Severinghaus and “Hide the Decline”
By Steve McIntyre
One of the very first contributions to realclimate was an FAQ from Jeff Severighaus on Dec 3, 2004. A year earlier, Severinghaus attempted (unsuccessfully) to get an explanation of the “divergence” problem from Mann and the rest of the Team. Severinghaus had become interested in the question following a presentation by Tom Karl of NOAA in which he had used a figure from Briffa and Osborn 2002, in which he wondered about the “flat” response of the tree ring proxies in the last half of the 20th century.
In nearly all defences of the deletion of the decline in spaghetti graphs that yield a rhetorical effect of coherence between the Briffa and other reconstructions in the last half of the 20th century, it’s been argued that the divergence problem was fully disclosed in a couple of 1998 Briffa articles and that this disclosure in the original technical literature constituted sufficient disclosure – a point that I contested long before Climategate.
The Severinghaus exchange is highly pertinent to this issue. Severinghaus was a climate scientist who was not a specialist in the area who asked specifically about a diagram in which the decline had been hidden (though Severinghaus was unaware that the decline had been hidden.)
Severinghaus was concerned merely by the flattening of proxy response. One can only imagine how the exchange would have read had Severinghaus been aware that the Briffa reconstruction actually declined sharply. Read and see whether Mann, Jones and/or Briffa drew Severinghaus’ attention to the early articles in which the divergence problem was disclose.
On the afternoon of Feb 1, 2003 California time (emails -2545, 19, 4355 Feb 2, 2003 00:15 GMT), Severinghaus wrote to Tom Karl of NOAA about his presentation at the MIT Global Change Forum the previous day. Severinghaus asked about the “flat” response of tree rings to late 20th century warmth, referring to an article by Briffa and Osborn in Science (2002). The diagram in question would be the following:
Figure 1. Briffa and Osborn (Science 2002) Figure 1.
Severinghaus observed that this lack of response is an “embarrassment” and that it “casts doubt on the integrity of the proxy”:
Subject: tree rings and late 20th century warming
Date: Sun, 2 Feb 2003 16:15:04 -0800
From: Jeff Severinghaus
to: Thomas.R.Karl
Dear Dr. Karl,
I enjoyed your presentation yesterday at the MIT Global Change forum. You may recall that I asked about the failure of tree rings to record the 20th century warming. Now that I look at my records, I realize that I remembered this wrongly: it is the LATE 20th century warming that the tree rings fail to record, and indeed, they do record the early 20th century warming.
If you look at the figure in the attached article in Science by Briffa and Osborn, you will note that tree-ring temperature reconstructions are flat from 1950 onward. I asked Mike Mann about this discrepancy at a meeting recently, and he said he didn’t have an explanation. It sounded like it is an embarrassment to the tree ring community that their indicator does not seem to be responding to the pronounced warming of the past 50 years. Ed Cook of the Lamont Tree-Ring Lab tells me that there is some speculation that stratospheric ozone depletion may have affected the trees, in which case the pre-1950 record is OK. But alternatively, he says it is possible that the trees have exceeded the linear part of their temperature-sensitive range, and they no longer are stimulated by temperature. In this case there is trouble for the paleo record. Kieth Briffa first documented this late 20th century loss of response.
Personally, I think that the tree ring records should be able to reproduce the instrumental record, as a first test of the validity of this proxy. To me it casts doubt on the integrity of this proxy that it fails this test.
Sincerely,
Jeff
Severinghaus obviously didn’t know that the Briffa and Osborn diagram had deleted the post-1960 decline from the Briffa reconstruction. Had they shown the actual data, the diagram would have looked more like the one shown below.
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OT: I just want to give a shout out to “Ray Ladbury” for helping to make me an AGW skeptic over the years I have been lurking at RC and WUWT. You’re doing a heck of a job, “punkin.”
The difference in tone between the two sites is so striking.
(Who is that guy anyway? Please tell me he’s not a scientist.)
If it doesn’t follow the measured temperature record it isn’t a proxy for temperature, end of story.
