Guest Post by Willis Eschenbach
The quote above is from Lord of the Rings, an exchange between Gollum and Smeagol, and it encapsulates my latest results from looking into the Shakun 2012 paper, “Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation” (paywalled, at Nature hereinafter Shakun2012). I discussed the paper in my post “Dr. Munchausen Explains Science By Proxy“. Please see that post for the underlying concepts and citations.
When I left off in that post of mine, I had investigated each of the 80 proxies used in Shakun2012. I plotted them all, and I compared them to the CO2 record used in their paper. I showed there was no way that the proxies could support the title of the paper. Figure 1 recaps that result, showing the difficulty of establishing whether CO2 leads or lags the warming.
Figure 1. All proxies (green dots) from Shakun2012 (Excel spreadsheet). CO2 values digitized from Shakun 2012 Figure 1a. There is pretty good agreement between the warming and the changes in CO2.
Note that the proxies say the earth generally warmed from the last ice age, starting somewhere about 15,000 BC, and the warming lasted until about 9,000 BC. Since then, the proxies have the greatest agreement (darkest green). They say that the globe generally cooled over the length of the Holocene, the current interglacial period since the last ice age.
Today I was thinking about that single record that they used for the CO2 changes. I got to wondering what other ice core CO2 records might show about the change in CO2. So I went and downloaded every ice core CO2 record that I could find that covered the time period 26,000 BC to modern times. I found a number of ice core records that cover the period.
Then I collated all of them in Excel, saved them as a CSV file, opened the file in R, and plotted every ice core CO2 record that covered the record from 26,000 BC up to the present. I standardized them over the same period covered by the Shakun2012 CO2 data. There was excellent agreement between the Shakun2012 data and the ice core records I had downloaded … but there was also a surprise.
Figure 2 shows the surprise …
Figure 2. As in Figure 1. Black circles show Shakun2012 CO2. Additional colored dots show the ice core CO2 records which have data from 26,000 BC to the present.
Dang, I didn’t expect that rise in CO2 that started about 6,000 BC. I do love climate science, it always surprises me … but the big surprise was not what the ice core records showed. It was what the Shakun2012 authors didn’t show.
I’m sure you can see just what those bad-boy scientists have done. Look how they have cut the modern end of the ice core CO2 record short, right at the time when CO2 started to rise again …
I leave the readers to consider the fact that for most of the Holocene, eight centuries millennia or so, half a dozen different ice core records say that CO2 levels were rising pretty fast by geological standards … and despite that, the temperatures have been dropping over the last eight millennia …
And I leave everyone to ponder how far climate “science” has fallen, that a tricksy study of this nature can be published in Nature, and can get touted around the world as being strong support for the AGW hypothesis. The only thing this study supports is the need for better peer review, and at a more basic level, better science education.
My best to all, stay skeptical,
w.
Source data:
ICE CORE CO2 DATA: All ice core CO2 data are from the NOAA Paleoclimatology site, the “Ice Core Gateway” page, in the section “Gases”.
[UPDATE] A hat tip to Jostein, in the comments he points out that the original Shakun Nature paper is here (pdf).
Volker,
what is the value of Pearson’s r for these two time series?
Since the plain intent of the CAGW politico-climate complex is to forge One Ring To Rule Us All, it’s very à propos.
Here’s the Shakun paper: “Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation”
http://sciences.blogs.liberation.fr/files/shakun-et-al.pdf
Eschenbach wrote:
“Finally, their claim is that the warming is “driven by increasing CO2 concentrations”. But the CO2 continues to increase, and the warming stops … which threatens their argument, as I said above.”
You may believe that this threatens their argument, but the increase in CO2 was only about 8%. If the climate sensitivity were 3C, as most climate scientists believe, and CO2 were the only driver, the change in temperature at equilibrium would be about 0.3C. This is 1/10 of the average global temperature change during the period studied in Shakun2012. Accounting for this era would be the subject of another paper, and would be much more challenging given the many small forcings that need to be taken into account, and the fragmentary data.
