(1) Antartic

ANTARCTICA: ULTIMATE JOURNEYS

UNEP - Antarctic Region

Antartic1

Tracing the Antarctic

The Antarctic has been defined and delineated with reference to latitude, climatic characteristics, ecological qualities, political and legal boundaries, as well as through appeals to its sublime wilderness and endangerment. There is some congruence between these spatial definitions but also important gaps. Some definitions are more tightly defined while others emphasize how the Antarctic might be thought of in more elastic, even fuzzy, terms.

Defining the sub-Antarctic

This refers in the main to island groups that lie close and sometimes north of the Antarctic Convergence – where the colder waters of the Southern Ocean meet the warmer waters of the Atlantic, Pacific, and Indian Oceans. These groups include Bouvet Island, the Kerguelen Islands, and the South Sandwich Islands. Unlike the Antarctic continent, countries such as Britain, France, Australia, New Zealand, and South Africa exercise sovereignty over these islands. Thus, they are in the main subject to undisputed territorial seas, exclusive economic zones, and continental shelf rights.

However, the ownership of some sub-Antarctic islands, such as South Georgia and South Sandwich, are disputed, in this case involving a long-standing disagreement between Britain and Argentina. In April 1982, the two countries were drawn into conflict over South Georgia and, further to the north, the Falkland Islands/Islas Malvinas. There are other islands, which are not considered sub-Antarctic sensu stricto, for example Southern Oceanic islands such as Gough and Auckland.

The Antarctic as an area, according to geographical convention at least, refers to everything below the Antarctic Circle, including ice shelves and water. The Antarctic Circle is distinguished from Antarctica, which refers to the landmass that is the southern polar continent. While the two terms are often used interchangeably, this is a fundamental distinction, as the area south of the Antarctic Circle (defined as 66°S of the Equator) experiences at least one day of continuous daylight every year (the December solstice), and a corresponding period of continuous night-time at least once per year (the June solstice). When it comes to the governance of the Antarctic, the Antarctic Convergenceern Ireland has also been used to manage activities such as fishing. Geographical latitude is only one possible register of the Antarctic. For the Swedish geologist Otto Nordenskjold, writing in 1928, the polar regions were defined by their coldness. Characterized as desert-like, with annual precipitation of only 200 millimeters along the coast and less in the interior, only specially adapted plant and animal life was thought to be able to endure. As Nordenskjold concluded, ‘Nowhere on earth is nature so completely and directly characterized by the daily regular weather – by what we might call the normal climate – as in the polar lands.’ Temperatures in the interior of the continent can be as low as -50 °C and, at their very worst, -89 °C, recorded at the Soviet/Russian Antarctic research station on the polar plateau called Vostok.

1. The Antarctic Convergence represents an important climatic boundary between air and water masses, and is also an approximate boundary for the Southern Ocean, surrounding the Antarctic continent. The water around the land mass is cold and with a slightly lower salinity than north of the convergence zone. The area is also rich in nutrients, providing a key support for the ecosystems in the Southern Ocean.

The Antarctic Convergence (sometimes termed the ‘Antarctic polar front’ or the ‘polar frontal zone’), where the cold body of water that is the Southern Ocean meets the warmer waters of the Indian, Pacific, and Atlantic Oceans, provides another definition of the Antarctic. Rather than a latitudinal delineation, we have here an oceanographic/climatic frontier that acts as a zone of transition emphasizing movement and connection. The convergence itself varies from year to year, depending on sea temperature and climatic trends. So these are flows that make, remake, and unmake a zone of some 30–50 kilometers in width, encircling the polar continent, and stretching north of South Georgia and Bouvet Island. It roughly coincides with the mean February isotherm (10°C) and lies around 58°S, considerably north of the Antarctic Circle. Air and sea surface temperatures change markedly once one crosses the Antarctic Convergence. In resource management terms, the Antarctic Convergence is significant because of the wealth of marine life, especially plankton and shrimp-like krill – the food of choice of birds, fish, and whales – that is found there. As such, it also means that fishing stocks and sea birds tend to be concentrated around the Antarctic Convergence, leading to greater interest in managing these areas of the Southern Ocean.

