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Global warming means palm trees could return to Antarctica

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 Global warming means palm trees could return to Antarctica  Empty Global warming means palm trees could return to Antarctica

Post by Birugalli Fri Aug 03, 2012 6:24 pm

Global warming means palm trees could return to Antarctica

If the continent becomes warm again,sea levels could rise 60 metres,swamping coastal cities such as New York,Sydney and Hong Kong


Palm trees swayed on the green shores of Antarctica 50 million years ago while temperatures soared above 20C,a study has shown.The discovery provides a startling glimpse of what might be in store for the world in centuries to come if global warming continues unchecked.If Antarctica ever became as warm again,sea levels could rise 60 metres (197 feet),swamping major coastal cities such as New York,Sydney and Hong Kong.Scientists drilled a kilometre into the ocean floor to collect samples of fossilised pollen that have lain undisturbed for millions of years.
They revealed a vastly different version of Antarctica than exists today.During the Eocene epoch,between 48 and 55 million years ago,high levels of greenhouse gas in the atmosphere forced up temperatures.
The UK was,on average,15C warmer than it is today and a steaming rainforest covered the site of London.
But the most dramatic effect of the Eocene 'greenhouse world' was seen at the poles,according to the new evidence.
Detailed examination of fossilrich Antarctic sediments has not been possible before,since any remaining on land have been destroyed by glaciation or buried under thousands of metres of ice.The new research involved an expedition to drill off Wilkes Land on the east coast of Antarctica.
Members of the 2010 Integrated Ocean Drilling Research Programme dropped a string of drill pipes through four kilometres of water to bore into the ocean floor.
Dr James Bendle,from the University of Glasgow,said: The Eocene sediment samples are the first detailed evidence we have of what was happening on the Antarctic during this vitally important time.
We conducted the drilling expedition against a backdrop of freezing temperatures,huge ocean swells,calving glaciers,snow-covered mountains and icebergs.

Its amazing to imagine a time traveller,arriving at the same coastline in the early Eocene,could paddle in pleasantly warm waters lapping at alush forest.'

Pollen from plants living in two different environments were found in the sediment cores.
One was a lowland,warm rainforest,dominated by tree-ferns,palms and trees belonging to the bombacaceae family.

Modern bombacaceae include the baobab tree of Madagascar,also known as the tree of life because it holds water in its thick trunk.

The other environment was an upland,mountain forest region with beech trees and conifers.
Pollen from both regions would have been washed,blown or transported by insects onto the shallow coastal shelf.

Here,it settled in the mud and was preserved for 50 million years.
The pollen shows that average Eocene temperatures on the Antarctic coast were around 16C and summers reached a balmy 21C,the scientists reported in the journal Nature.

Dr Bendle added: Our work carries a sobering message.Carbon dioxide levels were naturally high in the early Eocene,but today CO2 levels are rising rapidly through human combustion of fossil fuels and deforestation.We havent reached Eocene levels yet but we are increasing at arate faster than any time in Earths history.

Atmospherically speaking,we are heading rapidly back in time towards the Eocene.Already CO2 levels are at a peak not seen since the Pliocene warm period 3.5 million years ago.The biggest threat lies in the fact that Antarctica today is covered with ice,enough to potentially raise global sea-levels by 60 metres if the continent once again reaches Eocene temperatures,which would have devastating effects all over the world.'
Lead author Professor Jvrg Pross,from Goethe University in Frankfurt,Germany,said: If the current CO2 emissions continue unabated due to the burning of fossil fuels,CO2 concentrations in the atmosphere,as they existed in the distant past,are likely to be achieved within a few hundred years. AGENCIES
Birugalli
Birugalli

Posts : 19
Join date : 2012-07-16

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