What are greenhouse gasses? how does carbon dioxide enter the atmosphere? click through all four pages of the article

1. Greenhouse gases are compounds that are able to trap heat in the atmosphere, keeping the Earth's surface warmer than it would be if they were not present. The gases are the fundamental cause of the greenhouse effect. Increase in the amount of greenhouse gases in the atmosphere enhances the greenhouse effect which is creating global warming and consequently the climate change. These gases are mainly carbon dioxide; metahne, nitrous oxide, and flourinated gases. 
 
2. Carbon dioxide enters the atmosphere from animals and plants through the process of respiration and the burning of fossil fuels from industries. .
Animals and plants get rid of carbon dioxide gas through respiration. Carbon may also move from fossil fuels to the atmosphere when fuels are burned. Burning of fuels to power factories, power plants, cars and trucks makes carbon to enter the atmosphere as carbon dioxide.