Unlike the zonal qualities of the Antarctic Convergence, the Southern Ocean is often defined as being south of 60° S latitude and thus encircling the continent. There is a disagreement, however. Does the Southern Ocean possess a more northerly boundary? While Captain James Cook used the term to describe the vast seas of 50°S, the International Hydrographic Organization cautiously established the boundary at 60°S in 2000. For Australians and New Zealanders, however, the water off the cities of Adelaide and Invercargill are the start of the Southern Ocean, thus consolidating their sense of these cities as ‘Antarctic gateways’.

The usage of the 60°S latitude for its tentative definition of the Southern Ocean coincides with the most important political definition of the Antarctic. Article VI of the 1959 Antarctic Treaty notes: Argentina, Australia, Chile, France, New Zealand and Norway.

The provisions of the present Treaty shall apply to the area south of 60° South Latitude, including all ice shelves, but nothing in the present Treaty shall prejudice or in any way affect the rights, or the exercise of the rights, of any State under international law with regard to the high seas within that area. This area of application entered into force in June 1961.

These lines and zones are just one way of tracing the Antarctic. In a more imaginative sense, we might acknowledge appeals to the sublime and wilderness. For 19th- and 20th-century explorers and scientists, the Antarctic was as much traced via the sublime as it was tentatively mapped and charted.

As a literary expression, this notion refers to the capacity of things in nature to overwhelm the human mind by their sheer grandeur and immense possibility. A place or landscape might, as a consequence, inspire awe or provoke terror. So the sublime refers to something beyond the calculable and measurable, and more to a state of mind. The Antarctic in this particular sense is a true frontier of the human and a testing ground of men in particular. Apsley Cherry-Gerrard’s memoir of Scott’s last expedition, The Worst Journey in the World (1922), memorably referred to the Antarctic as a place of privation and suffering. As he noted caustically, ‘Polar exploration is at once the cleanest and most isolated way of having a bad time which has been devised.’ But it could also be compelling, as Cherry-Gerrard noted, ‘And I tell you, if you have the desire for knowledge and the power to give it physical expression, go out and explore.’

2. The Antarctic Treaty’s Zone of Application

The notion that the Antarctic landmass should be defined by its wilderness qualities is explicitly noted in Article 3 of the 1991 Protocol on Environmental Protection, which demands that Antarctic Treaty Consultative Parties (ATCP) commit themselves to the ‘protection of the Antarctic environment … and the intrinsic value of Antarctica, including its wilderness and aesthetic values’. As well as for its own sake, Antarctica’s wilderness values matter when considered as part of an ongoing global debate about the fate of the planet. Recent television programmes (e.g. the BBC’s Frozen Planet), films (e.g. The March of the Penguins), music (e.g. Peter Maxwell Davies’s Antarctic Symphony), art (e.g. Anne Noble’s British Petroleum Map), and novels (e.g. Kim Stanley Robinson’s Antarctica) suggest that the idea of the Antarctic landmass as wilderness provokes fascination, but also anxiety about what damage we might be doing as a human community to it. Are economic and ecological meltdown coproducing one another?

Thus, as we ponder some of the region’s diverse human and physical geographies, our regional scope will extend northwards of the Antarctic Circle to encompass the northern tip of the Antarctic Peninsula, and islands such as Campbell, Prince Edward Islands, South Orkneys, and South Georgia, as well as the Southern Ocean. When we consider the Antarctic more broadly, whether it be culturally, economically, politically, or environmentally, our terms of reference will need to be ever more flexible to acknowledge bi-polar, global, and even extra-terrestrial connections, including the Moon (for parallels with Earth).

Making and unmaking the Antarctic

A satellite composite image of the Antarctic, a rather recent representation of the region, reveals a continent composed of two parts – East and West Antarctica with the western section characterized by a serpentine tail pointing towards the southern tip of the South American continent. The Southern Ocean is far removed from other continents and accompanying centres of population. The continent itself encompasses some 14,000,000 square kilometers, some 6,000,000 square kilometers larger than the United States. The coastline encompasses nearly 18,000 kilometers and is composed of a mixture of ice shelves, ice walls, rock and ice streams. The Antarctic ice sheet covers about 98% of Antarctica, and is on average 1.6 kilometers thick and some 25 million cubic kilometers in volume. The continent contains 90% of the world’s ice and 70% of the world’s fresh water. If the ice sheet was to melt in its entirety, then sea water levels would, it is believed, rise by some 60 metres, with devastating consequences for lower-lying regions around the world.

