Home – Home – Jornals – Geography and Natural Resources 2025 number S6

Process-based estimates of the hydrological consequences of the natural and anthropogenic components of climate change in the Selenga River basin were obtained based on the ECOMAG hydrological model and data from the CMIP6 ensemble of Earth system models. The aim of the study was to determine the impact of anthropogenic climate change on the river runoff formation of during the long low-water period of 1996-2017 and to provide forecast estimates for the near future of the 21st century. For this purpose, calculations were carried out using a physically-based model of runoff formation, previously verified against observational data, using two implementations of Earth system models: considering only the natural oscillations of the climate system and external impacts of natural origin, and considering the impact of anthropogenic activity, expressed in an increase in greenhouse gas emissions, including according to SSP scenarios for the future period. Warming in the summer period of 1996-2017 led to an increase in total evaporation, which, together with a decrease in the amount of precipitation and an increase in runoff losses due to infiltration, led to a long-term low water content of the Selenga. Under natural climatic conditions, the annual runoff of the Selenga in 1996-2017 should have been 28 % greater, including the spring flood runoff by 10 % and the summer-autumn runoff by 30 %. In the near future, on average by 2040, under scenarios SSP2-4.5 and SSP5-8.5, a decrease in the annual runoff of the Selenga by 9-25 % is likely, especially in the summer-autumn period.