The Arctic and Antarctic Compared: Facts About the Polar Regions

The Arctic and Antarctica are both cold, remote and icy, so people often treat them as similar. In fact, they are very different places, and understanding the contrast clears up many common mix-ups.

Key takeaways

• The Arctic is an ocean surrounded by land, while Antarctica is a continent surrounded by an ocean.
• Antarctica holds about 90 percent of the world's ice and is the coldest place on Earth.
• Polar bears live in the Arctic and penguins live in the south.
• People have lived in the Arctic for thousands of years, but Antarctica has no native population.
• Antarctica is governed by an international treaty devoted to peace and science.

Geography

The Arctic is centred on the North Pole in the Arctic Ocean, which is largely covered by floating sea ice that expands in winter and shrinks in summer. It is surrounded by the northern parts of North America, Europe and Asia, as well as Greenland. Antarctica is a continent around the South Pole, covered by an ice sheet that is on average more than two kilometres thick, with some areas much thicker.

Temperature

Antarctica is the coldest, driest and windiest continent. The lowest temperature ever recorded at ground level on Earth, minus 89.2 degrees Celsius, was measured at Vostok Station in Antarctica in 1983. Because the continent is high on average and far from the moderating influence of oceans, it is colder than the Arctic. Arctic winter temperatures in many places can still fall below minus 40 degrees Celsius.

Ice

Antarctica's ice sheet contains about 90 percent of the planet's ice and, if it melted entirely, would raise global sea level by around 58 metres, a scenario not expected on human timescales. The Arctic's sea ice floats, so its melting does not add much to sea level, though the Greenland ice sheet, which is on land, does.

Wildlife

Polar bears, Arctic foxes, reindeer or caribou, walruses, musk oxen, snowy owls and narwhals live in or around the Arctic. In Antarctica, there are several species of penguins, seals, seabirds and a rich community of marine life, including krill that feed whales. The land has very few native land animals, mostly small invertebrates such as mites and springtails. Penguins live only in the Southern Hemisphere, and polar bears only in the Arctic, so they never meet in the wild.

People

Indigenous peoples, including the Inuit, Sámi, Nenets and many others, have lived in the Arctic for thousands of years. Antarctica has no permanent residents. Several thousand scientists and support staff live at research stations during the summer, and fewer remain through the winter.

Governance

The Arctic is governed by the laws of the eight countries with territory there, supported by cooperation through bodies such as the Arctic Council. Antarctica is covered by the Antarctic Treaty of 1959, which reserves the continent for peaceful purposes and scientific research, and bans military activity and new territorial claims while the treaty is in force. Mining is prohibited under a later environmental protocol.

Midnight sun and polar night

Both regions have long periods of continuous daylight in summer and continuous darkness in winter because of Earth's tilt, but they occur at opposite times of year. When it is summer in the Arctic, it is winter in Antarctica.

Climate change

Both polar regions are changing. The Arctic has warmed faster than the global average, and summer sea ice has declined. Antarctica's response is more varied, with some regions warming and losing ice, while others show less change. Scientists use satellites and field measurements to monitor them.

Sea ice and why it matters

Sea ice is frozen seawater that floats on the ocean. In the Arctic it expands each winter to cover millions of square kilometres and shrinks to its minimum in September. Bright ice reflects most sunlight back to space, while dark open water absorbs it, so losing ice means more heat is taken up, which can speed warming. This is one reason the Arctic is warming faster than the global average, a pattern called Arctic amplification. Satellite records since 1979 show that summer Arctic sea ice has declined substantially.

East and West Antarctica

The Antarctic ice sheet is divided by the Transantarctic Mountains. East Antarctica is larger, thicker and sits mostly on high ground. West Antarctica rests on land that lies below sea level in many places, which makes it more vulnerable to warm ocean water reaching beneath the ice. Floating ice shelves, such as Ross and Ronne-Filchner, act as buttresses that slow the flow of ice from land into the sea, and the loss of some shelves has been observed to speed up glaciers behind them. How fast the ice sheets will change is one of the major uncertainties in forecasts of sea-level rise.

How animals survive the cold

Polar animals have many adaptations. Polar bears have thick fur and a layer of fat, and their black skin helps absorb heat. Seals and whales use blubber to insulate against cold water. Birds and mammals have countercurrent heat exchange in their limbs, where warm blood leaving the body warms the cooler blood coming back, reducing heat loss. At the base of the Antarctic food web is krill, small crustaceans that feed on algae growing under and around ice, and that in turn feed whales, seals and penguins.

Exploration and science

Exploration of both poles was dangerous. Roald Amundsen's Norwegian team reached the South Pole in December 1911, and Robert Falcon Scott's British team arrived about a month later and died on the return journey. Claims about who first reached the North Pole are disputed. Today scientists work at research stations. Ice cores, long cylinders drilled from the ice sheets, contain trapped air bubbles that record past atmospheres, and cores from Antarctica have given a climate record stretching back about 800,000 years.

Protecting the poles

The Antarctic Treaty System includes the Madrid Protocol of 1991, which bans mining and sets strict environmental rules. A separate commission regulates fishing in the Southern Ocean, including for krill. In the Arctic, countries cooperate through the Arctic Council on environment and sustainable development, although it does not govern the region directly. Tourism is growing at both poles, and visitors are expected to follow guidelines that protect wildlife and sites.

Frequently asked questions

Which pole is colder?

The South Pole, because it is on a high ice-covered continent.

Can you walk to the North Pole?

Expeditions have done so, but the Arctic Ocean ice is moving and thinning, which makes it risky.

Does anyone own Antarctica?

Several countries have historic claims, but the Antarctic Treaty sets them aside.

Is the ozone hole at the poles?

The ozone hole, a thinning of the ozone layer, appears over Antarctica each spring. It was caused mainly by chemicals called CFCs, which were phased out under the Montreal Protocol. The ozone layer is slowly recovering, and a return to earlier levels is expected around the middle of this century.

Why is the Arctic warming faster than the rest of the world?

Several processes combine. Melting ice exposes darker water that absorbs more sunlight, and changes in clouds, ocean heat and atmospheric circulation also contribute. This extra warming is known as Arctic amplification.

Can tourists visit Antarctica?

Yes. Tens of thousands of people visit each year, mostly on ship cruises in the Antarctic summer. Operators must follow rules designed to protect the environment, such as limits on the number of people landing at one time.

Sources and further reading

• Antarctica (Wikipedia)
• National Snow and Ice Data Center