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

广泛的沿海居住、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的一个主要关切。例如，英国海岸线有约1500亿英镑的资产面临沿海洪水的风险，其中仅伦敦就有750亿英镑。因此，大多数国家都制定/实施了保护计划，通常使用IPCC发布的全球变暖情景中的海平面上升估计值，并辅以有限的地质研究中的最坏情况值。UKCP 09提供了关于联合王国海平面上升情景的最新指导意见，包括联合王国海平面最大上升的低概率、高影响范围，供应急规划和考虑潜在适应的限度（H++情景）使用。UKCP 09强调，H++情景在下一个世纪不太可能出现，但在规划未来较长期海平面上升时，它确实引起了重大关切。目前，H++的范围设定为到21世纪世纪末上升0.9-1.9米。这种不确定性的范围很大（具有巨大的规划和财务影响），更重要的是，它没有可靠的统计基础。因此，重要的是要更好地了解这些时间尺度上控制未来最大海平面上升估计的过程。这就是本文所提议的联合体项目的主要动机。iGlass是一个范围广泛的跨学科项目，将整合实地数据和建模，以研究冰量/海平面对过去五次间冰期不同气候状态的反应，其中包括海平面明显高于现在的时期。这将确定格陵兰岛和南极洲西部冰盖减少的可能性，这是对未来海平面预测的一个重要限制。一个关键的成果将是对冰量可能对未来最大海平面上升估计的贡献设定合理的限制。我们的项目由三个关键问题指导：Q1。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？Q2.在过去的间冰期，海平面上升的速率是多少？在不同的气候强迫下，这些与未来变化的相关程度如何？Q3.在一系列给定的（IPCC）气候预测情景下，考虑到冰盖的贡献，未来几个世纪最大海平面上升的预测极限是什么？该研究将直接为英国和国外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署、UKCIP、英国保险业以及更广泛的全球学术界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.