Evolution of extreme sea levels in the context of climate change – ClimEx
Changes in extreme sea levels over the last century in the North Atlantic
Characterization and understanding of changes
Context and objectives
Climate is changing due to warming, and since the 1950s, many of the observed changes are unprecedented over decades to millennia (IPCC, 2021). Global mean sea level has increased by 0.20 m over the last century, which leads to larger sea level extremes and more flooding. It is then essential to investigate how (and why) the extreme sea levels are changing, in the perspective of predicting them, and adapt coastal areas to future changes. <br /><br />Extreme sea levels are impacted by any change in mean sea level, tide and storm surges. ClimEx focuses on long-term changes in tide and storm surges, which has raised little attention up to now, compared to the mean sea level.<br /><br />The scientific objectives of ClimEx are:<br /> • to characterize how extreme sea levels are changing over the last century, focusing on tide and storm surges,<br /> • to infer the physical causes behind the observed changes, using innovative methods. <br /><br />The ClimEx project focuses on the North Atlantic.
ClimEx analyses together data from different sources, as tide gauges, low-cost bottom pressure sensors, satellite altimeters and sismographs. ClimEx explores innovative data-driven methods and numerical experiments to understand the causes behind the observed sea level changes.
The ClimEx results include publications and datasets, permanently archived. Publications focus on the characterization of extreme sea level changes during the last century over the North Atlantic, a set of innovative data-driven methods to better understand the extremes, and an attribution of the physical causes behind the observed changes.
The ClimEx project opens many perspectives. Concerning the development of the low-cost sensors, the high-frequency sea level dataset obtained during the ClimEx field campaign can now be used to validate ocean and wave models, or fine scale altimetry missions. Concerning the changes, similar changes at different stations suggest large-scale drivers but it is still challenging to understand the physical causes behind the observed changes. Future numerical modeling should help to disentangle the possible drivers. Changes over the last century were analyzed, but future projections also need to be investigated. How extreme sea levels will change in the future is essential for climate change adaptation.
Publications:
1. Roustan J.-B., Pineau-Guillou L., Chapron B., Raillard N. and Reinert M. (2022). Shift of the storm surge season in Europe due to climate variability. Sci. Rep., 12, 8210.
doi.org/10.1038/s41598-022-12356-5
2. Pineau-Guillou L., Delouis J.-M. and Chapron B. (2023). Characteristics of storm surge events along the North-East Atlantic coasts. JGR: Oceans, 128, e2022JC019493.
doi.org/10.1029/2022JC019493
3. Harter L., Pineau-Guillou L. and Chapron B. (2024). Underestimation of extremes in sea level surge reconstruction. Sci. Rep. 14, 14875.
doi.org/10.1038/s41598-024-65718-6
4. Barbot S. , Pineau-Guillou L. and Delouis J.-M. (2024). Extreme storm surge events and associated dynamics in the North Atlantic. JGR: Oceans, 129, e2023JC020772.
doi.org/10.1029/2023JC020772
5. Pineau-Guillou L., & Lazure P. (2025). M2 Seasonal Variability in Northwestern Europe: Characteristics and Drivers. Geophysical Research Letters, 52, e2024GL112554.
doi.org/10.1029/2024GL112554
6. Cheynel J., Pineau-Guillou L., Lazure P. , Marcos M. and Raillard N. (2025). Regional changes in extreme storm surges revealed by tide gauge analysis. Ocean Dynamics, 75, 29.
doi.org/10.1007/s10236-025-01675-6
7. Barbot S. , Pineau-Guillou L. and Delouis J.-M. Winter storm surge event long-term variability in the North Atlantic. Journal of Geophysical Research: Oceans,130, e2024JC022204.
doi.org/10.1029/2024JC022204
8. Cheynel J. , Pineau-Guillou L. , Lazure P. , Marcos M. , Lyard F. and Raillard N. A secular sea level hindcast (1900-2015) to investigate extreme surges variability and trends in the North Atlantic. In review.
9. Pineau-Guillou L. and Lazure P. A high-frequency dataset of sea level observations from low-cost pressure sensors. Sci Data 12, 999.
doi.org/10.1038/s41597-025-05342-9
Datasets:
1. Lazure P., Pineau-Guillou L., Leizour S. (2025). ClimEx high frequency sea level observations from low-cost pressure sensors at Blancs Sablons (Le Conquet, France). SEANOE.
doi.org/10.17882/105438
2. Cheynel J., Pineau-Guillou L., Lazure P., Lyard F., Le Roux J.-F. (2025). ClimEx 1900-2015 sea level hindcast in the North Atlantic. IFREMER.
doi.org/10.12770/da6a6b5c-586f-4a70-be43-863182fb10ad
ClimEx aims to quantify and understand the evolution of extreme sea levels along North Atlantic coasts on decadal to secular time scale, with emphasis on the tide and the storm surges. Climex will detect changes in observed climate records, identify underlying external forcings, and attribute their individual and combined impacts. ClimEx will analyse together data from different sources, as tide gauges, wave pressure sensors, satellite altimeters and sismographs. Bringing together researchers from different disciplines (ocean science and mathematics), ClimEx will explore innovative data-driven methods and numerical experiments to understand the causes behind the observed sea level changes.Veuillez entrer le nom de votre établissement...
Project coordination
Lucia Pineau-Guillou (LABORATOIRE D'OCEANOGRAPHIE PHYSIQUE ET SPATIALE)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
Partnership
LOPS LABORATOIRE D'OCEANOGRAPHIE PHYSIQUE ET SPATIALE
Help of the ANR 264,978 euros
Beginning and duration of the scientific project:
December 2021
- 48 Months
