Ice dynamics will remain a primary driver of Greenland ice sheet mass loss over the next century

The mass loss of the Greenland Ice Sheet is nearly equally partitioned between a decrease in surface mass balance from enhanced surface melt and an increase in ice dynamics from the acceleration and retreat of its marine-terminating glaciers. Much uncertainty remains in the future mass loss of the Greenland Ice Sheet due to the challenges of capturing the ice dynamic response to climate change in numerical models. Here, we estimate the sea level contribution of the Greenland Ice Sheet over the 21st century using an ice-sheet wide, high-resolution, ice-ocean numerical model that includes surface mass balance forcing, thermal forcing from the ocean, and iceberg calving dynamics. The model is calibrated with ice front observations from the past eleven years to capture the recent evolution of marine-terminating glaciers. Under a business as usual scenario, we find that northwest and central west Greenland glaciers will contribute more mass loss than other regions due to ice front retreat and ice flow acceleration. By the end of century, ice discharge from marine-terminating glaciers will contribute 5020% of the total mass loss, or twice as much as previously estimated although the contribution from the surface mass balance increases towards the end of the century. Changes in ice dynamics in the Greenland Ice Sheet are projected to contribute to significantly more mass loss than previously thought, suggesting that proper calibration and accurate representation of ice-ocean interactions are critical.

Automated summary

The mass loss of the Greenland Ice Sheet is mainly attributed to surface melt and ice dynamics changes, with marine-terminating glaciers projected to contribute significantly more mass loss in the future. Numerical models show that proper calibration and representation of ice-ocean interactions are crucial for accurate predictions.