499 / 2024-09-18 09:00:49

Near-term future sea-level projections supported by extrapolation of tide-gauge observations

sea level rise

Session 23 - Sea level rise: understanding, observing, and modelling

Global, regional and local sea-level projections rely on complex process-based models of the climate-ocean-cryosphere system. While extrapolation of observational data has been examined on global and regional scales, this approach has not yet been used for the additional complexities of local coastal sea-level projections. Here, we evaluate the sea level trend and acceleration for a global network of tide-gauge observations over 1970-2023, which are then extrapolated to provide local projections up to 2050 and compared with the process-based projections from the IPCC Sixth Assessment Report (AR6). For 2050 relative to 2020, the observation-based projections agree with AR6 process-based projections within the 90% uncertainty range at the majority (99%) of 237 tide gauges. Thus, the observation-based projections provide complementary perspectives of near-term local sea-level changes, and this agreement provides increased confidence in the current understanding and projections of sea-level changes over coming decades.