Bishop Hill Lonely old Mann
Nov 26, 2012 Climate: Mann A group of prominent paleoclimatologists has written a paper rebutting one of Michael Mann's recent contributions to the scientific literature. The new paper was announced on the ITRBD Forum by Rob Wilson. The list of authors of the new paper is very long. Almost looks like they are ganging up on him. ;-)
In February of this year, Mike Mann and colleagues published a paper in Nature Geoscience entitled, "Underestimation of volcanic cooling in tree-ring based reconstructions of hemispheric temperatures". Their main conclusion was that a tree-ring based Northern Hemisphere (NH) reconstruction of D'Arrigo et al. (2006) failed to corroborate volcanically forced cold years that were simulated in modelling results (e.g. 1258, 1816 etc). Their main hypothesis was that there was a temporary cessation of tree growth (i.e. missing rings for all trees) at some sites near the temperature limit for growth. This implies Dendrochronology's inability to detect missing rings results in an underestimation of reconstructed cold years when different regional chronologies are averaged to derive a large scale NH composite.
We scrutinized this study and wrote a response to Nature Geoscience. We are pleased to announce that our comment, along with a reply by Mann et al., was finally published on Nov. 25, 2012 (http://www.nature.com/ngeo/journal/vaop/ncurrent/index.html) -- 8 months after submission. Our comment focuses on several factors that challenge the Mann et al. (2012) hypothesis of missing tree rings. We highlight problems in Mann et al.'s implementation of the tree ring model used, a lack of consideration for uncertainty in the amplitude and spatial pattern of volcanic forcing and associated climate responses, and a lack of any empirical evidence for misdating of tree-ring chronologies.
We look forward to a continued discussion on this subject.
Kevin J. Anchukaitis, Petra Breitenmoser, Keith R. Briffa, Agata Buchwal, Ulf Büntgen, Edward R. Cook, Rosanne D. D'Arrigo, Jan Esper, Michael N. Evans, David Frank, Håkan Grudd, Björn Gunnarson, Malcolm K. Hughes, Alexander V. Kirdyanov, Christian Körner, Paul J. Krusic, Brian Luckman, Thomas M. Melvin, Matthew W. Salzer, Alexander V. Shashkin, Claudia Timmreck, Eugene A. Vaganov, and Rob J.S. Wilson
Reader Comments (173)
The list of authors simply represents those dendrochronologists who have utilised tree-rings to reconstruct past summer temperatures – plus a few extra individuals with specific skills w.r.t. tree-growth physiological processes and volcanic forcing. The numbers of collaborators bubbled upwards in the weeks after Mann’s initial paper as we discussed how we could robustly address Mann’s hypotheses. It was an incredibly stimulating period of collaboration where we bounced ideas and results around. Only a small amount of this interaction made the final cut due to space limitations. There are other longer papers in press/review that will expand on our NG piece.
Nov 27, 2012 at 3:29 PM | Craig Loehle
Nov 27, 2012 at 4:48 PM | Jonathan Jones
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Craig Loehle & Jonathan Jones,
The timing of the publicity about the paper widely authored by 23 scientists from 16 different institutions does give those attending the AGU meeting in SF next week a unique opportunity to focus on some of the problematical science authored by Mann and subsequently endorsed by the IPCC in its problematical coerced consensus.
If I were to attend the AGU meeting I would look for a rigorous related dialog.
John
John Whitman,
Agreed. There is not much point in debating this issue further at this stage as we're probably going to find out next week what is really going on!
Mosh,
Yes I condemn Scafetta for not sharing data and models, but he does not work for me. For my part, all my work is done in Mathematica, and if anyone wants to see anything, the entire analysis is in a nice neat package.
Rob pointed out that the large number of authors was to give a "robust" reply. I interpret that to mean "powerful" as in not just one or two guys but the entire field.
I do not think my comments about fear are misplaced wrt critiqueing Mann. Disregarding those who agree with him, there is in fact trepidation and a number of specific cases of people driven from the field or fired (editors) or attempted to be fired from their jobs.
