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易受气候变化影响的环境之一。由于海平面上升，预计到世纪中期，其中大多数将无法居住。然而，这些预测是基于相对简单的流体动力学模型，认为岛屿是固定的，而在风暴期间被过度冲刷时，岛屿可以由于沉积物沉积而垂直增生。反复的过度冲刷可以使环礁岛跟上海平面的上升。这有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，而不必建造昂贵的海岸防御设施或创伤性地搬迁到没有洪水风险的地区。人们普遍认为，过洗是环礁岛生存的关键，但需要进一步的研究，以增加我们的定量了解过洗过程，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“彻底改变我们模拟海平面上升对环礁岛的物理影响的能力，以帮助制定，为环礁岛屿社区制定和实施变革性气候变化适应战略。我们将开展地面-在三角洲水槽中进行了突破性的实验室实验，并在马尔代夫和太平洋进行了前所未有的实地测量，我们将在那里测量过洗过程及其影响。我们将使用这些独特的数据集来开发，校准和验证水文和地貌动力学数值模型。然后将使用一个创新的模型框架来评价环礁岛应对海平面上升的各种过程的作用。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.