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Current Affairs

Greenland glaciers to melt faster

Date: 19 November 2020 Tags: Climate Change

Issue

The three largest glaciers in Greenland could melt faster than even the worst-case warming predictions, according to researchers.

 

Background

Over the last two decades, the world's ice sheets atop Greenland and Antarctica have become the single largest source of sea level rise.

 

Details

  • A team of researchers used historical images and a host of other data to estimate how much ice had been lost from Greenland's Jakobshavn Isbrae, Kangerlussuaq Glacier, and Helheim Glaciers in the 20th century.

  • They found that Jakobshavn Isbrae lost more than 1.5 trillion tonnes of ice between 1880-2012, while Kangerlussuaq and Helheim lost 1.4 trillion and 31 billion tonnes from 1900–2012, respectively.

  • The UN's climate science advisory panel, the IPCC, has forecast sea level rise from all sources of between 30-110 centimetres by 2100, depending on emissions. 

  • The study found that if greenhouse gas emissions continued unabated, ice sheets in Greenland will shed some 36 trillion tonnes this century, enough to lift the global waterline some 10 centimetres.

 

Glacial landforms

 

Depositional

  • Esker: Built up bed of a sub-glacial stream.

  • Kame: Irregularly shaped mound.

  • Moraine: Feature can be terminal (at the end of a glacier), lateral (along the sides of a glacier), or medial (formed by the merger of lateral moraines from contributory glaciers).

  • Outwash fan: Braided stream flowing from the front end of a glacier.

  • Drumlin: It is an elongated hill in the shape of an inverted spoon or half-buried egg formed by glacial ice acting on underlying unconsolidated till or ground moraine.

 

Erosional

  • Cirque: Starting location for mountain glaciers

  • U-shaped or trough valley: U-shaped valleys are created by mountain glaciers. When filled with ocean water so as to create anthe glacial action erodes through, a spillway forms.

  • Valley step: an abrupt change in the longitudinal slope of a glacial valley.