Why companies are phasing out these super-pollutants despite Trump

There’s one big bright spot in the fight against climate change that most people never think about.

It could prevent nearly half a degree of global warming this century, a huge margin for a planet that has warmed almost 1.5 degrees Celsius and is struggling to keep that number below 2 degrees. In a moment when companies are walking back their climate pledges and the United States has quit almost every climate organization or treaty you could name, more than 170 countries — including the U.S. — have agreed to act on this one solution.

That solution: phasing out hydrofluorocarbons (HFCs), a group of gases used in refrigerators, air conditioners and other cooling systems that heat the atmosphere more than almost any other pollutant on Earth. Pound for pound, HFCs are hundreds or even thousands of times better at trapping heat than carbon dioxide.

Companies are replacing HFCs with new gases that trap much less heat. If you buy a new fridge or AC unit in the United States today, it’ll probably use one of these new refrigerants — and you’re unlikely to notice the difference, according to Francis Dietz, a spokesperson for the Air-Conditioning, Heating and Refrigeration Institute, a trade group representing U.S. HVAC manufacturers.

“If we do our jobs, consumers don’t feel anything at all,” Dietz said.

But that invisible transition is one of the most important short-term tactics to keep Earth’s climate from going catastrophically off-kilter this century. HFCs are powerful super-pollutants, but the most common ones break down in the atmosphere within about 15 years. That means stopping emissions from HFCs — and other short-lived super-pollutants such as methane — is like pulling an emergency brake on climate change.

“It’s really the fastest, easiest and, some would say, the only way to slow the rate of warming between now and 2050,” said Kiff Gallagher, executive director of the Global Heat Reduction Initiative, a business that advises companies and cities on cutting greenhouse gas emissions. The only other solution that comes close to the speed and scale of slashing HFCs would be dimming the sun, a much more controversial and potentially dangerous option.

To be sure, the world still needs clean energy, electric vehicles and many other solutions to tackle carbon-dioxide emissions, which linger for centuries and are the biggest long-term problem for global warming.

But phasing out HFCs now “would buy us a little bit of time to develop other solutions that maybe take longer to implement,” said Sarah Gleeson, a climate solutions research manager at Project Drawdown, a nonprofit that models how much different strategies would slow climate change.

It could also keep the planet from crossing dangerous climate tipping points this century. With enough warming in the next few decades, scientists say tropical coral reefs could enter a death spiral, glaciers could collapse, and swaths of the Amazon rainforest could turn into arid savannas. To steer clear of these irreversible disasters, people need to slow down the rate of warming quickly.

Swapping out refrigerant gases is one of the easiest ways to do that because HFCs are used in only a few industries, and engineers have already found alternatives — although these come with trade-offs.

In the United States, new residential air conditioners typically use hydrofluoroolefins, which are similar to HFCs but trap less heat. But European regulators are already phasing these out for some products because they break down into “forever chemicals” that are building up in waterways.

Other alternatives include ammonia, propane or isobutane. These gases are toxic or flammable, so manufacturers build in safety mechanisms that can make these systems more expensive. Supermarket chains including Aldi, Trader Joe’s, Kroger and Walmart have pledged to build new stores with carbon-dioxide-based cooling systems. CO2 sidesteps the safety issues, but it works best under very high pressure, so it’s more practical in big, commercial systems than home appliances.

The cooling industry has been through this before: In the 1980s, world governments signed the Montreal Protocol to phase out chlorofluorocarbons (CFCs), the dominant refrigerant at the time, because scientists warned the gases were putting a hole in the ozone layer. It was one of the most successful global environmental treaties ever: Today, CFCs have mostly vanished, and the ozone hole is healing.

But the replacement gases, HFCs, are now overheating the planet. So, over the past decade, governments signed the Kigali Amendment to the Montreal Protocol and vowed to swap out HFCs. The United States officially ratified the treaty in 2022, and the Environmental Protection Agency required manufacturers to start phasing out HFCs in 2025.

As part of President Donald Trump’s broader effort to slash environmental regulations, the EPA proposed weakening HFC regulations last year, raising the limits on how much companies can pollute and pushing back the deadline for compliance. American manufacturers aren’t happy about the proposal, Dietz said.

“We changed all our equipment lines, we innovated the new equipment, and everything is rolling off the lines now,” Dietz said. “If you were to go back and allow the manufacture of equipment using the old refrigerants, that would just open up routes for foreign manufacturers to make further inroads into the United States market.”

Dietz said U.S. manufacturers aren’t turning back, even if the regulations get delayed. As people and businesses gradually replace their old, worn-out refrigerators, air conditioners and chillers, they’ll buy new equipment that doesn’t rely on HFCs. By around 2040, he said, most homes in the United States and other developed countries will probably have appliances that use the new refrigerants.

The transition will take longer in developing countries, according to Mark Shiflett, a chemical engineering professor at the University of Kansas who directs the Environmentally Applied Refrigerant Technology Hub. But, he said, it took the world about 30 years to kick ozone-depleting CFCs after the Montreal Protocol was signed, so it’ll probably take about that long to phase out HFCs globally, too.

“We solved an environmental crisis back in the ’90s” with the Montreal Protocol, Shiflett said. “Now we’re doing it again.”