Stunning pictures of glaciers from space reveal worrying signs Earth’s ice is melting away

By Claire Bates

These awe-inspiring images of glaciers are helping scientists to determine just how quickly our planet is heating up. The huge ice fields are thought to be one of the most reliable indicators of climate change and are best studied from space.

The features form when snow accumulates on an area of land over tens to hundreds of years. It eventually becomes so thick and heavy that it forms dense glacial ice. When enough ice is compacted it beings to flow downhill or spread across flat land.

chile glacierGrey Glacier in Chile: The ice field covered 104 square miles in 1996. This 2007 picture from the International Space Station revealed it had dramatically receded. Scientists think increased regional temperatures has reduced the amount of ice being replenished each year

Nasa scientist Dorothy Hall said: ‘Glaciers that tend to be good climate indicators are small-land based, non-surge type glaciers. They respond directly to both regional temperature and snow.’

She and a team of scientists from around the world have used satellites to monitor changes in these glaciers in Europe, Iceland and Alaska. Glaciers tend to extend in many different directions with one part retracting while another part stays still. Therefore satellites such as Landsat 5 are essential as they can measure the entire rim by analysing the different wavelengths of light bounced back from the ice.

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However, it is not known for certain whether glaciers that are receding around the edges are also becoming thinner near the centre because visible satellite sensors cannot penetrate the surface of the ice. Most scientists assume that receding glaciers are also losing mass.

heiltskuk ice fieldThe vast Heiltskuk Ice Field in British Columbia covers nearly 1,400 square miles. This 2009 photo captures several of the ice fields valley glaciers that carve out large U-shaped valleys

(L) Mount Rainier in Washington hosts the Emmons Glacier. It is considered the most hazardous volcano in the U.S because of the risk of flooding from melting glaciers during an eruption. (R) Bear Glacier in Alaska, 2006: The hue is caused by the silt that is finely ground away from the valley walls. The stripes down the middle are formed from rocks and debris when two glaciers merge.  In 2008 the lake broke through and drained into Resurrection Bay

Professor Hall said: ‘It is very hard to measure volume changes in glaciers. People are required to put stakes in the glacier and come back a year later to see how much of a change there is in the height of the glaciers.’

On average scientists are finding that glaciers across the globe are steadily shrinking, which confirms suspicions that the world is heating up.

Helheim GlacierRetreat of the Helheim Glacier, Greenland, 2003: When the ice thins the tip of a glacier starts to float and rapidly cracks into icebergs, creating a calving edge, as captured here by Nasa’s Terra Satellite. Glacier looks pale blue because ice absorbs red wavelengths of light and scatters blue

An expert at Nasa’s Earth Observatory said: ‘Researchers generally believe the warming trend may be the result of natural, cyclical changes of the Earth’s climate, and possibly in combination with effects of the large-scale burning of fossil fuels by humans since the industrial revolution.’

The last time Earth warmed extensively was 120,000 years ago. The Greenland ice sheet drained into the ocean and the sea rose 20ft above current levels. If this happened today it would flood coastal communities and countries including Holland and Bangladesh.

Erebus Ice TongueErebus Ice Tongue, Antarctica, 2004: The saw-shaped projection jutting out from this glacier is a long, narrow sheet of ice almost 7 miles long and 33 feet high. During the summer when the rest of the sea ice melts, the ice tongue floats on the water without thawing. It is then carved by waves.
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