Tamilnow Articles -> Global Warming, Green House Effect & Green House Gases
Global warming is one of the current environmental issues .The world development has been human oriented and development have touched the greatest heights of science and technology, but still at what cost? The air we breathe, water we drink and the food we eat have all been badly polluted. The main cause for global warming is the atmosphere getting polluted due to many reasons. Global warming is defined as the increase in the earth’s atmospheric temperature.
Industrial growth reduces the self cleansing power of the earth. Industrial effluents affect the ecosystem and disturb the food chain. Climatic changes cause global warming. Air pollution increases the level of carbon dioxide in the air. The effect of this is that the atmosphere retains more of the heat of sunlight. This naturally causes increase in the temperature of the atmosphere. This is called global warming.
Scientists have detected that an increase in the temperature of the atmosphere in the past 100 years and they say it will keep increasing in the coming years. They have warned that because of this heating, the ice at the poles will start melting, resulting in floods in the low lying lands on sea shores.
More fossil fuels increase the carbon dioxide content in the atmosphere. It causes “Green House Effect” and “Global Warming”. They threaten the climatic conditions.
Green house effect:
The earth is heated by sunlight and some of the absorbed heat by earth is radiated back into earth. However some of the gases in the lower temperature acting like green house allow the solar radiations but do not allow the earth to re-radiate the heat into space, that is these gases in the atmosphere are transparent to sunlight coming in but they absorb radiations with which the earth sends back as heat.
A part of the heat trapped in these atmospheric gases is re-emitted to the earth’s surface which result in heating the earth’’s surface by a phenomenon called "Green house effect".
Major Green house gases are:
CO2, water vapour
CH4, man made chlorofluro carbon (CFC)
N2O Nitrous oxide
Sources of these gases are:
CO2-Combustion deforestation, volcanic eruption , decaying plants etc.
CH4- Decomposition of organic matter ,coal mines.
CFC- Industrial applications.
In fact, Green house gases are responsible for keeping our planet warm and thus sustaining life on earth. If they are totally absent in atmosphere, then the average temperature would have been sub-zero level. If it is large, they trap too much of heat which affect the life on the earth.
Oceans and biomass are the major sinks for the atmospheric CO2. Ocean converts CO2 into soluble bicarbonates. Photosynthesis in green plants which increases by increasing CO2 in vast reservoir of forest. Hence forests maintain a balance in the atmosphere CO2 level. Now CO2 content has increased 25% compared with last year, this is the reason for increase in global temperature.