Greenland's ice sheet has more than doubled its contribution to sea level increases in the last seven years.
Glaciers are thinning at a dangerous rate and melting ice is pouring into the sea far faster than previously realised.
The environmental group Greenpeace has sent independent scientists on an expedition to Greenland to investigate the reasons behind the rapid loss of ice.
They found warm subtropical waters in the fjords and glaciers moving towards the sea at the alarming speed of up to 38 metres a day.
Al Jazeera's Tim Friend reports.