The tundra biome is a cold, treeless ecosystem found in Arctic and alpine regions. It features permafrost, short growing seasons, low rainfall, and strong winds. In physical geography, a tundra is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. Tundra vegetation is composed of dwarf shrubs, sedges, grasses, mosses, and lichens. Scattered trees grow in some tundra regions. Want to explore more about this biome?
There are two main types of tundra: Arctic and Alpine.
Arctic Tundra
The Arctic tundra occurs in the far Northern Hemisphere (Arctic), north of the taiga belt. The word "tundra" usually refers only to the areas where the subsoil is permafrost, or permanently frozen soil. The Arctic tundra covers approximately 10% of Earth’s surface, primarily across the northern hemisphere.
Arctic tundra contains areas of stark landscape and is frozen for much of the year. The soil there is frozen from 25 to 90 cm (10 to 35 in) down, making it impossible for trees to grow there. There are two main seasons, winter and summer, in the polar tundra areas. During the winter it is very cold, dark, and windy with the average temperature around −28 °C (−18 °F), sometimes dipping as low as −50 °C (−58 °F). However, extreme cold temperatures on the tundra generally do not drop as low as those experienced in taiga areas further south (for example, Russia's, Canada's, and Alaska's lowest temperatures were recorded in locations south of the tree line).
The Arctic tundra experiences long, harsh winters and brief, cool summers. Summer temperatures range between 3 and 12 °C (37 to 54 °F) and last for only 50 to 60 days. Climatically, the Arctic tundra is more defined by low summer temperatures than winter lows, setting it apart from adjacent biomes like the taiga. Coastal tundra regions are generally cooler and foggier than inland zones, especially in late summer and early autumn due to high evaporation.
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During the summer, temperatures rise somewhat, and the top layer of seasonally-frozen soil melts, leaving the ground very soggy. The tundra is covered in marshes, lakes, bogs, and streams during the warm months. Generally daytime temperatures during the summer rise to about 12 °C (54 °F) but can often drop to 3 °C (37 °F) or even below freezing.
Arctic tundra tends to be windy, with winds often blowing upwards of 50-100 km/h (31-62 mph). It is also a polar desert, with only about 150-250 mm (6-10 in) of precipitation falling per year (the summer is typically the season of maximum precipitation). Although precipitation is light, evaporation is also relatively minimal. During the summer, the permafrost thaws just enough to let plants grow and reproduce, but because the ground below this is frozen, the water cannot sink any lower, so the water forms the lakes and marshes found during the summer months.
Arctic tundras are sometimes the subject of habitat conservation programs.
The biodiversity of tundras is low: 1,700 species of vascular plants and only 48 species of land mammals can be found, although millions of birds migrate there each year for the marshes. There are also a few fish species. There are few species with large populations.
Due to the harsh climate of Arctic tundra, regions of this kind have seen little human activity, even though they are sometimes rich in natural resources such as petroleum, natural gas, and uranium. In recent times this has begun to change in Alaska, Russia, and some other parts of the world: for example, the Yamalo-Nenets Autonomous Okrug produces 90% of Russia's natural gas.
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The Arctic tundra typically receives 6 to 10 inches (15 to 25 cm) of precipitation annually. Snow accumulations can reach 25 inches (64 cm), with rare instances exceeding 75 inches (191 cm). Although Arctic winds are typically weaker than in alpine zones, they still play a crucial role in shaping snowdrifts and triggering blizzard-like whiteout conditions, reducing visibility to under 10 meters (30 feet).
The tundra soil is rich in nitrogen and phosphorus. The soil also contains large amounts of biomass and decomposed biomass that has been stored as methane and carbon dioxide in the permafrost, making the tundra soil a carbon sink.
