More than 100 countries have ratified the Kigali Amendment, making it legally binding. The United States is not among them.
The White House has said little about why it has not ratified the Kigali document, despite urging by Republican senators.
"It's very important that other countries, especially the bigger countries, commit to [the Kigali Amendment]," said RIVM's Velders. "A lot of countries look to Europe, the United States and Japan to lead initiatives. It's important that they lead by example. Otherwise, for other developing countries, it's quite easy for them to say, 'Well, why should we worry if the most polluting countries don't comply with it?' "The U.S. Environmental Protection Agency under President Donald Trump has rolled back previous steps to regulate HFCs and dozens of other environmental regulations, though courts have struck down some of these measures.
The new proposed legislation would require an 85% reduction in HFC production and use by 2036. HFCs would still be allowed in "essential" products that don't have available substitutes. The list includes defense sprays such as bear repellents, medical inhalers and mission-critical military uses.
"At the end of the day, whether we ratify Kigali and have a plan to phase out HFCs, or whether we just decide to phase out HFCs, either way, it's a win for the planet if we can work to reduce HFCs," said Caitlin McCoy, staff attorney at the Harvard Law School Environmental and Energy Law Program. The legislation is part of the broader American Energy Innovation Act, a collection of energy-related policies that has support from business and environmental groups. The bill is expected to be brought to the Senate floor in the coming weeks.