UPDATE: The Climate Audit server is getting hit with heavy traffic and is slow. If anyone has referenced graphs in blog posts or news articles lease see the mirrored URL list for the graphs at the end of this article and please consider replacement in your posting. I’ve also got a mirrored article of the Climate Audit post from Steve McIntyre. -Anthony
UPDATE2: Related articles
Update: A zoomed look at the broken hockey stick
A look at treemometers and tree ring growth
===
We’ve always suspected that Mann’s tree ring proxies aren’t all they are cracked up to be. The graph below is stunning in it’s message and I’m pleased to present it to WUWT readers. I’m sure the Team is already working up ways to say “it doesn’t matter”.
The QOTW this week centers around this graph:
The quote of the week is:
I hardly know where to begin in terms of commentary on this difference.
– Steve McIntyre, Climate Audit in Yamal: A “Divergence” Problem
The graph above shows what happens to the “Hockey Stick” after additional tree ring data, recently released (after a long and protracted fight over data access) is added to the analysis of Hadley’s archived tree ring data in Yamal, Russia.
All of the sudden, it isn’t the “hottest period in 2000 years” anymore.
Steve writes:
The next graphic compares the RCS chronologies from the two slightly different data sets: red – the RCS chronology calculated from the CRU archive (with the 12 picked cores); black – the RCS chronology calculated using the Schweingruber Yamal sample of living trees instead of the 12 picked trees used in the CRU archive. The difference is breathtaking.
I’ll say. Ding Dong the stick is dead.
This comparison to CRU archive data illustrates the most extreme example of scientific cherry-picking ever seen. As Steve writes in comments at CA:
Also keep in mind the implausibly small size of the current portion of the Yamal archive. It would be one thing if they had only sampled 10 trees and this is what they got. But they selected 10 trees out of a larger population. Because the selection yields such different results from a nearby population sample, there is a compelling prima facie argument that they’ve made biased picks. This is rebuttable. I would welcome hearing the argument on the other side. I’ve notified one dendro of the issue and requested him to assist in the interpretation of the new data (but am not very hopeful that he will speak up.)
See the complete report on this new development in the sordid story of tree ring proxies used for climate interpretation at Climate Audit. And while you are there, please give Steve a hit on the tip jar. With this revelation, he’s earned it.
The next time somebody tells you that tree rings prove we are living in the “hottest period in 2000 years” show them this graph and point them to this Climate Audit article.
Here’s a “cliff’s notes” summary written by Steve’s partner in publication, Ross McKitrick:
Here’s a re-cap of this saga that should make clear the stunning importance of what Steve has found. One point of terminology: a tree ring record from a site is called a chronology, and is made up of tree ring records from individual trees at that site. Multiple tree ring series are combined using standard statistical algorithms that involve detrending and averaging (these methods are not at issue in this thread). A good chronology–good enough for research that is–should have at least 10 trees in it, and typically has much more.
.
1. In a 1995 Nature paper by Briffa, Schweingruber et al., they reported that 1032 was the coldest year of the millennium – right in the middle of the Medieval Warm Period. But the reconstruction depended on 3 short tree ring cores from the Polar Urals whose dating was very problematic. http://www.climateaudit.org/?p=877.
2. In the 1990s, Schweingruber obtained new Polar Urals data with more securely-dated cores for the MWP. Neither Briffa nor Schweingruber published a new Polar Urals chronology using this data. An updated chronology with this data would have yielded a very different picture, namely a warm medieval era and no anomalous 20th century. Rather than using the updated Polar Urals series, Briffa calculated a new chronology from Yamal – one which had an enormous hockey stick shape. After its publication, in virtually every study, Hockey Team members dropped Polar Urals altogether and substituted Briffa’s Yamal series in its place.
http://www.climateaudit.org/?p=528. PS: The exception to this pattern was Esper et al (Science) 2002, which used the combined Polar Urals data. But Esper refused to provide his data. Steve got it in 2006 after extensive quasi-litigation with Science (over 30 email requests and demands).
