The Neo Paleo Twitter war of Mann -vs- D'Arrigo

It seems that Columbia’s Rosanne D’Arrigo thinks Mann’s tree ring study isn’t representative proxies for volcanic eruptions, nor good for dendrochronology, though Mike Mann seems to think so. This Twitter interchange via Alexandra Witze from the AGU Chapman Conference on Volcanism and the Atmosphere in Selfoss, Iceland 10–15 June 2012 tells the story:

And Witze goes on to say that there’s a rebuttal paper in the works, but Mann is not amused. Mann responds (TRW means Tree Ring Width):

I still don’t think Dr. Mann has a basic handle on Liebigs Law.

Its seems a rebuttal is in the works

(h/t to Tom Nelson)

Here is what the Twitter fight is all about, this paper published in February:

Abstract from Nature Geoscience here

Underestimation of volcanic cooling in tree-ring-based reconstructions of hemispheric temperatures

Michael E. Mann, Jose D. Fuentes & Scott Rutherford Nature Geoscience (2012) doi:10.1038/ngeo1394

Received 14 June 2011 Accepted 11 January 2012 Published online05 February 2012

The largest eruption of a tropical volcano during the past millennium occurred in AD 1258–1259. Its estimated radiative forcing was several times larger than the 1991 Pinatubo eruption1. Radiative forcing of that magnitude is expected to result in a climate cooling of about 2 °C (refs 2, 3, 4, 5). This effect, however, is largely absent from tree-ring reconstructions of temperature6, 7, 8, and is muted in reconstructions that employ a mix of tree-rings and other proxy data9, 10. This discrepancy has called into question the climate impact of the eruption2, 5, 11.Here we use a tree-growth model driven by simulated temperature variations to show that the discrepancy between expected and reconstructed temperatures is probably an artefact caused by a reduced sensitivity to cooling in trees that grow near the treeline. This effect is compounded by the secondary effects of chronological errors due to missing growth rings and volcanically induced alterations of diffuse light. We support this conclusion with an assessment of synthetic proxy records created using the simulated temperature variations. Our findings suggest that the evidence from tree rings is consistent with a substantial climate impact2, 3, 4, 5 of volcanic eruptions in past centuries that is greater than that estimated by tree-ring-based temperature reconstructions.

Growing-season statistics.

Figure 3 Growing season statistics
a,b, Estimated average length of the growing season (number of days of non-zero growth) based on the biological growth model driven by the GCM simulation without stochastic weather forcing (a) and with stochastic weather forcing (b). c, Forcing missing

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Hyperthermania

It just goes to show that you need to keep your Witze about you 😉
(Sorry, really sorry…)

pat

Botanists have been saying climatologists were cranks fro years.

Mac the Knife

This has all the hallmarks of a small mann snit, headed for a tiff… or even a full blown huff!
“..Promises fireworks at poster session.” Oh Goody! I love fire works, what with the 4th of July coming up and all!

Jimmy Haigh.

For the purposes of “climate science”, tree ring width means whatever Michael Mann wants/needs it to mean.

Anopheles

It’s dendro AND it’s a model. Indisputable then.

Am so glad I don’t live in Michael Mann’s world, surrounded by evil enemies lurking everywhere and forever misrepresented. No wonder he doesn’t accept debate or even dialogue.

I still don’t think Dr. Mann has a basic handle on Leibigs Law.
He doesn’t believe that Leibig’s Law should apply to his work — he certainly doesn’t believe that the FOIA applies. Besides, the only handle he’s concerned with is on his hockey stick.

Espen

I don’t think historic records support anything special about 1259. There was a famine in England, but it started in 1257, and was most likely due to bad government, not weather events.
I think the most likely explanation here is that “volcanic forcing” isn’t as simple as modelers want it to be…

Roy

Twitter? Really? Why would anyone pay any attention to the kind of people who snipe at each other on Twitter. Grow up all of you.

braddles

People are trying to rebut and debate scientific papers using 140-character Tweets? What is going on in science? I don’t care who is right, this is insanity.

braddles says:
June 15, 2012 at 12:38 am
People are trying to rebut and debate scientific papers using 140-character Tweets? What is going on in science? I don’t care who is right, this is insanity.

