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1. Variable contributions of vertical land motion to sea-level change inferred at tide gauges

   https://doi.org/10.1038/s41561-026-02005-1  

   Dangendorf, Sönke; Oelsmann, Julius; Mitrovica, Jerry X; Törnqvist, Torbjörn E; Piecuch, Christopher G; Creel, Roger; Coronel, William; Thompson, Philip R; Ebinger, Cynthia; Wahl, Thomas (June 2026, Nature Geoscience)

   Vertical land motion is a key component of relative sea-level changes in coastal areas. Rates of vertical land motion can vary temporally owing to anthropogenic and natural processes. Yet, such nonlinear behaviour has not been fully accounted for in twentieth-century sea-level budgets or projections because long-term observations at relevant spatial scales are scarce. Here we infer vertical land motion at a global set of tide gauge stations by comparing their records with a probabilistic reconstruction of climate-related sea level (1900–2021) that integrates model-based estimates of sterodynamic, barystatic and inverse-barometer contributions. Differences between climate-related sea-level and tide gauge records primarily reflect vertical land motion and reveal previously unreported temporal variations linked to subsurface fluid withdrawal, as well as seismic and volcanic processes. We show that decadal fluctuations in regional relative sea-level trends can exceed those driven by climate-related processes by an order of magnitude. Consequently, vertical land motion projections based on linear extrapolations introduce systematic median sea-level projection errors of typically up to 7.6 mm yr−1 at sites influenced by seismic or volcanic activity and 5.6 mm yr−1 at the other sites. Our time-varying vertical land motion estimates constrain geophysical models of anthropogenic and volcano-tectonic crustal processes and pave the way for more robust sea-level projections at tide gauges. 

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2. Coastal Sea Level Observations Record the Twentieth-Century Enhancement of Decadal Climate Variability

   https://doi.org/10.1175/JCLI-D-22-0451.1  

   Little, Christopher M. (January 2023, Journal of Climate)

   Abstract Changes in the amplitude of decadal climate variability over the twentieth century have been noted, with most evidence derived from tropical Pacific sea surface temperature records. However, the length, spatial coverage, and stability of most instrumental records are insufficient to robustly identify such nonstationarity, or resolve its global spatial structure. Here, it is found that the long-term, stable, observing platform provided by tide gauges reveals a dramatic increase in the amplitude and spatial coherence of decadal (11–14-yr period) coastal sea level ( ζ ) variability between 1960 and 2000. During this epoch, western North American ζ was approximately out of phase with ζ in Sydney, Australia, and led northeastern U.S. ζ by approximately 1–2 years. The amplitude and timing of changes in decadal ζ variability in these regions are consistent with changes in atmospheric variability. Specifically, central equatorial Pacific wind stress and Labrador Sea heat flux are highly coherent and exhibit contemporaneous, order-of-magnitude increases in decadal power. These statistical relationships have a mechanistic underpinning: Along the western North American coastline, equatorial winds are known to drive rapidly propagating ζ signals along equatorial and coastal waveguides, while a 1–2-yr lag between Labrador Sea heat fluxes and northeastern United States ζ is consistent with a remotely forced, buoyancy-driven, mechanism. Tide gauges thus provide strong independent support for an increase in interbasin coherence on decadal time scales over the second half of the twentieth century, with implications for both the interpretation and prediction of climate and sea level variability. Significance Statement Decadal climate variability influences the frequency and severity of many natural hazards (e.g., drought), with considerable human and ecological impacts. Understanding observed changes and predicting future impacts relies upon an understanding of the physical processes and any changes in their variability and relationship over time. However, identifying such changes requires very long observational records. This paper leverages a large set of tide gauge records to show that decadal time scale coastal sea level variability increased dramatically in the second half of the twentieth century, in widely separated geographic locations. The increase was driven by a shift in the amplitude, spatial pattern, and interbasin coherence of atmospheric pressure, wind, and sea surface temperature variability. 