“But alternatively, he says it is possible that the trees have exceeded the linear part of their temperature-sensitive range, and they no longer are stimulated by temperature.”
Oh yes, this certainly is a reasonable theory…
how about…
“But alternatively, he says it is possible that CO2 has exceeded the linear part of its sensitive range, and CO2 no longer are stimulates temperature.”
Oh no, that is absolutely preposterous, it increases exponentially!!!
Uh huh…
/sarc
Tree rings are proxies for aggregate growth conditions, one of the items in that aggregate being temperature (and generally only temperature in a specific portion of the year, colder winter temperatures, for example, will generally not show up in tree rings). For example, we are now looking at the possibility that increased snow pack in the winter resulting in later melt off (delayed warming of the soil) possibly has a significant impact on tree ring growth so if you have a period of increased winter precipitation you might have reduced growth rates the summer air temperatures notwithstanding. CO2 itself can cause increased growth rates, too. Changes in the pH of the rain could impact the absorption of nutrients. Changes in cloud cover, changes in animal migration routes (nitrate availability from animal droppings), fires (small forest floor fires releasing nutrients) can play a role, etc. And the problem becomes even worse when a tree ring series is winnowed down to only a few trees and only these few used in the reconstruction. Were those the trees that a reindeer crapped next to? Did a neighboring tree in the immediate proximity of your selected tree die and fall over or lose a limb in a storm and allow more sunlight to reach the selected tree? It seems to me that the whole thing is smoke and mirrors if you are selecting only certain trees from a series to meet your criteria for inclusion in a representative sample as a temperature proxy. I want to know what the overall response has been for all of the trees sampled. I would expect that to filter out the noise from a tree falling over. I just don’t have a lot of faith in time series where the members are picked for response to “temperature” when that “temperature” record itself is possibly tainted.
Oh, hey, by the way, I was driving through the Inyo National Forest this summer South and East of Mono Lake on Highway 120 and apparently there was a fairly recent fire there. There are several rather large trees down and several of them cut into “chunks” and they might be good for collecting some ring samples.
Trees are a good indicator of temps, except when they are not, but they know when this happens and will fix everything for us laymen. Good thing we have climate scientists to point out when black is white for us.
I am always amazed when ostensibly intelligent people never say, “That doesn’t answer my question! In fact, you appear to feeding me crap!”
Why is that?
based on my understanding of tree rings as proxies for temperature the only way to use a tree ring size for a temperature is to calibrate tree rings against known local temperatures which would give you a rough conversion i.e. tree ring of x size = y temperature … this conversion value is arrived at by matching tree rings against know temperatures. In this case tree rings for the past 100 ish years are compared against local temperatures for the same time period and thus a conversion factor is calculated. In that case it should be impossible for tree rings to widely diverge from temperatures since the temperature gives us the proxy value of the tree ring. In fact the one period of time when tree ring “temperatures” simply should not diverge greatly from local measured temperatures is during these calibration years.
This all assumes that tree rings are in fact actual proxies for temperatures.
I suspect they ignored recent tree ring calibration values because when they included them all of their older tree ring proxies showed much higher temperatures and would have destroyed their meme of AGW and also would have shown tree rings to be useless proxies for temperature …
“he says it is possible that the trees have exceeded the linear part of their temperature-sensitive range, and they no longer are stimulated by temperature”,…………. but they are positive that this has only happened in recent times and never before in the past…….because our tree rings don’t show any warming in the past comparable to today………..
I learned at a young age it was impossible to lift a board off the ground while I was standing on it, but that kind of circular reasoning is the thing a great climate scientist is made of.
If just one tree that Briffa used – YAD061 – had been left out, the entire hockey stick shape would have been eliminated. Either Briffa knew that, or he is too ignorant to be employed in anything above manual labor.
I think he knew exactly what he was doing: cherry-picking proxies to create an alarming hockey stick shape, in order to generate grants. IMHO he is no different than the rest of the climate charlatans who suck up federal grant money based on this kind of deception.
