Clean Sheets

Article excerpt

Research in the Antarctic can reveal our past and help predict our future. Martin Varley unlocks the secrets of this cold land of science

OUTSIDE THE TENT where Captain Scott and his companions lay dying on their ill-fated expedition to the South Pole stood a sledge loaded with rocks that Edward Wilson, the Chief of the Scientific Staff, had dragged for 300 hungry, frozen miles across the Antarctic Desert. Had the men survived, Wilson's cargo may have had as profound and far-reaching an effect on science as their failed attempt to be first to the pole had on discovery and exploration. The rocks, on later analysis, were found to contain fossils of southern beech trees, which today still grow in South America, New Zealand and Australia. Three years later Alfred Wegener would be the first to put forward the controversial idea that continents could have drifted to their present position, and it was to be another 50 years until the idea of plate tectonics was finally accepted. Wilson died not realising that he had collected evidence which would have proved Antarctica was once part of the great semi-tropical southern continent now known as `Gondwanaland'.

Antarctica is unique. It is the highest, driest, windiest and most remote continent on Earth. At the start of the last century, astronomers could say more about the moon than scientists knew about Antarctica. As well as being vastly different from the rest of the planet, the South Pole region is also distinct from its northern counterpart. The Arctic is a frozen ocean surrounded by a rim of inhabited continents, whereas the Antarctic is an icy continent cut off from the rest of the world by a hostile sea. Above all, the Antarctic is characterised by an extraterrestrial cold. Average monthly temperatures at the South Pole vary between -60 [degrees] C and -30 [degrees] C, making it as frigid as the surface of Mars.

Since the Antarctic Treaty came into force in 1961, Antarctica has been a land for scientific research, with 26 nations currently carrying out research there. But for the first two decades following the signing of the Antarctic Treaty it was questionable whether science on this alien continent, far removed from the rest of the world, had any meaning outside of its frozen boundaries. Then in 1985 something happened which brought Antarctic science in from the cold and on to the world stage. British Antarctic Survey scientists announced that Antarctic ozone levels were falling in each successive spring to unprecedented levels. Meticulous research subsequently showed that chemical reactions catalysed by the surfaces of polar stratospheric clouds were responsible for the destruction. The source of these ozone-destroying chemicals was inert chlorofluorocarbons and halons, used in industrial applications and refrigeration throughout the northern hemisphere.

However, one of the most startling realisations about the discovery of the hole in the ozone layer, was not the hole itself, but that for the first time localised human activity was implicated in global environmental change. Although Antarctica is geographically detached from the rest of the world, it became clear that it was related physically, through atmospheric and oceanic circulations. As the scientists' understanding of the global influence of human activity has grown, Antarctica has become an early warning system for the rest of the world, not least for the most notorious of environmental malaises -- global warming.

Antarctica locks up 30 million cubic kilometres of ice; 90 per cent of the world's total, coating a continent 58 times larger than the UK to an average depth of 2,000 metres. It contains about 90 per cent of the world's freshwater, which if it melted would raise sea levels by 65 metres. The ice keeps the South Pole cool and the South Pole cools the Earth by restricting the exchange of heat between the atmosphere and the oceans.

In April 1998, a 120 square-kilometre chunk of the Larsen B ice shelf, on the eastern side of the Antarctic Peninsula, collapsed into the sea. …