Plunge in CO2 put the freeze on Antarctica

Dec 01, 2011

Plunge in CO2 put the freeze on AntarcticaAtmospheric carbon dioxide levels plunged by 40% before and during the formation of the Antarctic ice sheet 34 million years ago, according to a new study. The finding helps solve a long-standing scientific puzzle and confirms the power of CO2 to dramatically alter global climate.

The study by an international team, published in the journal Science, is the first multidisciplinary research of its kind to show that CO2 was tracking at that time. It confirms that significant falls in the result in global cooling, just as rises result in global warming.

Previous studies had suggested that atmospheric CO2 over the Southern Ocean was climbing during the Eocene to Oligocene climate transition, when ice first formed over Antarctica. This presented a conundrum, suggesting the climate was warming at the same time as Antarctica was freezing.

But when the vastly different ancient Southern Ocean currents and temperatures of that period were factored in, it quickly became apparent that Antarctica's big freeze followed a fall in CO2 levels.

The paper, "The Role of Carbon Dioxide During the Onset of Antarctic Glaciation", reinforces carbon dioxide's place as a primary driver for . It was lead authored by Mark Pagani, of Yale University, and co-authored by University of NSW Climate Change Research Centre researcher Dr Willem Sijp.

"Our research recognised that the flows of deep ocean currents at the end of the Eocene were dramatically different from those of today because of the altered position and shape of continental masses," said Dr Sijp.

"Previous research relied on different temperature estimates and had also not taken these different currents into account. This led to significant upward biases in calculated CO2 which made it appear that carbon dioxide was actually increasing around the Southern Ocean as the Antarctic ice sheet formed. We can now see the reverse was true.

"We found a 40 percent CO2 decrease over a three million year period, in agreement with global cooling during that time.

"This decline was a critical condition for global cooling and the emergence of the . In short, the apparent increase of CO2 during Antarctic is refuted."

The nature of ocean currents is vital in calculating atmospheric CO2, because the estimates of atmospheric carbon dioxide are derived from measurements of molecules from algae deposited on the ocean floor at six ocean sites millions of years ago.

The fundamentally different circulation of the Southern Ocean during the directly affected the algae by changing the temperatures of these ocean currents and significantly lowering the nutrient load. This had a direct impact on the inferred CO2.

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Shootist
3 / 5 (8) Dec 01, 2011
Does this mean that an ice free Antarctica is a normal condition (I assume there are many global climate states that maintained stability for millions of years)?
that_guy
3 / 5 (6) Dec 01, 2011
This is what happened when the last intelligent species got concerned with global CO2 levels. Do we really want to freeze ourselves out of existence like them?
Vendicar_Decarian
0.5 / 5 (39) Dec 01, 2011
"Do we really want to freeze ourselves out of existence like them?" - ThatGirl

Ah, you are referring to the Atlantians. They didn't freeze, they just took their advanced technology city under water where to this day they live in splendor and luxury like the Gungans.

You might watch this doumentary.

http://www.starwa...iew.html
PPihkala
3.8 / 5 (4) Dec 01, 2011
Do we really want to freeze ourselves out of existence like them?

There is no evidence present about intelligent species present at 34 million years ago. Secondly we are not at 40% reduction situation now with CO2. The opposite is true. Currently CO2 is increasing at a rate newer seen in earths history. The change we have made with fossil fuels in last 200 years has previously taken thousands or millions of years. The slow rise was giving flora and fauna time to adjust, while now the change is too fast. Current level of CO2 should be reduced to pre-industrial levels as soon as possible. If not, we and life on earth will pay an ever increasing prize for it.
Pirouette
2.3 / 5 (4) Dec 01, 2011
That would mean travel by horse and buggy to be the optimum, since almost anything else consumes fossil fuels. . .and the house current to charge a car battery is an indirect product of coal, gas or oil. Even corn and other grains production for the purpose of making ethanol has to be harvested by fuel driven combines, tractors and other farm equipment. Bicycles, anyone?
StarGazer2011
1.6 / 5 (7) Dec 01, 2011
The Holocene Optimum 6000 years ago was 2-3 degrees warmer than now, perhaps we should be aiming for that.
StarGazer2011
1 / 5 (4) Dec 02, 2011
Did a quick read of various articles related to 'alkenone CO2 method' used in this paper.
The method measures C12/C13 ratios in fossilised plankton,ratios which are related to the amount of disolved CO2 in the WATER at the time of the planktons death.
Now, we all know warmer water 'acidifies' i.e disolves more CO2 in it, so how can you separate the falling Co2 in the water from falling temperature? How do we know CO2 wasnt precipitating from the water as it cooled towards freezing, rather than CO2 in the atmosphere dropping?
Dr Pagani may have an answer, but what is the evidence that the dropping of the C12 ratio before the ice formed wasnt caused by the water cooling towards freezing over time (it must have started cooling some time before becomming ice) and thus being able to dissolve less CO2? Pity the paper is behind a pay wall, would love to know.
As far as I can tell the alkenone method is a proxy for disolved CO2 in water, but doesnt say anything about CO2 in atmosphere.
StarGazer2011
1 / 5 (3) Dec 02, 2011
ok i totally stuffed that up by confusing proposed oceanic acidification via increased partial pressure of CO2 with that implying CO2 was less soluble at low temperatures. Solubility increases with temperature for gases. So lowering temperatures should increase CO2 all other things being equal. oops.
Vendicar_Decarian
0.2 / 5 (36) Dec 02, 2011
"ok i totally stuffed that up..." - StarGazer

