Closing Greenland's Mass Balance: Frontal Ablation of Every Greenlandic Glacier From 2000 to 2020

In Greenland, 87% of the glacierized area terminates in the ocean, but mass lost at the ice-ocean interface, or frontal ablation, has not yet been fully quantified. Using measurements and models we calculate frontal ablation of Greenland's 213 outlet and 537 peripheral glaciers and find a total frontal ablation of 481.8 +/- 24.0 for 2000-2010 and 510.2 +/- 18.6 Gt a(-1) for 2010-2020. Ice discharge accounted for similar to 90% of frontal ablation during both periods, while mass loss due to terminus retreat comprised the remainder. Only 16 glaciers were responsible for the majority (>50%) of frontal ablation from 2010 to 2020. These estimates, along with the climatic-basal balance, allow for a more complete accounting of Greenland Ice Sheet and peripheral glacier mass balance. In total, Greenland accounted for similar to 90% of Northern Hemisphere frontal ablation for 2000-2010 and 2010-2020.