Uhhgg!! The graphic is too large! The end, (the place pertinent to the post) is obscured by the WUWT facebook advert.
I should know this, but where is Severinghaus now? He must know about hide the decline, what does he say now?
A comment on Peilke the Elder’s posting (since his comments are turned off), I happened to notice this from Adrian Simmons.
Apparently the problems with ERA-40 were legion and not just in the Arctic. This is from a quoted portion of 5239.txt in conversation with Jones in Feb 2004.
If you are looking for a CO2 greenhouse signal, it should be seen in warmer minimum temperatures as a portion of the heat radiated from the surface into space at night would be re-radiated back to the surface from atmospheric CO2. What they seem to say here is that most of the changes (both up and down) seem to be in daytime highs, not nighttime lows.
@Tierney – Regarding Ray Ladbury, he has a doctorate in particle physics and works at NASA, if you can believe the NASA information page about him. After the beating I took at RC because I didn’t do the research myself, rather relying on “science-y” websites that have long been refuted (although no citations), I will take the credentials with a grain of salt. After all, I haven’t contacted either NASA or the university to “verify” the claims. Seriously, I don’t doubt them, but I found the environment at RC very stifling. I was labeled “arrogant or an idiot” (my choice!) and my arguments immature because I trotted out the old skeptic arguments and I needed to go back and “learn the science” because everyone knows that Svante Arrhenius proved CO2 will cause global warming 115 years ago. Well everyone except me because I’m an idiot.
By their own rules, shouldn’t any proxy record that diverges from the temperature record be discarded or at least weighted very low?
This piece suggests to me that the core Team had internalized belief, that the world was warming unusually in recent years, and that they were on the case, to such an extent that any evidence against this had to be hidden from the unwashed, their colleagues, and even from their own perception and memory.
I think we have a new piece of Team vocabulary to add to “hide the decline” and “crap“. I read Mann’s use of the word “discuss” in this way:
“discuss” a la Mann = distract, deny, obfuscate, blow smoke – thimblerig
“discuss time and again” a la Mann = relegate to “Censored” folder in both computer records and personal memory
You must understand that according to Mann, people who are vocal about their skepticism “are fundamentally dishonest in everything they do or say” 3399.txt Jan 2004.
So simply standing on one’s convictions, asking questions and demanding they be answered is “fundamentally dishonest”. Who knew?
Kaboom says: “If it doesn’t follow the measured temperature record it isn’t a proxy for temperature, end of story.”
If it follows the temperature record until the late 20th C then it might not be the end of the story . . . John L Daly’s comments as recently posted on here helped to put tree ring data into perspective but didn’t invalidate it. . . it might just be that tree ring data v temperature needs closer and more thorough investigation – especially in relation to the late 20th C. Sometimes the answer is right there in front of us and we can’t see it . . .
Given the choice between trusting trees or humans I’d go for the trees every time . . .
Until someone decides to prank Briffa and rent a small plane and a few bags of fertilizer …
Perhaps the whole issue is moot? An interesting e-mail highlighted over at junkscience.com …
http://junkscience.com/2011/11/27/climategate-2-0-wigley-quantifying-climate-sensitivity-cannot-be-done/
From the Climategate 2.0 collection, Tom Wigley e-mails Keith Briffa and Simon Tett (UK Met Office) and pretty much condemns the possibility of quantifying climate sensitivity (presumably to human forcing):
“Paleo data cannot inform us *directly* about how the climate sensitivity (as climate sensitivity is defined). Note the stressed word. The whole point here is that the text cannot afford to make statements that are manifestly incorrect. This is *not* mere pedantry. If you can tell me where or why the above statement is wrong, then please do so. Quantifying climate sensitivity from real world data cannot even be done using present-day data, including satellite data. If you think that one could do better with paleo data, then you’re fooling yourself. This is fine, but there is no need to try to fool others by making extravagant claims.” — http://foia2011.org/index.php?id=253
Eureka!
