Kigali Amendment to the Montreal Protocol — The Definitive Reference

Executive Summary

The Kigali Amendment is the binding multilateral treaty instrument that brings hydrofluorocarbons (HFCs) under the same Montreal Protocol architecture that has driven the global phase-out of chlorofluorocarbons (CFCs), halons, hydrochlorofluorocarbons (HCFCs), and other ozone-depleting substances since 1987. The amendment was adopted by consensus at the 28th Meeting of the Parties to the Montreal Protocol (MOP28), convened in Kigali, Rwanda from 10 to 14 October 2016, with the formal adoption on 15 October. The amendment text was deposited with the United Nations Secretary-General as depositary on 17 October 2016. It entered into force globally on 1 January 2019, having reached the 20-Party ratification threshold required by its Article IV.

The amendment does five things uniquely. It adds 18 HFCs as a new class of controlled substances to the Montreal Protocol via a new Annex F (Group I: 17 HFCs and HFC blends; Group II: HFC-23 separately). It establishes three differentiated phase-down schedules — one for Non-Article 5 (developed) Parties reaching 15% of baseline by 2036, one for Article 5 Group 1 (most developing) Parties reaching 20% of baseline by 2045, and one for Article 5 Group 2 (high-ambient-temperature) Parties reaching 20% of baseline by 2047. It denominates all consumption and production limits in CO₂-equivalent terms, using GWP-100 values listed in Annex F (drawn from IPCC AR4), distinguishing the Kigali architecture sharply from the original Montreal Protocol’s ozone-depletion-potential (ODP) basis. It establishes a trade-restriction regime under Article 4B that bans HFC imports from and exports to non-Parties from 1 January 2033, replicating the trade-discipline mechanism that drove near-universal ratification of the underlying Protocol. It commits the Multilateral Fund to financing the Article 5 transition, with replenishments specifically including incremental costs for HFC phase-down implementation.

What the Kigali Amendment Is — and Is Not

The Kigali Amendment is a treaty amendment under Article 9 of the Vienna Convention for the Protection of the Ozone Layer (1985), formally amending the Montreal Protocol on Substances that Deplete the Ozone Layer. It is the fifth amendment to the Protocol — following the London Amendment (1990), Copenhagen Amendment (1992), Montreal Amendment (1997), and Beijing Amendment (1999) — and is the first amendment to bring under control a class of substances that are not themselves ozone-depleting. It does so on the substantive policy ground that the controlled substances are climate forcers of an order of magnitude warranting their inclusion in the Protocol’s well-tested mechanism of phase-down, trade discipline, and Multilateral Fund financing.

The amendment is not the Montreal Protocol itself, not the Paris Agreement, not an EU instrument, not a U.S. domestic law, and not a corporate-disclosure framework. It is a public international-law instrument that creates binding obligations on the States Parties to it; it does not, by itself, create direct legal obligations on private operators — those obligations arise only when ratifying Parties enact domestic implementing legislation. The EU F-Gas Regulation, the U.S. AIM Act, the UK retained F-Gas regime, China’s HFC controls, and India’s phase-down schedule are the domestic instruments through which the Kigali obligations bind producers, importers, and operators within each Party’s jurisdiction. See EU F-Gas Regulation 2024 for the EU implementing law in detail.

“HFCs” under the amendment means the 18 substances listed in the new Annex F — principally HFC-134a, HFC-32, HFC-125, HFC-143a, HFC-152a, HFC-227ea, HFC-245fa, HFC-23, and other HFC isomers — together with mixtures (refrigerant blends) containing those substances. The amendment does not control hydrofluoroolefins (HFOs), perfluorocarbons (PFCs), sulphur hexafluoride (SF₆), nitrogen trifluoride (NF₃), or natural refrigerants (CO₂, ammonia, hydrocarbons), even though many of these substances are otherwise subject to climate regulation. The Kigali architecture is therefore tighter than the F-Gas Regulation’s broader Annex I scope: every Kigali substance is a Regulation 2024/573 Annex I substance, but the reverse is not true.

