1B. The Main Greenhouse Gases

The tables below present characteristics of seven major greenhouse gases. The Global Warming Potential (GWP) indicates the radiative effect of a greenhouse gas, while the atmospheric lifetime expresses the "burden" of a specific greenhouse gas after taking into account global sink availability.

Greenhouse Gas	Chemical Formula	Anthropogenic Sources	Atmospheric Lifetime¹ [1](years)	GWP² [1] (100 Year Time Horizon)
Carbon Dioxide	CO₂	Fossil-fuel combustion, Land-use conversion, Cement Production	variable¹ [1]	1
Methane	CH₄	Fossil fuels, Rice paddies, Waste dumps	12¹ [1]	23
Nitrous Oxide	N₂O	Fertilizer, Industrial processes, Combustion	114^{1 [1]}	296
CFC-12	CCL₂F₂	Liquid coolants, Foams	100	10600
HCFC-22	CCl₂F₂	Refrigerants	11.9	1700
Perfluoroethane	C₂F₆	Aluminum smelting, Semiconductor manufacturing	10000	11900
Sulfur Hexaflouride	SF₆	Dielectric fluid	3200	22200

	Pre-1750 Tropospheric Concentration^{3 [1]}(parts per billion)	Current Tropospheric Concentration⁴ [1] (parts per billion)
Carbon Dioxide	280000^{5,6,7 [1]}	377700^{6 [1]}
Methane	730 / 688⁷ [1]	1847 / 1730^{8 [1]}
Nitrous Oxide	270^{7,9 [1]}	319 / 318^{8 [1]}
CFC-12	0	.545 / .542^{8 [1]}
HCFC-22	0	.174 / .155^{8 [1]}
Perfluoroethane	0	.003^{9 [1]}
Sulfur Hexaflouride	0	.00522

Source of graphical information and notes:
Blasing, T.J. ad K. Smith 2006. "Recent Greenhouse Gas Concentrations." In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Cetner, Oak Ridge National Laboratory, US Department of Energy, Oak Ridge, TN, USA. http://cdiac.ornl.gov/pns/current_ghg.html [2]

Click here to print this page and corresponding notes. [3]

Back to The Physical Basis of Global Warming Home [4]

Back to Facts and Figures Home [5]