Wednesday, October 1, 2014

Sea change: Satellite photos show world's fourth-largest lake disappearing

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The disappearing Aral Sea as seen from space. (NASA)
The disappearing Aral Sea as seen from space. (NASA)
The Aral Sea, once the fourth-largest lake in the world, is nearly gone.
Satellite images released by NASA this week show half of the inland lake that spans the Kazakhstan-Uzbekistan border in Central Asia are almost totally dry.
"For the first time in modern history, the eastern basin of the South Aral Sea has completely dried," NASA said in a release.
The shrinking began in the 1960s, NASA reported, when the former Soviet Union started diverting the Aral Sea's snowmelt-fed water from the Syr Darya and Amu Darya rivers to irrigate the desert farms of Kazakhstan, Uzbekistan, and Turkmenistan.
The first satellite image, taken in 2000, shows the lake split in two, creating the Northern and Southern Aral seas. A 2005 emergency dam project by Kazakhstan's government to save the northern part, followed by a four-year drought, expedited the southern sea's disappearance. The most recent image, taken in August, shows a dry lakebed where the Southern Aral Sea used to be.
The loss of water has wreaked havoc on the local community and climate, NASA notes:
As the lake dried up, fisheries and the communities that depended on them collapsed. The increasingly salty water became polluted with fertilizer and pesticides. 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.

According to Philip Micklin, geographer emeritus at Western Michigan University and an Aral Sea expert, there has been significantly less rain and snow this year in the distant Pamir Mountains, greatly reducing water flow to the Amu Darya.
In 2003, NASA scientists warned that "complete desiccation" of the sea "could happen in as few as 15 years."
Looks like their prediction is right on schedule.

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