What is greenhouse effect ?
The earth which gets energy from the sunlight absorbs some of this energy and gets heated up. Then the earth cools down by giving different forms of energy called the infrared radiations.
Some of these infrared radiations are trapped by green house gases like CO2 and N2O and does not allow head radiation back to the earth’s atmosphere due to some of their chemical properties. The energy is again emitted as heat energy and causes the atmosphere to heat up, which further causes the earth’s surface to become warmer.
This is called green house effect.