Recent changes in surface elevation and discharge speed in outlet glacier systems along the margins of the Greenland Ice Sheet have provided examples of dramatic localized shifts in the balance of ice discharge, surface melt, and accumulation. These rapid changes are in sharp contrast to relatively slow variations in surface elevation in the interior, which have been tied to accumulation and firn compaction variations on a decadal timescale. The challenge of documenting and attempting to understand the processes involved has motivated a large collection of proposed research projects aimed at this problem. These range from expansions of ongoing efforts to new projects, and from individual investigators to consortia from a number of nations. They utilize a range of observational and modeling techniques and exploit evolving capabilities in atmospheric modeling, remote sensing for measurement of ice motion and surface conditions, and surface-based and aircraft-based measurement techniques.