I would be curious to see Rob's response to Jim Bouldin's new summary of the issues with tree ring analyses (and it applies equally to MXD unless it can be shown othewise). http://ecologicallyoriented.wordpress.com/author/jrbouldin/
willard.
evidence that the actual topic is the papers?
read all the comments.
You will see the typical silly types of comments you get at all blogs. Mann this, Mann that, Briffa this, Briffa that. ya for Steve Mc. This is ALWAYS in the preamble to conversations.
Then Rob Appears to try to get the conversation on track. You know discussing the papers rather than the politics and motivations around them.
Of course things careen around after that, but I consider the papers to be the ACTUAL topic.
Kinda why I point Rob at Gao's data. Opps, there is another piece of evidence for you.
Like all evidence its incomplete. You know, all theory is underdetermined by the evidence.
I should not have to explain that to you, but I'm charitable so I did.
Now, will people like yourself pop up and go mental and meta? ya sure. free electrons. go figure.
You've read enough blogs to know that there is always a Venting. Every body pulls out their favorite soap box and preaches. me too. Those facts, dont change what the actual conversation should be.
Especially since Rob showed up. My point is pretty simple and I dont know why you cannot exercise a little charity and see it. Oh, well, I'll put that down to something else.
Rob shows up. Folks should cherish that because he does not owe it to us to come and answer questions. Ask him about the science. Dont pester him for political proclamations about Mann or other nonsense. Leave the nonsense to people who have nothing better to do, like you and me.
"I'd be interested enough in Rob's reaction to Jim Bouldin's recent posts on dendroclimatology. "
Jim has done some really cool work,
"Steven Mosher
The one thing you've missed out in your comprehensive "why they didn't call out Mann" list is one of the commonest traits of any group:
They hate Steve because he was right."
I'm continually amused by the people who want to argue from the way Steve was treated to the truth of the science. not very skeptical.
Steve's a good friend. We often chat about the way he was treated. His response and my response has been the same since 2007. "what were they thinking?" We kick ideas around that try to explain it, but those discussions say nothing about the "truth" of the science. It's an interesting side show to try to figure out what "they" were thinking. Heck I don't even think they knew what they were thinking.
I don't object to side shows, but it shouldn't be mistaken for the main event
> Then Rob Appears to try to get the conversation on track. You know discussing the papers rather than the politics and motivations around them.
I believe that the main topic appeared in the thread long before Rob did.
The title provides a good hint:
> Lonely Old Mann.
This title introduces a topic that does not seem to be Rob's paper at all.
***
Due diligence still remains to be paid to the veracity of the claim about what Rob does here. So let's roll out the tape. Here's the first paragraph of Rob's first comment:
> Mann’s major flaw was to see something in his model which did not agree with “nature” and assumed that there must be something wrong with nature. Alas, if he had taken the trouble either (1) to speak to some of his dendrochronological colleagues or (2) look at some real tree-ring data to learn what “crossdating” is, he would have quickly realised that his hypothesis was wrong and would not have wasted a lot of time for many people.
So much the worse for the silence of the lambs.
Here's the second paragraph:
> In my opinion, not reading a paper just because Briffa is a co-author seems rather narrow minded. Feel free to froth at the mouth, but this just highlights how entrenched SOME of you are w.r.t. your ideas, opinions and biases.
This paragraph has little to do with Rob's paper.
Then comes the third and final paragraph:
> Simon Hopkinson – such a comment is really not very helpful – but **did, I guess, provide the impetus for me to write a quick comment.**
Emphasis added.
***
Seems that this impetus has been seen before:
> You are all missing the point. [...] Anyway, I am obviously wasting my breath. [...] anyway – enough with venturing into blog space
Rob does seem to entertain some kind of ambivalence toward climate blogland.
Perhaps I'm biased.
***
I'm quite sure that if we remove all the apophases from the institutions of climate blogland, we'd have a snark-free zone. One has to wonder what would remain of climate blogland. Some might have no reason to comment anymore. Some other might have less impetus to hit the tip jar. Lots of theories.
In any case, we certainly can see that the argument from topicality has no merit.
"You are right that there are many many reasons why people might not choose to get involved in pointing out that Mann's work is nonsense. However Craig Loehle is probably right about this current paper. You don't need 23 authors from 16 different institutes to point out obvious flaws in a paper unless something else is going on."
absent some independent evidence ( like a stolen mail from Rob that says 'we need everyone on board!)
