Arctic shelf
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The Arctic Ocean is the smallest and shallowest of the world's five major
ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wo ...
s. It spans an area of approximately and is known as the coldest of all the oceans. The
International Hydrographic Organization The International Hydrographic Organization (IHO) is an intergovernmental organisation representing hydrography. , the IHO comprised 98 Member States. A principal aim of the IHO is to ensure that the world's seas, oceans and navigable waters a ...
(IHO) recognizes it as an ocean, although some
oceanographers Oceanography (), also known as oceanology and ocean science, is the scientific study of the oceans. It is an Earth science, which covers a wide range of topics, including ecosystem dynamics; ocean currents, Wind wave, waves, and geophysical flu ...
call it the Arctic Mediterranean Sea. It has been described approximately as an
estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...
of the
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
. It is also seen as the northernmost part of the all-encompassing
World Ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the worl ...
. The Arctic Ocean includes the
North Pole The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where the Earth's axis of rotation meets its surface. It is called the True North Pole to distinguish from the Mag ...
region in the middle of the Northern Hemisphere and extends south to about 60°N. The Arctic Ocean is surrounded by
Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago a ...
and
North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
, and the borders follow topographic features: the Bering Strait on the Pacific side and the Greenland Scotland Ridge on the Atlantic side. It is mostly covered by
sea ice Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oce ...
throughout the year and almost completely in
winter Winter is the coldest season of the year in polar and temperate climates. It occurs after autumn and before spring. The tilt of Earth's axis causes seasons; winter occurs when a hemisphere is oriented away from the Sun. Different cultures ...
. The Arctic Ocean's surface temperature and
salinity Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...
vary seasonally as the
ice cover Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oc ...
melts and freezes; its salinity is the lowest on average of the five major oceans, due to low
evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...
, heavy
fresh water Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
inflow from rivers and streams, and limited connection and outflow to surrounding oceanic waters with higher salinities. The summer shrinking of the ice has been quoted at 50%. The US
National Snow and Ice Data Center The National Snow and Ice Data Center (NSIDC) is a United States information and referral center in support of polar and cryospheric research. NSIDC archives and distributes digital and analog snow and ice data and also maintains information abo ...
(NSIDC) uses satellite data to provide a daily record of Arctic sea ice cover and the rate of melting compared to an average period and specific past years, showing a continuous decline in sea ice extent. In September 2012, the Arctic ice extent reached a new record minimum. Compared to the average extent (1979–2000), the sea ice had diminished by 49%.


History


North America

Human habitation in the North American polar region goes back at least 17,000–50,000 years, during the
Wisconsin glaciation The Wisconsin Glacial Episode, also called the Wisconsin glaciation, was the most recent glacial period of the North American ice sheet complex. This advance included the Cordilleran Ice Sheet, which nucleated in the northern North American Cor ...
. At this time, falling
sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised g ...
s allowed people to move across the
Bering land bridge Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 72 degrees north latitude in the Chukchi Sea; and on the south by the tip of ...
that joined
Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...
to northwestern North America (Alaska), leading to the
Settlement of the Americas The settlement of the Americas began when Paleolithic hunter-gatherers entered North America from the North Asian Mammoth steppe via the Beringia land bridge, which had formed between northeastern Siberia and western Alaska due to the lowering of ...
. Early Paleo-Eskimo groups included the
Pre-Dorset The Pre-Dorset is a loosely defined term for a Paleo-Eskimo culture or group of cultures that existed in the Eastern Canadian Arctic from c. 3200 to 850 cal BC, and preceded the Dorset culture. Due to its vast geographical expanse and to history ...
(); the
Saqqaq culture The Saqqaq culture (named after the Saqqaq settlement, the site of many archaeological finds) was a Paleo-Eskimo culture in southern Greenland. Up to this day, no other people seem to have lived in Greenland continually for as long as the Saqqaq. ...
of Greenland (2500–800 BC); the Independence I and
Independence II culture Independence II was a Paleo-Eskimo culture that flourished in northern and northeastern Greenland from around 700 to 80 BC, north and south of the Independence Fjord. The Independence II culture existed in roughly the same areas of Greenland as th ...
s of northeastern
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
and
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
( and ); and the Groswater of
Labrador , nickname = "The Big Land" , etymology = , subdivision_type = Country , subdivision_name = Canada , subdivision_type1 = Province , subdivision_name1 ...
and
Nunavik Nunavik (; ; iu, ᓄᓇᕕᒃ) comprises the northern third of the province of Quebec, part of the Nord-du-Québec region and nearly coterminous with Kativik. Covering a land area of north of the 55th parallel, it is the homeland of the I ...
. The
Dorset culture The Dorset was a Paleo-Eskimo culture, lasting from to between and , that followed the Pre-Dorset and preceded the Thule people (proto-Inuit) in the North American Arctic. The culture and people are named after Cape Dorset (now Kinngait) in N ...
spread across Arctic North America between 500 BC and AD 1500. The Dorset were the last major Paleo-Eskimo culture in the Arctic before the migration east from present-day
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
of the
Thule Thule ( grc-gre, Θούλη, Thoúlē; la, Thūlē) is the most northerly location mentioned in ancient Greek literature, ancient Greek and Latin literature, Roman literature and cartography. Modern interpretations have included Orkney, Shet ...
, the ancestors of the modern Inuit. The
Thule Tradition The Thule (, , ) or proto-Inuit were the ancestors of all modern Inuit. They developed in coastal Alaska by the year 1000 and expanded eastward across northern Canada, reaching Greenland by the 13th century. In the process, they replaced people o ...
lasted from about 200 BC to AD 1600, arising around the Bering Strait and later encompassing almost the entire Arctic region of North America. The Thule people were the ancestors of the
Inuit Inuit (; iu, ᐃᓄᐃᑦ 'the people', singular: Inuk, , dual: Inuuk, ) are a group of culturally similar indigenous peoples inhabiting the Arctic and subarctic regions of Greenland, Labrador, Quebec, Nunavut, the Northwest Territories ...
, who now live in
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
,
Northwest Territories The Northwest Territories (abbreviated ''NT'' or ''NWT''; french: Territoires du Nord-Ouest, formerly ''North-Western Territory'' and ''North-West Territories'' and namely shortened as ''Northwest Territory'') is a federal territory of Canada. ...
,
Nunavut Nunavut ( , ; iu, ᓄᓇᕗᑦ , ; ) is the largest and northernmost Provinces and territories of Canada#Territories, territory of Canada. It was separated officially from the Northwest Territories on April 1, 1999, via the ''Nunavut Act'' ...
,
northern Quebec Northern Quebec (french: le nord du Québec) is a geographic term denoting the northerly, more remote and less populated parts of the Canadian province of Quebec.Alexandre Robaey"Charity group works with Indigenous communities to feed Northern Quebe ...
,
Labrador , nickname = "The Big Land" , etymology = , subdivision_type = Country , subdivision_name = Canada , subdivision_type1 = Province , subdivision_name1 ...
and
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
.


