The water that makes all life possible today is the same water that kept dinosaurs alive, before man roamed the Earth millions of years ago. The amount of water has not changed. It has continuously been recycled from the ocean to the air and back to the Earth, changing from a solid to liquid to gas again and again.
With the limited supply of available freshwater, protecting this elixir of life is essential. However, a burgeoning human population, mostly in the last 100 years, has been altering the water cycle at an extremely rapid rate.