Home » Environment

The Kigali Amendment: Phasing Down Climate-Changing HFC Refrigerants

A global push to cut hydrofluorocarbons (HFCs) highlights climate action through innovation and policy, transforming cooling for a warmer world.

By Medha deb

Created on Sep 27, 2025

A global push to cut hydrofluorocarbons (HFCs) highlights climate action through innovation and policy, transforming cooling for a warmer world.

The Kigali Amendment: A Turning Point in Global Climate Action

The Kigali Amendment to the Montreal Protocol stands as one of the most significant climate mitigation initiatives of the 21st century. Designed to curb the use of hydrofluorocarbons (HFCs)—powerful greenhouse gases widely used in refrigeration, air conditioning, and insulation—the treaty marks an evolution from ozone preservation to broader climate stewardship. The ambitious framework aims to phase down HFCs globally and is set to avoid a projected 0.3 to 0.5°C rise in global temperatures this century, positioning itself as a cornerstone in international climate strategy.

Why Target HFCs? The Problem with Super-Pollutant Refrigerants

HFCs were originally introduced as a safer substitute for ozone-depleting chlorofluorocarbons (CFCs) after the 1987 Montreal Protocol. While HFCs do not degrade the ozone layer, scientists soon discovered that they possess an extremely high global warming potential (GWP)—ranging from hundreds to thousands of times more climate-forcing than carbon dioxide over the same period. As a result, what began as a solution to one environmental crisis quickly evolved into a new threat for the planet’s climate system.

HFCs are used in refrigerators, air conditioners, heat pumps, and insulation foam.
They are often released during the manufacture, servicing, and disposal of cooling equipment.
Many HFCs can persist in the atmosphere for years, intensifying their climate impact.

Without intervention, the projected growth in HFC use—driven by rising global demand for cooling—threatened to undermine achievements in climate mitigation. The Kigali Amendment was hammered out in 2016 to counter this trend through a legally binding, internationally coordinated action.

How the Kigali Amendment Works

The Kigali Amendment is an addendum to the Montreal Protocol, adopted by parties in 2016 and entering into force in January 2019. It commits countries worldwide to a phasedown (not an immediate phaseout) of HFC production and consumption over the next several decades.

Developed Countries: Began HFC reductions in 2019, targeting up to 85% cut in usage by 2036.
Developing Countries: Begin their reductions later, with most slated to reach an 80-85% cut by 2045 or 2047.

By linking national obligations to the total climate impact (or GWP) of HFCs used, countries are incentivized to adopt alternatives with much lower or zero global warming potential—such as hydrocarbons like propane, ammonia, or advanced synthetic blends.

Key Timeline for the HFC Phasedown

Group	Start Date	Reduction Milestone	End Date
Developed Countries	2019	85% reduction	by 2036
Most Developing Countries	2024	80-85% reduction	by 2045/2047

The U.S. Response: AIM Act and EPA Rulemaking

The United States has played a leading role in pushing the Kigali Amendment forward, both internationally and domestically. The American Innovation and Manufacturing (AIM) Act of 2020 enshrined the phasedown of HFCs into federal law, giving the Environmental Protection Agency (EPA) authority over HFC management, production, and consumption.

Major milestones in U.S. action include:

December 2020: AIM Act becomes law, mandating an 85% reduction of HFCs by 2036 to match Kigali targets.
September 21, 2022: U.S. Senate ratifies the Kigali Amendment.
October 2022: U.S. President signs the ratification, formalizing international support.

The EPA has since implemented several key rules:

Regulations on which refrigerants can be used in new products (SNAP Program/Rule 23).
Restrictions on manufacturing and importing HFC-based equipment after certain dates.
Guidance aligning building codes with low-GWP refrigerant safety standards.

Flexibility is built into the transition; for example, new residential and commercial A/C units using HFCs can be installed up to one year after manufacturing stops. Variable Refrigerant Flow (VRF) systems using high-GWP HFCs have received an installation deadline extension to allow a smoother market transformation.

Global Implementation: Different Approaches, Shared Goals

The Kigali framework divides signatory countries into different groups according to economic status, consumption patterns, and climate needs:

Group 1: Most developed countries (e.g., EU, U.S., Canada) take the lead and move fastest.
Group 2: Most developing countries, including China and Brazil, follow with a delayed but ambitious timeline.
Special provisions apply for some of the world’s hottest and poorest nations, recognizing their greater need for cooling under climate change and allowing a more gradual phase-down.

This structure ensures technical and financial support for developing countries, with assistance for technology transfer and training in safe handling of new, low-GWP alternatives.

