Near‐Term Future Sea‐Level Projections Supported by Extrapolation of Tide‐Gauge Observations

Abstract 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 coastal sea‐level projections. Here, we evaluate the sea‐level trend and acceleration for a global network of 222 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 Intergovernmental Panel on Climate Change Sixth Assessment Report (AR6). For 2050 relative to 2020, the observation‐based and medium‐confidence AR6 projections agree within the likely range at 96% of tide‐gauge locations. Despite larger spatial variability, the observation‐based projections are usually well below the low‐likelihood, high‐impact AR6 projections. 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.