Last updated October 10, 2018

Geodetic measurements reveal similarities between post–Last Glacial Maximum and present-day mass loss from the Greenland ice sheet

  • States that accurate quantification of the millennial-scale mass balance of the Greenland ice sheet (GrIS) and its contribution to global sea-level rise remain challenging because of sparse in situ observations in key regions
  • Uses data from the Greenland Global Positioning System network to directly measure GIA and estimate basin-wide mass changes since the LGM
  • Finds that there are unpredicted, large GIA uplift rates of +12 mm/year in southeast Greenland
  • Finds that these rates are due to low upper mantle viscosity in the region, from when Greenland passed over the Iceland hot spot about 40 million years ago
  • Finds this region of concentrated soft rheology has a profound influence on reconstructing the deglaciation history of Greenland
  • Reevaluates the evolution of the GrIS since LGM and obtains a loss of 1.5-m sea-level equivalent from the northwest and southeast
  • States these same sectors are dominating modern mass loss
  • Suggests that the present destabilization of these marine-based sectors may increase sea level for centuries to come
  • The new deglaciation history and GIA uplift estimates suggest that studies that use the Gravity Recovery and Climate Experiment satellite mission to infer present-day changes in the GrIS may have erroneously corrected for GIA and underestimated the mass loss by about 20 gigatons/year