Greenland ice sheet climate disequilibrium and committed sea-level rise

Ice loss from the Greenland ice sheet is a major source of present-day sea-level rise (SLR). Process-based models face limitations, including imprecise atmospheric and oceanic coupling. This study presents a complementary, observation-constrained approach that resolves the ice sheet’s geometrical disequilibrium with recent (2000–2019) climate using satellite-derived bare-ice extent, tidewater discharge, and surface mass balance (SMB) data. Greenland’s current imbalance commits at least 274 ± 68 mm of global eustatic SLR, equivalent to a 59 ± 15 × 10³ km² retreat and 3.3% volume loss, regardless of future climate pathway. A perpetually high-melt state analogous to 2012 yields a commitment of 782 ± 135 mm SLR. The committed loss arises from increased mass turnover through precipitation, ice flow discharge, and especially meltwater run-off.