I would say that the fact of 23 authors could be explained by other things. So, before speculating one might ask a few questions of the 23. And understand they dont owe you answers. I once did a patent where we had like 20 people on it. Every moron who sat in a meeting and questioned our design, every test subject, thought they had made a contribution. At some point the lawyers explained that I needed to shorten the list. man were people pissed. The other day somebody asked me why my name wasnt on a particular paper. Simple, in my mind suggesting ideas, criticizing ideas, and reviewing stuff is not the same as authorship. go figure. others think differently. So why 23? dunno. I do know that people who expect to find bad motives everywhere will in fact "find" them. That doesnt mean they arent there. Doesnt mean they are there.
Willard
I believe that the main topic appeared in the thread long before Rob did.
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By your logic then oliver manual would set the topic at Judith's every time. You think priority sets the actual topic? Of course priority in the thread can turn readers away from the actual topic, and make the main topic something else. Did you not take time to practice charity and ask me what I meant exactly by ACTUAL topic? No, you didnt practice charity. you realize that I selected "Actual" for a reason.
That would be opposed to the main topic ( the one that dominates ) or the intended topic ( one the author intended ). Funny that you of all people should miss that.
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The title provides a good hint:
> Lonely Old Mann.
This title introduces a topic that does not seem to be Rob's paper at all.
Yes, The title indicates the bishops intended topic. As you know, titles do not constrain the conversation. You might intend people to discuss the lonely old mann and people might decided to take things sideways from your intention. Like Rob did. The actual topic is determined by power. Rob actually has the power to change the topic from the intended topic to something that is actually interesting.
So much the worse for the silence of the lambs.
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Yes, and what exactly does that have to do with the argument over what the actual topic should be?
Perhaps I'm biased.
Agreed, perhaps you are. You seem utterly unable to treat any person who tries to discuss things with you with charity. You don't seem to seek a common understanding. You assume the worst in what they say. Your read them in a way that insures they dont make sense. Frankly, I'm shocked since you seem to have advocated the opposite. Was I wrong about that?
***
I'm quite sure that if we remove all the apophases from the institutions of climate blogland, we'd have a snark-free zone. One has to wonder what would remain of climate blogland. Some might have no reason to comment anymore. Some other might have less impetus to hit the tip jar. Lots of theories.
In any case, we certainly can see that the argument from topicality has no merit.
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I'm not sure I agree. I'm not at all clear what you intend with your thought experiment or what you are saying exactly. Perhaps, you could explain in simple language. I really am trying to understand what you mean. Perhaps we agree. Under one theory however, willard is never "on topic" can can never be "on topic"
He positions himself "above topic" by his own admission. He takes a meta position, which is a position about positions and position taking. So, he is always "off topic" by design. I like that about willard. But sometimes, you know, I prefer steak to cotton candy. Or as I said elsewhere, marginal. Understanding of course that I hold the margin of any text to be as interesting as the core.
see look. we discussed that a title cant control the text. we talked about priority. and about margins and tangents
Very interesting thread
But I'm not sure the significance of the response to Mann's paper is fully appreciated. There's a lot of amusement about an apparent 'split' in the warmist ranks. You almost get the impression from some posts that Briffa, Esper, even Malcolm Hughes(!) have suddenly decided that McIntyre & co were right all along.
I think probably not.
They've evidently decided - and there must have been a lot of preliminary discussion of this - to attack Mann on the basis of his understanding of dendrochronology. This is a step change, as previously the appearance of reconstructions with more variability than Mann's constituted an implicit critique of Mann's original, but they didn't require an explicit response. (Rob was quoted somewhere in the thread saying that he didn't want to comment on the Mann reconstruction since there were already several others)
That - what some of you call 'the silence of the lambs' - was partly down to McIntyre's strategy. To criticize Mann at that time would also be to support somebody who was not only systematically flooding climate scientists with vexatious FOI requests, but who was also perceived as a lukewarmer at best and - if not a denialist himself - was certainly happy to give blog space to all sorts of unusual perspectives. If you think, as climate scientist, that global warming is an existential threat, you're obviously reluctant to criticize somebody who, whatever you think of his science, makes it clear that he stands on the same side of the AGW question.
