“We shall not finally defeat AIDS, tuberculosis, malaria or any of the other infectious diseases that plague the developing world until we have also won the battle for safe drinking-water, sanitation and basic health care.” (Kofi Annan, United Nations Secretary-General (2005.) The International Decade for Action 2003–2015)

Freshwater is a natural resource that is vital for human survival and health. The Earth is a very wet planet, but only 2.53% of its water is fresh; the rest is seawater (UNESCO, 2003). There is currently much concern about the capacity of the Earth's freshwater resources to sustain human life and health in the near future. One estimate suggests that, if current trends continue, by 2050, when the global human population will reach almost nine billion people, seven billion people in 60 countries will be short of water unless action is taken (UNESCO, 2003). Half the human population will be short of water by 2025. (Note: 1 billion = 1000 million.)

Planet Earth contains an enormous amount of water, but only a tiny fraction of it is available as freshwater to plants and animals, including humans, that live on land. As can be seen here, only about 0.01% of the world's total freshwater is readily available to terrestrial life

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