Technological Innovation: What Happens Next for Cooling?

The global HFC phasedown is a catalyst for technological change across an enormous swath of industrial and consumer sectors. The shift is driving innovation in both well-established and emerging refrigerant chemistries.

Promising Alternatives to HFCs

Natural Refrigerants: Hydrocarbons (like propane (R-290)), ammonia (NH₃), and carbon dioxide (CO₂) exhibit extremely low or zero GWP and are gaining traction in commercial and industrial applications.
Low-GWP Synthetics: Blends like R-32 offer higher efficiency and reduced climate impact, although each carries its own trade-offs, including flammability or toxicity.
Advanced Systems: Innovations in heat pumps, secondary loop cooling, and magnetic or solid-state refrigeration are emerging as long-term, ultra-low-impact solutions.

Policy and market support for research and deployment is essential, particularly to meet the dual requirements of efficiency and safety. Many alternatives, such as hydrocarbons, are mildly flammable and require updated codes and robust training for safe use in appliances and buildings.

Social and Economic Impacts of the Transition

The transition away from HFCs brings both opportunities and challenges. Key factors include:

Industry Transformation: Manufacturers must re-tool plants, adapt supply chains, and train technicians for new refrigerant classes. Early investment pays off by opening access to global markets demanding compliant equipment.
Consumer Choices: New air conditioning and refrigeration units will need to meet performance and safety standards with lower-GWP refrigerants. These new systems are often more efficient, helping to reduce long-term energy costs.
Climate Benefits: Achieving the Kigali targets is projected to prevent hundreds of millions of tons of CO₂-equivalent emissions, directly supporting global climate stabilization goals.
Equity: Special financing and technology-sharing arrangements aim to ensure developing nations are not unduly burdened by the shift, while still benefiting from cleaner cooling.

Challenges and Criticisms

While the phasedown is broadly celebrated, several challenges and ongoing debates persist:

Safety and Regulations: New refrigerants may be more flammable or chemically sensitive than HFCs, posing regulatory, training, and safety implementation strains.
Retrofit Limitations: Most existing systems cannot be easily converted to use low-GWP alternatives, implying an extended lifespan for old HFC stock and potential emissions until their eventual replacement.
Economic Resistance: Some stakeholders in the refrigerant and cooling supply chain may resist early action or face short-term costs, necessitating transition aid and education.
Policy Coordination: Synchronizing international treaties, national regulations, and local building/safety codes is complex and requires constant adjustment and stakeholder engagement.

Looking Ahead: Kigali as a Model for Climate Agreements

Experts see the Kigali Amendment as a rare example of rapid, cooperative action with both environmental and economic upside. Its design leverages market incentives, international cooperation, and scientific evidence, yielding benefits well beyond the direct target of refrigerant gases.

Temperature Impact: Successful implementation is estimated to avert up to 0.5°C of warming by 2100.
Ozone and Energy: By encouraging more efficient cooling technology, the HFC phase-down also decreases energy use, complementing the original ozone protection aims of the Montreal Protocol.
Template for the Future: The Kigali process demonstrates how global treaties can address potent, fast-acting pollutants even as longer-term decarbonization (fossil fuel reduction) continues.

Frequently Asked Questions (FAQs)

What is the Kigali Amendment?

The Kigali Amendment is a 2016 agreement under the Montreal Protocol that requires countries to gradually phase down the use of climate-warming hydrofluorocarbon (HFC) refrigerants.

Why were HFCs used in the first place?

HFCs were developed as replacements for ozone-depleting substances like CFCs, but later found to be powerful greenhouse gases themselves.

How will the world replace HFCs?

Alternatives include natural refrigerants such as propane, ammonia, and CO₂, as well as new synthetic blends with much lower global warming potential. Each alternative has unique pros, cons, and safety considerations.

Will the phase-down of HFCs affect my air conditioner?

Older units using HFCs will continue to be serviceable for years, but new units will be required to use lower-GWP refrigerants over time, improving efficiency and reducing climate impact.

What can I do to support the Kigali goals?

Purchase climate-friendly appliances certified for low-GWP refrigerants, ensure proper servicing to prevent leaks, and support policies promoting sustainable cooling and energy use.

References

International – Fluorinated Greenhouse Gases, EU Climate Action
Explaining the Phasedown of HFC Refrigerants, Coward Environmental
Hydrofluorocarbons and the Kigali Amendment to the Montreal Protocol, Harvard EELP
2022 Scientific Assessment of Ozone Depletion, NOAA

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

Read full bio of medha deb