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Airdate: Jan 18, 2000 Scientist: Melanie Stiassny
When it comes to the scarcity of water on Earth, it's not about how much there is, but about what kind of water, and where.
ambience: Running stream
Water everywhere but barely a drop to drink. When it comes to the scarcity of water on Earth, it's not about how much there is, but about what kind of water, and where. I'm Jim Metzner, and this is the Pulse of the Planet, presented by DuPont.
It's pretty clear that our planet has an abundance of water. So why do we so often hear that this essential resource is endangered?
"Two-thirds of the planet is covered in water but about ninety-seven point five percent of that water is ocean. It's sea. It's actually only about two point five percent of the earth's water that is actually fresh water."
Melanie Stiassny is a curator of fishes at the American Museum of Natural History. We asked her of that 2.5 percent, how much fresh water is available to us for drinking and other uses?
"An amazing sixty nine percent of the earth's fresh water is actually tied up as ice at the polar caps. About thirty percent is tied up underground, as ground water in the aquifers. About point nine percent of the earth's fresh water is, is tied up in permafrost, as a swamp moisture or, or permanent soil moisture. And that leaves us with a very, very small percentage. "
So how much fresh water does that leave for all the plants and animals of the world, including us humans? The answer is: not much.
"It's less than one hundredth of one percent of the earth's water is actually available for all of the biodiversity that lives in fresh water. But that's also the tiny percentage that we as a species actually have to use for our own needs. It's an amazingly small amount of the earth's water that's available to us."
Pulse of the Planet is presented by DuPont, bringing you the miracles of science, with additional support provided by the National Science Foundation. I'm Jim Metzner.