It seems Antarctica once had vegetation and had a lot of rain.
This artist’s rendition created from a photograph of Antarctica shows what Antarctica possibly looked like during the middle Miocene epoch, based on pollen fossil data. Image credit: NASA/JPL-Caltech/Dr. Philip Bart, LSU › Full image and caption
PASADENA, Calif. — A new university-led study with NASA participation finds ancient Antarctica was much warmer and wetter than previously suspected. The climate was suitable to support substantial vegetation — including stunted trees — along the edges of the frozen continent.
The team of scientists involved in the study, published online June 17 in Nature Geoscience, was led by Sarah J. Feakins of the University of Southern California in Los Angeles, and included researchers from NASA’s Jet Propulsion Laboratory in Pasadena, Calif., and Louisiana State University in Baton Rouge.
By examining plant leaf wax remnants in sediment core samples taken from beneath the Ross Ice Shelf, the research team found summer temperatures along the Antarctic coast 15 to 20 million years ago were 20 degrees Fahrenheit (11 degrees Celsius) warmer than today, with temperatures reaching as high as 45 degrees Fahrenheit (7 degrees Celsius). Precipitation levels also were found to be several times higher than today.
“The ultimate goal of the study was to better understand what the future of climate change may look like,” said Feakins, an assistant professor of Earth sciences at the USC Dornsife College of Letters, Arts and Sciences. “Just as history has a lot to teach us about the future, so does past climate. This record shows us how much warmer and wetter it can get around the Antarctic ice sheet as the climate system heats up. This is some of the first evidence of just how much warmer it was.”
Scientists began to suspect that high-latitude temperatures during the middle Miocene epoch were warmer than previously believed when co-author Sophie Warny, assistant professor at LSU, discovered large quantities of pollen and algae in sediment cores taken around Antarctica. Fossils of plant life in Antarctica are difficult to come by because the movement of the massive ice sheets covering the landmass grinds and scrapes away the evidence.
“Marine sediment cores are ideal to look for clues of past vegetation, as the fossils deposited are protected from ice sheet advances, but these are technically very difficult to acquire in the Antarctic and require international collaboration,” said Warny.
Tipped off by the tiny pollen samples, Feakins opted to look at the remnants of leaf wax taken from sediment cores for clues. Leaf wax acts as a record of climate change by documenting the hydrogen isotope ratios of the water the plant took up while it was alive.
“Ice cores can only go back about one million years,” Feakins said. “Sediment cores allow us to go into ‘deep time.'”
Based upon a model originally developed to analyze hydrogen isotope ratios in atmospheric water vapor data from NASA’s Aura spacecraft, co-author and JPL scientist Jung-Eun Lee created experiments to find out just how much warmer and wetter climate may have been.
“When the planet heats up, the biggest changes are seen toward the poles,” Lee said. “The southward movement of rain bands associated with a warmer climate in the high-latitude southern hemisphere made the margins of Antarctica less like a polar desert, and more like present-day Iceland.”
The peak of this Antarctic greening occurred during the middle Miocene period, between 16.4 and 15.7 million years ago. This was well after the age of the dinosaurs, which became extinct 64 million years ago. During the Miocene epoch, mostly modern-looking animals roamed Earth, such as three-toed horses, deer, camel and various species of apes. Modern humans did not appear until 200,000 years ago.
Warm conditions during the middle Miocene are thought to be associated with carbon dioxide levels of around 400 to 600 parts per million (ppm). In 2012, carbon dioxide levels have climbed to 393 ppm, the highest they’ve been in the past several million years. At the current rate of increase, atmospheric carbon dioxide levels are on track to reach middle Miocene levels by the end of this century.
High carbon dioxide levels during the middle Miocene epoch have been documented in other studies through multiple lines of evidence, including the number of microscopic pores on the surface of plant leaves and geochemical evidence from soils and marine organisms. While none of these ‘proxies’ is as reliable as the bubbles of gas trapped in ice cores, they are the best evidence available this far back in time. While scientists do not yet know precisely why carbon dioxide was at these levels during the middle Miocene, high carbon dioxide, together with the global warmth documented from many parts of the world and now also from the Antarctic region, appear to coincide during this period in Earth’s history.
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This research was funded by the U.S. National Science Foundation with additional support from NASA. The California Institute of Technology in Pasadena manages JPL for NASA.
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In case you are wondering (as I did) this is the orientation of the continents 20 million years ago during the Miocene period.
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What is really quite ridiculous about the AGW versus Denialist/Skeptic thing is that most of us are actually environmentalist. What we are fighting about on the skeptic sites here anyway is that CO2 is not causing any significant global warming. I have the feeling that many die hard “environmentalist” are now changing the story to sustainability etc due to overpopulation etc as it is realized that its not warming etc. Of course they will keep flogging the dead horse of Co2 until we all forget about it LOL
It’s a lie. They have tarnished the sanctity of “The Science”
Everyone knows that climate change means death. How could there have been pollen in Antarctica?