So why are they doing it now?
Simple. It's pretty obvious (certainly as far as the '23' are concerned) that events since 1999 have only served to confirm that AGW is occurring - and in many instances faster than the models predict. There's no need to worry about the politics - other people can do that, given that the substantive part of the science is settled - and the scientists can get down to making the science more robust, which is what it should all be about anyway.
Addendum: the last quote from my previous comment was taken from a comment thread at Steve's, referenced earlier by Jean S, I believe:
http://climateaudit.org/2008/11/30/criag-loehle-on-the-divergence-problem/#comment-169162
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The need to make this addendum provides us the impetus (our new theme) for this other quote, as some kind of bonus, Jean S's sideswipe hints at a discussion that started on **Myles Allen Calls for "Name and Shame"**, where we can read this short comment:
> If I had unlimited time, 9 lives say, I’d go ahead (maybe) and read the chapter you link to. But I don’t. I should have been working on my tree ring analysis paper today. Instead, I sacrificed time on that to read this post, then go track down and read parts of this Gergis et al paper, and then also the Neukom and Gergis (2012) paper which describes the larger set of proxy sites from which the former drew their sample. Then I spent some time reading some comments, and then some more time responding to Steve and others. If you can give me some concrete explanation of how that chapter relates specifically to the claims of why screening proxies, or my counter claims, or how and why stock portfolio analysis is a suitable analog for the tree ring issues raised, then I think you should try to do that.
http://climateaudit.org/2012/05/31/myles-allen-calls-for-ame-and-shame/#comment-335923
That Steve's names and shames has yet to be owned by its owner.
As readers can see, all this has mainly to do with science and statistics.
steven mosher:
I just returned to BH after a short break. How nice to see the 23 contributors on this thread! (It's only a rough estimate.) The return of some old names also screams out for explanation. I think there's a common thread - the limiting of Mann. However human activity is organised, or not, we (they) know the limiting of Mann is good, we want to ensure that it happens (one never knows what's enough - there's no proof afterwards), we want to celebrate it and, last but not least, nobody wants to be left out.
Dear Moshpit,
Please read the title of the post.
Please read the editorial comment of that post.
Please read the comments from the big names here.
Then ask yourself: what is the topic of the post?
Simples.
You have no case.
***
You have less than a case, in fact. If you continue to carry on with your tries to make me a topic of this comment thread, I might very well do the same with you. This means we could pay due diligence to your attempts to instill party discipline. So please, do continue to talk about topicality.
In other words, you're simply handing me the climateball to carry it in the endzone, which I will do with or without you on my back. This would not be the first time.
I thought you had a good memory, Mosh.
Mosh doesn't think 23 authors is significant. Unless it is a physics experiment where it takes lots of hands, or one combining lots of field work from all over, lots of authors is a headache. I was involved in a paper with 19 people. Why so many? We wanted to make a statement that it was more than someone's opinion. In it we argued that claims about biodiversity loss likely due to climate change were unfounded and wrong. We had some big names in the author list to lend weight.
BUT having that many people on a paper is a huge headache. The paper kept getting longer than the page limit after each round of editing. Writing styles differed. On the paper in question here the logic is likely similar--to show that a large and prominent group agree about the issue.
Nov 27, 2012 at 11:36 PM | Craig Loehle
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Craig Loehle,
I think the importance of the 23 scientists involved in the paper is reflected in the irrepressable sense of fun and joyful collaboration that Rob Wilson is expressing wrt the paper.
It is a convincing expression of importance.
John
Methinks the 23 just see that in this instance, Dr. Mann is wrong. There is no tearing of the brotherhood, just a robust scientific discussion. Period.
DeNihilist --I don't think Mann recognizes "robust scientific discussion", nor does "The Team". At the first sign of disagreement with The Cause, they (as in RealClimate site) goes into full attack mode. You are either friend or enemy. There is much significance in the 23 daring to take Mann on. In my case, I merely politely disagreed with Mann's approach in my non-treering paper and he devoted a section of his book to smearing me as part of the well-Oiled denialist conspiracy.
