Constraining projections of ice sheet instabilities and future sea level rise

未来海平面快速上升的最大威胁是由于不稳定和失控的冰损失造成的冰盖崩溃。到2100年，它可能导致海平面上升1米以上，淹没目前居住着1亿人的土地，并通过增加风暴和洪水风险在高海拔沿海地区造成进一步破坏。预测这种不稳定性的未来可能性以及由此产生的合理的“最坏情况”海平面变化对于充分规划海岸防御和长期基础设施（例如150年规划范围）至关重要，特别是那些罕见事件可能产生破坏性后果的基础设施（例如核电站，泰晤士河屏障，运输网络）。然而，这是非常具有挑战性的，因为自从我们开始观察冰盖以来，冰盖不稳定性还没有发生（记录太短，冰盖在最近的过去一直很稳定），它们依赖于在无法进入的区域发生的知之甚少的机制（例如冰的滑动），例如在几公里的冰下。有一个解决办法：冰盖不稳定性发生在地质学的过去，例如在14，500年前的北美（猛犸象和现代人类的时代），在340年内造成海平面上升约7米。古老的冰盖在地貌上留下了它们活动和退缩的指纹，在英国、北方和北美等地，这些指纹已经被非常详细地重建。这些过去冰盖演变的记录提供了一个未开发的数据金矿，可用于测试和改进数值模型，为未来的预测提供信息。这一概念由DeConto和Pollard（2016）证明，他们预测南极融化导致海平面上升15米，到2500年，基于300万年前的限制（上一次大气二氧化碳水平与今天一样高）。然而，这项工作缺少一个重要的部分。为了将过去的知识可靠地转化为对未来的预测，需要考虑到过去冰盖建模中最重要和最复杂的不确定性来源：气候。这需要新的统计方法和一个在统计、气候和冰盖不稳定性方面具有独特专长的人来领导其发展。这个奖学金的目标是让那个人成为我。我将领导一个跨学科的研究团队，开发和应用新的统计和基于物理的工具，以准确量化过去，现在和未来气候和冰盖演变的不确定性，从而释放地质记录的关键潜力，以限制未来冰盖的不稳定性。这将产生对未来冰盖不稳定性和由此产生的海平面变化的第一个可靠预测。它将联合和发展我的研究的三个主要方面：冰盖不稳定性，气候变化和不确定性量化的机制，建立我作为一个世界领导者在使用地质数据来约束冰盖的行为和未来的海平面变化。

The largest threat of future rapid sea level rise is from the collapse of ice sheets due to instability and runaway ice loss. It could lead to more than 1 m of sea level rise by 2100, submerging land currently home to 100 million people and causing further destruction in higher-elevation coastal regions through enhanced storm and flood risk. Predicting the future possibility of such instabilities and the resulting plausible 'worst case' sea level change is critical for adequately planning coastal defences and long term infrastructures (e.g. 150 years planning horizon), especially those for which a rare event could have devastating consequences (e.g. nuclear power plants, the Thames barrier, transport networks). Yet, this is extremely challenging, because ice sheet instabilities have not occurred since we started observing ice sheets (the record is too short and ice sheets have been stable in the recent past) and they depend on poorly understood mechanisms (e.g. sliding of ice) that occur in inaccessible areas, such as under kilometres of ice. There is a solution: ice sheet instabilities have occurred in the geological past, for example in North America, 14,500 years ago (the time of mammoths and modern humans), producing ~7 m sea level rise in 340 years. Ancient ice sheets have left fingerprints of their activity and retreat on the landscape, which have been reconstructed in great detail in places such as the UK, Northern Europe and North America. These records of past ice sheet evolution provide an untapped goldmine of data that could be used to test and improve numerical models, informing future projections. This concept was demonstrated by DeConto and Pollard (2016), who projected Antarctic melting resulting in 15 m of sea level rise by 2500 based on constraints from 3 million years ago (the last time levels of atmospheric carbon dioxide were as high as today). However, there is an important missing piece to this work. In order to reliably translate knowledge from the past into confident future projections, the most important and complex source of uncertainty in modelling past ice sheets needs to be accounted for: the climate. This requires new statistical methods and a person with a unique combination of expertise in statistics, climate and ice sheet instabilities to lead their development. The ambition for this fellowship, is to make that person me . I will lead an interdisciplinary team of researchers to develop and apply new statistical and physically-based tools to accurately quantify uncertainties in past, present and future climate and ice sheet evolution, thus unlocking the key potential of geological records to constrain future ice sheet instability. This will produce the first robust projection of future ice sheet instability and the resulting sea level change. It will unite and grow the three leading strands of my research: mechanisms of ice sheet instability, climate change, and uncertainty quantification, establishing me as a world leader in using geological data to constrain ice sheet behaviour and future sea level change.