Tetiaroa diachronic geomorphology 1955 -2023 Monitoring the shoreline and vegetation cover of tropical atoll in the climate change context

The Tetiaroa atoll is virtually free of anthropogenic pressure, making it a textbook case for observing the impact of climate change on the pristine coral atolls of French Polynesia. A geospatial databasedating back to 1955 was used to map and analyze erosion and accretion phenomena on the atoll's motu (Tahitian name for islets). Its diachronic analysis documents two types of motu: those with a coralline base, which experience minimal movement over time, and the sandy motu which, on the contrary, exhibit significant dynamics linked to strong swells and storms. While we cannot yet link the observed dynamics to climate change and rising sea levels, these results will help us better understand the future impacts of extreme climatic events on Polynesian atolls.