Antarctica is a vast, remote natural laboratory. Each year, several thousand scientists brave the coldest, driest and windiest conditions on Earth hoping to glean new facts about the workings of our planet. Armed with wind-speed recorders, global positioning system receivers and plankton-catching nets, they regularly venture forth from the continent's 35 or so research stations to monitor and muse over the surrounding snow, air, ocean, fauna and flora. As a result of the work of these meteorologists, geographers and biologists, we now know Antarctica was once covered in forests, that global warming is prompting new plants to colonise its soil and that a gaping hole exists in the ozone layer above the South Pole.
Unlike the other continents, which have been inhabited for thousands of years, Antarctica has no indigenous people. The existence of the continent was established only around two centuries ago, although myths of an unknown land deep in the southern hemisphere began circulating much earlier.
Ancient Greek philosophers knew the Earth was spherical and thought there must be a landmass in the far south to "balance lands" atop the northern hemisphere.
They named the northerly region "Arkitos", meaning bear, after the constellation beneath which it lay. "Ant-Arkitos" - opposite the bear - became the name for this supposed southern land. Others later called it Terra Australis Incognita, "Unknown Southern Land".
The voyages of Marco Polo, Vasco da Gama and Fernand de Magellan between the 13th and 16th centuries revealed much about the world's geography, but stopped short of uncovering the mysteries of the Southern Ocean. However, 17th-century tales of sailors being pushed towards icy lands by storms off Cape Horn prompted a flurry of expeditions with the aim of penetrating southern latitudes. Not all seafarers were honest in reporting what they found. When French captain Yves-Joseph de Kerguelen-Tremarec returned from an expedition in 1772, he claimed to have discovered a rich and fertile land. Only when Captain James Cook circumnavigated Antarctica during the following three years were these claims disproved.
Although Cook didn't spy land, he surmised its existence from the presence of boulders in icebergs, and suggested it would be uninhabitable and lifeless. "I make bold to declare that the world will derive no benefit from it," he said. His dismissive comments did little to deter entrepreneurs who realised there was wealth to be gained from hunting whales and seals in the Southern Ocean. Reports by various individuals that they had spotted the continent with their own eyes prompted a race to be first to set foot on it.
French navy officer Sebastien Cesar Dumont d'Urville claimed this victory but a Norwegian team led by Henryk Bull made the first confirmed landing in 1895. This helped usher in the so-called heroic age of exploration. Between 1895 and 1915, all eyes turned South as Scott and Amundsen raced to reach the Pole. Shackleton sailed treacherous seas and crossed uncharted mountains to rescue his men when their boat, The Endurance, was crushed by ice. Sailors from Japan and other countries made their first visits to Antarctica in this period.
Thanks to these pioneering ventures, along with recent advances in science and technology, we now have a clear understanding of Antarctica's geography. A series of images taken over time reveals the continent's fluctuating area. The land itself takes up about 14 million km2; there is an additional 2.5 million km2 of sea ice which increases to 19 million km2 in winter. The continental ice sheet, 5km thick in places, makes Antarctica the world's highest continent, with an average altitude of 2,300m above sea level. (In comparison, the UK's highest peak, Ben Nevis, is only 1,343m high.) The ice is so thick because it has built up over millions of years. On average, only 50mm to 900mm of snow are added every year, although in the Dry Valleys region it has not rained or snowed for thousands of years.
Geologists believe these valleys formed during the Cenozoic era, which began 135 million years ago. The Transantarctic Mountains were squeezed upwards, and water run-offs from the glaciers were cut off by rocks. These Valleys represent the only 2 per cent of Antarctica that is not covered by the ice and snow that blanket the rest of the continent.
Huge glaciers flow from the interior towards the coast, where giant icebergs are calved (the word for ice breaking off glaciers), some the size of small countries. These often pose hazards to shipping, and sometimes to wildlife. In December, scientists reported that the largest iceberg in the world, B-15A, with an area of 3,000km2, had cut off 5,000 Adelie penguins from their food supplies.
The extreme conditions on land mean Antarctica's terrestrial biodiversity is very low. Most of the vegetation comprises fungi, mosses, liverworts and lichens, with flowering plants limited to just two, hairgrass and pearlwort. The only purely land-based animals are minute creatures such as mites and nematodes. Though penguins and seals rear their young on Antarctic shores, they have to return to the sea to feed.
Few land creatures can tolerate life on the continent because what little land is ice-free has only been exposed since the end of the last Ice Age, a mere 11,000 years ago. Not enough time has passed for animals and plants to adapt to the extreme conditions. It is not unusual for coastal areas to experience winds of 80km per hour, and temperatures regularly drop to - 20C.
The coldest temperature ever recorded, - 89.5C, was in Antarctica at Vostok.
But the biodiversity of the surrounding ocean is greater than you might expect. There is a great variety of seabirds, including several species of albatross, gulls, shearwaters and the blue-eyed shag. Eight species of whale, around 200 species of fish and vast quantities of zooplankton are found there. "The Southern Ocean contains 8 to 9 per cent of the world's water by volume and Antarctica has around 2 to 3 per cent of the world's coastline," explains Professor Lloyd Peck, head of the British Antarctic Survey's Life at the Edge programme.
"Yet 17 per cent of sea spider species live around Antarctica, and 9 to 10 per cent of sand hopper species live there. Things have been able to adapt because the Southern Ocean around Antarctica has existed for 30 million years and it's been cold for around 10 to 15 million years. Unlike the land, the sea is large, old and constant."
The Americans are currently building a compacted ice road which is 6m wide and 1,934km long. The road, due to be finished next year, will run from the coast to the US base at the South Pole. It will be used two or three times a year to transport supplies which are currently flown in by plane. The long-term future of this road is uncertain as the ice is unstable and they have already had repair cracks.
The UK is one of 25 countries with permanent research stations in Antarctica and the outlying South Shetland Islands. The others include the US, Russia, South Africa, Germany, Japan, Australia, China, France and Argentina. These are dotted around the coastline, with the exception of Russia's Vostok base, deep in East Antarctica, and the USAmundsen-Scott base at the South Pole.
Rather than adopt a standard time, each base tends to operate on its own time zone. UK bases adopt a local time but Chinese bases use their own country's time zone. So the time in Antarctica depends on whose base you're standing in. Current research projects range from studies of a vast lake lying beneath the ice, to the impact on scientists of living in darkness for six months.
Scientific work is given priority in Antarctica because of an agreement signed 45 years ago. At the time, several nations had set up research stations on the continent and plans were under way for a multinational research programme called the International Geophysical Year. However, the participating countries did not all agree with each other's claims for territory and the resulting tension threatened to undermine future scientific work. Rather than let this happen, the 12 nations involved agreed that peaceful scientific co-operation on the continent should continue indefinitely.
The Antarctic Treaty signed on December 1, 1959, laid down rules for the use of all land below 60x south. These stipulate that Antarctica should be used purely for peaceful purposes and guarantee freedom for academics provided they make their research available to all. It has been used as the world's natural laboratory ever since, and remains a beacon for peace and scientific endeavour.