Arctic Ocean quick facts
- The Arctic is the smallest and shallowest of the world’s five oceans.
- Its average depth is about 1,205 metres (3,953 feet).
- It is almost completely covered with ice for most of the year.
- The record low for summer sea ice was 3.39 million square kilometres, in 2012.
- The Arctic is warming up to four times faster than the planet as a whole.
There is no land at the North Pole. The pole sits in the middle of the Arctic Ocean, usually covered by a crust of floating sea ice.
Where the Arctic Ocean is
The Arctic Ocean wraps around the top of the world. It is bordered by Greenland, Canada, Norway, Alaska and Russia.
It is about one and a half times the size of the United States. That sounds huge, but it is still the smallest of the world’s five oceans.
The Arctic is an ocean surrounded by land. Antarctica, at the other end of the Earth, is the opposite: land surrounded by ocean.
The smallest and shallowest ocean
| Measure | Arctic Ocean |
|---|---|
| Area | About 15.8 million square kilometres (6.1 million square miles) |
| Average depth | About 1,205 metres (3,953 feet) |
| Deepest point | About 5,567 metres (18,264 feet) |
| Ice cover | Almost completely covered for most of the year |
| Temperature | Seldom rises above freezing |
Its average depth of about 1,205 metres makes it the shallowest ocean too. Much of its floor is wide, shallow shelf around the coasts.
Six months of day, six months of night
At the North Pole, the year has one very long day and one very long night. The sun comes up in March and does not set again until September. Then it sinks below the horizon and stays hidden until the next spring.
This happens because the Earth is tilted. Its axis leans over by about 23.4 degrees. For half of each trip around the sun, the top of the world leans towards the sun and gets light all the time. For the other half, it leans away and stays dark.
The two halves are not quite equal. At the North Pole itself, the polar day lasts about 186 days and the polar night about 179. The day wins by about a week, partly because the Earth travels a little more slowly around the sun during the northern summer.
Further south, the midnight sun is shorter. On the Arctic Circle, the sun stays up for just one full day around the summer solstice in June. Only about 100 km closer to the pole, it stays up for several weeks.
Sea ice that grows and shrinks
Arctic sea ice is frozen seawater. It grows through the dark winter and shrinks through the summer. Each year it reaches its smallest size in September.
Satellites have measured it since the late 1970s. In 2012, the summer ice shrank to just 3.39 million square kilometres. That is still the lowest on record.
In 2025, the ice reached its smallest size on 10 September, at 4.60 million square kilometres. That tied with 2008 and 2010 as the tenth lowest ever measured.
Here is the fact that matters most. The 19 lowest summers on record have all come in the last 19 years. Over the whole record, the summer ice has shrunk by about 12% every ten years.
Why the Arctic is changing
The Arctic is warming up to four times faster than the planet as a whole. Less ice means more dark ocean soaking up the sun’s heat.
Every year, the United States science agency NOAA publishes an Arctic Report Card. The 2025 edition, its twentieth, picked out three big changes:
- Atlantification. Warmer, saltier water from the Atlantic is pushing further north into the Arctic.
- New neighbours. Plants and animals from further south are spreading into Arctic ecosystems.
- Rusting rivers. As frozen ground thaws, iron and other metals wash into rivers and turn them rust-coloured.
Life on the ice
The sea ice is a hunting ground as well as a lid on the ocean. Polar bears travel across it in search of seals. Along the coasts and on the ice live Arctic foxes, also called the polar fox.
Their main prey is the ringed seal, with bearded seals second. When they get the chance, they also eat walruses, belugas and the remains of dead whales.
The polar bear is the biggest kind of bear alive today. In 2023, about 26,000 of them were thought to live in the Arctic, split into 19 separate groups across Canada, Greenland, Norway, Russia and the United States.
When the ice melts earlier and forms later, these animals have less time and less space to hunt.
Whales of the Arctic
The narwhal is often called the unicorn of the sea, because of the long, spiral tusk on its head. The tusk is actually a tooth. It grows out through the front of the jaw, twists to the left, and can reach about 3 metres (9.8 feet) long and weigh more than 9 kg (20 pounds). Mostly, it is the males that have one.
Male narwhals can grow up to 4.8 metres (15.7 feet) long and weigh about 1,600 kg. They are champion divers, going as deep as 1,200 metres and staying under for up to 25 minutes. Down there they hunt Arctic cod, polar cod, turbot, squid and shrimp.
Narwhals live in the Arctic Ocean, from central Canada to Greenland and eastern Russia. Climate change, loss of sea ice and hunting are among the threats they face.
The beluga is the white whale. It makes so many sounds, whistles, squeals, moos, chirps and clicks, that it has earned the nickname canary of the sea.
On top of its head is a soft, round bump called the melon. The beluga can change its shape to aim and adjust its sounds. It uses clicks to find its way and its food, a skill called echolocation.
Belugas are not born white. Calves are dark grey, and their skin gets paler as they grow, until it turns white when they are adults. A grown beluga can be up to about 4.9 metres (16 feet) long.
One group, the belugas of Cook Inlet in Alaska, is endangered. There were about 1,300 of them in 1979. Today there are only about 331.
People of the Arctic
The Arctic is not empty. Almost four million people live there, according to the Arctic Council, where Arctic countries and Indigenous peoples work together.