But this satellite image, however striking, is misleading. The Antarctic is the world’s most unstable space, with extraordinary changes being recorded every year in terms of snow accumulation and sea ice extent. The satellite image literally freeze frames. Every September, in the late winter period, the size of the continent effectively doubles. A large area of the Southern Ocean extending more than 1,000 kilometres from the coastline is temporarily covered in sea ice. This capacity to alter has, over time, played havoc with attempts to map and chart the Antarctic. Countless explorers and mariners have discovered to their cost that existing maps are hopelessly inaccurate, and that there is a rich tradition of islands and coastlines being in the ‘wrong place’ or simply ‘disappearing’.

Geologically, the Antarctic has a long and complex history, its composition ranging from Precambrian crystalline rock to glacial deposits of a recent vintage. Some of the world’s oldest rock is found in the Antarctic, dating back some three billion years. Geological evidence suggests that the Antarctic has not always been characterized by the snow and cold; it was, for much of its history, a green continent. Sedimentary rocks, to be found in the Antarctic Peninsula region, reveal fossilized tropical ferns and pollen specimens, while coal deposits in the Trans-Antarctic Mountains suggests a climate favouring temperate vegetation. In the Cambrian era (590 to 505 million years ago), what we now term Antarctica was part of Gondwanaland, a super-continent composed of present-day South America, Africa, and Australia as well as parts of India, Madagascar, and New Zealand. It straddled the Equator, and layers of limestone, sandstone, and shale were deposited in tropical seas. The eastern portion of Antarctica reveals fossil evidence of marine plants such as tropical sponges. During the late Cambrian and Devonian periods (480 to 360 million years ago), the super-continent migrated towards the southern hemisphere, and some of Antarctica’s oldest fossil plants found in the Trans-Antarctic Mountains have been dated to about 360 million years ago. In other areas of the polar continent such as Victoria Land, the fossilized remains of marine life have been found.

As the super-continent experienced further cooling, so glacial deposits formed, and by about 280 million years ago, Gondwanaland was located around the current location of the polar continent. But the super-continent did not remain in a fixed position, and as it moved again slightly northwards, so new flora and fauna emerged including fern-like plants, later to contribute to the formation of coal deposits in the Trans-Antarctic Mern Ireland.

Some 90–85 million years ago, in the Cretaceous period, this rich and biologically diverse supercontinent began to disintegrate and transformed the southern latitudes. As Gondwanaland fragmented still further, the Atlantic, Indian, and Pacific Oceans were established, and Australia alongside Antarctica migrated southwards. Some 30–40 million years ago, Antarctica slipped even further south.

This drift helped to cause the separation between the South American Andes and the Antarctic Peninsula, and in the process this tectonic schism created an oceanic passage later to be named the Drake’s Passage. It is only through major scientific investment, and the development of new techniques involving geophysical and remote-sensing research, that we have a better idea of the underlying geology of the polar continent and Southern Ocean. The exact mechanisms of plate movement, however, remain opaque.

The Antarctic continent possesses a series of important geological and morphological characteristics. It is a continent surrounded by a ring of water – the Southern Ocean. Due to the circumpolar current, waters circulate around the continent in a predominantly clockwise direction. There is a series of mountainous ranges, including those found on the Peninsula region, which are connected geologically to the South American Andes. Centrally, the Trans-Antarctic Mountains weave through the centre of the continent from the Weddell Sea to the north to the Ross Sea in the south. Divided into two distinct parts by the Trans-Antarctic Mountains, the East and West portions of the continent were named for their relative positions to the Greenwich meridian.

