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Of the 2.5% of water that is not salty, about 70% is frozen, either at the poles, inglaciers or in permafrost. So all living things, except those in the sea, have about 0.75% of the total to survive on. Most of this available water is underground, in aquifers or similar formations. The rest is falling as rain, sitting in lakes and reservoirsor flowing in rivers where it is, with luck, replaced by rainfall and melting snow andice. There is also, take note, water vapor in the atmosphere.
在这2.5%的不含盐的水中，约有70%处于冰冻状态，储存在南北两极、冰川或永久冻土里。因此，除海洋生物之外，所有其他生物只能依赖占总量约0.75%的水生存。这些可用的水大部分在地下，存在于地下蓄水层或类似的结构中。其他部分以雨的形式落下，储存于湖泊、水库之中或在江河中流淌，这些江河，如果幸运的话，会得到雨水及融化了的冰雪的补充。值得注意的是，还有一部分水蒸发在大气中。
The value of water as a commodity of course varies according to locality, purpose and circumstance. Take locality first. Water is not evenly distributed—just nine countries account for 60% of all available fresh supplies—and among them only Brazil, Canada, Colombia, Congo, Indonesia and Russia have an abundance. America is relatively well off, but China and India, with over a third of the world's population between them, have less than 10% of its water.
水作为一种商品，其价值自然因地域、使用目的与具体情况的差异而有所不同。首先看看地域的影响。水并非均衡分布的——仅9个国家就拥有全部可用淡水的60%——其中仅巴西、加拿大、哥伦比亚、刚果、印度尼西亚和俄罗斯水资源十分丰富。美国的水资源也相对较丰富，而中国和印度，尽管两国的人口加起来超过世界人口的三分之一，但是所拥有的水资源还不到10%。
Even within countries the variations may be huge. The average annual rainfall in India'snortheast is 110 times that in its western desert. And many places have plenty of water, or even far too much. Flooding is routine, and may become more frequent and damaging with climate change.
即便在各个国家境内，水资源分布的差别也可能是巨大的。在印度东北部，年平均降雨虽是西部沙漠地区的110倍。许多地方有充足的水，甚至水太多了。那样的地方水灾成了家常便饭，而且由于气候的变化，水灾会越来越频繁，破坏性也越来越强。
