Sensitivity Of West Antarctic Ice Sheet To 2C Warming

西南极冰盖对 2C 变暖的敏感性

• 批准号: NE/X009408/1
• 负责人: Matthew Fox
• 金额: $ 57.33万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX009408%2F1
• 关键词: Sensitivity; West; Antarctic; Ice; Sheet

As our planet is warming, global mean sea level is rising. Since the year 1900 this rise in sea level has been ~ 20 cm, initially due to the expansion of water under warmer temperatures and melting of mountain glaciers. However, over recent years the melting of the large ice sheets on Greenland and Antarctica has increased significantly, and loss of land ice (glaciers and ice sheets) is now the largest contributor to global mean sea level. The polar ice sheets hold many tens of metres of sea level equivalent, but are slow to respond to enhanced greenhouse gas emissions (i.e. slower than global temperatures). With every degree of warming, society is hence facing a long-term commitment in sea level rise for centuries and millennia into the future. This is true, even if global emissions would be halted tomorrow, and future warming would be kept below 2 degrees C, the target set by the Paris agreement in 2015. The West Antarctic Ice Sheet (WAIS) holds 4.3 m of sea level equivalent and is the part of Antarctica where most mass loss is observed today. This motivated the formation of an international consortium to recover sediments from two drill sites in the Ross Sea (Antarctica) to answer the following question: 'What is the sensitivity of the WAIS to 2C warming'. This proposal presents the case how the UK community could best contribute and lead in answering this critical question by combining our unique expertise in generating combined data and modelling approaches to address three objectives: (1) What was the configuration of the WAIS during past warm periods? (2) How did the WAIS retreat and readvance in the geological past? (3) How do changes in the Antarctic landscape through time affect ice dynamics? We will use advanced laboratory methodologies to determine the chemical fingerprint of sediments and how this relates to where on the continent the sediment came from, when it was last exposed, how close to the ice sheet margin it was deposited and under what environmental conditions. By using this information in numerical models, we will overcome a longstanding limitation that the models used to predict the future are often providing contrasting results on past ice sheet configurations. We will use a hierarchy of models, from simple ice sheet models to advanced coupled ice sheet and climate models to develop a more accurate picture of past WAIS dynamics and mechanisms in relation to ocean warming, atmospheric warming, and changing topography on land, consistent with observations from ice cores and marine sediment cores.

随着地球变暖，全球平均海平面正在上升。自1900年以来，海平面上升了约20厘米，最初是由于温度升高和山区冰川融化导致的水膨胀。然而，近年来，格陵兰岛和南极洲的大冰盖融化显著增加，陆地冰（冰川和冰盖）的损失现在是全球平均海平面的最大贡献者。极地冰盖相当于海平面几十米，但对温室气体排放的增加反应缓慢（即比全球温度慢）。因此，随着每一个程度的变暖，社会都面临着未来数百年和数千年海平面上升的长期承诺。这是真的，即使全球排放明天就停止，未来的变暖将保持在2摄氏度以下，这是2015年巴黎协定设定的目标。西南极冰盖（WAIS）相当于海平面4.3米，是南极洲的一部分，今天观察到的质量损失最多。这促使一个国际财团的形成，从罗斯海（南极洲）的两个钻井现场回收沉积物，以回答以下问题：“WAIS对2C变暖的敏感性是什么？”该提案提出的情况下，英国社会如何才能最好地作出贡献，并导致在回答这个关键问题，结合我们独特的专业知识，在生成综合数据和建模方法，以解决三个目标：（1）什么是配置的WAIS在过去的温暖时期？(2)在地质历史中，WAIS是如何后退和再前进的？(3)随着时间的推移，南极地貌的变化如何影响冰的动态？我们将使用先进的实验室方法来确定沉积物的化学指纹，以及这与沉积物来自大陆的何处，最后一次暴露的时间，沉积物与冰盖边缘的距离以及环境条件的关系。通过在数值模型中使用这些信息，我们将克服一个长期存在的局限性，即用于预测未来的模型通常会提供与过去冰盖配置相反的结果。我们将使用一系列模型，从简单的冰盖模型到先进的耦合冰盖和气候模型，以更准确地了解过去WAIS与海洋变暖，大气变暖和陆地地形变化有关的动力学和机制，与冰芯和海洋沉积物芯的观测结果一致。