3. Subsequently, countless studies appeared from the Team that not only used the Yamal data in place of the Polar Urals, but where Yamal had a critical impact on the relative ranking of the 20th century versus the medieval era.
http://www.climateaudit.org/?p=3099
4. Meanwhile Briffa repeatedly refused to release the Yamal measurement data used inhis calculation despite multiple uses of this series at journals that claimed to require data archiving. E.g. http://www.climateaudit.org/?p=542
5. Then one day Briffa et al. published a paper in 2008 using the Yamal series, again without archiving it. However they published in a Phil Tran Royal Soc journal which has strict data sharing rules. Steve got on the case. http://www.climateaudit.org/?p=3266
6. A short time ago, with the help of the journal editors, the data was pried loose and appeared at the CRU web site. http://www.climateaudit.org/?p=7142
7. It turns out that the late 20th century in the Yamal series has only 10 tree ring chronologies after 1990 (5 after 1995), making it too thin a sample to use (according to conventional rules). But the real problem wasn’t that there were only 5-10 late 20th century cores- there must have been a lot more. They were only using a subset of 10 cores as of 1990, but there was no reason to use a small subset. (Had these been randomly selected, this would be a thin sample, but perhaps passable. But it appears that they weren’t randomly selected.)
http://www.climateaudit.org/?p=7142
8. Faced with a sample in the Taymir chronology that likely had 3-4 times as many series as the Yamal chronology, Briffa added in data from other researchers’ samples taken at the Avam site, some 400 km away. He also used data from the Schweingruber sampling program circa 1990, also taken about 400 km from Taymir. Regardless of the merits or otherwise of pooling samples from such disparate locations, this establishes a precedent where Briffa added a Schweingruber site to provide additional samples. This, incidentally, ramped up the hockey-stickness of the (now Avam-) Taymir chronology.
http://www.climateaudit.org/?p=7158
9. Steve thus looked for data from other samples at or near the Yamal site that could have been used to increase the sample size in the Briffa Yamal chronology. He quickly discovered a large set of 34 Schweingruber samples from living trees. Using these instead of the 12 trees in the Briffa (CRU) group that extend to the present yields Figure 2, showing a complete divergence in the 20th century. Thus the Schweingruber data completely contradicts the CRU series. Bear in mind the close collaboration of Schweingruber and Briffa all this time, and their habit of using one another’s data as needed.
10. Combining the CRU and Schweingruber data yields the green line in the 3rd figure above. While it doesn’t go down at the end, neither does it go up, and it yields a medieval era warmer than the present, on the standard interpretation. Thus the key ingredient in a lot of the studies that have been invoked to support the Hockey Stick, namely the Briffa Yamal series (red line above) depends on the influence of a thin subsample of post-1990 chronologies and the exclusion of the (much larger) collection of readily-available Schweingruber data for the same area.
MIRROR URL’s FOR MAIN GRAPHICS IN THE CLIMATE AUDIT POST:
If anyone has referenced the Yamal graphs at CA in blog posts, please use these URL’s so that they get loaded from WordPress high traffic server.
http://wattsupwiththat.files.wordpress.com/2009/09/count_comparison1.gif
http://wattsupwiththat.files.wordpress.com/2009/09/rcs_chronologies_rev2.gif
http://wattsupwiththat.files.wordpress.com/2009/09/rcs_merged_rev2.gif
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Put this most recent revelation into context with the fact that CRU has not only “lost” the surface data that supposedly backs up these tree ring studies, they have “lost” the list of original stations so the original data set can not be recreated.
So BOTH sets of data that supposedly show 20th century AGW turn out to be nothing.
How many of YOUR dollars is YOUR local government spending on “fighting global warming” this year?
KimW (22:55:35) :
“This is a body blow to Science. For all the wisdom spoken about how science is impartial, here is proof that papers were published to give a desired result, and not what was there.”
