Decay of the Greenland Ice Sheet due to surface-meltwater-induced acceleration of basal sliding

TL;DR

This study uses high-resolution simulations to show that surface-meltwater-induced basal sliding accelerates Greenland Ice Sheet decay under global warming scenarios, highlighting increased vulnerability over the 21st century.

Contribution

Develops a parameterization for meltwater-induced basal sliding acceleration and demonstrates its impact on ice sheet stability in high-resolution ice-sheet modeling.

Findings

Surface meltwater accelerates basal sliding and ice stream speeds.

Greenland Ice Sheet decay is significantly accelerated by meltwater effects.

The decay is substantial but not catastrophic within the 21st century.

Abstract

Simulations of the Greenland Ice Sheet are carried out with a high-resolution version of the ice-sheet model SICOPOLIS for several global-warming scenarios for the period 1990-2350. In particular, the impact of surface-meltwater-induced acceleration of basal sliding on the stability of the ice sheet is investigated. A parameterization for the acceleration effect is developed for which modelled and measured mass losses of the ice sheet in the early 21st century agree well. The main findings of the simulations are: (i) the ice sheet is generally very susceptible to global warming on time-scales of centuries, (ii) surface-meltwater-induced acceleration of basal sliding leads to a pronounced speed-up of ice streams and outlet glaciers, and (iii) this ice-dynamical effect accelerates the decay of the Greenland Ice Sheet as a whole significantly, but not catastrophically, in the 21st century and beyond.