What are the main greenhouse gases?

The main greenhouse gases are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and fluorinated gases. Fluorinated gases are the most important greenhouse gas group because of their strength or global warminfg potential. Carbon dioxide is the greenhouse gas with the highest amount of emissions by volume.

The main greenhouse gases are: ¹

Figure 1:

Source: Inventory of U.S. Greenhouse Gas Emissions and Sinks (2008), EPA.

• Carbon Dioxide (CO₂): Carbon dioxide enters the atmosphere through the burning of fossil fuels (oil, natural gas, and coal), solid waste, trees and wood products, and also as a result of other chemical reactions (e.g. cement production). Carbon dioxide is also removed from the atmosphere (or "sequestered") when it is absorbed by plants as part of the biological carbon cycle.
• Methane (CH₄): Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock, certain agricultural practices and by the decay of organic waste in municipal solid waste landfills.
• Nitrous Oxide (N₂O): Nitrous oxide is emitted during agricultural and industrial activities, as well as during the combustion of fossil fuels and solid wastes.
• Fluorinated Gases or High GWP gases: Hydrofluorocarbons(HFCs), perfluorocarbons(PFCs), and sulfur hexafluoride(SF₆) are synthetic, powerful greenhouse gases that are mostly emitted from the creation and/or use of refrigerators, air conditioning systems, foams and aerosols. These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are referred to as High Global Warming Potential gases.

To learn more about High Global Warming Potential gases click here

¹http://epa.gov/climatechange/emissions/index.php