While the level of the Aral Sea has fluctuated over its existence, the most recent level drop was caused by the former Soviet Union building massive irrigation projects in the region. The severely reduced inflow subsequently caused the water level in the Aral Sea to drop. While the North Aral Sea is rising thanks to a dike, the South Aral Sea kept dropping, thus expanding the size of the desert, until 2010, when the South Aral Sea was partly reflooded. The water level of the South Aral Sea then began to drop again, however this time more severely.
The bed of the former Aral Sea in Uzbekistan in 2004
The sands of the Aralkum and the dust which originates from it contain pollutants. The desert's location on a powerful east-west airstream has resulted in pesticides in the dust being found in the blood of penguins in Antarctica. Aral dust has also been found the fields of Russia, the forests of Norway, and in the glaciers of Greenland.