Steve McIntyre has a new analysis up, one that has a strong headline.
Though as he says, “not in so many words”, but more about techniques and exclusions. He writes:
Briffa Condemns Mann Reconstructions
Not in so many words, of course. However, Briffa et al 2013 took a position on the use of radially deformed tree ring cores that would prohibit the use of strip bark bristlecones in temperature reconstructions, thereby emasculating Mann’s reconstructions. And not just the Mann reconstructions, but the majority of the IPCC reconstructions used by Briffa in AR4.
I’ll report on this issue in today’s post. I’ve been looking closely at Briffa et al 2013 over the past 10 days and unsurprisingly there is issue after issue. According to CRU, they’ve been working on this article for over seven years and, needless to say, it is impossible to fully observe the pea in only a few days, especially when the adjustments have become so baroque that the chronology style is most aptly described as East Anglia Rococo, making the weary reader long for the classic simplicity of earlier CRU illusions like the Briffa Bodge and Hide the Decline. But more on this on another occasion.
full post here: http://climateaudit.org/2013/06/16/briffa-condemns-mann-reconstructions/
When in doubt, bite your collaborator’s arse. That’s the sort of classy sh*t you’d expect of leather-tailed rodents abandoning a buoyancy-compromised aquatic conveyance, don’t you think?
I have always been puzzled by the picture of Michael Mann holding the cross-sectioin of a tree, presumably showing the tree rings he measured to get the proxy for temperatures in the past.
Is it THE tree that gave the upturn to the hockey stick? IT shows distinct damage at an early stage of growth (caused by felling nearby trees?) which could have restricted its growth rate, and then it could have accelerated growth in the absence of competition for light, nutrients and water. (Light and water availability have been the major influences in tree growth in my experience of growing trees). Along which radius do you measure it? There seems to be plenty of scope for cherry-picking.
Help me out here someone. Tree rings are believed to be reliable regional thermometers because……?
Your answer please in a paper of less than 5000 words that doesn’t take seven years to write.
tonyb
1975 and 1976 were both very hot and dry years, and resulted in very limited tree growth and thin tree rings in the UK. If temperature was a leading factor in tree ring growth, they would have been wider.
…………………Michael Mann says it is.
Mike, I think you could be a bit more tolerant: Keith Briffa has on various occasions been a bit of a doubter among ‘The Team’, i.e., he’s more of a real scientist, questioning things on the basis of his own research. Your comment attributes bad motivations to a person who we really don’t know, something that the AGW proponents do all the time. Let’s not!
I’ve long suspected that Briffa was actually a closet sceptic. I bet he had access to all the UEA emails.
Briffa in the emails asks a few hard questions of the others – he struck me as man who liked good science, had some doubts about how far advanced it all was … and likely just needed to make a living.
I don’t know any science but,two trees born same day,same year,
one in the middle of a field,one in the middle of the woods.tree in field,
short and fat,Tree in woods ,tall and thin.both with the same number of
rings. Are the rings the same thickness?
Alfred
1934 was one of the hottest years of the 20th century in the USA. The area where Mann took his samples was suffering from extreme drought in 1934. In Mann’s bristlecone reconstruction it shows up as a down spike. Was Mann actually recording rain and not temperature?
http://wattsupwiththat.com/2008/03/19/treemometers-or-rain-gauges/
http://climateaudit.org/2008/03/17/principal-components-and-tree-ring-networks/
I should have said:
Was Mann actually recording lack of rain and not temperature?
When they start turning on each other, the end is near…
Tree ring growth rate is limited by the least favourable parameter, be it temperature, moisture, sunlight, pests, soil pH, or whatever.
Tree rings might be usable as temperature proxies only if there were solid evidence that nothing else changed in the tree’s environment.
Otherwise we might find the proxy wandering off from the temperatures and we have to ‘hide the decline’ during the best periods of instrumental temperature records… or some such.
