Climate Adaptation for a Natural Atoll Island in the Maldives ‐ Predicting the Long‐Term Morphological Response of Coral Islands to Sea Level Rise and the Effect of Hazard Mitigation Strategies

Abstract Coral atoll islands, common in (sub)tropical oceans, consist of low‐lying accumulations of carbonate sediment produced by fringing coral reef systems and are of great socio‐economic and ecological importance. Previous studies have predicted that many atoll islands will become uninhabitable...

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Main Authors: F. E. Roelvink, G. Masselink, C. Stokes, R. T. McCall
Format: Article
Language:English
Published: Wiley 2025-04-01
Series:Earth's Future
Subjects:
Online Access:https://doi.org/10.1029/2024EF005576
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author F. E. Roelvink
G. Masselink
C. Stokes
R. T. McCall
author_facet F. E. Roelvink
G. Masselink
C. Stokes
R. T. McCall
author_sort F. E. Roelvink
collection DOAJ
description Abstract Coral atoll islands, common in (sub)tropical oceans, consist of low‐lying accumulations of carbonate sediment produced by fringing coral reef systems and are of great socio‐economic and ecological importance. Previous studies have predicted that many atoll islands will become uninhabitable before the end of this century due to sea level rise exacerbating wave‐driven flooding. However, the assumption that such islands are morphologically static has been challenged by observations and modeling that show the potential for overwashing and sediment deposition to maintain island freeboard. Reliable long‐term predictions of island change and future flood risk, essential for adaptation planning, are, however, lacking. Here, we adopt a novel, efficient approach for modeling the long‐term island response and illustrate the morphological response of an atoll island to future sea level rise and the effect of various adaptation measures. We demonstrate that wave‐driven sediment deposition increases island (beach) crest freeboard. We find that the assumption of static island morphology leads to a significant increase in the predicted frequency of future island flooding compared to morphodynamically active islands. Reef adaptation measures were shown to modify the inshore wave energy, influencing the equilibrium island crest height and therefore the long‐term morphological response of the island, while beach restoration mainly delays the island's response. Accounting for long‐term natural island dynamics, including the morphodynamic feedback from adaptation measures, offers more realistic projections of future flood risk compared to current static island model predictions. These local projections of island response can serve as decision support tools for climate adaptation.
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spelling doaj-art-eab9cd4875ee4ed39a75306022ce69372025-08-20T03:07:58ZengWileyEarth's Future2328-42772025-04-01134n/an/a10.1029/2024EF005576Climate Adaptation for a Natural Atoll Island in the Maldives ‐ Predicting the Long‐Term Morphological Response of Coral Islands to Sea Level Rise and the Effect of Hazard Mitigation StrategiesF. E. Roelvink0G. Masselink1C. Stokes2R. T. McCall3School of Biological and Marine Sciences University of Plymouth Plymouth UKSchool of Biological and Marine Sciences University of Plymouth Plymouth UKMet Office Exeter UKDeltares Delft The NetherlandsAbstract Coral atoll islands, common in (sub)tropical oceans, consist of low‐lying accumulations of carbonate sediment produced by fringing coral reef systems and are of great socio‐economic and ecological importance. Previous studies have predicted that many atoll islands will become uninhabitable before the end of this century due to sea level rise exacerbating wave‐driven flooding. However, the assumption that such islands are morphologically static has been challenged by observations and modeling that show the potential for overwashing and sediment deposition to maintain island freeboard. Reliable long‐term predictions of island change and future flood risk, essential for adaptation planning, are, however, lacking. Here, we adopt a novel, efficient approach for modeling the long‐term island response and illustrate the morphological response of an atoll island to future sea level rise and the effect of various adaptation measures. We demonstrate that wave‐driven sediment deposition increases island (beach) crest freeboard. We find that the assumption of static island morphology leads to a significant increase in the predicted frequency of future island flooding compared to morphodynamically active islands. Reef adaptation measures were shown to modify the inshore wave energy, influencing the equilibrium island crest height and therefore the long‐term morphological response of the island, while beach restoration mainly delays the island's response. Accounting for long‐term natural island dynamics, including the morphodynamic feedback from adaptation measures, offers more realistic projections of future flood risk compared to current static island model predictions. These local projections of island response can serve as decision support tools for climate adaptation.https://doi.org/10.1029/2024EF005576atoll islandssea level riseoverwashXBeach modelingclimate adaptationreef restoration
spellingShingle F. E. Roelvink
G. Masselink
C. Stokes
R. T. McCall
Climate Adaptation for a Natural Atoll Island in the Maldives ‐ Predicting the Long‐Term Morphological Response of Coral Islands to Sea Level Rise and the Effect of Hazard Mitigation Strategies
Earth's Future
atoll islands
sea level rise
overwash
XBeach modeling
climate adaptation
reef restoration
title Climate Adaptation for a Natural Atoll Island in the Maldives ‐ Predicting the Long‐Term Morphological Response of Coral Islands to Sea Level Rise and the Effect of Hazard Mitigation Strategies
title_full Climate Adaptation for a Natural Atoll Island in the Maldives ‐ Predicting the Long‐Term Morphological Response of Coral Islands to Sea Level Rise and the Effect of Hazard Mitigation Strategies
title_fullStr Climate Adaptation for a Natural Atoll Island in the Maldives ‐ Predicting the Long‐Term Morphological Response of Coral Islands to Sea Level Rise and the Effect of Hazard Mitigation Strategies
title_full_unstemmed Climate Adaptation for a Natural Atoll Island in the Maldives ‐ Predicting the Long‐Term Morphological Response of Coral Islands to Sea Level Rise and the Effect of Hazard Mitigation Strategies
title_short Climate Adaptation for a Natural Atoll Island in the Maldives ‐ Predicting the Long‐Term Morphological Response of Coral Islands to Sea Level Rise and the Effect of Hazard Mitigation Strategies
title_sort climate adaptation for a natural atoll island in the maldives predicting the long term morphological response of coral islands to sea level rise and the effect of hazard mitigation strategies
topic atoll islands
sea level rise
overwash
XBeach modeling
climate adaptation
reef restoration
url https://doi.org/10.1029/2024EF005576
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