Karadeniz'de öngörülen aşırı deniz seviyesi ve kıyı taşkınlarına odaklanarak Türkiye'nin bölgesel denizleri üzerindeki iklim değişikliği etkileri

Sea-level rise driven by climate change significantly threatens coastal regions by increasing flooding and erosion, impacting ecological, social, and economic systems. The main objective of this study is to analyze future total water levels (TWL), tidal elevations (TE), and storm surge (SS) in the regional seas of Türkiye, and project extreme sea levels (ESL) in the Black Sea under climate scenarios until 2100. This study presents the first dynamic shoreline-based modeling for the Black Sea, enhancing the spatial accuracy of flood projections. A novel contribution is the dynamic shoreline-based modeling approach, updating shoreline positions and slopes at each simulation step for both spectral wave modeling and wave runup computations. Using regional climate model (RCM) outputs from CMIP5 datasets provided by the Copernicus Climate Change Service (C3S), the methodology involved statistical analysis, spectral wave modeling (2071–2100), wave runup computations, ESL estimation, and flood mapping. Statistical analysis quantified trends and extremes in TWL, TE, and SS. Wave projections were generated using the SWAN model calibrated with regional wind data by comparing annual mean wave characteristics against ERA5 datasets. Wave runup was calculated with empirical formulas, integrating spatial slopes and wave projections for ESL determination. ESL values were propagated inland to delineate flood extents along the Black Sea coast. The results showed that extreme TWL is projected to rise up to 920 mm along the Ukrainian Sea of Azov and 440 mm along the Romanian Black Sea coast by 2100. The southwestern Azov Sea shows the highest SS rise (590 mm), while the north may see reductions up to 480 mm. The 99th percentile significant wave height is expected to rise up to 20%. Under extreme conditions, wave runup reaches 4–6 m between Zonguldak and Sinop, and exceeds 5 m near southeastern Crimea. ESL-based flood mapping shows a 640 km² increase in inundation compared to TWL-based extents under average conditions, mainly over low-lying deltas in Romania and Ukraine.