Global dataset of storm surges and extreme sea levels for 1950–2024 based on the ERA5 climate reanalysis

Abstract. Extreme sea levels, generated by storm surges and high tides, can cause coastal flooding and erosion. Global datasets have been instrumental in mapping extreme sea levels and associated societal risks. Harnessing the backward extension of the ERA5 reanalysis, we present a dataset containing timeseries of tides and storm surges based on a global hydrodynamic model covering the period 1950–2024. This is an extension of a previously published dataset that covered a shorter period (1979–2018). Using this dataset, we estimate extreme sea levels globally. Validation shows good agreement between observed and modelled extreme sea levels, with the level of agreement for the extended dataset being very similar to that of the previously published dataset. The extended 75-year dataset allows for a more robust estimation of return periods, often resulting in smaller uncertainties than its 40-year precursor. This underscores the necessity for long timeseries and the strength of long-term modelling enabled by the ERA5 reanalysis extension. The present dataset can be used for assessing flood risk, climate variability and climate changes.