Europe

For much of
European history The history of Europe is traditionally divided into four time periods: prehistoric Europe (prior to about 800 BC), classical antiquity (800 BC to AD 500), the Middle Ages (AD 500 to AD 1500), and the modern era (since AD 1500). The first early ...
, the north
polar region The polar regions, also called the frigid geographical zone, zones or polar zones, of Earth are the regions of the planet that surround its geographical poles (the North Pole, North and South Poles), lying within the polar circles. These high l ...
s remained largely unexplored and their geography conjectural.
Pytheas Pytheas of Massalia (; Ancient Greek: Πυθέας ὁ Μασσαλιώτης ''Pythéas ho Massaliōtēs''; Latin: ''Pytheas Massiliensis''; born 350 BC, 320–306 BC) was a Greeks, Greek List of Graeco-Roman geographers, geographer, explor ...
of
Massilia Massalia (Greek: Μασσαλία; Latin: Massilia; modern Marseille) was an ancient Greek colony founded ca. 600 BC on the Mediterranean coast of present-day France, east of the river Rhône, by Ionian Greek settlers from Phocaea, in Western An ...
recorded an account of a journey northward in 325 BC, to a land he called " Eschate Thule", where the Sun only set for three hours each day and the water was replaced by a congealed substance "on which one can neither walk nor sail". He was probably describing loose sea ice known today as " growlers" or "bergy bits"; his "Thule" was probably
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
, though the
Faroe Islands The Faroe Islands ( ), or simply the Faroes ( fo, Føroyar ; da, Færøerne ), are a North Atlantic island group and an autonomous territory of the Kingdom of Denmark. They are located north-northwest of Scotland, and about halfway bet ...
or
Shetland Shetland, also called the Shetland Islands and formerly Zetland, is a subarctic archipelago in Scotland lying between Orkney, the Faroe Islands and Norway. It is the northernmost region of the United Kingdom. The islands lie about to the no ...
have also been suggested. Early
cartographers Cartography (; from grc, χάρτης , "papyrus, sheet of paper, map"; and , "write") is the study and practice of making and using maps. Combining science, aesthetics and technique, cartography builds on the premise that reality (or an im ...
were unsure whether to draw the region around the North Pole as land (as in
Johannes Ruysch Johannes Ruysch (c. 1460? in Utrecht – 1533 in Cologne), a.k.a. ''Johann Ruijsch'' or ''Giovanni Ruisch'' was an explorer, cartographer, astronomer, manuscript illustrator and painter from the Low Countries who produced a famous map of the world ...
's map of 1507, or
Gerardus Mercator Gerardus Mercator (; 5 March 1512 – 2 December 1594) was a 16th-century geographer, cosmographer and Cartography, cartographer from the County of Flanders. He is most renowned for creating the Mercator 1569 world map, 1569 world map based on ...
's map of 1595) or water (as with
Martin Waldseemüller Martin Waldseemüller (c. 1470 – 16 March 1520) was a German cartographer and humanist scholar. Sometimes known by the Latinisation of names, Latinized form of his name, Hylacomylus, his work was influential among contemporary cartographers. He ...
's world map of 1507). The fervent desire of European merchants for a northern passage, the
Northern Sea Route The Northern Sea Route (NSR) (russian: Се́верный морско́й путь, ''Severnyy morskoy put'', shortened to Севморпуть, ''Sevmorput'') is a shipping route officially defined by Russian legislation as lying east of Nov ...
or the
Northwest Passage The Northwest Passage (NWP) is the sea route between the Atlantic and Pacific oceans through the Arctic Ocean, along the northern coast of North America via waterways through the Canadian Arctic Archipelago. The eastern route along the Arct ...
, to "
Cathay Cathay (; ) is a historical name for China that was used in Europe. During the early modern period, the term ''Cathay'' initially evolved as a term referring to what is now Northern China, completely separate and distinct from China, which ...
" (
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
) caused water to win out, and by 1723 mapmakers such as
Johann Homann Johann Baptist Homann (20 March 1664 – 1 July 1724) was a German geographer and cartographer, who also made maps of the Americas. Life Homann was born in Oberkammlach near Kammlach in the Electorate of Bavaria. Although educated at a Jesui ...
featured an extensive "Oceanus Septentrionalis" at the northern edge of their charts. The few expeditions to penetrate much beyond the
Arctic Circle The Arctic Circle is one of the two polar circles, and the most northerly of the five major circles of latitude as shown on maps of Earth. Its southern equivalent is the Antarctic Circle. The Arctic Circle marks the southernmost latitude at w ...
in that era added only small islands, such as
Novaya Zemlya Novaya Zemlya (, also , ; rus, Но́вая Земля́, p=ˈnovəjə zʲɪmˈlʲa, ) is an archipelago in northern Russia. It is situated in the Arctic Ocean, in the extreme northeast of Europe, with Cape Flissingsky, on the northern island, ...
(11th century) and
Spitzbergen Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...
(1596), though, since these were often surrounded by
pack-ice Drift ice, also called brash ice, is sea ice that is not attached to the shoreline or any other fixed object (shoals, grounded icebergs, etc.).Leppäranta, M. 2011. The Drift of Sea Ice. Berlin: Springer-Verlag. Unlike fast ice, which is "fastene ...
, their northern limits were not so clear. The makers of navigational charts, more conservative than some of the more fanciful cartographers, tended to leave the region blank, with only fragments of known coastline sketched in.