The immense Antarctic ice sheet, created over millions of years, without melting, covers the polar continent. Due to pressure brought on by the sheer weight of 13 million square kilometers of extent, the ice flows from the continental interior towards the coastline. Large slabs break off, dramatically initiating icebergs to drift outwards towards the Southern Ocean. In 2002, the Larsen B Ice Shelf splintered and was widely judged to be indicative of a warming planet. In 2008, a huge chunk of the Wilkins Ice Shelf became detached, and 570 square kilometers of ice floated out to sea.

Unsurprisingly, there is much interest amongst the scientific community as to how the mass of this ice sheet has altered, and the overall ratio between accumulation and loss of ice. The changing state of the ice sheet and specific ice shelves such as the Larsen B is providing invaluable evidence of past climates, and a sobering warning of what further warming might do to other ice shelves. 3. Ice thickness map of the Antarctic West Antarctica is composed of the Antarctica Peninsula, Ellsworth Land, Marie Byrd Land, and the islands located within the Scotia Sea. Geologically, West Antarctica, especially the Antarctic Peninsula, is connected with a circum-Pacific chain of mountains. The Andes and the Antarctic Peninsula are, quite literally, connected to one another. The average elevation is 2,000 metres, and the chain is home to the continent’s highest mountain, Mount Vinson, at 4,897 metres.

N a great deal en Peninsula to withstanding these heights, a large part of West Antarctica is covered by the West Antarctic Ice Sheet (WAIS). This is a marine-based ice sheet because its base actually lies below the sea level, and its edges transform into floating ice shelves. The WAIS is believed to contain about 10% of the total volume of the Antarctic ice sheet, and some two million cubic kilometres of ice press down on the underlying bedrock. While the net result has been to depress the baseline, the ice can flow at different rates over the bedrock depending on local topographies. This subterranean variability is of interest to scientists because of concerns that the WAIS may not be stable. If the WAIS disintegrates, then global sea levels could rise some 3–4 metres. In 2006, the British Antarctic Survey (BAS) warned about the possible collapse of this ice sheet, and noted that there was a danger that a tipping point might be reached thereafter accelerating ice sheet degeneration. Evidence for this change comes from research into a number of glaciers within the WAIS, coupled with observations about ocean circulation patterns around Western Antarctica that have reported a rise in ice mass loss in the period between 1996 and 2006.

East Antarctica lies on the other side of the 3,500-kilometre-long Trans-Antarctic Mountains, closer to the Indian Ocean. Geologically, the eastern portion is a stable ancient shield of Precambrian rock, similar in nature to that found in South America, South Africa, India, and Australia. It is here that the oldest rocks in Antarctica have been found, some dated to 3,900 million years ago. East Antarctica is covered by the East Antarctic Ice Sheet (EAIS), and rests on a large landmass, unlike the marine based WAIS. It is a thicker and larger ice sheet, with a thickness of up to 4,800 metres. The South Pole is to be found on the EAIS, and beneath it lie spectacular sub-glacial lakes such as Vostok – about the size of Lake Ontario, stretching some 50 kilometres in length, and possibly created some two to three million years ago. East Antarctica is the largest and coolest portion of the polar continent, stretching from Queen Maud Land and encompassing the vast polar plateau including Wilkes Land and Victoria Land. The future stability of this part of the continent depends inter alia on ozone concentration coupled with weather patterns, including the polar vortex which helps to trap cold air near the South Pole.

The Antarctic coastline is immensely varied, rising steeply in places such as the mountainous Antarctic Peninsula and areas adjacent to the Ross Sea. Immense ice cliffs are to be found along much of the East Antarctic coastline. In other regions, floating ice shelves such as the Brunt Ice Shelf and the Ronne Ice Shelf represent the end point of glaciers flowing out towards the sea. Beyond the Antarctic coastline, the continental shelf falls sharply into tectonically active ocean basins, which lie anywhere between 3,000 to 6,000 metres depth. Volcanoes are to be found onshore and offshore, even if most are concentrated in western Antarctica.

Scientific curiosity remains piqued, as less than 1% of Antarctica’s rock is actually accessible for direct examination, and researching the deep geology of the Southern Ocean presents considerable challenges. There is still a great deal to discover

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