Ozone

In the stratosphere, ozone, is not only a greenhouse gas but also shields us from ultraviolet light. There has been a loss of stratospheric ozone, especially in the Antarctic region. During the Antarctic springtime, ozone levels drop to about 50 percent of normal and then recover during the rest of the year. This ozone depletion is anthropogenic and is due to chemical reactions between ozone and either chlorofluorocarbons (CFCs) or nitrous oxide.

In the troposphere (atmosphere closest to the earth), ozone is a greenhouse gas and is released during the combustion of fossil fuels. It is increasing in concentration, especially in the Northern Hemisphere because this is where most fossil fuels are burned. Tropical forests act as a sink (reservoir) for ozone, so their destruction would increase tropospheric ozone levels.

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