Two New Papers: Antarctic SMB Projections and the IMBIE Mass Balance Record

Two papers I contributed to have just been published, one led by a colleague on Antarctic surface mass balance projections and one from the IMBIE community on the mass balance of the Greenland and Antarctic ice sheets.

Diverging runoff drives uncertainty in Antarctic SMB projections

Led by Benjamin Heurgue and published in The Cryosphere, this study compares three regional climate models (MAR, RACMO and HIRHAM), all downscaling the same CESM2 simulation under the high-emission SSP5-8.5 scenario. The models agree closely on present-day Antarctic surface mass balance, yet they diverge strongly for the end of the century over the ice shelves: from near balance in RACMO to a loss of several hundred gigatonnes per year in HIRHAM, with runoff driving most of the spread. Over the grounded ice sheet, all models project an increase in SMB due to stronger snowfall.

The main message is that agreement on present-day SMB does not guarantee reliable future projections. I provided the MAR projections used in the study and contributed to the discussions on the paper.

Heurgue, B., Amory, C., Kittel, C., et al. (2026). Diverging runoff drives uncertainty in Antarctic surface mass balance projections under a high emission scenario. The Cryosphere, 20 (11), 6353-6373.

Mass balance of the Greenland and Antarctic ice sheets from the 1970s to 2023

This paper, published in Scientific Data, is a product of the IMBIE (Ice Sheet Mass Balance Inter-comparison Exercise) community, of which I am glad to be part. It combines 42 independent satellite-based estimates of ice sheet mass balance, covering Greenland from 1972 and Antarctica from 1979 to 2023. Regional climate models are used to separate the total mass change into surface mass balance and ice dynamical imbalance. Together, the two ice sheets lost about 11,300 billion tonnes of ice between 1979 and 2023, with ice dynamics accounting for 84% of the loss.

My contribution is the modelled surface mass balance from MAR.

Otosaka, I. N., Shepherd, A., Amory, C., et al. (2026). Mass balance of the Greenland and Antarctic ice sheets from the 1970s to 2023. Scientific Data, 13, 1301.