The settle science meme is starting to look a teensy bit unsettled. The smell of Napalm in the morning …
Pointman
How long before a Mann e-mail forces a retraction and a statement of blind and unquestioning faith in ‘the cause ‘ ?
climatereason says:
June 17, 2013 at 12:54 am
Help me out here someone. Tree rings are believed to be reliable regional thermometers because……?
===========
no,no,no. tree rings are believed to be reliable global thermometers. the way they know this is because they select only those trees who’s rings match global temperatures in a process known in climate science as “calibration” and known in statistics as “selection on the dependent variable”.
And while “selection on the dependent variable” is forbidden in statistics, because it leads to false and misleading conclusions, in climate science it has proven a positive boon and had been universally accepted after it was first introduced by a mathematician. and who better than a mathematicians to know how to lie with statistics.
If there was any field of science searching for false and misleading conclusions, it was climate science. The beauty of the technique is that intuitively it seems correct, and thus fools the majority of people. If you want to know if medicine A is effective, study people that take medicine A. 97% of people that take Dr Ferble’s tonic get better within 2 weeks. What Ferble isn’t telling you is that 100% of people that don’t take the tonic get better in 1 week.
What the calibrated tree rings are telling us is that temperatures are going up due to AGW. What the other tree rings are telling us is that tree rings are not good thermometers, that some trees will match thermometers simply by chance, and that any conclusions made on this basis are likely to be false and misleading.
http://www.nyu.edu/classes/nbeck/q2/geddes.pdf
Peter Hannan says:
June 17, 2013 at 1:29 am
“Mike, I think you could be a bit more tolerant: Keith Briffa has on various occasions been a bit of a doubter among ‘The Team’, i.e., he’s more of a real scientist, questioning things on the basis of his own research.”
I agree. Indeed, I think we should encourage identification of the (very) few among the main players of the last couple of decades that showed resistance to the “consensus”. They were not strong psychologically perhaps, under the threat of exclusion and its downside, but they have kept afloat. Phil Jones first voiced the 15yrs without warming but then he re-jigged the temp record called Hadcrut 4.
Gary Pearse says:
June 17, 2013 at 6:47 am
Phil Jones first voiced the 15yrs without warming but then he re-jigged the temp record called Hadcrut 4.
============
Temperatures in the past are decreasing due to AGW. Ever year that passes, the past gets colder and colder because CO2 levels are lower in the past. This process will continue, even if Jones has to redefine the meaning of absolute zero.
ferd berple says :
Temperatures in the past are decreasing due to AGW. Ever year that passes, the past gets colder and colder because CO2 levels are lower in the past. This process will continue, even if Jones has to redefine the meaning of absolute zero.
The team says: The models prove the earth is getting warmer. The places where we can measure the temperature are not getting warmer, therefore the missing heat is located where the thermometers aren’t. The heat is in the deep ocean. Deep oceans have gotten much warmer in the last 20 years.
The apparent acceptance of circular reasoning in science is a gigantic step backwards for western civilization.
climatereason says:
June 17, 2013 at 12:54 am
But the simple answer is – they aren’t good proxies.
The central tenet of tree rings as proxies is based on the assumption that all things (except temperature) remain constant. Which we all know is complete BS from personal experience (at least if you are over say 20 years old! – as we have all seen some warm and cold seasonal variation).
The other point is that in order to have such a proxy as valid – there has to be some kind of general consistency in the proxy you are measuring. So, for example, with tree rings, if we have easily identifiable zones of ‘consistent’ growth – we can then say that something changed when this consistency was broken. The crux of the matter then becomes – what changed? water, co2, ph, etc, etc. As in a lot of this proxy stuff, a few zillion assumptions are made!
With enough creative mathematics and enough cash from a host of government grants, surely the Lord of the Rings can find the true climate signal in there somewhere.
When you let the data lead you, you go remarkable places. Briffa seems to be finding that out.
The hockey stick is baroquen.
