Celebrating Montreal Protocol’s Climate Success

With summer of 2024 just declared the hottest on record , the prospects of effectively tackling climate change may seem sadly remote—a mountain too steep to climb.

But as we remember every World Ozone Day , we’ve climbed this mountain before. We?built a mandatory global agreement to phase?out the harmful propellants used in spray cans and as refrigerants in air conditioning that were destroying the stratospheric ozone layer—and, as a planet-saving bonus, avoided as much warming as carbon dioxide currently causes.

Since it was agreed in 1987, the #MontrealProtocol has phased out the production and consumption of?nearly?100 harmful chemicals?by nearly 100 percent ?with its mandatory controls, putting the ozone layer on the path to?recovery by 2066 ?and preventing?two million skin cancer deaths?a year .

Because those same chemicals that destroy ozone are also?climate super pollutants, it has also done more than any other policy to combat climate change. Indeed, the Montreal Protocol is on course to avoid 2.5o?Celsius ?by end of century.

The evolution of the Montreal Protocol into an explicit climate treaty started in 2007, when the Parties agreed to accelerate the phaseout of ozone-depleting refrigerants called hydrochlorofluorocarbons explicitly because they also caused warming. Then, in 2016, they agreed to phase down hydrofluorocarbon (HFC) refrigerants through the?Kigali Amendment . This will avoid?up to half a degree Celsius of future warming. ?If air conditioners are made more efficient while switching refrigerants – a strategy the?Protocol’s multilateral fund has?just agreed to support with $100 million for developing country Parties – the?climate benefits will be twice as much .

?The Parties are currently considering other way to strengthen the Protocol, including by preventing dumping ?of inefficient cooling equipment containing obsolete refrigerants, limiting exemption s?for feedstocks used to make other products, and perhaps phasing down ozone-depleting and climate-warming nitrous oxide emissions ?from industry.

?It all adds up to an extraordinary accomplishment that we need to celebrate. We also need to use the Protocol as a model for tackling other parts of the climate emergency, starting with the other short-lived climate super pollutants – methane, tropospheric (ground-level) ozone, and black carbon soot, along with the longer-lived nitrous oxide. Together with HFCs, these non-carbon dioxide climate pollutants are responsible for?nearly half of today’s warming ?yet have been largely neglected in the UN climate negotiations.

This failing is all the more discouraging because the climate super pollutants offer what may be the best opportunity to prevent climate change from escalating out of control as self-amplifying feedback loops push the planet past?irreversible tipping points that are just ahead . This is because – as well as being much more powerful, molecule for molecule, at warming the planet than carbon dioxide – short-lived pollutants fall out of the atmosphere much faster, in weeks to a decade and a half as opposed to centuries for carbon dioxide.

?When combined with decarbonization, cutting the super pollutants can avoid four times more warming by 2050 ?than reducing carbon dioxide alone. HFCs are already being phased down under the mandatory Kigali Amendment. The next target is methane, where fast mitigation could save nearly 0.3° Celsius ?of warming by the 2040s. The 158 countries in the ?Global Methane Pledge got the ball rolling, and recently launched methane-hunting satellites ?are adding momentum.

The European Parliament previously called on the Commission and Member States to “negotiate a binding global agreement on methane mitigation .” ?The oil and gas sector is overdue for such action. Responsible for about a third of methane emissions, many companies have already pledged to cut emissions to near zero by 2030.? The biggest buyers of natural gas, which is 90 percent methane, could converge around a common standard and use border adjustment mechanisms to ensure that sellers keep their promises to produce gas with the lowest emission profile.

This could be followed by agreements to mandate methane mitigation from waste, and then—with a light touch—from agriculture, the other two main sources. Many of the mitigation measures are cheap: about half of those required for oil and gas would actually save money.

?While it won’t be easy, a methane agreement that moves from pledges and promises to mandatory measures would be worth the effort. In the meantime, we need to keep strengthening the Montreal Protocol as we celebrate its planet-saving success.

Coauthored with Maxime Beaugrand Margetson , IGSD Director of the Paris Office.