I think that pollution is a serious and growing problem throughout the world today. Pollution is the contamination of the earth's environment with materials that interfere with human health, the quality of life, and natural functioning of living things and their surroundings. Although some environmental pollution is a result of natural causes, most of it is caused by human activities; therefore I believe that humans have created a problem which should be taken care of before other things. There are two main categories of polluting materials, or pollutants, biodegradable and nondegradable. Biodegradable pollutants are materials, such as sewage, that rapidly decompose by natural processes. These pollutants become a problem when added to the environment faster than they can decompose. Nondegradable pollutants are materials that either do not decompose or decompose very slowly into the natural environment. Once contamination occurs, it is difficult or impossible to remove these pollutants from the environment.
Pollution has a dramatic effect on natural resources. Ecosystems such as forests, wetlands, coral reefs, and rivers perform many important services for the earth's environment. They enhance water and air quality, provide habitat for plants and animals, and provide food and medicines. Any or all of these ecosystem functions may be seriously impaired or destroyed by pollution. Moreover, because of the complex relationships among the many types of organisms and ecosystems, environmental contamination may have far-reaching consequences that are not immediately obvious or easy to predict. For example, the use of aerosols, which contain chemicals called CFCs, can damage the ozone layer. Destruction of the ozone layer is predicted to cause increases in skin cancer and cataracts, damage to certain crops and to plankton and the marine food web, and an increase in carbon dioxide due to the decrease in plants and plankton.