Roughly one in ten of them are Indigenous, about half a million people. They include the Inuit, the Saami, the Aleut, the Gwich’in, Athabaskan peoples and the Indigenous peoples of northern Russia. Some hunt and herd on the land. Others live in towns and cities.
Reaching the North Pole
Because there is no land at the North Pole, getting there is hard. There is nothing solid to stand on, only sea ice that cracks and moves.
The first undisputed journey across the ice to the pole ended at 3 p.m. on 19 April 1968. The American Ralph Plaisted got there with three teammates, Walter Pederson, Gerald Pitzl and the Canadian Jean-Luc Bombardier. They travelled by snowmobile, and the trek took 42 days.
Ten years earlier, a submarine had gone underneath. On 3 August 1958, USS Nautilus, a nuclear-powered submarine of the United States Navy, became the first submarine to reach the North Pole, passing beneath the ice.
When it came back to the surface, its commander, William Anderson, sent a three-word message: “Nautilus 90 North”. The North Pole sits at 90 degrees north, the very top of the map. Today Nautilus is a historic ship in Groton, Connecticut.
Three things people get wrong
There is no land at the North Pole. It lies in the middle of the Arctic Ocean, on floating sea ice.
The Arctic and Antarctica are not mirror images. The Arctic is an ocean ringed by land. Antarctica is a continent ringed by ocean.
One better year does not mean the ice is recovering. 2025 was only the tenth lowest. But the 19 lowest years are still all among the last 19.
Did you know? Scientists now describe some Arctic rivers as rusting. As frozen ground thaws, iron and other metals wash out of the soil and turn the water rust-coloured.
Try it
Look down on a globe from the top. Trace the edge of the Arctic Ocean with your finger and name the five places that border it: Greenland, Canada, Norway, Alaska and Russia.
Knowledge check
Which is the smallest of the world’s five oceans?
Show answer
The Arctic Ocean. It is also the shallowest, with an average depth of about 1,205 metres.
In which month does Arctic sea ice usually reach its smallest size?
Show answer
September, at the end of the summer melt. In 2025 it reached its minimum on 10 September.
Frequently asked questions
How big is the Arctic Ocean?
The Arctic Ocean covers about 6.1 million square miles, roughly 15.8 million square kilometres, or about one and a half times the size of the United States. It is the smallest of the world’s five oceans.
How deep is the Arctic Ocean?
The Arctic Ocean has an average depth of about 1,205 metres (3,953 feet), which makes it the shallowest ocean. Its deepest point is about 5,567 metres (18,264 feet).
Which countries border the Arctic Ocean?
The Arctic Ocean is bordered by Greenland, Canada, Norway, Alaska in the United States, and Russia.
Is Arctic sea ice shrinking?
Yes. Arctic summer sea ice has shrunk by about 12% per decade since satellite records began in 1979, and the 19 lowest summer minimums have all happened in the last 19 years.
What was the lowest Arctic sea ice on record?
The lowest Arctic sea ice minimum on record was 3.39 million square kilometres, in September 2012. The 2025 minimum, 4.60 million square kilometres, tied for tenth lowest.
How fast is the Arctic warming?
The Arctic is warming up to four times faster than the global average, according to the US National Snow and Ice Data Center. That warming is shrinking sea ice and thawing frozen ground.
Does the sun set at the North Pole?
Only once a year. At the North Pole the sun rises in March and does not set until September, giving about 186 days of daylight. Then it stays below the horizon for about 179 days of polar night. This happens because the Earth’s axis is tilted by about 23.4 degrees.
What whales live in the Arctic?
The narwhal and the beluga live in the Arctic all year. The narwhal’s tusk is a tooth that can grow to about 3 metres, and the beluga is a white whale nicknamed the canary of the sea for its many sounds.
Who first reached the North Pole?
The first undisputed journey over the ice was made by Ralph Plaisted’s team on snowmobiles, arriving on 19 April 1968 after a 42-day trek. Ten years earlier, on 3 August 1958, the submarine USS Nautilus passed beneath the pole under the ice.
How many people live in the Arctic?
Almost four million people live in the Arctic. Roughly one in ten are Indigenous, including the Inuit, Saami, Aleut and Gwich’in peoples.
What do polar bears eat?
Polar bears mainly hunt ringed seals, and to a lesser extent bearded seals. They also eat walruses, belugas and the remains of dead whales when they can.
Sources
- NOAA Ocean Service: what is the world’s smallest ocean? — the Arctic Ocean’s area, depth, borders and ice cover
- National Snow and Ice Data Center: the 2025 Arctic sea ice minimum — the 2025 minimum, the 2012 record and the long-term trend
- National Snow and Ice Data Center: sea ice today — how fast the Arctic is warming compared with the planet
- NOAA Arctic Report Card 2025 — Atlantification, species moving north and rusting rivers
- Wikipedia: midnight sun — the length of polar day and night at the North Pole, and the Earth’s tilt
- US Fish and Wildlife Service: polar bear — what polar bears eat, their numbers and where they live
- NOAA Fisheries: narwhal — the narwhal’s tusk, size, diving, food, range and threats
- NOAA Fisheries: beluga whale — beluga sounds, the melon, colour, size and the Cook Inlet population
- Arctic Council: Arctic peoples — how many people live in the Arctic and the share who are Indigenous
- Guinness World Records: first undisputed surface journey to the North Pole — Ralph Plaisted’s 1968 snowmobile expedition
- Connecticut Office of Military Affairs: Nautilus 90 North — USS Nautilus reaching the North Pole in 1958
