Meanwhile today while CO2 is increasing, the Antarctic ice cap is also increasing.
Bill Illis writes about it:
Ice sheets formed in Antarctica about 35 million years ago when CO2 was about 1,200 ppm. Ice sheets also formed in Antarctica about 350 to 290 million years ago when CO2 was about 350 ppm. Ice sheets also formed in Antarctica about 450 to 430 million years ago when CO2 was about 4,500 ppm. The more common denominator is when continental drift places Antarctica at the south pole.
Below, Antarctica today.
New data illuminates Antarctic ice cap formation
From a Bristol University Press release issued 13 September 2009
A paper published in Nature
New carbon dioxide data confirm that formation of the Antarctic ice-cap some 33.5 million years ago was due to declining carbon dioxide in the atmosphere.
A team of scientists from Bristol, Cardiff and Texas A&M universities braved the lions and hyenas of a small East African village to extract microfossils from rocks which have revealed the level of CO2 in the Earth’s atmosphere at the time of the formation of the ice-cap.
Geologists have long speculated that the formation of the Antarctic ice-cap was caused by a gradually diminishing natural greenhouse effect. The study’s findings, published in Nature online, confirm that atmospheric CO2 started to decline about 34 million years ago, during the period known to geologists as the Eocene – Oligocene climate transition, and that the ice sheet began to form about 33.5 million years ago when CO2 in the atmosphere reached a tipping point of around 760 parts per million (by volume).
The new findings will add to the debate around rising CO2 levels in the Earth’s atmosphere as the world’s attention turns to the UN Climate Conference in Copenhagen which opens later this year.
Dr Gavin Foster from the University of Bristol and a co-author on the paper said: “By using a rather unique set of samples from Tanzania and a new analytical technique that I developed, we have, for the first time, been able to reconstruct the concentration of CO2 across the Eocene-Oligocene boundary – the time period about 33.5 million years ago when ice sheets first started to grow on Eastern Antarctica. “
Professor Paul Pearson from Cardiff University’s School of Earth and Ocean Sciences, who led the mission to the remote East Africa village of Stakishari said: “About 34 million years ago the Earth experienced a mysterious cooling trend. Glaciers and small ice sheets developed in Antarctica, sea levels fell and temperate forests began to displace tropical-type vegetation in many areas.
“The period culminated in the rapid development of a continental-scale ice sheet on Antarctica, which has been there ever since. We therefore set out to establish whether there was a substantial decline in atmospheric carbon dioxide levels as the Antarctic ice sheet began to grow.”
Co-author Dr Bridget Wade from Texas A&M University Department of Geology and Geophysics added: “This was the biggest climate switch since the extinction of the dinosaurs 65 million years ago.
“Our study is the first to provide a direct link between the establishment of an ice sheet on Antarctica and atmospheric carbon dioxide levels and therefore confirms the relationship between carbon dioxide levels in the atmosphere and global climate.”
The team mapped large expanses of bush and wilderness and pieced together the underlying local rock formations using occasional outcrops of rocks and stream beds. Eventually they discovered sediments of the right age near a traditional African village called Stakishari. By assembling a drilling rig and extracting hundreds of meters of samples from under the ground they were able to obtain exactly the piece of Earth’s history they had been searching for.
Further information:
The paper:Atmospheric carbon dioxide through the Eocene–Oligocene climate transition. Paul N. Pearson, Gavin L. Foster & Bridget S. Wade. Nature online, Sunday 13th September.
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Smokey (15:44:54) : “. . . to the major atmospheric component O2.”
I got a bit lost on the exchange between you and Det, so just to keep the facts straight for the current atmosphere:
Dry air contains roughly (by volume) 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.038% carbon dioxide, and trace amounts of other gases.
http://en.wikipedia.org/wiki/Earth's_atmosphere
Why did they make their research in Africa, they should have gone to antarctica!
Next time send them to the geographical south pole to dig for fossiles!
