We’ve long discussed the bias imparted by ex post selection of data depending on whether it went up in the 20th century. Likening such after-the-fact selection to a drug study carried out only on survivors.
The Jacoby and d’Arrigo 1989 network was a classic example: the original article reported that they had sampled 36 northern treeline sites, from which they selected 10 with the “best record…of temperature-influenced tree growth”, to which they added a chronology of Gaspe cedars that was far south of the northern treeline at low altitudes.
In 2004 and 2005, I made a determined effort (link) to obtain the measurement data for the 26 sites that weren’t included in the final calculation. Jacoby refused. I tried over and over to get this data, but was never successful.
Gordon Jacoby died in October 2014. In June 2014, a few months prior to his death, the Lamont Doherty Earth Observatory unit of Columbia University (Jacoby’s employer) archived a large collection of tree ring data collected by Jacoby and associates (link). By then, it was 25 years since publication of Jacoby and D’Arrigo 1989 and 8 years since publication of D’Arrigo et al 2006.
By then, the paleoclimate community had “moved on” to the seeming novelties of PAGES2K. A few Jacoby and d’Arrigo series re-appeared in PAGES2K. I wrote a couple of articles on these new Jacoby and d’Arrigo avatars: on their Central Northwest Territories (Canada) series in January 2016 here; and on their Gulf of Alaska series in February 2016 here and here. But the articles attracted little interest. Jacoby and D’Arrigo had successfully stonewalled availability of data until no one was interested any more. Not even me.
However, while recently refreshing myself on ancient MBH98 issues, I discovered something interesting: buried in the dozens of measurement data sets in the belated 2014 archive was one of the datasets that Jacoby had withheld back in 2004. (Thus far, I’ve only found one, but there may be others.) It was a northwest Alaska dataset collected in 1979 – . What did the withheld data show? Despite the passage of time, I was interested.
Long-time readers will undoubtedly recall Jacoby’s classic data refusal:
We strive to develop and use the best data possible. The criteria are good common low and high-frequency variation, absence of evidence of disturbance (either observed at the site or in the data), and correspondence or correlation with local or regional temperature. If a chronology does not satisfy these criteria, we do not use it. The quality can be evaluated at various steps in the development process. As we are mission oriented, we do not waste time on further analyses if it is apparent that the resulting chronology would be of inferior quality.
If we get a good climatic story from a chronology, we write a paper using it. That is our funded mission. It does not make sense to expend efforts on marginal or poor data and it is a waste of funding agency and taxpayer dollars. The rejected data are set aside and not archived.
As we progress through the years from one computer medium to another, the unused data may be neglected. Some [researchers] feel that if you gather enough data and n approaches infinity, all noise will cancel out and a true signal will come through. That is not true. I maintain that one should not add data without signal. It only increases error bars and obscures signal.
As an ex- marine I refer to the concept of a few good men.
A lesser amount of good data is better without a copious amount of poor data stirred in. Those who feel that somewhere we have the dead sea scrolls or an apocrypha of good dendroclimatic data that they can discover are doomed to disappointment. There is none. Fifteen years is not a delay. It is a time for poorer quality data to be neglected and not archived. Fortunately our improved skills and experience have brought us to a better recent record than the 10 out of 36. I firmly believe we serve funding agencies and taxpayers better by concentrating on analyses and archiving of good data rather than preservation of poor data.
They may also recall Rosanne D’Arrigo’s remarkable 2006 presentation to a dumbfounded NAS Panel, to whom she explained that you had to pick cherries if you want to make cherry pie, as I reported at the time (link):
D’Arrigo put up a slide about “cherry picking” and then she explained to the panel that that’s what you have to do if you want to make cherry pie. The panel may have been already reeling from the back-pedalling by Alley and Schrag, but I suspect that their jaws had to be re-lifted after this. Hey, it’s old news at climateaudit, but the panel is not so wise in the ways of the Hockey Team. D’Arrigo did not mention to the panel that she, like Mann, was not a statistician, but I think that they already guessed.
D’Arrigo et al (2006) was relied upon by both NAS Panel and IPCC AR4, but, once again, D’Arrigo refused to provide measurement data – even when politely asked by Gerry North, chair of the NAS Panel.
Sukak Peak (ak106)
The measurement data for ak106.rwl ( link), Sukak Peak, Alaska, showed that it had been sampled in 1979. It was at the same latitude (67-68N) in NW Alaska as the three Alaska sites used in Jacoby and D’Arrigo 1989 (Four Twelve, Arrigetch, Sheenjek) and was located about halfway between Arrigetch (151W) and Sheenjek (144W).
