The influence of inter-annual temperature variability on the Greenland ice sheet

• Main Authors: Lauritzen, M., Aðalgeirsdóttir, G., Rathmann, N., Grinsted, A., Noël, B., Hvidberg, C.
• Format: Conference Object
• Language: English
• Published: 2023
• Subjects: Greenland; Ice Sheet
• Online Access: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5021604

Uncertainties in the projected contribution of the Greenland ice sheet to future sea level rise mainly depend on uncertainties in the initial state of the present-day ice sheet. A previous study showed that including the inter-annual climate variability in the forcing of a simplified ice sheet model leads to an increased mass loss rate, but the effect on the Greenland ice sheet is poorly known. Here we quantify the influence of inter-annual variability on mass loss from the Greenland ice sheet using the PISM model. We construct an ensemble of climate-forcing fields that accounts for inter-annual variability in temperature using reanalysis data products from RACMO and NOAA-CIRES. We investigate the Greenland ice sheet geometry's steady state and future evolution. We find that the steady-state ice sheet volume decreases by 0.24-0.38% when forced with a varying temperature forcing compared to a constant temperature forcing, equivalent to 21.7±5.0 mm of sea level rise (SLE). The northern basins are particularly sensitive with a change in volume of 1.2-0.9%. The response to abrupt warming is 0.03-0.21 mm SLE higher per year depending on climate scenario. Our results emphasize the importance of including temperature variability in projections of future mass loss.