Tundra plants have developed remarkable adaptations to survive in an environment with extreme cold, permanent frost, low sunlight, and a very short growing season. Their low height, clumping growth patterns, and hairy stems help conserve heat and protect them from strong winds. Most tundra plants lack deep roots due to the permafrost. Despite harsh conditions, over 1,700 plant species inhabit the tundra, making it an ecologically significant biome. Importantly, tundra vegetation plays a major role in global carbon storage, acting as a carbon sink by absorbing more CO₂ than it emits.
Tundra animals are specially adapted to cope with frigid temperatures, limited food, and harsh winds. Many species, like the arctic fox and ptarmigan, grow white winter coats for camouflage in snow and switch to brown in summer. Unlike other biomes, tundra has no cold-blooded vertebrates due to the extreme cold.
Arctic Tundra Landscape.
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Alpine Tundra
Alpine tundra accounts for about 3% of Earth’s land surface, occurring in mountainous regions around the world at high elevations above the tree line. Alpine tundra does not contain trees because the climate and soils at high altitude block tree growth. Alpine tundra transitions to subalpine forests below the tree line; stunted forests occurring within the forest-tundra ecotone are known as Krummholz. Alpine tundra occurs in mountains worldwide.
The Alpine tundra, found atop high mountain ranges, has a more moderate but still cold climate compared to its Arctic counterpart. Summer temperatures range from -12 to 10 °C (10 to 50 °F), and the growing season can last up to 180 days, although nighttime freezes are common year-round. Because of its elevation, the alpine tundra is exposed to intense solar radiation due to the thinner atmosphere, which allows more sunlight to penetrate. Alpine tundra regions are especially known for strong, persistent winds, often exceeding 75-125 mph (120-200 km/h) in the upper reaches of mountain ranges like the Rockies and the Alps.
Alpine tundra tends to receive more precipitation than the Arctic tundra, averaging 12 inches (30 cm) yearly. For example, high elevations in the Rocky Mountains can receive up to 25 inches (64 cm) annually, while areas like the northwestern Himalayas may get less than 3 inches (7.6 cm).
In contrast to Arctic tundra, alpine tundra soils usually lack continuous permafrost due to steep slopes and better drainage. Soils here are also classified as Gelisols or similar types, depending on elevation and moisture. Topography, snow cover, and wind exposure heavily influence soil development and plant distribution in alpine zones.
Alpine Tundra in Colorado.
Antarctic Tundra
Antarctic tundra occurs on Antarctica and on several Antarctic and subantarctic islands, including South Georgia and the South Sandwich Islands and the Kerguelen Islands. Most of Antarctica is too cold and dry to support vegetation, and most of the continent is covered by ice fields or cold deserts. However, some portions of the continent, particularly the Antarctic Peninsula, have areas of rocky soil that support plant life.
The flora presently consists of around 300-400 species of lichens, 100 mosses, 25 liverworts, and around 700 terrestrial and aquatic algae species, which live on the areas of exposed rock and soil around the shore of the continent. In contrast with the Arctic tundra, the Antarctic tundra lacks a large mammal fauna, mostly due to its physical isolation from the other continents. Sea mammals and seabirds, including seals and penguins, inhabit areas near the shore, and some small mammals, like rabbits and cats, have been introduced by humans to some of the subantarctic islands.
The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline.
How tundra plants respond to climate change and what it means for future ecosystems
Tundra Soils
Tundra soils are uniquely shaped by the extreme climate, freeze-thaw cycles, and the presence or absence of permafrost. Only a thin active layer, typically 15 to 30 cm (6 to 12 inches) thick, thaws during the short summer and supports plant life.
Arctic tundra soils are typically classified as Gelisols (U.S. soil taxonomy system) or Cryosols (international system).
Indigenous Peoples and Modern Impact
Indigenous peoples such as the Inuit in North America, Sámi in Scandinavia, and Nenets in Siberia have developed sustainable lifestyles deeply connected to the tundra’s rhythms. Historically, these populations adapted by building insulated shelters, wearing fur clothing, and maintaining migratory patterns that followed food sources.
