|| Global Warming || Table of Contents ||
NOTE: "Human additions" represent such a small percentage of the total Greenhouse Effect (0.28%) that they are barely visible in this "pie chart" at the scale represented.
Atmospheric concentrations of the various greenhouse gases have been adjusted for heat retention potential of each. For example, the global warming potential (GWP) of various man-made chloroflourocarbons (CFC's) range between 1,300 and 9,300 times greater potency as greenhouse gases than CO2. Methane has a GWP of about 21 and nitrous oxide a GWP of about 310.
Comparing greenhouse gases by strict concentration only, the total human component is somewhere between 0.1% and 0.2%, depending on whose numbers you use. Adjusted for GWP, the total human contribution to Earth's overall greenhouse effect is about 0.28%.
For more information see the data behind the numbers .