Introduction to Antarctica
– Etymology: The name ‘Antarctica’ originates from the word ‘antarctic,’ which means ‘opposite to the Arctic.’
– Geography: Antarctica is positioned around the South Pole and is largely south of the Antarctic Circle. It is surrounded by the Southern Ocean. Antarctica covers an area of over 14.2 million square kilometers, making it the fifth-largest continent. The coastline of Antarctica is almost 18,000 kilometers long, with different types of coastal formations. The majority of Antarctica is covered by the Antarctic ice sheet, which is about 1.9 kilometers thick.
Climate and Environment of Antarctica
– Climate: Antarctica is the coldest, driest, and windiest continent. It has the highest average elevation among all continents. The continent is mainly a polar desert, with limited precipitation. The coastal regions receive more precipitation than inland areas. Antarctica holds about 70% of the world’s freshwater reserves, which are mostly frozen in the ice.
– Wildlife: Native species in Antarctica include mites, nematodes, penguins, seals, and tardigrades. Vegetation, when present, is mostly in the form of lichen or moss. Antarctica is home to various species of penguins, such as the Emperor Penguin and Adélie Penguin. Seals, including Weddell seals and leopard seals, can be found along the coast. Tardigrades, also known as water bears, are microscopic animals that can survive extreme conditions in Antarctica.
Human Activity in Antarctica
– Governance: Antarctica is governed by about 30 countries under the Antarctic Treaty System. Military activity, mining, nuclear explosions, and nuclear waste disposal are prohibited in Antarctica.
– Activities: Tourism, fishing, and research are the main human activities in and around Antarctica. During the summer, around 5,000 people reside at research stations, which decreases to about 1,000 in the winter. Human activity in Antarctica has significant effects on the environment, including pollution, ozone depletion, and climate change.
Geologic History of Antarctica
– Paleozoic Era: Antarctica was part of the supercontinent Gondwana during the Neoproterozoic era to the Cretaceous. During the Paleozoic era, Antarctica became glaciated and the climate cooled.
– Mesozoic Era: Antarctica continued to warm and dry out during the Triassic period. The Jurassic period saw the formation of the Antarctic Peninsula and the presence of diverse flora.
– Gondwana Breakup: Africa separated from Antarctica in the Jurassic, followed by the Indian subcontinent in the early Cretaceous. Australia-New Guinea separated from Antarctica around 53 Ma, opening the Tasmanian Passage. The Drake Passage opened around 30 Ma, resulting in the creation of the Antarctic Circumpolar Current and the spread of ice. Present day: The geology of Antarctica is being revealed through remote sensing and other techniques. West Antarctica resembles the South American Andes, while the Antarctic Peninsula was formed by geologic uplift. East Antarctica is geologically varied, with a Precambrian Shield and formations like the Transantarctic Mountains.
Climate Change and Impact on Antarctica
– Climate Change: Average temperature increase of 0.05°C/decade since 1957 across Antarctica. West Antarctica warmed by over 0.1°C/decade from the 1950s to the 2000s. Antarctic Peninsula warmed by 3°C (5.4°F) since the mid-20th century. East Antarctica had been experiencing cooling until the 2000s. Southern Ocean has absorbed more heat than any other ocean.
– Ozone Depletion: Ozone hole discovered over Antarctica in 1985. Depletion caused by chlorofluorocarbons and halons in the atmosphere. Montreal Protocol restricts emissions of ozone-depleting substances. Ozone levels expected to return to 1980s values by the 2060s.
– Biodiversity: Most species in Antarctica are descendants of species that lived there millions of years ago. Species survived glacial cycles in isolated warmer areas. Limited terrestrial invertebrates on sub-Antarctic islands. Antarctic krill is the keystone species of the Southern Ocean ecosystem. Marine animals rely on phytoplankton for survival.
– Impact on Sea Levels: Net ice loss from Antarctica expected to add about 11cm (5in) to global sea level rise by 2100. West Antarctica may contribute tens of centimeters more if triggered before 2100. West Antarctic ice sheet could eventually all melt unless temperatures are reduced. Isostatic rebound may add around 1m (3ft 3in) to global sea levels over 1,000 years. East Antarctic ice sheet may cause 0.5m (1ft 8in) – 0.9m (2ft 11in) of sea level rise.
