The Montreal Protocol protects ozone

Chlorofluorocarbons were widely used in refrigeration, foams and other industrial processes. Researchers investigated their atmospheric behavior and proposed that released chlorine could destroy stratospheric ozone. Measurements and chemistry accumulated, while pronounced Antarctic changes drew international attention. Governments compared observations with industrial uses and alternatives, and producers assessed conversion. The Vienna Convention of 1985 established cooperation in research, observation and information exchange; subsequent negotiations addressed controls on production and consumption.

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Parties adopted the Montreal Protocol in September 1987, specifying substances, baselines, phased limits and reporting of production and consumption. Developing countries received different implementation conditions, and provisions allowed controls to respond to new knowledge. The protocol entered into force in 1989. Later meetings adopted amendments and adjustments covering additional substances and stronger reductions. Licensing, statistics, trade administration and industrial measures translated international obligations into practical national activity.

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Implementation required equipment changes, alternative materials, safety practices and training. The Multilateral Fund, established in 1990, supported conversion in developing countries and connected international finance with firms and authorities. Researchers continued measuring ozone and controlled substances to assess progress and further needs. Refrigeration service, manufacturing, customs and laboratories each performed different tasks. Cooperation entered ordinary industrial operations, while technical change, monitoring and implementation experience informed continuing updates to the agreement.

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