Greenhouse Gases

Greenhouse gases have been defined by the Intergovernmental Panel on Climate Change (IPCC) as “those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of infrared radiation emitted by Earth's surface, the atmosphere and clouds” (IPCC, 2007, p. 816). By the end of the 20th century, the rising atmospheric concentration of greenhouse gases had created a situation of global warming so severe that the problem became a test case in the capacity of global governance to deal with significant planetary environmental problems.

This definition given by the IPCC not only refers to the interplay of specific aerosols within the atmosphere, but it deals with one of the most urgent issues of global policy. Ranking high in media coverage in the wake of Al Gore's film An Inconvenient Truth in 2006, scientific warnings can be dated back as early as the mid-1960s, when Roger Revelle (together with Charles Keeling, a pioneer in measuring emission trends) addressed the U.S. president's Science Advisory Committee. Summing up his findings, he concluded, “Consequently an increase of atmospheric carbon dioxide could act much like the glass in a greenhouse, to raise the temperature of the lower air” (Revelle, 1965, p. 112).