English: The following description is based on the cited source - US Environmental Protection Agency (EPA, 2010): This graph shows changes in the annual greenhouse gas index (AGGI) between 1979 and 2008. The AGGI measures the levels of greenhouse gases in the atmosphere based on their ability to cause changes in the Earth's climate. It includes 17 greenhouse gases - among these are carbon dioxide, methane, chlorofluorocarbons (CFCs), and nitrous oxide. Changes in the AGGI reflect changes in the radiative forcing (i.e., the warming effect) of greenhouse gases in the atmosphere.

EPA (2010): "In 2008, the Annual Greenhouse Gas Index was 1.26, an increase in radiative forcing of 26 percent over 1990 [...] Carbon dioxide accounts for approximately 80 percent of this increase. Of the five most prevalent greenhouse gases shown in [the graph], carbon dioxide and nitrous oxide are the only two whose contributions to radiative forcing continue to increase at a steady rate. By 2008, radiative forcing due to carbon dioxide was 35 percent higher than in 1990. Although the overall Annual Greenhouse Gas Index continues to grow, the rate of increase has slowed somewhat over time. This change has occurred in large part because methane concentrations have remained relatively steady since 1990, and CFC concentrations are declining because most of their uses have been banned."