{Last week, nearly 200 countries found a compromise that will phase out super-polluting HFC gases. Some say the US Senate could slow that progress, but many observers say that the United States – and the world – is on the right track.}

The Kigali agreement to phase out a particularly potent greenhouse gas is a big deal for climate protection efforts and international cooperation more broadly.

The agreement commits almost 200 countries to reducing their use of hydrofluorocarbons (HFCs) over the next 30 years. These compounds – most often used in refrigerators and air conditioners – are the world’s fastest-growing greenhouse gases. The international community agreed that cutting the artificial pollutants, which have a warming effect 1,600 times more powerful than carbon dioxide on average, would be a straightforward step toward meeting the Paris Agreement goal to keep global temperatures from rising more than 2 degrees Celsius above preindustrial levels.

Now, with the meetings in Kigali concluded, attention has turned to implementation. One possible obstacle to curbing HFC use: the US Senate. If the Senate is required to approve the phase-out, some say they would refuse, perhaps leading other countries to question their commitments too. But others say the United States is fully committed to implementing the agreement, while technological transformation makes phasing out the gases less of a burden for developing countries.

That countries are willing to enter into a legally binding agreement about HFCs signals the depth of their commitment to addressing climate change issues. And its success could pave the way for further progress, observers say.

“This is the biggest step that could be taken and now has been taken in the year following the Paris Agreement. It really continues … the international momentum,” David Doniger, director of the Climate and Clean Air Program at the Natural Resources Defense Council, tells The Christian Science Monitor. “It’s an important statement that the level of cooperation is high. We’re in a virtuous circle — countries saying, ‘I will if you will,’ ” he continues.

Mr. Doniger sees the United States at the forefront of this positive international movement. He points out that the United States was one of those pushing the hardest for some kind of agreement on HFCs. “I have no doubt that the United States will become a party to Kigali,” he underlines.

For Steve Seidel, senior advisor at the Center for Climate and Energy Solutions, US support for the Kigali Agreement is borne out in the actions the country is already taking to reduce its use of HFCs.

“We’ve already seen alternatives developed in all the major use categories,” including refrigerators and air conditioners, he says in a phone interview with the Monitor. Often, these alternatives are not only better for the environment but more efficient. As a result, “the HFC amendment has brought very broad support from industry and the environmental community,” he says.

It is unclear whether the Senate will be asked to review the Kigali Agreement. “We will need to examine the content and the form of the agreed amendment, as well as relevant practice, in order to determine the appropriate approval process,” Emily White, a spokeswoman for the State Department, told Climate Central on Monday.

Nigel Purvis, chief executive officer of Climate Advisers and a former State Department treaty lawyer, says that such approval may not be necessary.

“It’s a well established principle of U.S. law that the President can approve, without further Congressional review, certain international agreements that fall under a treaty already approved by the Senate,” he wrote in an emailed statement to the Monitor. The Montréal Protocol, to which the Kigali Agreement is an amendment, was overwhelmingly approved by the Senate in 1988, with a vote of 83 to 0.

“Our Senate is always a challenge in ratifying environmental treaties these days,” Mr. Seidel says, though he notes that the Senate has a long history of ratifying similar amendments. And politicians on both sides of the aisle have increasingly shown themselves open to cooperation on climate issues. Last year, four Republican senators formed a working group to discuss environmental protection and clean energy initiatives. A group of Democratic and Independent senators signed a letter calling for strong action on HFCs in Kigali.

With or without Senate approval, both Doniger and Seidel believe progress to phase down HFCs will continue. Doniger says the international community has experience of phasing out any number of chemicals, and will be able to do so again. In the process, countries will get technical support from the World Bank, the UN Development Program, and the UN Environment Program. Financial assistance will come from the Montréal Protocol’s Multilateral Fund, which helps developing countries cover the cost of phasing out chemicals.

Seidel explains that technological change to support the drawdown in HFCs is already happening in developing countries like China and India. The amendment “builds on market forces that are beginning to take hold.” This, coupled with the pressure developing states say they are feeling from climate change, means ratification may be more of a formality on the way to eliminating HFC gases.

“The process is underway and will continue regardless of when ratification and entry into force occurs,” Seidel says.

Secretary of State John Kerry delivers a speech to the 28th Meeting of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer, in Kigali, Rwanda on Oct. 14.