It’s the logical extension of post-modern science.
Sorry for using “logical” and “post-modern science” in the same sentence…

Hans Henrik Hansen

“I still don’t think Dr. Mann has a basic handle on Leibigs Law” – you refer to Liebig’s Law? Or am I missing some finer point??
REPLY: Misspelling fixed, thanks

I do not understand the NEED to “Tweet”. I do not understand how so many otherwise media-savvy persons can so comprehensively beclown themselves whilst “Tweeting”.
Why does this happen with such an exponential increase in self-beclownments? Not only that, but a permanent trail of one’s idiocy will last the human equivalent of “forever”.
Stupid is as stupid does…….

Otter

Bill Tuttle says:
Besides, the only handle he’s concerned with is on his hockey stick.
——-
Rats, I So want to take that to its’ natural conclusion…!

DirkH

Revenge of the dendros?

Brian H

Liebig’s Law of the Minimum is inaccurate; unlimited nutrients and sunshine will not produce a cornfield with infinite yield, e.g.
Here’s my improvement:
Brian’s Barrier: when one limiting factor is removed, there’s another.

Brian H

Tweets are twiffic if you want to tersely tweak or twit, otherwise twivial.

John Brisbin

Now there is Liebig’s Law, which might be in this case be transposed to the Law of the Big Lie, courtesy of Hitler, which then immediately terminates the discussion to comply with Godwin’s Law.
At least, no lawyers had to be paid.

Claude Harvey

Science has been reduced to soap opera status. “Tweeting” back and forth? How “manly” is that? Now that I think about it, how “manly” is the “he said, she said” exercise in which we are currently engaged? Think I’ll go chop some wood or, as Willis is inclined to say, “Pound some nails”.

Manfred

This extensive use of twitter garbage just substantiates the assumption that Mann is not able to defend his positions in a profound scientific discourse.

Georgegr

What is the difference between Mann and his tree rings and an old lady and her tea leaves?
Answer: Not much…

H.R.

140 characters will barely cover a snit and Twitter is totally inadequate for a decent rant or diatribe. I’ll wait for the paper to come out.
@Hyperthermania says: June 14, 2012 at 11:45 pm
Hey! That was a great way to start off the thread. Nicely done.

mycroft

For some one who in his own words didn’t want the hockey stick to become the “be all of climate science/ipcc”, Mann is sure defending it and the methodology behind it?

While Mann and the rest of the gang are concentrating on the tiny smears on the dial of the solar system’s clockwork, there is little hope of understanding of climate, geo or solar oscillations. Current crop of scientists is letting down humankind by failing to follow in footsteps of great minds of the past centuries.

tonyb

Espen said;
“I don’t think historic records support anything special about 1259. There was a famine in England, but it started in 1257, and was most likely due to bad government, not weather events.
I think the most likely explanation here is that “volcanic forcing” isn’t as simple as modelers want it to be”
I agree with you. Sorry for the length of this post but it is highy relevant to the topic; I had this same conversation a couple of weeks ago in another place with, amongst others, R Gates who used to post regularly here;
As it happens I am writing a article on the period from around 1200 to link up with my study which reconstructed CET back to 1538. I am especially interested in its impact locally and on the nearby uplands of Dartmoor.
. In consequence I have been looking in the archives of the medieval Exeter Cathedral, The Met office and Devon records office and been examining original scrolls dating back to the 13th Century. Consequently what folows is based on actual contemporary observations. Its unedited so hope it makes some sort of narrative sense;
—– —— Exchange started as follows——–
“Having now spent some time looking at evidence on the ground and written documentation in a variety of places I would look askance at science, as recently evolved in the form of ice cores and marine cores, in relation to this statement by the very eminent Jean Grove, an LIA scholar at Cambridge University (who died several years ago) and wrote;
“… marine cores taken off the southeast coast of Greenland showed warm stable conditions between 10th and 13th century followed by cold conditions beginning about 1270 and culminating probably about 1370 and a brief interruption 1370 to 1470 did not involve reversion to the relative stability and warmth of the MWP.”
I can see no empirical evidence for this downturn in 1270, indeed it seemed to contain some of the warmest years in our record. There are very many pieces in the climate jigsaw and I doubt anyone has found them all or knows how to assemble the whole.
tonyb
 R. Gates | May 31, 2012 at 7:35 pm | Reply
Tony,
You said:
“I can see no empirical evidence for this downturn in 1270…”
_____
Of course I would hope you are kidding. There were a series of very large volcanic eruptions around the time of 1250-1300. The cooling affect from the release of those volcanic aerosols would be something for you to consider as potential “empirical” evidence. Ice Core data clearly shows these eruptions as occurring. But I assume you knew all this…see:
http://www.bbc.co.uk/news/science-environment-16797075
But of course, changes in solar uv output also played role in the LIA, most notably in the later periods. But early on, it seems volcanic aerosols might well have kicked the whole party off to a cool start.
 climatereason | June 1, 2012 at 1:18 pm | Reply
R Gates
Of course I knew that. The written records shows for example the extreme cold caused by Icelandic eruption in the 1700′s but not ones in the period I referenced. That is not to say they didn’t happen, but written evidence to date does not show it. Reliable written evidence trumps ice cores.
tonyb
 Steven Mosher | June 1, 2012 at 1:34 pm |
Funny. how do you calibrate a written record? how do you determine it is ‘reliable’ when reliable means “captures the temperature accurately” faced with a ice core that showed an eruption ( global of course and of the the right size ) and a written record that failed to record cooling, I’d take the physical evidence over the record of humans. face with a contradiction between these two ( an ice core that indicated cooling and a written record that recorded “warmer” ) I’d still take the ice core record.
 Louise | June 1, 2012 at 1:49 pm |
“Reliable written evidence trumps ice cores.”
Translation: “anecdote trumps data”
 ceteris non paribus | June 1, 2012 at 2:06 pm |

