009/09/29/audit-of-an-audit-of-an-auditor/
Believe me, Stuart, theFordPrefect is no one's dummy and knows, probably before anyone else, what Jeff Id has published. Ford's concern is to get in the word before anyone else has a chance to evaluate the issue. If TomP seems credible, why bother reading what some guy who calls himself "Id" thinks? Even if Id is one of the most thorough engineer-statisticians any of us are likely to meet. Visit the Air Vent at http://noconsensus.wordpress.com/ and judge for yourself.
Keep up this quality of work, yer Grace, and your next blog might well be titled Arch-Bishop Summit.... but you'll always be known to your detractors, like those in the education establishment, as Parson Gully...
I have no desire to stop people reading any informed and researched comments.
I only want the truth.
I dislike the blinkered gloating and denigration of others research. I can imagine the un-read masses scanning McIntryre jumping up and down with drool dripping on the carpet shouting "we've got them now". :o)
Hockey sticks are unimportant unless you play hockey. The real data still shows an increasing temperature which has a good chance of being due to human activities. Ignoring the change could lead to disaster. Fixing the change will cost money.
From my post on wuwt
Here’s another interesting dissertation with descriptions of the Yamal trees and environment:
http://vak.ed.gov.ru/common/img/uploaded/files/vak/announcements/biolog/2009/13-07/KHantemirovRM.pdf
Good descriptions of the environment and the trees sampled.
Unfortunately (???) he ends up with yet another hockey stick:
See figure 18
Figure 18- of change in the mean temperature of summer (deviations from the average), smoothed by 50-year filter, and the dynamics of polar timber line
Mike
Fordprefect.
Is there an English version?
Austin Powers
Not, not vindictive. I reproduced comment #7 from McIntyre's thread, assuming this implied KB was hiding. It was pointed out that this wasn't the case, so I fixed it accordingly.
FR Williams
Almost every temperature reconstruction contains either the bristlecones, which the NAS confirmed were not responding to temperature, or Yamal which we now now is not a representative of its area. We therefore have to tear up all these reconstructions and see what we are left with.
Instrumental temperatures were going up until the end of the twentieth century but have been flat since. The question that the tree ring studies are trying to answer is whether it was warmer still in the past. We don't really know.
Rob, the Royal Society has been around since before Isaac Newton. I think they'll manage without the Hockey Team.
This is all a storm in a tea cup, and those in denial of AGW should be cautioned about misinterpreting McINtyre's the findings (since when did his analyses become "truth"?). Quite simply, McIntyre's findings do not refute the theory of AGW. The CRU and McIntyre's reconstruction using the "correct data" differ in the 20th century, not during the medieval warm period. McIntyre's crusade was based on the fact that the Medieval period was much warmer than shown by the CRU data. Well, his own data show that his hypothesis was incorrect. Had McIntyre's medieval temps been as warm as SATs are now, or warmer, then I can understand the hoopla about this questioning the 20th century warming. What is does show us is that proxy data are complex, imperfect (understatement!), subject to many errors and, alas, manipulation (but then so are all data). While the observed SAT record since circa 1880 has its fair share of problems the global warming has been corroborated by numerous independent metrics other than temperature.
Now, I do not condone cherry picking and data manipulation. This story is about why Briffa seemingly manipulated the data, and has nothing to do with AGW per se. I find it ludicrous that the skeptics and those in denial are extrapolating McIntyre's findings to apply to all climatologists and to come to the bizarre conclusion that AGW is a hoax, based on problems with data from some very specific locations (i.e., data are not representative of global SATs).
McIntyre loves to not pick and critique other's work, not for the honour or integrity of science as he has convinced his devout following, but b/c he has an agenda and wishes to undermine the credibility of anyone who understands AGW to be a credible threat. Not to mention that these findings are framed in such as way as to greatly confuse an already confused public, thereby making inaction on the AGW file all the more likely. McIntyre did the same to Steig et al's paper, they made some mistakes (honest ones) , but it did not change the validity of their results. Instead McIntyre et al. painted them to be incompetent and guilty of manipulating the data. The important thing to remember is that when Steig et al. published a correction (with input from McIntyre's clan), their initial claims were still valid!
McIntyre were all in a huff about the shaft of the hockey stick, but their analysis shows there not to be issues with proxy data used to construct the shaft, but the "blade" (i.e., 20th century temps). Well, we know what the blade looks like and it shows dramatic (global) warming.
The silence from Mann et al. is probably to "let them get all steamed up and dig their hole deeper", and then we'll say something intelligent. But really, what does one say to someone like McIntyre, he does after all believe himself to be omniscient.
