From Yale University, where that means that even though Earth 40-50 million years ago had a completely different arrangement of continents and climate, it still somehow will “underscore the potential for increased warmth at Earth’s poles and the associated risk of melting polar ice and rising sea levels”. Note that in this paleoreconstruction below, there is still a southern ice cap.
![SIA3657[1]](http://wattsupwiththat.files.wordpress.com/2014/04/sia36571.jpg?quality=83)
The PR reads: Parts of ancient Antarctica were as warm as today’s California coast, and polar regions of the southern Pacific Ocean registered 21st-century Florida heat, according to scientists using a new way to measure past temperatures.
The findings, published the week of April 21 in the Proceedings of the National Academy of Sciences, underscore the potential for increased warmth at Earth’s poles and the associated risk of melting polar ice and rising sea levels, the researchers said.
Led by scientists at Yale, the study focused on Antarctica during the Eocene epoch, 40-50 million years ago, a period with high concentrations of atmospheric CO2 and consequently a greenhouse climate. Today, Antarctica is year-round one of the coldest places on Earth, and the continent’s interior is the coldest place, with annual average land temperatures far below zero degrees Fahrenheit.
But it wasn’t always that way, and the new measurements can help improve climate models used for predicting future climate, according to co-author Hagit Affek of Yale, associate professor of geology & geophysics.
“Quantifying past temperatures helps us understand the sensitivity of the climate system to greenhouse gases, and especially the amplification of global warming in polar regions,” Affek said.
The paper’s lead author, Peter M.J. Douglas, performed the research as a graduate student in Affek’s Yale laboratory. He is now a postdoctoral scholar at the California Institute of Technology. The research team included paleontologists, geochemists, and a climate physicist.
By measuring concentrations of rare isotopes in ancient fossil shells, the scientists found that temperatures in parts of Antarctica reached as high as 17 degrees Celsius (63F) during the Eocene, with an average of 14 degrees Celsius (57F) — similar to the average annual temperature off the coast of California today.
Eocene temperatures in parts of the southern Pacific Ocean measured 22 degrees Centigrade (or about 72F), researchers said — similar to seawater temperatures near Florida today.
Today the average annual South Pacific sea temperature near Antarctica is about 0 degrees Celsius.
These ancient ocean temperatures were not uniformly distributed throughout the Antarctic ocean regions — they were higher on the South Pacific side of Antarctica — and researchers say this finding suggests that ocean currents led to a temperature difference.
“By measuring past temperatures in different parts of Antarctica, this study gives us a clearer perspective of just how warm Antarctica was when the Earth’s atmosphere contained much more CO2 than it does today,” said Douglas. “We now know that it was warm across the continent, but also that some parts were considerably warmer than others. This provides strong evidence that global warming is especially pronounced close to the Earth’s poles. Warming in these regions has significant consequences for climate well beyond the high latitudes due to ocean circulation and melting of polar ice that leads to sea level rise.”
To determine the ancient temperatures, the scientists measured the abundance of two rare isotopes bound to each other in fossil bivalve shells collected by co-author Linda Ivany of Syracuse University at Seymour Island, a small island off the northeast side of the Antarctic Peninsula. The concentration of bonds between carbon-13 and oxygen-18 reflect the temperature in which the shells grew, the researchers said. They combined these results with other geo-thermometers and model simulations.
The new measurement technique is called carbonate clumped isotope thermometry.
“We managed to combine data from a variety of geochemical techniques on past environmental conditions with climate model simulations to learn something new about how the Earth’s climate system works under conditions different from its current state,” Affek said. “This combined result provides a fuller picture than either approach could on its own.”
The paper is titled:
Pronounced zonal heterogeneity in Eocene southern high-latitude sea surface temperatures.
Significance
Reconstructions of ancient high-latitude climates can help to constrain the amplification of global warming in polar environments. Climate models cannot reproduce the elevated high-latitude temperature estimates in the Eocene epoch, possibly indicating problems in simulating polar climate change. Widely divergent near-Antarctic Eocene sea surface temperature (SST) estimates, however, question the evidence for extreme warmth. Our analysis of multiple temperature proxies near the Antarctic Peninsula improves intersite comparisons and indicates a substantial zonal SST gradient between the southwest Pacific and South Atlantic. Simulations of Eocene ocean temperatures imply that the formation of deep water in the southwest Pacific partly accounts for this SST gradient, suggesting that climate models underestimate Eocene SSTs in regions where the thermohaline circulation leads to relatively high temperatures.
