From Purdue University , another “just in time for Durban” press release. When you see phrases like “the mother of all tipping points” and you know this is overhyped control knob science.
Drop in carbon dioxide levels led to polar ice sheet, study finds
WEST LAFAYETTE, Ind. – A drop in carbon dioxide appears to be the driving force that led to the Antarctic ice sheet’s formation, according to a recent study led by scientists at Yale and Purdue universities of molecules from ancient algae found in deep-sea core samples.
The key role of the greenhouse gas in one of the biggest climate events in Earth’s history supports carbon dioxide’s importance in past climate change and implicates it as a significant force in present and future climate.
The team pinpointed a threshold for low levels of carbon dioxide below which an ice sheet forms in the South Pole, but how much the greenhouse gas must increase before the ice sheet melts – which is the relevant question for the future – remains a mystery.
Matthew Huber, a professor of earth and atmospheric sciences at Purdue, said roughly a 40 percent decrease in carbon dioxide occurred prior to and during the rapid formation of a mile-thick ice sheet over the Antarctic approximately 34 million years ago.
A paper detailing the results was published Thursday (Dec. 1) in the journal Science.
“The evidence falls in line with what we would expect if carbon dioxide is the main dial that governs global climate; if we crank it up or down there are dramatic changes,” Huber said. “We went from a warm world without ice to a cooler world with an ice sheet overnight, in geologic terms, because of fluctuations in carbon dioxide levels.”
For 100 million years prior to the cooling, which occurred at the end of the Eocene epoch, Earth was warm and wet. Mammals and even reptiles and amphibians inhabited the North and South poles, which then had subtropical climates. Then, over a span of about 100,000 years, temperatures fell dramatically, many species of animals became extinct, ice covered Antarctica and sea levels fell as the Oligocene epoch began.
Mark Pagani, the Yale geochemist who led the study, said polar ice sheets and sea ice exert a strong control on modern climate, influencing the global circulation of warm and cold air masses, precipitation patterns and wind strengths, and regulating global and regional temperature variability.
“The onset of Antarctic ice is the mother of all climate ‘tipping points,'” he said. “Recognizing the primary role carbon dioxide change played in altering global climate is a fundamentally important observation.”
There has been much scientific discussion about this sudden cooling, but until now there has not been much evidence and solid data to tell what happened, Huber said.
The team found the tipping point in atmospheric carbon dioxide levels for cooling that initiates ice sheet formation is about 600 parts per million. Prior to the levels dropping this low, it was too warm for the ice sheet to form. At the Earth’s current level of around 390 parts per million, the environment is such that an ice sheet remains, but carbon dioxide levels and temperatures are increasing. The world will likely reach levels between 550 and 1,000 parts per million by 2100. Melting an ice sheet is a different process than its initiation, and it is not known what level would cause the ice sheet to melt away completely, Huber said.
“The system is not linear and there may be a different threshold for melting the ice sheet, but if we continue on our current path of warming we will eventually reach that tipping point,” he said. “Of course after we cross that threshold it will still take many thousands of years to melt an ice sheet.”
What drove the rise and fall in carbon dioxide levels during the Eocene and Oligocene is not known.
The team studied geochemical remnants of ancient algae from seabed cores collected by drilling in deep-ocean sediments and crusts as part of the National Science Foundation’s Integrated Ocean Drilling program. The biochemical molecules present in algae vary depending on the temperature, nutrients and amount of dissolved carbon dioxide present in the ocean water. These molecules are well preserved even after many millions of years and can be used to reconstruct the key environmental variables at the time, including carbon dioxide levels in the atmosphere, Pagani said.
Samples from two sites in the tropical Atlantic Ocean were the main focus of this study because this area was stable at that point in Earth’s history and had little upwelling, which brings carbon dioxide from the ocean floor to the surface and could skew measurements of atmospheric carbon dioxide, Huber said.
In re-evaluating previous estimates of atmospheric carbon dioxide levels using deep-sea core samples, the team found that continuous data from a stable area of the ocean is necessary for accurate results. Data generated from a mix of sites throughout the world’s oceans caused inaccuracies due to variations in the nutrients present in different locations. This explained conflicting results from earlier papers based on the deep-sea samples that suggested carbon dioxide increased during the formation of the ice sheet, he said.
