Greenland Ice Sheet and sea-level response under climate change from AD 1600 to 2100

公元1600年至2100年气候变化下的格陵兰冰盖和海平面响应

• 批准号: NE/Y000129/1
• 负责人: Edward Hanna
• 金额: $ 105.28万
• 依托单位: University of Lincoln
• 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%2FY000129%2F1
• 关键词: Greenland; Ice; Sheet; sea; level

The Greenland Ice Sheet contains enough mass to raise global sea-level by seven metres. Greenland Ice Sheet mass loss arising from global warming is currently the main icy contributor to global sea-level rise and could contribute several tens of centimetres to global sea level by the year 2100, although this prediction is highly uncertain. Most recent studies show that surface mass balance (defined as net solid precipitation minus surface meltwater that runs off from the ice sheet) is the main part of 21st century Greenland Ice Sheet mass change; yet key gaps remain in our knowledge and understanding of Greenland Ice Sheet change at the multi-century timescale. Improved information on surface mass balance changes over space and time is needed to improve the reliability of computer models of ice-sheet flow and loss of ice via calving of icebergs (called ice dynamics). The present limited understanding of recent surface mass balance change resulting from the lack of constrained computer simulations, especially for time periods before the last 50 years or so, propagates through to unreliable estimates of future total mass balance (i.e. the sum of surface mass balance and ice dynamical changes) and therefore projections of sea level rise. Most current Greenland Ice Sheet surface mass balance datasets do not extend back before around 1900, while the more sophisticated surface mass balance models tend to focus on relatively short periods since 1960 due to unavoidable requirements of large amounts of reliable, complex input data (for example those relating to surface heat and energy flows between the ice sheet's surface and the atmosphere) which are typically unavailable before the 1960s. Also, estimates of the ice dynamic portion of ice-sheet mass change are based on statistical relationships of ice output with recent climatology, which is unlikely to be representative of the pre-instrumental period or the future. Therefore, bridging the major gap in the understanding of Greenland Ice Sheet-climate interactions and effect on sea-level during the large climate shifts between Little Ice Age (around 1600 to 1850) and the 20th/21st Century is urgently needed to reduce the significant uncertainty propagating through to the global sea-level contribution of Greenland Ice Sheet changes during the rest of the Twenty First Century. Our proposal combines a wide range of models, observations and scientific expertise to address this key knowledge gap.This project will produce estimates of past and future Greenland Ice Sheet surface mass balance and dynamic ice changes using cutting-edge climate and ice sheet models and datasets and mathematical evaluation of the uncertainties in these. The main aim of the proposed work is to produce a novel constrained surface and full mass balance history of the Greenland Ice Sheet from 1600 to 2021 and Greenland Ice Sheet mass balance projections to 2100, and to assess the resulting contribution to historical and future global sea-level. The reconstruction of the Greenland Ice Sheet surface mass balance back to 1600, for a period where such records are largely lacking, will quadruple the length of the existing published surface mass balance record, and form the basis of an improved understanding of the ice sheet's history and sensitivity to climate change. Our approach offers several key methodological improvements - most notably its inclusion of all the main outlet glaciers and determination of a range of most likely results - over previous attempts to forecast future changes in the Greenland Ice Sheet. We will combine our Greenland Ice Sheet surface mass balance projections with the total mass balance projections from our ice-sheet modelling work to calculate the relative contributions of surface mass balance and ice dynamics in space and time to total mass changes, and to determine their sensitivity to ongoing human-driven climate change during 1600-2100.

格陵兰冰盖包含足够的质量，可以将全球海平面提高七米。目前，全球变暖引起的格陵兰冰板群众损失是全球海平面上升的主要造成人物，但到2100年，可能会贡献数十亿厘米的全球海平面，尽管这一预测高度不确定。最近的研究表明，表面质量平衡（定义为从冰盖上脱落的净固体降水量减去表面融化）是21世纪格陵兰冰板质量变化的主要部分；然而，在多世纪时间范围内，我们对格陵兰冰盖变化的了解和理解仍然存在关键差距。需要在空间和时间上进行表面质量平衡变化的改进信息，以提高冰片流量的计算机模型和通过产犊冰山的损失（称为冰动力学）。目前，由于缺乏约束计算机模拟而产生的对最近的表面质量平衡变化的有限理解，尤其是在过去50年左右之前的时间段中，传播到对未来总质量平衡的不可靠估计（即表面质量平衡和冰层动态变化的总和），因此海平面上升的投影。当前的格陵兰冰盖表面质量平衡数据集在1900年左右之前并未延伸，而更复杂的表面质量平衡模型往往专注于自1960年以来相对较短的时间，这是因为不可避免的大量可靠，复杂的输入数据的要求（例如，与冰盖表面和大气之间的表面热量和能量流有关的，这是在1960年代典型地避免的。同样，冰期质量变化的冰动态部分的估计基于冰产量与最近气候的统计关系，这不可能代表乐队前时期或未来。因此，迫切需要桥接对格陵兰冰片气候气候相互作用的理解以及对海平面的影响以及对海平面的影响，在少量冰河时期（左右1600年至1850年左右）和20/21世纪之间的巨大气候变化中，迫切需要迫切需要减少大量不确定性的不确定性，从而使绿地冰板的全球海平面贡献在绿地冰板上的贡献范围内的全球级别的贡献。我们的建议结合了广泛的模型，观察和科学专业知识来解决这一关键知识差距。该项目将使用最先进的气候和冰盖模型，数据集以及对不确定性的数学评估来估算过去和未来的格陵兰冰板表面质量平衡和动态冰的变化。拟议工作的主要目的是生产新颖的限制表面和全面的质量平衡历史，从1600年到2021年，以及格陵兰冰块质量平衡预测到2100，并评估对历史和未来全球海平面的贡献。在很大程度上缺乏此类记录的时期，格陵兰冰块表面质量平衡的重建将使现有已发表的表面质量平衡记录的长度四倍，并构成对冰盖历史的理解和对气候变化的敏感性的基础。我们的方法提供了几种关键的方法论改进 - 最值得注意的是，它包括所有主要的出口冰川，并确定一系列最有可能的结果 - 比以前的尝试预测格陵兰冰盖未来变化的尝试。我们将将格陵兰冰板表面质量平衡投影与冰原建模工作中的总质量平衡投影相结合，以计算时空质量平衡和冰层动态的相对贡献，以确定它们对1600-2100期间人类驱动的气候变化的敏感性。