The change in orbital forcing are in the opposite direction and are probably responsible for driving a good part of the decrease in temperature.
http://upload.wikimedia.org/wikipedia/commons/b/bf/Orbital_variation.svg
In fact this era has been well covered by others, and lack of inclusion is not a defect of the Shakun2012 paper:
http://www.meteo.psu.edu/~mann/shared/articles/Schmidtetal-QSR04.pdf
“The principle forcings are orbital, solar, volcanic and events
(such as the 8.2 kyr BP event). Land use and greenhouse gases also play a small role.”
wilt says:
April 8, 2012 at 11:42 am
No, they’re the same graphs. It’s hard to see in the abstract. But if you click on one of the graphs and then zoom in on it (in Safari it’s command – “+” on the Mac, dunno what key combo zooms in on the PC) you can see that in all cases the furthest right number on the years scale is “8”, for eight thousand years before present (1950). Then there’s one tick mark and about half a unit to the end of the graph.
All of the graphs, in other words, end at about 6,500 years before the present (BP).
w.
This is a prime example of why the internet should not be subject to political control or to control by the UN or any other international agency. The internet, among other things, provides the opportunity for scientific review and promotes discussion where there would otherwise be none.
“If the climate sensitivity were 3C, as most climate
scientistsalarmists believe…”There. Fixed it for you.
IPCC’s 3ºC model vs reality.
[blockquote]Lincoln Sparrow says:
April 8, 2012 at 9:36 am
Summary: The paleoclimate analyses of WUWT/Willis Eschenbach and James Hansen are rapidly converging toward a consensus that AGW is real, serious, and destined to accelerate in coming decades.
Kudos therefore go to WUWT, Willis Eschenbach, and James Hansen![/blockquote]
Appears “A.Physicist” is being channeled ….
[Note: “Lincoln Sparrow” is the same poster as “R Kcin” and “Marcella Twixt”. ~dbs, mod.]
Many people here misunderstand Hide the decline.
The issue had to do with more than not showing data. It had to do with actually removing data from archives.
Let’s use another example: In Fall et al Anthony and company looked at 1979 to present.
When Berkeley released a preprint that looked at 1950 to present, many people jumped all over that decision. maybe for good reason. maybe not.
The authors here set out to make a case about a particular time period. They are not hiding any data or removing it from archives ( as in hide the decline) The extra data is out there for somebody who wants to make a different case about different time periods.
The bottomline is that nothing you can find in proxies will ever be strong enough evidence to reverse known physics. GHGs increase and, all other things being equal, temperature will increase.
When you find periods where the two ( GHGs and temp) do not move in concert, you know one thing: all other things were not equal. You don’t know and you can’t know that GHGs dont increase warming. You dont and cant because fundamental physics is correct. We known that its correct because we building working devices based on that physics.
Smokey says:
April 8, 2012 at 12:23 pm
Eric Adler says:
April 8, 2012 at 9:53 am
“Willis Eshenbach…
“Your comment has no bearing on the validity of the paper you are trying so hard to impugn.”
As his ^comment^ makes clear, Eric Adler has zero understanding of the scientific method. It is the duty of scientific skeptics to tear down conjectures whenever they can. Willis has done an excellent job of deconstructing Shakun et al.”
It is clear that you have zero capability of dealing with the point that I made, and neither you nor Willis Eschenbach has answered it.
“Shakun is just pulling a Michael Mann trick, using carefully cherry-picked proxies to arrive at a conclusion at odds with the mountain of evidence showing that a rising temperature results in rising CO2, just like a warming Coke outgases CO2.”
Shakun has certainly not cherry picked. He used 80 proxies covering all regions of the globe. Willis has not made that charge because he obviously knows better.
You should cut down on the number your trollish posts and do some real thinking for a change.
Jostein: Here’s the Shakun paper: “Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation”
Thank you.
Steven Mosher says:
“GHGs increase and, all other things being equal, temperature will increase.”
Allow me to restate that correctly:
Ocean temperatures increase, and all other things being equal, CO2 will increase.
Steven Mosher: GHGs increase and, all other things being equal, temperature will increase.
