Li et al. (2025) Damage intensity increases ice mass loss from Thwaites Glacier, Antarctica

Identification

• Journal: ˜The œcryosphere
• Year: 2025
• Date: 2025-10-07
• Authors: Yanjun Li, Violaine Coulon, Javier Blasco, Gang Qiao, Qinghua Yang, Frank Pattyn
• DOI: 10.5194/tc-19-4373-2025

Research Groups

• School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
• Laboratoire de Glaciologie, Université libre de Bruxelles, Brussels, Belgium
• College of Surveying and Geo-informatics, Tongji University, Shanghai, China

Short Summary

This study incorporates ice damage processes into an ice-sheet model for the Thwaites Glacier basin, demonstrating that explicitly accounting for ice damage significantly increases projected ice mass loss, more than doubling it by 2300 compared to simulations that neglect damage.

Objective

• To evaluate and calibrate an ice-sheet model, incorporating ice damage, using satellite-based observations of present-day mass-change rates in the Thwaites Glacier basin.
• To explore the sensitivity of glacier retreat and mass loss in the Thwaites Glacier basin to increased ice damage intensity over multidecadal–centennial timescales.

Study Configuration

• Spatial Scale: Thwaites Glacier (TG) basin, West Antarctica (2.1 × 10^5 km^2), with simulations performed at a 2 km spatial resolution.
• Temporal Scale: Historical period (1990–2020) for model calibration and validation; future projections (2020–2300) under constant present-day atmospheric and oceanic conditions.

Methodology and Data

• Models used:
  • Kori-ULB ice-sheet model: A vertically integrated, thermomechanical finite difference model combining shallow-ice approximation with shallow-shelf approximation (hybrid model).
  • Continuum Damage Mechanics (CDM) model (Sun et al., 2017): Coupled with Kori-ULB, it establishes a direct link between ice damage (scalar variable D, 0 to 1) and ice viscosity reduction through Glen's flow law. Damage is determined by local crevasse formation (surface and basal, based on zero-stress assumption) and advection by ice flow.
  • PICO model (Reese et al., 2018): Used to estimate basal melting underneath floating ice shelves.
• Data sources:
  • Satellite observations:
    • Ice geometry: BedMachine v2 (Morlighem et al., 2020).
    • Ice velocity: MEaSUREs InSAR-Based Antarctica Ice Velocity Map, Version 2 (Rignot et al., 2017).
    • Crevasse distributions: Landsat-8 satellite images (December 2020).
    • Grounding line position: Gardner et al. (2018).
    • Ice mass change rates: Bevan et al. (2023), Shepherd et al. (2019).
  • Climate data:
    • Surface mass balance (SMB) and air temperature: Polar regional climate model MARv3.11 (Kittel et al., 2021).
    • Ocean temperature and salinity: Schmidtko et al. (2014).

Main Results

• Historical Period (1990–2020):
  • Explicitly representing ice damage significantly improves the model's ability to capture observed ice mass change in the Thwaites Glacier basin. Group 1 simulations (calibrated with damage) yielded a mean net mass balance of −26.5 Gt/a, comparable to satellite observations (−46.1 ± 7.2 Gt/a over 1992–2017), while the control model without damage underestimated it (1.2 Gt/a).
  • Group 1 simulations predicted an ice mass loss of 0.16 to 0.31 cm sea-level equivalent (SLE), with a mean of 0.24 ± 0.04 cm SLE, consistent with satellite-derived estimates (0.24 ± 0.08 cm over 1992–2017).
  • Grounding line retreat in Group 1 simulations ranged from 6 to 14 km (0.2–0.5 km/a) along the central flowline, aligning with observed rates (0.3–0.7 km/a).
  • The incorporation of ice damage led to a notable increase in simulated ice velocity, with Group 1 simulations providing a reasonable representation compared to observations.
• Future Projections (2020–2300):
  • Accounting for ice damage results in significantly higher ice velocity, reduced upstream ice thickness, accelerated grounding-line retreat, and greater ice mass loss compared to simulations neglecting damage.
  • By 2300, Group 1 simulations projected a mean ice mass loss of 5.5 ± 3.3 cm SLE, which is 5 times higher than control simulations (1 cm) and more than twice that of experiments with an artificially corrected initial state (2 cm).
  • In extreme damage scenarios (Group 2 extreme), ice mass loss could reach an average of 7.1 ± 2.8 cm SLE by 2100 (7 times higher than the Group 1 mean), with grounding line retreat up to 128 km inland from its 2020 position within 80 years.
  • Damage, primarily confined to the floating ice shelf, was found to significantly affect upstream grounded ice, with the potential to trigger substantial grounding-line retreat driven by marine ice-sheet instability mechanisms.

Contributions

• This study presents the first prognostic application of a continuum damage mechanics model to a real-world glacier (Thwaites Glacier basin) to assess the long-term (multidecadal–centennial) impacts of ice damage on ice sheet dynamics and mass loss.
• It demonstrates that explicitly representing ice damage processes in ice-sheet models is crucial for accurately capturing observed historical mass loss and significantly improves future projections of ice loss and sea-level rise, predicting more than double the mass loss by 2300 compared to models without damage.
• The research highlights a positive feedback mechanism between damage processes and ice-shelf weakening in the Thwaites Glacier basin, leading to accelerated grounding-line retreat and increased ice velocity.
• The findings suggest that ice damage could be a key driver of Thwaites Glacier's ice loss, offering an alternative or complementary explanation to previous hypotheses.

Funding

• Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (no. SML2022SP401)
• National Natural Science Fund of China (nos. 42406242, 42276249, and 42394131)
• Fundamental Research Funds for the Central Universities, Sun Yat-sen University (no. 24qnpy013)
• European Union, Horizon Europe Funding Programme for research and innovation, under grant agreement no. 101060452 (OCEAN ICE project)
• HiRISE (NWP GROOT, Netherlands, under grant agreement no. OCENW.GROOT.2019.091)
• Fonds de la Recherche Scientifique de Belgique (F.R.S.-FNRS) (Postdoctoral Researcher Fellowship for Violaine Coulon, and computational resources under grant no. 2.5020.11)

Citation

@article{Li2025Damage,
  author = {Li, Yanjun and Coulon, Violaine and Blasco, Javier and Qiao, Gang and Yang, Qinghua and Pattyn, Frank},
  title = {Damage intensity increases ice mass loss from Thwaites Glacier, Antarctica},
  journal = {˜The œcryosphere},
  year = {2025},
  doi = {10.5194/tc-19-4373-2025},
  url = {https://doi.org/10.5194/tc-19-4373-2025}
}