Human activities are increasing the worldwide atmospheric concentrations of chlorofluorocarbons, carbon dioxide, methane, and several other gases. A growing body of scientific evidence suggests that, if these trends continue, stratospheric ozone may decline and global temperature may rise. Because the ozone layer shields the earth's surface from damaging ultraviolet radiation (UV), damage to the ozone layer could harm future crop yields, destroy materials, and place additional stress on aquatic plants and animals. A global warming from the "greenhouse effect" could threaten human health and cause melting of the polar ice caps. Precipitation and storm patterns could change, and the level of the oceans could eventually rise. These possibilities emphasize the increasing danger of a disappearing ozone layer. If action is not taken now, people will soon suffer the serious consequences.
The ozone in the uppermost part of the atmosphere, the stratosphere, is created by ultraviolet radiation. Oxygen (O2) is converted to ozone (O3) and back to 0 by many photochemical reactions that take place in the stratosphere (Council on Environment, 1986, p. 7). Chlorofluorocarbons and other gases released by human activities could alter the current balance of creative and destructive processes. Because CFCs are very stable compounds, they do not break up in the lower atmosphere, known as the troposphere (Committee on the Atmosphere..., 1981, p. 13). Instead, they slowly migrate to the stratosphere, where ultraviolet radiation breaks them down, releasing chlorine atoms that act gradually to decrease the average concentration of ozone by means of catalytic chain reactions (Council on Environment, 1986, p. 23).
The ozone layer itself is composed of a highly reactive, poisonous form of oxygen with the formula 03, having a chlorinelike odor detectable by most people (Council on Environmental Quality, 1982, pp. 32, 37). Ozone is produced natu...