CFCs, another name for chlorofluorocarbons, are synthetic gases, produced only in chemical factories. CFCs are chemically very stable - at least until they get to the stratosphere where they react effectively to destroy the ozone layer. CFCs are not only bad for the stratospheric ozone layer, they are very powerful greenhouse gases as well. Even though CFC-11 and CFC-12 are measured in very low concentrations - 230 parts per trillion for CFC-11 in 1986 - their IR absorption properties are very strong. V. Ramanathan explained at Senate hearings that a single CFC-11 molecule has the same greenhouse effect as 10,000 molecules of CO2.[Senate Comm: Energy and Nat. Resources, 11/9/87]
CFC gases have been added to the atmosphere since 1930, when they were first commercially produced for refrigerators. In the past few decades, their use has grown rapidly, with measured increase rates in the atmosphere of as high as 12% for CFC-113. CFC-11 and CFC-12 are increasing at a rate of 5 percent per year. CFCs are used for refrigeration, air conditioning, fire extinguishers, cleaning solvents, and as a blowing agent for rigid plastic foams. While these gases have been around for only 60 years, they have been added to the atmosphere at such rapid rates so as to be very important greenhouse gases. Christopher Flavin, of the Worldwatch Institute, reports that CFC gases already account for 25 percent of the greenhouse effect.
One problem with regulating CFC use is that CFC-22 has been suggested as a replacement for ozone damaging CFC-12 in many applications, yet CFC-22 has strong greenhouse absorption properties.
More information on CFCs is available under the "CFC Destruction of the Ozone Layer" section. ***
