Reconstructing millennial-scale ice sheet change in the western Amundsen Sea Embayment, Antarctica, using high-precision exposure dating.

如果政府要在变暖的世界中成功地规划未来，那么准确预测未来海平面上升的时间和幅度具有重要的社会和经济意义。西南极冰盖（WAIS），特别是其阿蒙森海部分，是这种预测的关键，因为它有可能非常迅速地退缩，也许只需几个世纪。我们迫切需要改进预测其未来稳定性的模型，因为锁在其中的水有可能对全球海平面上升做出重大贡献（高达1.2米）。这将对世界各地的低洼城市造成广泛破坏，包括欧洲的主要沿海和经济中心，如伦敦。有关冰盖过去大小和形状的信息对于测试和改进预测模型至关重要。然而，尽管它的重要性，了解未来的海平面上升，在阿蒙森海湾（ASE）的南极洲的建模工作目前受到阻碍的数据缺乏WAIS的历史，特别是在西部的ASE（我们知道的撤退和变薄的一般模式在东部的ASE，虽然一些细节尚不清楚）。拟议中的项目将产生一个独特的高分辨率记录冰盖变薄在过去20,000年从鲜为人知的西方ASE。我们将使用令人兴奋的表面暴露测年技术的创新，以确定冰盖厚度的微小波动，其精度比以前在南极洲达到的更高。在过去的20，000年中，WAIS的形状和大小的信息包含在南极洲表面沉积的岩石中，因为冰盖已经退缩并变薄。地表暴露年代测定法包括收集这些岩石，并测量其上表面浓缩的同位素10 Be的丰度，这是自岩石最后一次被冰覆盖以来的化学信号。因为我们计划从ASE西部今天冰面以上的高度范围收集这些信息，我们将能够知道WAIS的这一部分变薄的速度，以及变薄开始和停止的时间。除了建立WAIS这一部分的历史外，这种方法还将使我们深入了解过去十年中记录和广泛宣传的冰盖变化的重要性。例如，它们仅仅是长期变薄趋势的延续，还是最近才开始发生，如果是这样，为什么？通过比较ASE西部和东部冰川的退缩历史，我们还将了解ASE不同地区可能如何应对未来的环境变化。我们建议的一个重要部分将是进一步发展我们与使用地质数据测试和调整冰盖模型的建模人员的现有合作。我们的数据将使这些模型得到重大改进，最终有助于更准确地预测未来全球海平面上升。

Accurate prediction of when and how much sea level rise is likely to take place in the future is of great societal and economic importance if governments are to successfully plan for the future in a warming world. The West Antarctic Ice Sheet (WAIS), and particularly its Amundsen Sea sector, is key to such predictions because it has the potential to retreat very rapidly, perhaps over just a few centuries. We urgently need improvements to models that predict its future stability because the water locked inside it has the potential to make a major contribution (up to 1.2 metres) to global sea level rise. This would result in widespread damage to low-lying cities around the world, including major coastal and economic hubs in Europe, such as London. Information about the past size and shape of ice sheets is essential for testing and refining predictive models. However, despite its importance for understanding future sea level rise, modelling efforts in the Amundsen Sea Embayment (ASE) of Antarctica are currently hindered by a lack of data on the history of the WAIS, particularly in the western ASE (we know the general pattern of retreat and thinning in the eastern ASE, although some of the details are not yet clear). The proposed project will produce a unique high-resolution record of ice sheet thinning over the past 20,000 years from the poorly-known western ASE. We will use exciting innovations in the technique of surface exposure dating to determine small fluctuations in ice sheet thickness with greater precision than has previously been achieved in Antarctica. Information on the shape and size of the WAIS over the past 20,000 years is contained within rocks deposited on the surface of Antarctica as the ice sheet has retreated and thinned since that time. Surface exposure dating involves collecting such rocks and measuring the abundance of an isotope, 10Be, concentrated within their upper surfaces, which acts as a chemical signal for the length of time since the rock was last covered by ice. Because we plan to collect this information from a range of heights above today's ice surface in the western ASE, we will be able to tell how rapidly that part of WAIS has thinned, and when the thinning started and stopped. As well as establishing the history of this part of the WAIS, this approach will also give us insight into the significance of ice sheet changes recorded and widely publicised over the past decade. For example, are they simply the continuation of a long-term trend of thinning, or have they only started happening relatively recently and, if so, why? By comparing the retreat history of glaciers in the western and eastern parts of the ASE, we will also learn how different parts of the ASE are likely to respond to future environmental change.An important part of our proposal will be to further develop our existing collaborations with modellers who use geological data to test and tune their ice sheet models. Our data will permit significant improvements in these models, ultimately contributing to more accurate prediction of future global sea level rise.