Question

Explain how does greenhouse effect cause global warming.

Answer 1

• The earth’s atmosphere allows most of the visible light from the sun to pass through and reach the earth’s surface. As earth’s surface is heated by sunlight, it radiates a part of this energy back towards the space as longer IR wavelengths. 
• Some of the heat is trapped by CH₂ , CO₂ . CFCs and water vapour present in the atmosphere. They absorb IR radiations and block a large portion of earth’s emitted radiations. 
• The radiations thus absorbed is partly remitted to the earth’s surface. Therefore the earth’s surface gets heated up by a phenomenon called greenhouse effect. 
• Thus greenhouse effect is defined as the heating up of the earth surface due to trapping of infrared radiations reflected by earth’s surface by CO₂ layer in the atmosphere. The heating up of the earth through the greenhouse effect is called global warming.