Reliable written evidence trumps ice cores.
”Card-playing metaphors do not entail that two types of evidence equals a dilemma.
 climatereason | June 2, 2012 at 3:51 am |
Mosh
I suggest you read A F van Engelen/J Buisman/F Unsen of the Royal Met Office de Bilt who describe how you convert non instrunental information by putting them into 11 categories. (see History and Climate’ edited by Briffa/Jones/Ogilvie and Davies)
We have numerous records and are always searching for more, and these can be converted into reasonably accurate temperatures when they can be categorised. My ‘ The long slow thaw’ estimates are pretty close to those from De Bilt as I used this method of classification- despite what you think its not a ‘finger in the air.’
Records I researched from the Medieval Exeter Cathedral included these
1697 Charity payment to poor in severe weather
1702 and 1705 storm damage to church roof
1703 trees blown down in Cathedral Close by storm –December
1740 January ‘£23 to be given to poor in consideration of the severity of the season.’
1783 ‘Extra poor relief in extreme cold’ (due to Iceland volcano?)
I would take stuff written down by people who were there at the time rather than cores which may reflect an event but not its real world effect
Tonyb
 R. Gates | June 2, 2012 at 9:45 am |
Tony,
I’m just not sure where you are actually coming from on this. You wondered about the cause of the cooling in the time frame around 1270-1300– cooling which you admitted to having occurred– and when I pointed out the very solid evidence of a series of large volcanic eruptions in this time frame as documented by ice core data, you suggest “observations trump data”. What observations are you referring to? The Vikings were experiencing increasingly foul weather in their Greenland colonies in this same time period– the same time period that the ice cores in Greenland show large volcanic eruptions were cooling the globe.
 climatereason | June 2, 2012 at 10:45 am |
R Gates
No, please read my post, I didn’t say there was cooling around 1270-1300.It was the eminent Jean Grove who said it.
I said I couldn’t find any written evidence to support this (in the area I am talking about) in fact there is continued evidence of habitation on the High moors around here right through this period, and the Cathedral records have this to say;
‘The winter period was defined as the beginning of November to the end of the 11th or 12th weeks of the Christmas term-so winter lasted up to 20 weeks (note subsequent change of calendar) During this period (1279 to 1353) ‘the work force was much reduced in number on account of the weather, (in the winter) though work does not seem to have ever altogether ceased on this account.’
Just because there were signs in a core of a volcanic event around 1270 doesn’t mean this had a real world impact. However, I need to do much more research before I would disagree with someone like Jean Grove.
Louise said (and I assume that you and mosh would agree;
“Translation; anecdote trumps data”
However if the written record(s) were good and the data unsubstantiated, which would you go for? ‘Data’ because it is deemed to be scientific? Ideally both need to corroborate each other
tonyb
 manacker | June 3, 2012 at 8:24 am |
steven, tony b and louise
Today’s (reconstructed) “ice core data” is recorded by human beings.
Past (historical) climate data was recorded by human beings.
If the historical data include crop records, etc., they are “harder data” than the ice core stuff.
To write historical data off as “anecdotal” (and hence inferior in quality) would be asinine. (But I’m sure that’s not what anyone is doing here.)
Max
 gbaikie | June 2, 2012 at 11:20 am | Reply
“Ice cores from both the Arctic and Antarctic record a massive volcanic eruption in around AD 1258. The inter-hemispheric transport of ash and sulphate aerosol suggests a low-latitude explosive eruption, but the volcano responsible is not
known. This is remarkable given estimates of the magnitude of the event, which range up to 5 × 10^14–2 × 10^15 kg”
http://onlinelibrary.wiley.com/doi/10.1002/joc.891/pdf
So this unknown eruption was bigger than Tambora.:
Wiki: “With an estimated ejecta volume of 160 km3 (38 cu mi), Tambora’s 1815 outburst was the largest volcanic eruption in recorded history.”
160 km3 or say 320 trillion kg- 3.2 x 10^14 kg.
So unknown eruption is seemingly much bigger than Tambora.
Both these scales of eruption utterly dwarf the ones in more modern times.
Mount Pinatubo[1991]: 1 X 10^13 and Krakatoa[1883] : 4 x10^13
So around AD 1258 an eruption as much as 200 times more ejecta
Pinatubo, or perhaps as small as 10 times more than both of them combined.
 R. Gates | June 2, 2012 at 2:04 pm |
Though there was a very large one around 1258, it wasn’t the only one as Ice core data show several lessor ones, but still larger than Pinatubo.
 climatereason | June 2, 2012 at 3:18 pm |
R Gates
uncertainty in the 1258 record
http://www.wired.com/wiredscience/2012/02/the-mysterious-missing-eruption-of-1258-a-d/
tonyb
 climatereason | June 2, 2012 at 3:36 pm |
gbaikie
the paper says it could have been a small eruption that was sulfur rich. The evidence for the severe cold seems to come from tree ring reconstructions.
tonyb
——– End of exchanges——

