Many chemical compounds found in the earth’s atmosphere act as greenhouse gases. They trap the heat from the sun keeping the earth warm enough to live on. Some gases are made by nature and humans (water vapor, carbon dioxide, methane, and nitrous oxide), while others are only made by humans (fluorinated gases). When humans release these gases into the air it is called emission. Putting too much of these gases into the air causes global warming. Greenhouse gases include water vapor, carbon dioxide, nitrous oxide, methane, hydrofluorocarbons, perfluorocarbons and sulfur hexaflouride. Carbon dioxide emissions from the burning of fossil fuels is slinked to climate change.

Additional Resourses

http://www.epa.gov/climatechange/emissions/index.html  
http://www.epa.gov/climatechange/kids/greenhouse.html