The process of trapping of radiation by the earth’s atmosphere is called green house effect. By this process the warming of earth takes places. Without this process life would not have been possible on earth. But now it threatens life.
Carbon dioxide, methane, nitrous oxide, water vapour and CFCs are called green house gases because they all contribute towards this effect.
Carbon dioxide is one of the components of air. As the amount of carbon dioxide increase in the atmosphere due to which more green house effect takes place. As a result the average temperature of the earth’s atmosphere is gradually increasing. This is called global warming.