Why the Kigali Amendment Exists

The Kigali Amendment exists because of a structural feedback in the original Montreal Protocol. The 1987 Protocol and its first four amendments drove the global phase-out of CFCs (Annex A Group I), halons (Annex A Group II), other fully-halogenated CFCs (Annex B Group I), carbon tetrachloride (Annex B Group II), methyl chloroform (Annex B Group III), HCFCs (Annex C Group I), HBFCs (Annex C Group II), bromochloromethane (Annex C Group III), and methyl bromide (Annex E). The phase-out was an environmental success of historic proportions — the stratospheric ozone layer is now in measurable recovery, with the Antarctic ozone hole projected to return to 1980 values around 2066 — but the technical transition was largely accomplished by substituting HFCs for the ozone-depleting predecessors. HFCs have zero ozone-depletion potential, which made them the natural near-term replacement in refrigeration, air-conditioning, foams, aerosols, and fire-protection applications. They also have very high global warming potentials — HFC-134a at 1,430 (AR4) / 1,300 (AR5) / 1,530 (AR6); HFC-125 at 3,500 / 3,170 / 3,740; HFC-143a at 4,470 / 4,800 / 5,810; HFC-23 at 14,800 / 12,400 / 14,600 — making their atmospheric accumulation a substantial and growing contribution to climate forcing.

Without targeted regulation, global HFC consumption was projected to grow rapidly through the 2020s and 2030s as the Article 5 (developing-country) HCFC phase-out under the Montreal Protocol’s 2007 Adjustment continued to transition air-conditioning, refrigeration, and foam-blowing applications onto HFC substitutes. UNEP and modelling teams calculated that, on an unmitigated trajectory, HFC consumption could rise to the equivalent of 9–19% of CO₂ emissions by 2050 in CO₂e terms, with the largest growth driver being the expansion of residential and commercial air-conditioning in high-ambient-temperature regions where cooling demand is rising fastest with both economic development and climate warming.

The Kigali Amendment is the policy response. It uses the same instrument architecture — controlled-substance annex, phase-down schedule, trade discipline with non-Parties, Multilateral Fund financing for Article 5 implementation, MOP-level governance — that has driven the underlying Protocol’s near-universal compliance, redirected to the HFC class. The drafting choice to embed HFC controls in the Montreal Protocol rather than in the UNFCCC was both pragmatic (the Montreal Protocol’s compliance track record is stronger) and substantive (the HFC transition is driven by the same equipment fleets, supply chains, and technical alternatives that the Protocol already addresses through its HCFC phase-out work).

The Path to Kigali — 1987 to 2016

The Kigali Amendment did not arrive in a vacuum. It is the culmination of a thirty-year arc that began with the discovery of the Antarctic ozone hole in 1985 and the immediate diplomatic response that produced the Vienna Convention and Montreal Protocol. Key milestones below are reconciled to the depositary records held by the United Nations Treaty Section and the Ozone Secretariat.

Governance — UNEP, MOP, and the Implementation Committee

The Kigali Amendment is governed by the same institutional architecture as the underlying Montreal Protocol. Five bodies share the governance load.

The Meeting of the Parties (MOP) is the supreme decision-making body. It convenes annually and is the forum in which adjustments to phase-down schedules, additions to controlled-substance annexes, exemptions for essential and critical uses, financial decisions on the Multilateral Fund, and procedural matters are decided. Adjustments to the phase-down schedules of already-listed substances can be made by a supermajority decision (two-thirds of Parties, including independent majorities of Article 5 and Non-Article 5 Parties). Amendments adding new substances or substantive new obligations require formal ratification by individual Parties.

The UNEP Ozone Secretariat, headquartered in Nairobi, is the operational secretariat. It administers the annual reporting cycle under Article 7 of the Protocol (data due by 30 September each year for the preceding calendar year), maintains the depositary functions for ratification status, services the MOP and the Open-ended Working Group, and publishes the consolidated Handbook for the Montreal Protocol that aggregates the Protocol text with all adopted amendments, adjustments, and MOP decisions.

The Implementation Committee under the Non-Compliance Procedure reviews Parties that may be in non-compliance with their Protocol obligations. The Committee’s remit covers consumption and production reporting, licensing-system implementation, data accuracy, and the procedural obligations under Article 7. The Committee operates by facilitation rather than sanction: where a Party is found to be in non-compliance, the typical response is an action plan agreed with the Party and supported by Multilateral Fund resources where applicable.

