For those that don’t read a lot of the WUWT comments closely, there has been a scholarly argument going on between Tom P of the UK and several WUWT commentators over the methodology Steve McIntyre used to illustrate the “breathtaking difference” between the plot of the hand picked set of 12 Yamal trees and the larger Schweingruber tree ring data set also from Yamal. Tom P. reworked Steve’s R-code script (which he posted on WUWT) to include both the 12 excluded and the Schweingruber and thought he found “insensitivity to additional data”, saying “There is no broken hockeystick”.
Jeff Id audited the auditor of an auditor and found that Steve’s work still holds up “robustly”. – Anthony
Just a short post tonight I hope. Tom P, an apparent believer in the hockey stick methods posted an entertaining reply to Steve McIntyre’s recent discoveries on Yamal. He used R code to demonstrate a flaw in SteveM’s method. His post was on WUWT, brought to my attention by Charles the moderator and is copied here where he declares victory over Steve.
Steve McIntryre’s [sic] reconstructions above are based on adding an established dataset, the Schweingruber Yamal sample instead of the “12 trees used in the CRU archive”. Steve has given no justification for removing these 12 trees. In fact they probably predate Briffa’s CRU analysis, being in the original Russian dataset established by Hantemirov and Shiyatov in 2002.
One of Steve’s major complaint about the CRU dataset was that it used few recent trees, hence the need to add the Schweingruber series. It was therefore rather strange that towards the end of the reconstruction the 12 living trees were excluded only to be replaced by 9 trees with earlier end dates.
I asked Steve what the chronology would look like if these twelve trees were merged back in, but no plot was forthcoming. So I downloaded R, his favoured statistical package, and tweaked Steve’s published code to include the twelve trees back in myself. Below is the chronology I posted on ClimateAudit a few hours ago.
TomP' s plot. Click to enlarge Source: http://img80.yfrog.com/img80/1808/schweingruberandcrud.png
The red line is the RCS chronology calculated from the CRU archive; black is the chronology calculated using the Schweingruber Yamal sample and the complete CRU archive. Both plots are smoothed with 21-year gaussian, as before. The y-axis is in dimensionless chronology units centered on 1.
It looks like the Yamal reconstruction published by Briffa is rather insensitive to the inclusion of the additional data. There is no broken hockeystick.
Jeff Id’s version of TomP’s graph – Click to expand
I spent some time tonight looking at his results. Time planned for analyzing Antarctic sea ice. I found that essentially the only difference in the operating functions of the code is the following line.
.
Steve M —- tree=rbind(yamal[!temp,],russ035)
Tom P —– tree=rbind(yamal,russ035)
.
The !temp in Steve’s line removes 12 series of Yamal for the average while Tom’s version includes it. I’m all for inclusion of all data, but I am a firm believer that Briffa’s data is probably a cherry picked set of trees to match temp or something. Therefore by inclusion of the sorted Briffa Yamal version, we have an automatic exclusion of data which would otherwise balance the huge trend. However, this is not the problem with Tom’s result. The problem lies in this plot, also created by Tom P’s code.
Tom P’s Yamal Reconstruction – Count per Year. Click to Expand
Here is the zoomed in version:
Above we can see that everything in TomP’s curve after 1990 is actually 100% Briffa Yamal data.
So the question becomes – What does the series look like if the Yamal data doesn’t create the ridiculous spike at the end the curve?
I truncated the black line at 1990 below.
The black line is truncated at the end of the Schweingruber data and it looks pretty similar to the graph presented in the green line by Steve McIntyre again below.
Don’t be too hard on Tom P, he honestly did a great job and took the time to work with the R script which is more than most are willing to. Steve is a very careful worker though and it’s damn near impossible to catch him making mistakes. Trust a serious skeptic, it’s not easy to find mistakes in his work and some of us check him just as I spent over an hour checking Tom’s work. In my opinion Tom deserves congratulations for his efforts and checking, this way we all learn.
I’ve now been all the way through SteveM’s scripts from beginning to end and can’t find any problems with the script, maybe others can!
There are 252 distinct series in the CRU archive. There are 12 IDs consisting of a 3-letter prefix, a 2-digit tree # and 1-digit core#. All 12 end in 1988 or later and presumably come from the living tree samples. The nomenclature of these core IDs url (POR01…POR11; YAD04…YAD12; JAH14…JAH16 – excluding the last digit of the ID here as it is a core #) suggests to me that there were at least 11 POR cores, 12 YAD cores and 16 JAH cores.
It is “possible” that they skipped ID numbers, but this is a farfetched theory even for Tom. As surmised here, the missing ID numbers are “evidence” of at least 39 cores and that the present archive is not only too small, but incomplete.
