What is the hydrological cycle? • It refers to the continuous movement of water from the Earth’s surface to the atmosphere and back again.
SKETCHING AND ANNOTATION EXERCISE http://www.youtube.com/watch?v=0_c0ZzZfC8c
Water “scarcity” SUPPLY • An economic principle • Where supply > demand. :. We have a water shortage/constraint. DEMAND
How can there be water scarcity when 75% of the earth’s surface is made of water?
Only 1 percent of total amount of water on earth is fresh water http://snr-1349.unl.edu/images/waterdist.gif