Briffa should have done this work about ten years ago. This has the appearance of a much belated attempt to retrieve his reputation from the trash heap. I do not sympathize with Briffa and others who belatedly realize that the global warming scam is not going to work and then try to salvage their scientific reputation. They chose years ago and now are trying to undo their mistakes. Do not forget, this Briffa has fought FOI and data requests tooth and nail, only to lose, and now that the ugly truth about his methods are exposed he wants to get right with decent science. Piss on him, we don’t need him.
This Briffa gripe is actually quite important. Two things: Mann really is a hack ‘scientist’ but a great self-promoter and grant vacuum. Mann’s value to real scientists is PR and rainmaking grants. But there comes a point where Mann’s abusive manipulation of real scientists’ work is too much, and maybe, Mann’s money highway is slowing down. If Mann’s not sharing the wealth, scientists like Briffa have no reluctance to dump on him, IMO. So this is very signifigant.
also, concerning tree rings, they do not serve as temperature proxies, period. The whole pretense of Holocene temperature reconstructions via tree rings has been refuted variously and repeatedly.
It’s simple, Briffa wants to be part of the PFJ.
climatereason says:
June 17, 2013 at 12:54 am
Help me out here someone. Tree rings are believed to be reliable regional thermometers because……?
———————————
Because each tree gives a completely different result meaning that; whatever the results from climate model hind-casting are, they can be proven to be correct.
I don’t pretend to understand all the issues, but I don’t think readers should infer that Briffa et al. (2013) DID overtly condemn Mannian and IPCC-embraced reconstructions.
As I read it Steve M. is arguing that IF the technical basis for Briffa exclusions can be properly understood in scientific and statistical standards (I.e., not as merely another ad hoc gesture of convenience from The Team), THEN it will be realized (not yet, but soon) by honest scientists that the implied standards will have dramatic effects upon many other dendro reconstructions. See this exchange between Ross M. and Steve M.:
http://climateaudit.org/2013/06/16/briffa-condemns-mann-reconstructions/#comment-423280
Tree Rings
Older but funny video with Michael Mann.
Placing the Ross and Steve comments directly into this thread if mods permit, because I think it makes the whole issue more intelligible for this thread, too (link in my comment above):
As mpainter observed, Briffa refused for years to provide data and fought FOI requests. I’m told that Briffa also encouraged other dendros not to provide data. Briffa has a lot riding on the big HS of his Yamal chronology. Although this data has been used for years, this is the first article that even begins to provide technical information. It is at least 10 years overdue.
Skiphill’s observations are exactly right.
There’s no way that CRU would have “overtly” criticized the Mann reconstructions. Nor do I believe that they fully understood the implications of their standards on the Mann reconstructions. My point is that these standards are,as Ross put it, the “nuclear option” for bristlecone pine chronologies.
However, I also believe that hypocrisy within the field is so deeply rooted (so to speak) that Briffa and others will simply ignore the implication.
DesertYote says:
June 17, 2013 at 8:11 am
The hockey stick is baroquen.
================================
New keyboard, please. And a tissue to wipe the monitor.
“One Tree to rule them all, One Tree to find them,
One Tree to bring them all, and in the IPCC bind them,
In the land of Peer Review, where the Shadows lie.”
🙂 So very true!
Now that’s funny right there. Thread Winner!
Briffa Condemns Mann Reconstruction
Pot to kettle
DesertYote says:
June 17, 2013 at 8:11 am
The hockey stick is baroquen.
================================
Yep … Briffa kept the blade and gave Mann the shaft.
Alfred Alexander says:
June 17, 2013 at 3:14 am
I don’t know any science but,two trees born same day,same year,
one in the middle of a field,one in the middle of the woods.tree in field,
short and fat,Tree in woods ,tall and thin.both with the same number of
rings. Are the rings the same thickness?
Alfred
It isn’t ring thickness per se, but the pattern in which that thickness varies from year to year. Some years one tree or the other may actually drop a ring due to poor growing conditions. These patterns are highly reliable for determining the date a tree was felled, IF you have a piece with the outer layers intact. It can also date the age of a particular chunk of wood, if there are enough ring segments present to conduct pattern matching.
