Grok Image: The Aral Sea – Geoengineering Gone Awry
by Bill Chameides | July 22nd, 2009
posted by Erica Rowell (Editor)
Salt flats and beached fishing boats, like the one shown here amid desert lands that used to be the Aral Sea, stand testament to human engineering gone awry. (WikiCommons: Staecker)
Pop Quiz: How do you turn the world’s fourth largest lake into three salty lakes and a desert?
Answer: Geoengineering, small scale.
There’s a lot of talk these days about tinkering with the climate system on a global scale to counteract the effects of climate change — we call it geoengineering. And it could be that someday we’ll have to resort to such drastic measures in a future world unable to rein in greenhouse gas emissions.
But as we contemplate new geoeengineering techniques, we should not forget that we’ve been busy at geoengineering for many, many decades. The difference is the scale of the operation — not ambitious global projects, but more modest, local projects aimed at changing the environment to meet society’s needs. Examples include dams and canals. Some of these projects are considered a success (the Panama Canal perhaps?), but others have been unmitigated disasters. The Aral Sea is one such cautionary geoeengineering tale.
The Once “Fourth Largest Lake”: Then and Now
The Aral Sea, like Utah’s Great Salt Lake, exists in what is called an endorheic or closed basin: water flows into the lake but there is no exit by way of surface rivers and streams. The amount of water in the lake is determined by a balance between water inflow, water seepage, and evaporation.
Because evaporation takes water away but leaves the dissolved salts behind, the water in endorheic basins tends to be salty. How salty depends upon the load and composition of the minerals coming into the lake and the relative rates of evaporation and seepage. At the salty extreme is the Dead Sea, whose salinity is almost ten times greater than that of an ocean.
In its prime the Aral Sea spanned some 26,000 square miles of desert basin in the eastern provinces of the former Soviet Union with a salinity of about 10 grams per liter — about one-third of that found in seawater. Fresh enough to support thriving commercial fisheries.
Times have changed. The Soviet Union is no more and the Aral is located in Kazakhstan in the north and Uzbekistan in the south. (See map.) But that is not all that is different.
Today’s Aral Sea is about one-tenth of its original size and has actually become three separate bodies of water: the Small Aral Sea (in the north) and the horseshoe-shaped Large Aral Sea (in the south), which by 2000 had split into two lobes. (See this map.)
The salinity of the seas now exceeds that of seawater, the once thriving fishing industry is no more, and much of what had been a lake is now a desolate, arid landscape known as the Aral Karakum Desert.
Laden with salts, chemicals and pesticides, wind-blown dust from the exposed lakebed threatens human health. Ironically, it also endangers the crops being grown using the water that, absent human intervention, would have gone to the Aral Sea.
What Happened to the Aral Sea?
The salt flats and beached fishing boats stand as a testament to human engineering gone awry.
In the 1950s the Soviets set in motion their grand design to grow cotton and rice in the desert. Unfortunately, their rice paddy dreams sowed the seeds of a social and ecological disaster.
To pull off the greening of the desert, they built a huge canal system that tapped both of the Aral’s main tributaries, the glacially fed Amu Dar’ya and Syr Dar’ya, effectively siphoning off the Aral’s waters before they could reach the lake. (See map.)
As is so often the case, the amount of water diverted to the desert for farming steadily increased over time. By the 1980s, what fed the Aral Sea was a trickle. Much of the once magnificent lake had become a desert and that commercial fishing industry, for all intents and purposes, was history.
An Attempt to Revive the Aral Sea Through More Geoengineering
Recognizing that the greater Aral Sea was doomed, the now independent Kazakhstan built a dam in 2005, severing the northern, less polluted parts of the lake from the southern part that borders both Kazakhstan and Uzbekistan.
Since completion, water levels in the northern section have risen about four meters and there is hope that the north Aral Sea will be saved. (See related video here.)
The prognosis is not so good for the southern section of the lake — by 2020 it’s expected to be completely dry. In spite of this, measures like planting salt- and desert-tolerant plants in the former lakebed, it is hoped, will reduce dust-storm hazards and improve living conditions for the area’s 35 million inhabitants.
What’s the Fourth Largest Lake in the World Now?
In case you’re wondering: with the Aral Sea way down on the list, the fourth largest lake is now none other than our own Lake Huron. But Lake Huronites should not get too comfortable resting on their laurels — the lake’s water levels have been declining. (See also this site.) Many suspect a 1962 dredging project by the Army Corp of Engineers is at the heart of the problem.
- Aral Sea – Kazakhstan – youtube.com
- “As a Sea Rises, So Do Hopes for Fish, Jobs and Riches” – nytimes.com article (April 6, 2006) on the Aral Sea
- Dustiest Places on Earth–Dead and Dying Seas – an online textbook from Texas A&M University
- Effects of 40 Years of Irrigation on the Aral Sea – USGS images from 1964-2002 show dwindling water levels
- Aral Sea Foundation
- A graphical chronology of the shrinking of the Aral Sea
and: Aral Karakum Desert, Aral Sea, Army Corps of Engineers, desertification, geo-engineering, geoengineering, Great Salt Lake, Kazakhstan, Lake Huron, Utah, Uzbekistan