The Montreal Protocol Protection of Ozone and Climate

David W. Fahey


The Montreal Protocol is an international treaty that has reduced the atmospheric abundances of ozone-depleting substances (ODSs) through regulations on national production and consumption of these substances. The regulations have succeeded in protecting the ozone layer from unchecked future emissions of ODSs. As such; the Protocol is perhaps the most successful example of international cooperation on the environment. ODSs are also greenhouse gases that have the potential to change global climate when they accumulate in the atmosphere. Thus; the actions of the Montreal Protocol to protect ozone have also protected future climate and; hence; have provided a dual benefit to society. As for the long-term substitutes for ODSs;hydrofluorocarbons (HFCs) do not destroy ozone - but they are greenhouse gases. The increases in HFC emissions that occur in response to Montreal Protocol regulations could be substantial by the mid twenty-first century;offsetting the climate protection already achieved by the Protocol. Avoiding these projected HFC emissions stands as a significant opportunity for international cooperation on protecting future climate.

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