The Scientific Assessment Panel, the Environmental Effects Assessment Panel, and the Technology and Economic Assessment Panel (TEAP) are the three permanent assessment bodies. They produce quadrennial scientific assessments (the next is due in 2026) and ad hoc reports on technical questions referred to them by the MOP. The TEAP’s Refrigeration, Air-Conditioning and Heat Pumps Technical Options Committee (RTOC) is the principal technical reference point for assessment of low-GWP refrigerant alternatives.

The Multilateral Fund (MLF), established by the London Amendment in 1990 and operational since 1991, finances the incremental cost of compliance for Article 5 Parties. The MLF Secretariat in Montreal administers project approvals through quarterly Executive Committee meetings. The fund is replenished triennially by Non-Article 5 contributing Parties; the most recent replenishment specifically incorporates resources for HFC phase-down implementation in Article 5 countries.

The Three Country Groups

The Kigali Amendment’s defining design feature is the three-group differentiation. The underlying Montreal Protocol already distinguishes “Article 5 Parties” (developing countries operating under the lower-income provisions of Protocol Article 5) from “Non-Article 5 Parties” (developed countries operating under the standard provisions). The Kigali Amendment subdivides the Article 5 group into two sub-groups reflecting the structurally different cooling-demand profile of high-ambient-temperature countries.

Non-Article 5 Parties (the “developed-country group”)

The Non-Article 5 group covers the high-income economies that joined the Montreal Protocol under the standard provisions. This includes the European Union member states, the United States, Canada, Japan, Australia, New Zealand, Norway, Switzerland, the United Kingdom, and the other OECD-equivalent economies. These Parties have the most ambitious schedule: baseline frozen at 2019; staged reductions to 60% in 2024, 30% in 2029, 20% in 2034, and 15% in 2036; held at 15% of baseline thereafter.

Article 5 Group 1 (most developing countries)

Article 5 Group 1 covers the majority of developing-country Parties. Key Parties in Group 1 include China, Brazil, Indonesia, South Africa, Mexico, the Philippines, Vietnam, Thailand, most of Sub-Saharan Africa, and most of Latin America and Southeast Asia. These Parties freeze HFC consumption and production at baseline on 1 January 2024 (or, if later, on the date when their consumption first reaches the baseline level), with the formal freeze step in 2029 followed by staged reductions to 90% in 2029, 70% in 2035, 50% in 2040, and 20% in 2045.

Article 5 Group 2 (high-ambient-temperature developing countries)

Article 5 Group 2 covers the high-ambient-temperature countries that successfully argued at MOP28 for a longer phase-down period reflecting their higher cooling demand and the slower availability of low-GWP refrigerants suitable for high-ambient operating conditions. The Group 2 Parties are: Bahrain, India, Iran, Iraq, Kuwait, Oman, Pakistan, Qatar, Saudi Arabia, and the United Arab Emirates. These Parties freeze on 1 January 2028, with staged reductions to 90% in 2032, 70% in 2037, 50% in 2042, and 20% in 2047.

The Group 2 designation is fixed in the amendment text and is not available to new applicants — the list of countries was negotiated at MOP28 and is closed. Group 1 Parties cannot transfer to Group 2.

The HFC Baseline Calculation

Each country group has a distinct baseline definition — the reference quantity against which all subsequent percentage reductions are measured. The baseline is denominated in tonnes CO₂e, calculated using GWP-100 values listed in Annex F of the amendment (drawn from IPCC AR4).

Non-Article 5 baseline

The Non-Article 5 baseline is the average of the Party’s annual HFC consumption (or production) over the reference years 2011, 2012, and 2013, plus an adjustment of 15% of the Party’s HCFC baseline (the HCFC baseline being the value already established under the Protocol’s HCFC controls). The HCFC component of the baseline reflects the technical reality that HFCs are substituting for HCFCs in many applications, and so a portion of a country’s permitted HCFC consumption is effectively translated into permitted HFC consumption at baseline.

Article 5 Group 1 baseline

The Article 5 Group 1 baseline is the average of annual HFC consumption (or production) over the reference years 2020, 2021, and 2022, plus 65% of the HCFC baseline. The higher HCFC-component percentage (65% vs 15% for Non-Article 5) reflects the larger HCFC consumption share that Group 1 Parties were transitioning out of at the time of the amendment’s adoption.

Article 5 Group 2 baseline

The Article 5 Group 2 baseline is the average of annual HFC consumption (or production) over the reference years 2024, 2025, and 2026, plus 65% of the HCFC baseline. The later baseline reference period gives Group 2 Parties a higher starting point that reflects their continuing HFC growth through the mid-2020s.

