Glacier

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A glacier ( or ) is a persistent body of dense ice that is constantly moving under its own weight; it forms where the accumulation of snow exceeds its ablation (melting and sublimation) over many years, often centuries.wikipedia
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Snow

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A glacier ( or ) is a persistent body of dense ice that is constantly moving under its own weight; it forms where the accumulation of snow exceeds its ablation (melting and sublimation) over many years, often centuries.
Where the climate is cold enough for year-to-year accumulation, a glacier may form.

Cirque

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They also abrade rock and debris from their substrate to create landforms such as cirques and moraines. Cirque glaciers form on the crests and slopes of mountains.
A cirque (French, from the Latin word circus) is an amphitheatre-like valley formed by glacial erosion.

Ice sheet

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On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions, but glaciers may be found in mountain ranges on every continent including Oceania's high-latitude oceanic island countries such as New Zealand and Papua New Guinea.
An ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than 50000 km2.

Crevasse

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Glaciers slowly deform and flow due to stresses induced by their weight, creating crevasses, seracs, and other distinguishing features.
A crevasse is a deep crack, or fracture, found in an ice sheet or glacier, as opposed to a crevice that forms in rock.

Sea ice

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Glaciers form only on land and are distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water.
Sea ice may be contrasted with icebergs, which are chunks of ice shelves or glaciers that calve into the ocean.

Fresh water

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Glacial ice is the largest reservoir of fresh water on Earth.
Fresh water includes water in ice sheets, ice caps, glaciers, icebergs, bogs, ponds, lakes, rivers, streams, and even underground water called groundwater.

Retreat of glaciers since 1850

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Since glacial mass is affected by long-term climatic changes, e.g., precipitation, mean temperature, and cloud cover, glacial mass changes are considered among the most sensitive indicators of climate change and are a major source of variations in sea level.
Studied by glaciologists, the temporal coincidence of glacier retreat with the measured increase of atmospheric greenhouse gases is often cited as an evidentiary underpinning of global warming.

Water resources

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Many glaciers from temperate, alpine and seasonal polar climates store water as ice during the colder seasons and release it later in the form of meltwater as warmer summer temperatures cause the glacier to melt, creating a water source that is especially important for plants, animals and human uses when other sources may be scant.
97% of the water on the Earth is salt water and only three percent is fresh water; slightly over two thirds of this is frozen in glaciers and polar ice caps.

Serac

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Glaciers slowly deform and flow due to stresses induced by their weight, creating crevasses, seracs, and other distinguishing features.
A serac (originally from Swiss French sérac) is a block or column of glacial ice, often formed by intersecting crevasses on a glacier.

Meltwater

glacial meltwatermeltwatersGlacial Meltwater Channel
Many glaciers from temperate, alpine and seasonal polar climates store water as ice during the colder seasons and release it later in the form of meltwater as warmer summer temperatures cause the glacier to melt, creating a water source that is especially important for plants, animals and human uses when other sources may be scant.
Meltwater is water released by the melting of snow or ice, including glacial ice, tabular icebergs and ice shelves over oceans.

Sea level rise

rising sea levelssea-level risesea level change
Since glacial mass is affected by long-term climatic changes, e.g., precipitation, mean temperature, and cloud cover, glacial mass changes are considered among the most sensitive indicators of climate change and are a major source of variations in sea level.
The acceleration is due mostly to human-caused global warming, which is driving thermal expansion of seawater and melt of land-based ice sheets and glaciers.

Blue ice (glacial)

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A large piece of compressed ice, or a glacier, appears blue, as large quantities of water appear blue.
Blue ice occurs when snow falls on a glacier, is compressed, and becomes part of the glacier.

Patagonia

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Continental glaciers cover nearly 5 e6sqmi or about 98 percent of Antarctica's 5.1 e6sqmi, with an average thickness of 7,000 ft. Greenland and Patagonia also have huge expanses of continental glaciers.
The high rainfall against the western Andes (Wet Andes) and the low sea surface temperatures offshore give rise to cold and humid air masses, contributing to the ice-fields and glaciers, the largest ice-fields in the Southern hemisphere outside of Antarctica.

New Guinea

PapuaPapua New GuineanNew Guinea island
Between 35°N and 35°S, glaciers occur only in the Himalayas, Andes, Rocky Mountains, a few high mountains in East Africa, Mexico, New Guinea and on Zard Kuh in Iran.
The tree line is around 4000 m elevation and the tallest peaks contain permanent equatorial glaciers—which have been retreating since at least 1936.

Glacial period

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The process of glacier establishment, growth and flow is called glaciation.
A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances.

Glaciology

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The corresponding area of study is called glaciology.
Glaciology (from Latin: glacies, "frost, ice", and Ancient Greek: λόγος, logos, "subject matter"; literally "study of ice") is the scientific study of glaciers, or more generally ice and natural phenomena that involve ice.

Nunatak

nunataksnunataqan exposed area
Only nunataks protrude from their surfaces.
A nunatak (from Inuit nunataq) is an exposed, often rocky element of a ridge, mountain, or peak not covered with ice or snow within (or at the edge of) an ice field or glacier.

Mountain

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Cirque glaciers form on the crests and slopes of mountains.
Mountains erode slowly through the action of rivers, weather conditions, and glaciers.

Climate change

climatic changeclimatechanging climate
Since glacial mass is affected by long-term climatic changes, e.g., precipitation, mean temperature, and cloud cover, glacial mass changes are considered among the most sensitive indicators of climate change and are a major source of variations in sea level.
There were various competing theories about these changes, and James Hutton, whose ideas of cyclic change over huge periods of time were later dubbed uniformitarianism, was among those who found signs of past glacial activity in places too warm for glaciers in modern times.

Cryosphere

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Glaciers are important components of the global cryosphere.
The cryosphere (from the Greek κρύος kryos, "cold", "frost" or "ice" and σφαῖρα sphaira, "globe, ball" ) is those portions of Earth's surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps, ice sheets, and frozen ground (which includes permafrost).

Ice shelf

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They contain vast quantities of fresh water, enough that if both melted, global sea levels would rise by over 70 m. Portions of an ice sheet or cap that extend into water are called ice shelves; they tend to be thin with limited slopes and reduced velocities.
An ice shelf is a thick suspended platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface.

Rocky Mountains

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Between 35°N and 35°S, glaciers occur only in the Himalayas, Andes, Rocky Mountains, a few high mountains in East Africa, Mexico, New Guinea and on Zard Kuh in Iran.
These ice ages left their mark on the Rockies, forming extensive glacial landforms, such as U-shaped valleys and cirques.

Mertz Glacier

Mertz Glacier Tongue
Some drain directly into the sea, often with an ice tongue, like Mertz Glacier.
Mertz Glacier (-67.5°N, 144.75°W) is a heavily crevassed glacier in George V Coast of East Antarctica.

Tidewater glacier cycle

tidewater glacieradvancingTidewater glaciers
Tidewater glaciers are glaciers that terminate in the sea, including most glaciers flowing from Greenland, Antarctica, Baffin and Ellesmere Islands in Canada, Southeast Alaska, and the Northern and Southern Patagonian Ice Fields.
The tidewater glacier cycle is the typically centuries-long behavior of tidewater glaciers that consists of recurring periods of advance alternating with rapid retreat and punctuated by periods of stability.

Iceberg

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As the ice reaches the sea, pieces break off, or calve, forming icebergs.
An iceberg or ice mountain is a large piece of freshwater ice that has broken off a glacier or an ice shelf and is floating freely in open water.