The Arctic is the region around the Earth’s north pole. It includes the ice-covered Arctic Ocean, parts of Canada, the USA, Greenland, Iceland, Finland, Norway, Sweden and Russia. The area is commonly defined as lying north of the line of latitude known as the Arctic Circle (running at 66° 34’ N.) or inside the 10°C July isotherm.
The climate is harsh, particularly during winter (October–March) when the Arctic receives little sunlight; the average monthly temperature in December, January and February is around −10 to −15°C. Continental areas, including Northern Canada and Alaska, can experience lows of −60°C in winter. In summer, the interior of Greenland remains subzero, while more southerly regions such as the Siberian tundra, can rise to 30°C. Coastal areas, including Iceland and Northern Scandinavia, have a milder, maritime climate with an average yearly temperature of 10°C. The Arctic is rarely as cold as the Antarctic since there is water, not land, underneath the Arctic ice. The water is warmer than the air above it, causing heat to rise and moderate the cold.
The polar bear is the region’s apex predator. Other native species include varieties of caribou, lemming, wolf, hare and fox; around 200 bird species migrate to tundra areas in summer. Until recently, vegetation was limited to Arctic tundra, a biome consisting of around 1,700 species of low-lying shrubs, grasses, sedges, lichens and mosses. However, this tundra is slowly being replaced with flora typical of more southern locations, such as trees and evergreen shrubs. In 2013, a comprehensive study of these changes, the Arctic Biodiversity Assessment (W ), concluded that climate change and the effects of collective industrial development were degrading arctic biodiversity.
ARCTIC SEA ROUTES
In 1906 Norwegian explorer Roald Amundsen first successfully navigated the Northwest passage, but the shallow waterways he encountered ensured that the route held little commercial potential until recently. Similarly, the Northern Sea route (formerly the Northeast passage) linking the Atlantic and Pacific oceans around Russia's Arctic coast, was first navigated by Finnish-Swedish explorer Adolf Erik Nordenskjold in 1878–9, but thereafter only icebreakers and Russian submarines regularly traversed it.
In summer 2007, the Northwest passage was declared open for the first time since records began in late 1978; the first commercial ship travelled through it in September 2008. In August 2008 the Northwest passage and the Northern Sea route were open simultaneously for the first time, making the Arctic circumnavigable. Two German cargo vessels became the first to navigate the Northern Sea route in September 2009 and in August 2012 The World became the largest passenger ship to navigate the Northwest Passage, following Amundsen's route.
The extent of ice in the Arctic has become a key measure of global climate change. The rate at which the ice melts grows exponentially: whereas the white ice reflects sunlight back into space, the darker seas absorb its heat, and the rising sea temperature melts the surrounding ice. The area of the sea ice reaches its greatest extent in March and retreats to its lowest point in September. The minimum ice extent in September 2016 was recorded as 4.14 million km2 (1.60 million miles2); 750,000 km2 (290,000 miles2) above the record minimum extent, which occurred in September 2012, and 2.56 million km2 (999,000 miles2) below the 1979 to 2000 average minimum. Since 2010, estimates of sea ice thickness and volume have been obtained via the European Space Agency's CryoSat satellite. In October 2015 CryoSat measured approximately 6,200km3 (1,487 miles3) of sea ice at the end of the summer melt, only slightly reduced from 7,500km3 (1,799 miles3) in October 2013. It was the fourth lowest volume of sea ice yet recorded; it is estimated that in the early 1980s, October ice volume was around 20,000km3 (4,800 miles3).
The Arctic's receding ice presents opportunities for national governments to lay claim to a wealth of hydrocarbon and mineral deposits. In 2008 the US Geological Survey estimated that 20 per cent of the world's undiscovered oil and gas reserves – as much as 90 billion barrels of oil, 44 billion barrels of natural gas liquids and 1,670 trillion cubic feet of natural gas – are located within the Arctic Circle. In December 2016 the USA and Canada introduced bans on offshore drilling covering large portions of the Arctic. Under the 1982 UN Convention on the Law of the Sea, no state owns the pole or the ocean surrounding it: the five countries that border the Arctic Ocean – Canada, Denmark, Norway, Russia and the USA (a non-signatory) – are limited to an economic zone of 200 nautical miles from their coastline, unless able to prove that their continental shelf extends beyond that limit. Under the convention the countries have ten years from their date of ratification to assert a claim that their continental shelf extends into arctic territory. In August 2007, Russia planted a flag in the seabed below the pole, on the Lomonosov Ridge which spans much of the Arctic, and which Russia claims is an extension of the Eurasian continent and therefore part of its territory. However, Canadian geologists assert that Lomonosov is an extension of the North American continent, and therefore falls under their jurisdiction. In December 2014 Denmark followed Canada, Norway and Russia in submitting a claim under UNCLOS, arguing that the Lomonosov Ridge is an extension of Greenland's continental shelf. Russia resubmitted its bid in August 2015, laying claim to 1.2 million km2 of the shelf.