Why the baseline structure matters

The baseline calculation has two consequential design features. First, the inclusion of an HCFC-baseline component (15% for Non-Article 5, 65% for Article 5) means the Kigali baselines are higher than the actual HFC consumption in the reference years would suggest — reflecting the policy intent to allow continued HCFC-to-HFC substitution within a controlled envelope. Second, the use of CO₂e denomination (Annex F GWP-100 values) means a Party’s baseline depends not only on the physical tonnes consumed but on the substance mix — a country whose HFC consumption is skewed toward high-GWP substances (HFC-143a, HFC-125, R-404A, R-507A) has a numerically higher baseline than a country whose consumption is skewed toward lower-GWP substances (HFC-32, HFC-152a) for the same physical tonnage.

The Phase-Down Trajectory Tables

The amendment’s Article 2J sets out the consumption and production limits for each Party, in CO₂-equivalent terms, as a percentage of that Party’s baseline. The three group schedules below are reproduced from the operative amendment text.

Non-Article 5 (developed countries)

Article 5 Group 1 (most developing countries)

Article 5 Group 2 (high-ambient-temperature developing countries)

Production limits track the same schedule as consumption limits in most cases, with adjustments for legitimate trade (a Party may produce more than it consumes if it exports the difference to other Parties holding sufficient consumption headroom).

HFC CO₂e Savings — the 0.5°C Figure Unpacked

The most-quoted impact figure for the Kigali Amendment is “up to 0.5°C of avoided warming by 2100”. The number is not loose advocacy — it is a specific projection produced by the UNEP/WMO Scientific Assessment of Ozone Depletion (the 2018 quadrennial assessment, refined in the 2022 quadrennial assessment) using established atmospheric chemistry and integrated assessment modelling. Three points unlock the figure.

The baseline counterfactual is critical. The 0.5°C figure compares the Kigali phase-down trajectory against a no-Kigali counterfactual in which HFC consumption continues to grow on the trajectory implied by HCFC phase-out substitution patterns through to 2100. The counterfactual is not “zero policy” — the Montreal Protocol’s HCFC phase-out continues in the counterfactual — but it is a “no-HFC-control” counterfactual. The 0.5°C is therefore the marginal contribution of the Kigali phase-down on top of the underlying Montreal Protocol HCFC controls.

The radiative-forcing pathway runs through atmospheric concentrations. HFCs have atmospheric lifetimes ranging from a few months (HFC-152a) to 14 years (HFC-134a) to 270 years (HFC-23). Phasing down HFC emissions reduces atmospheric concentrations, and reduced concentrations reduce radiative forcing. The translation from cumulative-emissions reduction to peak-warming reduction is sensitive to the emission profile across the schedule, the lifetime weighting of the substance mix, and the climate sensitivity assumption.

Energy-efficiency co-benefits are excluded from the headline number. The 0.5°C figure captures direct HFC radiative-forcing reduction only. The Kigali Amendment is also associated with a significant indirect climate benefit because the transition to low-GWP refrigerants frequently coincides with energy-efficiency improvements in the redesigned equipment. UNEP and the International Energy Agency have estimated that the combined direct (HFC) plus indirect (efficiency) benefit could approach an additional 0.5°C of avoided warming if energy efficiency is fully captured in the transition. The “up to 1°C” formulation sometimes used in advocacy combines these direct and indirect effects.

Gases Covered — Annex F Group I and Group II

The Kigali Amendment creates a new Annex F to the Montreal Protocol listing the 18 controlled HFCs. Annex F is split into two groups: Group I contains 17 HFC substances and is subject to the standard phase-down schedules above; Group II contains HFC-23 separately, reflecting its unique properties (extremely high GWP-100 of 14,800 on the AR4 basis, atmospheric lifetime of 270 years, and primary production pathway as a byproduct of HCFC-22 manufacturing). Group II has its own dedicated control regime under Article 2J(6), which requires Parties to ensure that HFC-23 byproduct emissions from HCFC-22 production facilities are destroyed to the extent practicable.

