Greenhouse Effect

A Natural Process

The greenhouse effect is a complicated natural process that occurs in the earth's atmosphere, which has four major layers. The Troposphere is the thick layer extending from the surface of the earth to about 7 miles (11.3 kilometers). It holds the air life on earth breathes and most of the clouds. The Stratosphere extends from the top of the troposphere to about 30 miles (48 kilometers) above the surface of the earth. It has some high flying clouds, but its upper portion is the location of the ozone layer. The Mesosphere is the third layer of the earth's atmosphere. It extends to about 50 miles (80 kilometers). The final layer is the Thermosphere. The atmosphere is extremely thin, and extends to about 600 miles (965 kilometers) above the surface of the earth. Beyond is empty space.

Solar energy striking the earth is composed of more than just visible light. In the electromagnetic spectrum, the radiation leaving the surface of the sun is composed of short-wave X-rays and gamma rays. Gamma rays are deadly to humans for even a short period of time. However, these forms of radiation are absorbed in the Thermosphere by the time they have penetrated the atmosphere to a depth of about 100 miles (160 kilometers) above the earth's surface.

Ultraviolet (UV) waves are next to X-rays and gamma rays in wavelength. These wavelengths extend across the electromagnetic spectrum to violet light in the visible spectrum. UV waves are dangerous to living things. They cause sunburn and can kill plankton in the oceans. They are absorbed in the top of the Mesosphere by ozone. Without the ozone layer there would be an increase in damage to eyes and skin cancers.

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