US signs off on deal to slash powerful greenhouse gases

Amendment to a global treaty from the 1980s that helped repair hole in the ozone layer

In a major win for climate advocates, the United States Senate has ratified the Kigali Amendment, which experts say could significantly reduce planetary warming in the coming decades.

The vote — signed off by a large bipartisan group of senators — finalises the US agreement to the deal made by former President Barack Obama in 2016.

The amendment will phase out the worldwide use of hydrofluorocarbons (HFCs), chemicals often used in refrigeration and air conditioning. HFCs are an extremely potent greenhouse gas with the ability to heat the planet thousands of times more than carbon dioxide (CO2) on a per-pound basis.

“The United States is back at the table leading the fight against climate change,” President Biden said in a statement on the amendment’s passage.

The deal is an amendment to the Montreal Protocol from the 1980s, which helped fix the hole in the ozone layer by phasing out a group of ozone-depleting chemicals called chlorofluorocarbons (CFCs) once frequently used in refrigeration and aerosol sprays.

Over time those chemicals were replaced with HFCs which, while not damaging to the ozone layer, can be powerful planet-warming gases. Many HFCs, per pound, can heat the planet between 100 and 11,000 times more than CO2, the most common greenhouse gas which is driving the climate crisis.

Since the agreement was an amendment to a global treaty, it required more than two-thirds of Senators to vote yes in order to pass under the US Constitution. The final vote was 69-27 in favour, with some Republicans joining Democrats to vote yes.

The agreement will phase out HFCs over the next few decades worldwide. Experts have said that this alone could prevent up to 0.5 degrees Celsius (0.9 degrees Fahrenheit) of warming by 2100.

The 2015 Paris Agreement has tried to limit planetary warming to around 1.5C – and the climate crisis has already pushed temperatures 1.1-1.2C above 19th-century averages.

HFCs will be replaced by alternative chemicals over the next few decades, with faster timelines for some wealthier countries.

Many US business interests supported the amendment, which likely helped create a more bipartisan consensus on the agreement. The American Chemistry Council, a trade group for US the chemical industry, put out a statement on Wednesday cheering the passage, saying that it will help create manufacturing jobs.

A number of industry groups, collected with the US Chamber of Commerce, had written a letter urging the Senate to pass the amendment back in June.

Wednesday’s vote was also applauded by environmental groups pleased with the climate implications.

“The Senate’s bipartisan vote today makes the United States a full partner in the global phasedown of the powerful climate pollutants called hydrofluorocarbons that are helping drive severe storms, floods, heat and wildfires across the U.S. and around the world,” the non-profit Natural Resources Defense Council’s David Doniger said in a statement.

“With bipartisan support, the Senate has committed to international climate policy that phases down a super-pollutant while bolstering U.S. manufacturing,” Carol Andress from the non-profit Environmental Defense Fund said in a statement. “The United States already leads the world in making climate-friendly alternatives to HFCs, and this move helps eliminate potential barriers to export them.”

In addition to the US, 136 other countries, plus the European Union, have ratified the agreement.