Ozone layer depletion and global warming are two terms that most people have heard throughout their lives, but may have little insight into the difference between the two. Both stem from naturally occurring processes that go bad with the creation of particular human induced chemicals, but the sources of the types of problems they create are very different.

The ozone layer is a thin layer of ozone molecules in the stratosphere. It absorbs ultraviolet light and converts it to infrared radiation. The layer effectively screens out 99% of the ultraviolet light coming in to the Earth. Humans can have a major impact on how successful the ozone layer is. The use of chlorofluorocarbons (CFC’s) in things like spray-can propellants and coolants send the CFC’s to react with the ozone in the stratosphere, and destroy the ozone. This has led to a hole in the ozone layer over Antarctica the size of North America. The hole affects people close to it, and all over the world with skin cancer, and potentially worse problems.

Global warming is the product of the greenhouse effect in action with increasing carbon dioxide and other “greenhouse gases”. Carbon dioxide acting like glass in a greenhouse causes the greenhouse effect by permitting visible light to penetrate but impeding the escape of heat. The increase of fossil fuel burning is the largest source of the increase of global warming. The long-term results of global warming could be the rising of the oceans, spread of diseases, melting polar caps, extinction of wildlife, and the starvation of millions of humans. The worldwide Kyoto Conference aims to stabilize greenhouse gas emissions in the atmosphere to prevent these potential disasters.

In America, the use of CFC’s has been banned. Worldwide, the use has dropped dramatically. However, the ozone hole continues to affect millions of people. On the other hand, carbon dioxide emissions continue to increase at the rate of 1.5 parts per million per year. An international agreement such as the Kyoto Protocol seems to be the only hope for the world to cut down these emissions.

Sources: Stanitsky, Conrad L., et al. Chemistry in Context. New York: McGraw-Hill, 2000. Chiras, Daniel D. Environmental Science: Action for a Sustainable Future. Redwood City, California: Benjamin Cummings P, 1994.