Greenhouse gases are components of the atmosphere that contribute to the Greenhouse effect. Some greenhouse gases occur naturally in the atmosphere, while others result from human activities such as burning of fossil fuel and coal.[1]Greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone.

Since the beginning of the Industrial Revolution, the concentrations of many of the greenhouse gases have increased as a result of human activity, resulting in such natural phenomenon as melting of polar ice caps, more severe weather patterns and changes in flora and fauna.