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It is thus important to adapt agricultural management (including crop types) to the ecological conditions. Growing crops unsuited to the climate conditions, for example, could have harmful consequences. When agricultural techniques that had been developed in the temperate climate of Europe were introduced in late 18th century Australia, the result was vast areas of salinized lands (Folke and others 2002). Trying to grow lucrative oil palms on saline soils in the Indus Delta and Pakistan and the acid sulphate soils of Southeast Asia is another example of a severe mismatch between agricultural activity and ecological conditions. In the 1970s it was argued that there was a climate bias—“water blindness”—that led to efforts to transfer inappropriate agricultural technology from de- veloped to developing countries (Falkenmark 1979).

Human well-being and ecosystem services

  • e Millennium Ecosystem Assessment (MEA 2005c) showed that the well-being of hu-

man society was intimately linked to the capacity of ecosystems to provide ecosystem services and that securing multiple ecosystem services depended on healthy ecosystems.

The Aral Sea—an ecological catastrophe

The Aral Sea is probably the most prominent example of how unsustainable water management for agriculture has led to a large-scale and possibly irreversible ecological and human disaster. Reduced water ow in the rivers supplying the sea has resulted in outcomes that have impaired human liveli- hoods and health, affected the local climate, and reduced biodiversity. Since 1960 the volume of wa- ter in the Aral Sea Basin has been reduced by 75%, due mainly to reduced inows as a consequence of irrigation of close to 7 million hectares of land (UNESCO 2000; Postel 1999). This has led to the loss of 20 of 24 sh species and collapse of the shing industry; the sh catch fell from 44,000 tons annually in the 1950s to zero, with the loss of 60,000 jobs (Postel 1996). Species diversity and wildlife habitat have also declined, particularly in the wetlands associated with the sea (Postel 1999). The water diversions together with polluted runoff from agricultural land have had serious human health effects, including an increase in pulmonary diseases as winds whipped up dust and toxins from the exposed sea bed (WMO 1997).

Wind storms pick up some 100 million tons of dust containing a mix of toxic chemicals and salt from the dry sea bed and dump them on the surrounding farmland, harming and killing crops as well as people (Postel 1996). The low ows into the sea have concentrated salts and toxic chemicals, making water supplies hazardous to drink (Postel 1996). In the Amu Darya River Basin chemicals such as dichlorodiphenyl-trichloroethane (DDT), lindane, and dioxin have been carried by agricultural runoff and spread through the aquatic ecosystems and into the human food chain. Secondary salini- zation is also occurring (Williams 2002).

Attempts to rehabilitate the Northern Sea are under way through the Syr Darya and Northern Aral Sea Project (www.worldbank.org.kz); initial results are seen as positive (Pala 2006). A dam has been constructed between the two parts of the sea to allow the accumulation of water and to help reha- bilitate parts of the delta. While the project aims to reestablish and sustain shery and agricultural activities and to reduce the harmful effects on the drinking water, the extent of past changes makes restoration highly unlikely. The ecological and social changes in the Aral Sea ecosystem are consid- ered largely irreversible.


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