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
———————————————————————–
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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Briffa is on the short list of those who have fought tooth and claw to prevent scrutiny of their data,which data, when finally obtained through FOI, revealed his science as so faulty as to approach fabrication. If Briffa now embraces the scientific principle of reproducibility, it is a reversal of his previous behavior. He deserves no praise as a scientist.
One tree ring to rule them all,
One tree ring to find them
One tree ring to bring them all
And in the darkness bind them …
Somebody had to do it.
FYI R Wilson has just posted another interesting comment at BH last comment.
Hi Knoebel
1. You say:
Your graph includes the note on the 30-day averaging. But you have obviously not used the filtered data, which is described (with incorrect grammar)
Sorry mate, it’s pure Americana quoted from:
http://wso.stanford.edu/Polar.html
“Each 10 days the usable daily polar field measurements in a centered 30-day window are averaged.”
line 7.
2. You say
. But you have obviously not used the filtered data…..
Polar field represents strength of the solar dipole, which is simple North-South. On this you should consult one who knows and understand these matters, and whose advice I have taken, and that is indeed our very own Svalgaard of Stanford
http://www.leif.org/research/WSO-Polar-Fields-since-2003.png
Graph two (he hasn’t updated yet, the new data are published only this afternoon); note Dr.S has inverted scale, I use the normal ordinate orientation.
Plotting and updating moving filtered data is associated with a problem which you may or may not be aware of (again refer to Dr.S).
In some mature coniferous forests, the lower tree branches die due to lack of light. Individual trees eventually consist of small crowns atop a tall branchless stem. Diameter growth is initiated in the crowns and indeed, in this area a ring is formed every year. Diameter growth then moves from the tree crown down the stem forming a ring as it goes. This is why some coniferous stems appear to have little taper. In some years and in some trees there may not be enough vigour for growth to reach the bottem of the tree and a ring will not be formed all the way to the base. This will not likely be detected when aging trees by boring but will be found with destructive analysis of the tree.
==================================================================
Mughal, I think you have quite missed the point. It is Michael Mann and his team who have made it exceedingly difficult to have candid discussions of (putative) mistakes or corrections without turning everything into a bloodbath of accusations and hostility. It is now FOURTEEN years since MBH98 and (so far as I am aware) there is still no full and adequate defense of MBH methodology and error analysis. Had Mann engaged in honest, candid, cooperative discussions at any time in the past 14 years much more could have been achieved, and enormous amounts of wasted time and energy (for many people) avoided.
This is a different era (obviously) from times when science could be “self-correcting” over many generations — to the extent feasible we want the sciences (especially when they have public policy or medical etc. implications) to be self-correcting just as rapidly as feasible.
It is Michael Mann and his teammates who have thrown up far too many obstacles and raised the time/cost for correction.
Fourteen years is now long enough (more than) — perhaps this little “revolt of the dendros” can spark a general re-assessment of Mann’s articles and everything that has gone wrong over 14+ years.
yes it is encouraging to see some of the names on this list of 23, daring to challege the Mann-iac’s egomania…… I find it a hopeful sign to see these particular names (below) under the comment, since all of them now have reason to recognize the obstacle to scientific progress represented by Mann’s “air of papal infallibility” (a phrase once applied to Bradley but perfectly suitable for Mann):
Keith R. Briffa, Edward R. Cook, Rosanne D. D’Arrigo, Jan Esper, Malcolm K. Hughes, Thomas M. Melvin, Rob J.S. Wilson
@ur momisugly Truthseeker says:
November 26, 2012 at 2:16 pm
One tree ring to rule them all,
One tree ring to find them
One tree ring to bring them all
And in the darkness bind them …
Somebody had to do it.
Yes, somebody had to do it and just in time for the movie, too.
From vukcevic on November 26, 2012 at 2:31 pm:
Sorry mate, it’s pure Americana quoted from:
http://wso.stanford.edu/Polar.html
“Each 10 days the usable daily polar field measurements in a centered 30-day window are averaged.”
Incorrect. I referred to that site and the mentioned low-pass filtering with its note, not the 30-day unfiltered values with that note which you copied on your graph. You have not used this data with the low-pass filtering, as I have stated.
Plotting and updating moving filtered data is associated with a problem which you may or may not be aware of (again refer to Dr.S).
Who advised using the smoothed sunspot number for solar research. Smoothing/filtering has a place, use enough to reduce spurious noise, not enough to suppress or alter details.
The “dendro” fight has been going on 4+ decades. Has anyone been in the field using luminance, humidity, moisture, precipitation, temperature, CO2, trace, etc. at reference sites to actually confirm “tree ring” observations?
skiphil says:
“yes it is encouraging to see some of the names on this list of 23, daring to challege the Mann-iac’s egomania”
Wait a minute. I thought there was some grand cabal who washed each other’s backs, and threatened editors to ensure one and only one message got out there?
Are you saying that model no longer holds?
Mughal says:
November 26, 2012 at 4:15 pm
In the grand tradition of Climate Science™, obviously the data are wrong and the model is correct. So the fact that we can’t account for the missing praise of Michael Mann is a travesty. One that no doubt can be corrected for, given enough time, and enough careful readings of the listserver. Perhaps the missing praise is present at the very deepest levels of the SQL memory architecutre and not evident at either the surface or the intermediate levels.
