The USGS Water Science School
"Water, Water, Everywhere...."
You've heard the phrase, and for water, it really is true. Earth's water is (almost) everywhere: above the Earth in the air and clouds, on the surface of the Earth in rivers, oceans, ice, plants, in living organisms, and inside the Earth in the top few miles of the ground.
Below are two representations of where Earth's water resides. The left-side bar chart shows how almost all of Earth's water is saline and is found in the oceans. Of the small amount that is actually freshwater, only a relatively small portion is available to sustain human, plant, and animal life.
The globe image represents how much actual water exists, compared to the total size of the Earth. Notice the blue spheres (representing water). They look small because they are being compared to the size of the whole globe. The image shows that Earth's water resides in a very thin slice all around the Earth's surface.
(1) All water (sphere over western U.S., 860 miles in diameter)
(2) Fresh liquid water in the ground, lakes, swamps, and rivers (sphere over Kentucky, 169.5 miles in diameter), and
(3) Fresh-water lakes and rivers (sphere over Georgia, 34.9 miles in diameter).
Credit: Howard Perlman, USGS; globe illustration by Jack Cook, Woods Hole Oceanographic Institution (©); Adam Nieman.
|Water source||Water volume, in cubic miles||Water volume, in cubic kilometers||Percent of|
|Oceans, Seas, & Bays||321,000,000||1,338,000,000||--||96.5|
|Ice caps, Glaciers, & Permanent Snow||5,773,000||24,064,000||68.7||1.74|
|Ground Ice & Permafrost||71,970||300,000||0.86||0.022|
|Source: Igor Shiklomanov's chapter "World fresh water resources" in Peter H. Gleick (editor), 1993, Water in Crisis: A Guide to the World's Fresh Water Resources (Oxford University Press, New York).|