(1) Carbon dioxide is produced by many activities of human beings such as destruction of forests, combustion of fossil fuels, cement plants and other industries, burning and respiration by all living organisms.
(2) This CO2 forms a layer in the upper atmosphere.
(3) When solar energy reaches the earth surface, the infrared radiations from this are trapped by the layer of CO2 .
(4) Along with CO2 other gases such as methane, CFCs and nitrogen oxides also form a blanket in the atmosphere which traps the reflected infrared rays.
(5) This results in greenhouse effect and global warming. CO2 alone can increase the temperature by about 50%. During the last 50 years the average temperature of the earth has increased due to steadily increasing CO2 concentration. Thus, CO2 plays a crucial role in global warming.