 This study investigates the changes in the KARA-C carbonate system, CS, and the factors that influence it, including strong stratification caused by river discharge, climate change, permafrost thawing, and increased carbon flow to the sea. The riverine plume is the main driver of future acidification due to an increase in carbon flow, leading to a decrease in pH and acidification. The prevalence of PCO2 values in the freshened surface layer over atmospheric carbon dioxide shows that atmospheric carbon dioxide cannot serve as the main driver for the acidification of the surface waters of the KARA-C. This article was authored by Alexander Palukin.