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).
Most of the time period covered here is like the previous nearly 400,000
years, where few warmists heavily dispute CO2 lagging temperature. During
that time, the total of atmospheric, hydrospheric and biospheric carbon was
constant, and atmospheric CO2 content was one of the positive feedbacks.
But once humans started transfering carbon from the lithosphere to the
atmosphere, increase of CO2 became a cause of warming. It appears to me
that the debate should be over how much or how little, rather than whether it
does or does not.
I have done research of my own, leading me to findings of modern global
climate sensitivity ranging from .67 to 1.5 degree C/K per factor-of-2 change
of CO2, and decreasing as global temperature and greenhouse gas
presence increase. This is much less than figures advocated by most
advocates of existence of manmade global warming via CO2.
But before I got that far, I handled debate as to whether CO2 was higher
during WWII than now, whether nature has recently been adding or removing
CO2, and cherrypicked 10, 11, etc. year parts of global temperature record
beginning with a century class El Nino and ending with a La Nina. When the
debate I handled was along those lines, I thought that manmade CO2 causing
global warming meant causing *as much* warming as advocated by most
advocates of manmade CO2-caused global warming.
I like the way that. around -11000, there is a sharp dip in the temperatures and the CO2 responds! I think Shakun must be a’shakun’ that he has been rumbled.
Seriously, when do these people stop trying to support this edifice of delusion and illusion.
LOL
Great find and interesting post Willis! Thanks, William.
The Greenland Ice sheet temperature data and record of CO2 supports your finding and posting. CO2 rises throughout the 6000 year period while temperatures drift down. The ice sheet data also shows the Dansgaard/Oeschger cycles (also referred to as Bond Cycles) which are cycles of warming and cooling. Obviously CO2 does not cause Dansgaard/Oeschger cycles of warming and cooling. Bond noted in his published research that the cycles have a 1500 year period and that there are concurrent cosmogenic isotope changes that occur at the same time as the warming and cooling.
The 20th century warming appears to be a Dansgaard/Oeschger cycle as it correlates with a large solar magnetic cycle change.
http://climate4you.com/images/GISP2%20TemperatureSince10700%20BP%20with%20CO2%20from%20EPICA%20DomeC.gif
http://climate4you.com/
Fig.3. The upper panel shows the air temperature at the summit of the Greenland Ice Sheet, reconstructed by Alley (2000) from GISP2 ice core data. The time scale shows years before modern time, which is shown at the right hand side of the diagram. The rapid temperature rise to the left indicate the final part of the even more pronounced temperature increase following the last ice age. The temperature scale at the right hand side of the upper panel suggests a very approximate comparison with the global average temperature (see comment below). The GISP2 record ends around 1855, and the red dotted line indicate the approximate temperature increase since then. The small reddish bar in the lower right indicate the extension of the longest global temperature record (since 1850), based on meteorological observations (HadCRUT3). The lower panel shows the past atmospheric CO2 content, as found from the EPICA Dome C Ice Core in the Antarctic (Monnin et al. 2004). The Dome C atmospheric CO2 record ends in the year 1777.
The past temperature changes show little (if any) relation to the past atmospheric CO2 content as shown in the lower panel of figure 3. Initially, until around 7000 yr before now, temperatures generally increase, even though the amount of atmospheric CO2 decreases. For the last 7000 years the temperature generally has been decreasing, even though the CO2 record now display an increasing trend. Neither is any of the marked 950-1000 year periodic temperature peaks associated with a corresponding CO2 increase. The general concentration of CO2 is low, wherefore the theoretical temperature response to changes in CO2 should be more pronounced than at higher concentrations, as the CO2 forcing on temperature is decreasing logarithmic with concentration. Nevertheless, no net effect of CO2 on temperature can be identified from the above diagram, and it is therefore obvious that significant climatic changes can occur without being controlled by atmospheric CO2. Other phenomena than atmospheric CO2 must have had the main control on global temperature for the last 11,000 years.
Willis: I’d add my voice to getting someone on board with you, perhaps Dr. Spencer or someone like that, and condense this down and send it to Nature. The odds are that Nature will not accept it, but the act of getting it polished and condensed for submission will improve it and make it more powerful.