Halliburton or Bush or the Koch Brothers must have planted that pollen by directional drilling or fracking or drones or something. And now they’ve even got NASA in on the act.
Arrrghhhh! …..(gnashing of teeth)
/sarc
Alec Rawls says:June 18, 2012 at 6:22 pm
” While scientists do not yet know precisely why carbon dioxide was at these levels during the middle Miocene…”
Yes they do. They know it was high because the temperature was high. What they don’t know is why the temperature was high, and whether CO2 played a significant role as a cause as well as an effect.
We hear that our atmosphere is getting thinner. Could it have been thicker back then, where the adiabatic lapse rate would produce the higher temperature? It wouldn’t take much at 2 °C per thousand feet.
I agree that Ocean circulation and plate tectonics does come into play when you go back this far.
I think that the circum-Antarctic current was just getting started about 20 MY and that’s why there was global cooling after that time relative to before. There is also the closing off of the connection between the Atlantic & Pacific in the Americas that ended a current that would have eliminated that warming current.
“A new university-led study . . . finds ancient Antarctica was much warmer and wetter than previously suspected. The climate was suitable to support substantial vegetation . . . along the edges of the frozen continent;” “. . .15 to 20 million years ago were 20 degrees Fahrenheit (11 degrees Celsius) warmer than today . . .;”
Was this study conducted by graduate students or post docs from a different discipline? Their knowledge of what work was done before is severely lacking. Was there no academic lit search?
“This is some of the first evidence of just how much warmer it was.”
Dude, we already knew that. (Look up the work of Haq, Berggren, Bartek, Vail, Al-Fares, Al-Qahtani, and a dozen others for starters.) The Miocene Thermal Maximum had sea levels 150m higher than present. That condition was reached three times between 18mybp and 14mybp. (The polar ocean equivalent data suggest the max temp was closer to 9,5°C warmer than now, but that is ocean temps. Surface temps could have been warmer than that.) Major Antarctic re-glaciation didn’t happen until around 12.5mybp as the climate continued a protracted decline to reach colder-than-present conditions for the first time in the Cenozoic.
It is reprehensible for them to suggest that those conditions are at all relevant to what the climate is capable of in the near future. At the very least, the notion that CO2 levels now are approaching levels back then should demonstrate CO2 is not what is driving the climate and the recent high levels will not melt the West Antarctic Ice Sheet. We are no where near the warm conditions of any of the Pleistocene Interglacials. And those sea levels only reached 50m higher than present at their warmest, not the 150m of the Early and Middle Miocene.
“Back then” it appears that Florida was beneath the waves but 80% of Greenland was ice free. Some would consider this a win-win situation.
People may be interested in a 2006 study that also combined modelling with proxy data in order to estimate what contribution CO2 may have had to the climatic changes of that period.
http://www.earthbyte.org/people/dietmar/Pdf/Tong_etal_Miocene_climate_model_sensitivity_GPCinpress.pdf
gallopingcamel on June 18, 2012 at 9:51 pm said:
““Back then” it appears that Florida was beneath the waves but 80% of Greenland was ice free. Some would consider this a win-win situation.”
Now that is deeply offensive. Sure I don’t love it here all that much but to hear someone say such a thing about my State…wow.
it’s Bush’s fault
So Antarctica can warm by 7 C and not send the world past a tipping point of Venus proportions?
Good to know.
This is not new info. In fact, Antartica is known to have been even warmer during the Eocene, when forests were believed to have flourished within a hundred miles of the pole. The Miocene kinda marks the beginning of the long cold slip into the present condition (glacial/interglacial …..)
I’ve always wondered what the oceans would have been like worldwide when the poles were ice-free. Would the deep oceans have relatively warm water all the way to the bottom? (kind of like a glass of tea long after the ice had melted)
Just as history has a lot to teach us about the future, so does past climate.
Yes, it shows that there was no runaway warming, the land was more productive, and there’s nothing to fear if Antarctica were to lose ice.
Ah, the Miocene. The Garden Epoch. Forests from pole to pole, almost. The Earth teemed with life. Not too hot, not too cold. Green everywhere. The perfect climate. We can only hope and dream.
Warmer Is Better. Pass it on.
So what is suypposed to be new here? It has long been known that Antarctica was last partially ice-free in the Middle Miocene with tundra and Nothofagus beardmorensis scrub along the Ross Sea coast. It all froze up completely about 14 million years ago and has remained frozen ever since. This is just old knowledge regurgitated.
Here is a fascinating paper that describes the very last lacustrine fauna and flora that lived in the area, and have been preserved in a freeze-dried condition for 14 million years:
http://www.pnas.org/content/early/2008/08/01/0802501105.full.pdf+html
James Sexton says:
June 18, 2012 at 7:39 pm
I’ll go back and read for a bit, and check the supposed time frame, but all of these paleo studies…. the ones that go back millions or hundreds of thousands of years…. …. does the continental drift come into play on any of this?
