Four decades of Antarctic Ice Sheet mass balance from 1979–2017

We use updated drainage inventory, ice thickness, and ice velocity data to calculate the grounding line ice discharge of 176 basins draining the Antarctic Ice Sheet from 1979 to 2017. We compare the results with a surface mass balance model to deduce the ice sheet mass balance. The total mass loss increased from 40 [Formula: see text] 9 Gt/y in 1979–1990 to 50 [Formula: see text] 14 Gt/y in 1989–2000, 166 [Formula: see text] 18 Gt/y in 1999–2009, and 252 [Formula: see text] 26 Gt/y in 2009–2017. In 2009–2017, the mass loss was dominated by the Amundsen/Bellingshausen Sea sectors, in West Antarctica (159 [Formula: see text] 8 Gt/y), Wilkes Land, in East Antarctica (51 [Formula: see text] 13 Gt/y), and West and Northeast Peninsula (42 [Formula: see text] 5 Gt/y). The contribution to sea-level rise from Antarctica averaged 3.6 [Formula: see text] 0.5 mm per decade with a cumulative 14.0 [Formula: see text] 2.0 mm since 1979, including 6.9 [Formula: see text] 0.6 mm from West Antarctica, 4.4 [Formula: see text] 0.9 mm from East Antarctica, and 2.5 [Formula: see text] 0.4 mm from the Peninsula (i.e., East Antarctica is a major participant in the mass loss). During the entire period, the mass loss concentrated in areas closest to warm, salty, subsurface, circumpolar deep water (CDW), that is, consistent with enhanced polar westerlies pushing CDW toward Antarctica to melt its floating ice shelves, destabilize the glaciers, and raise sea level.