Nonsense. What do you think people like Steve and Anthony are doing, tatting? Quite the opposite, it shows that scientific analysis properly applied catches bad or even fraudulent analysis quite elegantly. What it IS a body blow to is the clique-ish definitions of “peers” being used to limit who should review papers. There’s nothing “special” about the statistical methods used in climatology that a statistician wouldn’t understand. Nor is there anything about trees and tree growth that a climatologist would know that a forester wouldn’t, and wouldn’t know better.
DENDO-CHRONOLOGY ?? Isn’t that what tree ringers call their niche of bio-science ?
Not being a Latin/French/Greek/Whatever scholar, I would have to get out my dictionary to find out what dendo means but I would wild guess it as something to do with rings or layers or something like that.
But chronology I think I understand, and the one thing I think tree rings are good for is for telling the age of any particular ring on a tree, so long as you have all of them to the surface.
Last time I checked, if you bore a core out of a tree, it is fairly common to succeed in getting at least the outermost ring. You may not hit the center of the tree, and get that first year of its birth; unless you cut the tree down; but it is reasonable to expect that you can get all the layers from the present back to some innermost ring that your core drill cuts into.
Perhaps Dendo-chronology’s most famous success has been the correction of the Radia-carbon dating time scale. Originally based on a completely unwarranted assumption that the production of C14 from N14 in the atmosphere by incoming particles, happened at an absolutely constant rate. It was then assumed that the percent of C14 in the atmosphere remained fixed, and was taken up by trees and other plants.
Since you can actually count the rings down from the tree surface; you have a pretty good chance of getting the age of any ring right to the year; so by carbon dating that ring or at least measuring the radiocarbon C14 in it, you can connect the acytual counted date, to the C14 half life imputed date.
That correction had a major impact on the understanding of some important human history, by correctly dating the appearance of certain pottery technologies.
So dendochronology has earned its place in science history.
But now we have tree rings being used as proxies for almost any other physical parameter someone wants to get a time line on.
So we have all the arguments as to whether tree ring growth rates and cellular structure depend, on Temperature, rainfall, sunlight exposure, ground mineral content, wind patterns and so on and on.
Well other than the poor degreed idiot who cut down the oldest known Bristlecone Pine on earth in order to determine its age at the time of execution; I have a high degree of confidence that tree ringers are pretty good at dating tree rings; either by cutting the tree down, which is usually fatal to the tree; or better still by core boring.
But core boring, and treeslaughter demonstrate only too vividly, why tree rings should not be used as proxies for anything but the age of tree rings.
Anyone who has ever examined a sizeable treeslice, perhaps at one of the better known national forest museam type places, can immdeiately discern the problem.
TREE RINGS AREN’T THE SAME WIDTH ALL THE WAY ROUND THE TREE !
What’s more, if you take a cut tree and slice it into wafers; you will also find out that tree rings aren’t the same width all the way up the tree either; so in general, the width and structure of any core bored ring segment, will vary significantly with height above the ground, and position around the circumference of the tree.
Core boring of a tree to get a ring sample, is a classic case of failure to observe the rules of sampled data systems; the Nyquist theorem problem.
If you had core drilled on the Elandsfontein farm, 20 miles north-east of Pretoria in 1905; not knowing where you were; and your rock core had brought up a 3,106 carat diamond crystal ; you might have jumped to the conclusion that there was a whole layer of such huge rocks down there. Well you likely would have been shot dead on the spot, by the owner of the famous Premier Mine; a chap named Thomas Cullinan. There’s a good chance that your accidental choice of where to drill the hole actually resulted in merely whacking off that smaller 3,106 carat piece of what is believed to have been a much larger diamond. The remaining piece of the Cullinan Diamond was never found; but the cleavage face on the piece that was found inside the Premier Mine, imbedded visibly in the wall, proves it was part of a larger stone.
Well core drilling into trees may not be as lucrative as diamond mines, but the sampling process is just as hazardous, in terms of making unwarranted assumptions based on inadequate sampling.
