Tampa, Florida area every week (Figure20.4). Tampa’s population is growing quickly. The
Tampa area may have over 3 million people by 2010. One of Tampa’s rivers, the Hillsbor-
ough River, is pumped for drinking water to support all the people. Too much water is being
taken from the river. The river is becoming salty, as water from the near-by Gulf of Mexico
starts to take the place of thefreshwaterbeing pumped out. This hurts wildlife and may
eventually make the river water unsuitable for human use. Many other examples like this
are taking place worldwide.
Figure 20.4: Downtown Tampa, Florida is growing at an enormous rate. The growing human
population puts a strain on natural resources, like rivers and other bodies of water. ( 1 )
Resource Availability
Youcanseefromthetableabovethatmanyoftheresourceswedependonarenon-renewable.
We will not be able to keep taking them from the Earth forever. Also, non-renewable
resources vary in their availability. Some are very abundant and others are rare. Precious
gems, like diamonds and rubies, are valuable in part because they are so rare. They are
found only in small areas of the world. Other materials, like gravel or sand are easily located
and used. Whether a resource is rare or abundant, what really determines its value is how
easy it is to get to it and take it from the Earth. If a resource is buried too deep in the Earth
or is somehow too difficult to get, then we don’t use it as much. For example, the oceans
are filled with an abundant supply of water, but it is too salty for drinking and it is difficult
to get the salt out, so we do not use it for most of our water needs.
Resource availability also varies greatly among different countries of the world. For example,
11 countries (Algeria, Indonesia, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia,