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The ice caps : more than 4 000 m thick A Mont Blanc of Ice ! 4,800 metres of ice on the southern continent! A Mont Blanc made entirely of ice! How did such an accumulation come to be formed? How long did it take?
Despite numerous scientific studies that are beginning to understand the phenomena linked to the rate of accumulation of the ice, these questions are still not totally answered. "How can one explain changing from the moderate and uniform climate that existed 60 million years ago on Earth" writes the French glaciologist Claude Lorius in his book "Antarctic Ice, One Memory, Many Passions" "to the geographically contrasted climate that we know today and since the beginning of the ice age of the Quaternary period? Part of the answer will doubtless come from the Antarctic."
What is known for certain, on the other hand, is that the Antarctic ice is the oldest ice in the world. Older than the eternal snows of the Himalayas, older than the Greenland or Arctic ice caps, older than the Alpine glaciers; the glaciation of the white continent is estimated to date from at least 20 million years.
Knowing that the freeze is permanent there, it could be said that during this time the snow fall had comfortably had the time to transform itself into layers of ice. The thickness of the latter is however not the same everywhere. Because the mass of moist air coming from the oceans rarely crosses the immensity of the continent, it snows less at the interior of the Antarctic than at its edges; 5 centimetres in the centre of the continental glacier as opposed to 65 centimetres at the coasts are the most frequently mentioned figures. To have an idea of the weight of this accumulation, an astronomical figure is regularly put forward: 2,000 billion tons of snow is thought to fall on the Antarctic each year, or an average of 15 grams per square centimetre.
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