Hmmmm... Who am I to trust?

Expert scientists who spend their lives developing an area of expertise and prove that expertise through peer review publication? Or.....

Know nothing nobodies who spend 30 seconds working it out for themselves and get it wrong?

If you are a student, then ask questions but otherwise keep your ignorant mouth shut.

If you are a Denialist then just keep your ignorant mouth shut.

Either way your conduct fails.

Vendicar_Decarian
0.3 / 5 (38) Dec 02, 2011
"That would mean travel by horse and buggy to be the optimum, since almost anything else consumes fossil fuels" - Spirochete

Live sustainably or die.

Nature doesn't care about your preferences, and neither do the rest of us.

reformed_optimist
3 / 5 (4) Dec 02, 2011
Vendicar

Hmmmm... Who am I to trust?

Expert scientists who spend their lives developing an area of expertise and prove that expertise through peer review publication? Or.....

Know nothing nobodies who spend 30 seconds working it out for themselves and get it wrong?

If you are a student, then ask questions but otherwise keep your ignorant mouth shut.

If you are a Denialist then just keep your ignorant mouth shut.

Either way your conduct fails.



Firstly - it appears that a number of the "climate experts" that comprise the IPCC are not actually experts in the fields that they are contributing to.

Secondly - it is a characteristic of proponents of global warming that they try to suppress dissenting viewpoints (just as you are doing). This is not an academically sound practice as it stifles constructive debate and discussion.

What gives you the right to tell anyone to "keep their ignorant mouth shut"?

yoatmon
3 / 5 (4) Dec 02, 2011
@ reformed_optimist:
During the middle ages "homo sapiens" did not observe even the most elementary hygenic measures. It is known today that the result of this behaviour resulted in the "black death" which reached its peak 1348 - 1350.

We don't crap on the front of our doorstep or the adjacent gutter anymore as our ancestors in Europe did. What we are doing now will effect not only ourselves but the whole of creation. I can understand that some individuals get to be haltless when spurred from the ignorance and stupidity of others, knowing quite well what the result of such behaviour worldwide will lead to in a relative short time span.

Sometimes I wish I could be just as ignorant and stupid as the majority of "homo sapiens" so that I could enjoy the same ease of mind when heading straight forward into disaster.
rubberman
not rated yet Dec 02, 2011
@ reformed_optimist:
During the middle ages "homo sapiens" did not observe even the most elementary hygenic measures. It is known today that the result of this behaviour resulted in the "black death" which reached its peak 1348 - 1350.

Ironically, and I'm sure it's just a coincidence, that this occurred during the MWP when the temperatures in the northern hemisphere rose suddenly and dramatically, providing an environment for disease to flourish amidst a population unprepared to deal with it....no correlation to present day with our current stock anti-biotics becoming less adept at dealing with the bugs they used to be able to handle. (see physorg article under medicine and health on antibiotic research...or lack thereof, and why).
Nanobanano
1 / 5 (1) Dec 02, 2011
"That would mean travel by horse and buggy to be the optimum, since almost anything else consumes fossil fuels" - Spirochete

Live sustainably or die.

Nature doesn't care about your preferences, and neither do the rest of us.



Actually, that probably would not be sustainable, seeing as how having that many horses would pretty much double, if not triple the amount of grazing areas we would need for animals, and of course horses breathe and fart too, just like cattle, so they make CO2 and methane.

Not to mention it would take several decades, if not centuries, to breed enough horses to increase their populations to relevant levels for even one person per household to be able to ride a horse to work. Currently, there's probably only one horse for every hundred or several hundred people in the world.

Grazing area and feed for the horses is not practical, even if most people left cities and went back to rural living...which of course would destroy even more forests..
Nanobanano
1 / 5 (1) Dec 02, 2011
Yeah, i calculate it would take an absolute minimum of 40 years to get the Horse population up to 1 Horse per 4 people even under the most idealistic of breeding circumstances.