The table below lists every Annex F substance with its chemical formula, IPCC AR4 GWP-100 (the value listed in Annex F itself and the operative basis for Kigali CO₂e math), IPCC AR5 GWP-100 (the value still widely used in UNFCCC national inventories), and IPCC AR6 GWP-100 (the value adopted by GHG Protocol Corporate Standard, CSRD ESRS E1-6, and SBTi from 2024 onward). Values are hardcoded to the cited primary sources.

The AR4 column is the value listed in Annex F and is the legally operative basis for all Kigali Amendment CO₂e calculations. The AR6 column is the operative value for corporate Scope 1 fugitive disclosure under ESRS E1-6 and SBTi for inventory year 2024 onward. The AR5 column is the value that remains in use across many UNFCCC national inventory submissions. For the live machine-readable IPCC AR6 GWP dataset used by GreenCalculus calculators, see IPCC AR6 GWP values.

What Kigali Does Not Cover

The Kigali Amendment’s scope is precisely the 18 substances in Annex F plus mixtures containing them. It is narrower than several adjacent regulatory regimes — a point of frequent confusion among practitioners assuming “Kigali covers all F-gases”.

• Hydrofluoroolefins (HFOs) — HFO-1234yf, HFO-1234ze(E), and related olefins are not Annex F substances. They are covered by national instruments where those instruments adopt broader scope (EU F-Gas Regulation 2024/573 Annex I covers HFOs above defined GWP thresholds; the U.S. AIM Act covers only the same 18 HFCs as Kigali).
• Perfluorocarbons (PFCs) — CF₄, C₂F₆, and other PFCs are not controlled under Kigali. They remain in scope of UNFCCC national-inventory reporting and of the EU F-Gas Regulation, but not of the Montreal Protocol.
• Sulphur hexafluoride (SF₆) — the highest-GWP commonly-used industrial gas (22,800 AR4, 25,200 AR6) is not a Kigali substance. SF₆ controls operate under the EU F-Gas Regulation and parallel national instruments, not under the Montreal Protocol.
• Nitrogen trifluoride (NF₃) — widely used in semiconductor manufacturing — is not a Kigali substance.
• Natural refrigerants — CO₂ (R-744), ammonia (R-717), and hydrocarbons (R-290, R-600a) are not controlled. Their use as Kigali-aligned substitutes is the policy intent.
• HFC byproduct emissions outside Group II treatment — HFC-23 from HCFC-22 production is explicitly controlled under Article 2J(6), but other accidental HFC byproduct emissions in chemical manufacturing are not separately controlled by Kigali (they fall to the operator’s national-instrument or corporate-disclosure obligations).

The Climate–ODS Intersection

The Kigali Amendment sits at a structural intersection that the original Montreal Protocol did not anticipate. HFCs are not ozone-depleting; their inclusion in the Montreal Protocol is a deliberate policy choice to use the Protocol’s well-functioning institutional machinery for a non-ozone climate purpose. The intersection has three operational consequences.

First, the baseline-substitution dynamic means that HFC controls cannot be designed in isolation from the ongoing HCFC phase-out. The 2007 Montreal Adjustment accelerated the HCFC phase-out and, in doing so, set the HFC growth trajectory the Kigali Amendment addresses. Future MOP decisions on HCFC servicing tails, HCFC essential-use exemptions, and HCFC stockpile management interact with the HFC schedule, particularly in Article 5 countries.

Second, the energy-efficiency co-benefit means that the climate impact of the Kigali transition depends on equipment-design choices that are partly outside the Protocol’s formal scope. Replacing R-410A with R-32 in a split air-conditioner saves CO₂e directly through lower-GWP refrigerant choice, but the same redesign typically delivers a 5–10% improvement in cooling efficiency, which saves indirect emissions through reduced electricity demand at grid emission factors. The TEAP and the International Energy Agency have repeatedly emphasised that the combined direct-plus-indirect climate benefit is roughly double the headline HFC-only number.

Third, the ozone-layer recovery linkage means that high-GWP HFC accumulation in the stratosphere is not climate-neutral with respect to the recovering ozone layer. The 2022 Scientific Assessment confirmed that the Antarctic ozone hole is on track to recover to 1980 conditions around 2066 if HCFC and Kigali commitments are met; significant non-compliance with Kigali would slow the recovery trajectory because warmer stratospheric temperatures (driven partly by HFC radiative forcing) interact with the polar ozone chemistry.

