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我们居住的地球表面,70%被海洋覆盖着,海水占地球水体总储量的97%,淡水只占2%左右。在淡水储量中,87%又储存在两极冰川与永久冻土中,只有0.4%分布在河流湖泊、土壤之中。全世界目前淡水用量4.13万亿立方米,农业和工业用水分别占世界用水总量的70%和25%。因人口增长,本世纪末全球淡水使用量将增至7万亿立方米,人均水资源拥有量将减少24%,年人均可供水量将由目前的3000立方米降至2280立方米。按一个国家人均每年供水不足1000立方米即为缺水国家的标准,目前世界上有80个国
70% of the Earth’s surface we live in is covered by oceans, which account for 97% of the Earth’s total water reserves and about 2% of fresh water. Of the freshwater reserves, 87% are stored in polar glaciers and permafrost, with only 0.4% of them distributed in rivers, lakes and soils. The world’s current freshwater consumption is 4.13 trillion cubic meters and that of agriculture and industrial water accounts for 70% and 25% of the world’s total water consumption respectively. Due to population growth, the global fresh water use will increase to 7 trillion cubic meters by the end of this century, the per capita water resource ownership will decrease by 24% and the annual per capita water supply will be reduced from the current 3,000 cubic meters to 2,280 cubic meters. According to a country’s per capita annual supply of less than 1,000 cubic meters is the standard of water-scarce countries, the world has 80 countries