The superabundance of verbiage of blogs and in print could be reduced if authors set up their experiments correctly.
It used to be de rigeur to pose an hypothesis and to nominate a point at which the experiment would be stopped to either can it, or to rephrase the hypothesis in the light of what new was learned so far.
A past CEO used to caution us with "Knowing when to get into business is a third of the task. Knowing when to get out is the important two-thirds."
About 2 years ago I posted on CA that the evidence to date on using trees for thermometers was adequate to cause a pause and a rethink. I've not read much on the topic since, bit I'm sure I'd see a major breaktrough. I'm not being negative, I'd love to find a magic proxy that did all that we want to discover.
But, on all evidence to date, dendrothermometry has reached the pause point - except that they no longer seem part of the experimental design very often.
Principally, calibrations made in many places in the last 20 years, places where temperature has hardly changed, disbar late modern calibration; and before that period, the measured temperatures have been subjected to so much diverse adjustment that one does not know which time series to use for calibration, particularly pre-1950.
"To criticize Mann at that time would also be to support somebody who was not only systematically flooding climate scientists with vexatious FOI requests, but who was also perceived as a lukewarmer at best and - if not a denialist himself - was certainly happy to give blog space to all sorts of unusual perspectives."
What a spiteful, and untrue, little sentence. Steve McIntyre didn't flood anyone with FOIs, he wanted so see the raw dataand code used in published papers, which is, in my view what any scientist would expect to be asked to produce for replication of his/her papers. If he had to use FOI requests it was the because of the childish behaviour of the climate science community in refusing to publish the data and code for papers insturmental in the formulation of public policy.
I'll let the occasional contributors to CA deal with the snide "unusual perspectives", since I've been reading CA the only contributors I can recollect other than Steve Mc were fellow statisticians.
As for Mosh saying we can't speculate as to the motives until we have real evidence, I take a different view. Particularly because Mosh himself believes the evidence doesn't have to be decisive to prove the case!
We are allowed to speculate, it may prove nothing, but it does give people to extend their thinking on the issues at hand. The two big questions are:
1. Why 23 when as Einstein said "... it would take only one".
2. And why the previous silence on Mann's papers with equally egregious errors. In particular the use of "short centring" to weight the prinicipal components, the use of bristlecone pines as proxies, the use of upside down varves in a number of papers some, or all, of them co-authored by Malcom Hughes and all of them still extant.
Of course we can speculate, that's the thrill of it, but I doubt anyone here believes they'll hit the nail on the head without real evidence (or nearly real evidence if you don't need it to be conclusive).
As a human being, you are allowed to think what you like. As a scientist you are supposed to make some attempt at objectivity. It is the lack of objectivity among climate scientists, the refusal to consider other possibilities than "it's CO2 wot dunnit", the vitriol poured on anyone who has the temerity even to question let alone actually disagree that has created the degree of scepticism that there is around the subject.
Your assertion that "events since 1999 have only served to confirm that AGW is occurring - and in many instances faster than the models predict" illustrates the point. Increasingly we are seeing indications (and published papers) to the contrary. Evidently you disagree. There is a genuine difference of scientific opinion. Deal with it because the future of humanity may depend on it ...or it may not.
It is important that we know rather than rely on your "belief". Mann et al should be welcoming this paper (as well as others) as a contribution to better understanding of the science not denigrating it and launching personal attacks on the authors (which he doesn't appear to have done -- yet) because it challenges his "belief".
Scientists in any discipline ought to be their own severest critics. They sure as hell ain't in climate science,
Paul Butler, "You almost get the impression from some posts that Briffa, Esper, even Malcolm Hughes(!) have suddenly decided that McIntyre & co were right all along."
Read the climategate 2 emails. It's clear that Briffa, Bradley, Cook, Wilson, Wigley etc have known privately for years that M&M's criticisms of Mann were valid.
Paul Butler says
'If you think, as climate scientist, that global warming is an existential threat, you're obviously reluctant to criticize somebody who, whatever you think of his science, makes it clear that he stands on the same side of the AGW question.'
