The ozone layer should recover by 2066

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The ozone depletion season peaks from September to October and this year saw the seventh smallest hole since the recovery point began in 1992, a few years after the Montreal Protocol was signed. This is a landmark international agreement on the gradual phasing out of ozone-depleting chemicals.

The average monthly diameter of the ozone layer was 20 million square kilometers this year. The improvement is due to a combination of continued declines in harmful chlorofluorocarbon chemicals along with an unexpected infusion of ozone carried by air currents from northern Antarctica.

In past years, NASA and NOAA have reported assessments of ozone holes using a time frame of 1979. At that time, scientists began monitoring ozone levels in Antarctica using satellite data. Paul Newman who is NASA's team leader and chief scientist at Goddard Space Center in Maryland notes that improvements over the past two decades show that international efforts to limit ozone-depleting chemicals are working.

The ozone-rich layer high in the atmosphere acts as a planetary solar screen, helping to protect us from harmful ultraviolet radiation from the Sun. Ozone-depleted areas will allow more radiation to penetrate resulting in increased incidences of skin cancer and cataracts.

By the mid-1980s the ozone layer was so depleted that by early October each year a large portion of the Antarctic stratosphere was essentially ozone-free. Sources of harmful CFCs included coolants in refrigerators and air conditioners as well as aerosols in hair sprays.

Today, it is certain that the ozone hole is slowly being closed, but it will take several more decades for ozone levels to return to pre-chemical and CFC levels.

Source:NASA/Editorial