Another weird scientist, this time from the IPCC:
http://network.nationalpost.com/np/blogs/fullcomment/archive/2009/09/11/lorne-gunter-global-warming-takes-a-break.aspx
I am intrigued as to what is so special about the microfaunal samples across the Eoc-Oligo boundary in this particular well compared to those recovered from the many thousands of microfaunally sampled wells worldwide penetrating the same, let alone outcrop exposures. .
“Dr Gavin Foster from the University of Bristol and a co-author on the paper said: “By using a rather unique set of samples from Tanzania and a new analytical technique that I developed, we have, for the first time, been able to reconstruct the concentration of CO2 across the Eocene-Oligocene boundary – the time period about 33.5 million years ago when ice sheets first started to grow on Eastern Antarctica. “”
Before they make any claims they should verify the results by sampling rocks from the same time period from other places in the world. To be certain that this was not a “one off” occurance they (and others) need to sample and obtain similar results from similar rocks from other periods of icecap formation and to determine that the answer is “not in the method” they need to prove that similar rocks from non icecap forming times do not give similar results.
As an exploration geologist I’ve run across too many cases where instrumental analysis returned positive and repeatable values (for gold.) Unfortunately reliable assay techniques (fire assay techniques that have been perfected over 3000 years) failed to verify the presence of the reported amount of gold. Unfortunately the promoters were often convinced there was actually gold in the rocks that didn’t report to a fire assay and subsequently raised millions from unsophisticated investors.
Most saw the light when I advised that one gets paid for their gold only on the basis of a fire assay.
Dr Fosters “unique set of samples” and “new analytical technique” raise too many red flags. While he may be convinced he needs to have others verify his results on similar but not “unique” samples from elsewhere in the world.
IIRC, Antarctic ice cores already document a correlation (with time lag) between temperature proxies and carbon dioxide. This work apparently extends the correlation to a time with no antarctic ice cap. So this would seem to be more of an expansion of current knowledge than a breakthrough.
It is obvious from the data that modern CO2 is much more robust than CO2 was at two times in the past. The quantity of the CO2 is much less important than its robustness.
The new findings will add to the debate around rising CO2 levels in the Earth’s atmosphere as the world’s attention turns to the UN Climate Conference in Copenhagen which opens later this year.
[1] The “debate” referred too, is only over how much CO2 emissions needs to be cut back…
[2] The primary reason for the paper is explicitly described above – the UN Climate Conference in Copenhagen.
As Bill points out earlier – CO2 is all over the place while Antartica has ice.
However, whenever Antartica is over the south pole (by itself) it’s ice bound.
Smokey,
“CO2 is about 387 parts per million…” and was about 280 ppm 150 years ago. As with so many things, the issue is about the variation, not the absolute number.
Glad to see you back. You owe me a response my take up of the wager you proposed on “Forecasting the Earth’s-temperature” September 12 at 01:58:31.
How about it?
Someone once told me, that Occam’s razor was very good for these kinds of circumstances. I take continental drift for 1000.
Peter Plail (14:08:41) :
“Can any geologists out there confirm that “geologists have long speculated that the formation of the Antarctic ice-cap was caused by a gradually diminishing natural greenhouse effect”.”
Well, it’s the first time that this geologist has heard of this.
I did a very simpleminded calculation some months ago. Just from the thickness of the ice, area of the continents, and area of ocean, one gets 70 metres if I didn’t make a slip-up. It is safe to say that is an absoloute upper limit. I didn’t take into account the extra water needed to flood the land areas inundated (which would be significant and not available for sea level rise), nor more difficult effects like land area rebound or sinking of ocean floor etc. But it gives an ‘outer envelope’ estimate of the worst that could possibly happen. And of course, you get a continent and a huge island in return.
William, let’s ignore for the moment the unlikely outcome of the “global melt”. If the ice shields of Greenland and Antarctica melt, what will be exposed is not usable land, but the base rock scoured clean. It will take tens of thousands of years for that rock to become fertile soil. The facetious argument about all that extra land compensating for the loss of the current sea-level landmass is amusing. But it doesn’t offer a practical equivalency of what is gained against what is lost.
