Greenland ice sheet climate disequilibrium and
committed sea-level rise
Jason E. Box, Alun Hubbard, David B. Bahr, William T.
Colgan, Xavier Fettweis, Kenneth D. Mankoff, Adrien Wehrlé, Brice Noël, Michiel
R. van den Broeke, Bert Wouters, Anders A. Bjørk & Robert S. Fausto
Nature Climate Change (2022)
https://www.nature.com/articles/s41558-022-01441-2
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. (…)
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