Constraints on temperature and nutrient concentrations were achieved through modeling of past circulation, temperature and nutrient distributions performed by Huber and Willem Sijp at the University of New South Wales in Australia. The collaboration built on Huber’s previous work using the National Center for Atmospheric Research Community Climate System Model 3, one of the same models used to predict future climates, and used the UVic Earth System Climate Model developed at the University of Victoria, British Columbia.
“The models got it just about right and provided results that matched the information obtained from the core samples,” he said. “This was an important validation of the models. If they are able to produce results that match the past, then we can have more confidence in their ability to predict future scenarios.”
In addition to Huber, Pagani and Sijp, paper co-authors include Zhonghui Liu of the University of Hong Kong, Steven Bohaty of the University of Southampton in England, Jorijntje Henderiks of Uppsala University in Sweden, Srinath Krishnan of Yale, and Robert DeConto of the University of Massachusetts-Amherst.
The National Science Foundation, Natural Environment Research Council, Royal Swedish Academy and Yale Department of Geology funded this work.
In 2004 the team used evidence from deep-sea core samples to challenge the longstanding theory that the ice sheet developed because of a shift from warm to cool ocean currents millions of years ago. The team found that a cold current, not the warm one that had been theorized, was flowing past the Antarctic coast for millions of years before the ice sheet developed.
Huber next plans to investigate the impact of an ice sheet on climate.
“It seems that the polar ice sheet shaped our modern climate, but we don’t have much hard data on the specifics of how,” he said. “It is important to know by how much it cools the planet and how much warmer the planet would get without an ice sheet.”
Writer: Elizabeth K. Gardner, 765-494-2081, ekgardner@purdue.edu
Sources: Matthew Huber, 765-494-9531, huberm@purdue.edu
Mark Pagani, 203-432-6275, mark.pagani@yale.edu
Related website:
Matthew Huber Climate Dynamics Prediction Laboratory: http://web.ics.purdue.edu/~huberm/Matthew_Hubers_Climate_Dynamics_Prediction_Laboratory/CDPL.html
Related news releases:
Antarctic iced over when greenhouse gases – not ocean currents – shifted, study suggests: http://www.purdue.edu/uns/html4ever/2004/041227.Huber.Antarctica.html
Prehistoric global cooling caused by CO2, research finds: http://www.purdue.edu/uns/x/2009a/090226HuberPete.html
Abstract on the research in this release is available at: http://www.purdue.edu/newsroom/research/2011/111201HuberGlaciation.html
As an aside, I was watching a tv doc – Nat Geo possibly – about the snowball Earth episode. Much to my amusement, it wasn’t long into the program when the CO2-causes-snowball-earth-then-releases-it theory of climate was presented.
The deficiencies in the theory were everywhere. I wanted them to explain what levels of CO2 the atmosphere had fallen from and to, in order to precipitate this catastrophe. No figures were ever mentioned. Next, they were forced to explain how CO2 manages to end the icy grip of snowball Earth. Their explanation for how this occured was that eventually, volcanic activity released sufficient CO2 into the atmosphere to raise it to hot house levels.
I say the volcanoes “eventually” did this, because, remember, the snowball earth episode lasted for more than 20 million years by their own admission. According to the “chilling stars” book, it was a period lasting nearer 100 million years which saw ice expanding and retreating. So why am I unconvinced by the volcano theory? Simply because of the time involved. Volcanic activity was pretty intense 600 million years ago, so why did it take at least 20 million years for volcanoes to release sufficient CO2 to warm the planet? Remember that during snowball earth, there was little plant life to take it up. so any C02 released would just have accumulated. Did volcanic activity go on hold for 20 million years?
None of these explanations make any sense. None of them stand up to scrutiny. Any scientist worthy of the name would have put aside such childish musings. Yet such times do we live, that CO2 is trotted out as the answer for every change in climate, whether up or down or occurring over decades or millions of years, regardless of the flaws in reasoning. With the onset of Durban, we can only expect an avalanche of this nonsense.
