UPDATE3: professor Rob Wilson leaves some scathing comments about the Mann paper. See below.
UPDATE2: There’s been some additional discussion on the dendro listserver, and it seems quite clear now that the scientists in the dendrochronology field don’t think much of Dr. Mann’s effort – and it appears there is a rift now between former co-authors. See the must read below. I’ll make this a sticky for about a day, and new posts will appear below this one. – Anthony
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People send me stuff.
In case you don’t know, ITRDBFOR is an electronic forum (a listserver) subscribed to by most of the world’s dendrochronologists. What is most interesting is that Hughes and Briffa are co-authors of the response to Mann.
—– Original Message —–
From: Rob Wilson
To: ITRDBFOR@LISTSERV.ARIZONA.EDU
Sent: Sunday, 25 November, 2012 20:43
Subject: [ITRDBFOR] Comment to Mann et al. (2012) at Nature Geoscience
Dear Forum,
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
—
———————————————————————–
Dr. Rob Wilson
Senior Lecturer in Physical Geography
School of Geography & Geosciences
University of St Andrews
St Andrews. FIFE
KY16 9AL
Scotland. U.K.
http://earthsci.st-andrews.ac.uk/profile_rjsw.aspx
“…..I have wondered about trees. They are sensitive to light, to moisture, to wind, to pressure. Sensitivity implies sensation. Might a man feel into the soul of a tree for these sensations? If a tree were capable of awareness, this faculty might prove useful. ”
“The Miracle Workers” by Jack Vance
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UPDATE: RomanM locates the Mann paper in comments, writing:
The original Mann article seems to be available at his web site:
http://www.meteo.psu.edu/holocene/public_html/shared/articles/MFRNatureGeosciAdvance12.pdf
==============================================================
UPDATE2: More from the listserv
From: “Malcolm Hughes” <mhughes@LTRR.ARIZONA.EDU>
To: <ITRDBFOR@LISTSERV.ARIZONA.EDU>
Sent: Monday, 26 November, 2012 16:42
Subject: Re: [ITRDBFOR] Comment to Mann et al. (2012) at Nature Geoscience
> Ron – no dendrochronologists were involved in the offending Mann et al
> 2012 paper. What Rob described was the response of a number of us to
> some of the multiple flaws in the original paper. Cheers, Malcolm
>
> Malcolm K Hughes
> Regents’ Professor of Dendrochronology
> Laboratory of Tree-Ring Research
> University of Arizona
> Tucson, AZ 85721
—– Original Message —–
From: RONALD LANNER
To: ITRDBFOR@LISTSERV.ARIZONA.EDU
Sent: Monday, 26 November, 2012 03:48
Subject: Re: [ITRDBFOR] Comment to Mann et al. (2012) at Nature Geoscience
“a temporary cessation of tree growth” resulting in no rings for all trees? Now that is a hypothesis that I am willing to bet good money has no empirical support since studies of trees began 200 years or so ago. Speculation this bald could give dendrochronologists a bad name.
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UPDATE 3: Rob Wilson leaves this comment at Bishop Hill today, bolded section is my emphasis:
Nov 26, 2012 at 9:00 PM | 
Rob Wilson
Hi Again,
Our comment and Mann’s response to it can be accessed from this link:
http://www.st-andrews.ac.uk/~rjsw/all%20pdfs/Anchukaitisetal2012.pdf
his original paper is here:
http://www.meteo.psu.edu/holocene/public_html/shared/articles/MFRNatureGeosci12.pdf
Hmmm – what do I think of Mann’s response. Where does one start!
Well – he has provided NO evidence that there are stand (regional) wide missing rings for major volcanically forced cool years. Let’s focus on 1816 as an example – The “Year without a Summer” – where historical observations clearly show cool summer conditions (related to Tambora in 1815) throughout NE North America and Europe. Using either long instrumental records or historical indices, there is no evidence of a stand-wide missing ring in temperature sensitive tree-ring chronologies in Labrador, Scotland, Scandinavia or the Alps. Mann would probably turn around and say – well, actually, my model says that 50% of the sites would express missing rings – just not those in NE America and Europe. Sheesh!