Technology Alternatives

The Kigali phase-down only works because technically mature low-GWP alternatives exist for most application categories. The TEAP’s Refrigeration, Air-Conditioning and Heat Pumps Technical Options Committee (RTOC) publishes the canonical alternatives assessment for each application; the short-list below summarises the practitioner-level state of the art as of May 2026.

Hydrofluoroolefins (HFOs) — the chemical successors

R-1234yf and R-1234ze(E) are the headline HFOs. AR4 GWP-100 of 4 and 7 respectively; AR6 GWP-100 of less than 1 for both. R-1234yf has replaced R-134a as the standard refrigerant in new passenger-car mobile air-conditioning systems globally. R-1234ze(E) is widely used in commercial chillers and as a foam blowing agent. Blends of HFO with HFC (R-454B, R-454C, R-513A, R-450A) deliver intermediate GWP values suitable for split-system air-conditioning, heat pumps, and commercial chillers. HFOs are not Annex F substances and therefore consume zero Kigali quota.

Hydrocarbons — R-290 (propane) and R-600a (isobutane)

R-600a dominates domestic refrigeration globally and has done since the late 1990s. R-290 is increasingly used in commercial plug-in refrigeration, monobloc heat pumps, and small split air-conditioners. Both have negligible GWP. The constraint is flammability (A3 safety classification under ISO 817), which limits charge sizes under residential and similar settings to roughly 1–1.5 kg per circuit under IEC 60335-2-40.

Ammonia — R-717

Dominant in industrial refrigeration, increasingly used in large commercial systems and district cooling. Zero GWP, zero ODP. Constraints are toxicity (B2L safety classification) and materials compatibility (corrosion of copper).

Carbon dioxide — R-744

Dominant in centralised supermarket refrigeration in cooler European climates; growing rapidly in heat-pump water heaters; increasingly used in commercial-scale air-conditioning. GWP of 1. The constraint is the high operating pressure (transcritical cycles at 80–100 bar discharge pressure).

High-ambient-temperature challenges

The Article 5 Group 2 designation reflects a genuine technical asymmetry: many low-GWP alternatives perform less efficiently at the 35–50°C ambient temperatures typical in Gulf-state and South Asian summers, and the equipment redesigns needed for high-ambient operation are still maturing. The TEAP’s 2022 progress report identified R-32 and R-454B as the principal current Group 2 transition refrigerants for residential air-conditioning, with R-1234yf and R-744 advancing for commercial applications. The longer Group 2 phase-down period to 2047 reflects the time needed for high-ambient-capable low-GWP equipment to reach full commercial maturity.

Ratification Status and Trade Consequences

As of the Ozone Secretariat’s most recent published ratification status (March 2025), 171 states and the European Union have ratified the Kigali Amendment. The Ozone Secretariat and UNEP are working toward universal ratification (all 198 Parties to the Montreal Protocol) by the time of MOP38, which convenes in October 2026 to mark the amendment’s tenth anniversary.

The amendment entered into force globally on 1 January 2019 after reaching the 20-Party threshold (the 20th instrument of ratification was deposited on 27 September 2017). Notable ratification milestones since then include the European Union (instrument deposited 27 September 2018), India (27 September 2021), and the United States (Senate consent 21 September 2022, instrument deposited 31 October 2022).

Trade discipline with non-Parties — Article 4B

The amendment’s most consequential enforcement mechanism is the trade-restriction regime under Article 4B. From 1 January 2033, Parties to the Kigali Amendment are required to ban imports of Annex F substances from non-Parties and exports of Annex F substances to non-Parties. The mechanism mirrors the trade-discipline provisions that drove near-universal ratification of the underlying Montreal Protocol — once a critical mass of Parties has ratified, the cost of remaining outside the Amendment (loss of HFC trade access with all ratifying Parties) becomes prohibitive for any country with HFC-dependent manufacturing or refrigerant-supply needs.

The 2033 date is significant for compliance planning: ratifying Parties have until that date to ensure their licensing systems under Article 4 of the underlying Protocol are extended to cover Annex F substances and their domestic enforcement architecture is capable of distinguishing Party from non-Party origin in import flows.

Holdouts and the path to universal ratification

The Parties to the Montreal Protocol that have not yet ratified the Kigali Amendment as of the most recent Ozone Secretariat status report are a small group concentrated in regions where domestic-implementation legislation is still in development. The Ozone Secretariat’s outreach programme provides technical and financial-cooperation assistance to these Parties via the Multilateral Fund and the Compliance Assistance Programme regional offices. Universal ratification by MOP38 (October 2026) is the operational target.