Willis, all your postings are excellent and the last two are no exceptions. This last one I doooo like as it does not leave much room, if any, for the idea that a doubling of CO2 can, will or does contribute to “maybe” 1 °C of atmospheric warming (biased little me).
Looks like you may be one of those “heretics” who are giving skeptics like Fred Singer a bad name, however it may just be true that a wise person waits until all the “available evidence” has been analysed before he (or she) apportions blame.
It appears to me that the debate should be over how much or how little, rather than whether it does or does not.
Anthony would agree. So would Lindzen. Monckton, too, for that matter. The real debate centers around feedbacks.
One will note that the actual instrumental record is being called into considerable question. it is possible that 20th warming, itself, is exaggerated (perhaps by a factor of two).
I handled debate as to whether CO2 was higher during WWII than now,
It once seemed to me that it must have been higher. Industry was going full guns (“Spare Gas fur Rusting”) and a hundred major cities were incinerated or blasted to bits. But OTOH a lot of the oil and coalfields were in the combat zone, and a lot of the labor force was at the front. Proxy records show a slight CO2 drop during the height of the war as compared with 1940. After all, I’m not sure i know what to think.
In re …
wmconnolley says:
April 8, 2012 at 12:48 am
*******
There have been two quite juvenile responses to wmconnelley’s link and its contents.
Perhaps a more mature comparison and analysis of his views with those of Willis would be useful … particularly to those of us who are not scientifically-inclined.
Many thanks.
Pedro
Willis is simply not showing you that the Southern Hemisphere warmed first, while the Northern Hemisphere slowly caught up over 8000 years.. This is why he says the proxy records are all over the place and he shows them all together http://wattsupwiththat.files.wordpress.com/2012/04/nature_shakun_proxies_plus_co2.jpg
When you average out all the Northern Hemisphere Proxy’s and compare them to the Southern Hemisphere Proxy’s as shown in this graph http://i44.tinypic.com/34gncox.jpg you can see why some of the proxy’s have a late warming start. These proxy’s are not cherry picked, it is just the simple fact that the Hemisphere’s warmed at different times and the proxy’s show that. Here is a graph of all the proxy sites used to get a global temperature average http://i41.tinypic.com/1432dtw.jpg
If you average out all the proxy records to get a global average you can very easily see that temperatures trail CO2 http://i39.tinypic.com/f0qkcw.jpg and as you can see (because the proxys have been averaged in the graph, not like Willis) temperatures keep on going up as CO2 levels off. This temperature/CO2 division is miniscule and is easily seen on any Holocene temperature/CO2 graph http://www.geocraft.com/WVFossils/PageMill_Images/image357_lg.gif even when compared to multiple temperature records, the Holocene is flat in line with CO2 http://ossfoundation.us/projects/environment/global-warming/myths/images/temperature-records/Holocene_Temperature_Variations_Rev.png
Am I missing something here? The graphs from Shakun’s paper that are included with the abstract all show CO2 levels up to the present:
http://www.nature.com/nature/journal/v484/n7392/full/nature10915.html
“Climate sensitivity is not constrained by the last two decades of imperfect satellite data, but rather the paleoclimate record.”
NASA climatologist Gavin Schmidt
Well Willis, you have estimates of [CO2] and ‘global’ temperature estimates. A plot of Ln([CO2]) vs Temperature will give you a slope, with error-bars in two dimensions, that will give you the ‘climate sensitivity’.
Of course, on will find that CO2 is not directly coupled to temperature, and the directionality of temperature change give two estimates of ‘climate sensitivity’.
Congratulations to WUWT/Willis Eschenbach for providing the raw material for *TWO* articles!
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Part I: WUWT/Eschenbach verify
the deglaciation CO2/temperature relations of Shakun2012
In a reanalysis of the data used by Shakun et al. in their “Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation” (Nature, 2012), WUWT/Eisenbach have affirmed the main conclusion of Shakun et al:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Part II: WUWT/Eschenbach verify
the CO2/temperature “Hockey Stick” of Mann1999
Extending the data used by Shakun et al. in their “Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation” (Nature, 2012) to encompass the anthropocene era 5000BP–present, WUWT/Eisenbach have affirmed the main features of the CO2/temperature “Hockey Stick” of Mann et al: in “Global-scale temperature patterns and climate forcing over the past six centuries” (Nature, 1999):
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
But Willis, to see this clearly, your data plots have to include *all* the temperature proxies, and *all* the CO2 data, for the *complete* period 5000BP–present. Because if you’re going to criticize Shakun et al. for not showing all their data, and for truncating their time series arbitrarily, aren’t you thereby obligated to show all of *YOUR* data?