Abstract
Paleoclimate studies suggest that increased global warmth during the Eocene epoch was greatly amplified at high latitudes, a state that climate models cannot fully reproduce. However, proxy estimates of Eocene near-Antarctic sea surface temperatures (SSTs) have produced widely divergent results at similar latitudes, with SSTs above 20 °C in the southwest Pacific contrasting with SSTs between 5 and 15 °C in the South Atlantic. Validation of this zonal temperature difference has been impeded by uncertainties inherent to the individual paleotemperature proxies applied at these sites. Here, we present multiproxy data from Seymour Island, near the Antarctic Peninsula, that provides well-constrained evidence for annual SSTs of 10–17 °C (1σ SD) during the middle and late Eocene. Comparison of the same paleotemperature proxy at Seymour Island and at the East Tasman Plateau indicate the presence of a large and consistent middle-to-late Eocene SST gradient of ∼7 °C between these two sites located at similar paleolatitudes. Intermediate-complexity climate model simulations suggest that enhanced oceanic heat transport in the South Pacific, driven by deep-water formation in the Ross Sea, was largely responsible for the observed SST gradient. These results indicate that very warm SSTs, in excess of 18 °C, did not extend uniformly across the Eocene southern high latitudes, and suggest that thermohaline circulation may partially control the distribution of high-latitude ocean temperatures in greenhouse climates. The pronounced zonal SST heterogeneity evident in the Eocene cautions against inferring past meridional temperature gradients using spatially limited data within given latitudinal bands.
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That’s old news. I read a report 20 years ago they found dinosaur fossils under 10,000 feet of ice. The Med Sea was a desert 5 million years ago.
Someone didn’t do their pre-research, literature research and abstract research to Sherlock Holmes detail.
Isotope studies tell a different story.
http://oi57.tinypic.com/10ohdtk.jpg
http://www.wgsr.uw.edu.pl/uploads/f_biblioteka/PIS/47/Boryczka.pdf
Hm.. as Paul Pierett say above That’s old news” I am 64 years old. When I was in 6th grade long ago that’s was to be read in books we had….
Bye the way – under the ice sheet there is a large sea with open water….
When do they ever learn? The so called experts and scholars of today…
Does not apply to now because the Antarctic ice sheet is a record.
http://arctic.atmos.uiuc.edu/cryosphere/antarctic.sea.ice.interactive.html
Antarctica was part of Gonnawana land before the continents separated. Sorry about the spelling, I am tired. And it ain’t news.
Chill Man!
Antarctica was hot now it’s cool.
Its just drift in around.
I see that their earth has zero axis tilt back then; and of course all the land masses are in different places.
They don’t say what the Temperatures were like back then in California, and Florida.
When earth gets back to those conditions, we will probably have to live in some different places.
I don’t mind moving.
Nyquist is having an epileptic seizure, while contemplating their global sampling methodology.
Hmmmmm… Perhaps that piece of Earth’s crust where they took the shell samples was positioned in a warm area of the globe 60 million years ago, but the real question is WHERE was that piece of crust located 60 million years ago….
If it was located on the same latitude as Brazil is now, who cares?….
Paleoclimatology research, like real estate, is all about three things: location, location, location. If it’s in the wrong location, it isn’t worth much…
And the taxpayers funded this.
“Led by scientists at Yale, the study focused on Antarctica during the Eocene epoch, 40-50 million years ago, a period with high concentrations of atmospheric CO2”
That raises the matter of how much was the latter actually so. For instance, Pearson et al 1999 has calculated from proxy data that CO2 during the mid Eocene (sampling 43 million years ago) was only 370 to 400 ppm (best estimate, with the data judged to constrain it to somewhere between 170ppm and 570ppm): http://www.geol.umd.edu/~kaufman/ppt/G436/G436_PDF_library/Pearson_99.pdf
Additionally, separate from the CO2 level in itself is the matter of whether it was more a consequence of the temperature than a temperature driver, with warmer oceans outgassing more (and influenced by other factors like volcanic activity).
Pearson et al. also remark:
“If our estimate of middle Eocene pCO2 is correct, then it implies either that Earth’s climate is very sensitive to small changes in pCO2, or that the global cooling since the Eocene was not driven primarily by changes in pCO2, but rather reflects reorganization of ocean circulation resulting from tectonic opening and closing of oceanic gateways (2).”
Of course, the former scenario doesn’t fit other evidence, such as how going from pre-industrial levels of CO2 to the 400 ppm of CO2 now hasn’t caused more than low tenths of a degree temperature change at most (since the bulk of warming since the LIA is already explainable by another cause far better matching its pattern).
I do not quite see why the warm poles 50Ma ago prove it could happen today. The continents are completely different with totally different ocean currents. Look at the map they provide above.
It does show that Plate Tectonics are a climate driver, though slower than sunshine.
If the atmospheric CO2 content fell below 200ppmv all plant life would hav e died out. This did not happen so my bet is that the CO2 levels were well above this figure.
CO2 DOES NOT DRIVE CLIMATE.
A long time ago, Someone I knew was involved with a software migration project. When they finished the specification for the next item, They were told to delete the work and start again. The whole project was a massive ripoff.
Can’t think of why this paper reminds me of that project.
“the Eocene epoch … a period with high concentrations of atmospheric CO2 and consequently a greenhouse climate”
So, water vapour was not a greenhouse gas back then?
Paul Pierett says:
April 22, 2014 at 12:07 am
“That’s old news. […]”
===============================
Ahhh, good ol’ WUWT commenters. Paul got it in the first comment and in the first three words.
