Ozone layer - recovering!
- The ozone layer is that part of the atmosphere which contains relatively high concentrations of ozone (O3)
- The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson
- Ozone in the earth's stratosphere is created by ultraviolet light striking oxygen molecules
- The ozone layer can be depleted by free radical catalysts (such as nitric oxide (NO), hydroxyl (OH), and atomic chlorine and bromine)
- There are natural sources (such as sulfurous gases emitted by some volcanoes) for all of these compounds
- Concentrations of Cl and Br have increased in past 30 years due to organohalogen compounds (such as CFCs)
- Ozone levels, over the northern hemisphere, have been dropping by 4% per decade and over 5% over the polar regions
- In 1976, based on a report by the U.S. National Academy of Sciences which showed scientific evidence on the ozone depletion hypothesis, a few countries, including the United States, Canada, Sweden, and Norway, moved to eliminate the use of CFC's in aerosol spray cans
- In 1985 20 nations, including most of the major CFC producers, signed the Vienna Convention which established a framework for negotiating international regulations on ozone-depleting substances
- Later that year, a reduction of about 70% in the ozone layer (the ozone hole) was discovery over Antarctica
- Governments quickly enacted an international treaty, called the Montreal Protocol, to ban ozone-destroying gases such as CFCs then found in aerosol cans and air conditioners.
- In 1987, 43 nations signed the Montreal Protocol - agreeing to freeze production of CFCs at 1986 levels and to reduce production by 50% by 1999
- Sri Lanka has signed all these protocols
- The ozone hole over Antarctica has not improved
- Ozone layer around the rest of the planet has stopped depleting
- Wikipedia Article about Ozone Depletion
- Wikipedia Article about the Ozone Layer
- Wikipedia Article about the Montreal Protocol
- List of countries who signed the Montreal Protocol and subsequent protocols
- NASA Article about the Ozone layer recovering
- UNDP Sri Lanka Web Site: Montreal Protocol
- National compliance action plan for Sri Lanka