As Mike Jackson rightly points out this is not the way real science works. Mann should expect his colleagues to look critically at his work and to respond as a scientist to any such critiques. That is the way science progresses. As others have pointed out on this thread, there is a strong case that Mann's involvement in climate science has put it back a good many years and cost the public purse a lot of money. If you were truly interested in science you would be applauding form the rooftops the long overdue intervention of the magnificent 23 (used to be 7 but that's inflation for you).
As for your 'it's worse than we though't meme - save that for frightening the children. Or better still don't.
Dolphinhead - I do applaud the paper, sorry if I implied anything else (I just don't do it from the rooftops, it's slippy up there and in any case a bit of a cliche). There's no doubt that a robust discussion of soem of the methods and conclusions is necessary and healthy. I think I was just trying to understand why climate scientists had previously been reluctant to criticize Mann in public.
As for scientists not having a duty to speak out if their science tells them there is a potential threat - well, several Italian geologists and engineers found themselves senetenced to jail terms for failing to do just that ...
Paul Butler, if you are using the Italian scientists situation as an analogy, crying fire in a crowded theatre without any evidence is also a criminal offence. Talking of doom and gloom based on bad papers, model projections, manipulated data and crap statistics is also an offence then. Saying " this is what actual facts are as per empirical data, there's a lot we don't know and we need to study more " is the way true scientists would respond. At present not one single AGW supporting scientist has done it.
Paul Butler
You did more than that. You explained quite well that wrt to the matter och 'the cause' climate scientist weren't really scientists. You also, on a personal level, described how you view different opinions on a scientific matter, as question of personal animosity among groups, and who they associate with (or just are claimed to be assiciated to). You even demonstrated that you believe (?) that the term 'denialist' has anything to do with said scientific questions.
I think you were quite clear about what you meant. And I'm afraid that you definitely aren't alon with such and similar sentiments. Not even among those who call them selves 'climate scientists'
> By your logic then oliver manual would set the topic at Judith's every time. You think priority sets the actual topic?
That's not the logic I had in mind, Moshpit. Please recall what I said: look at the post title, the editorial content of the post, and the main contributions to this thread. I don't recall Oliver fitting this description.
Either you're being silly, or abusing parsomatics, or both.
Besides, my claim is not a logical one. Here's an example of a logical claim:
First, look at this comment from Jonathan Jones:
(1) Craig Loehle is probably right about this current paper. You don't need 23 authors from 16 different institutes to point out obvious flaws in a paper unless something else is going on.
I believe that Jones is referring to this comment:
(2) People have asked why the dendro/paleo community have not openly disputed Mann before. The reason is simple, he has had enormous power, enough power to destroy a scientist's career. It only takes rumor or a phone call or two to cut off funding in some fields or to deny tenure (which cames very late in life these days). Mann was tied up centrally with IPCC and has had powerful friends. What was different this time? Mann disputed the reliability of cross-dating and the ability of field people AND the biology by asserting that huge regions would all have missing rings--a nonsensical statement to anyone who knows how trees grow. Why so many authors? I speculate that it had to do with safety in numbers. He can't sue all of them.
How (2) is reduced to (1) shows a nice example of apophasis. But suppose you accept (1): something else's going on. (This claim is quite trivial, on the face of it: no one doubts that something else than the paper has caused the paper.) How do you get from (1) to (2)? It would take a big step in quantum logic to get from "something's happening" to "Mann's an evil mastermind", paraphrasing of course.
Now, suppose I were to claim that (1) can't be considered as equivalent to (2), on the proof that (2) does not follow from (1). THAT would be a logical claim. See the difference?
Finally, I hope you don't want to compare Loehle's and Jones' comments to Oliver Manuel. That would be quite abusive and also quite childish, don't you think?
We never have the conversation we should have. Telling people they should not be having the conversation they're willing to have might not provide the best impetus to have the conversation we should.
From my perspective, I feel privileged when I can witness a professor of a formal science entertaining lots of theories with a jack of all trades who published in about half of the scientific journals of the planet (and who knows when Craig will stop extending the field of his expertise!) in a public forum such as our beloved Bishop's. I just wish they could continue.
Craig, I see this as a discussion on the one Mann paper only. I do not see anywhere that the 23 are repudiating any of his earlier works. As for your experience with Mann, I cannot comment.
