No abstract

The predominant responses to rising sea levels are in situ adaptations. However, increasing rates of sea-level rise will render ex situ adaptations—in the form of relocations—inevitable in some low-lying coastal zones. Particularly small island states like the Maldives face this significant adaptation challenge. Here, government action is necessary to move vulnerable communities out of flood-prone areas. Yet, little empirical knowledge exists about the governance of relocations. While the literature often highlights risks and benefits of relocations, it remains unclear how governments organized relocations and what drove relocation policy. Therefore, we examined Maldivian relocation policies from 1968 to 2018 to explain government support of relocations. For this, we used a qualitative research design and extended the multiple streams approach with the theoretical lens of historical institutionalism. To gather data, we conducted semi-structured interviews (n = 23) with relocation policy experts and locals affected by relocations. Interview data was complemented with a desk review of relevant laws, historical records, and policy documents. We find 29 completed and 25 failed cases of relocations in the 50-year period. Key drivers of relocation policies are focusing events, socioeconomic development, and institutionalized island autonomy. We find that relocations were predominantly initiated as means to facilitate economic development, not as a response to rising seas or coastal risk. With current rapid economic development and strengthened democratic institutions, relocations are not considered as a policy option anymore. We conclude that implementing relocations proactively will face significant barriers in the future, which highlights the urgency of successful in situ adaptations in the Maldives.

The Maldives, with one of the lowest average land elevations above present-day mean sea level, is among the world regions that will be the most impacted by mean sea-level rise and marine extreme events induced by climate change. Yet, the lack of regional and local information on marine drivers is a major drawback that coastal decision-makers face to anticipate the impacts of climate change along the Maldivian coastlines. In this study we focus on wind-waves, the main driver of extremes causing coastal flooding in the region. We dynamically downscale large-scale fields from global wave models, providing a valuable source of climate information along the coastlines with spatial resolution down to 500 m. This dataset serves to characterise the wave climate around the Maldives, with applications in regional development and land reclamation, and is also an essential input for local flood hazard modelling. We illustrate this with a case study of HA Hoarafushi, an atoll island where local topo-bathymetry is available. This island is exposed to the highest incoming waves in the archipelago and recently saw development of an airport island on its reef via land reclamation. Regional waves are propagated toward the shoreline using a phase-resolving model and coastal inundation is simulated under different mean sea-level rise conditions of up to 1 m above present-day mean sea level. The results are represented as risk maps with different hazard levels gathering inundation depth and speed, providing a clear evidence of the impacts of the sea level rise combined with extreme wave events.