The tundra is a distinct biome defined by its treeless landscape and consistently cold climate. This environment is one of the coldest on Earth, characterized by a unique geography that limits plant life to low-lying shrubs, mosses, and lichens. Tundra biomes are globally distributed, primarily located in the highest latitudes of the Northern Hemisphere and on the peaks of high mountain ranges worldwide.
Environmental Conditions Defining Tundra Locations
The presence of extremely low temperatures and a very short growing season dictate the global positioning of the tundra biome. Tundra winters are long and dark, with mean temperatures often remaining below \(0^\circ\text{C}\) for six to ten months of the year. Even during the brief summer, temperatures only rise slightly, usually ranging between \(3^\circ\text{C}\) and \(12^\circ\text{C}\).
The most fundamental geographic constraint defining a true tundra environment is permafrost—ground that remains frozen for at least two consecutive years. This permanently frozen layer prevents deep root growth, limiting vegetation to shallow-rooted species. Although the tundra receives low precipitation, the permafrost prevents water drainage, leading to boggy conditions during the summer thaw.
Global Distribution of Arctic Tundra
The Arctic Tundra, the most extensive type of this biome, is found encircling the North Pole. This vast, circumpolar area continuously rings the Arctic Ocean, generally located above the \(60^\circ\text{N}\) latitude line, forming a transition zone between the polar ice caps and the boreal forests (taiga).
North America
In North America, the Arctic Tundra covers significant portions of the continent’s northern reaches. This includes nearly all of the northern coast of Alaska and a large portion of northern Canada, extending across the Yukon, Northwest Territories, and Nunavut. The ice-free coastal areas of Greenland are also part of this expansive biome.
Eurasia
The Arctic Tundra continues its circumpolar distribution across Eurasia. It dominates the northern edge of Russia, particularly the vast expanse of Siberia, including the Taymyr and Kamchatka Peninsulas. Smaller sections are also located in Northern Europe, specifically across the northern parts of Norway, Sweden, and Finland. The southern limit follows the northern edge of the coniferous forest belt.
Alpine Tundra: Location by Altitude
Unlike the Arctic Tundra, the Alpine Tundra is defined by elevation rather than latitude, meaning it can be found on mountain ranges worldwide. This biome occurs above the “tree line,” the elevation beyond which temperatures are too low and winds are too strong to support the growth of trees. The high altitude creates a climate that mimics polar conditions due to adiabatic cooling, even in tropical or temperate zones.
The elevation of the tree line varies significantly depending on the mountain’s latitude and local climate conditions. For instance, in the Rocky Mountains of North America, the tree line generally occurs between 11,000 and 11,500 feet. Conversely, closer to the equator, such as in the Andes Mountains of South America, the Alpine Tundra begins at much higher elevations, often between 11,500 and 13,100 feet.
Specific examples of the Alpine Tundra’s global presence include the Himalayas in Asia, the European Alps, and the North American Cordillera, which encompasses the Rockies. A key difference is that Alpine Tundra typically lacks the continuous permafrost layer that characterizes the Arctic Tundra, although patchy permafrost may still be present.