The Aral tragedy.What used to be the world's fourth largest lake (now number seven) is drying up. A legacy of Soviet-era megaprojects, the level of the Aral Sea Aral Sea (ăr`əl), salt lake, SW Kazakhstan and NW Uzbekistan, E of the Caspian Sea in an area of interior drainage. To the north and west are the edges of the arid Ustyurt Plateau; the Kyzyl Kum desert stretches to the southeast. is now 16 metres lower than in 1960, it covers only half the area it did, and its volume has dropped by 75%. At the same time, its salt content has gone up threefold. Soviet planners decreed that the desert regions of Central Asia should be a cotton-producing area. To achieve this goal, rivers that fed the Aral Sea were diverted for irrigation irrigation, in agriculture, artificial watering of the land. Although used chiefly in regions with annual rainfall of less than 20 in. (51 cm), it is also used in wetter areas to grow certain crops, e.g., rice. . As a result, too little water now reaches the Aral Sea to replace evaporation evaporation, change of a liquid into vapor at any temperature below its boiling point. For example, water, when placed in a shallow open container exposed to air, gradually disappears, evaporating at a rate that depends on the amount of surface exposed, the humidity , and towns that were once thriving fishing ports are now as much as 50 kilometres from the shoreline. Meanwhile, the cotton harvest is declining. The smaller sea has affected the local climate so that there is now a shorter growing season growing season, period during which plant growth takes place. In temperate climates the growing season is limited by seasonal changes in temperature and is defined as the period between the last killing frost of spring and the first killing frost of autumn, at which and frequent dust storms. The salt blowing off the dry seabed has reduced the soil's fertility. |
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