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The Ozone
Dramatic loss of ozone in the lower stratosphere over Antarctica was first noticed in the 1970s -
1974
Two United States chemists predicted that a class of chemicals called chlorofluorocarbons (CFCs), widely used in aerosol spray cans, would seriously damage the ozone layer. -
Montreal
In September 1987 an international meeting in Montreal created the world's first environmental convention. The Montreal Protocol set limits on the use of CFCs and related chemicals, including halons (widely used in fire extinguishers). Nations agreed to freeze production at 1986 levels and gradually cut it back, eventually eliminating use of the chemicals. -
'87
In September 1987 an international team returned from the Antarctic to reveal that the cause of the ozone hole was human-produced chlorine and bromine molecules escaping to the stratosphere and, under ultraviolet radiation, breaking down into 'free' atoms which can break ozone molecules apart. -
'95
Recognising their responsibility to the global environment they have agreed to halt production of the main CFCs from the beginning of 1995.