The Long and the Short of It - The Changing Arctic Environment: The Arctic Messenger - page 339

Stratospheric Ozone
Anticipation:
Inthelate1960sandearly1970s,atmosphericscientistswarnedthattheozonelayercould
be eroded by such substances as nitrogen oxides (NOx) released within the stratosphere
by supersonic aircraft and by the then-planned space shuttle. By 1973, it was known that
chlorofluorocarbon (CFC) gases (widely used as refrigerants and as spray propellants)
were ubiquitous in the atmosphere at surprisingly high concentrations. Almost immedi-
ately, laboratory studies showed that CFCs could be very effective at eroding the ozone
layer under the conditions that exist in the stratosphere. Environmental agencies began to
consider regulatory actions despite vigorous activity from lobby groups.
Perception:
In 1982, a massive springtime depletion of stratospheric ozone above Antarctica was re-
corded, covering a geographical area larger than that of the United States. In subsequent
years, the spring Antarctic ozone hole grew to up to 27 million square kilometres. Further
studies revealed widespread seasonal thinning of the ozone layer, particularly over the
Arctic.
Reaction:
This was very unusual because the first regulations to control CFCs as spray can propel-
lants (not as refrigerants) came into effect in the United States in 1979. In other words,
this was before it had been proven that the ozone layer was being significantly depleted.
Similar regulations quickly followed in other countries. Other uses of CFCs remained un-
regulated, but international political action was swift. In 1985, the Vienna Convention for
the Protection of the Ozone Layer (VCPOL) was negotiated and followed in 1987 by the
Montreal Protocol on Substances That Deplete the Ozone Layer. As of this writing, 197
countries have ratified it.