Water- depletion and pollution
When Neil Armstrong saw the Earth from the Moon, it appeared blue! This is because water covers more than two-thirds of the Earth's surface. But fresh water represents less than 0.5% of the total water on Earth. The rest is either in the form of seawater or locked up in icecaps or the soil, which is why one often hears of water scarcity in many areas.
Water is continuously moving around the earth and constantly changing its form. It evaporates from land and water bodies and is also produced by all forms of life on Earth. This water vapour moves through the atmosphere, condenses to form clouds and precipitates as rain and snow. In time, the water returns to where it came from, and the process begins all over again. Although water is constantly moving, its total quantity on Earth's surface is constant.
Forms of water
Water is found in three different forms - liquid, solid or gas, depending on the temperature but it constantly changes from one form to another. Changes in temperature will determine which of these forms predominates in a particular area.
Water is usually encountered in the liquid state, because this is its natural state when temperatures are between 0° C and 100° C. 'Fresh' or drinking water is found as groundwater in underground aquifers, and on the surface in ponds, lakes, and rivers. Seas and oceans account for 97% of all water on Earth; but their waters contain dissolved salts and are therefore unfit to drink. In regions of young volcanic activity, hot water emerges from the earth in hot springs (examples are Garampani in Assam and Badrinath in Uttaranchal). How does this phenomenon occur? Surface water percolates downward through the rocks below the Earth's surface to high-temperature regions surrounding a magma reservoir, either active, or recently solidified but still hot. There the water is heated, becomes less dense, and rises back to the surface through fissures and cracks.
Ice is the frozen form of water. It occurs when temperatures are below 0°C (32°F). For a given mass, ice occupies 9% more volume than water, which is why when water enters cracks in rocks and freezes it causes the rocks to crack and split. Being less dense than water, ice floats. This property of ice is vital to aquatic life in cold regions. As the temperature drops, ice forms a protective, insulating layer on the surfaces of streams, pools and other water bodies, allowing water to remain liquid in the layers beneath and life to survive. Glaciers, icebergs, and ice caps are all frozen water.
Water is found in the atmosphere in its gaseous form, water vapour. Steam is nothing but vapourized water. In certain hot water springs called geysers, jets of steam and hot water rise one hundred feet or more from the ground. Geysers are found in Iceland, the North Island of New Zealand and in USA's Yellowstone National Park.
Worldwide, the consumption of water is doubling every 20 years - more than twice the rate of increase in population.
A large amount of water is wasted in agriculture, industry, and urban areas. It has been estimated that with available technologies and better operational practices, agricultural water demand could be cut by about 50%, and that in urban areas by about 33% without affecting the quality or economics of life. But most governments do not have adequate laws or regulations to protect their water systems.
Due to the increase in population there has been a rise in the demand for food, space for housing, consumer products, etc., which has in turn resulted in increased industrialization, urbanization, and demands in agriculture thereby leading to both river and groundwater contamination.
The 'small and big' of water
The Pacific ocean is the biggest ocean covering approximately 32.6% of the Earth's surface
The Arctic ocean is the smallest ocean
Some interesting facts about water
75% of the earth's surface is covered with water
More than 97% of the earth's water is in its oceans
About 2% of the available drinking water is frozen leaving only 1% for drinking
The world's average rainfall is about 850 mm
Water regulates the Earth's temperature. It also regulates the temperature of the human body, carries nutrients and oxygen to cells, cushions joints, protects organs and tissues, and removes waste
60% - 75% of the adult human body is water - 82% of blood is water; 70% of the brain and 90% of the lungs are made up of water
Blood in animals and sap in plants is composed mainly of water
To cook 1 cup of rice you need 2 cups of water but to wash the pan in which it has been cooked you need 4-5 litres of water
A dripping tap can waste up to 6 litres of water in a day
More than half the creatures on the Earth are found under water
Life on earth probably originated in water
In the summer our bodies require about 2 litres of water daily. Here is the water content of some foods (approximate) - 95% in tomato, 91% in spinach, 91% in milk, 85% in apples and 80% in potatoes
10% of the earth's surface is covered with ice
There are more than one billion people particularly in North Africa and Western and South Asia, who lack access to a steady supply of clean water.
Access to water and sanitation, so crucial to human well-being and development, has now become a priority for the international community. To underscore the need for immediate action, the United Nations has designated 2003 as the International Year of Freshwater.
The importance given to water in ancient India is reflected in several hymns of the Vedas and epics and narratives from other valuable works such as the Arthasastra of Kautilya.
International Year of Freshwater 2003
"No single measure would do more to reduce disease and save lives in the developing world than bringing safe water and adequate sanitation to all."
- UN Secretary General Kofi Annan
2003 is the International Year of Freshwater
"Water is probably the only natural resource to touch all aspects of human civilization - from agricultural and industrial development to the cultural and religious values embedded in society."
- Koichiro Matsuura, Director General, UNESCO