I am online too much, but I am not online 24/7. I’ve been out playing squash. Surely I’m allowed to be offline occasionally without a poster commenting adversely on this.
While I was out, CA crashed as well. Thus, it was “quiet.
Contrary to Tom’s speculations and misrepresentation of my statements, it is my opinion that there is considerable evidence that the 12 cores are not a complete population i.e. that they have been picked form a larger population. Rather than quote form actual text, Tom puts the following words in my mouth that I did not say:
Steve McIntyre said they may well have been just the most recent part of Hantemirov and Shiyatov’s dataset and no selection would have been made.
This is not my view.
The balance of Tom’s argument is:
No, they are the twelve most recent cores. There’s been no evidence provided to suggest they are in any way suspect. ..There is no obvious reason to exclude them.
I disagree. I do not believe that they constitute a complete population of recent cores. As a result, I believe that the archive is suspect. There is every reason to exclude them in order to carry out a sensitivity as I did. The sensitivity study showed very different results. I do not suggest that the sensitivity run be used as an alternative temperature history. Right now, there are far too many questions attached to this data set to propose any solution to the sampling conundrum. It’s only been a couple of days since the lamentable size of the CRU sample became known and it will take a little more time yet to assess things.
Reasons why I “suspect” that a selection was made from a larger population include the following. A field dendro could take 12 cores in an hour. We took a lot more than that at Mt Allegre and a field dendro could be far more efficient. Thus, it seems very unlikely that the entire population of cores from the Yamal program is only 12 cores and on this basis, it is my surmise that a selection was taken from the cores. Standard dendro procedures use all crossdated cores and definitely use more than 10 cores if they are available.
This doesn’t “prove” that a selection was made, but it is reasonable to “suspect” that a selection was made and to ask CRU and their Russian associates to provide a clear statement of their protocols. There’s no urgency to do anything prior to receiving a statement of their sampling protocols. For this purpose, it doesn’t matter a whit whether the selection was made by the Russians or at CRU or a combination. In my first post on this matter – which Tom appears not to have read, I canvass the limited evidence for and against. There is certainly evidence supporting the idea that the 12 cores were among 17 selected by the Russians, but in other parts of the data set, the CRU population is larger than that used in the Hantemirov and Shiyatov chronology. The construction of the CRU data set is not described in any literature; the description in Hantemirov and Shiyatov has something to do with it, but doesn’t yield the CRU data data set. Some sort of reconciliation is required.
In addition, the age distribution of the CRU 12 is very different than the age distribution from the nearby Schweingruber population. In my opinion, the uniformly high age of the CRU12 relative to the Schweingruber population is suggestive of selection – in this respect, perhaps and even probably by the Russians. Again this isnt proof. Maybe they were just lucky 12 straight times and, unlike Schweingruber, they got very long-lived trees with every core. Without documentaiton, no one knows. In any event, this doesn’t help the Briffa situation. If these things are temperature proxies, the results from two different nearby populations should not be so different and protocols need to be established for ensuring that the age distribution of the modern sample is relatively homogeneous with the subfossil samples (and they aren’t.)
The prevailing dendro view is that an RCS chronology requires a much larger population than a “conventional” standardization. Thus, even if the data set had been winnowed down to 10 cores in 1990 and 5 cores at the end, this is an absurdly low population for modern cores, which are relatively easily obtained. Use of such small replication is inconsistent with Briffa’s own methodological statements.
Tom also misses a hugely important context. There is a nearby site (Polar Urals) with an ample supply of modern core. Indeed, at one time, Briffa used Polar Urals to represent this region. My original question was whether there was a valid reason for substituting Yamal for Polar Urals. The microscopic size of the modern record suggests that there was not a valid reason. However, this tiny sample size was not known to third parties until recently due to Briffa’s withholding of data, not just from me, but also to D’Arrigo, Wilson et al.
Until details of the Yamal selection process are known, my sense right now is that one cannot blindly assume – as Tom does – that what we see is a population. Maybe this will prove to be the case, but personally I rather doubt it. A better approach is to use the Polar Urals data set as a building block.
As to Tom’s argument that none of this “matters”, the Yamal data set has a bristlecone-like function in a number of reconstructions. While the differences between the versions may not seem like a lot to Tom, as someone with considerable experience with this data, it is my opinion that the revisions will have a material impact on the medieval-modern difference in the multiproxy studies that do not depend on strip bark bristlecones.
Richard (23:08:47) : “until shot down by the “Texas sharpshooters” on CA”
Richard, if you understand what the Texas Sharpshooter fallacy is about, you will also understand that it is not a compliment to Steve McIntyre and CA even though you meant it that way.