g3ellis

Why does that idiot keep thinking temperature is causal? I keep looking for temperature in the Kreb cycle and I just can’t find it.

manicbeancounter

So let me clarify.
– A massive blip temperatures caused by natural phenomena does not show up in tree-ring proxies.
– Tree ring proxy-based reconstructions show that C20th warming is greater than anything in the past 1,000 years.
– These reconstructions are then fed into climate models that try to estimate the influence of known forcings such as solar, CO2 – and volcanic activities. (See Gergis quote below)
– As the biggest fluctuation in the reconstructions is the C20th uptick, and the only extreme phenomena in C20th not present in others centuries is the increase in greenhouse gas levels, then anthropogenic forcings are the major recent driver of global warming.
Like with the post 1960 decline in tree-ring proxy temperatures, Mann, Fuentes and Rutherford show that tree ring proxies fail to pick up known global temperature fluctuations. By implication, they provide further corroboration for claims that climate models exaggerate the influence of CO2.
From Gergis et al. 2012 abstract

A preliminary assessment of the roles of solar, volcanic, and anthropogenic forcings and natural ocean–atmosphere variability is performed using CSIRO Mk3L model simulations and independent palaeoclimate records. Solar and volcanic forcing does not have a marked influence on reconstructed Australasian temperature variations, which appear to be masked by internal variability.

Peter in MD

So this is what “science” has come down to:
“We support this conclusion with an assessment of synthetic proxy records created using the simulated temperature variations.”
SO we synthesize proxy records? What about all the other variables? Sunlight, moisture content, particulate matter…….. all the others I can’t come up with…….
I wonder if Mr. Mann uses models to predict how his day is going to go, or week, or month or year?

Katherine

Here we use a tree-growth model driven by simulated temperature variations to show that the discrepancy between expected and reconstructed temperatures is probably an artefact caused by a reduced sensitivity to cooling in trees that grow near the treeline.
Yeah, it couldn’t be that the model is wrong, now could it?
/sarc
Models all the way down.