Lorax
You are misrepresenting McIntyre's views. He has said repeatedly that he is not trying to create an alternative reconstruction of temperatures. He is merely demonstrating that the reconstructions that are put forward as definitive by the IPCC are not robust.
Lorax, the MWP is warmer in Steve's chart.
October 1, 2009 | Lorax
I agree with your statements. The method of confusion is obvious - check how many threads are created on CA and WUWT. Respond to 1 and there are another 5 generated which also require the same response.
Unfortunately they are winning the press war at present.
Bishop Hill
As far as I know there is no english translation of the document. If you can find it on google open a pdf copy for the figures and also open the same document as html , then use google toolbar to translate.
One of the former findings against the hockey stick graph was that any data plugged into the mathematical method used for the creation of the hockey stick - always produces a hockey stick. So now we have data that shows the hockey stick isnt always generated - how does this tie in with the above - I thought any old data would produce the desired AGW curve ? Sorry to appear ignorant if I'm missing the obvious . Can anyone educate me on this please .
Roly
The Hockey Stick was a multiproxy reconstruction, taking several hundred proxy series and using them to reconstruct global or northern hemisphere temps. The process of summarising multiple series that Mann had used was found to generate hockey sticks from red noise.
Yamal is a single proxy series, but an important one that is used in most of the multiproxy reconstructions. McIntyre has been looking at how this series was created from the individual tree cores. Briffa's selection of cores from the area work came up with a hockey stick. McIntyre shows that if you use different trees from the same area you don't.
A single proxy can be important in a multiproxy reconstruction because most are based on rather small databases - between ten and twenty series in some/many of them.
There should be evidence of 20th century warming if these proxies are useful temperature proxies. This has never been in doubt. However, there is a real debate in Dendro-circles about the divergence problem where tree growth and C20th temperature increases diverge from each other. So its rare to find a population which corresponds to temperature in the way that the Yamal series did for Briffa.
However, this to be put in context with what is being discussed at CA and elsewhere. As Tom P helpfully stated on a CA thread, the Yamal series has 600+ samples so the key question is why Briffa only using 12 of those to show late C20th temperatures?
Bishop Hill,
I thought I was following Steve's work, your summary confirmed that I was. Unlike many others, I am somewhat underwhelmed by this news about the Yamal reconstruction. I guess I had already come to the conclusion that temperature reconstructions based upon treeringology was prone to subjective interpretation and therefore not of much value beyond a propaganda tool and had therefore moved on as it were.
This new finding does not falsify the AGW hypothesis. However it goes a long way to removing a distraction from the real issues pertaining to recent, current and future climate. Perhaps it may also warn other researchers off filtering their results to reflect an ideology. And maybe, just maybe it will further the desire for better peer review and data management processes.
Hi,
Searching the web I found this data set
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/asia/russia/yamal_2002.txt
from Rashit M. Hantemirov and Stepan G. Shiyatov
My question is how this data set fits in this tread?
Thanks in advance
Lorax: If you can refute any of Steve's findings, by all means do so. Arguing with a "straw man" -- which is what you do when you imply that Steve thinks he's "refuted AGW" -- is a logical fallacy and frankly only makes you look uninformed. No rational, honest mind that reads what Steve posts at Climate Audit would conclude that Steve claims to have "refuted AGW".
What he HAS done is to demonstrate that a number of the core "findings" that have been put forth in support of the AGW theory are fundamentally flawed -- and that in many cases, the same flaws exist in all the studies purporting to be "independent replications" of the study in question.
And in the process of demonstrating these flaws, Steve has also shown that the authors of said studies frequently obstruct access to their data and their methodologies for years, thereby making it extremely difficult to replicate what they've done. Time and time again, when the data is finally released -- or when Steve is finally able to "reverse engineer" the results to identity how they got to their conclusions -- it becomes apparent that the study's conclusions simply are not justified or are not known with anywhere near the level of certainty claimed in the original study.
It is also quite telling to me that almost none of the authors of the studies that Steve has shown to be flawed ever come to Climate Audit to defend their work -- and this is despite the fact that Steve has offered to give them a password so they create and post their own articles defending their work against Steve's criticisms. If Steve is "so wrong" , why don't they come to Climate Audit and embarass him? Should be easy if they are right -- but I've never seen a one of them do it.
As for concluding that AGW is a "hoax", each of us must decide for ourselves what credtiblity to give to the alarmists claims. The fact that they almost universally withold their data and refuse to release the details of their methodology destroys their credibility in my eyes. You may decide differently if you wish. But you have no right to mislead third parties reading this blog by misrepresenting Steve's positions.