RickA (14:03:15) :
Go look at Mars polar caps.
It is there that you will find the answer.
Under the C02 snow of Mars Northern Polar Cap is predominately water ice (H20).
When Earth gets cold enough, we will have CO2 snow in Antarctica.
The people going to Copenhagen will never be satisifed with less than the latest gross exaggerations to prop up thier claim of saving the Planet. They have no such ambition other than to rule the world.
Some things do not change.
Bill Illis (13:55:07) :
“The more common denominator is when continental drift places Antarctica at the South Pole.”
Agreed. Indeed, we are lucky that there is no continental mass underneath the Arctic; if we did, mankind would still be barbecuing mammoth meat in caves somewhere in the frozen Sahara.
The growth of Antarctica ice is unsettling, particularly the extent of the ice shelf during the southern hemisphere winter, as it might be possible that, if the trend continues, it could create an atmospheric pressure imbalance between the northern and southern hemispheres that in turn prompts the cold arctic jet streams to glide down further south than the past norm during the northern summer, thereby causing lower temperature to dominate the crop growing season in Canada and the northern US—the world’s most productive agricultural regions. It could spell a major disaster for the world’s food supply situation in the near future if it could happen.
Let me squeeze in a little scientific method here, as gauche as that may be. Decreasing CO2 didn’t cause ice caps to form. It is a coincidence. Why? Because CO2 does not drive temp. Ice caps form not because of absence of CO2. They form because of cooler temperatures. Tectonics aside, whatever caused the temps to drop, CO2 dropped afterward, as it always does. And then the caps formed, more realistically, as causality from whatever caused the Earth to cool. CO2 does not drive cooling or heating. Never has, never will. We get momentary spikes in CO2 that coincide with cooling. They’re called volcanic eruptions. One decent blow-up puts as much CO2 in the air as all of man’s contribution to date. What happens? The earth cools, the “nuclear winter” effect, from aerosols in the atmosphere and CO2 is powerless to stop it. Anyone remember building volcano experiments in the 8th grade?
Between 40 million to 35 million years ago, Antarctic separated from South America (creating the Drake Passage) and separated from Australia, which allowed Antarctica to become isolated by atmospheric winds and ocean currents in an extreme polar climate.
Antarctica probably already had significant glaciers as early as 80 million years ago. The initial continental-scale glaciation of 35 million years ago (CO2 1,200 ppm) melted back starting about 27 million years ago (CO2 450 ppm) and the reglaciated about 14 million years ago (CO2 211 ppm).
http://img20.imageshack.us/img20/2464/tempvsco267m.png
There is a higher resolution animation of Antarctic continental drift here from 200 million years ago to today. (In a power point slide animation – the download might be very slow).
http://www.ig.utexas.edu/research/projects/plates/movies/akog.ppt
Here is Antarctica about 300 million years ago (CO2 350 ppm) (in the centre of the white glacier patch at the bottom).
http://upload.wikimedia.org/wikipedia/commons/0/04/LateCarboniferousGlobal.jpg
At some point during the Ordovician ice age, 440 million years ago (CO2 4,700 ppm), Gondwana (a super-continent composed of South America, Africa, India, Antarctic and Australia) made a rapid transit across the South Pole and then backed up North again during which Antarctica would have been glaciated at some point (Africa had most of the glaciers).
http://www.palaeos.com/Paleozoic/Ordovician/Maps/MidOrd.jpg
There have been good questions raised about the methodology of this paper here. Having seen many such challenges raised against papers from the pro-AGW side, I no longer take their research seriously. Its like when they say “this summer will be among the hottest on record,” “the polar bears will be extinct in 50 years,” “all the polar ice will be gone in 20 years,” I now just assume anything they say is not objective science but “fudged” in some way to support their agenda. Given their track record, it is imprudent to believe that any “science” produced by them is objective, truthful, or worth reading or spending any time thinking about.
