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Ice desert with ground pattern characteristic of freeze-thaw alternationIce deserts are the regions of Earth that fall under an
ice cap climate upright=1.4, Effect of Sun angle on climate, Solar radiation has a lower intensity in polar regions because it travels a longer distance through the atmosphere, and is also spread across a larger surface area due to its oblique angle of approach. A ...
(''EF'' under the Köppen classification). Despite rainfall totals low enough to normally classify as a
desert upright=1.5, alt=see caption, Sand dunes in the Rub' al Khali ("Empty quarter") in the United Arab Emirates">Rub'_al_Khali.html" ;"title="Sand dunes in the Rub' al Khali">Sand dunes in the Rub' al Khali ("Empty quarter") in the United Arab ...
, polar deserts are distinguished from true deserts (' or ' under the Köppen classification) by low annual temperatures and
evapotranspiration Evapotranspiration (ET) is the sum of water evaporation and transpiration from a surface area to the atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and water bodies. Tra ...

evapotranspiration
. Most polar deserts are covered in
ice sheet In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacier, glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctic ice sheet, Antarctica and Greenland ice sheet, G ...

ice sheet
s,
ice field An ice field (also spelled icefield) is a large area of interconnected glaciers, usually found in a mountainous region. They are often found in the colder climates and higher altitudes of the world where there is sufficient precipitation for th ...
s, or
ice cap upright=1.35, Vatnajökull, Iceland ">Iceland.html" ;"title="Vatnajökull, Iceland">Vatnajökull, Iceland In glaciology, an ice cap is a mass of ice that covers less than of land area (usually covering a highland area). Larger ice masses coveri ...
s. Polar deserts are one of two polar
biome A biome is a collection of plants Plants are mainly multicellular organisms, predominantly photosynthetic Photosynthesis is a process used by plants and other organisms to Energy transformation, convert light energy into chemical en ...
s, the other being Arctic
tundra In physical geography, tundra () is a type of biome A biome is a collection of plants and animals that have common characteristics for the environment they exist in. They can be found over a range of continents. Biomes are distinct biologic ...

tundra
. These biomes are located at the poles of Earth, covering much of the
Antarctic The Antarctic (US English or , UK English or and or ) is a polar region around Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. About 29% of Earth's surface is land consisting ...
in the southern hemisphere, and in the northern hemisphere extending from the
Arctic The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Alaska (United States), Canada, Finland, Greenland (Danish Realm, Den ...

Arctic
into
North America North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also be described as the northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to ...

North America
,
Europe Europe is a continent A continent is one of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven regions are commonly regarded as continents. Ordered from largest ...

Europe
and
Asia Asia () is Earth's largest and most populous continent, located primarily in the Eastern Hemisphere, Eastern and Northern Hemisphere, Northern Hemisphere of the Earth, Hemispheres. It shares the continental landmass of Eurasia with the conti ...
. Unlike the tundra that can support plant and animal life in the summer, polar deserts are largely barren environments, comprising permanent, flat layers of ice; due to the scarcity of liquid water, the same is also true of the few ice-free areas. However, there is evidence of some life in this seemingly inhospitable landscape: sediments of organic and inorganic substances in the thick ice hosting microbial organisms closely related to
cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum (biology), phylum of Gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), giving them their other name, "blue-green algae", t ...
, able to fix carbon dioxide from the melting water. Temperature changes in polar deserts frequently cross the freezing point of water. This "freeze-thaw" alternation forms patterned textures on the ground, as much as in diameter. Most of the interior of Antarctica is polar desert, despite the thick ice cover. Conversely, the
McMurdo Dry Valleys and the Dry Valleys The McMurdo Dry Valleys are a row of largely Antarctic oasis, snow-free valleys in Antarctica Antarctica ( or ) is Earth's southernmost continent. It contains the geographic South Pole and is situated in the Antarctic ...
of
Antarctica Antarctica ( or ) is Earth's southernmost continent. It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Oce ...

Antarctica
, although they have had no ice for thousands of years due to
katabatic wind A katabatic wind (named from the Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is approxi ...
but contain ephemeral streams and
hypersaline lake A hypersaline lake is a landlocked body of water that contains significant concentrations of sodium chloride or other Salt (chemistry), salts, with saline water, saline levels surpassing that of ocean water (3.5%, i.e. ). Specific microbial spec ...
s characteristic of extreme non-polar deserts, are not necessarily polar desert. Polar deserts are relatively common during
ice age An ice age is a long period of reduction in the temperature of Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and ...

ice age
s, as ice ages tend to be dry. Climate scientists have voiced concerns about the effects of
global warming Contemporary climate change includes both the global warming caused by humans, and its impacts on Earth's weather patterns. There have been previous periods of climate change, but the current changes are more rapid than any known event ...

global warming
to the ice poles in these polar biomes.


See also

*
Desert upright=1.5, alt=see caption, Sand dunes in the Rub' al Khali ("Empty quarter") in the United Arab Emirates">Rub'_al_Khali.html" ;"title="Sand dunes in the Rub' al Khali">Sand dunes in the Rub' al Khali ("Empty quarter") in the United Arab ...
*
Desertification Desertification is a type of land degradation Land degradation is a process in which the value of the biophysical environment is affected by a combination of human-induced processes acting upon the land. It is viewed as any change or distur ...
*
List of deserts by area This is a list of the largest desert, deserts in the world by area. It includes all deserts above . References {{DEFAULTSORT:List Of Deserts By Area Lists of landforms, Deserts By Area Deserts, * Geology-related lists, Des ...
* List of deserts by continent *
Tundra In physical geography, tundra () is a type of biome A biome is a collection of plants and animals that have common characteristics for the environment they exist in. They can be found over a range of continents. Biomes are distinct biologic ...

Tundra


References

Landforms Deserts {{Topography-stub es:Desierto polar