Using inter-glacials to assess future sea-level scenarios (iGlass)

大量近海居住、基础设施和贸易的脆弱性使全球海平面上升成为全球社会关注的主要问题。例如，英国海岸线有1500亿GB的资产面临沿海洪水的风险，其中仅伦敦就有750亿GB。因此，大多数国家都制定/实施了保护计划，通常使用全球变暖情景(如政府间气候变化专门委员会发布的情景)的海平面上升估计范围，并辅之以有限地质研究的最坏情况值。UKCP09提供了关于英国海平面上升情景的最新指导，包括用于应急规划和考虑潜在适应限制(H++情景)的低概率、高影响范围的英国最大海平面上升。UKCP09强调，H++情景在下个世纪不太可能出现，但在规划更长期的未来海平面上升时，它确实带来了重大担忧。目前，H++的范围被设定为到21世纪末上升0.9-1.9米。这种不确定性范围很大(具有巨大的规划和财务影响)，而且--更关键的是--它没有可靠的统计基础。因此，重要的是要更好地了解在这些时间尺度上控制未来最大海平面上升估计的过程。这构成了这里提出的财团项目的主要动机。IGlass是一个范围广泛的跨学科项目，将结合现场数据和建模，以研究过去五个间冰期期间冰量/海平面对不同气候状态的反应，这些间冰期包括海平面明显高于现在的时期。这将确定格陵兰和西南极冰盖减少的可能性，这是对未来海平面预测的一个重要制约因素。一个关键的结果将是对未来最大海平面上升估计中可能的冰量贡献设定合理的限制。我们的项目以三个关键问题为指导：第一季度。在一系列不同的间冰期气候状态下，古海平面位置揭示了全球冰量/海平面变化的什么信息？Q2.过去间冰期的海平面上升速度是多少？考虑到不同的气候压力，这些速度与未来的变化有多大的相关性？第三季度。在政府间气候变化专门委员会(IPCC)给定的一系列气候预测情景下，考虑到冰盖的贡献，预计未来几个世纪最大海平面上升的极限是什么？这项研究将直接为英国和国外有关洪水风险管理的决策过程提供信息。在这方面，该项目得益于与英国环境局、UKCIP、英国保险业以及更广泛的全球学术和用户社区的科学家和从业人员的密切合作。

The vulnerability of extensive near-coastal habitation, infrastructure, and trade makes global sea-level rise a major global concern for society. The UK coastline, for example, has ~£150 billion of assets at risk from coastal flooding, of which with £75 billion in London alone. Consequently, most nations have developed/ implemented protection plans, which commonly use ranges of sea-level rise estimates from global warming scenarios such as those published by IPCC, supplemented by worst-case values from limited geological studies. UKCP09 provides the most up-to-date guidance on UK sea-level rise scenarios and includes a low probability, high impact range for maximum UK sea level rise for use in contingency planning and in considerations regarding the limits to potential adaptation (the H++ scenario). UKCP09 emphasises that the H++ scenario is unlikely for the next century, but it does introduce significant concerns when planning for longer-term future sea-level rise. Currently, the range for H++ is set to 0.9-1.9 m of rise by the end of the 21st century. This range of uncertainty is large (with vast planning and financial implications), and - more critically - it has no robust statistical basis. It is important, therefore, to better understand the processes controlling the maximum sea-level rise estimate for the future on these time-scales. This forms the overarching motivation for the consortium project proposed here. iGlass is a broad-ranging interdisciplinary project that will integrate field data and modelling, in order to study the response of ice volume/sea level to different climate states during the last five interglacials, which include times with significantly higher sea level than the present. This will identify the likelihood of reduced ice cover over Greenland and West Antarctica, an important constraint on future sea-level projections. A key outcome will be to place sound limits on the likely ice-volume contribution to maximum sea-level rise estimates for the future. Our project is guided by three key questions: Q1. What do palaeo-sea level positions reveal about the global ice-volume/sea-level changes during a range of different interglacial climate states? Q2. What were the rates of sea-level rise in past interglacials, and to what extent are these relevant for future change, given the different climate forcing? Q3. Under a range of given (IPCC) climate projection scenarios, what are the projected limits to maximum sea-level rise over the next few centuries when accounting for ice-sheet contributions? The research will directly inform decision-making processes regarding flood risk management in the UK and abroad. In this respect, the project benefits from the close co-operation with scientists and practitioners in the UK Environment Agency, UKCIP, the UK insurance industry, as well as the wider global academic and user communities.