It seems virtually certain that this was one of the “other 26” sites that Jacoby had sampled prior to Jacoby and D’Arrigo 1989, but had excluded from the study and then vehemently refused.
Here is a chronology for Sukak Peak (ak106) using Andy Bunn’s dplR (ModNegExp option to emulate Jacoby methodology), produced using Bunn’s dplR plot function: chronology in solid line (left axis scale), core counts in light grey (right axis scale):
First, the chronology (dark line) had elevated values in the AD1100s; its 20th century values were unexceptional and declined through the 20th century, with closing values indistinguishable from long-term average. It definitely doesn’t tell the “climatic story” that Jacoby was trying to tell.
Second, and this is a surprise (or maybe not), the core counts – shown in solid light grey in the above graphic – show that Sukak Peak had 10 cores by AD1311 and was at 5 cores by AD1104. In contrast, the entire Jacoby network incorporated into MBH98 had only one core (from Gaspe) prior to AD1428 and none prior to AD1404,In other words, although this had been withheld by Jacoby, replication at this site was better than at any other Jacoby and D’Arrigo site used in MBH98. It was not “lower quality” in any objective sense.
Although Sukak Peak data was still unarchived and unpublished in 2006, it was used in the D’Arrigo et al 2006 NW Alaska Composite dataset, the chronology of which reported high late 20th century values – the opposite to what is displayed in this component. The NWNA Alaska Composite also included subsets of Four Twelve, Arrigetch, Sheenjek (none of which show high late 20th century values) and a later dataset from Dalton Highway which I’m presently unfamiliar with. I will take a look at this dataset in a follow up post.
In closing, I had long presumed that data for the “other 26” Jacoby and D’Arrigo northern treeline sites had disappeared forever. But it turns out that data for one of the sites was archived in 2014 – 35 years after collection in 1979, 25 years after publication of Jacoby and D’Arrigo 1989 and a mere 16 years after publication of MBH98.
Plus another 9 years before anyone noticed that Jacoby’s death-bed archive contained one of the long withheld “other 26” sites. A pleasant surprise nonetheless. But definitely not a surprise to discover that the withheld data did not have a hockey stick shape.
Climate Audit 
29 Comments
Thanks for your perseverance and recent entries at climate audit Steve. Even these seemingly archaic pieces add important and incremental context that I hope in future decades will help people piece together what went so wrong with climate science.
0. This was a much more readable article than the norm. Kudos. Minor critical comments, follow.
1. Please don’t start an article with a parenthetical digression. “Entirely separate from idiosyncratic errors like Mannian principal components…”. For the same reason commenters don’t need to argue every climate article in every blog post, you don’t need to digress either. Also, that’s a very important spot in the article, not a good place for an off-theme comment. But, FWIW, the overall article is nicely focused.
2. Unless you have solid documentary forensic evidence, I would not use say “definitely” or “without question” in para 11. It’s probably very likely. Sure. I buy that. But unless you have the list of 26 and this is one of them…or some other such logical proof, which you share in the article, I wouldn’t use your wording. It’s miscommunication to the general reader to use “definitely” to mean “I’d bet my ass”. You don’t have Euclidean proof here. It won’t water your article down to use a qualifier. Maybe for the hoi polloi, it’s irrelevant since they want to vent. But for the careful reader (of either persuasion), it’s an article-reading speed bump to overstate something. The careful reader will expect you to show the article to show proof of “definite” and it’s confusing to him when that then doesn’t follow.
2.5. Also, the second sentence of para 11 could just be excised. It’s not saying anything the first sentence didn’t. It has that too strong “without question”. And it seems to be missing something like “to archive” at the end.
3. The first para after the chronology figure was confusing. I looked back and forth a couple times to see how number of cores was shown in the figure (“First…”). But…it’s not. This is stylistic, but seriously, it was confusing. Probably better if the second para after the figure came before. It’s just another speed bump when you show a picture and then the immediate following discussion is of something not in the picture. (Without even the “not shown” caveat.)
thanks for these comments. All very constructive and helpful. I’ve edited text accordingly and it improves the article.
are you the commenter formerly known as TCO? Nice to hear from you after all these years.
Tanquam ex ungue leonem, Nigel. 😉
Thanks, Steve, for yet another important piece of the jigsaw and the enjoyably understated commentary you provide. I don’t know how you maintain such rhetorical restraint in the face of this persistently outrageous behaviour.
Imagine that! Thanks for your perseverance and for posting! Would be interesting to find a few more of these.
