Rapid glacier retreat rates observed in West Antarctica

• Published in: Nature Geoscience
• Main Authors: Milillo, P., Rignot, E., Rizzoli, P., Scheuchl, B., Mouginot, J., Bueso-Bello, J. L., Prats-Iraola, P., Dini, L.
• Other Authors: Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: [SDU]Sciences of the Universe [physics]; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Amundsen Sea; Pope Glacier; West Antarctica; Antarc*; Antarctica; Ice Shelf
• Online Access: https://insu.hal.science/insu-03706398; https://doi.org/10.1038/s41561-021-00877-z

International audience The Pope, Smith and Kohler glaciers, in the Amundsen Sea Embayment of West Antarctica, have experienced enhanced ocean-induced ice-shelf melt, glacier acceleration, ice thinning and grounding-line retreat in the past 30 years. Here we present observations of the grounding-line retreat of these glaciers since 2014 using a constellation of interferometric radar satellites combined with precision surface elevation data. We find that the grounding lines develop spatially variable, kilometre-scale, tidally induced migration zones. After correction for tidal effects, we detect a sustained pattern of retreat coincident with high melt rates of ungrounded ice, marked by episodes of more rapid retreat. In 2017, Pope Glacier retreated 3.5 km in 3.6 months, or 11.7 km yr -1 . In 2016-2018, Smith West retreated at 2 km yr -1 and Kohler at 1.3 km yr -1 . While the retreat slowed in 2018-2020, these retreat rates are faster than anticipated by numerical models on yearly timescales. We hypothesize that the rapid retreat is caused by unrepresented, vigorous ice-ocean interactions acting within newly formed cavities at the ice-ocean boundary.