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Nature:未来的南极冰层和海平面水平

摘要 : 南极冰层对海平面上升的未来贡献有可能是巨大的,但仍然存在很大不确定性,部分原因是计算方面的局限性。

南极冰层对海平面上升的未来贡献有可能是巨大的,但仍然存在很大不确定性,部分原因是计算方面的局限性。现在,Nicholas Golledge及同事提供了在气候变暖情形下对南极冰层所做的千年尺度的模拟,其结果显示,随着海洋变暖大约0.5°C和大气变暖2.0°C,南极洲大部分边缘冰架都可能会坍塌,导致冰层向海洋中加速运动。虽然在方法上仍然存在很大不确定性,但在这些模拟中,由南极冰融化造成的海平面上升到2300年在大约0.1米至3米之间,到5000年在0.4米至9米之间。所估计的海平面上升的巨大范围既反映了方法上的不确定性,也反映了温室气体潜在排放的很宽范围。

原文链接:

The multi-millennial Antarctic commitment to future sea-level rise

原文摘要:

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 century1. 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 Change3. 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.

来源: Nature 浏览次数:0

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