Antarctic ice shelf collapse in Holocene driven by meltwater release feedbacks

Circumpolar Deep Water (CDW) inflow onto the Antarctic continental shelf is a key driver of accelerated Antarctic Ice Sheet (AIS) mass loss1-3, both presently4 and during the last deglaciation5,6. However, the mechanisms for enhanced CDW inflow and its impact to the large-scale AIS retreats are still not fully understood. Here, we provide sediment core evidence from sedimentary beryllium isotope and multi-proxy analysis, that ice shelf collapse and simultaneous inland ice sheet thinning around 9,000 years ago was associated with enhanced CDW inflow and sea level rise in Lutzow-Holm Bay (LHB), East Antarctica. A hierarchical modeling approach that combines climate7 and high-resolution ocean simulations8 suggests that freshwater discharge from adjacent sectors of the AIS to the Southern Ocean likely enhanced the regional CDW inflow into submarine troughs in LHB between 10,000 and 9,000 years ago. We propose that a series of tipping points propagated around the Antarctic margin during the last glacial termination, underscoring the importance of the feedback between meltwater input, CDW incursions onto the continental shelf, ice shelf stability, and ice sheet dynamics, alongside relative sea level rise, for both historical and future AIS changes.

绕极深层水（Circumpolar Deep Water, CDW）侵入南极大陆架，是当前4以及末次冰消期5,6时期南极冰盖（Antarctic Ice Sheet, AIS）质量加速流失的关键驱动因素1-3。然而，绕极深层水侵入增强的机制及其对南极冰盖大规模退缩的影响仍未完全明晰。本研究依托东南极吕佐夫-霍尔姆湾（Lutzow-Holm Bay, LHB）的沉积岩芯铍同位素与多指标分析证据，发现约9000年前的冰架崩解与内陆冰盖同步变薄，与该区域绕极深层水侵入增强及海平面上升存在关联。结合气候模拟7与高分辨率海洋模拟8的分层建模方法表明，约10000至9000年前，南极冰盖相邻流域向南大洋排放的淡水通量，可能促进了绕极深层水侵入吕佐夫-霍尔姆湾的海底槽谷区域。我们提出，末次冰消期期间一系列临界点在南极陆缘逐步传播，凸显了融水输入、绕极深层水入侵大陆架、冰架稳定性与冰盖动力学，以及相对海平面上升之间的反馈机制，对历史及未来南极冰盖变化均具有重要意义。