From "An improved mass budget for the Greenland ice sheet," Ellyn M. Enderlin et al, Geophysical Research Letters Volume 41, Issue 3, pages 866–872, 16 February 2014.
In the graph below, the black line is overall ice mass lost in Greenland; the blue line is loss to due to ice discharge from marine-terminating outlet glaciers; and the red line is loss due to surface melting and runoff.
Over the course of last decade, surface melting and runoff moved to dominating over discharge. The authors write, "...84% of the increase in mass loss after 2009 was due to increased surface runoff. These observations support recent model projections that surface mass balance, rather than ice dynamics, will dominate the ice sheet’s contribution to 21st century sea level rise."