Stability of interior North Greenland – an assessment from GPS and satellite data

The mass loss from the Greenland ice sheet has increased over the last two decades, and is now a major contributor to the global mean sea level rise. While the interior of the Greenland ice sheet has remained relatively stable, the mass loss from the ice sheet margins have spread to the north and since 2007 propagated into interior Greenland. We present here an assessment of the interior stability in North Greenland over the last three decades using GPS data, remote sensing data, and climate model output. We compile GPS survey data from interior ice core sites in North Greenland at GRIP (1992-1996), NorthGRIP (1996-2001), NEEM (2007-2015), and EastGRIP (2015-2022), and compare with surface mass balance estimates, and remote sensing observations to assess changes over the last decades. While the surface elevation has remained relatively stable at the northern ice divide sites, an inferred northward migration of the ice divide in Northwest Greenland observed in 2007-2015 coincided with the onset of thinning along the ice margin in the Baffin Bay area. The surface elevation near the summit of the Greenland ice sheet lowered slightly over the last 30 years, during a period of widespread thinning along the western margin. The observations are discussed in relation to regional changes in surface mass balance and the dynamical response to mass loss at the ice margin.