Preprints
https://doi.org/10.5194/egusphere-2024-232
https://doi.org/10.5194/egusphere-2024-232
28 Feb 2024
 | 28 Feb 2024

Widespread increase in discharge from West Antarctic Peninsula glaciers since 2018

Benjamin J. Davison, Anna E. Hogg, Carlos Moffat, Michael P. Meredith, and Benjamin J. Wallis

Abstract. Many glaciers on the Antarctic Peninsula have retreated and accelerated in recent decades. Here we show that there was a widespread, quasi-synchronous and sustained increase in grounding line discharge from glaciers on the west coast of the Antarctic Peninsula since 2018. Overall, west Antarctic Peninsula discharge trends increased by over a factor of three, from 0.5 Gt/y/decade during 2017 to 2020 up to 1.6 Gt/y/decade in the years following, leading to a grounding line discharge increase of 7 Gt/y (7.4 %) since 2017. The acceleration in discharge was concentrated at glaciers connected to deep, cross-shelf troughs hosting warm ocean waters, and the acceleration occurred during a period of anomalously high subsurface water temperatures on the continental shelf. Given that many of the affected glaciers have retreated over the past several decades in response to ocean warming, thereby highlighting their sensitivity to ocean forcing, we argue that the recent period of anomalously warm water was likely a key driver of the observed acceleration. However, the acceleration also occurred during a time of anomalously high atmospheric temperatures and glacier surface runoff, which could have contributed to speed-up by directly increasing basal water pressure and, by invigorating near-glacier circulation, increasing submarine melt rates. The spatial pattern of glacier acceleration therefore provides an indication of glaciers that are exposed to warm ocean water at depth and/or have active surface-to-bed hydrological connections. Both atmospheric and ocean temperatures in this region and its surroundings are likely to increase further in the coming decades, suggesting that discharge increases may continue and become more widespread.

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 preprint. The responsibility to include appropriate place names lies with the authors.
Benjamin J. Davison, Anna E. Hogg, Carlos Moffat, Michael P. Meredith, and Benjamin J. Wallis

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-232', Anonymous Referee #1, 01 Apr 2024
    • AC1: 'Reply on RC1', Benjamin Davison, 23 May 2024
  • RC2: 'Comment on egusphere-2024-232', Anonymous Referee #2, 06 Apr 2024
    • AC2: 'Reply on RC2', Benjamin Davison, 23 May 2024

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-232', Anonymous Referee #1, 01 Apr 2024
    • AC1: 'Reply on RC1', Benjamin Davison, 23 May 2024
  • RC2: 'Comment on egusphere-2024-232', Anonymous Referee #2, 06 Apr 2024
    • AC2: 'Reply on RC2', Benjamin Davison, 23 May 2024
Benjamin J. Davison, Anna E. Hogg, Carlos Moffat, Michael P. Meredith, and Benjamin J. Wallis
Benjamin J. Davison, Anna E. Hogg, Carlos Moffat, Michael P. Meredith, and Benjamin J. Wallis

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Short summary
Using a new dataset of ice motion, we observed glacier acceleration on the west coast of the Antarctic Peninsula. The speed-up began around January 2021 but some glaciers sped-up earlier or later. All of those glaciers flow into the ocean where they melt – ship-based observations show that ocean temperatures near the glaciers have been unusually warm since 2018, likely causing them to melt faster and speed-up. As the ocean warms more in future, these glaciers may accelerate again.