Roly: For a good, non-technical summary of the Mann hockey stick story, go here:
http://www.uoguelph.ca/~rmckitri/research/McKitrick-hockeystick.pdf
It's written for the layman.
FordPrefect: "Hockey sticks are unimportant unless you play hockey. The real data still shows an increasing temperature which has a good chance of being due to human activities."
Where is this warming you speak of? Even the IPCC accepts there has been no warming since 1998. So what "real data" are you referring to?
"Hockey sticks are unimportant unless you play hockey"
I seem to recall that they were very important to AGW supporters and their political chums. Until last week, anyway.
Comment from Briffa himself: http://www.cru.uea.ac.uk/cru/people/briffa/yamal2000/
Mr Hill
Thanks for your insight. I have followed this story for a very long time and have been a lurker at Steve's sight for even longer. It seems to me that many of the protaganists on your site, and this is my first visit, are assigning motives to Steve's work for which the evidence simply does not exist. Steve M, and I don't talk for him: I nor anyone else , has that right, but he has to my knowledge never tried to falsify AGW. His sole ambition has been to 'audit', in the words purest form, the work presented by BOTH side of the climate change argument in an attempt to verify their results. It just so happens that all the problems of lack of openess, lack of data, lack of method and lack of communication has emenated from those 'scientists' who support AGW. In fact, Steve has said on several occasions that he believes that humans HAVE contributed to the current warming but because of the poor science demonstrated by his work he cannot be sure what that effect might be. There lies the rub. If we cannot be certain of our effects on the planet we may well be heading for disaster but are being blinded by the fraudulent output from so many of our previously trusted scientific organisations. That is criminel !! If this fraud is ever fully exposed, and I have my doubts, I would like to see all those involved banished from any other form of paid research. I won't happen though, will it?
I have looked at Briffa's response and it's not a response. He has affectively put the question on hold for further thought and rightly so. But I would want to see a pre-defined method for the selection of data and a description of how they applied that selection criteria before looking closely at the data for that is how genuine science works. You do not look at the data in detail before defining the criteria for its' selection.
Again I ask him and everyone else to READ carefully all Steve Ms words. And am I scientist? Well I was. Retired physicist, electrical, electronic, radio comms and telecomms engineer and I saw a lot of the same things as I am seeing now. Papers quoting other papers that never existed or that were subsets of the same etc. None of this is new sadly.
Giovanni, the methods they used are different, so are not a useful comparison beyond the number of core counts in the sample. The H&S data would be useful if they provided all the data on all the samples they collected.
John Lish, I can find no evidence of warming in the area of Yamal in the late 20th century. I looked at Sakhelard station.
For those who believe that McIntyre is not on a crusade. Please consider/explain this fact.....almost all of his critique is directed at papers which are related in some shape or form to AGW. Audit, if done in a fair and unbiased manner should be random. This is not what McIntyre is doing, that much should be obvious. McIntyre initially went after Mann et al. b/c he wanted to try and demonstrate that the MWP was warmer than current SATs, and so, convince others that there is nothing to worry about in terms of AGW. Now that his analysis can't show that he has shifted focus to the 20th century, well, we do not need proxy data for the 20th century Mr. McIntyre.
I never came to this thread claiming to be an expert on proxy data, so perhaps some of the more informed readers could answer me this. Did Briffa choose those records which showed warming b/c that is indeed what the regional climate was doing in the 20th century? If a proxy was not reflecting recent warming/cooling does it not call into question the validity of that particular proxy? Should the proxy be first checked to see whether or not it reflects the most recent, and observed, temperature record for that region? If not, then should it not be left out of the analysis as bad/corrupt/suspect data?
Mike N, please give me a number (e.g., global SAT, or global temp anomaly wrt to the 1960-1990 window from Steve's data) demonstrating to us that temperatures in the MWP were warmer than those measured in 1970-2005 (this is arbitrary, but my point is late 20th global century SATs). And I am not talking about a singular spike from a singular tree or even region, but a statistically significant warm period lasting decades. I'll ask the same question on CA.
Joe 90, do you deny that 10 of the warmest year sin the instrumented record all occurred post 1997? Plot the data, you can get them off the net and then apply a 10-year running mean (we are not worried about year-to-year variability from internal climate modes here). I have done so and for the life of me I cannot see any "cooling". Have the global mean annual **positive SAT anomalies** plateau since 2005 or so, then the answer is yes. But that proves nothing. Look at the 130 year record, there are numerous examples of short bursts of cooling followed by warming, the overall long-term SAT trend is up. Please stop obfuscating.