Greene Chad A, Gardner Alex S, Schlegel Nicole-Jeanne, Fraser Alexander D
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
Australian Antarctic Program Partnership, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia.
Nature. 2022 Sep;609(7929):948-953. doi: 10.1038/s41586-022-05037-w. Epub 2022 Aug 10.
Antarctica's ice shelves help to control the flow of glacial ice as it drains into the ocean, meaning that the rate of global sea-level rise is subject to the structural integrity of these fragile, floating extensions of the ice sheet. Until now, data limitations have made it difficult to monitor the growth and retreat cycles of ice shelves on a large scale, and the full impact of recent calving-front changes on ice-shelf buttressing has not been understood. Here, by combining data from multiple optical and radar satellite sensors, we generate pan-Antarctic, spatially continuous coastlines at roughly annual resolution since 1997. We show that from 1997 to 2021, Antarctica experienced a net loss of 36,701 ± 1,465 square kilometres (1.9 per cent) of ice-shelf area that cannot be fully regained before the next series of major calving events, which are likely to occur in the next decade. Mass loss associated with ice-front retreat (5,874 ± 396 gigatonnes) has been approximately equal to mass change owing to ice-shelf thinning over the past quarter of a century (6,113 ± 452 gigatonnes), meaning that the total mass loss is nearly double that which could be measured by altimetry-based surveys alone. We model the impacts of Antarctica's recent coastline evolution in the absence of additional feedbacks, and find that calving and thinning have produced equivalent reductions in ice-shelf buttressing since 2007, and that further retreat could produce increasingly significant sea-level rise in the future.
南极洲的冰架有助于控制冰川冰流入海洋的速度，这意味着全球海平面上升的速度取决于这些脆弱的、漂浮在冰盖边缘的冰架的结构完整性。到目前为止，数据限制使得大规模监测冰架的生长和消退周期变得困难，而且近期冰架崩解前沿变化对冰架支撑作用的全面影响尚未得到了解。在这里，通过结合多个光学和雷达卫星传感器的数据，我们生成了自1997年以来大致以年度分辨率呈现的泛南极洲空间连续海岸线。我们发现，从1997年到2021年，南极洲冰架面积净损失了36701±1465平方公里（1.9%），在下一系列可能在未来十年发生的重大崩解事件之前无法完全恢复。与冰前沿后退相关的质量损失（5874±396亿吨）与过去四分之一世纪冰架变薄导致的质量变化（6113±452亿吨）大致相当，这意味着总质量损失几乎是仅通过基于测高的调查所能测量的两倍。我们模拟了在没有额外反馈的情况下南极洲近期海岸线演变的影响，发现自2007年以来，崩解和变薄对冰架支撑作用的减少程度相当，而且进一步的后退可能在未来导致越来越显著的海平面上升。