To be less flippant, and putting aside criticisms of tree-ring series as proxies of past climate, the method of crossdating is robust and easily verifiable by different groups. I would be surprised if Mann has ever sampled a tree, looked at the resultant samples and even tried to crossdate them. He has utterly failed to understand the fundamental foundation of dendrochronology.
I undertook most of the analysis in D’Arrigo et al. (2006) and we clearly stated in the original paper that due to the paucity of sites (only 19) around the northern hemisphere, the reconstruction was most robust at time-scales greater than 20 years. Using the D’Arrigo reconstruction to look at inter-annual response to volcanically forced cool summers was a poor choice. Maximum density records, as shown in our response, would clearly be a far superior tree-ring parameter to use for such an exercise – as Briffa clearly showed in 1998. See also this paper:
http://www.st-andrews.ac.uk/~rjsw/all%20pdfs/D’Arrigoetal2009a.pdf
There is a lot more I could say, but this can all wait until next week at the AGU Fall Meeting.
One final observation is I urge you to look at Figure 1 in Mann’s original article. The instrumental record (black line) in Figure 1a (upper panel) clearly does not show strong cool temperatures in 1884 related to Krakatoa as seen in the two models. Following Mann’s hypothesis, the instrumental data must be wrong.
Time for some red wine
Rob
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Paywalled naturally. But given its output from the Mann, do I care enough to pay ? Nope. I’ll wait for Climate Audit or WUWT to run the errors, I have faith, its pretending tree rings sort of equal temperature, those pseudo-temperatures then smeared out across the world and then given great certainty by proclamation of the Mann. Or as described by another WUWT commenter, Garbage In Gospel Out. Maybe what I should be saying, is let the great one speak, give us more of your divine wisdom , Oh Great Doctor of the trees.Flattery is a better tool to encourage the true prat to spout on and the mann is too wonderful a tool to lose. Your call.
Cue the Mannian-grade righteous indignation in 3, 2, 1…..
I quote: “…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…”
Interesting. I have proved that volcanic cooling of the troposphere is a myth and that so-called “volcanic” cooling incidents are nothing more than accidental coincidences in timing of a La Nina cooling period with an expected volcanic cooling that is said to follow an eruption. Read pages 17 to 21 in my book “What Warming?” available from Amazon.
Oh Dear!
And just a few days ahead of the American Geophysical Union Fall Meeting ’12 Michael E. and Anthropocentric Mann Gala and Festival of Gay Warming Global non-Naturalis. The EGU at the General Assembly ’12 gave Mann a Gold Medal … for … well we are still trying to figure that one out but do not fret.
So ‘Naturally’ the AGU High Command Illumaniti MUST render a medal, some medal, any [snip] medal, to MEM and with Plaque and A life time membership … Oh they raised our membership fee from $20 to $50 just to pay for the ‘Supreme Executive and High Administrative Salaries’ … what [snip] THIS!.
Dirty Harry one proclaimed, “A Man’s Got’a Know His Limits!’.
Well, Mann did have the good sense to use BEST data in his response.
should make for an interesting discussion
REPLY: When is it ever good sense to use data that has failed to pass peer review? – Anthony
I am not a dendro but I have worked with and sampled trees in the very far north ±60. Some times you need a lens or a microscope to count the rings, they are very fine. I strongly suspect missing is simply not on. Maybe these people need to re-take Botany 101. More hypothetical baffle gab to cover your ass, Mike?
Ouch!!
This paper is spitting in the face of all his acolytes and pro-AGW robots who tried to proclaim his findings were viable and fact to all and sundry. How embarrassing! hehehe.
Was that previous tree ring, IPCC approved paper buddy reviewed too?
I have always had the feeling that Briffa wasn’t corrupted to the degree which some others seem to have been corrupted. Instead he seemed to be swept up by something he didn’t understand.
Briffa may have been involved in “hide the decline,” however all he did was find some data, be enthusiastic about what it “might” show, and then get a huge amount of praise for it.
I myself have seldom been praised for my ideas. Helpful people are swift to show me my errors. However on very rare occasions I have blundered into situations where I get praised. I can tell you, praise is exhilarating and intoxicating. You feel on top of the world, but it doesn’t last. Just as the depression of having your mistakes pointed out doesn’t last forever, neither does the euphoria of being told you are right. Sooner or later you get back to business.
