Nearly six years after the United States helped negotiate it, the Senate has ratified a global climate treaty that would formally phase down the use of hydrofluorocarbons, or HFCs, industrial chemicals commonly found in air conditioners and refrigerators, insulating foams and pharmaceutical inhalers.

The Kigali Amendment, an addition to the Montreal Protocol climate treaty, aims to drastically reduce the global use of the compounds.

"This measure will go a long way to lowering global temperatures while also creating tens of thousands of American jobs," Senate Majority Leader Chuck Schumer said before Wednesday's vote, which passed 69-27.

HFCs were widely adopted in the 1980s and 1990s to replace another family of chemicals, chlorofluorocarbon, or CFCs, which damage the Earth's ozone layer. But after the switch, HFCs emerged as some of the most potent greenhouse gases, hundreds to thousands of times more potent than carbon dioxide. //

On the climate side, there is some evidence that commitments to cut back on the use of HFCs are not being followed. A study published in Nature Communications in 2021 found that atmospheric levels of the most potent HFC, HFC-23, should have been much lower than what scientists detected if China and India, countries responsible for manufacturing the majority of the compound that turns into HFC-23, had accurately reported their reductions.