Diary of forthconing events |
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| Authors: | GEORGE H LEAVESLEY GREGG C LUSBY ROBERT W LICHTY |
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| Institution: | US Geological Survey , Box 25046, MS 412, Denver Federal Center, Denver , Colorado , 80225-0046 , USA |
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| Abstract: | Abstract New global models provide the opportunity to generate quantitative information about the world water situation. Here the WaterGAP 2 model is used to compute globally comprehensive estimates about water availability, water withdrawals, and other indicators on the river-basin scale. In applying the model to the current global water situation, it was found that about 24% of world river basin area has a withdrawal to availability ratio greater than 0.4, which some experts consider to be a rough indication of “severe water stress”; the impacts of this stress are expected to be stronger in developing countries than in industrialized ones. Under a “business-as-usual” scenario of continuing demographic, economic and technological trends up to 2025, water withdrawals are expected to stabilize or decrease in 41% of world river basin areas because of the saturation of water needs and improvement in water-use efficiency. Withdrawals grow elsewhere because population and economic growth will lead to rising demand for water, and this outweighs the assumed improvements in water-use efficiency. An uncertainty analysis showed that the uncertainty of these estimates is likely to have a strong geographic variability. |
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| Keywords: | global water resources hydrological model integrated assessment scenario analysis water scarcity water stress water availability water use water withdrawals |
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