ABSTRACT
One of the ironies of contemporary technological civilization is that some technological advances, which seem ideal for their immediate purposes, turn out to have unsuspected side effects with potentially serious consequences for society. A recently discovered example is the potentially serious damage to the earth’s protective ozone shield from inert chlorofluorocarbons (CFCs) used as aerosol propellants, refrigerants, solvents, foam-blowing agents, plastics, and resins. It is also the case that the CFCs could have significant impacts on the global – climate. The technological attraction of the CFCs lies in the combination of qualities which makes them so ideal for their immediate use by society—chemical stability, noncorrosiveness, noninflammability, nontoxicity, and low cost. However, the very stability which makes them so ideal for their purposes permits them to remain inert until they migrate from the troposphere (the lower atmosphere) to the stratosphere, where a complex set of photochemical reactions culminates in the destruction of stratospheric ozone. In addition, during the long period when the CFCs reside in the troposphere, they contribute to the “greenhouse effect” by absorbing the emissions of infrared radiation from the surface of the earth, thus contributing to a rise in temperature. This is in addition to a similar greenhouse effect expected from increased carbon dioxide (CO) emissions. Although the strength and magnitude of the complex physical linkages between these processes have not been precisely measured, the accumulating evidence indicates that the use of CFCs has damaged and is continuing to damage the earth’s ozone shield. Additional, though less conclusive, evidence suggests that with damage to the ozone layer, increased amounts of biologically damaging ultraviolet radiation reach the earth’s surface, and this is likely to increase the incidence of both melanoma and nonmelanotic skin cancer for human beings, and to injure crops, livestock, materials, and ecosystems. Further, on a molecular basis, it appears that CFCs are about 100,000 times more effective than CO2 as contributors to the greenhouse effect. Thus, small amounts of CFCs in the troposphere correspond, in impact, to much greater amounts of CO2. Consequently, it appears that by the year 2000, CFCs may well contribute as much to global warming as will CO2. This prospective impact probably deserves more recognition than it has received.