Implementing Laws by Jurisdiction

The Kigali Amendment creates obligations on States, not on private operators. The translation from treaty obligation to private-sector compliance occurs through domestic implementing legislation in each ratifying Party. The principal implementing instruments are summarised below.

European Union — Regulation (EU) 2024/573 (F-Gas Regulation 2024)

The EU’s implementing instrument is Regulation (EU) 2024/573, adopted on 7 February 2024 and applied from 11 March 2024. It substantially exceeds the EU’s bare Kigali commitments — the EU’s Annex VII trajectory drives bulk HFC supply to zero placing-on-market by 1 January 2050, far more ambitious than the 85% reduction the amendment requires of Non-Article 5 Parties by 2036. The regulation also bans specific high-GWP equipment categories under Annex IV. The UK applied the predecessor 2014 EU regulation until Brexit; Northern Ireland continues to apply the 2024 regulation under the Windsor Framework. See EU F-Gas Regulation 2024 for the full reference.

United States — the AIM Act 2020 and EPA implementing rules

The American Innovation and Manufacturing Act 2020 (codified at 42 U.S.C. § 7675), enacted as part of the Consolidated Appropriations Act 2021 on 27 December 2020, authorises the EPA to phase down HFC production and consumption by 85% by 2036 from a 2011–2013 baseline. The EPA Allowance Allocation Program (Final Rule of 23 September 2021, 86 FR 55116) operationalises the phase-down through a consumption and production allowance trading regime. The U.S. baseline is 302.5 million metric tons CO₂e. The AIM Act schedule: 10% reduction from 2022, 40% from 2024 (target value 60% of baseline), 70% from 2029, 80% from 2034, 85% from 2036. The schedule aligns precisely with the Kigali Non-Article 5 trajectory. The U.S. Senate consented to ratification on 21 September 2022 (vote 69–27), and the U.S. instrument of ratification was deposited on 31 October 2022.

United Kingdom — SI 2015/168 as amended

The Fluorinated Greenhouse Gases Regulations 2015 (Statutory Instrument 2015/168) incorporate the substantive provisions of the 2014 EU F-Gas Regulation into GB law and remain the operative instrument for Great Britain post-Brexit. The UK consulted on F-Gas regime reform in 2025; legislative reform is not yet complete. Northern Ireland continues to apply the EU 2024 regulation under the Windsor Framework. The UK ratified the Kigali Amendment in its own right on 14 March 2018.

China — HFC consumption and production controls

China ratified the Kigali Amendment on 17 June 2021 and is an Article 5 Group 1 Party. The principal domestic instrument is the Regulation on the Management of Ozone-Depleting Substances (2010, amended) as extended to HFCs by the Ministry of Ecology and Environment, with HFC consumption frozen at the 2020–2022 baseline from 1 January 2024 in line with the Group 1 schedule. China is the world’s largest HFC producer and the largest single Party contribution to the Kigali phase-down impact.

India — Group 2 phase-down schedule

India ratified the Kigali Amendment on 27 September 2021 and is an Article 5 Group 2 Party. The principal domestic instrument is the Ozone-Depleting Substances (Regulation and Control) Rules under the Environment (Protection) Act 1986, as extended to HFCs. India’s baseline reference period is 2024–2026 and the freeze step takes effect on 1 January 2028.

Other major jurisdictions

Japan implements through the Act on Rational Use and Proper Management of Fluorocarbons (2015, amended). Canada implements through the Ozone-depleting Substances and Halocarbon Alternatives Regulations (SOR/2016-137). Australia implements through the Ozone Protection and Synthetic Greenhouse Gas Management Act 1989, as amended for HFC controls. Brazil, Indonesia, South Africa, Mexico, and other Group 1 Parties are at varying stages of domestic-implementation rule development under the technical and financial assistance of the Multilateral Fund.

The Multilateral Fund

The Multilateral Fund for the Implementation of the Montreal Protocol (MLF) is the financing instrument through which Non-Article 5 Parties cover the incremental costs of Article 5 Parties’ compliance with Protocol obligations. The fund was established by the London Amendment in 1990, became operational in 1991, and has channelled cumulative funding of more than four billion USD to Article 5 Parties through to 2025.