19th century

This lack of knowledge of what lay north of the shifting barrier of ice gave rise to a number of conjectures. In England and other European nations, the
myth Myth is a folklore genre consisting of Narrative, narratives that play a fundamental role in a society, such as foundational tales or Origin myth, origin myths. Since "myth" is widely used to imply that a story is not Objectivity (philosophy), ...
of an "
Open Polar Sea The Open Polar Sea was a hypothesized ice-free ocean surrounding the North Pole. This unproved and eventually-disproved theory was once so widely believed that many exploring expeditions used it as justification for attempts to reach the North P ...
" was persistent. John Barrow, longtime Second Secretary of the
British Admiralty The Admiralty was a department of the Government of the United Kingdom responsible for the command of the Royal Navy until 1964, historically under its titular head, the Lord High Admiral – one of the Great Officers of State. For much of it ...
, promoted exploration of the region from 1818 to 1845 in search of this. In the United States in the 1850s and 1860s, the explorers
Elisha Kane Elisha Kent Kane (February 3, 1820 – February 16, 1857) was a United States Navy medical officer and Arctic explorer. He served as assistant surgeon during Caleb Cushing's journey to China to negotiate the Treaty of Wangxia and in the Af ...
and
Isaac Israel Hayes Isaac Israel Hayes (March 5, 1832 – December 17, 1881) was an American Arctic explorer, physician, and politician, who was appointed as the commanding officer at Satterlee General Hospital during the American Civil War, and was then elected, ...
both claimed to have seen part of this elusive body of water. Even quite late in the century, the eminent authority
Matthew Fontaine Maury Matthew Fontaine Maury (January 14, 1806February 1, 1873) was an American oceanographer and naval officer, serving the United States and then joining the Confederacy during the American Civil War. He was nicknamed "Pathfinder of the Seas" and i ...
included a description of the Open Polar Sea in his textbook ''The Physical Geography of the Sea'' (1883). Nevertheless, as all the explorers who travelled closer and closer to the pole reported, the
polar ice cap A polar ice cap or polar cap is a high-latitude region of a planet, dwarf planet, or natural satellite that is covered in ice. There are no requirements with respect to size or composition for a body of ice to be termed a polar ice cap, nor a ...
is quite thick and persists year-round.
Fridtjof Nansen Fridtjof Wedel-Jarlsberg Nansen (; 10 October 186113 May 1930) was a Norwegian polymath and Nobel Peace Prize laureate. He gained prominence at various points in his life as an explorer, scientist, diplomat, and humanitarian. He led the team t ...
was the first to make a
nautical Seamanship is the art, knowledge and competence of operating a ship, boat or other craft on water. The'' Oxford Dictionary'' states that seamanship is "The skill, techniques, or practice of handling a ship or boat at sea." It involves topics a ...
crossing of the Arctic Ocean, in 1896.


20th century

The first surface crossing of the ocean was led by
Wally Herbert Sir Walter William Herbert (24 October 1934 – 12 June 2007) was a British polar explorer, writer and artist. In 1969 he became the first man fully recognized for walking to the North Pole, on the 60th anniversary of Robert Peary's disputed exp ...
in 1969, in a
dog sled A dog sled or dog sleigh is a sled pulled by one or more sled dogs used to travel over ice and through snow. Numerous types of sleds are used, depending on their function. They can be used for dog sled racing. Traditionally in Greenland and the e ...
expedition from
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
to
Svalbard Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...
, with air support. The first nautical transit of the north pole was made in 1958 by the submarine USS ''Nautilus'', and the first surface nautical transit occurred in 1977 by the
icebreaker An icebreaker is a special-purpose ship or boat designed to move and navigate through ice-covered waters, and provide safe waterways for other boats and ships. Although the term usually refers to ice-breaking ships, it may also refer to smaller ...
NS ''Arktika''. Since 1937,
Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
and Russian manned
drifting ice station A drifting ice station is a temporary or semi-permanent facility built on an ice floe. During the Cold War the Soviet Union and the United States maintained a number of stations in the Arctic Ocean on floes such as Fletcher's Ice Island for rese ...
s have extensively monitored the Arctic Ocean. Scientific settlements were established on the drift ice and carried thousands of kilometres by
ice floe An ice floe () is a large pack of floating ice often defined as a flat piece at least 20 m across at its widest point, and up to more than 10 km across. Drift ice is a floating field of sea ice composed of several ice floes. They may caus ...
s. In
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, the European region of the Arctic Ocean was heavily contested: the Allied commitment to resupply the Soviet Union via its northern ports was opposed by German naval and air forces. Since 1954 commercial airlines have flown over the Arctic Ocean (see
Polar route A polar route is an aircraft route across the uninhabited polar ice cap regions. The term "polar route" was originally applied to great circle navigation routes between Europe and the west coast of North America in the 1950s. The Arctic Early ye ...
).


