Sea-level contribution from Thwaites Glacier doubles in an observation-constrained ice-sheet model
Abstract
Thwaites Glacier is a major contributor to Antarctic mass loss and a key source of uncertainty in future sea-level rise. Ocean-driven melting at its grounding line drives rapid retreat, yet most models treat the transition between grounded and floating ice as a sharp boundary, neglecting kilometer-scale seawater intrusions that develop as the grounding line migrates and forms a grounding zone. Here, we show that actively-melting grounding zones are required to reproduce nearly three decades of observed retreat, thinning, and acceleration of Thwaites Glacier in a calibrated ice-sheet model, with successful reconstruction occurring only when grounding zones are represented as 2-5 km wide regions. Extending this model forward, we show that grounding-zone processes govern glacier’s detachment from stabilizing seafloor ridges, enabling unpinning as early as 2038 and producing up to 30 ± 6 mm of global mean sea-level rise by 2100 - approximately double previous projections even without additional climate warming.
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BibTeX
@article{poinelli2026sealevel,
title = {{Sea-level contribution from Thwaites Glacier doubles in an observation-constrained ice-sheet model}},
author = {Mattia Poinelli and Eric Rignot and Hélène Seroussi and Joshua Cuzzone and Tyler Pelle and Eric Larour},
journal = {Nature Communications},
year = {2026},
month = oct,
doi = {10.1038/s41467-026-77976-1},
url = {https://www.nature.com/articles/s41467-026-77976-1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Sea-level contribution from Thwaites Glacier doubles in an observation-constrained ice-sheet model
AU - Mattia Poinelli
AU - Eric Rignot
AU - Hélène Seroussi
AU - Joshua Cuzzone
AU - Tyler Pelle
AU - Eric Larour
PY - 2026
DA - 2026/10/12
JO - Nature Communications
DO - 10.1038/s41467-026-77976-1
UR - https://www.nature.com/articles/s41467-026-77976-1
AB - Thwaites Glacier is a major contributor to Antarctic mass loss and a key source of uncertainty in future sea-level rise. Ocean-driven melting at its grounding line drives rapid retreat, yet most models treat the transition between grounded and floating ice as a sharp boundary, neglecting kilometer-scale seawater intrusions that develop as the grounding line migrates and forms a grounding zone. Here, we show that actively-melting grounding zones are required to reproduce nearly three decades of observed retreat, thinning, and acceleration of Thwaites Glacier in a calibrated ice-sheet model, with successful reconstruction occurring only when grounding zones are represented as 2-5 km wide regions. Extending this model forward, we show that grounding-zone processes govern glacier’s detachment from stabilizing seafloor ridges, enabling unpinning as early as 2038 and producing up to 30 ± 6 mm of global mean sea-level rise by 2100 - approximately double previous projections even without additional climate warming.
SN - 2041-1723
ER -