Climate change impact on the freshwater balance of quasi-closed lagoons in the North-Western Black Sea coast

Abstract

We studied the impact of regional climate changes that have occurred and are expected in the near future on the freshwater balance of quasi-closed lagoons in the North-Western Black Sea region. These lagoons do not have a permanent connection with the sea but are episodically connected to it by artificial channels, straits, or other hydraulic facilities. We used the value of the deficit in their annual freshwater balance as an indicator of vulnerability to climate change for each lagoon. The changes in the multi-year averages of climatic parameters in the North-Western Black Sea region, which determine the components of the water balance and its annual deficit in lagoons, were assessed by observations at hydrometeorological sites and outcomes of the EURO-CORDEX Project for the RCP4.5 and RCP8.5 scenarios. We have found that regional climate changes are resulting in the increasing deficit of annual freshwater balance for all quasi-closed lagoons in the North-Western Black Sea region. Also, climate change can result in excessive shallowing, salinization, and even the complete disappearance of some lagoons due to the lack of or insufficient water exchange with the sea. HIGHLIGHTS The annual mean temperature is significantly changing in the 21st century.; Annual mean evaporation from lagoons in 2021–2050 compared to 1961–1990 will increase by 29–56%.; Kuialnytskyi Liman will be most vulnerable to regional climate changes and can dry up completely.; The hydro-ecological regime of quasi-closed lagoons will worsen due to water shortage.;

Keywords

• climate change
• freshwater balance
• quasi-closed lagoons
• north-western black sea coast
• water shortage