Kigali Era Gateway to Climate Friendly Cooling Under the Montreal Protocol

This paper presents the latest successes of the Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol), driven by the 2016 Kigali Hydrofluorocarbon (HFC) Phase Down Amendment and the complementary 2016 Kigali Energy Efficiency Decision XXVIII/3.[1] The information in this paper is based on our forthcoming book: Protecting the Ozone Layer & Climate: Kigali Energy Efficiency Triumph [2], published in partnership with the Climate and Clean Air Coalition (CCAC), the Montreal Protocol Ozone Secretariat, and the Institute for Governance & Sustainable Development. This essay highlights the importance of leadership by corporations, governments, and citizens in avoiding climate tipping points while minimizing the accumulation of trifluoroacetic acid (TFA) from HFC and hydrofluoroolefin (HFO) refrigerants, and by avoiding the formation of hazardous volatile organic compounds (VOCs) from hydrocarbon refrigerants. It presents a blueprint for the way forward on unfinished business, including lifecycle refrigerant management (LRM), access to the best available technology, and manufacturers’ graceful withdrawal from hazardous fluorocarbons as soon as they are no longer needed.

Kigali Era (2009-2026) Successes of the Montreal Protocol

We define the “Kigali Era” as the period between the 2009 science warning by Velders et al. and the 2026 10th Anniversary of the Kigali Amendment and Kigali Decision that has repurposed the Montreal Protocol ozone treaty to ambitiously protect climate.

The metric for climate friendly cooling is life cycle climate performance (LCCP) taking into account direct refrigerant greenhouse gas (GHG) emissions, indirect carbon-equivalent energy emissions, and embodied GHG emissions from equipment manufacture, marketing, servicing and recycle at end of product lifetime (Hwang et al. 2016; Andersen et al. 2018). Added to that are the non-climate concerns of atmospheric fate, safety, and toxicity.

• The ozone layer is the only Planetary Boundary breached and then recovered from the danger zone, offering hope for a sustainable Earth!
• 2026 is the last Replenishment of the Multilateral Fund for the Implementation of the Montreal Protocol (MLF) for ozone-depleting substance (ODS) phaseout—the next Replenishment will be for HFC phasedown and energy efficiency!
• MLF Executive Committee Decisions opened US $20 million, US $40 million, and US $100 million energy-efficiency funding windows!
• The Africa Group campaign calling for access to best available cooling technology and importer-exporter cooperation to stop the dumping of inefficient cooling equipment is reflected in Montreal Protocol Decision (XXXV/13) and the Preamble to the EU F-gas Regulation 2024/573)! This campaign is inspiring other countries to demand access to energy efficiency appliances without obsolete ODS and HFC refrigerants.
• Manufacturers of energy-efficient room air conditioners (RACs) are penetrating global markets. For example, in Ghana, efficient inverter R-32 and R-290 models are increasingly offered; both refrigerants have no atmospheric degradation to TFA! Brands that now offer R-290 models in Ghana are Hisense, Midea, and GREE. Brands that now offer R-32 models in Ghana include Amcon, Chigo, Gree, Haier, Hilbery, Hisense, Innova, MDV, Midea, SPS, TCL, and H&A.
• Leadership by Japan has advanced LRM in the Montreal Protocol, including as reflected in Japan’s co-chairmanship of the CCAC Cooling Hub and the recently published National Action Plans for Lifecycle Refrigerant Management: A Practical Guide for Developing Countries!
• The “Accra-Helsinki Group on Sustainable Cooling,” which evolved from the legacies of the Montreal Protocol “Toronto Group” and the “Stockholm Group,” is the new, informal incubator for ambitious ideas outside the formal plenary and contact group meetings, for fast action to strengthen the Montreal Protocol.
• Breakthrough cooling technology including rapidly expanding the safe use of natural hydrocarbon refrigerants in stand-alone refrigeration, room and portable air conditioners, and in secondary-loop heat pumps for all-electric vehicles.
• Breakthrough R-32 cooling technology achieving lowest carbon footprint in high ambient temperature by superior energy efficiency, larger safe refrigerant charge, and leak tight design and service.
• Greater energy efficiency driven by minimum national and voluntary energy performance standards enhanced by the rapid implementation of clean wind and solar energy and occupant spaces designed for reduced cooling and heating demands!
• Parties and national authorities are considering policy responses to newly published science in the journal Nature warning that feedstock emissions will delay mid-latitude ozone recovery by 7 (6-11) years (Reimann et al. 2026) and earlier published policy analysis in the Proceedings of the National Academy of Sciences (PNAS) providing options for narrowing the feedstock exemptions under the Montreal Protocol, while also documenting that ODS and HFC are used as plastic feedstocks, contaminating workplaces and communities and contributing downstream to the contamination of fresh water, land, oceans, and atmosphere, and providing options for upstream controls under the Montreal Protocol (Andersen et al. 2018).

