Temperatures of sea water fringing South Pole were tropical 50 million years ago

Oct 08, 2009
Earth

(PhysOrg.com) -- The temperature difference between equatorial and polar sea waters was minimal during the extremely warm 'Greenhouse world' 60 to 50 million years ago. This is the main conclusion drawn by a team of scientists from Utrecht University, the Netherlands, the NIOZ Royal Netherlands Institute for Sea Research and the University of California, Santa Cruz. The team of scientists, headed by Peter Bijl, show that circum-Antarctic sea water exceeded 30ºC at that time. The results were published in Nature this week.

The conclusions are based on analyses on sediments retrieved from the ocean floor east of Tasmania. This area bordered to Antarctica during the early Paleogene (60-35 milion years ago). Much research is focused on polar areas, because these are particularly sensitive to climate change.

Previously, scientists from Utrecht University and the Royal NIOZ presented in a suite of Nature and Science articles the manifestation of Greenhouse climates in the Arctic regions, with the invasion of tropical algae and sea surface temperatures of up to 24ºC. Meanwhile, temperatures of waters fringing the Antarctic continent during the Greenhouse climates were a great unknown to climate scientists. The multidisciplinary research, published in Nature, now reached a breakthrough.

What emerges from these results is that the Greenhouse pole-to-equator gradient was close to non-existent. After the warmest phase (about 50 million years ago), the world gradually cooled down to an ‘Icehouse’ state, like today. Along with this cooling, the temperature gradient turned more and more into its present day shape.

The interest to society is evident: the fossil Greenhouse world is generally considered to be a potential analogue for future climates. “The fossil Greenhouse world of 50 Million years ago is generally considered analogous to future climates”, says Peter Bijl, paleo-climatologist at Utrecht University. “These field data imply that polar temperatures can be much higher than the IPCC computer models predict for a high-CO2 world. In turn, change can be even more severe than the worst case scenario’s of the IPCC.”

More information: Letter in Nature: Early Palaeogene Temperature evolution of the Southwest Pacific Ocean, by Peter K. Bijl, Stefan Schouten, Appy Sluijs, Gert-Jan Reichart, James C. Zachos and Henk Brinkhuis.

Provided by Utrecht University (news : web)

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User comments : 8

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omatumr
3 / 5 (7) Oct 08, 2009
Congratulations!

Until we better understand past variations in Earth's climate, we cannot possibly predict its future.

It is refreshing to see quantitative research results instead of the empty hand waving that has plagued claims of CO2-induced global warming.

With kind regards,
Oliver K. Manuel
GrayMouser
3 / 5 (4) Oct 08, 2009
The interest to society is evident: the fossil Greenhouse world is generally considered to be a potential analogue for future climates.

As long as they remember that the CO2 levels went up AFTER the temperature went up. Not before!
Nartoon
2.3 / 5 (3) Oct 09, 2009
No matter which came first it certainly wasn't driven by AGW.

"Much global warming research is focused on polar areas, because these are particularly sensitive to climate change."

Funny how, other than reporting shrinking ice levels in the north, and NOT REPORTING growing ice levels in the south, almost every claim for AGW has nothing to do with the poles.
pankratz
Oct 09, 2009
This comment has been removed by a moderator.
Snowhare
1 / 5 (3) Oct 09, 2009
Funny how, other than reporting shrinking ice levels in the north, and NOT REPORTING growing ice levels in the south, almost every claim for AGW has nothing to do with the poles.


The last time CO2 levels were this high was 15 million years ago. The Arctic was ice free and the Antarctic was nearly so. Sea level was 75 to 120 feet higher than it is today as a direct consequence. http://newsroom.u...074.aspx

There is no record of CO2 levels _ever_ being this high when similar conditions _did not_ prevail.

We've lit the fuse by pumping (and continuing to pump) CO2 into the atmosphere in massive quantities. AGW is not merely inevitable at this point, it is clearly already in progress. Sea level is rising, ice cover is declining, global mean temperatures are rising.

Study after study continues to confirm that not only is AGW real, it is very likely to be ultimately be worse than we projected even a few years ago.
Docrings
3 / 5 (2) Oct 10, 2009
The sooner man realizes he cannot change the forces of nature, and learns to build and live in harmony with the changes, the better off we'll be as a whole.

Better to spend much of that money on technologies to ADAPT to the natural changes, not in a gamble to stop it. And some of that money should be put to underwriting low CO2 energy production, not to slow global warming, per se, but because of reduced pollution to our health and reduced foreign energy dependence and the subsequent wars (and death) that ensues from that.

That doesn't mean we can't enact policies for fair and clean energy usage, and to be smart about progressive use of electric vehicles, solar/wind/nuclear energy... we should do these things because it is a good thing to not be dependent on foreign energy sources, not because we think we can stop the Earth from continuing its warming trend in any signficant way.
GrayMouser
1 / 5 (1) Oct 12, 2009
The last time CO2 levels were this high was 15 million years ago.

And if you go back farther you will find that the CO2 levels have been 10 times higher than now. So what?

The Arctic was ice free and the Antarctic was nearly so. Sea level was 75 to 120 feet higher than it is today as a direct consequence.

Of the ice melting, yes. Of the CO2 levels... No conclusion is possible.

Study after study continues to confirm that not only is AGW real, it is very likely to be ultimately be worse than we projected even a few years ago.

And study after study confirm that is is not real. And ever since it started cooling the predictions have gotten more dramatic.
Snowhare
not rated yet Oct 12, 2009
And if you go back farther you will find that the CO2 levels have been 10 times higher than now. So what?


When CO2 levels were 10 times higher, the planet was 30 degrees C warmer. You aren't helping yourself.

The Arctic was ice free and the Antarctic was nearly so. Sea level was 75 to 120 feet higher than it is today as a direct consequence.

Of the ice melting, yes. Of the CO2 levels... No conclusion is possible.


Saying it doesn't make it true. When you actually look at the history of CO2 and temperature over the history of the earth the conclusion that high CO2 and high temperatures go together is inescapable.

Study after study continues to confirm that not only is AGW real, it is very likely to be ultimately be worse than we projected even a few years ago.

And study after study confirm that is is not real.


Name the studies.

And ever since it started cooling the predictions have gotten more dramatic.


It isn't cooling.
MartyBvanS
not rated yet Oct 22, 2009
How about between 12 and 14,000 years ago?