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Antarctica’s warmer past revealed


With an uninterrupted 17-million year sediment record of Antarctic’s climatic past now available, scientists are hoping for unique new insights into the continent’s climatic past.

A few initial results of the Antarctic Geological Drilling programme (ANDRILL) were announced last week at the general assembly of the European Geosciences Union in Vienna. There is an online news story here.

Antarctica’s ice sheets, so it seems, respond more sensitively to climate fluctuations than has been assumed. During warmer periods, the West Antarctic Ice Sheet and its floating extension, the western Ross Ice Shelf, have shrunk substantially. Some 3.5 million years ago the ice seems to have disappeared completely for around 200,000 years. There were snow-capped mountains, alpine trees, gushing rivers, quiet lakes – the frozen continent was a place where you would love to go fishing or hiking, were it not for the midges.

The world was warmer then than it is today, but not substantially so. If temperatures continue to rise, glaciers in Antarctic’s warmer western part might begin to retreat again before long. A few million years ago, Antarctic melting probably raised sea levels globally by 10 metres or so. If history repeats itself, we’re headed for trouble.

Quirin Schiermeier


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    Larry Sheldon said:

    Don’t “we” (meaning people who actually know something about what they are talking about, which might not include me) think that Antarctica was once part of Pangaea (or some such thing) way north of the South Pole?

    How do the coreings relate (time-wise) to the Pangaea thing?

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    Quirin Schiermeier said:

    Pangaea began to break apart some 150 million years ago. The ANDRILL cores cover a period (0-17 million years ago) when Antarctica had long reached its current polar position.

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    Holly said:

    With all the trouble that such an increase in sea levels might bring it seems that the climate changes were not really influenced my man made activities so I wonder what would the next step mean in the climate research

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    Leif Skovbo said:

    To Larry Sheldon:

    Pangaea existed for 250 mio years ago. So for 3.5 mio years ago the landmasses would look somewhat like that of today.

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    Timo said:

    “The world was warmer then than it is today, but not substantially so.”

    I assume you actual mean this part of the world was substantially warmer than it is today. If all ice from Antartica had disappeared, this would imply a substantial temperature increase in that part of region, but maybe also the rest of the world. Thus this mean that other regions in the world (e.g. the tropocial region or Europe for example) would also be (substantially) warmer than today?

    It will be interesting to see what the final result of th research will be.

    Another explanation; volcanic activity in that part of the region? However, that doens’t really explain the lack of ice for 200.000 years or more.

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