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A treaty adopted 35 years ago and meant to solve an entirely different problem is also protecting the climate. And with bipartisan support from the Senate and President Joe Biden’s Oct. 26 signature, the U.S. became the world’s 139th nation to adopt a key amendment to that agreement — the first time the U.S. has joined a legally binding global measure specifically to combat climate change.

Global warming was on the back burner in 1985 when scientists from the British Antarctic Survey found a gaping hole in the planet’s stratospheric ozone layer. A natural feature of the atmosphere, the ozone layer is located between about 10 to 25 miles above Earth’s surface. It shields the planet from the sun’s ultraviolet radiation, which is harmful in large doses to our skin and to myriad other aspects of plant and animal life.

Researchers rapidly pinned down the cause of the ozone destruction: chlorofluorocarbons, known as CFCs, which are chemicals used as refrigerants and to manufacture aerosol sprays and other materials. CFCs had been recognized for years as a threat to the ozone layer, but the ozone hole found in the mid-1980s was far worse than anything expected by that point.

By 1987, diplomats had crafted a treaty known as the Montreal Protocol to fix the problem. It was an immense success, ratified by every member state of the United Nations.

There was a major catch, though.

Both CFCs and their leading replacements – hydrofluorocarbons, or HFCs – trap heat in the atmosphere, causing global warming.  


Enter the Kigali Amendment. 

Adopted at a United Nations meeting held in the Rwanda capital in October 2016, it uses a variety of policy approaches to throttle back on both the production and consumption of HFCs. The amendment has put the world on track to eliminate more than 80% of HFCs by midcentury. 

One reason the Kigali Amendment passed the Senate with bipartisan support (69-27, including 21 of the chamber’s 50 Republicans) is that national action on HFCs along the lines of Kigali was already in gear. The pandemic stimulus bill of late 2020 specified an 85% cut in HFC production by 2030. Many lawmakers, especially those from states with major chemical manufacturing, had recognized that cutting HFCs made sense. For one thing, nations that have not ratified the amendment cannot trade HFCs with those that have. 

Author(s): Bob Henson

Publication Date: 3 Nov 2022

Publication Site: Yale Climate Connections