Antarctic Ice Sheet dynamics over the past 4 million years (ICEBERGS)

我们需要更精确地了解气候系统的临界点，以便更好地评估未来全球变化的速度和幅度。在这里，南极冰盖的作用是至关重要的，因为它的融化可能会使全球海平面上升60米。过去两个世纪的仪器气候记录缺乏气候模式预估中经常使用的非线性阈值行为；然而，地质记录表明，在过去的这些转折点上，地球系统发生了大规模的、往往是不可逆转的变化。我希望通过过去400万年中温度、大气二氧化碳或全球海平面高于今天的这些关键转折点来研究南极洲的动力学和冰质量损失历史。这些时期分别是末次间冰期、海洋同位素第11期、中更新世过渡期和中上新世暖期。我将把重点放在冰山上，这是一个很大的未知数，尽管它们贡献了南极总冰质量损失的一半。最近从斯科舍海冰山巷及其周围回收的IODP核心材料将成为地理焦点。这是南极冰山穿过并最终融化的中心路径，在海洋沉积物中积累了冰山漂浮的碎片。这项工作将得到来自南极关键地点的进一步IODP和ODP站点的补充。如此大规模的环南极工作，包括确定冰山的地球化学来源，以前从未做过，也从未实施过基于人工智能的方法，旨在利用这些方法来处理大量数据。补充研究应进行粒度比较分析，生成尘埃指标以建立基于轨道的年代学，并确定南极大陆上冰山的地球化学来源。“冰山”项目有可能提供有关过去冰山喷发历史的时间和动态的基本见解，并更好地评估相关的全球海平面上升。首先，长期的南极冰质量损失重建也可以为气候模式校准提供急需的数据，从而影响许多科学领域。

We need a much more refined understanding of tipping points in the climate system to better assess the pace and magnitude of future global changes. Here, the role of the Antarctic Ice Sheet is crucial and heavily debated since its melting could rise global sea levels by up to 60 m. Instrumental climate records of the last two centuries lack the non-linear, threshold behavior often used in climate model projections; however, geological records indicate that large-scale and often irreversible shifts in the Earth system took place at such past tipping points. I wish to study the dynamics and ice-mass loss history of Antarctica through such critical tipping points over the past 4 million years, when either temperature, atmospheric carbon dioxide or global sea level were higher than today. Such times are the Last Interglacial, Marine Isotopic Stage 11, the Mid-Pleistocene Transition and the Mid-Pliocene Warm Period. I will focus on icebergs which are the big unknown although they contribute half of the total Antarctic ice-mass loss. Recently recovered IODP core material from and around Scotia Sea’s Iceberg Alley will be the geographic focus. This is the central pathway where Antarctic icebergs route through and finally melt down, accumulating iceberg-rafted debris in ocean sediment. This work will be complemented by further IODP and ODP sites from Antarctic key locations. Such a large-scale, circum-Antarctic work, which includes determining the iceberg source geochemically, has never been done before, nor has the Artificial Intelligence based method intended to utilize to cope with the vast amount of data, ever been implemented. Complementary studies shall conduct comparable grain-size analysis, generate dust indicators to establish the orbital-based chronology, and determine the source of icebergs on the Antarctic continent geochemically. Project ICEBERGS has the potential to provide fundamental insight into the timing and dynamics of past iceberg discharge history and to better assess associated global sea-level rise. This first, long-term Antarctic ice-mass loss reconstruction can also deliver much needed data for climate model calibration and hence impact a number of scientific fields.