Many people confuse the two environmental issues linked to the atmosphere, thinking that global warming is somehow linked to the depletion of ozone in the upper atmosphere. This is incorrect, they are separate problems with different causes, effects and solutions.
The ozone layer is a layer of gas high in the Earth’s atmosphere which protects us from the harmful effects of ultraviolet radiation from the Sun. In the 1980’s it was found that the ozone layer was thinning, indeed one area directly over the South Pole was found to be essentially ozone free – the much talked about ‘hole in the ozone layer’. This has continued to enlarge and other ‘holes’ can be observed throughout the atmosphere.
It was discovered that the main pollutant responsible for the depletion of ozone was chlorofluorocarbons (CFC’s), chemicals that had been first manufactured in the 1920’s. The main use of of these was for refrigeration but they were also used as propellants in aerosol cans and in cleaning processes in the electronics industry.
Gradually, the use of CFC’s became more widespread. Then, as they were released into the atmosphere, they slowly made their way higher in the air, taking five to seven years to get there. When they reach the ozone layer, a single CFC molecule can react with and destroy as many as one hundred thousand ozone molecules in the century or so that they remain there.
CFC’s are now banned but the problem will be with us well into the 21st century and maybe beyond, since CFC molecules are very stable.