Abstract
The global acceleration of sea-level rise (SLR) during the 20th century is now established. On the local scale, this is harder to establish as several drivers of SLR play a role, which can mask the acceleration. Here, we study the rate of SLR along the coast of the Netherlands from the average of six tide gauge records covering the period 1890-2021. To isolate the effects of the wind field variations and the nodal tide from the local sea-level trend, we use four generalised additive models (GAMs) which include different predictive variables. From the sea-level trend estimates, we obtain the continuous evolution of the rate of SLR and its uncertainty over the observational period. The standard error in the estimation of the rate of SLR is reduced when we account for nodal-tide effects and is reduced further when we also account for the wind effects, meaning these provide better estimates of the rate of SLR. A part of the long-term SLR is due to wind forcing related to a strengthening and northward shift of the jet stream, but this SLR contribution decelerated over the observational period. Additionally, we detect wind-forced sea-level variability on multidecadal timescales with an amplitude of around 1 cm. Using a coherence analysis, we identify both the North Atlantic Oscillation and the Atlantic Multidecadal Variability as its drivers. Crucially, accounting for the nodal-tide and wind effects changes the estimated rate of SLR, unmasking an SLR acceleration that started in the 1960s. Our best-fitting GAM, which accounts for nodal and wind effects, yields a rate of SLR of about 1.72.21.3 mm yr-1 in 1900-1919 and 1.51.91.2 mm yr-1 in 1940-1959 compared to 2.93.52.4 mm yr-1 in 2000-2019 (where the lower and upper bounds denote the 5th and 95th percentiles). If we discount the nodal tide, wind and fluctuation effects and assume a constant rate of SLR, then the probability (p value) of finding a rate difference between 1940-1959 and 2000-2019 of at least our estimate is smaller than 1 %. Consistent with global observations and the expectations based on the physics of global warming, our results show unequivocally that SLR along the Dutch coast has accelerated since the 1960s.
| Original language | English |
|---|---|
| Pages (from-to) | 991-1007 |
| Number of pages | 17 |
| Journal | Ocean Science |
| Volume | 19 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 6 Jul 2023 |
Bibliographical note
Funding Information:Iris Keizer and Sybren Drijfhout were supported by the Netherlands Knowledge Programme on sea-level rise. Dewi Le Bars was supported by H2020 project RECEIPT (REmote Climate Effects and their Impact on European Sustainability, Policy and Trade (grant no. 820712)). Roderik van de Wal and André Jüling were supported by the Netherlands Polar Program to the Dutch Polar Climate and Cryosphere Change Consortium under file no. ALWPP.2019.003. This publication was supported by PROTECT. This project has received funding from the European Union's Horizon 2020 research and innovation programme (grant no. 869304), PROTECT contribution number 70.
Publisher Copyright:
© 2023 Iris Keizer et al.
Funding
Iris Keizer and Sybren Drijfhout were supported by the Netherlands Knowledge Programme on sea-level rise. Dewi Le Bars was supported by H2020 project RECEIPT (REmote Climate Effects and their Impact on European Sustainability, Policy and Trade (grant no. 820712)). Roderik van de Wal and André Jüling were supported by the Netherlands Polar Program to the Dutch Polar Climate and Cryosphere Change Consortium under file no. ALWPP.2019.003. This publication was supported by PROTECT. This project has received funding from the European Union's Horizon 2020 research and innovation programme (grant no. 869304), PROTECT contribution number 70.