The success of the Montreal Protocol in sustainable cooling is from the many industry and public interest organizations working together to transition away from inefficient cooling products with obsolete refrigerants, particularly in the developing world. They work to remove barriers and implement standards in support of environmentally superior HFC replacements, and promote professional installation and service, including LRM and local cement kiln destruction of surplus ODSs and HFCs consistent with Montreal Protocol decisions.

Table 1 below presents an indicative list of public-interest and industry non-governmental organizations (NGOs) that supported the adoption of the Kigali Amendment. Table 2 is a summary of seven eras of cooling since the industrial revolution beginning in about 1800.

Table 1

Indicative List of Non-Governmental Organizations

Supporting Adoption and Implementation of the Kigali Amendment[3]

Air Conditioning Contractors of America (ACCA)
Air-Conditioning, Heating, and Refrigeration Institute (AHRI)
Alliance for Responsible Atmospheric Policy (ARAP)
American Chemistry Council (ACC)
American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
Basel Agency for Sustainable Energy (BASE)
Brazilian Refrigeration, Air Conditioning and Ventilation Industry Association (ABRAVA)
Business Roundtable
Center for Climate and Energy Solutions (C2ES)
Center for Shared Responsibility and Technology Ambition (CSRTA)
Centro Studi Galileo (CSG) – Industria & Formazione
Climate Action Network (CAN) International

Climate and Clean Air Coalition (CCAC)
Council on Energy, Environment, and Water (CEEW)
Environmental Defense Fund (EDF)
Environmental Investigation Agency (EIA) (USA and UK)
European Partnership for Energy and the Environment (EPEE)
Greenpeace International
Industrial Technology Research Institute (ITRI)
Institute for Governance & Sustainable Development (IGSD)
Instituto Clima e Sociedade (ICS)
International Institute of Refrigeration (IIR)
Japan Electrical Manufacturers’ Association (JEMA)
Japan Refrigeration and Air Conditioning Industry Association (JRAIA)
Korea Refrigeration Air-Conditioning Industry Association (KRAIA)
Latin America and Caribbean Network for Sustainable Cooling (LAC Cool)
National Association of Manufacturers (NAM)
Natural Resources Defense Council (NRDC)
Sustainable Energy for All (SE for All)
Semiconductor Industry Association (SIA)
United States Chamber of Commerce (USCC)
World Resources Institute (WRI)

Table 2

The Seven Historic Eras of Cooling and the Likely Eighth Era[4]:

1) Primitive refrigeration (root cellars, spring houses, local winter ice used in hotter months, evaporating water, and handheld fans)
2) Point-of-use manufactured ice using toxic and flammable refrigerants;
3) Distributed mechanical refrigeration, still using toxic and flammable refrigerants;
4) Odourless, colourless, non-flammable, non-toxic, energy efficient, and affordable CFCs that are ozone-depleting greenhouse gases
5) Ozone-safe, flammable and toxic, low-GWP natural refrigerants (ammonia, CO₂, and hydrocarbons) plus ozone-safe, non-flammable, non-toxic HFC greenhouse gases (some degrading to hazardous TFA)
6) Expanded use of natural refrigerants plus non-flammable, non-toxic, low-GWP HFOs (most degrading to hazardous TFA)
7) Expanded use of natural refrigerants plus TFA-free HFCs and HFOs; all in leak-tight systems with LRM, including destruction at the end of useful life.
8) The next “Moonshot”[5] cooling era might be solid state cooling, including barocaloric, elastocaloric, magnetocaloric, and thermoelectric (no doubt with advanced building placement and orientation, design, insulation, landscaping, and water features, reflectivity, shading, thermosiphoning, etc.)

The Continuing Saga of Refrigerants with Unanticipated Consequences

Storage of perishable food was first accomplished by canning, drying, fermenting, pickling, salting, smoking, sterilization, sulfurating, and sugaring. Refrigeration and air conditioning began with natural technology such as shading, root cellars, spring houses, water evaporation, and hand-held fans. Cooling evolved in cold climates to use winter ice stored for summer use, and then to global trade in ice to markets without annual freezing temperatures. When natural ice sources were bilocally and chemically contaminated emerging motive power was used to make ice from clean local sources with flammable and toxic refrigerants such as ammonia (NH₃), carbon dioxide (CO₂), ethers, hydrocarbons, sulphur dioxide (SO₂), and methyl chloride (CH₃Cl). With the invention of electricity generation, companies abandoned ice as a transportable cold ballast and concentrated on point-of-use cooling equipment located in businesses and homes but still using flammable and toxic refrigerants (Andersen and Sarma 2002; Andersen, Halberstadt, and Borgford-Parnell 2013).

