By Jonathan Amos
A new assessment from Europe’s CryoSat spacecraft shows Greenland to be losing about 375 cu km of ice each year.
Added to the discharges coming from Antarctica, it means Earth’s two big ice sheets are now dumping roughly 500 cu km of ice in the oceans annually.
“The contribution of both ice sheets together to sea level rise has doubled since 2009,” said Angelika Humbert from Germany’s Alfred Wegener Institute.
“To us, that’s an incredible number,” she told BBC News.
In its report to The Cryosphere journal, the AWI team does not actually calculate a sea-level rise equivalent number, but if this volume is considered to be all ice (a small part will be snow) then the contribution is likely to be on the order of just over a millimetre per year.