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<p>Circumpolar Deep Water inflow onto Antarctica’s continental shelves is a key driver of accelerated Antarctic Ice Sheet mass loss, both presently and during the last deglaciation. However, the mechanisms driving enhanced inflow and the resultant impact on large-scale ice-sheet retreat events are still not fully understood. Here we address this topic using marine sediment cores from Lützow–Holm Bay, East Antarctica, through analyses of sedimentary beryllium isotopes and complementary proxies. These records, when compared to inland mountain outcrop records, show that ice-shelf collapse and simultaneous inland ice-sheet thinning ~9,000 years ago were associated with enhanced Circumpolar Deep Water inflow and sea-level rise. A hierarchical modelling approach that combines climate and high-resolution ocean simulations suggests that freshwater discharge from adjacent Antarctic sectors into the Southern Ocean probably enhanced the regional inflow into submarine troughs in Lützow–Holm Bay between 10,000 and 9,000 years ago. We propose a feedback loop whereby meltwater from rapidly retreating Antarctic sectors since the Last Glacial Maximum enhanced stratification and Circumpolar Deep Water incursions onto adjacent shelves. Alongside relative sea-level rise, this meltwater feedback triggers further ice-shelf instability and enhances dynamic inland ice discharge, highlighting a mechanism relevant to future Antarctic Ice Sheet changes.</p>

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Antarctic ice-shelf collapse in Holocene driven by meltwater release feedbacks

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年11月7日

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  • Yusuke Suganuma,
  • Takuya Itaki,
  • Yuki Haneda,
  • Kazuya Kusahara,
  • Takashi Obase,
  • Takeshige Ishiwa,
  • Takayuki Omori,
  • Minoru Ikehara,
  • Robert McKay,
  • Osamu Seki,
  • Daisuke Hirano,
  • Masakazu Fujii,
  • Yuji Kato,
  • Atsuko Amano,
  • Yuki Tokuda,
  • Hokuto Iwatani,
  • Yoshiaki Suzuki,
  • Motohiro Hirabayashi,
  • Hiroyuki Matsuzaki,
  • Takeyasu Yamagata,
  • Masao Iwai,
  • Kota Katsuki,
  • Francisco J. Jimenez-Espejo,
  • Hiroki Matsui,
  • Koji Seike,
  • Moto Kawamata,
  • Naohisa Nishida,
  • Masato Ito,
  • Shin Sugiyama,
  • Jun’ichi Okuno,
  • Takanobu Sawagaki,
  • Ayako Abe-Ouchi,
  • Shigeru Aoki,
  • Hideki Miura

摘要

Circumpolar Deep Water inflow onto Antarctica’s continental shelves is a key driver of accelerated Antarctic Ice Sheet mass loss, both presently and during the last deglaciation. However, the mechanisms driving enhanced inflow and the resultant impact on large-scale ice-sheet retreat events are still not fully understood. Here we address this topic using marine sediment cores from Lützow–Holm Bay, East Antarctica, through analyses of sedimentary beryllium isotopes and complementary proxies. These records, when compared to inland mountain outcrop records, show that ice-shelf collapse and simultaneous inland ice-sheet thinning ~9,000 years ago were associated with enhanced Circumpolar Deep Water inflow and sea-level rise. A hierarchical modelling approach that combines climate and high-resolution ocean simulations suggests that freshwater discharge from adjacent Antarctic sectors into the Southern Ocean probably enhanced the regional inflow into submarine troughs in Lützow–Holm Bay between 10,000 and 9,000 years ago. We propose a feedback loop whereby meltwater from rapidly retreating Antarctic sectors since the Last Glacial Maximum enhanced stratification and Circumpolar Deep Water incursions onto adjacent shelves. Alongside relative sea-level rise, this meltwater feedback triggers further ice-shelf instability and enhances dynamic inland ice discharge, highlighting a mechanism relevant to future Antarctic Ice Sheet changes.