Antarctic Peninsula mapLocation of the Antarctic Peninsula withinAntarctica
The Antarctic Peninsula is part of the larger peninsula ofWest Antarctica, protruding 1,300 km (810 miles) from a line betweenCape Adams (Weddell Sea) and a point on the mainland south of theEklund Islands. Beneath the ice sheet that covers it, the Antarctic Peninsula consists of a string of bedrock islands; these are separated by deep channels whose bottoms lie at depths considerably below current sea level. They are joined by a grounded ice sheet.Tierra del Fuego, the southernmost tip ofSouth America, is about 1,000 km (620 miles) away across theDrake Passage.[1]
The Antarctic Peninsula is 522,000 square kilometres (202,000 sq mi) in area and 80% ice-covered.[2]
The marine ecosystem around the western continental shelf of the Antarctic Peninsula (WAP) has been subjected to rapidclimate change. Over the past 50 years, the warm, moist maritime climate of the northern WAP has shifted south. This climatic change increasingly displaces the once dominant cold, dry continental Antarctic climate. This regional warming has caused multi-level responses in the marine ecosystem such as increasedheat transport, decreased sea ice extent and duration, local declines in ice-dependentAdélie penguins, increase in ice-tolerant gentoo and chinstrap penguins, accelerated greening due to the spread of moss, alterations inphytoplankton andzooplankton community composition as well as changes inkrill recruitment, abundance and availability to predators.[3][4][5][6]
The Antarctic Peninsula is currently dotted with numerous research stations, and nations have made multiple claims ofsovereignty. The peninsula is part of disputed and overlapping claims byArgentina,Chile, and theUnited Kingdom. None of these claims have international recognition and, under theAntarctic Treaty System, the respective countries do not attempt to enforce their claims. The British claim, however, is recognised byAustralia,France,New Zealand, andNorway. Argentina has the most bases and personnel stationed on the peninsula.
Booth Island andMount Scott flank the narrowLemaire Channel on the west side of the Antarctic Peninsula, 2001.Off the coast of the Peninsula are numerous islands. Here isWebb Island and, behind it,Adelaide Island. See the image description page for a detailed description of the other geographical features.
The most likely first sighting of the Antarctic Peninsula, and therefore also of any part of the Antarctic mainland, was on 27 January 1820 by an expedition of theImperial Russian Navy led byFabian Gottlieb von Bellingshausen. But the party did not recognize as the mainland what they thought was anicefield covered by small hillocks.
Three days later, on 30 January 1820,Edward Bransfield andWilliam Smith, with a British expedition, were the first to chart part of the Antarctic Peninsula. This area was later to be calledTrinity Peninsula and is the extreme northeast portion of the peninsula. The next confirmed sighting was in 1832 byJohn Biscoe, a British explorer, who named the northern part of the Antarctic Peninsula asGraham Land.[1][7]
The first European to land on the continent is also disputed. A 19th-centuryseal hunter,John Davis, was almost certainly the first. But, sealers were secretive about their movements and theirlogbooks were deliberately unreliable, to protect any new sealing grounds from competition.[1]
Between 1901 and 1904,Otto Nordenskjöld led theSwedish Antarctic Expedition, one of the first expeditions to explore parts of Antarctica. They landed on the Antarctic Peninsula in February 1902, aboard the shipAntarctic, which sank not far from the peninsula. All crew were rescued by an Argentine ship. TheBritish Graham Land expedition between 1934 and 1937 carried out aerial surveys using ade Havilland Fox Moth aircraft, and concluded that Graham Land was not an archipelago but a peninsula.[1][7]
Agreement on the name "Antarctic Peninsula" by theAdvisory Committee on Antarctic Names andUK Antarctic Place-Names Committee in 1964 resolved a long-standing difference over the use of the United States' name"Palmer Peninsula" or the British name "Graham Land" for this geographic feature. This dispute was resolved by making Graham Land the part of the Antarctic Peninsula northward of a line betweenCape Jeremy andCape Agassiz; andPalmer Land the part southward of that line, which is roughly 69° S. Palmer Land is named for the United States seal hunterNathaniel Palmer. The Chilean name for the feature, O'Higgins Land, is in honor ofBernardo O'Higgins, the Chilean patriot and Antarctic visionary. Most other Spanish-speaking countries call itla Península Antártica, though Argentina also officially refers to this asTierra de San Martín; as of 2018 Argentina has more bases and personnel in the peninsula than any other nation.[1]
The 1950s saw a marked increase in the number of research bases as Britain, Chile and Argentina competed to make claims over the same area.[9] Meteorology and geology were the primary research subjects.