Sorry, Dr Lanner – too late!
I have all sorts of trees currently experiencing a ‘cessation in tree ring growth’ as a result of last years’ drought in Texas. But here’s to hoping that they magically spring back to life!
;-D
Oh dear Mikey and the team are having a bad month it seems..some headlines from The Hockeyschtick from November
1.New paper contradicts IPCC assumptions about precipitation
2.New paper shows no “hot spot” as predicted by climate models, invalidates AGW
3.New paper shows global warming leads to fewer floods
4.New paper finds urban heat islands can account for up to 2°C warming
2.New paper shows N. Atlantic Ocean cooled from 1953-2007
And now Mikey gets whipped with his tree ring Trick..is it me or are the rats leaving a sinking ship
and heading for dryer ground so to speak???
.
Mycroft, do you have links to those specific papers, particularly #4
Thanks.
John M says:
“In the grand tradition of Climate Science™, obviously the data are wrong and the model is correct.”
So scientists can’t win? The data is wrong, or the model is junk. That’s what you’re saying.
Skeptics spend a lot of time telling us how this is all a hoax and all scientists are in cahoots to promote an AGW-view. Yet now some scientists are disagreeing with one of their acolytes. So what are we supposed to believe — that the scientific community really IS concerned with the truth?
Mughal says:
November 26, 2012 at 4:15 pm
skiphil says:
“yes it is encouraging to see some of the names on this list of 23, daring to challege the Mann-iac’s egomania”
Wait a minute. I thought there was some grand cabal who washed each other’s backs, and threatened editors to ensure one and only one message got out there?
Are you saying that model no longer holds?
Actually, what ClimateGate taught us is that it was a relatively small “cabal” which was driving the message. This is precisely an example of that cabal (and, to continue your metaphor, their “model”) meeting the larger scientific community.
You think it must have been “grand” because you think that there really is/was some kind of “consensus”
Mughal:
At November 26, 2012 at 5:44 pm you ask:
No, your question demonstrates several misunderstandings.
The ‘Team’ is not part of “the scientific community” but is a group of pseudoscientists who – as their own words in the climategate emails demonstrate – have conspired to further their careers by destroying both the scientific method and the scientific publication system.
Their conspiracy attempted to continue the AGW-scare which encouraged politicians to fund their activities. But at Copenhagen in 2009 the politicians decided to abandon the scare so the Team’s funding is threatened.
The failure at Copenhagen was certain to eventually result in the failure of the Team’s conspiracy. And the Team is falling apart while searching for scapegoats. It seems that Mann is being selected to wear cloven hooves.
Richard
Rob Wilson said on: ITRDBFOR@LISTSERV.ARIZONA.EDU
Sent: Sunday, 25 November, 2012 20:43
“…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…”
—————————————————————–
Lack of any empirical evidence – that about sums up AGW theory.
Mughal:
At November 26, 2012 at 5:44 pm you ask
No, your question displays much misunderstanding.
The ‘Team’ is not part of “the scientific community”. Their own words in the climategate emails reveal the ‘Team’ to be a cabal of pseudoscientists who conspired to further their “cause” by usurping the scientific method and distorting scientific publication procedures.
And what they call “the cause” is promotion of the AGW-scare to further their careers.
But at Copenhagen in 2009, politicians decided to withdraw from the scare, and politicians (directly or indirectly) most of the Team’s funding. Thus, the Team fear the imminent failure of their conspiracy.
The Team is seeking a scapegoat and it seems that Mann has been selected to stand on cloven hooves: in a way he has selected himself by his arrogance and demeanour.
Richard
Skeptics spend a lot of time telling us how this is all a hoax and all scientists are in cahoots to promote an AGW-view.
“Sceptics” do no such thing. Some opposed to the AGW line do this, but far from all. Not even most by a long shot.
Go the sites where the science is discussed in detail (CA, Lucia, etc) and you find nothing remotely resembling the position you outline above.
If you walk around pretending that everyone sceptical of AGW is taking the same line “hoax” and “conspiracy”, then prepare to have people ignore you. Only someone deliberately being obtuse would do that.
Maybe Mann should look under the table skirt for his missing data.
Mughal says:
November 26, 2012 at 5:44 pm
Um, well, it has to be one of those, cause the data certainly are not agreeing with the model(s). Generally speaking, when observation does not agree with hypothesis, hypothesis needs adjustment.
No they don’t, not even close. That’s simply what you want them to be saying. I think the psychological terminology that would be appropriate is projection. If the tables were turned, that’s what you would be doing, therefore, that’s what skeptics are doing.
Yay, it’s about time.
Maybe we should believe that eventually the truth will out? I won’t even point out that there are still rather many people defending the nonsense that Mann spews forth. Just because those on this list finally got to the breaking point at which they could no longer keep quiet does not in anyway mean that the “scientific community” writ large is on board as well. Ideology is a difficult thing to break – it is not arrived at through logic and reason, and thus cannot be broken by the same.
Mark
Yeah, I always right-click and open link in new tab (Firefox), and they weren’t working, even just a minute ago. The error was a “Page Not Found”, so probably a custom 404 error page. So I did a “copy link location” and pasted into a new tab, and both worked. Strange.
Thanks!
Agree completely. He will have to admit, publicly, past mistakes which are blatantly obvious. Then, maybe, I can trust him as a scientist.