PR Guy
September 30, 2009 12:34 pm
Re: RD
“Its time to move on”
No don’t move on. In the PR world, there’s a thing called a ‘cleaner’. This is a person, usually a domain expert, who PR firms use to create confusion and doubt. Logically, Fenton Communications will respond to any serious challenge of the Hockey Stick by sending in a cleaner. This person’s job will be to try to discredit Steve’s analysis, or, failing that, to simply create the appearance of controversy.
The press will not be able to understand why his arguements are specious, they’ll simply take away a mistaken view that Steve’s analysis might not be right. That’s a cleaner’s objective.
I’m not saying that Tom P is a cleaner; I’m just observing that he is behaving in cleaner-like ways. He’s clearly working on this full-time. He’s a domain expert who should know better than to make such ridiculous arguements. The truth is not the objective.
Don’t expect him to give any ground. Continue to engage him and to point out the errors in his arguement. Don’t give him the last word.
Congratulation to Steve McIntryre for finding the “secret sauce”
J. Peden
September 30, 2009 1:13 pm
Tom P.: Shouldn’t suspicion fall on this core archive as well? Excluding one subset of a core archive on the basis of incomplete label sequences [presumably Briffa’s Yamal 12] but including another series with the broken label sequences [russ035 NCDC archive] might lead to accusations of cherry picking, [or to at least a similarly questionable, uncertain statistical validity regarding any non-inclusive subset of the data].
Yes, exactly! Isn’t that why all the core data need to be released for purposes of replication, and likewise to allow a re-evaluation as to why certain cores were excluded or included?
Imo, Steve M.’s audit does demonstrate this main point, which simply involves the malleability or at least very tenuous nature of statistical correlations, making apparently “cherry picked” data suspect until proven otherwise by release of the data and subsequent review, which your above quote appropriately reiterates!
It seems to me that the alternative method, selecting out from a study population ex post facto only cores whose calibrational ring-widths “show” the more recent [global?, local?] warming, and which perhaps also give a flat past “temperature”, could theoretically lead to only one tree/core being dubbed a “correct” hockey stick treemometer, but a process which seems to me would then constitute an epitome of a wholly inappropriate, specifically directed misuse of correlation, and in fact the exact opposite of what statistical correlations are designed for:
– because this one “correct” ring-width pattern found during calibration could much more likely be simply adventitious, given the myriad of unanalyzed uncertain influences upon ring widths existing in the case of wild trees, which can also affect every other tree ring width in equally uncertain ways, a situation therefore affecting all study trees, which would actually be more proven by the rest of the data, in effect making each of the trees equal non-treemometers!
– thus the presence of only one “pristine” treemometer within a population would more validly lead to the opposite conclusion, that the whole tree population selected as possible treemometers, hyp.o, which includes the one allegedly valid treemometer, does not show ring width patterns that even [only] correlate with calibrational temps. [local?, global?], which should more rightly lead to rejection of hyp.o, and thus to the reasonable invalidation of the idea that the one alleged treemometer is actually a treemometer, the same as with the rest of the trees!
And in the case of there being more than one alleged treemometer in the population, aren’t there accepted statistical methods which show the probability that the correlation between numbers derived from one population, such as some subalpine “bog” larch ring widths – which nevertheless includes the more agreeable members’ numbers – with numbers from another population, of temperatures, are more likely due to “chance” or to multiple uncertain influences, than to a more encouraging statistically positive correlation between these numbers?
But how can anyone at all tell what the actual correlation might tend to be, based upon the data collected so far, if all of this data is not included in the calculations, and moreover is not even released?
kim
September 30, 2009 1:17 pm
Tom P, you need to get busy doing something useful, like explain to yourself and the world why Rob Wilson couldn’t get Briffa’s data years ago, when both he and Steve McIntyre knew he needed it. You should not be closing ranks; you should be exposing the wrongdoing. And the sooner the better. It’s the scientific thing to do.
===========================================
Dodgy Geezer
September 30, 2009 1:55 pm
“It should be called the “Yamal Briffa Affair”. Maybe for the movie?
“The Dendro Dozen””
Free the Briffa 12!
Tom P
September 30, 2009 3:15 pm
PR Guy (12:34:42) :
“He’s clearly working on this full-time. He’s a domain expert who should know better than to make such ridiculous arguements. The truth is not the objective.”
I feel both flattered and denigrated! But no, I am not a “cleaner”. REPLY: Tom since you’ve posted here at WUWT many times in the past using your full name, why not set the record straight and show people the optical and space hardware you actually work on. It is quite impressive. – Anthony
Tom,
On CA you admitted that your analysis was not appropriate for a sensitivity analysis.
Comment 351 on http://www.climateaudit.org/?p=7168
So I asked again.