The Antarctic is generally defined as the area lying within the Antarctic Convergence, the zone where cold northward-flowing Antarctic sea water sinks below warmer southward-flowing water. This zone fluctuates unevenly between the latitudes of 48° S. and 61° S., typically extending further north in the Atlantic Ocean than in the Pacific. The continent itself lies almost entirely within the Antarctic Circle; it has an area of around 14 million km2, 98 per cent of which is permanently ice-covered. In 2013 the international project Bedmap2 found that the average thickness of the grounded ice is 2,126m, but can reach 4,776m in places; it amounts to some 26.5 million km3, and represents around 90 per cent of the world’s fresh water and 91 per cent of the world's glacier ice. Much of the sea freezes in winter, forming fast ice which breaks free of the coast in summer and drifts north as pack ice.
CLIMATE AND TERRAIN
Antarctica is the highest, coldest and driest continent on Earth, with average coastal temperatures ranging from just above freezing in the summer (December–February) to −30°C in winter. Conditions on the interior plateau are more severe, with katabatic (gravity-driven) winds and frequent cyclonic storms pushing average winter temperatures down to −65°C. The Vostok research station holds the record for the lowest surface temperature recorded on Earth at −89.2°C in 1983. Elevation extremes range from 4,897m (Vinson Massif) at the highest point to more than −2,500m (Bentley Subglacial Trench) at the lowest. The Transantarctic mountains bisect the continent north–south, dividing the west Antarctic ice-sheet – an ice-filled marine basin – from the significantly larger and more elevated east sheet. Precipitation levels range from less than 50mm a year inland to around 400mm in some coastal areas. With average precipitation of just 140mm a year, Antarctica is considered a desert.
While the recent decline in levels of ice in the Arctic has been clear and visible, concurrent changes in the Antarctic have been more complex. Despite reports of a recent thickening of the interior of the east ice-sheet due to increased snowfall, studies of data produced by the European Space Agency's Cryosat satellite indicate that the Antarctic ice-sheet as a whole has declined by more than 500 km3 (30 miles3) a year since 2010. However, the continent appeared to be gaining temporary sea ice in winter – which extended to a record 20.11 million km2 (7.76 million miles2) in September 2014 – probably due to increased meltwater from the land ice which re-freezes more easily than the ocean water below. This growth slowed in 2015 and on 13 February 2017 the US National Snow and Ice Data Center recorded that sea ice extent contracted to a record low of 2.28 million km2 (883,015 miles2).
The British Antarctic Survey has found that the west coast of the Antarctic Peninsula has become one of the fastest-warming areas on the planet, with annual mean temperatures rising by around 3°C over the past 50 years. In March 2015 a record high of 17.5°C was recorded at the Esperanza research station on the western peninsula. In 2009, a group of British geophysicists found that the retreat of the Pine Island Glacier in the Western Antarctic had quadrupled between 1995 and 2006. However, the temperatures recorded by the Amundsen-Scott station at the South Pole actually show a recent cooling, as do some studies of east Antarctica. It has been determined that these falling temperatures have been caused by the thinning of Antarctica's ozone layer that has in turn cooled the stratosphere above the continent. The historical use of chlorofluorocarbons (CFCs) by humans has contributed to the destruction of Antarctica's ozone layer, as the clouds that form in the winter polar vortex – an area of very cold air above the continent – react with these CFCs to release chlorine which destroys ozone. Antarctic ozone levels are expected to recover by 2050 and this could result in warmer temperatures in the region.
HISTORY AND DISCOVERY
The idea of Antarctica is much older than proof of the continent’s existence. The notion of Terra Australis, a vast southern continent which counterbalanced the northern lands of Europe, Asia and North Africa, originated with Aristotle, and was depicted on a world map as early as 1531. The supposed size of this land was gradually amended over the course of 16th-century exploration and further corrected after James Cook's circumnavigation of the globe in 1774. His journey from New Zealand to the Cape of Good Hope (via Tierra del Fuego), travelling at a high southern latitude (between 53° and 60°), confirmed that any land mass must be confined to the polar region.
The date of the first sighting of Antarctica is unclear. In 1820 three separate expeditions, from the UK, the USA and Russia, each claimed to have seen the continent within days of each other, and the argument has never been settled. The golden age of Antarctic exploration was prompted by the discovery of the magnetic North Pole in 1831, but it was not until the beginning of the 20th century that real progress was made. James Clark Ross was the first to identify the approximate location of the South Pole, but was unable to reach it. British explorers Robert Scott in 1901–4 and Ernest Shackleton in 1907–9 got closer, but it was not until Norwegian adventurer Roald Amundsen pioneered a new route, through the Axel Heiberg Glacier, that the pole was reached in December 1911. Scott’s second attempt was also successful, but he arrived a month later and perished with his team on the return journey.
