Question

What do you mean by global warning?

Answer 1

Green house gases absorbs the radiation (heat) , which is coming from earth's surface after reflection , and radiate some heat to the outer space and some , into the earth's atmosphere . Due to that process , earth's atmosphere remains warm , even in night when sun radiation is not available i.e. green house gases maintain the temperature of earth's atmosphere . This is natural green house effect , but now a days due to various causes of air pollution the amount of green house gases ($C{O}_2,C{H}_4$ etc.) is increased , it means that now more heat is stopped by gases into earth's atmosphere , therefore average temperature of earth's atmosphere is increasing , this is called global warming .