How is excessive content of CO₂ responsible for global warming? 

Due to the excess combustion, the concentration of CO₂ increases beyond a certain level. Some of the CO₂ is utilised by plants during photosynthesis and O₂ is released into the atmosphere while the remaining concentration of CO₂ will always remain unutilized. This excess CO₂ absorbs heat radiated by the earth. Some of it is dissipated into the atmosphere while the remaining part is radiated back toward the earth’s surface and other bodies present on the earth. As a result, the temperature of the earth and other bodies on the earth increases. This is called greenhouse effect and CO₂ is called green house gas. Due to green -house effect, global warming occurs which has serious consequences.