The Demand for Water
1- History of Water
2- The Water Cycle & Sherwood Sandstone
3- The Demand for Water
4- Water Supply in Developing Countries
History of Water
Water molecules are made up of two hydrogen atoms combined with one oxygen atom.
Water first came to planet Earth about 4 billion years ago, by giant comets, which are capable of carrying billions of tonnes of water.
Deep inside our planet, high temperature volcanic springs released hydrogen and oxygen atoms into the atmosphere, which reacted violently together.
The resultant stormy vapour built up over the next 3 billion years to create a protective envelope, which trapped the sun’s heat.
The world, which was back then in deep freeze, slowly warmed, and the frozen water molecules started to defrost.
Steam condensed, rain fell, forming rivers and oceans. Water evaporated, and started the first ever water cycle. This first rainfall has since circled the world through the cycle over 8 million times.
Every day Earth loses water to outer space, but 20 miles down towards the Earth’s core, a giant reservoir of water (ten times the size of all the Earth’s oceans), slowly releases more water through volcanoes and “black smokers” - super heated underwater volcanoes releasing high mineral content springs.
The bacteria living off these springs are thought to be almost identical to those that lived 3.8 billion years ago: the ancestors of us, and all living things. All living things still need water to survive.
75% of a human brain is water and 75% of a living tree is water. Water makes up about 70% of a human body, and is used to regulate body temperature, carry nutrients and oxygen to cells, cushion joints, protect tissues and organs, and remove waste. A person can live a month without food, but only about a week without water.
Water is the most common substance on the planet. Water vapour in clouds consists of water molecules constantly bumping and reacting, releasing and absorbing energy; which causes storms, thunder and lightning. The passage of water over land, through streams and rivers, or by glaciers and ice sheets has split continents and changed land mass. Water regulates the planet's temperature.
The water that exists today is the same that existed 4 billion years ago. Part of the water in a human body would have once existed as part of a Neolithic man, sabre-toothed tiger or Triassic dinosaur.
About 70% of the Earth’s surface is water. Only 2.5% of the planet’s total water is not salty, and two-thirds of that is locked in ice and glaciers. Of the remaining amount, 20% is in areas too remote for human access, and of the remaining 80%, three quarters comes at the wrong time and place (monsoons and floods), and is not captured for use by people. The remainder, which can be used by the human population, is less than 0.08 of 1% of the planet's total water.