I am thankful that I joined late enough in your adventure (and young enough) to see you find a smoking gun in the MBH98/99 case. Does it matter the data is marked 1979 or is one of “the 26”? How do we know there are not any number of data sets that were discarded? The big jump at 1100 followed by a shaft is almost a reverse hockey stick. If these kinds of plots are due to local circumstances or are completely spurious then mining 100 sites would certainly provide a dozen with the jump in the 20th century preceded by a shaft. If this is true and the whole scientific field has covered this up this in not just an indictment of Mann, it’s much bigger.
there aren’t many cores in 11th century. I don’t encourage people to try to deduce very much, if anything, from tree ring chronologies. My main point in this post was to document Jacoby and d’Arrigo cherry picking.
You wrote, ” My main point in this post was to document Jacoby and d’Arrigo cherry picking.”
Is that a fair description of your main point? Let’s guess that you’re right that this 1 proxy is one of the 26. Have you seen the other 25? How do you know they don’t show hockey sticks? I think there are a lot of assumptions in this post: first, that you guessed right about this proxy; second, that these 26 proxies didn’t show hockey sticks on the basis of this one and that’s why they were excluded; and third, that the authors didn’t have good reason to not use this proxy should it have been in the 26.
The fact is you can’t say much about these 26 proxies on the basis of 1 proxy that may or may not have been among the 26.
First of all, there was no valid reason for withholding the measurement data for the 26 sites that were sampled and considered and not used. All of the data should have been archived. Further, the journal (Climatic Change) and funding agency (NSF) should have required Jacoby to archive the data. There was every reason to believe that the data was cherry picked. The data discussed in this article supports the view that the data was cherry picked.
You wrote, “There was every reason to believe that the data was cherry picked.”
But you didn’t supply one. Jacoby and d’Arrigo chose 10 out of 36 sites “judged to provide the best record in time and space of temperature-influenced tree growth for this region of North America.” The paper goes into details explaining why some sites may not yield a clear temperature signal, such as sites with “moisture stress or ecological stresses.” You found 1 site that may or may not be one of the 26 excluded sites, but you know nothing about the other 25. You have no idea if any of those show hockey sticks, and you don’t know that this site was excluded because it didn’t. You assumed that motive for excluding this site and then assumed the other 25 were excluded for similar reasons. That’s the only way to justify your claim that they were “cherry picking” the 10 sites they used. You would have to have knowledge of the 26 they didn’t use to make that claim.
Whether they should or shouldn’t have archived data that didn’t sufficiently preserve a clear temperature signal is besides the point. The point is you concluded that the 10 sites were cherry picked on the basis of next to no evidence. You know next to nothing about the 26 sites that were excluded, save 1 site that may or may not have been among the 26.
Uh, in her presentation to NAS Panel in 2006, Jacoby coauthor Rosanne D’Arrigo’s PPT included a slide entitled “Cherry Picking”. Here’s my contemporary report:
They aren’t even subtle about it.
The Climategate emails contain some amusing reaction to D’Arrigo’s admission.
Not to beat a dead horse here, but that doesn’t contain evidence that you know anything about the 26 excluded sites or why each was excluded. Even if we were to grant your speculation that this site was one of the 26, you didn’t evaluate whether it contained evidence of “moisture stress or ecological stresses” that would obscure the temperature signal. You simply plotted the ring width index at the site. In other words, you have no evidence of cherry picking. You assumed cherry picking and you’re imposing that assumption on the one site you have access to. Then you assumed that the other sites were excluded for similar reasons.
Simmons,
You haven’t been following this for very long, have you.
Every time, I don’t think there’s been an exception, that these non-selected proxies is unveiled, in whichever study, cherry-picking is blatantly evident.
To my knowledge, no one yet has been able to actually pick out a “temperature signal” from tree rings. Just because some of them sort of follow temperature for a very short time during the “calibration period” (but then mysteriously stop following it), doesn’t mean there ever really was a “temperature signal”. Then there’s the question of which temperature signal? Global? There’s no such thing. So unless you know the temperature history of that particular spot, you can’t say there is any temperature signal at all in tree rings. Of course, if you had that, you wouldn’t need tree rings…
There are a great many of these studies where maybe one or two proxies show something remotely resembling a hockey stick, but none of the others do. Yet the final result shows a remarkable hockey stick (Briffa’s Yamal study comes to mind, one tree to rule them all). How does that work exactly? Well, with Mann, we know. It’s from dubious statistics, and grossly overweighting of one proxy that tells the “right” story.
Jeff Alberts: “To my knowledge, no one yet has been able to actually pick out a “temperature signal” from tree rings.”
Says more about your knowledge than tree rings. Too much McIntyre, not enough Esper.