Tree rings do respond to local growing conditions and changes in them, which creates the patterns. That means that you need to have local tree ring sequences to employ for pattern matching. Trying to relate a polar larch from northern Russia to a strip-bark Bristle cone from the US could entail some real problems. If you are looking for “global” patterns in climate changes, then hypothesizing that global patterns will be superimposed on local trends in discernible fashion is logical. The problem then comes down to separating signal and “noise.” Signal would be global trends while noise becomes the local influences. Therein lies the devil.
This is a good time to remember what Briffa said in the freedom of information emails:
Briffa:
“I know there is pressure to present a nice tidy story as regards ‘apparent unprecedented warming in a thousand years or more in the proxy data’ but in reality the situation is not quite so simple. We don’t have a lot of proxies that come right up to date and those that do (at least a significant number of tree proxies ) some unexpected changes in response that do not match the recent warming. I do not think it wise that this issue be ignored in the chapter. For the record, I do believe that the proxy data do show unusually warm conditions in recent decades. I am not sure that this unusual warming is so clear in the summer responsive data. I believe that the recent warmth was probably matched about 1000 years ago. I do not believe that global mean annual temperatures have simply cooled progressively over thousands of years as Mike appears to and I contend that that there is strong evidence for major changes in climate over the Holocene (not Milankovich) that require explanation and that could represent part of the current or future background variability of our climate. ”
Maybe Briffa is following the following sage advice of John Maynard Keynes:
When the facts change, I change my mind. What do you do, sir?
NK says @ June 17, 2013 at 8:44 am
This Briffa gripe is actually quite important. Two things: Mann really is a hack ‘scientist’ but a great self-promoter and grant vacuum.
======================================================
CALLING MANN A HACK IS AN AFFRONT TO A NOBEL PRIZE WINNING SCIENTIST!
…or at least Mann saw somebody get a Nobel…
…or at least Mann knows somebody who knows somebody who got a Nobel…
…or Mann knows somebody (besides himself) who said Mann won a Nobel…
…at least Mann didn’t steal his self-generated Nobel prize certificate (a la Peter Gleick); upon further review, maybe he did…
Ok; Occam’s razor says Mann’s a hack.
.
NK says (June 17, 2013 at 8:44 am): “If Mann’s not sharing the wealth, scientists like Briffa have no reluctance to dump on him, IMO. So this is very signifigant.”
I won’t believe Briffa has actually bitch-slapped Mann until Dana Nuccitelli calls Briffa the D-word.
Skiphil quotes Ross McKitrick June 17, 2013 at 9:50 am
It was not only Mann who got away with using Mia Tiljander’s data upside down:
http://wattsupwiththat.com/2011/06/22/manns-inverted-tiljander-data-survives-another-round-of-peer-review/
I predict that neither science’s, nor Keith Briffa’s public reputation will suffer one iota from this.
Steve McIntyre says: June 17, 2013 at 9:59 am
“However, I also believe that hypocrisy within the field is so deeply rooted (so to speak) that Briffa and others will simply ignore the implication.”
//////////////////////////////
Cynical, but that is the point. Don’t expect withdrawals or revissions anytime soon.
Hal Javert says: June 17, 2013 at 1:36 pm
======================================================
CALLING MANN A HACK IS AN AFFRONT TO A NOBEL PRIZE WINNING SCIENTIST!
////////////////////////////////
Mann a nobel prize winning scientist is a conflation which gives the impression that Mann was awarded a Nobel Science award, which of course, he was not.
Some may argue whether Mann is a scientist; we all have our own personal views on this and scientific integrety. Leaving that issue aside,, at a strech, Mann can be considered a recipient of the Nobel Peace prize. In a way this is quite fitting since recent recipients of this prize have much blood on their hands having been instigators of wars and terrorism, or otherwise engaged directly or indirectly in the furtherance of such.
Regrettably, today, it appears that one of the criteria for awarding this Nobel honour is that the recipient must have been heavily engaged in dishing out human suffering. Bearing in mind the misery that is being wrought on the world and on human kind by CAGW (I have little doubt that deaths through starvation, high food prices and high fuel prices have occurred), Mann would appear to have contributed towards fulfilling the required criteria.
