Greenland’s bed topography is a primary control on ice flow, grounding line migration,
calving dynamics, and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm
Atlantic water (AW) that rapidly melts and undercuts Greenland’s marine-terminating glaciers. Here we
present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice
thickness data through a mass conservation approach. A new 150 m horizontal resolution bed topography/
bathymetric map of Greenland is constructed with seamless transitions at the ice/ocean interface, yielding
major improvements over previous data sets, particularly in the marine-terminating sectors of northwest
and southeast Greenland. Our map reveals that the total sea level potential of the Greenland ice sheet
is 7.42 ± 0.05 m, which is 7 cm greater than previous estimates. Furthermore, it explains recent calving
front response of numerous outlet glaciers and reveals new pathways by which AW can access glaciers
with marine-based basins, thereby highlighting sectors of Greenland that are most vulnerable to future
oceanic forcing.