Wolff Eric W, Mulvaney Robert, Grieman Mackenzie M, Hoffmann Helene M, Humby Jack, Nehrbass-Ahles Christoph, Rhodes Rachael H, Rowell Isobel F, Sime Louise C, Fischer Hubertus, Stocker Thomas F, Landais Amaelle, Parrenin Frédéric, Steig Eric J, Dütsch Marina, Golledge Nicholas R
Department of Earth Sciences, University of Cambridge, Cambridge, UK.
British Antarctic Survey, Cambridge, UK.
Nature. 2025 Feb;638(8049):133-137. doi: 10.1038/s41586-024-08394-w. Epub 2025 Jan 29.
The fate of the West Antarctic Ice Sheet (WAIS) is the largest cause of uncertainty in long-term sea-level projections. In the last interglacial (LIG) around 125,000 years ago, data suggest that sea level was several metres higher than today, and required a significant contribution from Antarctic ice loss, with WAIS usually implicated. Antarctica and the Southern Ocean were warmer than today, by amounts comparable to those expected by 2100 under moderate to high future warming scenarios. However, direct evidence about the size of WAIS in the LIG is sparse. Here we use sea salt data from an ice core from Skytrain Ice Rise, adjacent to WAIS, to show that, during most of the LIG, the Ronne Ice Shelf was still in place, and close to its current extent. Water isotope data are consistent with a retreat of WAIS, but seem inconsistent with more dramatic model realizations in which both WAIS and the large Antarctic ice shelves were lost. This new constraint calls for a reappraisal of other elements of the LIG sea-level budget. It also weakens the observational basis that motivated model simulations projecting the highest end of projections for future rates of sea-level rise to 2300 and beyond.
西南极冰盖（WAIS）的命运是长期海平面预测中最大的不确定性因素。在约12.5万年前的末次间冰期（LIG），数据表明海平面比现在高出数米，这需要南极冰盖流失做出重大贡献，西南极冰盖通常被认为是其中的原因。南极洲和南大洋比现在更温暖，升温幅度与在未来中高变暖情景下预计到2100年时的升温幅度相当。然而，关于末次间冰期西南极冰盖规模的直接证据却很稀少。在此，我们利用来自西南极冰盖附近的斯基特兰冰脊冰芯的海盐数据，来表明在末次间冰期的大部分时间里，罗恩冰架仍然存在，且接近其当前范围。水同位素数据与西南极冰盖的退缩相一致，但似乎与一些更极端的模型模拟结果不一致，在这些模拟中，西南极冰盖和南极大型冰架都消失了。这一新的限制要求重新评估末次间冰期海平面预算的其他要素。它还削弱了那些促使模型模拟预测到2300年及以后海平面上升速度处于预测最高值的观测依据。
