Environmental Engineering Reference
In-Depth Information
of what is known as a framework or umbrella convention. It sets out such elements as aims
and objectives as well as methods of operation, such as decision making and procedures
whereby concrete actions can be undertaken. The “workhorses” of framework conventions
are their accompanying protocols. They spell out any legally binding obligations to imple-
ment the objectives of the convention and describe in detail the responsibilities of the par-
ticipating countries (parties). For the Vienna Convention, the “workhorse” is the Montreal
Protocol on Substances That Deplete the Ozone Layer. It was agreed on in September 1987
and entered into force in January 1989. At the time of writing, it has been ratified by all
197 countries that are parties to the Vienna Convention. In its original form, the protocol
stipulated that the production and consumption of compounds that deplete ozone in the
stratosphere (CFCs, halons, carbon tetrachloride andmethyl chloroform) were tobephased
out by 2000. (It was later accelerated to 1995.) Halons are unreactive gaseous compounds
of carbon and a halogen (five elements occupying Group VIIA of the Periodic Table).
They were used as fire suppressants, which included chlorine and bromine, while methyl
chloroform was used as a food and grain fumigant. Since 1989, the protocol has been
strengthenedthroughsevenrevisions,mostlyinresponsetonewscientificinformation,and
has taken on board actions on substances that in 1989 were not understood to be capable of
stratospheric ozone depletion. These include hydrochlorofluorocarbons (HCFCs), methyl
bromide and hydrobromofluorocarbons (HBFCs).
The catalyst that propelled the birth of the Montreal Protocol was no doubt the con-
tinuing stream of scientific reports that emphasized the urgent need for international con-
trols on ozone-depleting substances. The most influential was the Ozone Trends Panel or-
ganised by NASA. Its report released in 1988 concluded that ozone depletion was not
unique to the Antarctic but was occurring globally. The panel reported that between 1969
and 1986, stratospheric ozone had declined in winter by 6.25%, 4.7% and 2.3% at corres-
ponding latitudes of between 53° N and 64° N, 40° N and 52° N and 30° N and 39° N. At
the same time, it was shown that after lasting for eight weeks each spring, the Antarctic
hole slowly migrates as it dissipates. Its migration leads towards more populated areas, in-
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