The Caspian region, like the Aral, is very flat. The Volga River is the main source of water entering the Caspian Sea. Since 1977, the Caspian Sea has risen 2 meters (approximately 6.5 feet) due to increased rainfall and decreased evaporation. A two-meter sea level rise in a flat region is quite profound.

There are valuable oil resources in and around the Caspian Sea. The oil rigs are being flooded and questions of mineral rights are arising. Treaties that have been pain-stakingly hammered out are being invalidated by changes in sea level. A system of Holland-type dikes are going into place in an attempt to contain the rising waters. Oil pollution, due to the flooding of oil wells, is a major problem in the Caspian region.