Geography


Size

The Arctic Ocean occupies a roughly circular basin and covers an area of about , almost the size of
Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
. The coastline is long. It is the only
ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wo ...
smaller than
Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
, which has a land area of .


Surrounding land and exclusive economic zones

The Arctic Ocean is surrounded by the land masses of Eurasia (
Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
and
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
), North America (
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
and the U.S. state of
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
),
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
, and
Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
. Note: Some parts of the areas listed in the table are located in the
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
. Other consists of
Gulf A gulf is a large inlet from the ocean into the landmass, typically with a narrower opening than a bay, but that is not observable in all geographic areas so named. The term gulf was traditionally used for large highly-indented navigable bodie ...
s,
Strait A strait is an oceanic landform connecting two seas or two other large areas of water. The surface water generally flows at the same elevation on both sides and through the strait in either direction. Most commonly, it is a narrow ocean channe ...
s,
Channel Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Austral ...
s and other parts without specific names and excludes Exclusive Economic Zones.


Subareas and connections

The Arctic Ocean is connected to the
Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
by the Bering Strait and to the Atlantic Ocean through the
Greenland Sea The Greenland Sea is a body of water that borders Greenland to the west, the Svalbard archipelago to the east, Fram Strait and the Arctic Ocean to the north, and the Norwegian Sea and Iceland to the south. The Greenland Sea is often defined as p ...
and
Labrador Sea The Labrador Sea (French: ''mer du Labrador'', Danish: ''Labradorhavet'') is an arm of the North Atlantic Ocean between the Labrador Peninsula and Greenland. The sea is flanked by continental shelf, continental shelves to the southwest, northwest, ...
. (The Iceland Sea is sometimes considered part of the
Greenland Sea The Greenland Sea is a body of water that borders Greenland to the west, the Svalbard archipelago to the east, Fram Strait and the Arctic Ocean to the north, and the Norwegian Sea and Iceland to the south. The Greenland Sea is often defined as p ...
, and sometimes separate.) The largest seas in the Arctic Ocean: #
Barents Sea The Barents Sea ( , also ; no, Barentshavet, ; russian: Баренцево море, Barentsevo More) is a marginal sea of the Arctic Ocean, located off the northern coasts of Norway and Russia and divided between Norwegian and Russian territo ...
—1.4 million km2 #
Hudson Bay Hudson Bay ( crj, text=ᐐᓂᐯᒄ, translit=Wînipekw; crl, text=ᐐᓂᐹᒄ, translit=Wînipâkw; iu, text=ᑲᖏᖅᓱᐊᓗᒃ ᐃᓗᐊ, translit=Kangiqsualuk ilua or iu, text=ᑕᓯᐅᔭᕐᔪᐊᖅ, translit=Tasiujarjuaq; french: b ...
—1.23 million km2 (sometimes not included) #
Greenland Sea The Greenland Sea is a body of water that borders Greenland to the west, the Svalbard archipelago to the east, Fram Strait and the Arctic Ocean to the north, and the Norwegian Sea and Iceland to the south. The Greenland Sea is often defined as p ...
—1.205 million km2 #
East Siberian Sea The East Siberian Sea ( rus, Восто́чно-Сиби́рское мо́ре, r=Vostochno-Sibirskoye more) is a marginal sea in the Arctic Ocean. It is located between the Arctic Cape to the north, the coast of Siberia to the south, the New Si ...
—987,000 km2 #
Kara Sea The Kara Sea (russian: Ка́рское мо́ре, ''Karskoye more'') is a marginal sea, separated from the Barents Sea to the west by the Kara Strait and Novaya Zemlya, and from the Laptev Sea to the east by the Severnaya Zemlya archipelago. ...
—926,000 km2 #
Laptev Sea The Laptev Sea ( rus, мо́ре Ла́птевых, r=more Laptevykh; sah, Лаптевтар байҕаллара, translit=Laptevtar baỹğallara) is a marginal sea of the Arctic Ocean. It is located between the northern coast of Siberia, th ...
—662,000 km2 #
Chukchi Sea Chukchi Sea ( rus, Чуко́тское мо́ре, r=Chukotskoye more, p=tɕʊˈkotskəjə ˈmorʲɪ), sometimes referred to as the Chuuk Sea, Chukotsk Sea or the Sea of Chukotsk, is a marginal sea of the Arctic Ocean. It is bounded on the west b ...
—620,000 km2 #
Beaufort Sea The Beaufort Sea (; french: Mer de Beaufort, Iñupiaq: ''Taġiuq'') is a marginal sea of the Arctic Ocean, located north of the Northwest Territories, the Yukon, and Alaska, and west of Canada's Arctic islands. The sea is named after Sir Fr ...
—476,000 km2 # Amundsen Gulf # White Sea—90,000 km2 # Pechora Sea—81,263 km2 # Lincoln Sea—64,000 km2 # Prince Gustaf Adolf Sea # Queen Victoria Sea # Wandel Sea Different authorities put various marginal seas in either the Arctic Ocean or the Atlantic Ocean, including:
Hudson Bay Hudson Bay ( crj, text=ᐐᓂᐯᒄ, translit=Wînipekw; crl, text=ᐐᓂᐹᒄ, translit=Wînipâkw; iu, text=ᑲᖏᖅᓱᐊᓗᒃ ᐃᓗᐊ, translit=Kangiqsualuk ilua or iu, text=ᑕᓯᐅᔭᕐᔪᐊᖅ, translit=Tasiujarjuaq; french: b ...
, Baffin Bay, the Norwegian Sea, and Hudson Strait.