The grounding of the Argentine ship theARABahía Paraíso and subsequent 170,000 US gal (640,000 L; 140,000 imp gal)oil spill occurred near the Antarctic Peninsula in 1989.[11][12][13]
Geographic map of AntarcticaSatellite image of Antarctic PeninsulaRelief map
The peninsula is very mountainous, its highest peaks rising to about 2,800 m (9,200 ft). Notable peaks on the peninsula includeDeschanel Peak,Mounts Castro,Coman,Gilbert,Jackson,William,Owen,Scott, andHope, which is the highest point at 3,239 m (10,627 ft),[15]Mount William,Mount Owen andMount Scott. These mountains are considered to be a continuation of theAndes ofSouth America, with a submarine spine orridge connecting the two.[16] This is the basis for the position advanced by Chile and Argentina for their territorial claims. TheScotia Arc is the island arc system that links the mountains of the Antarctic Peninsula to those ofTierra del Fuego.
In March 2025, scientists reported the discovery of a thriving marine ecosystem under where a 500-foot-thick (150 m) iceberg the size of Chicago had been before breaking off from theGeorge VI Ice Shelf around 2020. More than 4,250 feet (1,300 m) below, the seafloor showed a flourishing ecosystem including several new species scientists discovered during their research.[19]
Nearly cloud-free view of the northern tip of the Antarctic Peninsula during springHope Bay glacier, 2012
Because the Antarctic Peninsula, which reaches north of theAntarctic Circle, is the most northerly part of Antarctica, it has the mildest climates within this continent. Its climate is therefore classified as atundra, rather than anice cap. Its temperatures are warmest in January, averaging 1 to 2 °C (34 to 36 °F), and coldest in June, averages from −15 to −20 °C (5 to −4 °F). Its west coast from the tip of the Antarctic Peninsula south to68° S, which has a maritime Antarctic climate, is the mildest part of the Antarctic Peninsula. Within this part of the Antarctic Peninsula, temperatures exceed 0 °C (32 °F) for 3 or 4 months during the summer, and rarely fall below −10 °C (14 °F) during the winter. Farther south along the west coast and the northeast coast of the peninsula, mean monthly temperatures exceed 0 °C (32 °F) for only one or two months of summer and average around −15 °C (5 °F) in winter. The east coast of the Antarctic Peninsula south of63° S is generally much colder, with mean temperatures exceeding 0 °C (32 °F) for at most one month of summer, and winter mean temperatures ranging from −5 to −25 °C (23 to −13 °F). The colder temperatures of the southeast, Weddell Sea side, of the Antarctic Peninsula are reflected in the persistence of ice shelves that cling to the eastern side.[20][21]
Precipitation varies greatly within the Antarctic Peninsula. From the tip of the Antarctic Peninsula to 68° S, precipitation averages 35–50 cm (14–20 in) per year. A good portion of this precipitation falls as rain during the summer, on two-thirds of the days of the year, and with little seasonal variation in amounts. Between about 68° S and 63° S on the west coast of the Antarctic Peninsula and along its northeast coast, precipitation is 35 cm (14 in) or less with occasional rain. Along the east coast of the Antarctic Peninsula south of 63° S, precipitation ranges from 10 to 15 cm (3.9 to 5.9 in). In comparison, thesubantarctic islands have precipitation of 100–200 cm (39–79 in) per year and the dry interior of Antarctica is a virtual desert with only 10 cm (3.9 in) precipitation per year.[21]
The climate in and around the Antarctic Peninsula is changing dramatically in 2024. The most recent[clarification needed] temperature recorded was 10°C, which is higher than the peninsula region's average and deviates from the patterns of typical temperatures. The peninsula is getting very much affected by these sudden climate changes. In past years, researchers have seen northwesterly winds over the peninsula, and it is proven that this is one of the reasons for the peninsula constantly melting and snow sublimation in 2024. Researchers are observing similar situations in 2024. Melting events have been observed on the eastern and western sides of the Peninsula in February and March. All three are contributing to the melting of ice in several Antarctic Peninsula areas, such as Larsen C and B. Furthermore, data from NASA's research indicates that the ice sheet is melting nonstop.[22][23]
