Water covers 70.9% of the Earth's surface, and is vital for all known forms of life. On Earth, 96.5% of the planet's water is found in oceans, 1.7% in groundwater, 1.7% in glaciers and the ice caps of Antarctica and Greenland, a small fraction in other large water bodies, and 0.001% in the air as vapor,cloud (formed of solid and liquid water particles suspended in air), and precipitation. Only 2.5% of the Earth's water is freshwater, and 98.8% of that water is in ice and groundwater. Less than 0.3% of all freshwater is in rivers, lakes, and the atmosphere, and an even smaller amount of the Earth's freshwater (0.003%) is contained within biological bodies and manufactured products.
Water security is the capacity of a population to ensure that they continue to have access to potable water
Lately,Water security is rapidly declining in many parts of the world after all sorts of challenges coming on the way such as population growth,drought,climate change,urban drift,salinity,upstream pollution,over-utilisation from ground water and etc
Let us focus on the causes of this event
The concepts of water stress and water scarcity are relatively new. Fifty years ago, when there were fewer than half the current number of people on the planet, the common perception was that water was an infinite resource. People were not as wealthy then as they are today, consumed fewer calories and ate less meat, so less water was needed to produce their food. They required a third of the volume of water we presently take from rivers. Today, the competition for water resources is much more intense. This is because there are now nearly seven billion people on the planet, their consumption of water-thirsty meat and vegetables is rising, and there is increasing competition for water from industry, urbanisation and biofuel crops.
The total amount of available freshwater supply is also decreasing because of climate change, which has caused receding glaciers, reduced stream and river flow, and shrinking lakes. Many aquifers have been over-pumped and are not recharging quickly. Although the total fresh water supply is not used up, much has become polluted, salted, unsuitable or otherwise unavailable for drinking, industry and agriculture. To avoid a global water crisis, farmers will have to strive to increase productivity to meet growing demands for food, while industry and cities find ways to use water more efficientl