Islands

The main islands and archipelagos in the Arctic Ocean are, from the prime meridian west: * Jan Mayen (Norway) *
Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
*
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
* Arctic Archipelago (Canada, includes the Queen Elizabeth Islands and Baffin Island) * Wrangel Island (Russia) * New Siberian Islands (Russia) * Severnaya Zemlya (Russia) *
Novaya Zemlya Novaya Zemlya (, also , ; rus, Но́вая Земля́, p=ˈnovəjə zʲɪmˈlʲa, ) is an archipelago in northern Russia. It is situated in the Arctic Ocean, in the extreme northeast of Europe, with Cape Flissingsky, on the northern island, ...
(Russia, includes Severny Island and Yuzhny Island) * Franz Josef Land (Russia) *
Svalbard Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...
(Norway, including Bear Island (Norway), Bear Island))


Ports

There are several ports and harbor, harbours on the Arctic Ocean.Arctic Ocean
. CIA World Fact Book
* Alaska ** Utqiaġvik (Barrow) ** Prudhoe Bay, Alaska, Prudhoe Bay *
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
** Manitoba: Churchill, Manitoba, Churchill (Port of Churchill) **
Nunavut Nunavut ( , ; iu, ᓄᓇᕗᑦ , ; ) is the largest and northernmost Provinces and territories of Canada#Territories, territory of Canada. It was separated officially from the Northwest Territories on April 1, 1999, via the ''Nunavut Act'' ...
: Nanisivik (Nanisivik Naval Facility) ** Tuktoyaktuk and Inuvik in the
Northwest Territories The Northwest Territories (abbreviated ''NT'' or ''NWT''; french: Territoires du Nord-Ouest, formerly ''North-Western Territory'' and ''North-West Territories'' and namely shortened as ''Northwest Territory'') is a federal territory of Canada. ...
* Greenland: Nuuk (Nuuk Port and Harbour) *
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
** Mainland: Kirkenes and Vardø **
Svalbard Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...
: Longyearbyen * Iceland ** Akureyri * Russia ** Barents Sea: Murmansk in the Barents Sea ** White Sea: Arkhangelsk ** Kara Sea: Labytnangi, Salekhard, Dudinka, Igarka and Dikson (urban-type settlement), Dikson ** Laptev Sea: Tiksi in the ** East Siberian Sea: Pevek in the East Siberian Sea


Arctic shelves

The ocean's Arctic shelf comprises a number of continental shelf, continental shelves, including the Canadian Arctic shelf, underlying the Canadian Arctic Archipelago, and the Continental shelf of Russia, Russian continental shelf, which is sometimes called the "Arctic Shelf" because it is larger. The Russian continental shelf consists of three separate, smaller shelves: the Barents Shelf, Chukchi Sea Shelf and Siberian Shelf. Of these three, the Siberian Shelf is the largest such shelf in the world; it holds large oil and gas reserves. The Chukchi shelf forms the border between Russian and the United States as stated in the USSR–USA Maritime Boundary Agreement. The whole area is subject to international Territorial claims in the Arctic, territorial claims. The Chukchi Plateau extends from the Chukchi Sea Shelf.


Underwater features

An Mid-ocean ridge, underwater ridge, the Lomonosov Ridge, divides the deep sea Arctic Basin, North Polar Basin into two oceanic basins: the Eurasian Basin, which is deep, and the Amerasian Basin (sometimes called the North American or Hyperborean Basin), which is about deep. The bathymetry of the ocean bottom is marked by fault block ridges, abyssal plains, Oceanic trench, ocean deeps, and basins. The average depth of the Arctic Ocean is . The deepest point is Molloy Hole in the Fram Strait, at about . The two major basins are further subdivided by ridges into the Canada Basin (between Beaufort Shelf of North America and the Alpha Ridge), Makarov Basin (between the Alpha and Lomonosov Ridges), Amundsen Basin (between Lomonosov and Gakkel Ridge, Gakkel ridges), and Nansen Basin (between the Gakkel Ridge and the continental shelf that includes the Franz Josef Land).


