Biodiversity among terrestrial flora and fauna is low on the islands: studies have theorized that the harsh climate was a major contributor towards species richness, but multiple correlations have been found with area, temperature, remoteness of islands, and food chain stability. For example, herbivorous insects are poor in number due to low plant richness, and likewise, indigenous bird numbers are related to insects, which are a major food source.[12]
The Antarctic hosts the world's largestprotected area comprising 1.07 million km2, the South Georgia and the South Sandwich Islands Marine Protection Area created in 2012.[13] The latter exceeds the surface area of another vast protected territory, theGreenland National Park's 972,000 km2 (375,000 sq mi).[14] (While theRoss Sea Marine Protection Area established in 2016 is still larger at 1.55 million km2, its protection is set to expire in 35 years.[15][16]) To protect the area, all Antarctic ships over 500 tonnes are subject to mandatory regulations under thePolar Code, adopted by theInternational Maritime Organization (in force since 1 January 2017).[17][18]
Antarctic surface ice layer temperature trends between 1981 and 2007, based on thermalinfrared observations made by a series ofNOAA satellite sensors.
Despite its isolation,Antarctica has experiencedwarming and ice loss in recent decades, driven bygreenhouse gas emissions.[19][20]West Antarctica warmed by over 0.1 °C per decade from the 1950s to the 2000s, and the exposedAntarctic Peninsula has warmed by 3 °C (5.4 °F) since the mid-20th century.[21] The colder, stablerEast Antarctica did not show any warming until the 2000s.[22][23] Around Antarctica, theSouthern Ocean has absorbed moreoceanic heat than any other ocean,[24] and has seen strong warming at depths below 2,000 m (6,600 ft).[25]: 1230 Around the West Antarctic, the ocean has warmed by 1 °C (1.8 °F) since 1955.[21]
The warming of the Southern Ocean around Antarctica has caused the weakening or collapse ofice shelves, which float just offshore ofglaciers and stabilize them. Many coastal glaciers have been losing mass and retreating, causing net ice loss across Antarctica,[25]: 1264 although theEast Antarctic ice sheet continues to gain ice inland. By 2100, net ice loss from Antarctica is expected to add about 11 cm (5 in) to globalsea-level rise.Marine ice sheet instability may cause West Antarctica to contribute tens of centimeters more if it is triggered before 2100.[25]: 1270 With higher warming, instability would be much more likely, and could double global, 21st-century sea-level rise.[26][27][28]
Since the 1970s, the upper cell of the Southern Ocean overturning circulation has strengthened, while the lower cell weakened. These changes have been linked to the melting of the Antarctic ice sheet.
The freshmeltwater from the ice dilutes the salineAntarctic bottom water,[29][30] weakening the lower cell of theSouthern Ocean overturning circulation (SOOC).[25]: 1240 According to some research, a full collapse of the SOOC may occur at between 1.7 °C (3.1 °F) and 3 °C (5.4 °F) of global warming,[31] although the full effects are expected to occur over multiple centuries; these include less precipitation in theSouthern Hemisphere but more in theNorthern Hemisphere, an eventual decline of fisheries in the Southern Ocean and a potentialcollapse of certainmarine ecosystems.[32] While many Antarctic species remain undiscovered, there are documented increases inAntarctic flora,[33] and largefauna such aspenguins are already having difficulty retaining suitable habitat. On ice-free land,permafrost thaws releasegreenhouse gases and formerly frozen pollution.[34]
The West Antarctic ice sheet is likely to completely melt[35][36] unless temperatures are reduced by 2 °C (3.6 °F) below 2020 levels.[37] The loss of this ice sheet would take between 500 and 13,000 years.[38][39] A sea-level rise of 3.3 m (10 ft 10 in) would occur if the ice sheet collapses, leaving ice caps on the mountains, and 4.3 m (14 ft 1 in) if those ice caps also melt.[40] The far-stabler East Antarctic ice sheet may only cause a sea-level rise of 0.5 m (1 ft 8 in) – 0.9 m (2 ft 11 in) from the current level of warming, a small fraction of the 53.3 m (175 ft) contained in the full ice sheet.[41] With global warming of around 3 °C (5.4 °F), vulnerable areas likeWilkes Basin andAurora Basin may collapse over around 2,000 years,[38][39] potentially adding up to 6.4 m (21 ft 0 in) to sea levels.[42]
The first recorded sighting of Antarctica is credited to theSpaniardGabriel de Castilla, who reported seeing distant southern snow-capped mountains in 1603. The first Antarctic land discovered was the island ofSouth Georgia, visited by theEnglish merchantAnthony de la Roché in 1675.
