The Arctic Ocean
The Arctic Ocean is the smallest and shallowest of Earth's five oceans. It sits at the very top of the world, ringed by Russia, Canada, Alaska, Greenland and northern Europe. Much of its surface is covered by floating sea ice all year round, though the ice has been shrinking quickly because of climate change. The Arctic Ocean is home to polar bears, narwhals, walruses and some of the loneliest islands on Earth.
- Surface area15.6 million km²Smallest of the five oceans
- Average depth1,205 mShallowest of the major oceans
- Deepest pointMolloy Holeapprox. 5,550 m, north of Norway
- Frozen surfaceMost of the yearSea ice cover changes with the seasons
- Coldest tempAround -2 °CSalt water freezes at about -2°C
- Famous animalPolar bearThe biggest land carnivore on Earth
How small is the Arctic Ocean?
Area in millions of km².
The Arctic is barely a tenth the size of the Pacific. It is also unusual because so much of its surface is frozen most of the year.
What is the Arctic Ocean?
The Arctic Ocean is the small, cold sea at the top of our planet, surrounding the North Pole. It is almost completely surrounded by land: Russia, Canada, Alaska (which is part of the United States), Greenland and the northern coasts of Norway and Iceland. The word "Arctic" comes from the Greek "arktos", meaning "bear", a reference to the constellation Ursa Major (the Great Bear) which sits over the northern sky.
Sea ice
Most of the Arctic Ocean is covered by floating sea ice for at least part of every year. The amount of ice grows in winter (when temperatures can drop to -40 °C) and shrinks in summer. The thickest ice, called multi-year ice, never melts. As the climate warms, however, more ice melts each summer than freezes back the following winter. The Arctic is now warming roughly four times faster than the rest of the planet.
The shrinking ice is bad news for polar bears, walruses and other Arctic animals that hunt on the ice. But it has also opened up new shipping routes through the Northwest Passage (across the top of Canada) and the Northeast Passage (across the top of Russia), which used to be ice-blocked most of the year.
Wildlife of the Arctic Ocean
The Arctic looks empty but is teeming with life. Polar bears live on the sea ice and hunt seals from it. Walruses use their long tusks to haul themselves out onto ice floes. Narwhals, the "unicorns of the sea", have a long spiral tusk that is actually a tooth. Beluga whales are friendly white whales nicknamed "sea canaries" for their songs. Beneath the ice live tiny shrimp-like creatures called krill that feed almost the entire food chain.
Explorers and the Arctic
Reaching the North Pole was one of the great quests of the 19th and 20th centuries. Many expeditions failed and many explorers died. The American explorers Robert Peary and Frederick Cook both claimed to have reached the Pole in 1908 and 1909, but neither claim is now widely accepted. The first verified surface expedition to the North Pole was led by British explorer Wally Herbert in 1969. The first ship to reach the Pole, the Soviet nuclear-powered icebreaker Arktika, did so in 1977.
Deeper dive: Arctic amplification, sea-ice albedo and the Northwest Passage
The Arctic is warming faster than anywhere else on Earth in a process called Arctic amplification. The main reason is the loss of sea ice. Ice is white and reflects most of the sunlight that hits it back to space. When it melts, it exposes dark blue ocean water, which absorbs most of the sunlight instead. The extra heat then melts more ice, exposing more dark water, in a self-reinforcing feedback loop. Satellite records since 1979 show Arctic summer sea-ice extent has shrunk by roughly 40% and the volume of ice has shrunk even more, since the remaining ice is thinner.
The albedo effect (the difference in reflectivity between ice and water) is one of the most powerful climate feedbacks on Earth. It is part of why climate models predict the Arctic Ocean will be essentially ice-free in summer (less than one million square km of ice) somewhere between the 2030s and 2050s.
The shrinking ice has reopened the legendary Northwest Passage across the top of Canada and the Northern Sea Route across the top of Russia. The Northwest Passage was the goal of countless 19th-century expeditions, including the doomed 1845 Franklin expedition (whose ships were finally located in 2014 and 2016). Successfully transiting the passage now happens regularly, although only during the short summer season. The opening of these routes also raises difficult questions about national jurisdictions, shipping safety, oil and gas exploration, and the rights of Arctic indigenous peoples like the Inuit, who have inhabited the region for thousands of years.
The other polar ocean is the Southern Ocean around Antarctica. The biggest ocean is the Pacific. The most historically important is the Atlantic.