Because of issues concerning global climate change, the Antarctic Peninsula and adjacent parts of theWeddell Sea and its Pacificcontinental shelf have been the subject of intensive geologic, paleontologic, and paleoclimatic research by interdisciplinary and multinational groups over the last several decades. The combined study of theglaciology of itsice sheet and thepaleontology,sedimentology,stratigraphy,structural geology, andvolcanology ofglacial and nonglacial deposits of the Antarctic Peninsula has allowed the reconstruction of thepaleoclimatology and prehistoric ice sheet fluctuation of it for over the last 100 million years. This research shows the dramatic changes in climate, which have occurred within this region after it reached its approximate position within the Antarctic Circle during theCretaceous Period.[24][25][26][27][28]
TheFossil Bluff Group, which outcrops withinAlexander Island, provides a detailed record, which includespaleosols andfossil plants, of Middle Cretaceous (Albian) terrestrial climates. Thesediments that form the Fossil Bluff Group accumulated within avolcanic island arc, which now forms thebedrock backbone of the Antarctic Peninsula, in prehistoricfloodplains anddeltas and offshore assubmarine fans and other marine sediments. As reflected in the plant fossils, paleosols, and climate models, the climate was warm, humid, and seasonally dry. According to climate models, the summers were dry and winters were wet. The rivers were perennial and subject to intermittent flooding as the result of heavy rainfall.[26][29]
Warm high-latitude climates reached a peak during the mid-Late CretaceousCretaceous Thermal Maximum. Plant fossils found within the Late Cretaceous (Coniacian andSantonian-earlyCampanian) strata of the Hidden Lake and Santa Maria formations, which outcrop withinJames Ross,Seymour, and adjacent islands, indicate that this emergent volcanic island arc enjoyed warm temperate orsubtropical climates with adequate moisture for growth and without extended periods of below freezing winter temperatures.[26][30]
After the peak warmth of the Cretaceous thermal maximum the climate, both regionally and globally, appears to have cooled as seen in the Antarctic fossil wood record. Later, warm high-latitude climates returned to the Antarctic Peninsula region during thePaleocene and earlyEocene as reflected in fossil plants. Abundant plant and marine fossils from Paleogene marine sediments that outcrop on Seymour Island indicate the presence of cool and moist, high-latitudes environment during the early Eocene.[24][26]
Detailed studies of the paleontology, sedimentology, and stratigraphy of glacial and nonglacial deposits within the Antarctic Peninsula and adjacent parts of the Weddell Sea and its Pacific continental shelf have found that it has become progressively glaciated as the climate of Antarctica dramatically and progressively cooled during the last 37 million years. This progressive cooling was contemporaneous with a reduction inatmospheric CO2 concentrations. During this climatic cooling, the Antarctic Peninsula was probably the last region of Antarctica to have been fullyglaciated. Within the Antarctic Peninsula, mountain glaciation was initiated during the latest Eocene, about 37–34 Ma. The transition from temperate, alpine glaciation to a dynamic ice sheet occurred about 12.8 Ma. At this time, the Antarctic Peninsula formed as the bedrock islands underlying it were overridden and joined by an ice sheet in the earlyPliocene about 5.3–3.6 Ma. During theQuaternary period, the size of the West Antarctic Ice Sheet has fluctuated in response to glacial–interglacial cycles. During glacial epochs, this ice sheet was significantly thicker than it is currently and extended to the edge of the continental shelves. Duringinterglacial epochs, the West Antarctica Ice Sheet was thinner than during glacial epochs and its margins lay significantly inland of the continental margins.[24][25][26]
During theLast Glacial Maximum, about 20,000 to 18,000 years ago, the ice sheet covering the Antarctic Peninsula was significantly thicker than it is now. Except for a few isolatednunataks, the Antarctic Peninsula and its associated islands were completely buried by the ice sheet. In addition, the ice sheet extended past the present shoreline onto the Pacific outer continental shelf and completely filled the Weddell Sea up to the continental margin with grounded ice.[24][27][28][31]
