Natural Adaptation of Atoll Islands to Sea-Level Rise Offering Opportunities for Ongoing Human Occupation

由于地势低洼，珊瑚环礁岛被广泛认为是最容易受到气候变化影响的环境之一。预计到21世纪中叶，由于海平面上升，它们中的大多数将无法居住。然而，这些预测是基于相对简单的水动力学模型，该模型认为岛屿不能移动，而当风暴期间被洪水淹没时，由于沉积物沉积，岛屿可以垂直共生。反复的泛滥可以使环礁岛屿跟上海平面上升的步伐。这可能为岛屿社区提供机会，通过创新的适应战略延长可居住性，而不是不得不建造昂贵的海岸防御设施或以创伤的方式重新安置到没有洪水风险的地区。人们普遍认为，泛滥是环礁生存的关键，但还需要进一步的研究，以增加我们对泛滥过程的量化理解，并通过开发管理工具将增强的见解转化为实践。因此，该项目的总体目标是“提高我们模拟海平面上升对环礁岛屿实际影响的能力，以帮助为环礁岛屿社区制定、开发和实施变革性的气候变化适应战略”。我们将在三角洲水槽进行开创性的实验室实验，并在马尔代夫和太平洋进行史无前例的实地测量，在那里我们将测量淹没过程及其影响。我们将使用这些独特的数据集来开发、校准和验证水动力和地貌动力学数值模型。然后将使用一个创新的建模框架来评估环礁岛对海平面上升的反应所涉及的各种进程的作用。最后，将部署建模工具，使环礁岛社区能够实施适应战略，最大限度地增加继续居住的机会。

Due to their low-lying nature, coral atoll islands are widely acknowledged to be amongst the most vulnerable environments to climate change. Most of them are predicted to be uninhabitable by the mid-21st century because of sea-level rise. However, these forecasts are based on relatively simple hydrodynamic models that consider the islands immobile, whereas, when overwashed during storms, the islands can vertically accrete due to sediment deposition. Repeated overwash can enable atoll islands to keep up with rising sea level. This potentially provides opportunities for island communities to prolong habitability through innovative adaptation strategies, instead of having to construct expensive coastal defences or traumatically relocate to regions with no flood risk. It is generally accepted that overwash is key to atoll island survival, but further research is required to increase our quantitative understanding of overwash processes and transform the enhanced insights into practice by developing management tools. The overarching aim of this project is therefore to 'revolutionise our capability to model the physical impacts of sea-level rise on atoll islands to aid in the formulation, development and implementation of transformative climate-change adaptation strategies for atoll island communities'.We will conduct ground-breaking laboratory experiments in the Delta Flume and unprecedented field measurements in the Maldives and Pacific where we will measure overwash processes and their impacts. We will use these unique data sets to develop, calibrate and validate hydro- and morphodynamic numerical models. An innovative modelling framework will then be used to evaluate the role of the various processes involved in atoll island response to sea-level rise. Finally, the modelling tools will be deployed to enable atoll island communities to implement adaptation strategies that maximise opportunities for continued habitation.