Someone please explain to me why there doesn’t seem to be a problem inherent in the fact that we are currently at CO2 levels hovering around 400 ppm, yet the ice sheets are melting” If CO2 drives temperature, CO2 around 1000 ppm would supposedly melt the ice sheets and CO2 at 600 ppm creates ice sheets, why aren’t the ice sheets getting thicker. Is this a dumb question?
G. Karst says:
December 2, 2011 at 8:20 am
If lack of CO2 caused the ice ages, would someone explain why we are doing, our best, to lower it’s atmospheric concentration. Does anyone really believe that increased glaciation is good? Besides how can we have increasing CO2 concentrations while temperatures have been flat for half a climatic period? Is logic dead? GK
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So according to “Scientists” more CO2 causes a DECREASE in glaciation and an INCREASE in plant growth (crops) not to mention an increase in biodiversity.
I want MORE CO2 not less, bring on the Eocene!
These people need to be reminded that Australia used to be joined to Antartica and at that time the ocean currents were forced north round Australia into the tropics.Antartica was much warmer and indeed small dinosaurs lived there. Australia has since broken away and is heading for India,you can’t waterski behind it but thats where it’s going. Consequently the climate on Antartica has changed dramatically. Co2 is nonsense.
If the question is which drops first, temperature or CO2, maybe a play on an age old question could be used by alarmists to make the proof – which drops first, a chicken (temperature) or an egg (CO2)?
I can visualize Bill Nye, on Gore’s next 24 Hours of Reality, holding a chicken by the neck in one hand, and an free range organic egg in the other. “Yes kids, this is an easy, do-it-yourself-at-home science experiment which conclusively proves, when released at the same time, CO2 drops before, and faster than, temperature. Hold the chicken and egg above a hot frying pan, let ’em go, and graphically see for yourself – (a) which drops fastest, (b) the dire consequences of the fall and (c) what will happen to the planet if we don’t reduce CO2 emissions….Next year, I’ll show you how you can tie carrots to skeptics’ noses and prove they weigh less than ducks, and should therefore be burned at the stake as witches. Isn’t science wonderful?”
….oh the humanity of it all….
Somebody’s got to say it.
Purdue, they do chicken, right?
Earth was warm and wet. Mammals and even reptiles and amphibians inhabited the North and South poles, which then had subtropical climates. Then, over a span of about 100,000 years, temperatures fell dramatically, many species of animals became extinct, ice covered Antarctica and sea levels fell as the Oligocene epoch began.
And this cold world is where they want to take us back to?
Billy Liar says:
December 2, 2011 at 9:07 am
Somebody’s got to say it.
Purdue, they do chicken, right?
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Yes, as a matter of fact they do!
…Purdue University animal sciences professor Bill Muir was part of an international research team that analyzed the genetic lines of commercial chickens used to produce meat and eggs around the world. Researchers found that commercial birds are missing more than half of the genetic diversity native to the species, possibly leaving them vulnerable to new diseases and raising questions about their long-term sustainability…..
He said it’s also important to preserve non-commercial breeds and wild birds for the purpose of safeguarding genetic diversity and that interbreeding additional species with commercial lines might help protect the industry…..
http://www.purdue.edu/uns/x/2008b/081103MuirDiversity.html
Purdue used to be a darn fine agricultural school. Most of the dorm food was from their farms and quite tasty.
Kelvin Vaughan says:
December 2, 2011 at 10:17 am
Earth was warm and wet. Mammals and even reptiles and amphibians inhabited the North and South poles, which then had subtropical climates. Then, over a span of about 100,000 years, temperatures fell dramatically, many species of animals became extinct, ice covered Antarctica and sea levels fell as the Oligocene epoch began.
And this cold world is where they want to take us back to?
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Yeah, That is my reaction too.
Warm, wet and teeming with life and these idiots want to kill all possibility of that. Go Figure.
Even if CO2 has nothing to do with the climate, it has a LOT to do with “teeming with life .” How anyone can vilify a natural plant fertilizer is beyond me but then the People’s Republic of Taxachusetts outlawed my giving manure to my neighbors for their gardens…
saltspringson says:
December 2, 2011 at 9:00 am
If the question is which drops first, temperature or CO2, maybe a play on an age old question could be used by alarmists to make the proof – which drops first, a chicken (temperature) or an egg (CO2)?