So Steve’s new essay here is just a part of the problem of relying on tree rings; at least from core drilling, for anything other than the approximate age of the ring.
What is “wanker” in climatese? [snip]
I tried to be a bit more round about on CiF.
In response to one post:
” Malchemy:
@deniers, please be so kind as to put you favourite “refutation” into google and have a look at what comes out…”
I replied:
“OK, my favourite current Google search term is “McIntyre Yamal hockey stick”.
Enjoy.”
A few more “recommends” might encourage people to try the search for themselves before it gets deleted.
It appears an onslaught of referrals from Ace of Spades HQ, and perhaps here has crashed Steve’s server. Didn’t he just rebuild it recently?
Dang, looks like Climate Audit is swamped. Can’t get through to the site anymore. This is a huge story, possibly the most important blog posting so far this century.
I still don’t see how Briffa graph shows 1032 as “coldest in the millennium”? Looks elevated to me.
Might be time to raise the bandwidth limit at CA 🙂
“Didn’t he just rebuild it recently?”
I believe Anthony rebuilt it.
REPLY: problem now is number of database connections, working on it – A
@Foxgoose
I saw your Guardian post earlier today and thought that won’t be up for long, as Geoff chambers pointed out. Geoff I think you used to be a regular poster there. Unfortunately I have been moderated many times only to fight again.
Comment is free if you agree?
Now to matters in hand, Ding Dong Leslie Phillips is alive but the hockey stick is not broken it is intact and in a shape us poor souls always thought it should be?
We delude ourselves because my Gav and his mates are very clever, they new that about the unused data all along and of course the data was excluded for very good reasons.
He’s a lovely boy and has an answer for everything.
The results using the data do not accord with the models and the long term trends as determined by Professor B Blocks, PhD Camel hygiene at the University of Noscience, Rockall, Uk
Guys and Gals for goodness sake please don’t tell Steve what to do:-)
Robinson (09:23:32) wrote:
“If you haven’t already, it’s time to write to your MP, Senator, Congressman, representative, etc.”
I suggest the “etc.” include Penn State University, the current home of Dr. Michael Mann.
Today is a good day indeed.
Crosspatch, don’t you mean “teh most important blog post THIS MILLENNIUM!!one!1”?
But if this IS going to be the century of changing every national economy for the sake of Green Jobs, before we have to clean up after those mistakes throughout the 22nd century, then you’re probably right. Although I’d personally nominate Lee Harris’s “Civilization and Its Enemies” as a more important essay.
I predict that the response will be in the form of an ad hominem. Following the lawyer rules
1) If you have the law, argue the law
2) If you don’t have the law, argue the facts
3) If you don’t have the facts or the law, attack the person.
@ur momisugly Artwest
It won’t be on the site for long?
My guess is 1 hour max.
You mentioned words the Gurdian cannot cope with, hence my expulsion all the time for telling the headmaster to stop playing with himself:-)
I have pushed my luck so I better go before the Cat AW comes back?
I have a feeling that the real turning point will come as soon as the ‘AGW Faithful’ start sensing that they’ve been betrayed, or lied to, by their high priests. Hell hath no fury like a woman scorned, or believers who discover that their idols have feet of clay.
I wonder how long it will take before the pro-AGW media do an about-turn.
tokyoboy (00:55:35) :
I was citing from memory… this is why I put an interrogation mark after Japan. But thanks for clarifying.
I’m reminded of a statistics saying: in God we trust, everyone else brings data.
Paul Vaughan (23:29:25) :there is the ominous risk of triggering a backlash that will leave the door wide open for an era of political corruption.
Paul, what do you call what is going on right now, if not political corruption? It certainly has nothing to do with science.
“Well I’m starting a lively exchange”
Jerome, it appears there are a whole bunch of deleted posts over there….
