The World's Water
http://water.usgs.gov/edu/earthwherewater.html
"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.
Distribution of Earth's Water
• In the first bar, notice how only 2.5% of all Earth's water is
freshwater, which is what life needs to survive.
• The middle bar shows the breakdown on that 2.5% which is
freshwater. Almost all of it is locked up in ice and in the
ground. Only a bit more than 1.2% of all freshwater (which
was only 2.5% of all water) is surface water, which serves
most of life's needs.
• The right side bar shows the breakdown of only the surface
freshwater, which was only about 1.2% of all freshwater.
Most of surface freshwater is locked up in ice, and another
20.9% is in lakes. Notice the 0.49% of surface freshwater
that is in rivers. Sounds like a tiny amount, but rivers are
where humans get a large portion of their water from. In
fact, look at the globe to the right. There is a tiny 3rd bubble
hovering over Georgia, USA. That is the size of a ball of
water with all the freshwater in lakes and rivers, yet the
water in that bubble has the huge responsibility of serving
most of humans' and animals' water needs.
View a larger version of this image and learn more.
All of the World's Water
All Earth's water, liquid fresh water, and water in lakes and
rivers
Spheres showing:
(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.
One estimate of global water distribution
(Percents are rounded, so will not add to 100)
Water source
Water volume, in cubic miles
Oceans, Seas, & Bays
Ice caps, Glaciers, & Permanent Snow
Ground water
Fresh
Saline
Soil Moisture
Ground Ice & Permafrost
Lakes
Fresh
Saline
Atmosphere
Swamp Water
Rivers
Biological Water
321,000,000
5,773,000
5,614,000
2,526,000
3,088,000
3,959
71,970
42,320
21,830
20,490
3,095
2,752
509
269
Source: Igor Shiklomanov's chapter "World fresh water resources" in Peter H. Gleic
(Oxford University P