How did evaporation contribute to the shrinking of the Aral Sea?

Until the 1960s, the Aral Sea maintained a stable water level because the volume of water provided by the Syr Darya and Amu Darya rivers was roughly equal to the amount lost through evaporation.12

However, beginning in the second half of the 20th century, the Soviet Union diverted these primary river sources for large-scale agricultural irrigation. As these rivers were redirected, the inflow of water to the lake dropped drastically, often reaching negligible levels by the 21st century.123

Because the lake was no longer being replenished by river flow, the ongoing natural process of evaporation caused the sea to shrink rapidly. With the water balance disrupted, the lake’s volume and surface area declined significantly, leading to the fragmentation of the sea and severe environmental consequences for the region.12