Saturday, 7 March 2015
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Causes of Global warming.


Global warming is mainly caused by greenhouse gases. The main gases are carbon dioxide (CO2), methane (CH4), Chlorofluorocarbons (CFCs) and nitrogen oxide (N2O).

1. Carbon dioxide (CO2): Carbon dioxide is the main greenhouse gases. The gas contributes over 50% of the greenhouse effect. The following are the source of carbon dioxide in the atmosphere:

(a) Clearing and burning of vegetation.
Green plants, especially woody plants, absorbs carbon dioxide from the atmosphere as they grow. When the wood dies, the carbondioxide is released back into the atmosphere. Clearing of forests (deforestation) and burning vegetation result in the release of carbon dioxide to the atmosphere . Deforestation remains high in many parts. The loss of the forest also means that there are fewer trees to absorbs carbon dioxide.

(b) Burning of fossil fuel
Carbon dioxide is a byproduct in the combustion of fossil fuel such as coal, petroleum. These fossil fuel are burned in cars, power station and industries.


2. Methane.
The main source of methane is from agricultural activities. It released from wetlands, such as rice field and from animals, particular cud-chewing animal like cow. The emission of methane gas therefore increases with increase agricultural activities.
Methane also produced during the mining of coal and oil and when vegetation is burnt. Methane molecules have a life time of 10 years in the atmosphere.

3. Dinitogen oxide: Dinitogen oxide is produced from both natural and human made process. Human activities which produce dinitrogen include combustion of fossil fuels in vehicle and power stations, use of nitrogeneous fertilizer and the burning of vegetation and animal waste.

4. Chloroflourocarbons (CFCs): The sources of CFCs in the atmosphere include fridges, air condition and aerosols. CFCs are extremely effective greenhouse gases. A CFCs molecules is 10,000 times more effective in trapping heat that a carbon dioxide molecules. 

 
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