FLORA AND FAUNA
The only land animals to survive on the Antarctic continent are tiny invertebrates, including microscopic mites, lice, ticks, nematodes, rotifers and tardigrades. The largest land animal is the Belgica antarctica, a flightless midge just 2–6mm in size. The snow petrel, one of only three birds that breed exclusively in Antarctica, has been spotted at the South Pole. Large numbers of seals, penguins and other seabirds go ashore to breed in the summer; the emperor penguin is the only species that breeds ashore throughout the winter. Four species of albatross breed in South Georgia during the summer, but their numbers are in serious decline owing to the effects of longline fishing in the Southern Ocean region. Recent climate change has also affected the continent’s wildlife, with the number of Adélie penguins falling significantly, as open-water species such as the chinstrap and gentoo penguins invade its Antarctic Peninsula habitat to take advantage of the warming temperatures.
By contrast, the Antarctic seas abound with life; recent expeditions identified over 700 previously unknown species. Krill, which congregates in large schools, is crucial to the ecosystem and provides a diet for migratory whales (including killer, humpback and blue whales), a number of species of seal, penguin, albatross and other, smaller birds. Each of these species is threatened by a substantial fall in recorded levels of krill since the 1970s, thought to be caused by warmer sea water and, paradoxically, the decimation of the blue whale through hunting in the first half of the 20th century: although whales eat krill, the iron in whale excrement is essential to the algae on which the krill feed. In 2010 a group of research bodies completed the Census of Antarctic Marine Life, an inventory of over 16,000 marine species compiled from 19 expeditions; scientists estimate that 39–58 per cent of the Antarctic's marine species are yet to be described.
With almost all of the Antarctic continent permanently covered in ice, only a small number of flowering plants, ferns and club mosses survive. Most of these are found on the sub-Antarctic islands, while only two species (a grass and a pearlwort) extend south of 60° S. Antarctic vegetation is dominated by lichens and mosses, with a few liverworts, algae and fungi surviving in the cracks and pore spaces of sandstone and granite rocks.
The Antarctic Treaty was signed on 1 December 1959 when 12 states (Argentina, Australia, Belgium, Chile, France, Japan, New Zealand, Norway, South Africa, the Soviet Union, the UK and the USA) pledged to promote scientific and technical cooperation unhampered by politics. The signatories agreed to establish free use of the Antarctic continent for peaceful scientific purposes; freeze all territorial claims and disputes in the Antarctic; ban all military activities in the area; and prohibit nuclear explosions and the disposal of radioactive waste. The Antarctic Treaty was defined as covering areas south of latitude 60° S., excluding the high seas but including the ice shelves, and came into force in 1961. The treaty provides that any member of the UN can accede to it; it has since been signed by a further 41 states. In 1998 an extension to the treaty came into effect, placing a 50-year ban on mining, oil exploration and mineral extraction in Antarctica, and stipulating that all tourists, explorers and expeditions now require permission to enter the Antarctic from a relevant national authority. However, in recent years the region's coastal states have asserted often conflicting claims to oil- and gas-rich territory on the Antarctic seabed. Under the terms of the UN Convention on the Law of the Sea, each nation's sovereignty over its continental shelf extends up to 350 nautical miles beyond its territorial coasts; the UN Commission on the Limits of the Continental Shelf is examining evidence submitted in support of these claims.
As at March 2017 there were 20 nations with permanently manned research stations in Antarctica:
Brazil, Germany, Italy (*shared with France), Japan, New Zealand, Norway, Poland, South Africa, Ukraine and Uruguay each have a single station.
POPULATION AND TOURISM
Antarctica has no indigenous inhabitants, although the continent maintains a population of tourists, scientists and research workers which peaks in the summer months at over 4,400.
Antarctic tourism is a growth industry. The first Lonely Planet guide to Antarctica was published in 1996, and ship-borne cruises typically depart from Argentina, Chile and the Falkland Islands. The continent has also become a popular venue for extreme sports enthusiasts: it is now possible to sky-dive, ski, ride a motorbike and fly a helicopter across the continent, and the Vinson Massif and other peaks have become desirable destinations for mountaineers. The huts built by Scott and Shackleton are also popular attractions. In 1991 the International Association of Antarctica Tour Operators (IAATO) was founded with the objective of providing a self-regulating code of conduct for all operators to follow, but membership is voluntary, and fears remain regarding tourism-related environmental damage. IAATO recorded 6,704 tourists in the 1992–3 summer season, rising to more than 46,000 in 2007–8 and dipping to 38,478 in 2015–16.
THE BRITISH ANTARCTIC SURVEY
The British Antarctic Survey (BAS) is part of the Natural Environment Research Council and carries out the majority of Britain’s scientific research in Antarctica. Over 500 staff are employed by BAS and the organisation supports five research stations, four of which are staffed throughout the winter months (two in South Georgia and two in Antarctica). An unmanned submersible, named Boaty McBoatface in a public competition, embarked on its first Antarctic research mission in March 2017 aboard the BAS ship RRS James Clark Ross. See the BAS website (W ) for further information.