So since you now admit that your method is not valid for a sensitivity test — do you now retract this statement based on your incorrect sensitivity analysis at WUWT: It looks like the Yamal reconstruction published by Briffa is rather insensitive to the inclusion of the additional data. There is no broken hockeystick
Tom P
September 30, 2009 4:40 pm
Jeff Id (16:03:48) : (crossposted from CA)
No, my statement stands. What I have presented is just a plotting of the full dataset.
But, I admit that unless there is data to contradict the post 1990 record, there will continue to be a very pronounced recent rise irrespective of any previous reconstruction.
However, if there are reasons to completely discount the post 1990 data, I have no reason to think the black line of your plot at: http://noconsensus.files.wordpress.com/2009/09/tomptruncsh.jpg
is not a reasonable reflection of the entire Yamal dataset.
One reason for discounting the last part of the dataset has been advanced, broken labelling core sequences. This has been shown to be specious – it would reject the Schweingruber series as well.
But Steve has stated another reason:
“Standard dendro practice requires a minimum number of cores depending on the consistency of the core “signal”.”
I’d like some specific numbers put on this with respect to the post 1990 data. If indeed these numbers show the minimum number has not been met, and this data should be completely discarded, I’m certainly willing to accept the black line of your plot above as a good reconstruction based on all the available data.
If you cannot reach the honesty level to admit your test says nothing about sensitivity, then I’m wasting my time discussing this with another AGW internet advocate.
Layman Lurker
September 30, 2009 7:15 pm
Tom P., the point of Steve’s analysis is to compare the Schweingruber data to the CRU data – a comparison which ends at 1990 and therefore must truncate post 1990 CRU because it is irrelevant. At this point you twist everything around and ask ridiculous questions about Steve’s reasons for dropping the post 1990 CRU when the answer seems obvious to everyone but you.
Carrick
September 30, 2009 9:28 pm
Tom P, what you have shown is if you only include the Briffa data, the result remains unchanged from when you only included the Briffa data.
WTF?
Want to play a game of “Begging the Question[tm]” anyone?
kim
September 30, 2009 10:10 pm
Tom P, don’t you wonder where the principal ‘peers’ involved in this train wreck are? Now, I know one of them is physically sick; are the others sick at heart? Why are you the lone voice disputing an apparently killer argument from Steve?
====================================
Tom P
October 1, 2009 1:08 am
Jeff Id (16:03:48) :
Steve McIntyre has put up the chronology records for all the core data from live trees in the CRU and Schweingruber series: http://www.climateaudit.org/?p=7241
While most of the CRU trees cover the entire plotted range back to 1800, and so are at least 190 years old, only 3 of the 18 Schweingruber are that old, and most are less than 100 years old.
Hence the Schweingruber series does not contain the long-lived trees necessary to discern a centennial or multicentennial variations. The Schweingruber series is therefore of very limited utility for a valid comparison with the much longer-lived trees of the CRU archive. Steve McIntyre’s sensitivity test between them is comparing a signal (CRU) to noise (Schweingruber).
Hence I am happy to withdraw my reconstruction based on the data from both series – the original Briffa plot stands unmodified. It is not the hockeystick of Briffa’s Yamal reconstruction that has collapsed, but rather the case against it.
>>So, let me get this straight… the faith of our economy and
>>politics rest in a few dozen old trees somewhere that grew
>>in a limited little spot on the earth?
And the fate of a few trillion dollars of our money, too.
.
>>Nature a scientific journal?
>>It has become an activist political mouthpiece.
Just like New Scientist and the BBC.
.
I have a small theory as to why. After the War (WWII) we had a great mass of journos, like Robert Capper et all, who were front-line soldier-jounos and real meat-eating men (and women too). They took over the BBC and media for a whole generation – spawning the likes of the peerless Raymond Baxter with good, honest scientific reporting.
But the media is generally a liberal art, and later candidates and employees were all from the liberal sector, if you see what I mean. So perhaps we should not be too surprised that liberal issues and agendas are now being pushed to the fore. A few more meat-eating graduates need to swallow some pride and apply the grease-paint.
.
kim
October 1, 2009 5:13 am
Tom P 1:08:11
So what do Briffa’s cherry picked trees show us the temperature was in the 20 Century and what do the nearby thermometers show?
Answer, the cherry, actually larch, orchard has a hockey stick and the instrumental record does not. Big problem. Maybe those better randomized young trees are better treemometers. More likely, it’s the randomization, which is the critical flaw with Briffa.
Do you get it? Non-randomized is cherry-picked.
=================================
kim
October 1, 2009 6:27 am
Ah, Keith Briffa has weighed in, see the link at the end of the Register thread at CA. I note that he is ambiguous about whether or not this series was compared to temperature to pick it. He claims not to be doing so now.