“By assembling a drilling rig and extracting hundreds of meters of samples from under the ground [instead of from above it? bloody clever!] they were able to obtain exactly the piece of [fiction] they had been searching for.”
Peter Plail (13:55:16) : “I had to double check my calendar – no, it’s definitely not April 1st.”
Every day is April 1st with these people.
Hows does declining co2 levels recorded in a bore in Africa prove the antartic ice mass formed due to falling co2 levels?!? Did I miss something???
There is no mention here of what global temperatures were doing whatsoever and no proof of causation!
If the earth was cooling (for whatever reason), then co2 levels would also be falling, as the colder sea would absorb it from the atmosphere, and with cooling comes ice. Sounds like they are putting the cart before the horse and ignoring inconvenient little things like global temperature, millankovitch cycles, continental drift etc…
It should never have been published with the assumptions about antarctic ice, what has happened to the peer review process???? Do we no longer need to provide evidence so long as a paper mentions ice melting or claims its “worse than we thought”!
[“A team of scientists from Bristol, Cardiff and Texas A&M universities braved the lions and hyenas of a small East African village to extract microfossils from rocks which have revealed the level of CO2 in the Earth’s atmosphere at the time of the formation of the ice-cap.”]
….. So, if I rustle up a dead mouse skeleton from about 1600AD… I should be able to tell exactly what the atmospheric CO2 content was during the years that it lived?…….. How is that done exactly…. By looking at the patterns they make when you chuck ’em on the ground… Or do you put them in a rattle and shake them after smoking something strange?
So anyway, why are we measuring CO2 on Mauna Loa for? We just need dead mice…. Don’t we?
Sigh… Temperature proxies… I think we have now attained Science by proxy….. Or is that “Claytons” Science. The Science you do when you aren’t doing Science…. http://en.wikipedia.org/wiki/Claytons
(the claytons link is for non Aussies that don’t get the joke)
http://www.sciencedaily.com/releases/2009/04/090420121335.htm
1: The Earth’s orbit around the sun is not completely circular, but slightly elliptical. The orbit is ‘elastic’ and contracts and expands in a cycle of 100.000 years. And the closer we are to the Sun, the more solar radiation and the more heat we receive.
2: The Earth’s axis has a tilt in relation to the Sun and that is why we have summer and winter. But the tilt is not constant, it swings between 22 degrees and 24 degrees, and the greater the tilt, the greater the difference between summer and winter. This cycle takes 40.000 years.
3: The Earth rotates around on its axis like a top – this gives day and night. But due to the tilt of the Earth and the elliptical orbit the direction changes with a cycle of 20.000 years. This results in varation in to whether the Earth is nearest the Sun during the summer or during the winter.
Above is the understanding of climate forcings today. These forcings are some of the forcings working on the climate through millions of years.
http://global-warming.accuweather.com/2009/09/has_the_solar_minimum_countera.html
Right now its the artic that is the first serious symptom showing up. As goes the artic so goes the rest of the world to follow later for more serious symptoms.
The four drivers………
1. Volcanic aerosols- cooling influence
2. El Nino- warming influence
3. Greenhouse gases- warming influence
4. Solar cycle- variable influence.
The first 3 describe #4 above. These all apply to today and the atmosphere of the past.
Is it possible that the global temps cooled first, ice formed, and then CO2 levels dropped? I already had to learn that ice core data shows CO2 lags temperature by about 800 years. We could have a similar CO2 lag here…
Of course, it’s only coincidence that all this happened just after Antarctica separated from Australia and South America in the final stages of the breakup of Gondwana. The ice cap started forming just after Antarctica moved south of the Antarctic Circle, but it was the drop in CO2 that caused the ice.
http://en.wikipedia.org/wiki/Gondwana#Cenozoic
Looks like somebody had better clean up the Wikipedia article.
Correlation does not equal causation. The authors apparently missed beginners logic.