What I am seeing is a pretty typical “fundamentalist” response. So lets say one must believe that the earth is warming at an unnatural pace and that CO2 emitted by humans is the cause. Those are the fundamental beliefs. Anyone calling either of those two issues into question will be seen as attacking their belief, and since they have (as you say) internalized those beliefs, experience any such attack as a personal attack and it will get a “retaliatory” response.
Go into any fundamentalist forum of any sort and question the basic underlying foundation of their particular school of thought and you will be treated in much the same way. They will show you the literature but if you question that, you will be initially dismissed as “just not getting it” or “too dumb to understand” hoping that you will just go away but if you persist, you will be retaliated against. Now the response is quite different in private than it is in public. One thing a person who is on shaking ground wants to avoid is the notion that it is ok to question their fundamental beliefs. This is because if they have to pay attention to you in public, that might encourage others to speak up and heck, if they have to answer your FOIA request, then there might be a flood of other ones!
The reaction I see is one of fear. They are afraid of it being shown that their foundation has cracks in it and they want to discourage dissent in public. The notion that one does not criticize the team/culture/race/religion/country/family/party/tribe in front of outsiders is a pretty well-established pattern of human behavior. So their reaction is saying that they have, in their minds, become a tribe, probably without even realizing they have done so. These people would naturally assume that they are the ones who decide who the “real” climate scientists are (the ones who agree with them in public!). That even shows through in their PR website’s name (“real” climate).
I haven’t read the comments here yet – but duplicating a comment I left on the climate audit thread:
re:
The true irony here is that if this explanation were correct, it would also mean that the trees may have exceeded the linear part of their temperature-sensitive range gawd knows how many times or for what duration in the past also, and therefore failed to show us past temperature increases similar to or worse than that of the past half century.
In other words, this possible ‘explanation’ provided is completely illogical and serves to totally debunk the use of trees as temperature proxies altogether. The only way it can possibly explain the divergence while supporting the use of the proxy is if one uses circular logic and assumes that there was no similar temperature increase during the MWP or any local/regional warming out of cold snaps, etc., which “exceeded the linear part of their temperature sensitive range.” This rational would also imply that by definition the treemometers will provide one with a significantly flattened record that fails to actually follow significant temperature changes.
And unless I’m missing something, the ozone rational is just more flailing around also, since I don’t believe we have any calibrated proxies able to accurately show what the historical ozone cover was over the areas where the tree rings were collected during all of the years each of the applicable tree rings were formed.
It also strikes me yet again just how much these people – I can’t bring myself to call them scientists anymore – waste far more time complaining, rationalizing, scheming, claiming that ‘rotten’ science is so bad it doesn’t deserve a response (without ever saying how it’s supposedly ‘rotten’ of course) and so on, than it would take to just answer the questions, debunk the ‘bad’ science, or respond to FOI’s, etc. That sort of behavior of course begs the question of whether they are at all capable of responding with actual meaningful answers, refutations, or data as applicable.
the thing I have always wondered about tree rings is how are the widths of the rings measured. Is it done manually with calipers ? is it done using a microscope with a “yardstick” of some sort … How much “skill” is involved with these measurements and how much is dependent on the same person measuring every ring in a climate controlled environment … How big are the error bands of these measurements … since we are talking about very small sizes even a slight error would make a huge difference …
Does anyone publish their raw ring measurements ?
For JeffC:
http://web.utk.edu/~grissino/index.htm
I think winDendro was disscussed at CA a while back.
Severinghaus said: “Personally, I think that the tree ring records should be able to reproduce the instrumental record, as a first test of the validity of this proxy. To me it casts doubt on the integrity of this proxy that it fails this test.”
In other words, the whole idea of using tree rings as a proxy has apparently been falsified. I wonder if there have been any further tests of this proxy; it should be easy enough to do a proper double blind test today. I mean, we have loads of trees and instrumental temperature data galore.
I would be very surprised if the researcher got it right.
Perhaps “hide the decline” really means “hide the unfortunate falsification” …