============================================
Tom-P said: Hence the Schweingruber series does not contain the long-lived trees necessary to discern a centennial or multicentennial variations. The Schweingruber series is therefore of very limited utility for a valid comparison with the much longer-lived trees of the CRU archive. Steve McIntyre’s sensitivity test between them is comparing a signal (CRU) to noise (Schweingruber).
Hence I am happy to withdraw my reconstruction based on the data from both series – the original Briffa plot stands unmodified. It is not the hockeystick of Briffa’s Yamal reconstruction that has collapsed, but rather the case against it.
…..Man, you’re swinging at the logic pinata, but only hitting the tree. This argument is is so bad, even I can see the gaping holes. Just because one paper is bad (in your opinion) doesn’t automatically make the other good. I ‘ll let someone else take over. I have to go to work.
BTW, On Briffa, I think you should check Steve’s latest post. It appears “The Blade of Briffa” is created by ONE tree!
Tom P
October 1, 2009 7:35 am
Cross-posted from CA:
Steve McIntyre:
“However, I disagree that the trees in the CRU archive are “much longer-lived”, other than the trees selected for the modern comparison.”
But the modern comparison was the subject of your original sensitivity analysis that was supposed to have broken the Yamal hockeystick!
All you have done is inject noise into the Biffra/H&S series by adding in much shorter lived trees. This also explains why the Schweingruber series did not well correlate with the instrumental temperature.
Tom P (07:35:54) :
This is a false interpretation of the standardizaton methods in tree rings. The net result of this reconstruction is a mean, nothing more. An average of the available data. There is no recentering, no RegEM no fancy PCA just an average of the ring widths as standardized by the same exponential function for every tree ring width.
Pretending that you have killed Steve’s work again (a third time) and again by weak arm waiving means nothing.
Layman Lurker
October 1, 2009 1:02 pm
re: Tom P (01:08:11)
“Steve McIntyre’s sensitivity test between them is comparing a signal (CRU) to noise (Schweingruber).”
And this is self-evident? Instead of arm waving, perhaps a little demonstration is in order before you pop the champagne corks.
Richard
October 1, 2009 4:21 pm
woodNfish (12:24:30) :
Richard (23:08:47) : “until shot down by the “Texas sharpshooters” on CA”
“Richard, if you understand what the Texas Sharpshooter fallacy is about, you will also understand that it is not a compliment to Steve McIntyre and CA even though you meant it that way.”
I do understand what the Texas Sharpshooter fallacy is all about. And by Texas Sharpshooters I meant the ones who exposed this fallacy to “shoot down” Tom P, not that they used the fallacy themselves. It was Tom P who used it. “Sharpshooters” and “shooting down” was used as the pun, after all sharpshooters are the guys who shoot down people.
Richard
October 1, 2009 6:16 pm
This is what I posted at Real Climate Richard says:
Your comment is awaiting moderation.
1 October 2009 at 6:44 PM
From what I understand of the Yamal chronology story, Briffa used 12 tree rings for the reconstruction of the 19th and 20th centuries – more for the 19th century and even less for the 20th.
This reconstruction shows a hockey-stick graph, where the current warm period is far warmer than any in the past 2,000 years. When all of Prof Briffa’s and the Schweingruber data is used, the graph is quite different. In this graph, whereas the current warm period shows up, the medieval warm period, for this complete data set, shows as warmer than the current warm period.
Now it was questioned why Prof Briffa used only 12 trees for the modern reconstruction and it was argued that these trees best agreed with modern instrumental records. And the criticism to this argument was that this amounted to cherry-picking and “sharp-shooting” – picking the data to get the result you wanted from the data, rather than letting the data give you the results.
To me this makes sense. From my high school science I was told that in a scientific experiment, you must record the data as it comes. You must in now way manipulate this data to predict its outcome, even though this outcome maybe expected.
This criticism appears to carry more weight when it appears that just one tree out of those 12 is responsible for most of the big warming of the current warm period.
What are your comments on this?
There have been 12 comments since then which have been published but mine is still “awaiting moderation”. Comments which include backslapping each other and tearing down “deniers” in somewhat unmoderated language.
When posed with real questions on the Yamal affair they appear to be perplexed on how to handle it.
Richard
October 1, 2009 6:21 pm
And it has now been moderated out. Leaving the field to others with comments like: Dan L. says:
1 October 2009 at 7:57 PM
>dhogaza: I’m glad that RC is hitting back.
Indeed.
McI is a coy, sneaky b… uh, fellow. He is cunning enough to avoid directly exposing his nitpicking to peer reviewed publication, relying instead on the usual suspects to shriek on his behalf. Congratulations to RC for knocking the pins from under the WUWTs of this world and their hockey stick obsessions.
Makes me laugh.
