Greenland ice-sheet melting fast

Posted: 16 August 2004

A report by the BBC's science correspondent, David Shukman, highlights new research which shows that Greenland's ice-sheet is melting 10 times faster than previously thought. If the entire ice-sheet were to melt, the global sea level would rise by seven metres, enough to swamp most of London.

Shukman, one of the few reporters to have ever visited the ice-sheet, was given exclusive access to the new findings from a study by the Geological Survey of Denmark and Greenland (GEUS).

The last big study of Greenland's ice-sheet was by NASA four years ago. Then, observations by satellite and aircraft found that the margins of Greenland's ice-sheet were dropping in height at the rate of roughly one metre every year.

Rapid melting

Now the new study by GEUS has come to a far more alarming conclusion. Scientist have recently discovered that the ice-sheet is falling in height by about 10 metres a year - in places it is dropping at the rate of one metre a month.

Graphic showing elevation changes of Greenland icesheet. Image: NASA
Graphic showing elevation changes of Greenland icesheet. Image: NASA
Elevation changes in cm/yr on the Greenland Ice Sheet from airborne laser altimetry detected during the PARCA campaign (ref.: http://aol.wff.nasa.gov/aoltm.html). Blue colour tones indicate areas of thinning.
The Sermilik glacier in southern glacier which Shukman visited is so unsteady that one automatic monitoring station was swallowed up by a huge crevasse which developed in the ice. Much has changed in just a century. Engravings from the late 19th century show the glacier reaching far into the ocean. Today, satellite pictures trace the extraordinary retreat of the ice - the glacier has fallen by an astounding 150 metres in the last 15 years.

Asked by Shukman what was causing the rapid melting, Dr Carl Boggild a lead scientist with GEUS, said he believed that accelerating melt was due to unusually "warm winters and warm summers." The rising temperatures recorded here are at least is partly responsible for the speed-up of melting, according to Dr Boggild.

Studying the physics of how the air and ice relate, Dr Boggild and his research team conclude that as much as 55 per cent of the melting is attributable to warming air temperatures.

However, he is cautious to heap all the blame on climate change: "Maybe if we look back after 50 years and see how temperatures have risen, then we can call it climate change."

New farmers

So what do the locals think of their changing climate? For many, the warmer temperatures bring new prospects. Ferdinand Egerday and his family has started cultivating potatoes - something not seen in Greenland since the warmer times of the Vikings. In the year 2000 Egerday says, the climate got warmer. Before that, the sea froze solid in winter. "Compared to former times it feels like it's getting warmer now. The summers are more warm in July and August and that's what makes it possible to grow more than before," says Egerday.

Niels-Hinrik Lynge a local journalist is wary of the future. "Because we live in a cold country we have difficulty in competing with the world because of our climate so, I don't know, may be it's going to be good for us that it's getting warmer but it's not good for you and for your future."

Greenland, says Shukman, is at the front line of global climate change. Although according to most estimates the ice-sheet would take hundreds of years to melt completely, the impact of the many icebergs collapsing into the sea will be felt far beyond Greenland. The melting ice will cause the sea level to rise and the injection of freshwater from the ice mixing with the saltwater from the ocean could affect the ocean currents, shutting down the Gulf Stream which keeps Europe warm.

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