Danish researchers are calling for the models used it forecast sea level rise to be changed after their research shows that Greenland’s ice-cap is not melting more quickly, but rather in bursts.
The group’s research, which has been published this week in the Science magazine, shows that the speed at which Greenland’s ice-cap melts, rises and falls in different periods.
“It’s controversial and probably also the reason that Science decided to publish it as it moves us along in understanding the dynamism of the ice-cap,” Natural History Museum Research Chief Kurt Kjær tells videnskab.dk.
Up to now scientists have believed that Greenland’s ice was melting faster and have used the hypothesis in developing many of the climate models that are now used to calculate future sea-water levels.
“The bottom line is that it’s not going to happen as quickly as people have feared,” Kristian Kjeldsen who is another of the researchers tells TVA.
By studying aerial photographs of northwest Greenland back to the 1980s, as well as more recent satellite photographs, the researchers mapped the ice-cap over the past 30 years.
This showed that Greenland’s glaciers lost large amounts of ice between 1985 and 1992, but that they then stabilised so much that the losses stopped over 10 years.
In 2004 the dynamic ice mass loss began again and has continued until now – but the researchers believe that the current losses will also stop.
“We can see that the dynamic ice mass loss is not in constant acceleration as we have believed until now. The rapid loss that we currently have is a periodic event,” Institute of Space Research and Technology Shfaqat Abbas Khan tells videnskab.dk.
The researchers believe that the current models must be updated if they are to be able to forecast accurately.
“If the new results are not incorporated in the climate models, we may overestimate sea level rise,” Khan says.
The team says it cannot dismiss the idea that climate change can intensify the periodic thaw.
“I believe that there have been other dynamic losses in Greenland during all eras. But we don’t know yet whether global warming has intensified them,” says Kurt Kjær.
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Edited by Julian Isherwood