But you'll need at least 1 acre of grazing land per horse (or at least one acre of land "somewhere" to grow the food, even if the horse is in a stall and not grazing.)

Then all your work places and stores need stalls, ties, and corals(sp?) like in a damn western movie so you can keep your horse safe while you're at work or shopping, etc.

But yeah, it takes time, food, and pollution to make more of anything, including horses.

You'll have to cut down most of the existing forests on the planet to make room for grazing lands or otherwise additional feed crops for horses.

One horse per 4 people on Earth means you'd need 2.5 million square miles of ADDITIONAL grazing land, which is about 58 times the area of the State of Louisiana.

Any other bright ideas?
Nanobanano
1 / 5 (2) Dec 02, 2011
Almost nobody in the western world has the skills to live off the land without coal and gasoline powered engines and electricity, so if wind, solar, nuclear, and hydro can't take up the slack, it's probably back to the dark ages and vassal states ruled at the edge of a sword...
Benni
1 / 5 (2) Dec 02, 2011
Vendicar

Hmmmm... Who am I to trust?

Expert scientists who spend their lives developing an area of expertise and prove that expertise through peer review publication? Or.....

Know nothing nobodies who spend 30 seconds working it out for themselves and get it wrong?

If you are a student, then ask questions but otherwise keep your ignorant mouth shut.

If you are a Denialist then just keep your ignorant mouth shut.

Either way your conduct fails.



What gives you the right to tell anyone to "keep their ignorant mouth shut"?


@reformed optimist: The best way to respond to boorish commentary, such as VD, is simply read over it just as soon as you recognize it for what it is. He doesn't understand that Democracy was born in the minds of men because they had "questions". It's his opinion only certain people should be allowed to ask questions, that's his opinion, fortunately we live in a Democracy & the rest of us can whether VD likes it or not.
Osiris1
2.3 / 5 (3) Dec 03, 2011
If Antarctica were ice free, think of the extra forest land and farm land. That would be taken up by population growth. Steven Hawking said we will need a new home ever so often. He is right.
NotParker
1 / 5 (2) Dec 03, 2011
Return Antarctica to its natural state!

Warm the planet. Melt the unnatural ice cap.

WHATTYA WANT. NO MORE ICE!

WHEN DYA WANT IT? NOW!!
Vendicar_Decarian
0.2 / 5 (36) Dec 04, 2011
"If Antarctica were ice free, think of the extra forest land and farm land. That would be taken up by population growth" - Osirus

If Antarctica were ice free it would remain an barren wasteland as all of the soil on the continent's interior has been scraped off of the continent by the action of Glaciers.

Vendicar_Decarian
0.2 / 5 (36) Dec 04, 2011
"What gives you the right to tell anyone to "keep their ignorant mouth shut"?" - Reformed Optimist

Are you telling me to keep my mouth shut Tard Boy?
Nanobanano
1 / 5 (1) Dec 04, 2011
If Antarctica were ice free, think of the extra forest land and farm land. That would be taken up by population growth. Steven Hawking said we will need a new home ever so often. He is right.


If the antarctic were ice free the earth would have no means of temeprature regulation except astronomical winter and night time.

The heat of fusion of water is one of the strongest buffers to extreme temperature change, in this case extreme temperature rise.

If antarctica was ice free (Let's just assume in summer only, and at least any time soon and by any means other than continental drift over eons,) then the average albedo will be changed by about 5 to 10 points, and the average temperature of the planet would probably be tens of degrees CELSIUS hotter, and most life forms would be extinct.

By the time you melt Greenland and maybe 10% of antarctica, the air temperature and climate will become a serious threat to human existance.
NotParker
1.8 / 5 (4) Dec 04, 2011
Antarctica was completely ice free 40 million years ago and ice didn't start forming until Australia broke off.

It wasn't until about 15 million years ago that the ice cap was relatively complete.

Of course CO2 was much higher.
Vendicar_Decarian
0.2 / 5 (36) Dec 05, 2011
"The Holocene Optimum 6000 years ago was 2-3 degrees warmer than now" - StarTard

It was? You should write a scientific paper on your discovery.

Meanwhile, back here in reality land...

In terms of the global average, temperatures were probably colder than present day (depending on estimates of latitude dependence and seasonality in response patterns). While temperatures in the Northern Hemisphere were warmer than average during the summers, the tropics and areas of the Southern Hemisphere were colder than average which comprised an average global temperature still overall lower than present day temperatures. - Link below

http://www.agu.or...24.shtml

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