Without water there can be no life. Although the earth is called the "blue planet" because three-fourths of its surface is covered with water, only three percent of it is fresh water, and most of that is bound in the polar ice. Less than one percent of the world's water supply can be used by humans in its natural state. Yet the population is growing, and so is the water consumption per capita. The world’s most important resource is becoming increasingly scarce.

Already, one billion people lack access to clean drinking water. Two billion have no sanitary facilities. More than 50 of the Earth’s countries do not have enough water; many conflicts are sparked by questions of how to distribute the scarce supplies. On average, 4,500 children die every day from infections caused by unclean water. Pollution, climate change and natural disasters are turning arid regions into deserts. Forests, which bind water, are being cleared. The ecological water balance is steadily eroding—clean water is becoming more valuable than oil.