Water Supply of the World

The Antarctic Icecap is the largest supply of fresh water, representing nearly 2% of the world's total of fresh and salt water. As can be seen from the table below, the amount of water in our atmosphere is over 10 times as much as the water in all the rivers taken together. The fresh water actually available for human use in lakes and rivers and the accessible ground water amount to only about one-third of 1% of the world's total water supply.

  Surface area (sq mi) Volume (cu mi) Percentage of total1
Salt water
 The oceans 139,500,000 317,000,000 97.2%
 Inland seas and saline lakes 270,000 25,000 0.008 
Fresh water
 Freshwater lakes 330,000 30,000 0.009 
 All rivers (average level) 300 0.0001 
 Antarctic Icecap 6,000,000 6,300,000 1.9 
 Arctic Icecap and glaciers 900,000 680,000 0.21 
 Water in the atmosphere 197,000,000 3,100 0.001 
 Ground water within half
  a mile from surface
1,000,000 0.31 
 Deep-lying ground water 1,000,000 0.31 
 Total (rounded) 326,000,000 100.00 
1. All figures are estimated.
Source: Department of the Interior, Geological Survey.

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