What is the one natural substance that is MOST vital to life on Earth? Water. Without water, life is impossible for most creatures and plants. Clean water is essential to life, and as the Earth’s population grows, water is becoming more and more a limiting factor to human life. Concentrating populations in cities places additional demands on our ability to supply growing urban areas with adequate fresh, clean water. Water is becoming our most valuable resource, especially in urban areas.
Today, half of the planet’s population lives in urban areas and the world’s cities and towns are growing at an unprecedented rate. According to the United Nations (World Urbanization Prospects: The 2009 Revision), the urban areas of the world are expected to absorb all the population growth expected over the next four decades while at the same time drawing in some of the rural population. Globally, the level of urbanization is expected to rise from 50 per cent in 2009 to 69 per cent in 2050.