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Invisible in the stratosphere, 20 to 50 kilometers above the Earth, hovers a delicate girdle of ozone (O3). This ozone girdle protects life on Earth by intercepting 99% of the harmful incoming solar ultraviolet radiation. Terrestrial life depends on this protective girdle, for even small doses of ultraviolet radiation cause burns, engender cancer, and lethal mutations in virtually all life forms. Ozone works hard to protect life on Earth. When ultraviolet radiation strikes stratospheric ozone molecules, they burst apart. The pieces then quickly recombine to form new ozone molecules. In this process, the ultraviolet radiation converts into harmless heat energy. The ozone layer is thus self-renewing and helps maintain the temperature of the upper stratosphere. 20,000 times as efficient at absorbing heat as carbon dioxide, each CFC(chlorofluorocarbon) molecule contributes to the greenhouse effect and speeds up global warming. Moreover, experts estimate that 3% to 5% of the ozone layer has already been destroyed by CFCs. Most governments have agreed to cut back on nonessential Freon use. They further must scrupulously oversee the careful handling and recycling of the CFCs already in use. As citizens of the planet, we should urge our governments to mandate unilateral phase outs of CFCs while actively seeking international agreement. |
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