Thedeglaciation of the Antarctic Peninsula largely occurred between 18,000 and 6,000 years ago as aninterglacial climate was established in the region. It initially started about 18,000 to 14,000 years ago with retreat of the ice sheet from the Pacific outer continental shelf and the continental margin within the Weddell Sea. Within the Weddell Sea, the transition from grounded ice to a floating ice shelf occurred about 10,000 years ago. The deglaciation of some locations within the Antarctic Peninsula continued until 4,000 to 3,000 years ago. Within the Antarctic Peninsula, an interglacial climatic optimum occurred about 3,000 to 5,000 years ago. After the climate optimum, a distinct climate cooling, which lasted until historic times, occurred.[27][28][31][32]
The Antarctic Peninsula is a part of the world that is experiencing extraordinary warming.[33] Each decade for the last five, average temperatures in the Antarctic Peninsula have risen by 0.5 °C (0.90 °F).[34] Ice mass loss on the peninsula occurred at a rate of 60 billion tons / year in 2006,[35] with the greatest change occurring in the northern tip of the peninsula.[36] Seven ice shelves along the Antarctic Peninsula have retreated or disintegrated in the last two decades.[33] Research by theUnited States Geological Survey has revealed that every ice front on the southern half of the peninsula experienced a retreat between 1947 and 2009.[37] According to a study by theBritish Antarctic Survey, glaciers on the peninsula are not only retreating but also increasing their flow rate as a result of increasedbuoyancy in the lower parts of the glaciers.[38] Professor David Vaughan has described the disintegration of the Wilkins Ice Shelf as the latest evidence of rapid warming in the area.[39] TheIntergovernmental Panel on Climate Change has been unable to determine the greatest potential effect onsea level rise that glaciers in the region may cause.[38]
TheAntarctic fur seal, once reduced to a small population onSouth Georgia after being hunted towards extinction, has returned to the waters around the Antarctic Peninsula.Adélie penguins, 2012
The coasts of the peninsula have the mildest climate in Antarctica andmoss andlichen-covered rocks are free of snow during the summer months, although the weather is still intensely cold and the growing season very short. The plant life today is mainly mosses, lichens andalgae adapted to this harsh environment, with lichens preferring the wetter areas of the rocky landscape. The most common lichens areUsnea andBryoria species. Antarctica's two flowering plant species, theAntarctic hair grass (Deschampsia antarctica) andAntarctic pearlwort (Colobanthus quitensis) are found on the northern and western parts of the Antarctic Peninsula, including offshore islands, where the climate is relatively mild.Lagotellerie Island inMarguerite Bay is an example of this habitat.[20][21][40]
Antarctic krill are found in the seas surrounding the peninsula and the rest of the continent. Thecrabeater seal spends most of its life in the same waters feeding on krill.Bald notothen is acryopelagic fish that lives in sub-zero water temperatures around the peninsula. Vocalizations of thesei whale can be heard emanating from the waters surrounding the Antarctic Peninsula.[20]
Penguin species found on the peninsula, especially near the tip and surrounding islands, include thechinstrap penguin,emperor penguin,gentoo penguin and theAdélie penguin.Petermann Island is the world's southernmost colony of gentoo penguins. The exposed rocks on the island is one of many locations on the peninsula that provides a good habitat forrookeries. The penguins return each year and may reach populations of more than ten thousand. Of these the most common on the Antarctic Peninsula are the chinstrap and gentoo, with the only breeding colony of emperor penguins in West Antarctica an isolated population on theDion Islands, inMarguerite Bay on the west coast of the peninsula. Most emperor penguins breed in East Antarctica.[20][21][40]
Although this very remote part of the world has never been inhabited and is protected by theAntarctic Treaty System, which bans industrial development, waste disposal and nuclear testing, there is still a threat to these fragile ecosystems from increasing tourism, primarily on cruises across theSouthern Ocean from the port ofUshuaia,Argentina.
