Greenland ice sheet climate disequilibrium and committed sea-level rise

• Main Authors: Box, J. E. (Jason E.), Hubbard, A. (Alun), Bahr, D. B. (David B.), Colgan, W. T. (William T.), Fettweis, X. (Xavier), Mankoff, K. D. (Kenneth D.), Wehrlé, A. (Adrien), Noël, B. (Brice), van den Broeke, M. R. (Michiel R.), Wouters, B. (Bert), Bjørk, A. A. (Anders A.), Fausto, R. S. (Robert S.)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Nature 2022
• Subjects: Climate-change impacts; Cryospheric science; Greenland; Ice Sheet
• Online Access: http://urn.fi/urn:nbn:fi-fe2023062760510

Abstract Ice loss from the Greenland ice sheet is one of the largest sources of contemporary sea-level rise (SLR). While process-based models place timescales on Greenland’s deglaciation, their confidence is obscured by model shortcomings including imprecise atmospheric and oceanic couplings. Here, we present a complementary approach resolving ice sheet disequilibrium with climate constrained by satellite-derived bare-ice extent, tidewater sector ice flow discharge and surface mass balance data. We find that Greenland ice imbalance with the recent (2000–2019) climate commits at least 274 ± 68 mm SLR from 59 ± 15 × 10³ km² ice retreat, equivalent to 3.3 ± 0.9% volume loss, regardless of twenty-first-century climate pathways. This is a result of increasing mass turnover from precipitation, ice flow discharge and meltwater run-off. The high-melt year of 2012 applied in perpetuity yields an ice loss commitment of 782 ± 135 mm SLR, serving as an ominous prognosis for Greenland’s trajectory through a twenty-first century of warming.