Potential implications of sea-level rise in Türkiye and its vicinity

Abstract

In the last century, the sea-level rise has accelerated due to anthropogenic climate change. With the growing population, the consequences of climate change have become more adverse. As in the rest of the world, the population pressure is high on the Turkish Coasts, where 45 million people live in. Türkiye, which has a long shoreline with 8333 km covered with seas on three sides will be affected adversely by the consequences of accelerated sea-level rise (e.g. flooding, salt intrusion, erosion, etc.). In addition to physical hazards, also socio-economic losses will have consequences. The purpose of this study is to determine the potential implications of the sea-level rise on Turkish coasts. For this purpose, the monthly sea-level data in the Turkish Seas (the Black Sea, the Marmara Sea, the Aegean Sea, and the Mediterranean Sea) are received from the Permanent Service for Mean Sea Level. However, some tide gauge stations have data gaps and insufficient data for determining long-term sea-level change. Therefore, cubic interpolation was applied to eliminate the data gaps, also the tide gauge station data in the same sea are combined to create a longer time series of sea-level change. Thus, the mean sea-level rise rates in the Black Sea, the Marmara, the Aegean, and the Mediterranean Sea are calculated at 5,31 mm/yr in 1874-2018, 8,79 mm/yr in 1984-2009, 0,844 mm/yr in 1969-2019, 0,8455mm/yr in 1923-2019, respectively. It is determined that sea-level rise has accelerated in recent decades. The accelerated sea-level rise causes the increasing frequency and intensity of disaster floods, inundations, coastal erosion, landslides, saltwater intrusion, and even storm surges. The main economic activities in this region are tourism, agriculture, fishing, port, and industry sectors. In Turkey, the coastal low-lying delta areas (i.e. Cukurova, Bafra, Carsamba, Meric, Goksu, etc.) are important in agricultural production. Especially one-third of Samsun is covered with agricultural lands its agricultural contribution to the economy is approximately $1 billion. Thanks to their long sandy beaches, the Mediterranean and the Aegean are among the destinations that attract a lot of international tourists and play an important role in the development of the region locally and nationally. Another popular destination for international tourists is Istanbul with its natural beauty, rich culture, and historical places. Hence, the socio-economic factors on the Turkish coast were examined. The contribution of the coastal region is estimated at two-thirds of the Turkish Gross Domestic Product (GDP): the Marmara, the Aegean, the Mediterranean, and the Black Sea coastal regions' contributions are 44.5%, 8.3%, 8.4%, and %4.7 respectively. As a result, these economically active regions are essential to be protected against sea-level rise. In this study, adaptation strategies have been determined for the protection of coastal areas from the destructive consequences of sea-level rise. In addition, the adaptation costs for agricultural areas (Bafra and Carsamba) in Samsun, and the sandy beaches are also examined.