Montreal, Kyoto, Kigali: How the World Built a Refrigerant Control System (One Layer at a Time)

On a global scale, refrigerants are governed by three major international agreements.

Each one solved a different part of the problem:

• Montreal Protocol (1987) → fixed the ozone problem.

• Kyoto Protocol (1997) → formally recognized HFCs as greenhouse gases.

• Kigali Amendment (2016) → put HFCs on a global phasedown schedule.

Together, they form a layered control system for refrigerants. But they were built in stages — because the risks emerged in stages.

Let’s walk through what each one actually did.

1. Montreal Protocol (1987): Stop Ozone Destruction

Problem addressed: Ozone layer depletion

Chemicals targeted: CFCs, halons, carbon tetrachloride, methyl chloroform, later HCFCs

The Montreal Protocol was adopted in 1987 and entered into force in 1989. Its mission was clear: phase out chemicals that destroy the stratospheric ozone layer.

These were primarily chlorine-containing refrigerants like CFCs and later transitional replacements like HCFCs.

What Montreal did:

• Established production and consumption controls

• Created legally binding phaseout schedules

• Built a compliance and reporting system

• Established a Multilateral Fund to help developing countries transition

This is the treaty responsible for the ongoing recovery of the ozone layer. It is widely considered one of the most successful environmental agreements ever implemented.

But Montreal did not originally regulate HFCs—because HFCs don’t destroy ozone.

They were the solution at the time.

2. Kyoto Protocol (1997): Recognize the Climate Problem

Problem addressed: Climate change

Chemicals targeted (among others): HFCs

By the mid-1990s, the climate impacts of various industrial gases were well understood. In 1997, the Kyoto Protocol formally included HFCs in its “basket” of greenhouse gases.

This was significant for one reason: it officially recognized that HFCs were a climate issue.

What Kyoto did:

• Classified HFCs as greenhouse gases

• Required developed countries to track and reduce overall emissions

• Enabled carbon market mechanisms that included HFC-related projects

  
  

But Kyoto did not create a dedicated refrigerant control system. It treated HFCs as part of an economy-wide emissions accounting framework.

That meant:

• No global production caps specific to HFCs

• No structured refrigerant transition schedule

• No universal participation (some major countries were not bound)

  
  

Kyoto acknowledged the climate impact of HFCs. It did not structurally solve it.

3. Kigali Amendment (2016): Phase Down HFCs

Problem addressed: High-GWP refrigerants

Chemicals targeted: HFCs

In 2016, the Kigali Amendment added HFCs to the Montreal Protocol framework.

This was the critical shift: instead of handling HFCs under general climate accounting (Kyoto), they were brought into the highly effective Montreal machinery—production controls, reporting, compliance, and staged reductions.

Kigali entered into force in 2019.

What Kigali does:

• Establishes baselines for HFC production and consumption

• Sets stepwise phasedown schedules

• Uses differentiated timelines for developed and developing countries

• Operates under Montreal’s proven compliance architecture

  
  

This is expected to significantly reduce projected HFC growth over the century.

But Kigali is a phasedown, not an immediate ban. And it primarily targets new production and consumption, not the vast installed base already operating.

How They Work Together (Specifically for Refrigerants)

Here’s the simplest way to understand the system:

Agreement	Core Function for Refrigerants	What It Controls
Montreal (1987)	Eliminates ozone-depleting refrigerants	CFCs, HCFCs
Kyoto (1997)	Recognizes HFCs as greenhouse gases	Emissions accounting
Kigali (2016)	Phases down HFC production and consumption	HFC supply

Think of it like layers of defense:

1. Montreal stopped ozone damage.

2. Kyoto acknowledged climate damage.

3. Kigali built a refrigerant-specific climate control system.

Each step built on the last.

What None of Them Fully Solve

All three agreements primarily control production and consumption.

They do not automatically eliminate:

• Annual leakage from existing systems

• Emissions from poorly maintained infrastructure

• Long-lived refrigerant “banks” already in equipment

• Perverse incentives in poorly structured credit systems

And this is where the climate math gets real.

Cooling systems are long-lived infrastructure. They leak every year. And refrigerants are super pollutants—extremely potent, and once released, effectively irreversible.

Global agreements are necessary. But they don’t replace operational action.

The Big Picture

Montreal proved refrigerants can be governed successfully.

Kyoto recognized their climate potency.

Kigali applied Montreal’s machinery to HFCs.

Together, they represent 40 years of policy evolution.

But the remaining emissions problem isn’t theoretical production growth.

It’s what’s already installed. It’s what leaks every year. It’s what goes up—and can’t come back down.

That’s the chapter we’re in now.