Green house effect:

• When the sunlight reaches earth's surface, some of it is absorbed and warms the earth. Most of it is radiated back to the atmosphere at a longer wavelength than the sunlight.
• Some of these longer wavelengths are absorbed by the greenhouse gases in the atmosphere and reflect them back to the earth before they are lost to space.
• The absorption of this longwave radiant energy warms the atmosphere. The reflecting back of heat energy by the atmosphere is called 'Greenhouse effect'.
• The increase in man-made emissions causes an increase in the atmosphere of greenhouse gas concentrations like water vapour, carbon-dioxide, methane, ozone contributing to the greenhouse effect.
• The largest contributing sources is burning of fossil fuel like oil, gas, petrol, kerosene etc leading to the emission of carbon-dioxide.
• Green house effect can happen even without any plants being grown in green house.
• This phenomenon was extrapolated to earth's atmosphere. The radiation received by earth but not able to be reflected can become 'Green house' effect.
• That is short waves of infrared and rear infrared rays are trapped in the layer immediately above the earth's surface - just like a green house.