NASA charts the disappearance of one of the world's greatest lakes


The dramatic disappearance of the Aral Sea is graphically recorded by NASA imagery.
NASA

The Aral Sea was once the world's fourth-largest lake but now it's a dust bowl. We've known it has been disappearing for some time, thanks to Soviet-era water diversion to the arid plains of Kazakhstan, Uzbekistan, and Turkmenistan.

But the historical imagery by NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite, as compiled above, dramatically shows the retreat of the once-rich fishing grounds since 2000.

Before the 1960s water diversion project, the Syr Darya and the Amu Darya rivers fed by snowmelt, fed the Aral.

By diverting the water, agriculture flourished in the irrigation area, but at the expense of the great lake – the black line in the gif above shows its extent before the project.

In 2005, Kazakhstan built a dam between the northern and southern parts of the Aral Sea in a last-ditch effort to save some of the lake, but that accelerated the decline of the larger southern part.

NASA charts the effects.

Especially large retreats in the eastern lobe of the Southern Sea appear to have occurred between 2005 and 2009, when drought limited and then cut off the flow of the Amu Darya. Water levels then fluctuated annually between 2009 and 2014 in alternately dry and wet years. Dry conditions in 2014 caused the Southern Sea’s eastern lobe to completely dry up for the first time in modern times.

Not only has the lake's disappearance devastated once-thriving fishing communities, it has caused widespread ecological disaster in the surrounding areas.

The blowing dust from the exposed lakebed, contaminated with agricultural chemicals, became a public health hazard. The salty dust blew off the lakebed and settled onto fields, degrading the soil. Croplands had to be flushed with larger and larger volumes of river water. The loss of the moderating influence of such a large body of water made winters colder and summers hotter and drier.

  1. http://earthobservatory.nasa.gov/Features/WorldOfChange/aral_sea.php
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