The cold, treeless land
The word tundra comes from the Sami word tūndâr, meaning "treeless plain." The tundra is one of the coldest and harshest biomes on Earth. It covers about one-tenth of Earth’s land and about one-quarter of Canada.
Two kinds of tundra
| Arctic tundra | Alpine tundra | |
|---|---|---|
| Where | Far north: northern Canada, Alaska, Russia, Greenland, Scandinavia | High on mountains above the treeline, anywhere in the world |
| Permafrost | Yes | Usually no |
| Canadian examples | Nunavut, northern Yukon, NWT, Nunavik, northern Labrador | The Rocky Mountains above about 2000–2500 m |
Climate
| Feature | Arctic tundra |
|---|---|
| Winter temperature | Often −30 °C or colder |
| Summer temperature | About 3–12 °C |
| Growing season | Only 50–60 days |
| Precipitation | About 150–250 mm per year, as little as some deserts |
| Wind | Often very strong |
In winter, the Sun may not rise for weeks. In summer, it may not set, giving 24-hour daylight, the "midnight sun."
Permafrost
Permafrost is ground that stays frozen for at least two years in a row. In parts of the Arctic, it reaches hundreds of metres deep.
Each summer, only the top layer, called the active layer, thaws. Because water can’t drain into the frozen ground below, the surface becomes boggy, with many ponds and marshes. Permafrost also prevents deep roots, which is one reason trees can’t grow.
Plants
About 1700 kinds of plants grow in the Arctic tundra. They’re small and tough.
| Plant | Adaptation |
|---|---|
| Mosses and lichens | Grow on bare rock; survive freezing and drying; lichens are an important food for caribou |
| Arctic willow | Grows only a few centimetres tall, spreading along the ground out of the wind |
| Cotton grass | Fluffy seed heads spread on the wind |
| Arctic poppy | Flowers follow the Sun to soak up warmth |
| Purple saxifrage | Blooms early; it’s Nunavut’s territorial flower |
Common plant adaptations:
- growing low to the ground to avoid wind
- dark or hairy leaves to absorb heat
- shallow roots above the permafrost
- growing and flowering very quickly in the short summer
Animals
| Animal | Adaptations |
|---|---|
| Caribou | Hollow hairs trap heat; wide hooves act like snowshoes; migrate long distances |
| Muskox | Very long hair (qiviut) is one of the warmest natural fibres; herds circle to protect calves |
| Arctic fox | Thick fur; turns white in winter; small ears reduce heat loss |
| Polar bear | Thick fat and fur; hunts seals on sea ice |
| Snowy owl | Feathered feet; white camouflage |
| Lemmings | Live under the snow in winter; populations boom and crash |
| Ptarmigan | Feathered feet; turns white in winter |
In summer, millions of migrating birds, like snow geese and Arctic terns, arrive to nest. Swarms of mosquitoes and blackflies hatch from the many ponds.
People of the tundra
Inuit, Inuvialuit, Dene, Gwich’in and other Indigenous peoples have lived on the Arctic tundra for thousands of years. Their knowledge of the land, animals and ice is vital to understanding how the tundra is changing. Traditional foods include caribou, seal, char and berries.
A tundra under threat
The Arctic is warming about three to four times faster than the global average.
| Change | Effect |
|---|---|
| Thawing permafrost | Ground sinks and buckles, damaging roads and buildings; releases carbon dioxide and methane, which cause more warming |
| Shrubs and trees moving north | The treeline is creeping north in some places |
| Shrinking sea ice | Polar bears lose hunting platforms |
| Changing caribou herds | Many herds have declined sharply |
Common mistakes
- Thinking the tundra is always covered in snow. In summer, it bursts with flowers.
- Thinking the tundra gets lots of snow. It gets very little precipitation.
- Thinking nothing lives there.
Try it yourself
- Compare the size of an Arctic willow with a willow tree in a park. Why are they so different?
- Put two ice cubes in a dish, one on a dark cloth and one on a white cloth, in the sun. Relate the result to tundra plant adaptations.
- Find the treeline on a map of Canada.
Quick recap
- The tundra is a cold, treeless biome with long winters and short summers.
- Arctic tundra has permafrost; alpine tundra is found high on mountains.
- Small plants grow close to the ground and grow quickly in summer.
- Animals have thick fur, fat and camouflage; many migrate.
- Climate change is thawing permafrost and transforming the tundra.