Preprints
https://doi.org/10.5194/egusphere-2025-4176
https://doi.org/10.5194/egusphere-2025-4176
23 Sep 2025
 | 23 Sep 2025

On the non-linear response of Antarctic ice shelf surface melt to warming

Marte Gé Hofsteenge, Willem Jan van de Berg, Christiaan van Dalum, Kristiina Verro, Maurice van Tiggelen, and Michiel van den Broeke

Abstract. Surface meltwater can saturate firn, form melt ponds, and trigger hydrofracturing of Antarctic ice shelves, ultimately accelerating grounded ice flow and contributing to sea level rise. Although the response of surface melt to atmospheric warming (expressed by near-surface air temperature) is known to be non-linear, the mechanisms driving this non-linearity remain poorly understood. In this study we explain the non-linear temperature-melt relationship from an energy balance perspective and assess its spatial variability across Antarctic ice shelves. We use the regional climate model RACMO2.4p1, forced by ERA5 re-analysis and two global earth system models under the SSP3-7.0 high emission scenario, to simulate contemporary and future Antarctic climate and surface mass balance until 2100. We find that the temperature dependence of net shortwave radiation is the primary driver of the non-linearity. On relatively cold ice shelves, warming increases cloud cover and snowfall, raising albedo, reducing net shortwave radiation. In contrast, on warmer ice shelves the snowmelt-albedo feedback dominates the response: warming leads to melt that reduces albedo, enhancing shortwave radiation absorption. The temperature–melt relationship also varies spatially: ice shelves in drier regions experience more melt at the same average summer temperatures than those in wetter regions, highlighting the role of snowfall in suppressing the albedo feedback. When mean summer air temperatures reach or exceed the melting point (0 °C), ice shelves becomes even more sensitive to warming. Surface temperatures can not rise above 0 °C while the atmosphere can, allowing the sensible heat and net longwave radiation to increase. At the same time, snowfall transitions to rain, amplifying the albedo feedback. Our results suggest that currently colder, drier and stable ice shelves could experience rapid increases in melt under future warming, with implications for their long-term stability.

Competing interests: At least one of the (co-)authors is a member of the editorial board of The Cryosphere. The peer-review process was guided by an independent editor, and the authors also have no other competing interests to declare.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.
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Journal article(s) based on this preprint

26 Aug 2026
On the non-linear response of Antarctic ice shelf surface melt to warming
Marte Gé Hofsteenge, Willem Jan van de Berg, Christiaan van Dalum, Kristiina Verro, Maurice van Tiggelen, and Michiel van den Broeke
The Cryosphere, 20, 4747–4766, https://doi.org/10.5194/tc-20-4747-2026,https://doi.org/10.5194/tc-20-4747-2026, 2026
Short summary
Marte Gé Hofsteenge, Willem Jan van de Berg, Christiaan van Dalum, Kristiina Verro, Maurice van Tiggelen, and Michiel van den Broeke

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2025-4176', Anonymous Referee #1, 21 Oct 2025
    • AC1: 'Reply on RC1', Marte Hofsteenge, 21 Jan 2026
  • RC2: 'Comment on egusphere-2025-4176', Anonymous Referee #2, 17 Nov 2025
    • AC2: 'Reply on RC2', Marte Hofsteenge, 21 Jan 2026

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload
ED: Reconsider after major revisions (further review by editor and referees) (22 Jan 2026) by Christian Haas
AR by Marte Hofsteenge on behalf of the Authors (28 Jan 2026)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (09 Feb 2026) by Christian Haas
RR by Anonymous Referee #1 (22 Mar 2026)
RR by Anonymous Referee #3 (22 Jul 2026)
ED: Publish subject to minor revisions (review by editor) (01 Aug 2026) by Christian Haas
AR by Marte Hofsteenge on behalf of the Authors (13 Aug 2026)  Author's response   Author's tracked changes   Manuscript 
ED: Publish as is (16 Aug 2026) by Christian Haas
AR by Marte Hofsteenge on behalf of the Authors (21 Aug 2026)

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2025-4176', Anonymous Referee #1, 21 Oct 2025
    • AC1: 'Reply on RC1', Marte Hofsteenge, 21 Jan 2026
  • RC2: 'Comment on egusphere-2025-4176', Anonymous Referee #2, 17 Nov 2025
    • AC2: 'Reply on RC2', Marte Hofsteenge, 21 Jan 2026

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload
ED: Reconsider after major revisions (further review by editor and referees) (22 Jan 2026) by Christian Haas
AR by Marte Hofsteenge on behalf of the Authors (28 Jan 2026)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (09 Feb 2026) by Christian Haas
RR by Anonymous Referee #1 (22 Mar 2026)
RR by Anonymous Referee #3 (22 Jul 2026)
ED: Publish subject to minor revisions (review by editor) (01 Aug 2026) by Christian Haas
AR by Marte Hofsteenge on behalf of the Authors (13 Aug 2026)  Author's response   Author's tracked changes   Manuscript 
ED: Publish as is (16 Aug 2026) by Christian Haas
AR by Marte Hofsteenge on behalf of the Authors (21 Aug 2026)

Journal article(s) based on this preprint

26 Aug 2026
On the non-linear response of Antarctic ice shelf surface melt to warming
Marte Gé Hofsteenge, Willem Jan van de Berg, Christiaan van Dalum, Kristiina Verro, Maurice van Tiggelen, and Michiel van den Broeke
The Cryosphere, 20, 4747–4766, https://doi.org/10.5194/tc-20-4747-2026,https://doi.org/10.5194/tc-20-4747-2026, 2026
Short summary
Marte Gé Hofsteenge, Willem Jan van de Berg, Christiaan van Dalum, Kristiina Verro, Maurice van Tiggelen, and Michiel van den Broeke

Data sets

Monthly RACMO2.4p1 data for Antarctica (11 km) forced with ERA5 (1979-2023), CESM2 (1985-2100) and MPI-ESM (1985-2100) Marte Ge Hofsteenge, Willem Jan van de Berg, Christiaan van Dalum, Kristiina Verro, Maurice van Tiggelen, Michiel van den Broeke https://doi.org/10.5281/zenodo.16902106

Marte Gé Hofsteenge, Willem Jan van de Berg, Christiaan van Dalum, Kristiina Verro, Maurice van Tiggelen, and Michiel van den Broeke

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Latest update: 04 Sep 2026
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Short summary
We use a regional climate model to study how surface melt on Antarctic ice shelves responds to air temperature changes. The relationship is strongly non-linear, mainly due to feedbacks in surface reflectivity, with other energy sources also contributing. Currently colder, drier, and more stable ice shelves will experience more melt at the same temperature than wetter ice shelves, highlighting their vulnerability to fracturing, ice shelf instability, and contributions to global sea-level rise.
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