About 15 years ago I was trying to implement a complex geophysical/rock physics problem from a published paper in a peer reviewed geophysics journal. The lead author was world renowned in the field. I was relatively inexperienced (about 13 years) and the problem was slightly out of my usual technical field. The paper included a full methodological description and used a well known, published dataset as the test set, with input parameters and tabulated results.
I couldn't reproduce the results. I spent weeks trying to implement it and I couldn't work out what I had done wrong. One equation made no sense to me so and I thought I had found an error. As I had met the author once or twice at conferences, I decided to email them for help. The reply came back within the day, apologising that I had had such a problem and congratulating me for the spotting the error in the paper, as published. Unfortunately I was the second person to spot it and the the lead author had already submitted a corrigendum to the journal, correcting the error and thanking the other party for bringing it to their attention.
That is how science is supposed to work. It shouldn't take a list of 23 authors to make the point unless you think the recipient of the correction simply is not going to listen. A true giant in a field should be able to recognise when they have made a mistake and should be big enough to accept the correction publicly, and even thank the people who brought it to their attention.
Like Mann should have done with Mann et al 1998 and 1999. And Steig et al 2009. In my opinion those papers (and there are others) should be withdrawn from the literature.
The whole can of worms surrounding not just this paper (and Rob et al's response), but the field more generally, is a very troubling situation for some us, I can state that with good confidence. Regardless of all these personal animus issues (and believe me, I have my own stories on that), we need to try to stick clearly to issues surrounding the validity of the science, to the limits of our abilities.
Paul Butler
I want scientists to act as scientists. Nothing more nothing less. They should make it very clear when they switch from scientist to private citizen when offering a view. Clearly their professional calling will inform that view but it does not give it any more legitimacy than the personal views of an oil company director or a fishmonger. When an individual crosses the line between science and advocacy, science is always the loser. Are these guys not clever enough to see that?
And as an aside it always amuses me when you see some representative of Greenpeace or one of the other unelected 'voices of the people' telling us 'I'm a scientist' and then going on to behave like an activist. Do these people think we are daft? Well as a matter of fact, yes, they do which is why they have zero credibility.
Lets all take a leaf from Jim Bouldin's book and require scientists to stick to the science. We can safely leave the bullish*tting in the hands of the polis and the churnos.
Jim Bouldin:
It's good to be troubled by it. I believe you mean that. It's what you get for your troubles when you seek to put the situation right that tends to sort out the men from the boys.
Jim Bouldin and Mosh: the urging to "stick to the science" is laudable, but from many perspectives what is the key question is why and how did the scientific process break down in this field? It is no doubt partly because experiments can not be done (can't grow some trees in the lab for 1000 years and see if they match theory). But the sociology of the hysteria about the issue, the institutional power of the IPCC, the existence of attack dogs (RealClimate) that intimidate dissenters, and individuals like Mann who have power and the ear of the press are all equally valid items for study and discussion. Such discussion does lend itself to speculation and can be data-poor, but it is what it is. It is of course true that other areas of science get off track (many areas of medicine for example, and don't get me started on psychology), but those who come here are interested in this field. So, yes, the topic of missing rings (or not) is interesting, but I think the process is not irrelevant.
So the notion that there is a cabal of scientists promoting AGW, in lockstep, has been disproven? The scientific debate really is robust after all?
Craig at x:35:
I'm not opposed to evaluating the "meta" issues of any science field--those are certainly legitimate subjects. But thoroughly clarifying the science issues must come first IMO, or you create or compound problems. My main point though is to keep the personal animus from spiraling out of control, which it can easily do.
The degree of dissent within RealClimate might well surprise you, though I can certainly see why you would have the view you do.
As for the roles of theory and experimentation, I think there is some (limited) role for experimentation on real trees. But I would argue that there is a very big potential role for simulation and model experimentation to evaluate the limits of various possible analytical techniques, much more than has occurred to date.
what makes you think that, Mughal? You should pay more attention to the discussion.
> [W]hat makes you think that [the scientific debate really is robust after all]?