Heck, Anthony, the yield of plants is so much more complicated than we imagine, way past Leibig’s Law. For example ,it is known from controlled studies that some elemental nutrients like molybdenum and zinc also interact with pH (which is on a log scale) and that pH interacts with the availability of calcium or vice versa, which can affect the solubility of some relevant molybdenum compounds. Even common old iron has problems being ferric or ferrous, a chloride, an oxide a suplhate or a synthetic chelate. It’s a fun game to find the dependent variable sequence and also the number of interacting variables in a particular biochemical cycle and also whether they interact on a linear basis of concentration or a curved one, even an inverted U.
Climate workers have this fixation with relating all and sundry to temperature, to the detrimental neglect of old-fashioned chemistry and physics. That’s strange, because they can’t even describe why their own bodies maintain almost constant temperature (without periodic historic adjustment), but they are very wise about tree rings.

boston12gs

If one removes all the “tree-ring reconstructions” “tree-growth model” “driven by simulated temperature variations” “reconstructed temperatures” “probably an artefact” “assessment of synthetic proxy records” “simulated temperature variations” is there anything real left in this paper, or is it merely a mental exercise with no real-world data whatever?

henrythethird

braddles said (June 15, 2012 at 12:38 am)
“…People are trying to rebut and debate scientific papers using 140-character Tweets? What is going on in science? I don’t care who is right, this is insanity…”
In Dr Mann’s case maybe all his “climate science” papers should be limited to 140 characters.
Harder to get things upside-down that way.

Jak

“Skeptical empiricism, the kind exemplified by the carefully thought-out and tested research in science at its best. It differs from plain empiricism” — which is simply the observation of results of the world around us. Put more simply, it is important for us to be skeptical about the world around us and not blindly accept what we believe to be “truths.”
Gerald Holton, professor of physics and the history of science, Harvard University

Now, a comment about the paper itself:
From the abstract – “…The largest eruption of a tropical volcano during the past millennium occurred in AD 1258–1259. Its estimated radiative forcing was several times larger than the 1991 Pinatubo eruption. Radiative forcing of that magnitude is expected to result in a climate cooling of about 2 °C. This effect, however, is largely absent from tree-ring reconstructions of temperature…”
Considering that most tree ring reconstructions used carefully selected data designed to show the RECENT warming (CAGW), it’s no wonder that they failed to catch any past variation.
Sounds like he’s trying to defend the handle of the stick, here.
I’ll bet that if they re-screened their tree data, they’d find LOTS of trees that show an effect from this eruption.
Of course, those trees probably wouldn’t show the current warming.

Handbags at dawn …
Pointman

Should have seen this the first time:
“…We support this conclusion with an assessment of synthetic proxy records created using the simulated temperature variations…”
They used synthetic proxies and simulated temp variations to prove a point?
No wonder people question the methods used by “climate scientists”.

I await the “War with Posters” with heart aTwitter (sic). Can’t believe PSU is paying Mr. Mann to put out ridiculous tweets calling others names. GET A JOB.

Sort of on a tangent, my heart is warmed by seeing a Science News correspondent question something from the warmists. I’ve subscribed continuously since 1969, and credit them for being able to talk with pretty much any scientist without wasting his time. Unfortunately, their environmental reporter and blogger is active in the Society of Environmental Journalists, which had been strongly warmist activist (see http://www.sej.org/initiatives/climate-change/overview ). They seem to have tempered things a bit after Rajendra Pachuri was the keynote speaker at their annual meeting. I haven’t followed the SEJ too closely so I can’t point to specifics. I did invite her to the ICCC in Washington last year, but as far as I know, no one from SN attended.
I and others I recognize from WUWT have commented on some items in the SN blog that are uncomfortably one sided. They’ve deleted a couple of my comments (I think they don’t like my Eisenhower references about gov’t funded science and policy), but sort of tolerate me.
It’s frustrating seeing their AGW bias, but I did renew for a couple extra years last month as it remains a very good springboard to current developments, especially with their reports from conferences.
Gotta go find a contact address for Alexandra Witze and send her a thank you note. SN doesn’t make it easy and I’m not joining Twitter.

