DATE: December 10, 2019
SNIP: Greenland is losing ice seven times faster than it was in the 1990s.
The assessment comes from an international team of polar scientists who’ve reviewed all the satellite observations over a 26-year period.
They say Greenland’s contribution to sea-level rise is currently tracking what had been regarded as a pessimistic projection of the future.
It means an additional 7cm of ocean rise could now be expected by the end of the century from Greenland alone.
This threatens to put many millions more people in low-lying coastal regions at risk of flooding.
It’s estimated roughly a billion live today less than 10m above current high-tide lines, including 250 million below 1m.
“Storms, if they happen against a baseline of higher seas – they will break flood defences,” said Prof Andy Shepherd, of Leeds University.
“The simple formula is that around the planet, six million people are brought into a flooding situation for every centimetre of sea-level rise. So, when you hear about a centimetre rise, it does have impacts,” he told BBC News.
Whereas in the early 90s, the rate of loss was equivalent to about 1mm per decade, it is now running at roughly 7mm per decade.
Imbie team-member Dr Ruth Mottram is affiliated to the Danish Meteorological Institute.
She said: “Greenland is losing ice in two main ways – one is by surface melting and that water runs off into the ocean; and the other is by the calving of icebergs and then melting where the ice is in contact with the ocean. The long-term contribution from these two processes is roughly half and half.”
In an average year now, Greenland sheds about 250 billion tonnes of ice. This year, however, has been exceptional for its warmth. In the coastal town of Ilulissat, not far from where the mighty Jakobshavn Glacier enters the ocean, temperatures reached into the high 20s Celsius. And even in the ice sheet interior, at its highest point, temperatures got to about zero.
“The ice loss this year was more like 370 billion tonnes,” said Dr Mottram.