Sea-level change in Eastern Mediterranean, Aegean and Black seas analyzed at subregional scale of six CORDEX domains

This study examines climate change effects on storm surge residual (SS), tidal elevation (TE) and total water level (TWL) on a subregional scale at the intersection of six CORDEX domains including the Black (including the Sea of Azov), Marmara, Aegean, and Eastern Mediterranean seas. It compares the four seas through a rigorous statistical analysis of TWL and their components, SS and TE, for historical, mid-century and end-century periods until 2100. The statistical analysis involves examining percentages, correlation coefficients, trendlines, probability distributions, extreme values, and epoch-mean and epoch-max tidal indicators. Country-by-country analyses of TWL and SS are conducted along the coasts of countries bordering these seas. This study is the first to examine future TWL, SS, and TE, focusing on this subregion using a high temporal and spatial resolution dataset. Our findings reveal the Black Sea's heightened vulnerability, primarily due to SS. The maximum SS in the Black Sea increases at a rate of 22.7 mm/year and 11.6 mm/year in the mid-century and end-century periods, respectively. The Marmara Sea is characterized by the lowest incidences of TE, SS, and TWL, suggesting a lesser degree of susceptibility. The Aegean and Eastern Mediterranean seas exhibit similar impacts from SS and TE. The most critical coasts are the Azov Sea coasts (Ukrainian and Russian coasts), the northwestern coasts of the Black Sea (Ukrainian coast) and the northern coasts of the Aegean Sea (along the Greek mainland) with 4 m, 2 m and 1.5 m of 100-year return period TWL values, respectively. The Egyptian coast of the Mediterranean Sea is also critical due to its high maximum SS (1.2 m) in the end-century period. This study's datasets, sourced from the Copernicus Climate Change Service (C3S), underscore the necessity for robust coastal management strategies to mitigate the impending challenges posed by sea-level change.