I can visualize Bill Nye, on Gore’s next 24 Hours of Reality, holding a chicken by the neck in one hand, and an free range organic egg in the other……
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And I can visualize PETA hauling Bill Nye and Al Gore off to court for abusing the chicken and the egg. (snicker)
Enough of this bull! Cold kills, full stop.
This clearly refutes the idea that current co2 levels are”unprecedented”
Gail Combs says:
December 2, 2011 at 8:02 am
Grasses are C4 and are a response to a much lower atmospheric CO2 level BTW so the lowering of CO2 happened before the Ice Ages.
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Gail, the other obvious one was the carboniferous…..and how it was named……..”coal”
The shallow warm seas gave us limestone then too…………
Both show up as a rapid decline in CO2 levels.
Everyone knows that CO2 effects life……but have a hard time with life effecting CO2
As CO2 only accounts for 3–5% of the light-heat conversion gases (greenhouse gases do not exist), a decrease in the CO2 or a loss of 1-2% would NOT trigger a cold period. These idiots vastly over-estimate the ability of a trace gas to affect climate. When a trace gas, which already has a limited effect and is already at about 90% of its Beer’s Law limit, decreases, it is not proportionate in effect. A one-third decrease would only cause maybe a 1/6th-1/8th decrease in effect—not enough to cause a huge climate shift. OUr recent CO2 increase is the same as the decrease that they suggest and nothing happened, yep nothing.
As long as they are willing to use the fabricated thermodynamic constant the IPCC created for CO2, assume water vapor to driven by CO2 as a positive feedback factor, and ignore the water cycle and water vapor’s role in the convectional transfer of heat to altitude, they will continue to fail to reach sensible conclusions.
AND do not forget that the policies being pushed to “fight” global warming have nothing to do with science or climate. It is all about wealth redistribution, power, money, crippling the Western economies, stunting third world development, and establishing a totalitarian and socialist one-world government based on environment and climate.
It is a political agenda which does not have the good of the people, the ecology, or the planet in mind. This is a world-level attack of communism, socialism run by a gang. Being based on climate and environmentalism, the ruling class would impose anything they please, always claiming the good of the natural world at the expense and suffering of the evil humans.
higley7 says:
December 2, 2011 at 1:44 pm
…It’s a political agenda….
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Very much so.
How supposedly intelligent people connected with universities and the new media can go along with a scam designed to return the world to poverty, serfdom and a new type of “feudalism” simply floors me. I guess they hope is to be one of the masters and not one of the serfs.
There never was a Snowball Earth or a hyper CO2 episode.
THere is a much better theory, due to GE Williams,
Earth Science Reviews v 34 #1, March 1993 (108 G Scholar citatations)
http://www.sciencedirect.com/science/article/pii/001282529390004Q
updated again at v 87 #3-4, March 2008, pp 61-93, abstract at
http://www.sciencedirect.com/science/article/pii/S0012825207001808
This rad idea is discussed in a paper here
http://www.dgf.uchile.cl/~ronda/GF3004/jen00.pdf
and another here
http://www3.geosc.psu.edu/~jfk4/PersonalPage/Pdf/Nature_98.pdf
Lots more on Google scholar
High obliquity of the Earth’s axis, about 70 degrees (!) explains
both the low-latitude glaciation and the Faint Young Sun Paradox,
along with the high-temperature bottleneck of life’s origin.
At 70 axial tilt, the poles get more sunlight than the equator,
so much more solar heat than water temps go to 60C every summer,
hence the requirement for early life to withstand hot water
in spite of the sun being only 70% as luminous as it is today.
Snowball Earth need only be invoked assuming low Proterozoic obliquity,
so no CO2 rescue need be hypothesized.
Low obliquity can’t explain the extreme seasonality of Proterozoic sediments.
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I think you guys have it exactly right.
I’d be willing to bet that this “study” was not peer reviewed by any competent geologists.
Regarding Snowball Earth, what do you think would happen if Antarctica were 10 times bigger;
… let’s say, a circular continent covering the South Pole all the way to southern Africa and southern Brazil. Or lets say, continental drift had piled up most of the continents together over the South Pole.
Where would the glaciers stop?
