Arctic Tundra Biome
The Arctic Tundra is the coldest, windiest and most barren biome on Earth — a vast, frozen plain that rings the top of the world like a crown of ice. There are no trees, winters last nine months, and temperatures have been recorded as low as −70°C. Yet this seemingly hostile landscape is alive: polar bears, Arctic foxes, musk oxen and millions of migrating birds all call it home, and beneath the frozen soil lies one of the planet's most important carbon stores.
- Area Coveredapprox. 8 million km²About the size of Brazil
- LocationArctic CircleNorthern Canada, Alaska, Russia, Scandinavia, Greenland
- Annual Rainfall200–500 mmMostly snow; one of Earth's driest biomes
- Temperature−70°C to +12°CAverage annual temperature −28°C
- Growing Seasonapprox. 10 weeksThe shortest of any biome
- PermafrostUp to 450 m deepPermanently frozen ground underlies the whole biome
How does the Arctic Tundra compare to other biomes by rainfall?
The tundra is almost as dry as a desert — yet it stays waterlogged because permafrost stops water draining away.
Despite its low rainfall, the Arctic Tundra is not dry underfoot — the permafrost acts like a bathtub, trapping meltwater at the surface each summer and creating thousands of lakes, ponds and boggy areas that teem with insects and waterbirds.
What is the Arctic Tundra?
The word tundra comes from the Finnish tuntura, meaning a treeless plain. The Arctic Tundra is defined by three things that set it apart from every other biome: permafrost, extremely low temperatures, and an almost total absence of trees. Permafrost — ground that stays permanently frozen year-round — lies beneath the entire biome, preventing tree roots from reaching deep into the soil and stopping meltwater from draining away. In summer, only the top metre or so thaws, creating the shallow "active layer" where all of the tundra's life happens.
The Arctic Tundra is one of two tundra types — the other being Alpine Tundra, found above the treeline on mountains worldwide. The Arctic variety encircles the North Pole, forming a band between the polar ice cap and the boreal forests of the taiga. It covers roughly eight million square kilometres across northern Canada, Alaska, Greenland, Scandinavia and Siberia — approx. 20% of Earth's total land surface.
Where is the Arctic Tundra found?
The Arctic Tundra forms a near-continuous ring around the North Pole, immediately south of the permanent polar ice cap and north of the taiga forest belt. Major tundra regions include the North Slope of Alaska, the Canadian Arctic Archipelago, most of Greenland (outside the ice sheet), Svalbard and northern Scandinavia, and the vast Siberian plains of Russia — by far the largest single tundra landmass on Earth. Russia alone contains about half of all the world's tundra. The southernmost tundra patches reach into the Hudson Bay lowlands of Canada at around 55°N — further south than London.
Climate and seasons
The Arctic Tundra has just two seasons: a long, brutal winter and a brief, cool summer. Winter lasts roughly nine months, with temperatures plunging to −40°C to −70°C and winds reaching 30–60 mph, creating a wind chill that makes exposure to the open air genuinely lethal. For months around the winter solstice, the sun never rises at all — the Arctic experiences total polar night. Summer arrives abruptly in June, bringing almost continuous daylight (the midnight sun) and temperatures that briefly reach 3–12°C. This warmth is enough to melt the active layer and allow a burst of plant growth, flowering and animal activity before winter returns in September.
Annual precipitation is very low — 200–500 mm, comparable to many deserts — but because the permafrost prevents drainage, the landscape is surprisingly waterlogged in summer, dotted with lakes, ponds and boggy depressions. The freeze-thaw cycle causes the soil to heave and crack, creating the remarkable geometric patterns of frost polygons visible across the tundra from the air.
Plants of the Arctic Tundra
About 1,700 plant species have adapted to life on the Arctic Tundra — a remarkable number given the conditions. With such a short growing season and freezing temperatures, all tundra plants grow low to the ground, huddling together to conserve warmth and avoid the scouring wind. Arctic mosses and lichens are the foundation of the ecosystem, covering vast areas of rock and soil and providing food for caribou and musk oxen. Sedges and cotton grasses grow in wetter areas. Dwarf willows and dwarf birches creep along the ground, their trunks sometimes just centimetres tall despite being decades old. In summer, the tundra bursts into colour with hundreds of species of flowering plants — Arctic poppies, saxifrages, purple saxifrage and mountain avens — that must germinate, flower and set seed within the brief summer window.