Geology

The crystalline basement rocks of mountains around the Arctic Ocean were recrystallized or formed during the Ellesmerian orogeny, the regional phase of the larger Caledonian orogeny in the Paleozoic Era. Regional subsidence in the Jurassic and Triassic periods led to significant sediment deposition, creating many of the reservoirs for current day oil and gas deposits. During the Cretaceous period, the Canadian Basin opened, and tectonic activity due to the assembly of Alaska caused hydrocarbons to migrate toward what is now Prudhoe Bay. At the same time, sediments shed off the rising Canadian Rockies built out the large Mackenzie Delta. The rifting apart of the supercontinent Pangea, beginning in the Triassic period, opened the early Atlantic Ocean. Rifting then extended northward, opening the Arctic Ocean as mafic oceanic crust material erupted out of a branch of Mid-Atlantic Ridge. The Amerasia Basin may have opened first, with the Chukchi Plateau, Chukchi Borderland moved along to the northeast by transform faults. Additional spreading helped to create the "triple-junction" of the Alpha-Mendeleev Ridge in the Late Cretaceous Epoch (geology), epoch. Throughout the Cenozoic Era, the subduction of the Pacific plate, the collision of India with Eurasia, and the continued opening of the North Atlantic created new hydrocarbon traps. The seafloor began spreading from the Gakkel Ridge in the Paleocene Epoch and the Eocene Epoch, causing the Lomonosov Ridge to move farther from land and subside. Because of sea ice and remote conditions, the geology of the Arctic Ocean is still poorly explored. The Arctic Coring Expedition drilling shed some light on the Lomonosov Ridge, which appears to be continental crust separated from the Barents-Kara Shelf in the Paleocene and then starved of sediment. It may contain up to 10 billion barrels of oil. The Gakkel Ridge rift is also poorly understand and may extend into the Laptev Sea.


Oceanography


Water flow

In large parts of the Arctic Ocean, the top layer (about ) is of lower salinity and lower temperature than the rest. It remains relatively stable because the salinity effect on density is bigger than the temperature effect. It is fed by the freshwater input of the big Siberian and Canadian rivers (Ob River, Ob, Yenisei River, Yenisei, Lena River, Lena, Mackenzie River, Mackenzie), the water of which quasi floats on the saltier, denser, deeper ocean water. Between this lower salinity layer and the bulk of the ocean lies the so-called halocline, in which both salinity and temperature rise with increasing depth. Because of its relative isolation from other oceans, the Arctic Ocean has a uniquely complex system of water flow. It resembles some hydrological features of the Mediterranean Sea, referring to its deep waters having only limited communication through the Fram Strait with the Atlantic Basin, "where the circulation is dominated by thermohaline forcing".[Regional Oceanography: An Introduction. Tomczak, Godfrey. Retrieved 18 November 2013.] The Arctic Ocean has a total volume of 18.07 × 106 km3, equal to about 1.3% of the World Ocean. Mean surface circulation is predominantly cyclonic on the Eurasian side and anticyclonic in the Canadian Basin. Water enters from both the Pacific and Atlantic Oceans and can be divided into three unique water masses. The deepest water mass is called Arctic Bottom Water and begins around depth. It is composed of the densest water in the World Ocean and has two main sources: Arctic shelf water and Greenland Sea Deep Water. Water in the shelf region that begins as inflow from the Pacific passes through the narrow Bering Strait at an average rate of 0.8 Sverdrups and reaches the
Chukchi Sea Chukchi Sea ( rus, Чуко́тское мо́ре, r=Chukotskoye more, p=tɕʊˈkotskəjə ˈmorʲɪ), sometimes referred to as the Chuuk Sea, Chukotsk Sea or the Sea of Chukotsk, is a marginal sea of the Arctic Ocean. It is bounded on the west b ...
. During the winter, cold Alaskan winds blow over the Chukchi Sea, freezing the surface water and pushing this newly formed ice out to the Pacific. The speed of the ice drift is roughly 1–4 cm/s. This process leaves dense, salty waters in the sea that sink over the continental shelf into the western Arctic Ocean and create a halocline.Arctic Ocean Circulation
. Polar Discovery
This water is met by Greenland Sea Deep Water, which forms during the passage of winter storms. As temperatures cool dramatically in the winter, ice forms, and intense vertical convection allows the water to become dense enough to sink below the warm saline water below. Arctic Bottom Water is critically important because of its outflow, which contributes to the formation of Atlantic Deep Water. The overturning of this water plays a key role in global circulation and the moderation of climate. In the depth range of is a water mass referred to as Atlantic Water. Inflow from the North Atlantic Current enters through the Fram Strait, cooling and sinking to form the deepest layer of the halocline, where it circles the Arctic Basin counter-clockwise. This is the highest volumetric inflow to the Arctic Ocean, equalling about 10 times that of the Pacific inflow, and it creates the Arctic Ocean Boundary Current. It flows slowly, at about 0.02 m/s. Atlantic Water has the same salinity as Arctic Bottom Water but is much warmer (up to ). In fact, this water mass is actually warmer than the surface water and remains submerged only due to the role of salinity in density. When water reaches the basin, it is pushed by strong winds into a large circular current called the Beaufort Gyre. Water in the Beaufort Gyre is far less saline than that of the Chukchi Sea due to inflow from large Canadian and Siberian rivers. The final defined water mass in the Arctic Ocean is called Arctic Surface Water and is found in the depth range of . The most important feature of this water mass is a section referred to as the sub-surface layer. It is a product of Atlantic water that enters through canyons and is subjected to intense mixing on the Siberian Shelf. As it is entrained, it cools and acts a heat shield for the surface layer on account of weak mixing between layers. However, over the past couple of decades a combination of the warming and the shoaling of Atlantic water are leading to the increasing influence of Atlantic water heat in melting sea ice in the eastern Arctic. The most recent estimates, for 2016–2018, indicate the oceanic heat flux to the surface has now overtaken the atmospheric flux in the eastern Eurasian Basin. Over the same period the weakening halocline stratification has coincided with increasing upper ocean currents thought to be associated with declining sea ice, indicate increasing mixing in this region. In contrast direct measurements of mixing in the western Arctic indicate the Atlantic water heat remains isolated at intermediate depths even under the 'perfect storm' conditions of the Great Arctic Cyclone of 2012. Waters originating in the Pacific and Atlantic both exit through the Fram Strait between
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
and Svalbard Island, which is about deep and wide. This outflow is about 9 Sv. The width of the Fram Strait is what allows for both inflow and outflow on the Atlantic side of the Arctic Ocean. Because of this, it is influenced by the Coriolis force, which concentrates outflow to the East Greenland Current on the western side and inflow to the Norwegian Current on the eastern side. Pacific water also exits along the west coast of Greenland and the Hudson Strait (1–2 Sv), providing nutrients to the Canadian Archipelago. As noted, the process of ice formation and movement is a key driver in Arctic Ocean circulation and the formation of water masses. With this dependence, the Arctic Ocean experiences variations due to seasonal changes in sea ice cover. Sea ice movement is the result of wind forcing, which is related to a number of meteorological conditions that the Arctic experiences throughout the year. For example, the Beaufort High—an extension of the Siberian High system—is a pressure system that drives the anticyclonic motion of the Beaufort Gyre. During the summer, this area of high pressure is pushed out closer to its Siberian and Canadian sides. In addition, there is a sea level pressure (SLP) ridge over Greenland that drives strong northerly winds through the Fram Strait, facilitating ice export. In the summer, the SLP contrast is smaller, producing weaker winds. A final example of seasonal pressure system movement is the low pressure system that exists over the Nordic and Barents Seas. It is an extension of the Icelandic Low, which creates cyclonic ocean circulation in this area. The low shifts to centre over the North Pole in the summer. These variations in the Arctic all contribute to ice drift reaching its weakest point during the summer months. There is also evidence that the drift is associated with the phase of the Arctic Oscillation and Atlantic Multidecadal Oscillation.


