Possible Clues:

• Its surface area is about 25% of what it was in 1960
• Erstwhile Asian lake
• Shrinking body of Asia
• Large ex-lake
• Lake of Central Asia now only a quarter of the area it was in 1960
• Site of sand-locked ships cited by Gore
• Lake that has lost a lot of its original volume
• Asian body of water that's now largely dried up
• Body of water greatly shrunk by 1960s Soviet irrigation
• Shrinking salt lake in Asia