Burning of fossil fuels, deforestation and agricultural activities release a lot of carbon dioxide in air. The increased amount of carbon dioxide gas in the air traps the heat radiated from the earth. This trapping of heat by CO2 layer in air is called greenhouse effect. This leads to an overall increase in the temperature of the earth. This is called global warming. Global warming results in melting of polar ice which causes a rise in the sea level, leading to floods in the low lying coastal areas having fertile land.