I wonder if Briffa, unlike Mann, is getting back to business, the business being science.
Steven Mosher says:
November 25, 2012 at 7:02 pm
So did SkS,……
With all the errors introduced by Mann into climate science since 1998, a vast amount of manpower, time and resources have just been consumed for trying to clean this mess up and perhaps even consumed more for derailing such an effort.
So Mann is saying that for certain temperature years using the BEST data, the rings he looked for appear to be missing. I think what he means to say is that at certain times, trees do not make good thermometers. Is he trying to lay the ground work for justifying his “trick”? A preemptive strike perhaps?
I assume that Briffa will soon be in the dock along side Mark Steyn now that he has dared to question He Who Shall Not Be Questioned.
It has even been suggested – don’t remember where and by whom – that Briffa might have leaked the climategate mails. In the same period he disappeared somewhat from the scene due to health problems. I have no confirmation nor proof of this but his attitude is intriguing.
Eight months! to get published a letter questioning a paper.
Biffra should have come here. It would have been posted in it entirety in less than eight hours — and probably done more good for both sides of the debate.
I disagree. Briffa’s Yamal chronology is just as egregious as Mann’s original Hockey Stick. As far as I know, he hasn’t admitted that allowing ONE tree to overwhelm all the others in the recon was wrong.
Speaking of the BEST dataset, can someone tell me why the thing diverges so much from all other datasets?
http://i45.tinypic.com/23tqi3m.jpg
Isn’t it amazing that the need for empirical research into the characteristics of the proxies is now taken for granted. The ClimateGaters did not give it a thought. Just a year ago or so there were serious arguments on this website about the necessity of empirical research into proxies. Things are looking up in a serious way.
Reblogged this on Climate Ponderings and commented:
Mann has a bad day
So how does one demonstrate that a tree does not generate a ring under certain circumstances? Personally, I’m not a dendrocrat, but it would appear to be a convenient theory for some unknown purpose, for how would one know? Tree rings are not date stamped. What was the comment earlier about climate models… Garbage in Gospel out? The models can say whatever people are willing to believe. Who needs evidence, just propose a theory and say that you’ve modeled it.
“We look forward to a continued discussion on this subject.”
Not me. By the time they finish their discussions I will be cold or dead. I’m thinking cold first. But, maybe dead and cold in rapid succession. Anyway, trees can be used for all sorts of wonderful things but a thermometer isn’t one of them. One of the best uses is for charcoal and grilling steak, chicken, brauts . . . Set the carbon free! Cold is not good.
http://www.flickr.com/photos/kristinnwf/3190016130/sizes/l/in/photostream/
Will Mann cite Loehle next ? The dendros didn;t calculate on anything but unimodal response!
Go Mikey Go!.
Like cannibalistictadpoles – go go go guys!
Steyn on tap for this.
With regard to Keith Briffa, II think he always had reservations about conclusions others have drawn from his work. At worst, Briffa was used by Mann to foster his self serving Funding scheme…..more a victim than anything else, for which Michael Mann owes him both a professional and personal apology.
There are some real slimeballs in this whole sordid affair….Briffa is not on that list.
Steven Mosher says:
November 25, 2012 at 7:02 pm
Well, Mann did have the good sense to use BEST data in his response.
should make for an interesting discussion
=============
Have you anything of interest to say ?
Dendro wise, or just about BEST.
I’ll assume the latter, unpublished ? study.
On second thought, this has to be a mistake or I plotted this the wrong way, you can skip publishing my previous comment if you want.
A quote from Jack Vance, balsam for my soul…
Centuries from now Jack Vance shall be known as a “classic,” one of the “true great ones,” etc.
But never forget, Jack worked his butt out as a carpenter to support his family, while writing all those wonderful books. That’s how our progressive society of unionized educators, editors, gamers, pot smokers, food stamp recipients and Peace Corps volunteers having fun on a public dime in South Seas rewards a real talent.
P.S. More evolved (and hair-raising) view of trees’ capability of awareness see in Jack Vance’s masterpiece, Maske: Thaery.