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水是构成人类自然环境的基本因素.地球上拥有的水量约为十四亿五千万立方公里,其中97%是海洋(咸)水.淡水仅四千万立方公里,除去大部分为冰层或深埋在不易开发的地下的水,实际上便于人类使用的水量仅有十五万立方公里,约占地球总水量的0.01%.而全球居民生活和工农业生产每年耗费水量,已从1900年的四百立方公里,至今增加到五千立方公里,预计到2000年,用水量将达到六千至七千立方公里.更为忧虑的是,
Water is a fundamental element that constitutes the natural environment of mankind and contains about 1.45 billion cubic kilometers of water, 97% of which is marine (salty) water. Freshwater is only 40 million cubic kilometers, excluding most of the ice Or buried deep in hard-to-reach underground water, in fact, only 150,000 cubic kilometers of water are easily accessible to human beings, accounting for about 0.01% of the total earth’s water consumption. However, the annual water consumption of global residents and industrial and agricultural production has dropped from 1900 The 400-kilometer-kilometer-long year has now increased to 5,000 cubic kilometers and the water consumption is expected to reach 6-7,000 cubic kilometers by the year 2000. Even more worrisome,