Before 1930, mechanized cooling equipment used flammable and toxic refrigerants that maimed and killed humans and destroyed property. In 1930, a joint venture of General Motors and DuPont began marketing chlorofluorocarbons (CFCs) that are non-flammable, non-toxic, colourless, odourless, energy efficient, and affordable.[6] Until 1974 it was not appreciated that CFCs deplete stratospheric ozone that shields Earth against harmful ultraviolet radiation[7] (Molina and Rowland 1974) and until 1975 it was not appreciated that CFCs are powerful greenhouse gases (GHGs) (Ramanathan 1975). Likewise, when HFCs first replaced CFCs, it was not appreciated that economic growth in Article 5 markets coupled with global inaction on carbon dioxide from fossil fuel would make high global warming potential (GWP) refrigerants unsustainable. And until the about 1990, it was not appreciated that many HFCs and HFOs atmospherically decompose to TFA. Similarly, it is not yet appreciated that hydrocarbon refrigerants are unsustainable unless responsibly supplied from non-fossil fuel sources or where otherwise emitted and should be in leak tight equipment serviced with recovery and reuse or destruction to mitigate VOC damage to health and ecosystems.

In 1985, British scientists warned of a seasonal Antarctic ozone hole the size of Texas and in 1987 the Montreal Protocol was agreed as a Start and Strengthen treaty that started with just a 50% reduction in a short list of CFCs and a freeze in halon and was strengthened to almost 100 ozone-depleting substances (ODSs) that are now 99+% phased out worldwide from production and consumption.

A Common-Sense Way Forward on TFA

TFA accumulation is an unanticipated consequence of saving the ozone layer by the rapid replacement of 15% of ODSs with HFCs and HFOs, while 85% was replaced with not-in-kind solutions. The Montreal Protocol dilemma is that without a rapid HFC phasedown or phaseout, carbon-equivalent climate forcing may exceed climate tipping points that could end life on Earth until recovery over geologic time. The technical reality is that not all HFCs and HFOs can be replaced in the immediate future.

One common-sense way forward to minimize and mitigate TFA and VOCs while avoiding climate tipping points is to:

• Restrict domestic sales and export the use of any HFC or HFO that degrades to TFA when energy efficient alternatives with superior life cycle climate performance (LCCP) are available that satisfy critical environmental, health, and safety criteria,
• MLF to incentivize A5 Parties leapfrogging TFA refrigerants, and to avoid refrigerants that degrade to TFA
• Collect and destroy ODS and HFC banks with TFA trading and offsets as financial bonus for destruction avoiding TFA (Dreyfus et al. 2024)
• Early replacement of installed cooling equipment that was inefficient when purchased and improperly installed and serviced for energy efficiency with financial bonus for destruction avoiding TFA
• Find synergy with accelerated transition to all-electric vehicles using R-290 SL-heat pumps

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[1] An Amendment under the Montreal Protocol adds new chemicals to the control schedule and requires ratification for entry into force. Adjustments and Decisions under the Montreal Protocol fine tune the pace and details of control measures and require consensus of Parties to the Montreal Protocol, not ratification.

[2] Readers wanting elaboration can download, via Amazon Kindle, after the November 2026 35th Meeting of Parties.

[3] Corporate and associated private and public organization support for agreement on the Kigali Amendment was driven by the overall advantage of a global framework based on science and economic and technical feasibility; professionalized design, installation, and service of increasingly complex machinery; national and global energy efficiency for ownership affordability and community prosperity; and clean air and climate co-benefits. Many companies preferring not to be regulated for reasons of environmental sustainability came to the realization that if regulation were inevitable it would be more competitive, profitable, and successful under the Montreal Protocol than elsewhere.

[4] Adapted and updated from Andersen, Halberstadt, and Borgford-Parnell 2013. Calm 2012, Harry, 1999; Donaldson and Nagengast, 1994; and Nagengast, 1988.

[5] “Moonshot” technology is highly ambitious, breakthrough inventions aimed at solving massive global problems by developing radical, futuristic solutions.

[6] CFC-11 was invented in 1928, CFC-12 in 1930, and HCFC-22 in 1934. Chemists continued to invent new fluorocarbons and companies aggressively marketed them ultimately into more than 240 sectors at prices resulting in high life cycle emissions.

[7] Stratospheric ozone shields Earth against ultraviolet radiation that increases skin cancer and cataracts, damages agricultural and natural ecosystems, diminishes aquatic and terrestrial carbon sinks, and deteriorates the built environment.