In September the world celebrated the 25th anniversary of the Montreal Protocol, which controls and phases out substances that deplete the ozone layer. The Protocol is the operative arm of the Vienna Convention for the Protection of the Ozone Layer, and every country in the world has signed and ratified it. As a country close to the springtime Antarctic ozone hole (http://ozonewatch.gsfc.nasa.gov/), and a good global citizen, Australia has put a lot of effort into the development and implementation of this multinational environment agreement.
The Earth’s ozone layer, which protects us from harmful ultraviolet radiation, has been under threat from chlorine atoms released by chlorofluorocarbons (CFCs) and related anthropogenic chemicals. The CFCs are almost gone now, and the Protocol has in place a phase-out schedule for their successors, the hydrochlorofluorocarbons (HCFCs), the most common of which in our daily lives is HCFC-22 (chlorodifluoromethane) which is the working fluid in home air conditioners. Other ozone-depleters being phased out under the Montreal Protocol are the halons, which are used in fire protection, and the fumigant methyl bromide.
If all countries stay on-track, the ozone layer will recover by the middle of this century. So what’s next for the world’s...
