While high temperatures were critical to the melting seen in Greenland last year, scientists say that clear blue skies also played a key role.
In a study, they found that a record number of cloud free days saw more sunlight hit the surface while snowfall was also reduced.
These conditions were due to wobbles in the fast moving jet stream air current that also trapped heat over Europe.
As a result, Greenland's ice sheet lost an estimated 600 billion tonnes.
Current climate models don't include the impact of the wandering jet stream say the authors, and may be underestimating the impact of warming.
Greenland's ice sheet is seven times the area of the UK and up to 2-3km thick in places. It stores so much frozen water that if the whole thing melted, it would raise sea levels worldwide by up to 7m.
Last December, researchers reported that the Greenland ice sheet was melting seven times faster than it had been during the 1990s.