Global warming is predicted to have a profound impact on the Greenland Ice Sheet (GrIS) and its contribution to future sea-level rise. The GrIS has seen dramatic changes over the last two decades and mass loss has been accelerating, owing to a combination of increased runoff and discharge of ice across the grounding line. The acceleration of glaciers has been reported as pervasive and spreading with time. Prominent is the significant mass change of the southeast and northwest margins associated with glacier speed-up and dynamic thinning. It is unknown, however, whether the extensively documented glacier speed-ups are a response to recent external forcing and the start of a long-term trend in increasing mass loss, or related to internal variability in the ice sheet-climate system that occurs over a range of timescales. Here, we report multi-decadal observations of ice mass change from northwestern Greenland, using stereoscopic coverage by aerial photographs recorded in 1985, and subsequent comparative surface elevation data from ICESat (Ice, Cloud and land Elevation Satellite) and ATM (Airborne Topographic Mapper) supplemented with measurements from GPS and the Gravity Recovery and Climate Experiment (GRACE) satellite gravity mission, launched in March, 2002. The GRACE results provide a direct measure of mass loss, while the GPS data are used to monitor crustal uplift caused by ice mass loss close to the GPS sites.