Greenland’s Melting Ice Sheet

Greenland ice sheet

Greenland is home to the world’s second largest ice sheet, and it is melting at an alarming rate – 287 billion metric tons of ice is disappearing every year. (Photo credit: Global Warming Images / Alamy Stock Photo)

Greenland is home to the world’s second largest ice sheet, and it is melting at an alarming rate – 287 billion metric tons of ice is disappearing every year. Several factors contribute to ice sheet melting, including changes in air temperature, water temperature, and precipitation. New research indicates that there is a fourth factor to consider: cloud cover.

According to an article published recently in Nature Communications, cloud cover can intensify the quantity of meltwater that runs off the surface of a glacier. Clouds trap heat on Earth’s surface, causing local temperatures to increase. You might conclude that these increased temperatures might be most dramatic during the day. However, it turns out that the affect of cloud cover is most significant at night. When skies are clear at night, any residual heat escapes into space. But when the skies are cloudy, heat emitted by Earth’s surface is trapped by the clouds and bounces back toward Earth. This prevents any ice that melted during the day from refreezing, as would occur on a clear, cloudless night.

Kristof Van Tricht, a PhD student in Department of Earth and Environmental Sciences at Belgium’s University of Lueven, and his colleagues used satellite observations from 2007 to 2010 to detect clouds over the Greenland ice sheet. The researchers then combined the satellite data with ground-level observations, snow model simulations, and climate model data to map the total impact of cloud cover.

“Over the entire Greenland ice sheet, clouds raise the temperature, which triggers additional meltwater runoff: 56 billion tons per year – a third more than clear skies,” Van Tricht said in a statement about the research. “A snowpack is like a frozen sponge that melts during the day. At night, clear skies make a large amount of meltwater in the sponge refreeze. When the sky is overcast, by contrast, the temperature remains too high and only some of the water refreezes. As a result, the sponge is saturated more quickly and excess meltwater drains away.”

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Country: Greenland

Location: Greenland is an island located between the Arctic Ocean and the North Atlantic Ocean.

Area: 2,166,086 sq km (land and water) (a little over three times the size of Texas)

Climate: Greenland has an arctic to subarctic climate.

Terrain: The terrain of Greenland is a flat to gradually sloping icecap that covers everything except a narrow, mountainous, barren, rocky coast.

Natural Resources:  Coal, diamonds, fish, gold, hydropower, iron ore, lead, molybdenum, niobium, platinum,  possible oil and gas, seals, tantalite, uranium, whales,  zinc

Economics: $2.133 billion (est. 2011)

Environmental Issues: Climate change, protection of the arctic environment; preservation of the Inuit traditional way of life, including whaling and seal hunting

Source: CIA – The World Factbook (https://www.cia.gov/library/publications/the-world-factbook/geos/gl.html)

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