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Antarctica's tropical past is revealed

Posted: Thu Aug 02, 2012 9:14 pm
by edfrank
Antarctica's tropical past is revealed
From: Marion O'Sullivan, Planet Earth Online
Published August 2, 2012 08:17 AM

http://planetearth.nerc.ac.uk/news/stor ... eConsent=A


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The researchers took a research ship to Wilkes Land off Antarctica's eastern coast, where they drilled a kilometre deep into the ocean floor. The layers of sediment they extracted contain tiny fossils and chemicals, trapped in a snapshot of time.

Dr James Bendle from the University of Glasgow was one of the team who took part in the study. He says, 'In the sediments we found fossilised pollen representing two distinct environments with different climatic conditions - a lowland, warm rainforest dominated by tree-ferns, palm trees and baobab trees; and a cooler mountainous region dominated by beech trees and conifers.'
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Re: Antarctica's tropical past is revealed

Posted: Thu Aug 02, 2012 10:45 pm
by edfrank
Antarctica Was Once Home To Rainforest, Say Scientists
Posted: 08/02/2012 2:52 pm Updated: 08/02/2012 2:52 pm

http://www.huffingtonpost.com/2012/08/0 ... mg00000040
Scientists drilling off the coast of Antarctica made a startling discovery recently that could hold clues to the Earth's future -- especially if climate change keeps warming the planet.

According to a study published in the journal Nature, the frozen continent was home to a "near-tropical" rainforest 52 million years ago, when temperatures measured about 68 degrees Fahrenheit.
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Re: Antarctica's tropical past is revealed

Posted: Fri Aug 03, 2012 6:37 am
by Joe
But.... regarding that tropical Antartica- where was it at the time? It probably wasn't at the bottom of the planet. The problem with this is that the GW Deniers will probably say, "see, nothing wrong with a warmer climate"- of course it was warmer, everywhere back then and when there were no humans, it didn't make much difference how the climate changed- but now with much of the human population close to the sea, rapid climate change will be horrific...

I'm sure geologists know exactly where it was back then- I'm surprised the articles don't mention this- it must have been in the original research paper and that fact is significant- because a warmer climate ain't gonna turn Antartica tropical, not where it is, anyways.
Joe

Re: Antarctica's tropical past is revealed

Posted: Fri Aug 03, 2012 8:10 am
by edfrank
Joe,

During the Eocene warm period Antarctica was basically the same place it is today. it was in the antarctic with the bulk of the continent within the Antarctic circle. The big difference was that Australia blocked much of the southern ocean and kept the cold ocean circulation from just whipping around the continent.


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Ed

Re: Antarctica's tropical past is revealed

Posted: Fri Aug 03, 2012 8:30 am
by Joe
OK, kind of amazing that it could still have tropical vegetation that far south- though I suspect it was only in some areas, not in the interior.
Joe

Re: Antarctica's tropical past is revealed

Posted: Wed Aug 08, 2012 12:22 pm
by KoutaR
Ed & Joe,

Researchers probably exaggerate when they say "tropical Antarctica". I have read a bit about the natural history of Australia, and most researchers seem to admit the climate in southern Australia (which was close to Antarctica in that time) was rather subtropical than tropical. Also the temperatures, the first article gives, are not tropical but even temperate (>10 - 21°C).

Ed, do you know what are the most probable reasons for the temperature rise in the late Palaeocene? "A Natural History of the New World" by Alan Graham gives an explosive emission of methane from the Norwegian Sea as the only possible reason, but I have read from some Internet sites that it is only one theory among others.

Kouta

Re: Antarctica's tropical past is revealed

Posted: Wed Aug 08, 2012 6:35 pm
by Jess Riddle
Kouta,

The one Paleocene-eocene thermal maximum researcher I’ve spoken with seemed fairly certain that release of methyl clathrates from continental shelf areas precipitated that warming event. However, she indicated it was not known what released the methyl clathrates.

Jess