Osculating Mann’s fundament is too much for even some Team members! Amazing.
Unless we get a noticeable decline in global temperatures. It’ll be fun to see them sweat then, once they realize the warm has turned.
Mann: Lard of the rings.
The cynic in me wonders if the timing of this report has anything at all to do with this article from The Independent (via GWPF) http://www.thegwpf.org/britains-bad-science-scandal-uk-research-position-threatened-fact-fabricators/
“Britain’s leading science institutions will be told on Monday that they will be stripped of many millions of pounds in research grants if they employ rogue researchers who fake the results of experiments, The Independent has learnt.”
{ GlynnMhor says:
June 17, 2013 at 5:36 am
Tree ring growth rate is limited by the least favourable parameter, be it temperature, moisture, sunlight, pests, soil pH, or whatever. }
Generally speaking yes. However, the growth response is 3x for water. The reduction (increase) in response to 1 inch of water is 3x the response to 1 degree temp swing, and the temperature response is only at the peripheral edges of the the bell shaped curve.
Completely agree.
His Yamal hockey stick was just as egregious as Mann’s, and he defended it vigorously.
If he publicly denounces his previous, obviously erroneous, work, then maybe he deserves to be cut some slack.
Tilo Reber says:
June 17, 2013 at 1:06 pm
This is a good time to remember what Briffa said in the freedom of information emails:
What’s more important to remember is that he wrote that in “private”, and has not stated it publicly. That’s his “sin”.
Briffa’s selective use of tree ring data just shows “When you’ve seen one, you’ve seen Yamal.”
climatereason asks at June 17, 2013 ,12:54 am why “Tree rings are believed to be reliable regional thermometers”.
The answer is in the principle known as Growing Degree Days. All else held equal, there is a very well understood and quite well quantified relationship between the length of time that a plant’s environment is above a threshold temperature and its growth. For most temperate plants, the threshold is about 50F. So if you take the minimum and maximum daily temperatures for the day, subtract 50 from each (if negative, go to zero) and average the result, you get the degrees for the day. For example, a day with a high of 70°F and a low of 54°F would contribute 12 GDDs.
Keep a cumulative total for the season and you get the Growing Degree Days so far. Daffodils bloom at about 110 GDD and dandelions at 140 GDD. Apple and cherry trees start to blossom at 300 GDD but goldenrod doesn’t bloom out until about 2200 GDD. Other lifecycle events including the weight that a tree puts on during the year are well correlated to GDD.
Okay, a couple of caveats to the algorithm above. Plants also have an upper threshold above which you stop getting incremental benefit. For most temperate plants, 86F is about right. So the real equation is:
sum ((Tmax -50 +Tmin – 50)/2)
where Tmax is [86F, measured max, 50F] and Tmin is the similarly constrained minimum daily temperature.
(I’m doing a poor job of explaining this. BeeCulture magazine did a much better job back in Feb 2002. You can find more technical sources but theirs was very well written.)
Second, yes this is a loose heuristic. Some days, the temperature will spike and a cumumlative instantaneous record would be very different from the two-point average. For agricultural purposes, we’re trying to get within a day or two, not predict the hour of blooming. The two-point average has proven very reliable.
So back to the original point. Yes, GDD is a good predictor of tree growth. All else held equal, yf average temperatures for a year are above average, you’ll get more GDD and wider tree rings. In colder years, you get narrower tree rings.
It’s that first assumption that presents the real challenge to paleo-reconstructions. I can make very reliable statements about GDD and growth over population averages of plants that I can observe today. I can control for or at least adjust for variables like precipitation changes or shading. We don’t have that prior knowledge about the conditions for fossil tree rings. Properly done, we could assume that precipitation and shade should average out over a large enough area but there just aren’t that many usable tree fossils to make those kinds of statistical statements.
To me, that means that tree ring trends are a clue about possible temperature trend but they are far from sufficient to make definitive statements.