Who’s to blame the researchers for taking advantage of the fact that the people approving grant applications don’t do any extensive literature search, if they search at all?
Was the climate warmer because of CO2, or was CO2 more abundant because it was warmer
The main issue as always is with the assumption that higher CO2 caused higher temperatures rather than higher CO2 caused by the higher temperatures that existed between the end of the Paleocence (65 to 55 MY) and the beginning of the Eocene (55 to 35 MY). Natural CO2 increase follows temperature not the reverse as demonstrated by ice cores in the longer-term and also at shorter time periods. In much of the Eocene there was a cooling trend. Also although during the Paleocene/Eocene periods the Antarctica continent was well separated from a Gondwanaland and therefore Australia and had its southern part within the south pole region, its northern part extended further north than the present Antarctic circle at latitude 66.59 degrees south of the equator.
The key parts of the PR:
“… the new measurements can help improve climate models used for predicting future climate… Quantifying past temperatures helps us understand the sensitivity of the climate system to greenhouse gases, and especially the amplification of global warming in polar regions…”
AND
“…the study focused on Antarctica during the Eocene epoch, 40-50 million years ago, a period with high concentrations of atmospheric CO2 and consequently a greenhouse climate…”
Even that outstanding climate physist journal, Mother Earth, had this to say about the area studied
http://elainemeinelsupkis.typepad.com/earth_news/2006/04/antarctica_froz.html
While minor events like volanoes, rifting, continents moving from North to South, the oceans in what must have been near castrophic changes, the science boys and girls alwasy imply CO2 and greenhouse gases are major drivers. CO2 has evolved, just like Baal of ancient times as the great weather god of Western (Political) Science.
And, if, as phillipbratby said at April 22, 2014 at 1:52 am. “And the taxpayers funded this”, emmense offerings are made by everyone, to the CO2 god.
Yale are a bit slow of the mark.
http://www.belspo.be/belspo/bepoles/file/459.pdf
Back at the turn of the century 20th century Shackleton on his expedition to the Antarctic found seams of coal, impressions of leaves in sandstone boulders and fossilized wood from coniferous trees.
I couldn’t help but notice their map has a little England and ireland off the coast of proto-europe; even though it’s now agreed that the English Channel wasn’t carved out until the end of the last ice age, about 12K years ago.
The Antarctic only became fully ice covered at the end if the Eocene and into the Oligocene when it was split away from South America and the circum-Antarctic currents developed. This isolated Antarctica and allowed the major cooling. It was tectonics and nothing much else.
“Led by scientists at Yale, the study focused on Antarctica during the Eocene epoch, 40-50 million years ago, a period with high concentrations of atmospheric CO2 and consequently a greenhouse climate.“. A comment on the Middle Eocene Climatic Optimum (MECO) noted “ just how large the natural buildup of atmospheric CO2 may have been—as much as 50 times modern levels. Yet even at these levels Earth was still quite livable.“.
http://theresilientearth.com/?q=content/co2-temperature-during-middle-eocene-climatic-optimum
’50 times’ is well over five doublings.
“This provides strong evidence that global warming is especially pronounced close to the Earth’s poles.“. Like antarctica close to the South Pole today?
@bushbunny – People forget that the continents were not always in the exact position they are today. And someone posted a short video showing what they would be like in another 100 million years (I doubt man will be wise enough to still be around then).
So there may have been ice caps during the Eocene. But Antarctica was not under them.
Where landmass used to be:
http://www.scotese.com/earth.htm
temperature and CO2 over the long term:
http://i46.tinypic.com/2582sg6.jpg
This is a much better illustration of Antarctica circa about 45 million years ago.
http://cdn.phys.org/newman/gfx/news/hires/2014/1-iconicaustra.jpg
But I don’t think Antarctica was quite at the south pole then, even though all the reconstructions have it not quite in its current position but close. It had to be more like 2000 kms to the northwest, going by the location of the mid-oceanic ridge between Antarctica and Australia/Tasmania. Its just something that I think cannot be ignored. It is factual evidence.
The other issue is what were the ocean currents doing then? There was no Antarctic circumpolar current. Just the large ocean gyres which would have brought warm water from the tropics to Antarctica.
The ocean currents and continental positions about 45 million years ago.
http://img35.imageshack.us/img35/8862/antoceancurrents35m.jpg
This is an in-depth description/chart of temperature and geography over the last 45 million years.
http://s22.postimg.org/804qp4xo1/Temp_Geography_45_Mys.png
Was Antarctica warmer then? Yes, trees grew there and some marsupials lived in Antarctica at the time (Australia and South American cousins). But it still had six months of darkness. Reasonably warm summers (above 0.0C certainly) but it was extremely cold in the six months of dark winter at the pole.
When Australia and South America separated from it just enough so that the ocean was about 400 metres deep (it could take tens of millions of years for this to occur after an initial separation), the Antarctic Circumpolar Current started up, exactly at 33.6 million years ago. Within 75,000 years, Antarctica became nearly completely glaciated over and all the plants and animals were gone.