To phrase this same point positively, Willis … you’ve already done a terrific service to both the skeptical and the scientific communities, by verifying the good analysis that Shakun et a: made of CO2/temperature relations during the last deglaciation (22000BP–6000BP), during which time the “main event” was the melting of the glaciers. Now you have a fine opportunity to repeat that analysis for the period (600BP–present), during which time the “main event” is the “hockey stick” of CO2/temperature.
This analysis, affirming both the mutual forcing of CO2 and temperature, and the reality of the 20th-21st century “Hockey Stick” in both quantities, would go far toward building a bridge of mutual appreciation and trust between skeptics and scientists— from which our entire planet would benefit.
So go for it, WUWT/Willis! Assure us that forcing is real, and so is Mann’s Hockey Stick!
Lincoln,
I’ve done what you are asking Willis to do. Read http://www.kidswincom.net/climate.pdf with an open mind and objectively come to your own conclusions.
Willis, the sheer time and effort you put into every single one of your posts is astounding. Highly informative, and above all; follows the classical scientific method.
Your work is highly appreciated and readable. Thank you.
Nice work Willis, but can I suggest (even on Easter Sunday) that if you do send this as a comment to Nature that you use BP (i.e. calibrated years pre-1950) rather than BC, and you explicitly note which of the calibration data sets this is based on (i.e. was it IntCal04 or IntCal09?), and how this influences results. IntCal09 tends to give somewhat older pre-Holocene ages than IntCal04.
Something tells me the Holocene CO2 concentration increase has been successfully dealt with in other papers. If nothing else, there’s ongoing change of Earth orbital parameters and the change in CO2 concentrations was several orders of magnitude slower than the change we’re usually discussing now, it can’t be told how exactly would it look like if the CO2 concentration didn’t increase over the Holocene. Maybe we’d be deep in another ice age already without it? I can’t really tell, but this is what I found discussing the matter:
http://ruby.fgcu.edu/courses/twimberley/EnviroPhilo/Steig.pdf
“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.”
Since Rio+20 is coming up soon, I’m expecting a lot more of these types of peer reviewed reports in the coming months. I wouldn’t be surprised to see some of their now discredited wild claims come back to life in new reports and papers.
It looks like:
for that data to see that no fit is resolvable from a zero-trend straight line.
a) The CO_2 “rise” it shows starting at 20 Kya is utterly spurious. CO_2 was utterly flat (to falling a little) from 25 Kya to 15 Kya. I don’t need to compute
b) As always, the Younger Dryas has much to tell us. If CO_2 is responsible for the warming trend in a positive feedback cycle, then it should have pulled the temperatures up across the YD instead of following the temperature curve down. Although as noted it looks like the YD signal is very attenuated in much of the coastal tropical data and is prominent only in the Antarctic cores. The CO_2 looks like it follows the tropical (much subdued) signal.
c) The Holocene Optimum was an easy 0.5 K warmer than today. Since then, the mean temperature has steadily dropped, while CO_2 has increased with a clear crossover. Conclusion: CO_2 variation isn’t a highly sensitive driver, or the main driver, of global temperatures. Secondary conclusion: Something else is!
While I am happy to believe that the bistable oscillations observed over the last half million or more years are coupled to astronomical cycles, that does not suffice to explain the bistability. There is a causal factor missing. I don’t think it is closing off of circulation patterns in the ocean because the effect isn’t sufficiently discrete for that (on the 5 million year scale). The temperature doesn’t plunge down, it very steadily drops. This is a knob being turned, not a door being slammed shut. Furthermore it is a knob that has been turned before, back when today’s continents were a distant event in the future. It’s not inconceivable that ice ages are caused by continental drift but the data makes it somewhat implausible.