Animals of the Arctic Tundra
The Arctic Tundra supports a surprisingly rich animal community, all of which have evolved remarkable adaptations to the cold. The polar bear — the apex predator of the Arctic — has a thick layer of insulating blubber, a dense fur coat, and large, slightly webbed feet for swimming and walking on ice. Caribou (reindeer) migrate in herds of hundreds of thousands across the tundra, following the retreating snow to reach new grazing each spring. Musk oxen, one of the few large mammals that stay on the tundra year-round, huddle in defensive circles when threatened and have underwool so fine it is warmer than cashmere. Arctic foxes follow polar bears to scavenge scraps and have the warmest fur of any mammal relative to their size. Lemmings — small rodents that live year-round under the snow — drive three- to four-year population cycles that cascade through the entire tundra food web, affecting predators from snowy owls to Arctic foxes.
In summer, the tundra receives millions of migratory birds from around the world, drawn by the long daylight hours and prolific insect life. Geese, ducks, waders, skuas and the long-distance champion Arctic tern — which migrates from pole to pole each year — all breed on the tundra.
Arctic Tundra food web
The Arctic Tundra food web is relatively simple compared to warmer biomes — the extreme cold and short growing season limit the number of species and the complexity of relationships between them. At its base are the producers: mosses, lichens, sedges, grasses and dwarf shrubs that capture energy from the brief summer sun. Herbivores including caribou, musk oxen, lemmings and Arctic hares feed on these plants. Carnivores including Arctic foxes, snowy owls, rough-legged hawks and wolves hunt the herbivores. The polar bear sits at the top of the marine-tundra food web, hunting seals on the sea ice; seals feed on fish, which feed on krill and smaller invertebrates, which in turn feed on algae. The Arctic wolf preys on caribou and musk oxen. Lemmings — tiny rodents that live under the snow year-round — are a keystone species: in years when lemmings are abundant, snowy owls, Arctic foxes and long-tailed skuas all breed successfully; when lemming populations crash, predator numbers follow. Decomposers — bacteria and fungi — process dead material very slowly in the cold, which is why organic carbon accumulates as peat rather than being released back to the atmosphere quickly.
How animals adapt to the Arctic Tundra
Surviving the Arctic requires extraordinary physiological and behavioural adaptations. The polar bear has hollow, transparent guard hairs that channel solar radiation to dark skin beneath; a 10 cm thick layer of blubber; and large, partially webbed feet that act as snowshoes and paddles. Its white fur provides both camouflage in snow and thermal insulation. Caribou have broad, flat hooves that act as shovels to dig through snow for lichens, and also as paddles when swimming. Their noses pre-warm cold air before it reaches the lungs. Musk oxen grow two layers of fur — a coarse outer layer that sheds water and snow, and an inner layer of qiviut (an insulating wool eight times warmer than sheep's wool). They huddle in defensive circles facing outward when threatened by wolves, calves at the centre. The Arctic fox changes coat twice a year: white in winter for snow camouflage, brown-grey in summer to match the tundra ground. Its very small ears, short muzzle and compact body minimise heat loss. Lemmings do not hibernate — they tunnel beneath the snow where temperatures stay around −5°C even when the surface reaches −40°C, feeding on roots and grass they can access through the insulating snow layer.
Threats and conservation
The Arctic Tundra is warming at nearly four times the global average rate — a phenomenon called Arctic amplification. This is thawing the permafrost, releasing ancient stores of carbon, causing coastal erosion as frozen ground melts into the sea, and fundamentally changing the ecosystem. Shrubs are expanding northwards into areas previously too cold for them (a process called "shrubification"), reducing the reflective white ground cover and causing the tundra to absorb more solar heat. Polar bears, whose hunting depends on sea ice, are losing their habitat rapidly. Oil and gas development in the Arctic has created roads, pipelines and drilling infrastructure that fragment habitat and pollute waterways. Despite its remoteness, the Arctic Tundra is one of the most rapidly changing ecosystems on Earth.
Deeper dive: permafrost, carbon feedback and the future of the tundra
Permafrost is not simply frozen soil — it is a vast, ancient archive of organic material: the partially decomposed remains of plants, animals and microbes that lived over the past 10,000 to 40,000 years, preserved by cold before they could fully decay. As long as the ground stays frozen, this carbon stays locked away. But as the permafrost thaws, bacteria begin decomposing the material, releasing carbon dioxide and methane. Methane is 80 times more potent than CO₂ as a greenhouse gas over a 20-year period.
Scientists estimate that the Arctic permafrost holds approx. 1.7 trillion tonnes of carbon — roughly double what is currently in the atmosphere. Even releasing a small fraction of this could significantly accelerate global warming. Already, some Arctic lakes are bubbling with methane released from thawing permafrost beneath them. The permafrost carbon feedback is one of the largest potential tipping points in the Earth's climate system, which is why Arctic temperatures are so closely watched by climate scientists worldwide.
The Arctic Tundra is one of the world's last great wildernesses — vast, fragile, and changing faster than almost any other ecosystem. The closely related Tundra Biome page explores both the Arctic and Alpine tundra types in more detail.