Climate Change and the Glacial Realms

Photo courtesy: Dr. Rasik Ravindra
Temperatures in the Arctic are increasing twice as fast as the global average —the most rapid warming being recorded during winter.

Abstract: The cryosphere acts as sensitive thermometers recording the fluctuations in the climate. The Antarctic, the Arctic and the Himalaya are all showing signs of increasing ice mass loss on a decadal scale as a consequence of average rise of 0.8 oC in global temperatures since 1880 (IPCC, 2013). The meteorological observatories in the Arctic, the Antarctic and Tibet—demonstrate a rise in temperature over the last three decades.

Term Power

What is ...

Calving is when chunks of ice break off at the terminus, or end of a glacier. Ice breaks because the forward motion of a glacier makes the terminus unstable. Then glacial calving occurs at the coasts—these resulting chunks are called 'icebergs'.

Moraines are accumulation of rock debris (till) carried or deposited by a glacier. The material, which ranges in size from blocks or boulders (usually faceted or striated) to sand and clay, is unstratified when dropped by the glacier and shows no sorting or bedding.

A subglacial lake is a permanent lake under a glacier, typically an ice cap or ice sheet. Subglacial lakes are usually formed due to the action of geothermal activity or the pressure exerted by the overlaying ice.

A crevasse is a deep, wedge-shaped opening in a glacier or ice sheet. Crevasses usually form in the top 50 m of a glacier, where the ice is brittle. Below that, a glacier is less brittle and can slide over uneven surfaces without cracking. The inflexible upper portion may split as it moves over the changing landscape.

A drumlin is an oval or elongated hill believed to have been formed by the erstwhile streamlined movement of glacial ice sheets across rock debris, or till.

Glacier mass balance is the difference between accumulation and ablation of a glacier in terms of the difference in thickness of snow from the previous measurement.

The process by which a layer of ice builds up on solid objects that are exposed to freezing precipitation or to supercooled fog or cloud droplets. At the earth’s surface this frequently leads to the formation of ice glazes.

An ice core is a cylinder-shaped sample of ice drilled from a glacier. Ice core records provide the most direct and detailed way to investigate past climate and atmospheric conditions.

Antarctic Circumpolar Current, also called West Wind Drift, surface oceanic current encircling Antarctica and flowing from west to east. It is Earth’s largest ocean current with the volume of water transported said to be at least 25,000,000 cubic m.

An ice shelf is a thick mass of floating ice that is attached to land, formed from and fed by tongues of glaciers extending outward from the land into sheltered waters.

Permafrost is perennially frozen ground, a naturally occurring material with a temperature colder than 0 °C (32 °F) continuously for two or more years. Such a layer of frozen ground is designated exclusively on the basis of temperature.

When glaciers melt faster than they are replenished by precipitation, the total volume decreases. The glacier shrinks. This is called a glacial retreat. The glacier is not actually physically moving up, but only appears to do so.

Albedo is the fraction of light that is reflected by a body or surface. Ice and snow being white in colour exhibit high albedo, i.e. reflectance of solar heat.

The Antarctic Treaty is an agreement signed by 12 nations, in which Antarctic was made a demilitarised zone to be preserved for scientific research. The Treaty resulted from a conference in Washington, D.C.

Black Carbon is any of a group of intensely black, finely divided forms of amorphous carbon, usually obtained as soot from partial combustion of hydrocarbons. Their deposition on frozen matter can cause the matter to melt.