Sea ice

Much of the Arctic Ocean is covered by sea ice that varies in extent and thickness seasonally. The mean extent of the Arctic sea ice has been continuously decreasing in the last decades, declining at a rate of currently 12.85% per decade since 1980 from the average winter value of . The seasonal variations are about , with the maximum in April and minimum in September. The sea ice is affected by wind and ocean currents, which can move and rotate very large areas of ice. Zones of compression also arise, where the ice piles up to form pack ice. Icebergs occasionally break away from northern Ellesmere Island, and icebergs are formed from glaciers in western Greenland and extreme northeastern Canada. Icebergs are not sea ice but may become embedded in the pack ice. Icebergs pose a hazard to ships, of which the RMS Titanic, ''Titanic'' is one of the most famous. The ocean is virtually icelocked from October to June, and the superstructure of ships are subject to Icing (nautical), icing from October to May. Before the advent of modern
icebreaker An icebreaker is a special-purpose ship or boat designed to move and navigate through ice-covered waters, and provide safe waterways for other boats and ships. Although the term usually refers to ice-breaking ships, it may also refer to smaller ...
s, ships sailing the Arctic Ocean risked being trapped or crushed by sea ice (although the ''SS Baychimo, Baychimo'' drifted through the Arctic Ocean untended for decades despite these hazards).


Climate

The Arctic Ocean is contained in a polar climate characterized by persistent cold and relatively narrow annual temperature ranges. Winters are characterized by the polar night, extreme cold, frequent low-level temperature inversions, and stable weather conditions. Cyclones are only common on the Atlantic side. Summers are characterized by continuous daylight (midnight sun), and air temperatures can rise slightly above . Cyclones are more frequent in summer and may bring rain or snow. It is cloudy year-round, with mean cloud cover ranging from 60% in winter to over 80% in summer. The temperature of the surface water of the Arctic Ocean is fairly constant at approximately , near the Melting point, freezing point of seawater. The density of sea water, in contrast to fresh water, increases as it nears the freezing point and thus it tends to sink. It is generally necessary that the upper of ocean water cools to the freezing point for sea ice to form. In the winter, the relatively warm ocean water exerts a moderating influence, even when covered by ice. This is one reason why the Arctic does not experience the extreme temperatures seen on the Antarctica, Antarctic continent. There is considerable seasonal variation in how much pack ice of the Arctic ice pack covers the Arctic Ocean. Much of the Arctic ice pack is also covered in snow for about 10 months of the year. The maximum snow cover is in March or April—about over the frozen ocean. The climate of the Arctic region has varied significantly during the Earth's history. During the Paleocene–Eocene Thermal Maximum 55 million years ago, when the global climate underwent a warming of approximately , the region reached an average annual temperature of . The surface waters of the northernmost Arctic Ocean warmed, seasonally at least, enough to support tropical lifeforms (the dinoflagellates ''Apectodinium augustum'') requiring surface temperatures of over . Currently, the Arctic region is warming twice as fast as the rest of the planet.


Biology

Due to the pronounced seasonality of 2–6 months of midnight sun and polar night in the Arctic Ocean, the primary production of photosynthesizing organisms such as ice algae and phytoplankton is limited to the spring and summer months (March/April to September). Important consumers of primary producers in the central Arctic Ocean and the adjacent Continental shelf, shelf seas include zooplankton, especially copepods (''Calanus finmarchicus'', ''Calanus glacialis'', and ''Calanus hyperboreus'') and Krill, euphausiids, as well as ice-associated fauna (e.g., Amphipoda, amphipods). These primary consumers form an important link between the primary producers and higher trophic levels. The composition of higher trophic levels in the Arctic Ocean varies with region (Atlantic side vs. Pacific side) and with the sea-ice cover. Secondary consumers in the
Barents Sea The Barents Sea ( , also ; no, Barentshavet, ; russian: Баренцево море, Barentsevo More) is a marginal sea of the Arctic Ocean, located off the northern coasts of Norway and Russia and divided between Norwegian and Russian territo ...
, an Atlantic-influenced Arctic shelf sea, are mainly sub-Arctic species including herring, young Atlantic cod, cod, and capelin. In ice-covered regions of the central Arctic Ocean, Boreogadus saida, polar cod is a central predator of primary consumers. The apex predators in the Arctic Ocean—marine mammals such as Pinniped, seals, whales, and polar bears—prey upon fish. Endangered marine species in the Arctic Ocean include walruses and whales. The area has a fragile ecosystem, and it is especially exposed to Global warming, climate change, because it warms faster than the rest of the world. Lion's mane jellyfish are abundant in the waters of the Arctic, and the banded gunnel is the only species of Pholidae, gunnel that lives in the ocean.


