Feedbacks and timescales in the modelled transient response of debris-covered glaciers

article Feedbacks and timescales in the modelled transient response of debris-covered glaciers published yes Florian Hardmeier author James Ferguson author 05fd8d9b-bd43-11eb-8d36-f8fb1cc98040 Andreas Vieli author TiVo department Glaciers worldwide are becoming increasingly debris-covered, yet many aspects within the coupled glacier-debris system are not well-understood. While the insulating effect of continuous debris layers is well-known, the transient feedbacks with glacier dynamics are poorly understood. The main aim of this study is to better understand the complex transient glacier response and debris-induced feedbacks through numerical flow modelling. We present an improved flowline model that couples ice flow, depth-resolved debris transport, and debris cover impact on mass balance. This approach allows for a detailed examination of the dynamics of debris-covered glaciers under transient forcing conditions of climate and debris input over extended timescales. Our results indicate that low-amplitude, decade-scale variability in debris or climate forcing does not substantially impact glacier evolution. However, large debris supply events can have a sustained impact. We find that debris-covered glacier response to warming climate forcing is non-monotonic, with distinct phases of thinning, retreat, and long-term re-advance. We attribute this to a separate, longer timescale process of englacial debris transport. Additionally, feedbacks in the englacial debris trajectory and complex bed topography further amplify the non-linear pattern of retreat in the transient glacier response to warming. https://research-explorer.ista.ac.at/download/23091/23105/2026_Cryosphere_Hardmeier.pdf application/pdfno https://creativecommons.org/licenses/by/4.0/ Copernicus Publications2026 eng The Cryosphere 1994-0416 1994-042410.5194/tc-20-5365-2026 2095365-5392 Hardmeier F, Ferguson J, Vieli A. 2026. Feedbacks and timescales in the modelled transient response of debris-covered glaciers. The Cryosphere. 20(9), 5365–5392. F. Hardmeier, J. Ferguson, and A. Vieli, “Feedbacks and timescales in the modelled transient response of debris-covered glaciers,” The Cryosphere, vol. 20, no. 9. Copernicus Publications, pp. 5365–5392, 2026. Hardmeier F, Ferguson J, Vieli A. Feedbacks and timescales in the modelled transient response of debris-covered glaciers. The Cryosphere. 2026;20(9):5365-5392. doi:<a href="https://doi.org/10.5194/tc-20-5365-2026">10.5194/tc-20-5365-2026</a> F. Hardmeier, J. Ferguson, A. Vieli, The Cryosphere 20 (2026) 5365–5392. Hardmeier, Florian, et al. “Feedbacks and Timescales in the Modelled Transient Response of Debris-Covered Glaciers.” The Cryosphere, vol. 20, no. 9, Copernicus Publications, 2026, pp. 5365–92, doi:<a href="https://doi.org/10.5194/tc-20-5365-2026">10.5194/tc-20-5365-2026</a>. Hardmeier, Florian, James Ferguson, and Andreas Vieli. “Feedbacks and Timescales in the Modelled Transient Response of Debris-Covered Glaciers.” The Cryosphere. Copernicus Publications, 2026. <a href="https://doi.org/10.5194/tc-20-5365-2026">https://doi.org/10.5194/tc-20-5365-2026</a>. Hardmeier, F., Ferguson, J., & Vieli, A. (2026). Feedbacks and timescales in the modelled transient response of debris-covered glaciers. The Cryosphere. Copernicus Publications. <a href="https://doi.org/10.5194/tc-20-5365-2026">https://doi.org/10.5194/tc-20-5365-2026</a> 230912026-10-11T22:02:04Z2026-10-12T09:21:04Z