The Impact of Climate Change on Extreme Wave Events and Its Implications for Marine Structure Design

Extreme wave events represent a primary source of structural fatigue and risk for marine and coastal infrastructure. Estimatingthe return period of 10, 100, or even 10000-year extreme events is an important statistical estimation to prevent projectfailures in any marine intervention. However, what does a 100-year extreme event mean in a climate change environment?Usually, Extreme Value Analysis (EVA) is a data-driven probabilistic fitted model, based on the assumption of stationarity.However, the fast anthropogenic impacts challenges this assumption by introducing non-stationarity into extreme wave heightrecords. This study investigates the influence of climate change on extreme wave heights in the western South Atlantic. Weperform EVA using outputs from two wave models forced by different greenhouse gas emission scenarios from the CoupledModel Intercomparison Project Phase 5 (CMIP5). Our results reveal an inhomogeneous climate change signal, projecting anintensification in the frequency and magnitude of extreme waves in certain regions, alongside a reduction in others. Despiteinherent uncertainties in climate modeling and EVA methods, these findings underscore the critical importance of integratingclimate projections into the design and risk assessment of coastal and offshore infrastructure to ensure long-term resilience.