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In what year was the Montreal Protocol on ozone-depleting substances signed?

The Montreal Protocol was signed in 1987.

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  1. 1987 ✔
  2. 1972
  3. 1997

Why: Countries first agreed to cooperate on the ozone layer in the 1985 Vienna Convention. Two years later they signed the Montreal Protocol, which set the phaseout of ozone-depleting chemicals like CFCs.

Huh, didn't know that: In 1992 the parties moved up the schedule to end halon production by 1994 and CFC production by 1996 in developed countries.

The dad joke
What is the fruitiest subject at school? History, because it's full of dates!
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References

Answer: 1987. Countries first agreed to cooperate on the ozone layer in the 1985 Vienna Convention. Two years later they signed the Montreal Protocol, which set the phaseout of ozone-depleting chemicals like CFCs.

  1. International Treaties and Cooperation about the Protection of the Stratospheric Ozone Layer, US EPA www.epa.gov/ozone-layer-protection/international-treaties-and-cooperation-about-protection-stratospheric-ozone
    The original Montreal Protocol, signed in 1987, was the first step in international efforts to protect stratospheric ozone.
    Checked 2026-10-10.

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