Natural resources

Petroleum and natural gas Natural gas field, fields, placer deposits, Manganese nodule, polymetallic nodules, sand and gravel Construction aggregate, aggregates, fish, seals and whales can all be found in abundance in the region. The political dead zone near the centre of the sea is also the focus of a mounting dispute between the United States, Russia, Canada, Norway, and Denmark. It is significant for the global energy market because it may hold 25% or more of the world's undiscovered oil and gas resources.


Environmental concerns


Arctic ice melting

The Arctic ice pack is thinning, and a seasonal hole in the ozone layer frequently occurs. Reduction of the area of Arctic sea ice reduces the planet's average albedo, possibly resulting in global warming in a positive feedback mechanism.Earth – melting in the heat?
Richard Black, 7 October 2005. BBC News. Retrieved 7 December 2006.
Research shows that the Arctic may become ice-free in the summer for the first time in human history by 2040. Estimates vary for when the last time the Arctic was ice-free: 65 million years ago when fossils indicate that plants existed there to as recently as 5,500 years ago; ice and ocean cores going back 8,000 years to the Holocene thermal maximum, last warm period or 125,000 during the Eemian, last intraglacial period. Warming temperatures in the Arctic may cause large amounts of fresh meltwater, melt-water to enter the north Atlantic, possibly disrupting global thermohaline circulation, ocean current patterns. Potentially severe changes in the Earth's climate might then ensue. As the extent of sea ice diminishes and sea level rises, the effect of storms such as the Great Arctic Cyclone of 2012 on open water increases, as does possible salt-water damage to vegetation on shore at locations such as the Mackenzie river delta, Delta as stronger storm surges become more likely. Global warming has increased encounters between polar bears and humans. Reduced sea ice due to melting is causing polar bears to search for new sources of food. Beginning in December 2018 and coming to an apex in February 2019, 2019 mass invasion of Russian polar bears, a mass invasion of polar bears into the archipelago of
Novaya Zemlya Novaya Zemlya (, also , ; rus, Но́вая Земля́, p=ˈnovəjə zʲɪmˈlʲa, ) is an archipelago in northern Russia. It is situated in the Arctic Ocean, in the extreme northeast of Europe, with Cape Flissingsky, on the northern island, ...
caused local authorities to declare a state of emergency. Dozens of polar bears were seen entering homes, public buildings and inhabited areas.


Clathrate breakdown

Sea ice, and the cold conditions it sustains, serves to stabilize methane deposits on and near the shoreline, preventing the clathrate breaking down and outgassing methane into the atmosphere, causing further warming. Melting of this ice may release large quantities of methane, a powerful greenhouse gas, into the atmosphere, causing further warming in a strong positive feedback cycle and marine genera and species to become extinct.


Other concerns

Other Environmentalism, environmental concerns relate to the radioactive contamination of the Arctic Ocean from, for example, Russian radioactive waste dump sites in the Kara Sea, Cold War Nuclear weapons testing, nuclear test sites such as Novaya Zemlya, Camp Century's contaminants in Greenland, and radioactive contamination from the Fukushima Daiichi nuclear disaster. On 16 July 2015, five nations (United States, Russia, Canada, Norway, Denmark/Greenland) signed a declaration committing to keep their fishing vessels out of a 1.1 million square mile zone in the central Arctic Ocean near the North Pole. The agreement calls for those nations to refrain from fishing there until there is better scientific knowledge about the marine resources and until a regulatory system is in place to protect those resources.


See also

* Arctic Bridge * Arctic cooperation and politics * Extreme points of the Arctic * International Arctic Science Committee * List of rivers of the Americas by coastline * Nordicity * Seven Seas * Subarctic


References


Further reading

* Neatby, Leslie H., ''Discovery in Russian and Siberian Waters'' (1973), . * Ray, L., and B. Bacon, eds., ''The Arctic Ocean'' (1982), . * Thorén, Ragnar V.A., ''Picture Atlas of the Arctic'' (1969), .


External links


Arctic Council

Arctic Environmental Atlas
Interactive map
Arctic Great Rivers Observatory (ArcticGRO)

Arctic Ocean
''The World Factbook''. Central Intelligence Agency.
Daily Arctic Ocean Rawinsonde Data from Soviet Drifting Ice Stations (1954–1990)
at NSIDC

Images from Web Cams deployed in spring on an ice floe

Data from instruments deployed on an ice floe
International Polar Foundation
* {{Authority control Islands of the Arctic Ocean, several islands Arctic Ocean, Oceans Extreme points of Earth Landforms of the Arctic Ocean, Articles containing video clips Geography of Northeast Asia Geography of Northern Europe Geography of Eastern Europe Geography of North America Seas of the United States Seas of Canada Seas of Greenland Seas of Norway Seas of Russia