South American tree ring proxies provide an excellent example of both ex post picking and inconsistency. Out of a very large population of tree ring chronologies, only a few are ex post selected into PAGES2K. See here re 2017
https://climateaudit.org/2018/10/07/pages2k-2017-south-america-revisited/. Even worse in 2019 PAGES.
Pat Cassen: “Says more about your knowledge than tree rings. Too much McIntyre, not enough Esper.”
Do enlighten me.
I didn’t mean to imply anything about the 11th century. My point is that this reverse hockey stick is likely typical random shape found in tree ring proxy plots at different sites. This is point that you and many have made that the MBH hockey stick can be created by just cherry picking the sites that have 20th century blades, or just rewarding such sites with overweighting. The divergence problem of the best (highest weighted) proxies failing after 1960 or some point thus needed “Mike’s Nature trick” to bodge.
Here is your 2006 posted quote of d’Arrigo on why the 26 needed to be discarded. She basically says it the sites data does not say what we want it to the data must be wrong.
Too bad that it takes so much time for the truth to emerge.
This coupled with 100 years pseudo-predictions makes the ‘scientists’ long dead before they can be held accountable.
any way to get all this is pdf form ?
Unfortunate (but not the end of the World, and not your fault at all) that some fans are overplaying this:
https://nitter.net/KingMakerFT/status/1734671453709099190#m
“further proof of fraud”
Yes, the “F-word” that we all avoid. 😉
” critical tree line data”
It’s not critical, not some smoking gun. Heck it’s (probably) 1 of 26 missing sites. And the result (non remarkable behavior) is totally expected. “Not a surprise” (last sentence of post). And really just hashing an old issue (proxy selection debate, cherry pie picking, etc.) And while I’m much more sympathetic to critic side…think there’s a big danger with trees of low degrees of freedom when you select the 20th century temp rise series (and then get random noise cancelling in the “shaft” of the stick), it is something that is at least lined up with a rationale by the “Team”. If you had very good proxies (say coral, with it’s wiggle matching), you could see the rationale for using that and excluding trees (probably all of them). But warmists are making the argument that they know some trees are non-responsive (e.g. non treeline). The issue/debate comes when we get proxy selection after seeing the results, versus before. But…bottom line is it’s an established debate, even if I agree with our side more. Not some new smoking gun.
A very nice find! It’s simply shocking and sad to see how these pioneers in climate research performed their research.
Two questions:
1) Do you agree or not that Pages2k overcame the deficiencies of these original studies?
2) Were these tree ring vs temperature studies misguided all along?
Thanks for your work, your passion and your perseverance. You may have heard that a few months ago the entire paradigm of Alzheimer’s research collapsed when it turned out that one of the original studies was fraudulent….
PAGES2K is a mess. I’ve discussed issues with it from time to time, but biggest issue yet was discovered by Soderqvist earlier this year. Discussed at X e.g.
https://twitter.com/ClimateAudit/status/1653034589781123072. PAGES2K introduced a flawed tree ring algorithm that generated artifact upspikes at the end of the series.
alright, great. are these tree ring studies even useful or are there just too many uncertainties and influences (e.g. rainfall) to reconstruct temperature chronology at all?
“PAGES2K introduced a flawed tree ring algorithm that generated artifact upspikes at the end of the series.”
Was it really flawed? Or did it do what it was supposed to?
“The Science”, eh?
I used to cut trees down for a living – until I found out that I could make a much better living by planting them.
When I first heard that people – “scientists” no less – used trees as thermometers by measuring the thickness of their growth rings…
It depends on where you take the core. Compare a “chronology” taken from the left side of this tree with one taken from the top.
Or am I missing the point?
https://images.app.goo.gl/FbWsWaQk6Ai246Wi6
Steve,
Those of us like Pat Frank and me who have conducted analytical chemistry and those of us like you and me who have worked in mineral resources have different views on how science should be conducted, different to those who screen out data before deeper study, who ignore effects like the divergence problem, who weight measurements by their subjective criteria, who cherry pick data, who adjust instrumental measurements when there is no reported malfunction, etc etc.
I am not surprised by the inability of climate research to be taken seriously by those with records of success in other measurement and science sectors. Can you imagine the lack of success in mineral exploration geochemistry if measurements were adjusted subjectively as in “We should drill here despite our assays getting lower and lower as we do more, because my belief is that there are unexplained divergent factors making this prospect look worse than it is.” Geoff S
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[…] Gordon Jacoby and tried unsuccessfully to get his hands on it. Jacoby died in 2015 and McIntyre just stumbled on an online archive where Jacoby had quietly posted the secret record instead of prudently deleting […]
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