What is Global warming??

Our earth daily absorbs large quantity of solar energy from the sun. Most of this energy is radiated back to atmosphere by the earth, and this process maintains the balance of heat an energy on the earth. There are many gases present in the atmosphere, but only carbon dioxide and water vapor absorb this infrared radiation of the earth strongly and effectively block the radiation of energy back to the atmosphere. However a considerable part of it is re-emitted to the earth's surface and consequently the earth's surface gets heated up. This increase in temperature of the earth is called the Green-house effect.

The temperature effects of carbon dioxide and water vapor combine together to have a long range impact on the global climate. As the surface temperature increase, the evaporation of surface water increase, thereby raising the temperature further. It is estimated that this combined effect of rise of temperature will bring about 30 degree Celsius in surface temperature, if the carbon dioxide concentration is doubled in the atmosphere. The most alarming fact is that a slight increase in surface temperature say around 1 degree Celsius can adversely affect the world food production. As a result the wheat growing zones in the northern latitude will be shifted from USSR and Canada to the northern poles, that means from the fertile solids to the poor soils. The biological productivity will also decrease due to warming of the surface layer, which in turn reduces the transport of nutrients from deeper layers to the surface by vertical circulation.

Carbon dioxide gas, although a relatively insignificant non-pollutant gas in the atmosphere, is of serious environmental concerns. It has the potential to be compared with the nuclear wars in terms of massive irreversible damage to the environment. Increase of carbon-dioxide gas in the atmosphere is constantly occurring. Primarily through natural causes but mostly by man himself. Volcanic eruptions and forest-fire are some of the natural causes which cannot be checked. But the current global trend in deforestation, along with increase in carbon dioxide content. Forest are the areas where the green leaves efficiently utilize carbon-dioxide to make their on food. Deforestation reduces this utilization of carbon-dioxide. Consumption of fossil fuels and house-hold fuels like coal, firewood also gives off considerable amount of carbon-dioxide.

Rise in global temperatures causes many climatic changes also, but the most drastic change will be the increase in sea-level. Already, the rise in global temperatures have resulted in cracks in the Antartic ice shelf. Melting of even fraction of the volume of polar ice can result in flooding of many low lying areas around the earth. Other climate changes include floods, droughts, storms and exceptionally warm summers. Europe and American have already witnessed these changes considerably. The summer of 1998 predicted to be the warmest in the century.

Prevention is always better than cure. Human contribution and efforts can certainly prevent and control this global warming. It can be best carried out by checking atmospheric pollution. Deforestation should be stopped. Wood should be used as little as possible, because wood maintains vast reservoirs of fixed but readily oxidizable carbon. Bricks houses should be encouraged as they retain less heat. Thus they are well suited to Indian climate.

Unnecessary combustion of fuel should be checked. In houses, combustion of fuels like wood, coal, kerosene should be controlled. Instead LPG stove should be used which results in greater efficiency in fuel, utilization and less atmospheric pollution. Encouraging bio-gas plants in village communities has Multifood effect. It decreases the use of firewood, is less atmospheric pollutant and is a by-production of manure. Development of more efficient vehicles would also result in less consumption of fuel and therefore less atmospheric pollution.

Renewable sources of energy should be used as it is non-polluting and very efficient. These renewable sources of energy are solar energy and wind energy. Hydro-electricity is also of considerable use. Lastly, treatment appliances should be applied on the sources of green house gases which are carbon dioxide and methane, so that they may not violate the atmospheric balance.