Continental drift explains the coal deposits (yup, Antarctica has coal — wait’ll China finds out the Madrid Protocol banning mining in the Antarctic expires in 2041) and the dino fossils from the Cretaceous. Antarctica had already settled into its present location by the Miocene.
ummm.. brendan..
“not send the world past a tipping point of Venus proportions?”
At the same atmospheric pressures as those in Earth’s atmosphere, Venus is almost exactly the temperature it should be by the SB solar heating calculations. And Venus’s atmosphere is 96% CO2.. Obviously CO2 has very little effect on temperature.
Venus’s surface temps are due to the much larger atmospheric pressure.
I have an old photograph of grooves in a large sloping rock. I was told this was due to ancient glaciers. It seems that back in the time of Gondwanaland, some 200 million years ago, the South Pole was nearby. The photograph was taken in Southern Rhodesia, some 4,000 feet above sea level in the 1930s. What is now Antarctica would not have been under ice at that time.
‘ “The ultimate goal of the study was to better understand what the future of climate change may look like,” said Feakins, an assistant professor of Earth sciences at the USC Dornsife College of Letters, Arts and Sciences.’
Antarctica is awash with coal deposits, fossil evidence of beech forests, ferns and the like, and fossilised tree trunks (just ask the paleobotanists) and…… undoubtedly, oil…ask ‘big oil’. I’m struggling to grasp why it is that NASA consider their study insightful. It is true that a few may think of Antarctica as the fabled, interminable and immutable ice desert substantially bereft of animal and plant life as we know it but reality presents a different image, and this is well documented prior to NASA.
Sounds like a ‘job for the boys’ and the quest to remain relevant. The article summarises: “While scientists do not yet know precisely why carbon dioxide was at these levels during the middle Miocene, high carbon dioxide, together with the global warmth…”
Hmmmm…’do not yet know precise…’ = have absolutely no idea but spun up correctly guarantees money for more fun research in exotic places.
It may be worth mentioning that the Drake Passage was already about 20 million years old at the time this study refers to, so I don’t think it can be a factor in the temperature variation there.
Ted says:
June 18, 2012 at 6:21 pm
The Warmist will never except that modern climate conditions can be as variable and changing as it always has,
————–
Why doesn’t Ted just ask instead of fantasizing?
Simple question: hey mr warmista, do you believe climate conditions can be highly variable?
John says:
June 18, 2012 at 7:20 pm
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Why do we have to avoid sea levels substantially higher than today?
Even if sea defences are not able to restrain the ingression, there is plenty of land on planet Earth, and there still will be plenty of land even if sea levels are substantially higher. Indeed new areas of land will open up such as the Antarctic.
As long as sea level rise is relatively slow, we (and other living things) will simply migrate inland as the sea levels rise. There will be no big problem.
The threat posed by sea level rise is over-stated, and this is a good thing since it may well be the case that we cannot control sea level rise as it is a function of natural variation and not dependent upon the extent of manmade CO2 emissions. .
Mike Dubrasich says:
June 18, 2012 at 11:41 pm
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Certainly for mankind. As an animal species, we would greatly benefit from the planet being 5 to 8 degC warmer than today.
Given the present cool conditions on planet Earth, if it were not for our skill of adaption, our natural habitat as a species would be restricted to the tropical rain forests, the outback of Australia and a few other similar places. We certainly would not be inhabiting much of of the Northern hemisphere.
Air-bubbles in icecores are only a reliable source of the CO2-content in ancient athmophere if you believe in AGW-theory
AndyG55 says:
June 19, 2012 at 12:48 am
ummm.. brendan..
“not send the world past a tipping point of Venus proportions?”
At the same atmospheric pressures as those in Earth’s atmosphere, Venus is almost exactly the temperature it should be by the SB solar heating calculations. And Venus’s atmosphere is 96% CO2.. Obviously CO2 has very little effect on temperature.
Venus’s surface temps are due to the much larger atmospheric pressur
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Thanks Andy.
I was being slightly facetious. It always seems that when I discuss this issue with my environmental friends, who think science is done by press release, they always seem to raise Venus as an example of where the world will end up if we don’t stop our evil ways.
Considering they have iphones, ipads and all the other constantly connected popular gadgets (which I find quite ironic) it astounds me just how uninformed they are.
The Antarctic peninsular was covered by trees during the Cretaceous, evergreens like pines, but most of the peninsular is north of the Antarctic Circle so still gets a small portion of winter sun. Fairly important if you are a plant. All the research I have seen confirms that the main landmass of Antarctica was ice bound despite higher temperatures and sea levels though there may have been melting along the coast during summer in places.