Emilio Marcos Palma (born 7 January 1978) is an Argentine man who was the first documented person born on the continent of Antarctica at theEsperanza Base.[46] His father, Captain Jorge Palma, was head of the Argentine Army detachment at the base. While ten people have been born in Antarctica since, Palma's birthplace remains the southernmost. In late 1977, Silvia Morella de Palma, who was then seven months pregnant, was airlifted to Esperanza Base, in order to complete her pregnancy in the base. The airlift was a part of the Argentine solutions to the sovereignty dispute over territory in Antarctica. Emilio was automatically granted Argentine citizenship by the government since his parents were both Argentine citizens, and he was born in the claimedArgentine Antarctica. Palma can be considered to be the first native Antarctican.
The Antarctic region had noindigenous population when first discovered, and its present inhabitants comprise a few thousand transientscientific and other personnel working on tours of duty at the several dozenresearch stations maintained by various countries. However, the region is visited by more than 40,000[47] tourists annually, the most popular destinations being theAntarctic Peninsula area (especially theSouth Shetland Islands) andSouth Georgia Island.
In December 2009, the growth oftourism, with consequences for both the ecology and the safety of the travellers in its great and remote wilderness, was noted at a conference in New Zealand by experts from signatories to theAntarctic Treaty. The definitive results of the conference were presented at the Antarctic Treaty states' meeting in Uruguay in May 2010.[48]
Because Antarctica surrounds theSouth Pole, it is theoretically located in alltime zones. For practical purposes, time zones are usually based onterritorial claims or the time zone of a station's owner country or supply base.[49]
^The word was originally pronounced without the first/k/, but thespelling pronunciation has become common and is often considered more correct. The pronunciation without the first k sound and the first t sound is however widespread and a typical phenomenon of English in many other similar words too.[1] The "c" was added to the spelling for etymological reasons and then began to be pronounced, but (as with other spelling pronunciations) at first only by less educated people.[2][3]
^abcdFox-Kemper, B.;Hewitt, H.T.; Xiao, C.; Aðalgeirsdóttir, G.; Drijfhout, S.S.; Edwards, T.L.; Golledge, N.R.; Hemer, M.; Kopp, R.E.; Krinner, G.; Mix, A. (2021). Masson-Delmotte, V.; Zhai, P.; Pirani, A.; Connors, S.L.; Péan, C.; Berger, S.; Caud, N.; Chen, Y.; Goldfarb, L. (eds.)."Chapter 9: Ocean, Cryosphere and Sea Level Change"(PDF).Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, NY, USA:1270–1272.
^Horton, Benjamin P.; Khan, Nicole S.; Cahill, Niamh; Lee, Janice S. H.; Shaw, Timothy A.; Garner, Andra J.; Kemp, Andrew C.; Engelhart, Simon E.; Rahmstorf, Stefan (8 May 2020). "Estimating global mean sea-level rise and its uncertainties by 2100 and 2300 from an expert survey".npj Climate and Atmospheric Science.3 (1): 18.Bibcode:2020npCAS...3...18H.doi:10.1038/s41612-020-0121-5.hdl:10356/143900.S2CID218541055.
^Lenton, T. M.; Armstrong McKay, D.I.; Loriani, S.; Abrams, J.F.; Lade, S.J.; Donges, J.F.; Milkoreit, M.; Powell, T.; Smith, S.R.; Zimm, C.; Buxton, J.E.; Daube, Bruce C.; Krummel, Paul B.; Loh, Zoë; Luijkx, Ingrid T. (2023).The Global Tipping Points Report 2023 (Report). University of Exeter.
^Robinson, James (1906)."Appendix B: Log of theOffley". In Cerchi, D. (ed.). Reminiscences (Report). Hobart, Tasmania, AU: Archives Office of Tasmania. pp. 98–99. Archived fromthe original on 6 February 2012.
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