Water: A Finite Resource

Water is an essential requirement for any form of life. The earth is blessed with huge volumes of water at the surface, which is one of the main reasons why it is habitable. Seventy percent of the earth’s surface is covered by sea, and the weather continually recycles fresh water from rain through rivers and soil. One of the remarkable features of our planet is that throughout the four-billion-year history of life, its surface temperature has stayed between the limits of 0° C (32°F), when everything would freeze, and 0-100°C (212°F), when all the water would boil off into space.

This…