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 Earth as rivers, oceans, ice, plants, and dogs, 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 Earth's water is saline and in the oceans. And of the small amount that isactually freshwater, only a relatively small portion is available to sustain human, plant, and animal life.
The globe image is meant to show how much actual water exists, as compared to the total size of the Earth. The spheres look small because it is compared to the size of the whole globe. What it show is 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).|