It would be very, very interesting to look at Mars or Europa or any other planet with an accessible thermal history to see if there is evidence of Martian heating and cooling on the billion year timescale that matches that of the Earth’s. That would be direct evidence that the Sun itself is very long period variable in some way that might explain it. Perhaps it is connected with times that the solar system drifts through interstellar dust clouds and the sun is slowly “fed” with infalling matter, and when it drifts out the sun returns to a slightly cooler steady state.
But even that wouldn’t fully explain the bistability.
rgb
says:
April 8, 2012 at 7:17 am
In re …
wmconnolley says:
April 8, 2012 at 12:48 am
*******
There have been two quite juvenile responses to wmconnelley’s link and its contents.
Pedro~ We are speaking of a person who has distorted the biographies of many skeptic scientists, to smear their reputations and their efforts in climate science.
We are speaking of a person who has made changes to over 5000 climate articles, to bolster support of his religion, ie, AGW.
We are speaking of a person who had either blocked or banned several hundred people from wikipidea, either because they were trying to post scientific pieces that ran counter to his faith, or because they were trying to correct egregious errors he wrote into their pieces.
And you want us to listen to what he has to say, because………?
Pete says:
Perhaps a more mature comparison and analysis of his views with those of Willis would be useful … particularly to those of us who are not scientifically-inclined.
All wmconnolley did was link to a page that opens with this,
It is indeed a very fundamental question about whether the CO2 leads or lags the temperature. If there was somewhere in the ice core record where CO2 increases and temperature does not, then our understanding of the greenhouse effect must be faulty. However, so far we don’t find such a place.
Now go look at Figure 2 above and the question is answered. CO2 has increased for the last 6,000 years and temperatures have not. Ergo, their understanding of the greenhouse effect is faulty.
Its just the usual obsfurcation from warmists like wmconnolley. Post a link and rely on the fact 95% of people won’t follow it or understand it. Real Climate does this all the time.
Nick Stokes wrote:
“Their title is “Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation” Seems clear to me. And that’s what they plotted.”
That’s really what they plotted? Then why didn’t they stop plotting the graphs at 10K BP, which would be the beginning of the Holocene? Their graphs all end at <7K BP which goes beyond the last deglaciation.
Re: Pete
From the very first paragraph of the link pointed to by wmconnelly
I believe Willis’s figure 2 shows just such a place where CO2 increases without a temperature rise.
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 rise is about 10 ppm in that last period which would lead to 0.1 C of temperature increase, so it might be hard to see. The modern era was truncated off the right side of this graph, but it would currently be about 3 on that scale moving to somewhere near 10 by 2100, just to put it in perspective, so are we concerned about that little ramp of 10 ppm?
Pete says:
April 8, 2012 at 7:17 am
There have been two quite juvenile responses to wmconnelley’s link and its contents.
=============================
“Thus there is no surprise in the idea that the end of the ice age was kicked off by something other than CO2. however once it started, CO2 appears to be involved in keeping it going.”
…..yep, CO2 forced it right into another ice age
Willis is simply not showing you that the Southern Hemisphere warmed first, with the Northern Hemisphere slowly catching up over 8000 years.. This is why he says the proxy records are all over the place and shows them all together http://wattsupwiththat.files.wordpress.com/2012/04/nature_shakun_proxies_plus_co2.jpg
When you average out all the Northern Hemisphere Proxy’s and compare them to the Southern Hemisphere Proxy’s as shown in this graph http://i44.tinypic.com/34gncox.jpg you can see why some of the proxy’s have a late warming start. These proxy’s are not cherry picked, it is just the simple fact that the Hemisphere’s warmed at different times and the proxy’s show that. Here is a graph of all the proxy sites used to get a global temperature average http://i41.tinypic.com/1432dtw.jpg
If you average out all the proxy records to get a global average you can very easily see that temperatures trail CO2 http://i39.tinypic.com/f0qkcw.jpg as you can see in the graph temperatures keep on going up as CO2 levels off. This temperature/CO2 division is miniscule and is easily seen on any Holocene temperature/CO2 graph http://www.geocraft.com/WVFossils/PageMill_Images/image357_lg.gif even when compared to multiple temperature records, the Holocene is flat in line with CO2 http://ossfoundation.us/projects/environment/global-warming/myths/images/temperature-records/Holocene_Temperature_Variations_Rev.png