Context: By the end of the century the Caspian Sea will be nine metres to 18 metres lower. That’s a depth considerably taller than most houses.

• The Caspian is actually a lake, the largest in the world and it is experiencing a devastating decline in its water level that is about to accelerate.

Ongoing Concern

• By the end of the century, the Caspian Sea will be nine metres to 18 metres lower. That’s a depth considerably taller than most houses.
• The Caspian’s surface is already dropping by 7 cm every year, a trend likely to increase.
• It means the lake will lose at least 25 per cent of its former size, uncovering 93,000 sq km of dry land.
• If that new land were a country, it would be the size of Portugal.

Past strides in its level

• The Caspian Sea has a history of violent rises and falls.
• In Derbent, on the Caucasus coast of Russia, submerged ancient city walls testify to how low the sea was in medieval times.
• Around 10,000 years ago, the Caspian was about 100 metres lower.
• A few thousand years before that it was about 50 metres higher than today and even over spilt into the Black Sea.

About Caspian Sea

• The Caspian Sea is the world’s largest inland body of water, variously classed as the world’s largest lake or a full-fledged sea.
• As an endorheic basin, it lies between Europe and Asia. The countries bordering the Caspian Sea: Kazakhstan, Russia, Azerbaijan, Iran and Turkmenistan.
• An endorheic basin is a drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but converges instead into lakes or swamps, permanent or seasonal that equilibrates through evaporation
• Its level is the product of how much water is flowing in from rivers, mostly the mighty Volga to the north, how much it rains and how much evaporates away.
• At the end of the century, the Volga and other northern rivers will still be there.
• However, a projected temperature rise of about 3? to 4? in the region will drive evaporation through the roof.