Ozone Depletion

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The term ozone is sometimes used interchangeably to discuss different phenomena such as ground level pollution called smog along with the chemicals which constitute the upper layer of the atmosphere.

Basically ozone is the simple combination of three oxygen molecules (O₃), and ozone depletion refers to the chemically induced breakup of those molecules in the stratosphere, the area of the atmosphere about six miles above the earth.

During the 1970s, scientists began expressing concerns about the effects that man-made chemicals such as Chlorofluorocarbons (CFCs) had on the ozone layer. They showed that these chemicals interact with O₃ and break off one of the oxygen molecules. The replacement of O₃ with O₂ and free O molecules meant an increase in the sun's ultraviolet radiation (UV-B) reaching the earth, and consequently increasing the possibility of skin cancer and other dangers to human health.

By the middle of the 1980s states around the world agreed to regulate the use of ozone depleting chemicals and codified that agreement in the form of multilateral treaties. The Ozone Secretariat is the formal body for coordinating state activity.

While the Ozone treaties have been celebrated as models of international environmental cooperation, they have also shown the limits of international cooperation. Because CFCs and other ozone depleting substances are used for popular consumer items such as refrigeration and air conditioners, underground or illegal trade in ozone depleting substances picked up where the legal trade left off.

The result is that after twenty plus years of multilateral activity, ozone depletion is still a problem. In November 2008, scientists at NOAA said, "The ozone hole over Antarctica, which fluctuates in response to temperature and sunlight, grew to the size of North America in a one-day maximum in September that was the fifth largest on record, since NOAA satellite records began in 1979."

Assuming that the illegal trade in ozone depleting chemicals can be effectively dealt with and states maintain their current reductions in the legal use of these chemicals, scientists predict that it will take fifty years or more for the problem to be resolved.

NASA scientists produced a nice video explaining the ozone depletion problem.

© 2001-2009. Patricia A. Michaels