Reference : Geodetic measurements reveal similarities between post–Last Glacial Maximum and prese...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Earth sciences & physical geography
Geodetic measurements reveal similarities between post–Last Glacial Maximum and present-day mass loss from the Greenland ice sheet
Knudsen, Shfaqat mailto []
Bamber, Ingo []
Bevis, Michael [Ohio State University > Geodetic Science]
van Dam, Tonie mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Engineering Research Unit >]
Bamber, Jonathan [University of Bristol > Bristol Glaciology Centre]
Wahr, John [University of Colorado at Boulder - CU > Physics and Cooperative Institute for Research in Environmental Sciences]
Willis, Michael [Cornell Univeersity > Earth and Atmospheric Sciences]
Kjaer, Kurt [University of Copenhagen > Centre for GeoGenetics, Natural History Museum of Denmark]
Wouters, Bert [Utrecht University > Institute for Marine and Atmospheric Research]
Helm, Veit [DTU Space > Geodesy]
Csatho, Beata [University at Buffalo > Geology]
Fleming, Kevin [GFZ German Research Centre for Geosciences > 11Centre for Early Warning Systems Helmholtz Centre Potsdam]
Bjork, Anders [University of Copenhagen > Centre for GeoGenetics, Natural History Museum of Denmark]
Aschwanden, Andy [University of Alaska Fairbanks > Geophysical Institute]
Knudsen, Per [Technical University of Denmark > Geodesy]
Science Advances
[en] Greenland ; Climate ; ice mass
[en] 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. Glacial isostatic adjustment (GIA) is the ongoing response of the solid Earth to ice and ocean load changes occurring since the Last Glacial Maximum (LGM; ~21 thousand years ago) and may be used to constrain the GrIS deglaciation history. We use data from the Greenland Global Positioning System network to directly measure GIA and estimate basin wide mass changes since the LGM. Unpredicted, large GIA uplift rates of +12 mm/year are found in southeast Greenland. 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. This region of concentrated soft rheology has a profound influence on reconstructing the deglaciation history of Greenland. We reevaluate the evolution of the GrIS since LGM and obtain a loss of 1.5-m sea-level equivalent from the northwest and southeast. These same sectors are dominating modern mass loss. We suggest that the present destabilization of these marine-based sectors may increase sea level for centuries to come. Our 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.

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