I don’t think they would. The centre of the continent would build up glaciers 5 kms high, and they would push out by gravity and local albedo effect all the way to the continental shelves at 35S.
Sea level would fall 250 metres, the Albedo impact of all that white glacier would reflect enough sunlight to cool the Earth by 15C to 25C. The North Pole would freeze up. Any other landmasses would develop glaciers. Only the tropics would be ice-free but they would be 10C cooler than today.
This is exactly the conditions and the continental configurations of the last two Snowballs.
No CO2 needs to be involved in this explanation at all. In fact, it would take CO2 levels of about 200,000 ppm to break up such a Snowball scenario. The only estimates of CO2 in the last two Snowballs is 12,000 ppm and 8,000 ppm, far too low to have any impact on a Snowball at all.
That is the real factual explanation based on the geologic and proxy evidence available. Snowballs break-up when continental drift eventually moves all of these continents off the South Pole.
In one of the emails, a postgraduate student tells Briffa about a conversation he had with Tim Lenton about ‘tipping points’:
http://www.ecowho.com/foia.php?file=1126.txt&search=Dissertation+thoughts+and+PhD+application
If that is what you are looking for, that is what you will find.
“Data generated from a mix of sites throughout the world’s oceans caused inaccuracies due to variations in the nutrients present in different locations. This explained conflicting results from earlier papers…”
So simple. Sites with data that agrees with theory are “good”. Sites with data that disagree with theory are “bad”. Get rid of the bad data, and voila, theory upheld.
More importantly however, if Antarctica was once a lush tropical paradise teaming with life, there ought to be a sh*tload of coal, oil, natural gas…
Dear David, There are some fine thick coal seams exposed in the cliff faces of Antarctica along with a fine fossil assemblage of glossopteris and gangamopteris leaves. So far the international agreement has been to keep Antarctica a mining free zone, The probable rise of shale gas usage will help to leave Antarctica unmolested, Geoff Broadbent
Another correlational study using computer models. Yawn!
davidmhoffer says:
December 3, 2011 at 7:44 pm
… if Antarctica was once a lush tropical paradise teaming with life, there ought to be a sh*tload of coal, oil, natural gas…
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Antarctica is the unlucky continent in that continental drift has left it near the South Pole or connected to other land over the South Pole for most of the last 750 million years. It has been glaciated over in about 5 different epochs.
It probably has very little coal, oil and gas given this issue.
Between 250 Mya and 50 Mya, there was little glaciation but the continent would have been very cold in the winter. There are dinosaur, marsupial, marine and tree fossils from the period but there was probably snow on the ground for several months in the winter. There could be some coal, oil and gas reserves from this period but probably not much.
To me the most interesting thing about this study is the finding of synchronicity of ice cover at the two poles. If the a hallmark of CO2 heating is melting and growing simultaneously at both poles than we don’t have it.
As to CO2 and temperature, it is perhaps instructive to view it in the last 50 years where we have better data and good measures of CO2. http://www.woodfortrees.org/plot/esrl-co2/isolate:60/mean:12/scale:0.2/plot/hadcrut3vgl/isolate:60/mean:12/from:1958
RE: Main Article
“The evidence falls in line with what we would expect if carbon dioxide is the main dial that governs global climate; if we crank it up or down there are dramatic changes,” Huber said. “We went from a warm world without ice to a cooler world with an ice sheet overnight, in geologic terms, because of fluctuations in carbon dioxide levels.”
Yes, this sounds like research intended to prove the carbon-dioxide dial hypothesis. I would hope no public funds were spent on this study which may have been conducted only to support the activist belief that a plausible emergency exists, which demands that we all quit using ‘Carbon Power’ as soon as possible.
If this is a balanced study, it will include a summary of alternative interpretations of the same data other than the carbon-dioxide dial hypothesis.
This plot of calculated radiative-forcing of CO2 (sometimes mistakenly called radioactive-forcing) would seem to contradict that hypothesis, as CO2 is seen only to have a limited effect on a narrow central zone of outgoing thermal radiation from the earth at 20 km up:
File:ModtranRadiativeForcingDoubleCO2.png
“From Wikipedia, the free encyclopedia”
http://en.wikipedia.org/wiki/File:ModtranRadiativeForcingDoubleCO2.png