A rich record of fossil leaves, wood, pollen, and flowers demonstrates that flowering plants thrived in subtropical climates within the volcanic island arcs that occupied the Antarctic Peninsula region during the Cretaceous and very early Paleogene periods. The analysis of fossil leaves and flowers indicates that semitropical woodlands, which were composed of ancestors of plants that live in the tropics today, thrived within this region during a global thermal maximum with summer temperatures that averaged 20 °C (68 °F).
The oldest fossil plants come from the middle Cretaceous (Albian) Fossil Bluff Group, which outcrop along the edge of Alexander Island. These fossils reveal that at this time the forests consisted of largeconifers, with mosses and ferns in the undergrowth. The paleosols, in which trees are rooted, have physical characteristics indicative of modern soils that form under seasonally dry climates with periodic high rainfall.[29] Younger Cretaceous strata, which outcrop within James Ross, Seymour, and adjacent islands, contain fossil plants of Late Cretaceousangiosperms with leaf morphotypes that are similar to those of living families such as Sterculiaceae, Lauraceae, Winteraceae, Cunoniaceae, and Myrtaceae. They indicate that the emergent parts of the volcanic island arc, the eroded roots of which now form the central part of the Antarctic Peninsula, were covered by either warm temperate or subtropical forests.[30]
These fossil plants are indicative of tropical and subtropical forest at high paleolatitudes during the Middle and Late Cretaceous, which grew in climates without extended periods of below freezing winter temperatures and with adequate moisture for growth.[26] The Cretaceous strata of James Ross Island also yielded thedinosaur genusAntarctopelta, which was the first dinosaur fossil to be found on Antarctica.[42]
Paleogene and Early Eocene marine sediments that outcrop on Seymour Island contain plant-rich horizons. The fossil plants are dominated by permineralized branches of conifers and compressions of angiosperm leaves, and are found within carbonate concretions. These Seymour Island region fossils date to about 51.5–49.5 Ma and are dominated by leaves, cone scales, and leafy branches of Araucarian conifers, very similar in all respects to livingAraucaria araucana (monkey puzzle) from Chile. They suggest that the adjacent parts of the prehistoric Antarctic Peninsula were covered by forests that grew in a cool and moist, high-latitude environment during the early Eocene.[26]
During the Cenozoic climatic cooling, the Antarctic Peninsula was the last region of Antarctica to have been fully glaciated according to current research. As a result, this region was probably the last refugium for plants and animals that had inhabited Antarctica after it separated from theGondwanaland supercontinent.
Analysis of paleontologic, stratigraphic, and sedimentologic data acquired from the study of drill core and seismic acquired during the Shallow Drilling on the Antarctic Continental Shelf (SHALDRIL) and other projects and from fossil collections from and rock outcrops within Alexander, James Ross, King George, Seymour, andSouth Shetland Islands has yielded a record of the changes in terrestrial vegetation that occurred within the Antarctic Peninsula over the course of the past 37 million years.[25][26]
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