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3. Multi-century geological data thins the tail of observationally based extreme sea level return period curves

   https://doi.org/10.1038/s44304-024-00040-9  

   Joyse, Kristen M; Stein, Michael L; Horton, Benjamin P; Kopp, Robert E (December 2024, npj Natural Hazards)

   Estimates of extreme sea-level return periods guide flood hazard mitigation. Return period estimates calculated from tide gauge records, which are relatively short (typically less than 100 years), can fail to capture the rarest and most potentially impactful extreme events. Here, we employ a two-dimensional Poisson point process model to fuse water-level data from tide gauges with data from multi-century geologic records of extreme overwash events. Experiments with synthetic data show that including geologic data reduces the uncertainty of 1% and 0.1% average annual chance water levels by about half, relative to using tide gauge data alone. Similar uncertainty reductions occur with two case studies of geologic data (Mattapoisett Marsh, Massachusetts and Cheesequake, New Jersey) and their neighboring tide gauges (Woods Hole, Massachusetts and the Battery, New York). The analysis also reveals non-stationarity at Cheesequake and The Battery, arising from either climatic changes or changes in the fidelity of the geological record, with substantially higher 1–10% average annual chance water levels since 1900 compared to prior centuries. 

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4. Changes in the Seasonal Cycle of Storm Surge Along the Global Coastline

   https://doi.org/10.1029/2024JC022187  

   Barroso, A; Wahl, T; Enriquez, A; Morim, J; Dangendorf, S (May 2025, Journal of Geophysical Research: Oceans)

   Abstract Storm surge events are a key driver of widespread flooding, particularly when combined with astronomical tides superimposed on mean sea level (MSL). Coastal storms exhibit seasonal variability which translates into a seasonal cycle in storm surge activity. Understanding changes in the seasonal storm surge cycle is critical as both changes in the amplitude and the phase may alter the flood potential, especially when compounded with changes in the MSL cycle. Here, a comprehensive analysis of the storm surge seasonal cycle and its links to the MSL seasonal cycle is performed using tide gauge observations from a quasi‐global data set. Harmonic analysis is used to assess the mean and changing storm surge seasonal cycles over time. Extreme value analysis is applied to explore the effect of seasonal changes on storm surge return levels. We also quantify the influence of large‐scale climate modes, and we compare how the seasonality of storm surge and MSL have changed relative to each other. The peak of the storm surge cycle typically occurs during winter for tide gauges outside of tropical cyclone regions, where there is also greater variability in the phase of the storm surge cycle. The timing of the peak varied by more than a month at 21% of the tide gauges analyzed. The MSL and storm surge cycles peaked at least once within 30 days over the historic records at 74% of tide gauges. 

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5. Reconstruction of hourly coastal water levels and counterfactuals without sea level rise for impact attribution

   https://doi.org/10.5194/essd-16-1121-2024  

   Treu, Simon; Muis, Sanne; Dangendorf, Sönke; Wahl, Thomas; Oelsmann, Julius; Heinicke, Stefanie; Frieler, Katja; Mengel, Matthias (January 2024, Earth System Science Data)

   Abstract. Rising seas are a threat to human and natural systems along coastlines. The relation between global warming and sea level rise is established, but the quantification of impacts of historical sea level rise on a global scale is largely absent. To foster such quantification, here we present a reconstruction of historical hourly (1979–2015) and monthly (1900–2015) coastal water levels and a corresponding counterfactual without long-term trends in sea level. The dataset pair allows for impact attribution studies that quantify the contribution of sea level rise to observed changes in coastal systems following the definition of the Intergovernmental Panel on Climate Change (IPCC). Impacts are ultimately caused by water levels that are relative to the local land height, which makes the inclusion of vertical land motion a necessary step. Also, many impacts are driven by sub-daily extreme water levels. To capture these aspects, the factual data combine reconstructed geocentric sea level on a monthly timescale since 1900, vertical land motion since 1900 and hourly storm-tide variations since 1979. The inclusion of observation-based vertical land motion brings the trends of the combined dataset closer to tide gauge records in most cases, but outliers remain. Daily maximum water levels get in closer agreement with tide gauges through the inclusion of intra-annual ocean density variations. The counterfactual data are derived from the factual data through subtraction of the quadratic trend. The dataset is made available openly through the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) at https://doi.org/10.48364/ISIMIP.749905 (Treu et al., 2023a). 

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