ABSTRACT
As Earth’s population reached the 7 billion mark at the end of October 2011, the demands that population growth place upon the planet’s nite resources are matters of very serious concern, much of them involving energy, especially petroleum resources. But, arguably, a more urgent concern with respect to Earth’s natural capital is water and it has become fashionable to say that water is the new petroleum. In a sense, the problems posed by shortages of water and deteriorating water quality in many areas of the world are much more challenging than those of energy. There are numerous options for supplying energy, including renewable resources such as wind energy and solar energy. But, overall, there is a nite amount of water on Earth, especially if water in the oceans is regarded as being largely off-limits as a source of usable H2O. Although water, like petroleum, can be moved some distances, to a large extent, “you have got to use it where you nd it,” and the uneven distribution of water around the planet makes its utilization in an economical way rather difcult in many areas.
