The multi-millennial Antarctic commitment to future sea-level rise
The multi-millennial Antarctic commitment to future sea-level rise
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DOI：
10.1038/nature15706
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发表时间：
2015-10-15
期刊：
影响因子：
64.8
通讯作者：
Gasson, E. G. W.
中科院分区：
文献类型：
--
作者：
Golledge, N. R.;Kowalewski, D. E.;Gasson, E. G. W.
预计到本世纪末，大气变暖将使全球平均地表温度比工业化前的数值增加0.3至4.8摄氏度(1)。如果人为排放继续不加控制，到2300年，全球变暖幅度可能达到8-10摄氏度。2)。在这种变暖的情况下，大冰盖对海平面上升的贡献很难量化，因为冰盖的平衡-响应时间尺度比大气或海洋的时间更长。在这里，我们使用冰盖/冰架耦合模型来表明，如果大气变暖超过目前的1.5至2摄氏度，南极主要冰架的崩溃将触发南极冰盖百年至千年尺度的反应，其中增强的粘性流动对海平面上升产生长期承诺(不可阻挡的贡献)。我们的模拟代表了当今南极冰盖系统对政府间气候变化专门委员会第五次评估报告(3)中四个具有代表性的集中路径(RCP)的海洋和气候变化的响应。我们发现，只有将温室气体排放量限制在RCP 2.6的水平，才能防止南极冰层的大量融化。更高排放的情景会导致南极的冰层消失，到2300年，海平面将上升0.6-3米。我们的结果表明，未来几十年的温室气体排放将强烈影响南极冰盖对全球海平面的长期贡献。
Atmospheric warming is projected to increase global mean surface temperatures by 0.3 to 4.8 degrees Celsius above pre-industrial values by the end of this century(1). If anthropogenic emissions continue unchecked, the warming increase may reach 8-10 degrees Celsius by 2300 (ref. 2). The contribution that large ice sheets will make to sea-level rise under such warming scenarios is difficult to quantify because the equilibrium-response timescale of ice sheets is longer than those of the atmosphere or ocean. Here we use a coupled ice-sheet/ice-shelf model to show that if atmospheric warming exceeds 1.5 to 2 degrees Celsius above present, collapse of the major Antarctic ice shelves triggers a centennial-to millennial-scale response of the Antarctic ice sheet in which enhanced viscous flow produces a long-term commitment (an unstoppable contribution) to sea-level rise. Our simulations represent the response of the present-day Antarctic ice-sheet system to the oceanic and climatic changes of four representative concentration pathways (RCPs) from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change(3). We find that substantial Antarctic ice loss can be prevented only by limiting greenhouse gas emissions to RCP 2.6 levels. Higher-emissions scenarios lead to ice loss from Antarctic that will raise sea level by 0.6-3 metres by the year 2300. Our results imply that greenhouse gas emissions in the next few decades will strongly influence the long-term contribution of the Antarctic ice sheet to global sea level.