Antarctica (Horizon)

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2 Cover
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[edit] General Information

Nature, Science Documentary hosted by Jo Unwin and published by BBC broadcasted as part of BBC Horizon series in 1997 - English narration

[edit] Cover

[edit] Information

Antarctica's polar ice sheet is the highest, coldest, windiest, driest and most unforgiving place on earth. Dry as the Sahara Desert with less than 5cm of snow a year it is also numbingly cold.

The average temperature near the South Pole is minus 49 degrees Centigrade, and winds reach over 200Km an hour.

[edit] The Ice Lives

Craig MacClean is a Beach Boys fan, he likes hanging out in the California sun, and drinking the odd beer at a football game. But this winter he'll be in Antarctica working as chief of medical supplies in McMurdo General Hospital.

Water in a liquid form, the essence of life, is scarce. Yet this inhospitable continent has now become the last frontier on earth - and each year a population of 3,000 colonists try to settle here.

The success of life in a landscape as alien as any on this planet is a biological aberration.It hints at the possibility of extra-terrestrial life as it provides intriguing insights into the limits of living systems.

This is why many of the human visitors are biologists. They study the Penguins, the seals and the nematodes - the few other higher life forms that also survive the winter here - to try and discover how it is they have adapted to life in the freezer. But it is also why the scientists, support staff and the armed forces that make up the colonial population of Antarctica are themselves under investigation.

Craig Maclean is just one of thirty subjects - part of a human experiment that is finding out what happens to Homo sapiens on ice.

[edit] The Ice Forms

The Beardmore Glacier was the crevasse-riddled route Scott and Shackleton man-hauled up to the South Pole. It provided the most direct route from the coast, over the Transantarctic Mountains onto the vast flat waste of the Polar Plateau and to the South Pole.

Today it is flown over by the latest generation of Antarctic heroes and it is also providing the hints and clues that may explain how this continent formed.

Antarctica is just a tiny fragment of one of the biggest continents that has ever existed: Gondwanaland. It sits alone, fixed at the South Pole, while the land-masses that used to be part of it have floated off to form the other great continents of South Africa, India, Australia and South America.

Geologists always believed that this process of fragmentation was driven by rifting - the usual course of plate tectonics pushing continents apart. And glaciologists completed the story of Antarctica's formation by arguing that the separation of Antarctica from New Zealand led to the creation of a circular current in the Southern Ocean.

It was this that supposedly led to the continent becoming cold about 18 million years ago. Yet in the last decade discoveries emerging from the continuing exploration of Antarctica have challenged this view.

Following in the Footsteps of Scott, the journeys of British, American and New Zealand Antarctic scientists are drawing a radical new picture of what created Antarctica.

It seems that a vast volcanic upwelling from the earth's mantle - a Plume - may have provided the force that broke the Gondwana super-continent apart and created the conditions that made it cold . But the continuing forces of geology may be responsible for the frightening possibility that it may not always stay that way.

[edit] The Ice Melts

"Calamity" - "Catastrophe" - "Collapse": Antarctica is the great unknown in the world's climate and its obscurity means that it has always been played as the wild card in global change. But it was Antarctica, protected by global treaty and kept pristine by environmental protocol, that actually gave the first solid evidence of the impact refrigerators and aerosols were having on the atmosphere. And it is Antarctica, the last great wilderness, hard to get to, harder to work in, that is now seen in almost biblical terms as the source of the next Great Flood.

The Western Antarctic Ice Sheet is the last Marine Ice Sheet on earth, and how it responds to warming past and present will determine the fate of great tranches of coast from Miami to Essex.

"Complete collapse of the Ice Sheet would raise sea levels by six meters" .

Yet in spite of the threat contained in this great reservoir of water no one knows quite what keeps it in check, how the ice sheet maintains its cycle of growth through snowfall and decline through the calving of icebergs at the continent's edge.

"The Ice Melts" is a detective story, as scientists scattered on the Ice Sheet try in a myriad of ways to understand the mechanisms that control it. At Siple Dome a large deep field camp, one group of American researchers are drilling for the climate core that will show if the Ice Sheet collapsed during the last interglacial.

Others investigate Ice Streams, mysterious glacial phenomena that control the flow of ice off the Sheet. Deep field near the Ellsworth Mountains British glaciologist, David Vaughan investigates the same thing to provide a comparison with the American work.

And as they drill and dig and core down in Antarctica, in down town Chicago, Doug MacAyeal, prophet of the coast line's future, sits at his desk and processes. For all this field data, this expensive, exhaustive and detailed glaciology, only achieves its meaning when it becomes part of a computer model.

The physics of the Ice Sheet - the sticky spots, lubrication, shear zones - are all being linked together to show what controls the movement of ice. And when the future is revealed by the computer it shows the stark possibility that the growth of the ice sheet creates the seeds of its own destruction.