I'm not sure about Mughal, but for now, and notwithstanding the impetus most participants have in this discussion, we have:
- Rob's comments to date on this thread;
- Craig's and Jonathan's "something's happening";
- the evidence base for Craig's and Jonathan's remark;
- Jim's last comment.
Was that a real question, diogenes, or were you just cynically jerking around?
Willard
I've read this entire thread with a great deal of interest, I do not normally suffer from comprehension issues but I have completely failed to understand what relevance anything you have contributed to this discussion has to a critique of a significant conclusion from a Mann paper authored by numerous scientists with long and distinguished publication histories in the field.
I'm not interested in your personal views of the motivation behind the thread, those who join the discussion and those who haven't, anymore than the cant of extremists on either side of the climate debate.
Having waded through the obscure and irrelevant, I finally find some text that brings clarity
Snark³, to paraphrase Dr Muller, I now have another name on the list of bloggers who I wont read anymore
Gras,
Thank you for your comment.
I'm not sure you read all the comments. Could you post back the first comment I made here on the thread?
It might be tough to follow an exchange of moves when some are being erased.
Many thanks!
watches willard jerk...i know where I am
I agree. I cannot figure out willard's contribution here, though that is difficult to do even in the best of times.
Jim Bouldin,
Thanks for commenting here, and for three exceptionally interesting posts at your own blog.
Nov 28, 2012 at 4:35 PM | Craig Loehle
"It is no doubt partly because experiments can not be done (can't grow some trees in the lab for 1000 years and see if they match theory)"
Nov 28, 2012 at 6:44 PM | Jim Bouldin
"I think there is some (limited) role for experimentation on real trees. But I would argue that there is a very big potential role for simulation and model experimentation..."
Surely experiments to compare tree ring width (or whatever) and temperature in a lab are easy. We can grow trees for a few years in a lab. And if you think that is too hard then at the very least it should be trivial to get a recent (good) temperature record in an area where you think trees would respond well to temperature, predict the tree ring width (or whatever again) from the recorded temps, chop them down or core them and see if you were correct. This would be the defining paper on whether it would be worth extending the method to 1000 year old trees say.
From my experience in the climate field (as a modeller) I definitely think there is far too much modelling/maths in the climate field and not enough empirical experiments. Prior to climate modelling I had done a few years of Geology which is obviously more field based and the main basis for my high scepticism when the original Mann study was revealed so publically.
Of course growing trees in a lab, while interesting if you want to understand growing patterns under. Controlled conditions, says very little about periods in which few (if any) of the inputs are unknown. That is, and always will be, the fundamental problem of treemometry. Divergence merely serves as proof that past behavior is (currently) unknowable.
This is a problem even before arguing the statistics.
Mark
I was struck last night reading a great story of academic rivalry and respect, When academics seek truth and not just fame, by Professor Thomas Sowell, published two days ago. Another not uncontroversial area, going back to the 1960s. It can be done.
Mark T,
"Divergence merely serves as proof that past behavior is (currently) unknowable."
Trees are made responsible for the divergence without any evidence. Divergence is a general problem affecting the majority of comparisons thermometer - proxies. There is little doubt that this is actually stations temperature that diverge from regional temperatures: http://img38.imageshack.us/img38/1905/atsas.png
Nov 29, 2012 at 1:24 AM | Mark T
"This is a problem even before arguing the statistics."
This would be my point. At least under controlled conditions you might show the key effects of things like sun and water availability. I'm confident in saying it is a useless pursuit in the first place without seriously studying it in the first place, but what do I know....
Richard Drake (6:05 AM) -
Thanks for the link to the Thomas Sowell article. Informative and interesting, especially the contrast drawn between investigative and dogmatic approaches. Perhaps we're seeing an echo of that here.
HaroldW: It was that optimistic thought that made me post the link. Note that Sowell is not so unrealistic about human nature as to suggest in his title that academics should not seek fame. I sense that the Mann at the centre of the criticism here has a big question to face: is fame enough? Even if someone makes a wrong choice in that regard it would be possible for the discipline, eventually, to sideline him. Thank you for your feedback.
Speaking of statistics, here's what a (blog) discussion could be like:
http://andrewgelman.com/2012/11/16808/
Academics never needed public castigation to sideline anyone.
In the end, only (relevant) citation matters.