In modern times, non-Indigenous settlements, industrial operations (such as oil drilling), and military outposts have expanded into tundra regions, particularly in Alaska, northern Canada, and Russia.
Environmental Pressures and Climate Change
The tundra biome is facing increasing environmental pressures that threaten its delicate balance. A severe threat to tundra is climate change, which causes permafrost to thaw. The thawing of the permafrost in a given area on human time scales (decades or centuries) could radically change which species can survive there. It also represents a significant risk to infrastructure built on top of permafrost, such as roads and pipelines. Carbon emissions from permafrost thaw contribute to the same warming which facilitates the thaw, making it a positive climate change feedback.
One of the most concerning consequences is the thawing of permafrost, which releases large amounts of carbon dioxide (CO₂) and methane (CH₄), both potent greenhouse gases, into the atmosphere.
The effects of climate change on tundra regions have received extensive attention from scientists as well as policy makers and the public. This attention partly stems from the tundra’s high sensitivity to the general trend of global warming. While the average global surface-air temperature has risen by approximately 0.9 °C (about 1.5 °F) since 1900, average surface air temperatures in the Arctic have risen by 3.5 °C (5.3 °F) over the same period.
Many parts of the region have experienced several consecutive years of record-breaking winter warmth since the late 20th century. In some locations, this record-breaking winter warmth has been unprecedented; three-month winter mean temperatures in Norway’s Svalbard archipelago in 2016 were 8-11 °C (14.4-19.8 °F) higher than the 1961-90 average. Most climatologists agree that this warming trend will continue, and some models predict that high-latitude land areas will be 7-8 °C (12.6-14.4 °F) warmer by the end of the 21st century than they were in the 1950s.
Global warming has already produced detectable changes in Arctic and alpine tundra ecosystems. These ecosystems are being invaded by tree species migrating northward from the forest belt, and coastal areas are being affected by rising sea levels. Both phenomena are reducing the geographic extent of the Arctic tundra. Other changes occurring in both Arctic and alpine tundras include increased shrub density, an earlier spring thaw and a later autumn freeze, diminished habitats for native animals, and an accelerated decomposition of organic matter in the soil.
These processes can actually contribute to greater warming in the tundra than in other regions. For example, climatologists point out that the darker surfaces of green coniferous trees and ice-free zones reduce the albedo (surface reflectance) of Earth’s surface and absorb more solar radiation than do lighter-coloured snow and ice, thus increasing the rate of warming.
One of the most striking ongoing changes in the Arctic is the rapid melting of sea ice. Some climate models predict that, sometime during the first half of the 21st century, summer sea ice will vanish from the Arctic Ocean. An absence of summer ice would amplify the existing warming trend in Arctic tundra regions as well as in regions beyond the tundra, because sea ice reflects sunlight much more readily than the open ocean and, thus, has a cooling effect on the atmosphere.
In addition, research indicates that the retreat of sea ice would enhance the productivity of tundra vegetation, and the resulting buildup of plant biomass might lead to more extreme events such as large tundra fires. Finally, an ice-free Arctic Ocean would improve access to high northern latitudes for recreational and industrial activities; this would likely place additional stress on tundra plants and animals as well as compromise the resilience of the tundra ecosystem itself. In alpine tundras too, climate warming could encourage more human activity and increase damage to plant and animal populations there.
The fate of permafrost in a warmer world is a particularly important issue. Together, tundra and taiga account for approximately one-third of global carbon storage in soil, and a large portion of this carbon is tied up in permafrost in the form of dead organic matter. Some of this organic matter has been preserved for many thousands of years, not because it is inherently difficult to break down but because the land has remained frozen.
Thawing of the permafrost would expose the organic material to microbial decomposition, which would release carbon into the atmosphere in the form of CO2 and methane (CH4). Rates of microbial decomposition are much lower under anaerobic conditions, which release CH4, than under aerobic conditions, which produce CO2; however, CH4 has roughly 25 times the greenhouse warming potential of CO2.
