Eco-geomorphic response of the Funafuti Atoll reef flat, central Pacific, to sea-level rise and tropical storms over 120 years (1898-2019).

This study examines eco-geomorphic changes on the exposed reef flat of Funafuti Atoll over the past 120 years to assess the relative influence of sea-level rise and storm events on reef flat and adjacent environments. Despite a documented sea-level rise of approximately 0.45 m during this period, we find no evidence of long-term structural or ecological alteration on the reef flat itself. We attribute this stability to emergent properties that may buffer against sea-level-driven impacts observed elsewhere. By contrast, significant geomorphic adjustments occurred at the reef flat margins: spur destruction on the seaward edge and increased island elevation landward. These changes reflect cyclone-induced disturbances combined with relative submergence of the reef flat. Notably, this research provides the first empirical evidence linking rising sea levels to increased atoll island elevation. Our findings suggest that future trajectories of reef flats and islands will depend on site-specific interactions among eco-geomorphic inheritance, sea-level rise rates and storm frequency. While these results are broadly applicable to emergent reef flats typical of Indo-Pacific atolls, further comparative studies across diverse reef flat types are essential to refine predictions of atoll resilience under accelerating climate change.