360The world agrees to protect the ozone layer
On 16 September 1987, countries signed the Montreal Protocol, agreeing to phase out chemicals that were destroying the ozone layer, which shields life from the Sun's harmful ultraviolet rays. It became the first UN treaty signed by every country in the world. The ozone layer is now slowly healing and is expected to recover by about 2066.
In 1974, the chemists Mario Molina and Sherwood Rowland warned that chlorofluorocarbons, or CFCs, used in fridges and aerosol sprays, could destroy ozone high in the atmosphere.
In 1985, British Antarctic Survey scientists reported a large seasonal 'hole' in the ozone layer over Antarctica. The discovery alarmed governments.
On 16 September 1987, countries meeting in Montreal signed a protocol to cut CFC production. Later amendments brought in a full phase-out, with help for developing countries to switch to safer chemicals.
Every country has since joined. Scientists say the ozone layer is recovering, and the treaty has also helped slow climate change, since many of the banned chemicals are powerful greenhouse gases. 16 September is now World Ozone Day.
- 1974
- Molina and Rowland's warning
- 1985
- The Antarctic ozone hole is reported
- 16 September 1987
- The Montreal Protocol is signed
- 1995
- Nobel Prize in Chemistry for ozone research
Sources: UN Environment Programme · NASA · Britannica.