Ozone Layer Saved: Montreal Protocol Signs History
The Montreal Protocol, signed on September 16, 1987, committed nations to phasing out chlorofluorocarbons (CFCs) and other chemicals destroying the ozone layer. Scientists had discovered in 1985 that a "hole" in the ozone layer over Antarctica was growing each spring, allowing dangerous ultraviolet radiation to reach Earth's surface. The protocol was ratified by every member of the United Nations, making it the first international treaty to achieve universal ratification. By 2020, the ozone-depleting substance concentration in the atmosphere had dropped by 99%. NASA projects the ozone layer will return to 1980 levels by approximately 2066. The Montreal Protocol is widely considered the most successful international environmental agreement in history and prevented an estimated 2 million skin cancer cases per year.
September 16, 1987
39 years ago
Key Figures & Places
What Else Happened on September 16
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