g3ellis says:
June 15, 2012 at 3:03 am
> I keep looking for temperature in the Kreb [sic] cycle and I just can’t find it.
The Krebs Cycle describes the chemical steps of metabolism. It doesn’t describe the rate, and anyone looking at the Kreb cycle should be aware that temperature affects the rate of many enzymes.
Yes, I understand you’re being sarcastic, but that’s no reason to feign ignorance.
Also, The Kreb Cycle is only indirectly related to the Krebs cycle, see http://krebcycle.com/ 🙂

OK, folks, welcome to the world of science. You may not have known this but scientists disagree with each other all the time. Hence why the idea of “they” and “them” working together on a “climate agenda” is so ridiculous from a scientist’s perspective.
Mann and D’Arrigo are both having a healthy scientific debate. They’re doing so at the AGU scientific conference, with some spill over onto Twitter (with such scandalous language as “terribly dishonest” and “misleading”). But the real scientific debate is in the peer-reviewed papers, where it should be.

Note to Mike – be careful how much you debate volcanoes with Witze, read http://scicom.ucsc.edu/about/program-news-articles/2012-01-witze.html and she has a geology degree from MIT, http://www.environmentwriter.org/scienceandthenews/bios/awitze.htm .

Chuck L

Knowing Mann’s propensity to be unable to keep his mouth and Twitter account shut, this could get very entertaining, very fast! Popcorn, anyone?

Espen

tonyb, thanks, very interesting!

RockyRoad

Maybe Mann can put the sum total of his relevant science in a single Tweet. Or maybe not.
To tweet or not to tweet, that is the (scientific) question.
(I’ve never seen anything so absurd–Mann is off his tweets.)

ferdberple

Liebig’s Law
Lie Big and carry a hockey stick.

ferdberple

henrythethird says:
June 15, 2012 at 4:32 am
I’ll bet that if they re-screened their tree data, they’d find LOTS of trees that show an effect from this eruption. Of course, those trees probably wouldn’t show the current warming.
=========
Exactly right.
At one time, the best indicator of the stock market was the height of snowfall in a small mid-western town. For decades. lots of snow that winter, the market went up that year. Very little snow, the market went down. Using the “screening” approach common to climate science and most of the social sciences, for some unexplained reason the market recently diverged from the snowfall records. Probably a result of CO2 contamination.
These sorts of accidental correlations occur all the time. If you start with a big sample of trees, you will always find some trees that match anything you want. Be it temperature or the stock market. That doesn’t mean that these trees will match anything outside the study period. Unless of course they happen to support the conclusion you are trying to promote.
What we are seeing in the long sad history of tree ring “science” is nothing more than phrenology. Predicting intelligence based on the number of bumps on your head, as a result of studying only those people where the bumps do match intelligence. Those people where the bumps don’t match? We leave them out of our study using a screening process called “calibration” in which we calibrate the bumps to the subjects intelligence.

COB

Dr. Mann seams to be a bit of a Twit.

HR

So scientists disagree. Yep!
So a health discourse is going on in climate science. Great!
Once you get passed the Mann bashing there’s much here that undermines those that believe the climate science community is involved in some sort of collective confirmation bias process.

ferdberple

“..Promises fireworks at poster session.”
Sounds like someone is making a death threat against a climate scientist. Actually, it does sound like a threat is being made. Who was the person making the promise? They appear to be making a threat.

Skiphil

I want to highlight one of Michael Mann’s tweets reproduced above:
========================================================
Michael E. Mann ‏@MichaelEMann
@alexwitze D’Arrigo claim our study provides fodder for #climatechange #deniers terribly dishonest. Its just the opposite [cont] #AGUVolcAtm
========================================================
Even in this strange shallow Twitter world, it is stunning when one prominent scientist calls another “terribly dishonest” — it’s not even clear why it would be a question of honesty, since the point about what may provide “fodder” for evilllll climate change skeptics really gets more into a grey area of opinion.
But it is so typical Michael Mann and his scorched earth rhetoric, disagree with him and you are “terribly dishonest”!!!
I hope that D’Arrigo and many colleagues are starting to understand the deleterious influence of Michael Mann in a wide variety of contexts. Surely scientists should be able to debate the implications of a study without one calling another “terribly dishonest” for a difference of opinion.