In the Northern Hemisphere, ~1500 glaciers, accounting for 28% of glacierized area outside the Greenland Ice Sheet, terminate in the ocean. Glacier mass loss at their ice-ocean interface, known as frontal ablation, has not yet been comprehensively quantified. Here, we estimate decadal frontal ablation from measurements of ice discharge and terminus position change from 2000 to 2020. We bias-correct and cross-validate estimates and uncertainties using independent sources. Frontal ablation of marine-terminating glaciers contributed an average of 44.47鈥壜扁6.23鈥塆t鈥塧鈭1 of ice to the ocean from 2000 to 2010, and 51.98鈥壜扁4.62鈥塆t鈥塧鈭1 from 2010 to 2020. Ice discharge from 2000 to 2020 was equivalent to 2.10鈥壜扁0.22鈥塵m of sea-level rise and comprised approximately 79% of frontal ablation, with the remainder from terminus retreat. Near-coastal areas most impacted include Austfonna, Svalbard, and central Severnaya Zemlya, the Russian Arctic, and a few Alaskan fjords.