Projected Changes in Extreme Waves in the Eastern Mediterranean

Abstract

This study evaluates future changes in the mean and extreme wave climate of the Eastern Mediterranean using high-resolution simulations from the SWAN wave model forced by regional climate projections under the RCP4.5 and RCP8.5 emission scenarios. Wave climate characteristics are assessed for a historical reference period (1970–2005) and two future periods, the near future (2021–2060) and the mid-future (2061–2100), with a focus on the Aegean Sea and the Levantine Basin. The results indicate that changes in extreme wave conditions are substantially more pronounced than those in mean wave climate and exhibit strong spatial and scenario dependence. In the near future, mean significant wave heights increase by approximately 4% in the southern Aegean Sea under both scenarios, while remaining largely unchanged across the Levantine Basin. Extreme wave heights show localized increases in the Aegean Sea, whereas no significant change is detected over most of the Levantine Basin. In contrast, during the mid-future period, extreme wave heights and storm activity decrease markedly across the Levantine Basin, with reductions exceeding 20% under the RCP8.5 scenario. Regional extreme value analysis based on the Generalized Extreme Value (GEV) distribution reveals that the RCP8.5 scenario produces both the largest increase (up to 24% in the central Aegean Sea) and the strongest decrease (up to -21% in the central Levantine Basin) in 100-year return period significant wave heights relative to historical conditions. These contrasting responses highlight the heightened sensitivity of extreme wave conditions to emission pathways. The findings emphasize the importance of accounting for multiple climate scenarios when assessing future design wave conditions and coastal risks, and provide valuable guidance for coastal and offshore engineering applications in the Eastern Mediterranean.