Re: Main Topic: I suspect that the ‘official’ reply to this will be something to the effect that the modern tree-ring data is not valid because tree-growth during this era has been stunted by man-made industrial pollution.
I read the post and comments at climateaudit and I do agree that there are issues that need to addressed. Specifically, why the subset of ten chronologies were chosen and why the others were discarded. Could these ten just be the best calibrated to recent measured temps? Can one assume that treemometers preserve this calibration or do they cycle in and out? I am not a dendrochronologist so I do not know. As scientists though, we need to make sure that our methods are transparent and it appears this might not the case with Yamal data and methods.
Something that should also be understood is that the Mann et al. 2008 paper reproduces the hockey stick without using tree rings. Here is the abstract and the entire paper is free to download at:
http://www.pnas.org/content/early/2008/09/02/0805721105.abstract
Following the suggestions of a recent National Research Council report [NRC (National Research Council) (2006) Surface Temperature Reconstructions for the Last 2,000 Years (Natl Acad Press, Washington, DC).], we reconstruct surface temperature at hemispheric and global scale for much of the last 2,000 years using a greatly expanded set of proxy data for decadal-to-centennial climate changes, recently updated instrumental data, and complementary methods that have been thoroughly tested and validated with model simulation experiments. Our results extend previous conclusions that recent Northern Hemisphere surface temperature increases are likely anomalous in a long-term context. Recent warmth appears anomalous for at least the past 1,300 years whether or not tree-ring data are used. If
tree-ring data are used, the conclusion can be extended to at least the past 1,700 years, but with additional strong caveats. The reconstructed amplitude of change over past centuries is greater than hitherto reported, with somewhat greater Medieval warmth in the Northern Hemisphere, albeit still not reaching recent levels.
Another tidbit from the Mann et al. (2008) paper is:
It is intriguing to note that the removal of tree-ring data from the proxy dataset yields less, rather than greater, peak cooling during the 16th–19th centuries for both CPS and EIV methods (see Figs. S5a and S6b, respectively), contradicting the claim (33) that tree-ring data are prone to yielding a warm-biased ‘‘Little Ice Age’’ relative to reconstructions using other high-resolution climate proxy indicators.
Ding, dong, the stick might not be wrong. 🙂
Scott A. Mandia:
Mann 2008 shows an uptick under only if they include the inverted tiljander proxy or if they include the stripbark bristlecone pines which the NAS proscribed. Mann plays three proxy Monte.
Studies which likely should be revised but are unlikely to be are:
Briffa 2000, Mann and Jones 2003; Bradley, Hughes and Diaz 2003; Jones and Mann 2004; Moberg et al 2005; D’Arrigo et al 2006; Osborn and Briffa 2006; Hegerl et al 2007; Briffa et al 2008; Kaufman et al 2009. Esper 2002 ; Juckes 2007
These are the “dozens” of “independent” studies confirming Mann’s work.
Scott Mandia,
Yes, the hokey stick is dead. That’s easy to prove.
Even that propaganda organization, the UN/IPCC, deleted Mann’s hokey stick from AR-4. Why? Because McKitrick and McIntyre, independently verified by Prof Wegman, thoroughly debunked it.
The IPCC loved Mann’s hockey stick! And you don’t boot out something you truly love. It was visually better than any of the subsequent imitations in AR-4. With Mann’s chart, anyone could see at a glance that climate catastrophe was headed our way. It was frightening!
But the IPCC was forced to delete Mann’s hokey stick — because it was bogus. So, ding dong, the stick is wrong.
I find it hard to understand the concept of “best calibrated”. You can’t calibrate a tree, can you? If you’re finding those that most closely match the instrumental record, what have you gained by doing the study in the first place? If you have 100 trees and 90 of them don’t match the record, you have a problem. Chosing the 10 that do holds no significance. They may match it purely by chance!
This is my understanding of the situation. Please correct me if I’m wrong.
Anthony
See your intro.
He may well have Staved them but his name is Steve:-) No need to post this.
Reply: Fixed ~ ctm