The Arctic has been a net sink (or repository) of atmospheric CO2 since the end of the last ice age. At the same time, however, the region has been a net source of atmospheric CH4, primarily because of the abundance of wetlands in the region. Numerous other factors affect the exchange of carbon-containing compounds between the tundra and the atmosphere. Tundra fires release CO2 to the atmosphere, and there is evidence that climate warming over the past several decades has increased the frequency and severity of tundra burning in the Arctic. In contrast, greater plant productivity resulting from a longer, warmer growing season could compensate for some of the carbon emissions from permafrost melting and tundra fires.
Indeed, ecologists and climate scientists note that there is a great deal of uncertainty about the future of the carbon cycle in the Arctic during the 21st century. They worry, however, that a net transfer of greenhouse gases from tundra ecosystems to the atmosphere has the potential to exacerbate changes in Earth’s climate through a positive feedback loop, in which small increases in air temperature at the surface set off a chain of events that leads to further warming.
Tundra Existence in Africa
It's important to note that the term "tundra" is not typically associated with the African continent. Tundra biomes are characterized by extremely cold temperatures, low precipitation, and permafrost, conditions not generally found in Africa.
The Afrotropical realm is one of the Earth's eight biogeographic realms. Most of the Afrotropical realm, except for Africa's southern tip, has a tropical climate. South of the Sahara, two belts of tropical grassland and savanna run east and west across the continent, from the Atlantic Ocean to the Ethiopian Highlands.
The Afromontane region extends from the Ethiopian Highlands to the Drakensberg Mountains of South Africa, including the East African Rift. Characteristic plant communities include Miombo woodlands, drier mopane and Baikiaea woodlands, and higher-elevation Bushveld.
Southern Africa contains several deserts. The Namib Desert is one of the oldest deserts in the world and extends for over 2,000 kilometers along the Atlantic coasts of Angola, Namibia, and South Africa. It is characterized by towering dunes and a diversity of endemic wildlife. Further inland concerning the Namib Desert, the Kalahari Desert is a semi-arid savanna spanning Botswana, Namibia, and South Africa.
Afrotropical Realm Map.
The tropical environment is rich in terms of biodiversity. Tropical African forest is 18 percent of the world's total and covers over 3.6 million square kilometers of land in West, East, and Central Africa. In West Africa, a chain of rain forests up to 350 km long extends from the eastern border of Sierra Leone to Ghana.
The rate of deforestation in Africa is less known than the rate of other tropical regions. West African countries depend on products like gum, copal, rubber, cola nuts, and palm oil as a source of steady income. Land use change spoils entire habitats with the forests.
The rainforests that remain in West Africa now greatly differ in condition from their state 30 years ago. In Guinea, Liberia, and the Ivory Coast, there is almost no primary forest cover left unscathed; in Ghana, the situation is much worse, and nearly all of the rainforest is being removed. Guinea-Bissau loses 200 to 350 km2 (77 to 135 sq mi) of forest yearly, Senegal 500 km2 (190 sq mi) of wooded savanna, and Nigeria 6,000,050,000 of both. Liberia loses 800 km2 (310 sq mi) of forests each year. Extrapolating from present rates of loss, botanist Peter Raven pictures that the majority of the world's moderate and smaller rainforests (such as in Africa) could be destroyed in forty years.
In early 2007, scientists created an entirely new proxy to determine the annual mean air temperature on land-based on molecules from the cell membrane of soil-inhabiting bacteria. When applying this to the outflow core of the Congo River, the core contained eroded land material and microfossils from marine algae.
During the last ice age, African temperatures were 21 °C, about 4 °C lower than today, while the tropical Atlantic Ocean was only about 2.5 °C cooler. Lead author Johan Weijers and his colleagues concluded that the land-sea temperature difference has by far the largest influence on continental rainfall.
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