For those that don’t read a lot of the WUWT comments closely, there has been a scholarly argument going on between Tom P of the UK and several WUWT commentators over the methodology Steve McIntyre used to illustrate the “breathtaking difference” between the plot of the hand picked set of 12 Yamal trees and the larger Schweingruber tree ring data set also from Yamal. Tom P. reworked Steve’s R-code script (which he posted on WUWT) to include both the 12 excluded and the Schweingruber and thought he found “insensitivity to additional data”, saying “There is no broken hockeystick”.
Tom P’s Yamal Reconstruction – Count per Year. Click to Expand
![rcs_merged_rev[1]](http://noconsensus.files.wordpress.com/2009/09/rcs_merged_rev11.gif "rcs_merged_rev[1]")
Richard (23:08:47) : “until shot down by the “Texas sharpshooters” on CA”
Richard, if you understand what the Texas Sharpshooter fallacy is about, you will also understand that it is not a compliment to Steve McIntyre and CA even though you meant it that way.
Re: RD
“Its time to move on”
No don’t move on. In the PR world, there’s a thing called a ‘cleaner’. This is a person, usually a domain expert, who PR firms use to create confusion and doubt. Logically, Fenton Communications will respond to any serious challenge of the Hockey Stick by sending in a cleaner. This person’s job will be to try to discredit Steve’s analysis, or, failing that, to simply create the appearance of controversy.
The press will not be able to understand why his arguements are specious, they’ll simply take away a mistaken view that Steve’s analysis might not be right. That’s a cleaner’s objective.
I’m not saying that Tom P is a cleaner; I’m just observing that he is behaving in cleaner-like ways. He’s clearly working on this full-time. He’s a domain expert who should know better than to make such ridiculous arguements. The truth is not the objective.
Don’t expect him to give any ground. Continue to engage him and to point out the errors in his arguement. Don’t give him the last word.
Congratulation to Steve McIntryre for finding the “secret sauce”
Tom P.:
Shouldn’t suspicion fall on this core archive as well? Excluding one subset of a core archive on the basis of incomplete label sequences [presumably Briffa’s Yamal 12] but including another series with the broken label sequences [russ035 NCDC archive] might lead to accusations of cherry picking, [or to at least a similarly questionable, uncertain statistical validity regarding any non-inclusive subset of the data].
Yes, exactly! Isn’t that why all the core data need to be released for purposes of replication, and likewise to allow a re-evaluation as to why certain cores were excluded or included?
Imo, Steve M.’s audit does demonstrate this main point, which simply involves the malleability or at least very tenuous nature of statistical correlations, making apparently “cherry picked” data suspect until proven otherwise by release of the data and subsequent review, which your above quote appropriately reiterates!
It seems to me that the alternative method, selecting out from a study population ex post facto only cores whose calibrational ring-widths “show” the more recent [global?, local?] warming, and which perhaps also give a flat past “temperature”, could theoretically lead to only one tree/core being dubbed a “correct” hockey stick treemometer, but a process which seems to me would then constitute an epitome of a wholly inappropriate, specifically directed misuse of correlation, and in fact the exact opposite of what statistical correlations are designed for:
– because this one “correct” ring-width pattern found during calibration could much more likely be simply adventitious, given the myriad of unanalyzed uncertain influences upon ring widths existing in the case of wild trees, which can also affect every other tree ring width in equally uncertain ways, a situation therefore affecting all study trees, which would actually be more proven by the rest of the data, in effect making each of the trees equal non-treemometers!
– thus the presence of only one “pristine” treemometer within a population would more validly lead to the opposite conclusion, that the whole tree population selected as possible treemometers, hyp.o, which includes the one allegedly valid treemometer, does not show ring width patterns that even [only] correlate with calibrational temps. [local?, global?], which should more rightly lead to rejection of hyp.o, and thus to the reasonable invalidation of the idea that the one alleged treemometer is actually a treemometer, the same as with the rest of the trees!
And in the case of there being more than one alleged treemometer in the population, aren’t there accepted statistical methods which show the probability that the correlation between numbers derived from one population, such as some subalpine “bog” larch ring widths – which nevertheless includes the more agreeable members’ numbers – with numbers from another population, of temperatures, are more likely due to “chance” or to multiple uncertain influences, than to a more encouraging statistically positive correlation between these numbers?
But how can anyone at all tell what the actual correlation might tend to be, based upon the data collected so far, if all of this data is not included in the calculations, and moreover is not even released?
Tom P, you need to get busy doing something useful, like explain to yourself and the world why Rob Wilson couldn’t get Briffa’s data years ago, when both he and Steve McIntyre knew he needed it. You should not be closing ranks; you should be exposing the wrongdoing. And the sooner the better. It’s the scientific thing to do.
===========================================
“It should be called the “Yamal Briffa Affair”. Maybe for the movie?
“The Dendro Dozen””
Free the Briffa 12!
