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Keeping an Eye on Antarctic Ice Sheet Stability

机译：密切关注南极冰盖的稳定性

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Knowledge of how the Antarctic Ice Sheet (AIS) responded in the geologic past to warming climates will provide powerful insight into its poorly understood role in future global sea level change. Study of past natural climate changes allows us to determine the sensitivity of the AIS to higher-than-present atmospheric carbon dioxide (CO2) concentrations and global temperatures, thereby providing the opportunity to improve the skill and performance of ice sheet models used for Intergovernmental Panel on Climate Change (IPCC) future projections.Antarctic and Southern Ocean (south of 60 degrees S latitude) marine sediment records obtained over the last 50 years by seven scientific ocean drilling expeditions have revolutionized our understanding of Earth's climate system and the evolution and dynamics of the Antarctic ice sheets through the Cenozoic (0-65 million years ago). These records document an ice-free subtropical Antarctica between similar to 52 and 40 million years ago when CO2 was similar to 1,000 ppm; the initiation of continental-scale Antarctic ice sheets similar to 34 million years ago as CO2 dropped below 800 ppm; evidence for a dynamic, largely terrestrial, ice sheet driving global sea level changes of up to 40 m amplitude between 34 and 15 million years ago; and colder periods of highly dynamic, marine-based ice sheets contributing up to 20 m of global sea level rise when CO2 levels were in the range of 500-300 ppm between similar to 14 and 3 million years ago.Notwithstanding these discoveries, paleoenvironmental records obtained around Antarctica are still limited in their geographical coverage and do not provide a basis for comprehensive understanding of how different sectors of Antarctica respond to climate perturbations. Transects of drill cores spanning ice-proximal to ice-distal environments across the continental margin and at sensitive locations that have been identified by models and recent observations are needed to fully understand temporal and spatial ice volume changes that result from complex ice sheet-ocean-atmosphere interactions. These records are also critical for reconstructing equator-to-pole temperature gradients through time to better understand global climate change, interhemispheric long-distance transmission of changes through the atmosphere and ocean (teleconnections), and the amplification of climate signals in the polar regions.Future Antarctic scientific ocean drilling will remain key to obtaining records of past Antarctic Ice Sheet dynamics that can be integrated into coupled ice sheet-climate models for improved projections of sea level change. Thus, keeping an eye on ice sheet stability is critical for improving the accuracy and precision of predictions of future changes in global and regional temperatures and sea level rise.
机译：了解南极冰盖（AIS）在过去的地质学中对气候变暖的反应，将提供对其在未来全球海平面变化中作用不甚了解的强有力的见解。对过去自然气候变化的研究使我们能够确定AIS对高于当前的大气二氧化碳（CO2）浓度和全球温度的敏感性，从而为提高政府间小组使用的冰盖模型的技能和性能提供了机会关于气候变化（IPCC）的未来预测。过去七十年来，七次科学性海洋钻探探险队获得了南极和南大洋（南纬60度）海洋沉积物记录，这彻底改变了我们对地球气候系统及其演化和动力学的认识。穿过新生代（0-65百万年前）的南极冰盖。这些记录记录了一个无冰的亚热带南极洲，大约在52到4000万年前，当时的CO2接近1000 ppm。大陆规模的南极冰盖的形成类似于3400万年前，因为二氧化碳降至800 ppm以下；在34至1500万年前之间，动态的，主要是陆地的冰原驱动全球海平面变化高达40 m的振幅的证据；当二氧化碳水平在500-300 ppm的范围内（大约在14到300万年前）时，高动态的海洋冰盖在更冷的较冷时期中贡献了高达20 m的全球海平面。尽管有这些发现，但古环境记录在南极洲附近获得的地理范围仍然有限，并且没有为全面了解南极洲不同地区如何应对气候扰动提供基础。需要通过模型和最近的观测资料来确定横跨大陆边缘和敏感位置的跨冰近至冰远环境的钻芯横断面，以便充分了解由复杂的冰盖-海洋-冰雪造成的时空冰量变化。大气相互作用。这些记录对于通过时间重建赤道到极点的温度梯度，以更好地了解全球气候变化，变化通过大气和海洋的半球长距离传输（电话连接）以及极地地区的气候信号放大至关重要。未来的南极科学海洋钻探将仍然是获取过去南极冰盖动力学记录的关键，这些记录可以集成到冰盖-气候耦合模型中，以改进海平面变化的预测。因此，密切关注冰盖的稳定性对于提高全球和区域温度以及海平面上升未来变化预测的准确性和准确性至关重要。

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  • 来源
    《Oceanography》 |2019年第1期|32-47|共16页
  • 作者

    Escutia Carlota; DeConto Robert M.; Dunbar Robert; De Santis Laura; Shevenell Amelia; Naish Timothy;

  • 作者单位

    Univ Granada, Inst Andaluz Ciencias Tierra, CSIC, Granada, Spain;

    Univ Massachusetts, Dept Geosci, Amherst, MA 01003 USA;

    Stanford Univ, Dept Environm Earth Syst Sci, Stanford, CA 94305 USA;

    Ist Nazl Oceanog & Geofis Sperimentale, Trieste, Italy;

    Univ S Florida, Coll Marine Sci, St Petersburg, FL 33701 USA;

    Victoria Univ Wellington, Antarctic Res Ctr, Wellington, New Zealand;

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