Ah. I see that now you add “other things being equal”. Now all you have to show is that it is possible to tell when all other things are equal, have been equal, and will be equal.
Willis, thank you very much for clarifying the question whether the graphs shown with the Abstract are different from the “real” ones in Shakun’s paper. I had zoomed in to some extent and by mistake thought (as Chris V perhaps did as well) that the furthest right number was 0 instead of 8.
So you have convinced me now that Shakun left out all the recent data from 6,500 years before the present. I am still not sure that this was done deliberately, but the authors surely would have done the decent thing by showing ALL the relevant data (and then explain why the CO2-temperature relationship would be different in recent times).
Jostein says:
April 8, 2012 at 12:48 pm
Many thanks, Jostein, I’ve added this to the head posts of this and my previous post, and given you credit.
w.
Willis graph of CO2 seems to me to be the same as the one in IPCC, AR4 chapter 6, p 448, fig 6.4. In the AR4 report we can se that the level of CO2 is increasing from about 6000 years ago.
“Man_Tran says:
April 8, 2012 at 8:36 am
As a dynamicist, I was intrigued by the ‘high frequency’ transient in some of the proxy data that has a positive peak around -12k yrs and a negative peak around -10k years. I would love to see someone correlate that with other events during that era”
The 10Be record from GISP2 ice and from the Taylor dome give the same line-shape. Of course, we all know that solar output, cosmic ray levels and Stella dust can have no impact on temperature or atmospheric CO2.
Eric Adler says:
“Shakun has certainly not cherry picked.”
Then what would you call Shakun’s carefully selected time line? A simple mistake? Read wilt’s comment above.
Willis, will you be invited to ICCC-7 ? I am one of those amature geeks that watches the heartland streaming of the event. I would love to see this as a presentation, and some of your other climate investigations.
The graphics are tiny on the abstract page – and as Willis notes people are not seeing what they actually show. Another member posted this link:
http://i39.tinypic.com/f0qkcw.jpg
Which shows – by scale at bottom – that the record is truncated at point they stop reporting CO2 appx 6500 years BP.
And Willis – it is “CTRL” and “+” (or “-“) to zoom in the PC world
Willis,
To avoid being accused by alarmists of truncation of data, modern CO2 levels and temperatures might be overlaid. I’m sure someone will do it. To make it real, other CO2 proxies should also be shown.
Steven Mosher says:
April 8, 2012 at 12:59 pm
Good to hear from you. You are correct when you say that the authors are talking about “a particular time period”. My point is that that specific time period was very carefully chosen.
Again you are 100% correct that all things being equal temperature will increase. But the climate actively adapts and responds to changes, so things are never equal. If temperatures change, cloud patterns change. Ocean currents change. Tropical cirrus forms earlier. We get more El Ninos. And the balance is maintained. The amazing stability of the planetary temperature is the result of those and dozens of other homeostatic and thermostatic mechanisms.
Look at Figure 1. The median rise shown there is about 4°C from the low point around 16,000 BC to the high point around 8,000 BC. Which means that over the last ten thousand years, the globe has cooled by around a degree. For a heat engine which throws away about 30% of the incoming energy (albedo reflections) that is governed by something as insubstantial as clouds, that is astounding stability.
Since in natural flow systems all other things are never equal, this statement doesn’t mean anything.
I see the problem. You are conflate two separate ideas. They are:
1. GHGs cause increased forcing.
2. Increased forcing causes increased warming.
The first statement is fundamental physics and is undoubtedly true.
The second statement, as you point out, is only true if other things are equal … but other things are never equal. So it is not “fundamental physics” by any stretch of the imagination.
w.
major9985 says: “Why dont you average the proxy temperature records Willis?”
Averaging data does not create information; it destroys it.
Almost all the proxies are coastal, implying milder climates compared to the interior. And of course low elevation.
Is there any difference if you just use non-coastal proxies?
Willis, you may have missed Pat Frank’s comment at April 8, 2012 at 2:38 am. Thought he made some excellent points. My own view is that Shakun’s thesis has a single thrust, which is typical of graduate theses, but NATURE should have a broader view and so their editorial policy should instill some context, but evidently they do not.