PR Guy (12:34:42) :
“He’s clearly working on this full-time. He’s a domain expert who should know better than to make such ridiculous arguements. The truth is not the objective.”
I feel both flattered and denigrated! But no, I am not a “cleaner”.
REPLY: Tom since you’ve posted here at WUWT many times in the past using your full name, why not set the record straight and show people the optical and space hardware you actually work on. It is quite impressive. – Anthony
Tom,
On CA you admitted that your analysis was not appropriate for a sensitivity analysis.
Comment 351 on http://www.climateaudit.org/?p=7168
So I asked again.
So since you now admit that your method is not valid for a sensitivity test — do you now retract this statement based on your incorrect sensitivity analysis at WUWT:
It looks like the Yamal reconstruction published by Briffa is rather insensitive to the inclusion of the additional data. There is no broken hockeystick
Jeff Id (16:03:48) : (crossposted from CA)
No, my statement stands. What I have presented is just a plotting of the full dataset.
But, I admit that unless there is data to contradict the post 1990 record, there will continue to be a very pronounced recent rise irrespective of any previous reconstruction.
However, if there are reasons to completely discount the post 1990 data, I have no reason to think the black line of your plot at:
http://noconsensus.files.wordpress.com/2009/09/tomptruncsh.jpg
is not a reasonable reflection of the entire Yamal dataset.
One reason for discounting the last part of the dataset has been advanced, broken labelling core sequences. This has been shown to be specious – it would reject the Schweingruber series as well.
But Steve has stated another reason:
“Standard dendro practice requires a minimum number of cores depending on the consistency of the core “signal”.”
I’d like some specific numbers put on this with respect to the post 1990 data. If indeed these numbers show the minimum number has not been met, and this data should be completely discarded, I’m certainly willing to accept the black line of your plot above as a good reconstruction based on all the available data.
If you cannot reach the honesty level to admit your test says nothing about sensitivity, then I’m wasting my time discussing this with another AGW internet advocate.
Tom P., the point of Steve’s analysis is to compare the Schweingruber data to the CRU data – a comparison which ends at 1990 and therefore must truncate post 1990 CRU because it is irrelevant. At this point you twist everything around and ask ridiculous questions about Steve’s reasons for dropping the post 1990 CRU when the answer seems obvious to everyone but you.
Tom P, what you have shown is if you only include the Briffa data, the result remains unchanged from when you only included the Briffa data.
WTF?
Want to play a game of “Begging the Question[tm]” anyone?
Tom P, don’t you wonder where the principal ‘peers’ involved in this train wreck are? Now, I know one of them is physically sick; are the others sick at heart? Why are you the lone voice disputing an apparently killer argument from Steve?
====================================
Jeff Id (16:03:48) :
Steve McIntyre has put up the chronology records for all the core data from live trees in the CRU and Schweingruber series:
http://www.climateaudit.org/?p=7241
While most of the CRU trees cover the entire plotted range back to 1800, and so are at least 190 years old, only 3 of the 18 Schweingruber are that old, and most are less than 100 years old.
Hence the Schweingruber series does not contain the long-lived trees necessary to discern a centennial or multicentennial variations. The Schweingruber series is therefore of very limited utility for a valid comparison with the much longer-lived trees of the CRU archive. Steve McIntyre’s sensitivity test between them is comparing a signal (CRU) to noise (Schweingruber).
Hence I am happy to withdraw my reconstruction based on the data from both series – the original Briffa plot stands unmodified. It is not the hockeystick of Briffa’s Yamal reconstruction that has collapsed, but rather the case against it.
>>So, let me get this straight… the faith of our economy and
>>politics rest in a few dozen old trees somewhere that grew
>>in a limited little spot on the earth?
And the fate of a few trillion dollars of our money, too.
.
>>Nature a scientific journal?
>>It has become an activist political mouthpiece.
Just like New Scientist and the BBC.
.
I have a small theory as to why. After the War (WWII) we had a great mass of journos, like Robert Capper et all, who were front-line soldier-jounos and real meat-eating men (and women too). They took over the BBC and media for a whole generation – spawning the likes of the peerless Raymond Baxter with good, honest scientific reporting.
But the media is generally a liberal art, and later candidates and employees were all from the liberal sector, if you see what I mean. So perhaps we should not be too surprised that liberal issues and agendas are now being pushed to the fore. A few more meat-eating graduates need to swallow some pride and apply the grease-paint.
.
Tom P 1:08:11
So what do Briffa’s cherry picked trees show us the temperature was in the 20 Century and what do the nearby thermometers show?
Answer, the cherry, actually larch, orchard has a hockey stick and the instrumental record does not. Big problem. Maybe those better randomized young trees are better treemometers. More likely, it’s the randomization, which is the critical flaw with Briffa.
