The C02 in the atmosphere effectively shields the earth’s surface from the cosmic radiation of the outer space. Increase in C02 content of the atmosphere would reduce the shielding effect making the surface warmer. The buildup of C02 in the atmosphere will produce the so-called green house effect as the increased concentration of C02 will absorb the infrared radiation emitted by the earth.
Ozone (03) produced in the lower atmosphere is a serious pollutant in that it is poisonous to both plants and animals. At the same time, paradoxically ozone is absolutely essential in the stratosphere (upper atmosphere) in that it acts as a shield against ultraviolet radiation (UV).
Ultraviolet is a part of natural radiation from the sun; the wavelengths are just slightly shorter and have higher energy content than those of visible light.
However, when UV penetrates living tissues, it is preferentially absorbed by proteins or nucleic acids such as DNA, and its high energy enables it to actually break the chemical bonds of these molecules. UV is extremely destructive to biological tissues and is capable of causing mutations.
Some UV does penetrate to the surface of Earth. It is responsible for sunburn and is involved in some 200,000 to 600,000 cases of skin cancer per year in the U.S. However, we are spared the worst effects of UV because most of it is absorbed and, hence, screened out by the ozone in the stratosphere.
Without this ozone “shield”, the biological damage to both plants and animals would be disastrous. Indeed, it is doubtful whether life could even exist on land without the protection of the ozone layer.
The stratosphere 03 layer varies reasonably in thickness between 2.4-2.6 mm at the equator and 3.1-4.3 mm at 70°-m latitude. 03 layers exist only because our atmosphere contains or without 02, it could not have produced 03 and formed the protective 03 layer.
The ozone layer is generally located between 15 km and 40 km above the earth, but its highest density is at 25 km. Between 200 and 290 mm range, UV is destructive to life but is efficiently absorbed by 02 and 03 in the atmosphere.
Certain pollutants diffusing gradually into the stratosphere from the lower atmosphere have damaging effects on the ozone layer. In particular, chlorine atoms catalyze the breakdown of ozone.
A single chlorine atom can break down millions of molecules of ozone, upsetting the natural ozone balance. A major potential source of chlorine, reaching the stratosphere is the chlorofluorocarbons such as Freon (CFC13) used as a propellant in aerosol cans and as refrigerants.
Some 300 million tonnes of chlorine are released into the atmosphere every year by the evaporation of sea water which contains salt (sodium chloride). Large amounts of this chlorine reach the stratosphere, through the pumping action of thunderstorms, hurricanes, typhoons and other cyclonic activity which also break up the sodium chloride molecules. There are 4.2 million tons of chlorine gases produced by the burning of biomass, largely due to slash and burn agricultures methods.
Nitrogen oxide produced by high altitude aircraft, such as the supersonic transports, nitrogen fertilizers and automobile exhaust, can break down ozone in a manner similar to chlorine.
Because of this fact and due to heavy depletion of nonrenewable energy sources like oil and coal and due to increasing demand for energy, there is obvious need for the search of alternative renewable sources of energy such as sun, wind, biomass, etc.
The exhaustible energy resource is one which is a nonaugmen able stock; when used up, it is gone. The renewable energy resource is an augmentable resource flow; one can tap into the resource flow at any time without reducing the amount available in the future.
Hydro, solar and wind energy are augmentable in the broadest sense; the amount of flowing water is given, as is wind speed and the level of insolation, but know ledge of total annual flows, from these sources, offers little guidance to future energy supply unless the resource concept is given an economic dimension. Once this part is over augmentation is possible through improved technology or higher prices.
The energy potential of a nation has direct correlation with economic growth and prosperity. The stage of development is well reflected by the per capita energy consumption of a country.
The deepening energy crisis, with which the world community is confronted, has led to the formulation of an energy policy framework within which the rate of growth and pattern of energy consumption could be regulated. In this context, a transition may be considered necessary.
The required transition is to shift from fossil and non-renewable sources such as petroleum, coal and uranium to renewable energy sources like hydroelectric, solar, Wind, biogas, etc.
The main energy sources of a country have been usually decided into commercial and non-commercial sources. Commercial sources consist of coal, oil, natural gas, hydroelectric power and nuclear fuel. Under non-commercial category, the main sources are livestock, forest, vegetable waste which mainly consists of crops residue and cow dung.
Besides, there are some important non-conventional sources as well. These are solar, biogas, wind mill and tidal. India has sufficient potential of all these energy sources.