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最近,联合国环境规划署作出了坦率而又令人不安的预测:水问题将会同70年代的能源问题一样,成为下世纪初世界大部分地区面临的最严峻的自然资源问题。联合国的分析资料指出:地球的淡水比例仅占2.6％左右,其中99％以上蕴藏在南北两极的冰雪中或在地下,其余不到1％的淡水又有将近一半被土壤和空气吸收,余下的部分蕴藏在地球表面分布极不均等的江河湖泊之中。据统计:过去50年,全世界淡水使用量增加将近4倍,每年高达4 130立方千米,农业用水占全部用水的60％,因为过去20年中,灌溉面积增加了1/3以上。亚洲国家的
Recently, the United Nations Environment Program made a frank and disturbing prediction that the water issue will, like the energy issue in the 1970s, become the most serious natural resource problem facing most parts of the world at the beginning of the next century. According to the United Nations analysis data, only about 2.6% of the earth’s fresh water is accounted for, of which over 99% are contained in the ice and snow in the north and south poles or in the ground, and nearly half of the remaining fresh water, less than 1%, is absorbed by soil and air. Part of the earth’s surface contains extremely unequal distribution of rivers and lakes. Statistics show that fresh water use in the world has nearly quadrupled in use in the past 50 years, reaching 4 130 cubic kilometers per year. Agricultural water accounts for 60% of total water use, as irrigated area has increased by more than a third in the past 20 years. Asian countries