Limits of Water on Earth
Date: Summer 2009
Is the water on Earth limited, or unlimited? Is there a
day when the Earth will be completely dry?
The total water supply on planet earth is fixed.
There is no additional water being added to planet earth.
So the amount of water available is 'limited'.
But the water is not being depleted either because it recycles.
Sea water evaporates to rain that falls to the earth,
Gathers in rivers and flows down to the seas again (like the Mekong River)
In an ever unending cycle.
Even human water consumption is re-cycled.
Human waste products are removed from water in water treatment plants
and then it is returned to the environment.
In areas that do not have water treatment plants,
Human waste can be placed in natural environments for cleaning and
There is a town in Southern California that uses a swamp of water hyacinth
To completely, naturally recycle human waste.
70.8% of the surface is water, 29.2 % is land.
Unless a planetary event happens, such as an asteroid hit or
A resurgence of volcanism, the earth will not run dry.
Why don't you go to school and become a water scientist?
There will be a great demand for them in the future.
You can have fun doing what you like and you will have a job to raise a
There is not an unlimited supply of water on the Earth. Most of the water, in
fact, cannot be used for drinking. The majority of water on planet Earth is
in the oceans and in the polar ice caps. That leaves about1 to 2 percent
"fresh" water for farming, cooking, drinking, etc. And this water is not
uniformly distributed around the globe. As the supply of "fresh" water
dwindles armed conflicts are going to occur.
The amount of water on Earth is limited.
We could create more, but there are natural
mechanisms that tend to keep the amount of
water on Earth at a fixed amount.
Water molecules, or the elements that they
are composed of (hydrogen and oxygen) are
very slowly escaping from Earth's atmosphere
to space, but so slowly that you do not have
to be worried about it.
Theoretically, Earth will lose all of its
atmosphere someday, perhaps billions of years
from now, including all of the water
in the atmosphere. At that point, without an
atmosphere, Earth's surface will be much colder.
However, some water will probably remain frozen
in the soil and some will remain beneath the
Earth's surface, just as apparently happened on Mars.
David R. Cook
Climate Research Section
Environmental Science Division
Argonne National Laboratory
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