Do you get it? Non-randomized is cherry-picked.
=================================
Ah, Keith Briffa has weighed in, see the link at the end of the Register thread at CA. I note that he is ambiguous about whether or not this series was compared to temperature to pick it. He claims not to be doing so now.
============================================
Tom-P said:
Hence the Schweingruber series does not contain the long-lived trees necessary to discern a centennial or multicentennial variations. The Schweingruber series is therefore of very limited utility for a valid comparison with the much longer-lived trees of the CRU archive. Steve McIntyre’s sensitivity test between them is comparing a signal (CRU) to noise (Schweingruber).
Hence I am happy to withdraw my reconstruction based on the data from both series – the original Briffa plot stands unmodified. It is not the hockeystick of Briffa’s Yamal reconstruction that has collapsed, but rather the case against it.
…..Man, you’re swinging at the logic pinata, but only hitting the tree. This argument is is so bad, even I can see the gaping holes. Just because one paper is bad (in your opinion) doesn’t automatically make the other good. I ‘ll let someone else take over. I have to go to work.
BTW, On Briffa, I think you should check Steve’s latest post. It appears “The Blade of Briffa” is created by ONE tree!
Cross-posted from CA:
Steve McIntyre:
“However, I disagree that the trees in the CRU archive are “much longer-lived”, other than the trees selected for the modern comparison.”
But the modern comparison was the subject of your original sensitivity analysis that was supposed to have broken the Yamal hockeystick!
All you have done is inject noise into the Biffra/H&S series by adding in much shorter lived trees. This also explains why the Schweingruber series did not well correlate with the instrumental temperature.
Tom P (07:35:54) :
This is a false interpretation of the standardizaton methods in tree rings. The net result of this reconstruction is a mean, nothing more. An average of the available data. There is no recentering, no RegEM no fancy PCA just an average of the ring widths as standardized by the same exponential function for every tree ring width.
Pretending that you have killed Steve’s work again (a third time) and again by weak arm waiving means nothing.
re: Tom P (01:08:11)
“Steve McIntyre’s sensitivity test between them is comparing a signal (CRU) to noise (Schweingruber).”
And this is self-evident? Instead of arm waving, perhaps a little demonstration is in order before you pop the champagne corks.
woodNfish (12:24:30) :
Richard (23:08:47) : “until shot down by the “Texas sharpshooters” on CA”
“Richard, if you understand what the Texas Sharpshooter fallacy is about, you will also understand that it is not a compliment to Steve McIntyre and CA even though you meant it that way.”
I do understand what the Texas Sharpshooter fallacy is all about. And by Texas Sharpshooters I meant the ones who exposed this fallacy to “shoot down” Tom P, not that they used the fallacy themselves. It was Tom P who used it. “Sharpshooters” and “shooting down” was used as the pun, after all sharpshooters are the guys who shoot down people.
This is what I posted at Real Climate
Richard says:
Your comment is awaiting moderation.
1 October 2009 at 6:44 PM
From what I understand of the Yamal chronology story, Briffa used 12 tree rings for the reconstruction of the 19th and 20th centuries – more for the 19th century and even less for the 20th.
This reconstruction shows a hockey-stick graph, where the current warm period is far warmer than any in the past 2,000 years. When all of Prof Briffa’s and the Schweingruber data is used, the graph is quite different. In this graph, whereas the current warm period shows up, the medieval warm period, for this complete data set, shows as warmer than the current warm period.
Now it was questioned why Prof Briffa used only 12 trees for the modern reconstruction and it was argued that these trees best agreed with modern instrumental records. And the criticism to this argument was that this amounted to cherry-picking and “sharp-shooting” – picking the data to get the result you wanted from the data, rather than letting the data give you the results.
To me this makes sense. From my high school science I was told that in a scientific experiment, you must record the data as it comes. You must in now way manipulate this data to predict its outcome, even though this outcome maybe expected.
This criticism appears to carry more weight when it appears that just one tree out of those 12 is responsible for most of the big warming of the current warm period.
What are your comments on this?
There have been 12 comments since then which have been published but mine is still “awaiting moderation”. Comments which include backslapping each other and tearing down “deniers” in somewhat unmoderated language.
When posed with real questions on the Yamal affair they appear to be perplexed on how to handle it.
And it has now been moderated out. Leaving the field to others with comments like:
Dan L. says:
1 October 2009 at 7:57 PM
>dhogaza: I’m glad that RC is hitting back.
Indeed.
McI is a coy, sneaky b… uh, fellow. He is cunning enough to avoid directly exposing his nitpicking to peer reviewed publication, relying instead on the usual suspects to shriek on his behalf. Congratulations to RC for knocking the pins from under the WUWTs of this world and their hockey stick obsessions.
Makes me laugh.