地球表面的2/3虽然被水覆盖,但其中97.5%是咸水,在余下的2.5%淡水中,其中70%以上被冻结在南极和北极的冰盖中,加上难以利用的高山冰川和永冻积雪,有87%的淡水资源难以利用。人类真正能够利用的淡水资源是江河湖泊和地下水中的一部分,约占地球总水量的0.26%。进入21世纪,水的供求矛盾变得更为突出。 While 2/3 of the Earth’s surface is covered by water, 97.5 per cent of it is salt water, of which over 70 per cent of the remaining 2.5 per cent of fresh water is frozen in the Antarctic and Arctic ice caps, together with hard-to-use alpine glaciers and Frozen snow forever, 87% of freshwater resources difficult to use. Freshwater resources that humans can really use are part of rivers, lakes and groundwater, accounting for about 0.26% of the Earth’s total water. Into the 21st century, the contradiction between supply and demand of water has become more prominent.