This paper describes the relationship between sea levels and climate based on the links between sea-level variations and river runoff. During the final late Pleistocene and postglacial periods, the Caspian Sea fluctuated between regression and transgression stages. The Black Sea experienced fluctuations as well, but these were mainly controlled by the world ocean due to water exchange through the Bosporus Strait. Sometimes, the Caspian Sea overflowed into the Black Sea through the Manych Strait, and they periodically coalesced. Change in the level of both seas could be interpreted as responses to the regional-scale water budget (the balance between inflow and...