Greenland’s icecap has thickened slightly in recent years despite concerns that it is thawing out due to global warming, says an international team of scientists.
A team led by Professor Ola Johannessen, at the Nansen Environmental and Remote Sensing Center in Norway, report their findings online ahead of print publication in the journal Science.
The 3,000-metre thick Greenland icecap is a key concern in debates about climate change because a total melt would raise world sea levels by about 7 metres. And a runaway thaw might slow the Gulf Stream that keeps the North Atlantic region warm.
Glaciers at sea level have been retreating fast because of a warming climate, making many other scientists believe the entire icecap is thinning.
But satellite measurements showed that more snowfall is falling and thickening the icecap, especially at high altitudes, say Johannessen and team.
“The overall ice thickness changes are … approximately plus 5 centimetres a year or 54 centimetres over 11 years.”
But, they say, the thickening seems consistent with theories of global warming, blamed by most experts on a build-up of heat-trapping gases from burning fossil fuels in power plants, factories and cars.
Warmer air, even if it is still below freezing, can carry more moisture. That extra moisture falls as snow below 0°C.
And the scientists say that the thickening of the icecap might be offset by a melting of glaciers around the fringes of Greenland. Satellite data is not good enough to measure the melt nearer sea level.