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Environmental problems of Northern Eurasia
The Aral Sea
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and History to the 20th Century >>>
Introduction
The Aral Sea is one of Central Asia's youngest inland water bodies, probably first
appearing in the late Pleistocene, fts closed endoreic drainage basin is dominated by two
of the largest rivers in Central Asia, the Amudarya and Syrdarya, which rise in the
mountains to the south and east and flow across the deserts of the Turanian plain to feed
the Aral Sea. Following a history of human use of these water resources that dates back
more than 3000 years, the late 20th century has been marked by an abrupt acceleration in
water offtakes. Intensive development of irrigated agriculture since the 1950s in the then
Central Asian republics of the USSR resulted in a dramatic decline in the volume of water
entering the sea from its two major tributaries, fn 1960, the Aral Sea was the fourth
largest lake in the world, but since that time it has lost two-thirds of its volume, its
surface area has been halved, its water level has dropped by more than 16m and its
salinity has increased to reach that of sea water.
These dramatic changes have had far-reaching effects, both on- and off-site. The Aral
Sea's fishing industry has completely ceased to function as most of its native organisms
have died out, and the Amudarya and Syrdarya deltas have been transformed due to the lack
of water, affecting flora, fauna, and soils. The receding sea has had local effects on
climate, and the exposed sea bed has become a major new source of saline aerosols that
contaminate surrounding agricultural land. The irrigated cropland itself has been subject
to problems of salinization and waterlogging due to poor management with consequent
negative effects on crop yields. Drainage water from these schemes is highly saline and
contaminated by high concentrations of agrochemical residues which have been linked to
poor human health in the region. The development of irrigation has not been the only cause
of desertification in the Aral Sea basin, however. Widespread grazing pressures,
technological developments, such as construction and drilling activities, and excessive
exploitation of woody shrubs for fuel wood have also contributed to the degradation of the
region.
This ecological demise of the Aral Sea and its drainage basin is often cited as one of
the foremost examples of modern human-induced environmental degradation (Micklin, 1988;
UNEP, 1992a, b; Glazovsky, 1995a; UNDP, 1995). After a brief review of the Aral Sea prior
to the 20th century, this chapter focuses largely on the last fifty years, a period during
which dramatic changes have been recorded in its physical geography.
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