A lot of climate change-fighting strategies focus on removing air pollutants, or preventing them from reaching the atmosphere at all. While pretty much everybody these days can recognize carbon dioxide and methane as two of them, the US just joined around 130 other nations to take a big step in knocking out a third: hydrofluorocarbons, also known as HFCs.
Some experts are marking the move “the most significant environmental treaty that the United States has joined in at least a decade.” Senate majority leader Chuck Schumer called it, alongside passage of the Inflation Reduction Act, as the “strongest one-two punch against climate change any Congress has ever taken.” But the push to get rid of the extremely potent group of greenhouse gases has a history decades in the making.
Thinning (and fixing) the ozone layer
HFCs first came onto the scene in the 1980s and 1990s to replace chlorofluorocarbons, or CFCs, in refrigerators and air conditioners. Those earlier substances were invented in the 1920s to make cooling and foaming agents. They had uniquely non-flammable, tasteless, and odorless properties, as well as a low boiling point close to zero degrees Celsius.
But CFCs were also a nightmare for the environment. The synthetic, which was also found in aerosolized products like hair spray, depleted the ozone layer by releasing chlorine into the atmosphere. Not to mention, the compounds produce a super-powered greenhouse gas that can warm the planet up to 10,000 times as much as carbon dioxide (though it doesn’t persist as long in the air).
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By 1974, researchers has figured out how bad CFCs—but the action didn’t really kick in until the signing of the Montreal Protocol in 1987. This agreement phased out the super powerful ozone killer and climate warmer, with goals for developed and developing countries to fully phase them out by 2020 and 2030, respectively.
But just as society will have to replace fossil fuels with renewable energy, something has to come in to substitute for CFCs. Enter HFCs, a slightly less toxic, ozone-safe option. Or so it seemed.
HFCs turn out to be a powerful greenhouse gas
The difference between HFCs and their predecessors was the fact that they lacked chlorine, the main ingredient in ozone depletion. But the newer chemicals came with their own environmental baggage. As far back as the 1990s, atmospheric scientists were also aware of the global warming impact that the compounds could have. “The US Environmental Protection Agency is concerned that rapid expansion of the use of some HFCs could contribute to global warming,” National Research Council (US) Subcommittee to Review Toxicity of Alternatives to Chlorofluorocarbons wrote in a report in 1996. “Nonetheless, use of HFCs offers lower overall risk than use of CFCs, as well as a reduction in the time needed to eliminate CFC use.”
Nevertheless, HFC use grew. The ones that replaced CFCs now represent about 1 percent of total greenhouse gas warming, and can potentially warm the planet hundreds of thousands times more than than carbon dioxide, based on mass, according to the Climate and Clean Air Coalition. According to the UN, HFC emissions are growing at a rate of around 8 percent every year, and annual emissions are projected to rise to 7 to 19 percent of global CO2 emissions equivalent by 2050.
Since 1990, the Montreal parties have phased out 98 percent of ozone-depleting substances, allowing the Earth’s protective layer to recover.
Since 2009, however, members of the Montreal Protocol have been negotiating the phaseout of these global warming menaces, resulting in the 2016 signing of the Kigali Amendment. Countries from the Montreal Protocol, including big players like India, the European Union, and China, agreed to add HFCs to controlled substance lists and approve timelines to knock down usage 80 to 85 percent by 2040. Developed nations started their reductions in 2019, with developing nations to follow a few years behind.
But notably, not the US. Donald Trump refused to sign it in 2016, even though it had bipartisan support and the backing of industry groups. Research from the Alliance for Responsible Atmospheric Policy and the Air-Conditioning, Heating, and Refrigeration Institute even found that signing it would increase exports of goods with HFC alternatives by $5 billion by 2027—and net thousands of US manufacturing jobs.
Another major step for US climate policy
Thankfully, a lot has changed in the past two years with climate policy. On September 21, 2022, the Senate quietly voted 69-27 to finally ratify Kigali and bring the US back on board with the the modern version of the Montreal Protocol. US Special Presidential Envoy for Climate John Kerry called it “a profound victory for the climate and the American economy.”
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If the Kigali Amendment follows in the footsteps of its CFC-focused predecessor, the impact could be major. Since 1990, the Montreal parties have phased out 98 percent of ozone-depleting substances, allowing the Earth’s protective layer to recover. (It’s estimated to be fully sealed up again by the 2050 or 2060s.) In the US alone, that means preventing 443 million cases of skin cancer, 2.3 million skin cancer deaths, and 63 million cases of cataracts by 2100.
Assuming the US government fully follows through on Kigali, it could be the single largest contribution by people to keeping the planet below two degrees Celsius of warming—the threshold associated with keeping the planet livable for humans and other species. Wiping out HFC use under this agreement can help prevent more than 100 million tons of carbon dioxide emissions, which means avoiding up to 0.5 degree Celsius of global temperature rise by 2100.
Of course, there is still much to be done on climate change policy at home and abroad—but the ratification is a massive victory to climate-minded policymakers and activists. “This action will encourage other countries to join the agreement,” Dan Lashof, the US director of the World Resources Institute said in a release. “[It will] send a strong signal to the rest of the world that the nation is serious about addressing the climate crisis and investing in a cleaner, more sustainable economy.”