The MLF’s relevance to Kigali is twofold. First, the fund’s triennial replenishments (the most recent for 2024–2026) explicitly include funding lines for HFC phase-down implementation in Article 5 Parties, on top of the continuing HCFC phase-out funding. Second, the MLF Executive Committee approves country-level Kigali implementation plans (Kigali HFC Initial Reduction Plans, or KIRPs) on a project-by-project basis, with the funded activities including refrigerant-recovery infrastructure, technician certification programmes, equipment-conversion subsidies, demonstration projects for low-GWP alternatives in high-ambient-temperature applications, customs-officer training for the licensing system, and national policy and regulatory development support.

The MLF’s record on HCFC phase-out compliance is the institutional precedent that gave Article 5 Parties confidence to ratify the Kigali Amendment: Article 5 Parties have substantially met their HCFC phase-out obligations under the 2007 Montreal Adjustment, with no major non-compliance findings against Article 5 Parties on the HCFC schedule. The same institutional architecture is being applied to HFC implementation.

Kigali vs EU F-Gas vs U.S. AIM Act — the Three-Column Comparison

Practitioners managing cross-border refrigerant supply or multinational equipment fleets need to navigate three overlapping but distinct phase-down schedules. The table below maps the three trajectories side by side. The Kigali column reflects the Non-Article 5 schedule (the relevant comparator for the EU and U.S. trajectories).

The headline takeaway: the EU 2024 regulation is substantially more ambitious than the bare Kigali Non-Article 5 schedule (zero by 2050 vs 15% of baseline at 2036), while the U.S. AIM Act tracks the Kigali Non-Article 5 schedule exactly. The EU is therefore on a unilaterally faster trajectory than the international floor; the U.S. trajectory is the international floor.

From Kigali to Corporate Scope 1 Inventory

For sustainability officers, the Kigali Amendment is the international-law root of the most-leveraged Scope 1 abatement opportunity in service-intensive sectors. Refrigerant leakage from owned or operated equipment is the canonical Scope 1 fugitive emission under the GHG Protocol Corporate Standard. Every Annex F substance is a Scope 1 fugitive emission source when it leaks; every kilogram of leaked HFC translates into CO₂e at the substance’s GWP-100 value (AR6 for corporate disclosure; AR4 for Kigali and EU F-Gas compliance reporting).

The disclosure chain — treaty to data

The path from international treaty obligation to corporate data line runs as follows: the Kigali Amendment binds the Party (the EU, the U.S., the UK, etc.); the Party enacts a domestic implementing instrument (EU F-Gas Regulation 2024/573, U.S. AIM Act, UK SI 2015/168); the implementing instrument creates direct obligations on private operators including the requirement to maintain an equipment log of refrigerant additions and recoveries; the equipment log captures the actual refrigerant leakage at each piece of equipment in physical kilograms; the kilograms are converted to CO₂e at the operator’s applicable GWP basis (AR4 for the F-Gas regulatory submission, AR6 for the ESRS E1-6 disclosure); the AR6 CO₂e values flow into the Scope 1 fugitive line of the corporate inventory — see our refrigerant leakage methodology for the Tier 1, mass-balance, and Tier 2 lifecycle methods.

The chain is fully traceable from the international treaty at the top to the audited disclosure line at the bottom, with the equipment log under domestic implementing law as the primary data anchor. See Scope 1 emissions for the underlying classification and GHG Protocol Corporate Standard for the three calculation tiers (mass-balance, sales-based, screening) applicable to refrigerant fugitive emissions.

Worked Example — Supermarket Refrigeration R-404A to R-744 Transition

The following walks through the Kigali-aligned climate impact of a refrigerant transition at a single supermarket site. The example is stylised but representative of European food-retail decarbonisation programmes.

The scenario

A regional supermarket operator runs a centralised commercial refrigeration system at a flagship store. The legacy installation (installed 2015, pre-Kigali implementing law) uses 850 kg of R-404A — a 50:44:4 mass blend of HFC-125, HFC-143a, and HFC-134a. Annual measured leakage from the F-Gas equipment log is 8.5% of installed charge, or 72.25 kg of R-404A per year. In 2027 the system reaches end-of-economic-life and is replaced with a transcritical CO₂ (R-744) system holding 280 kg of CO₂ at operating charge; annual measured leakage from the new system is 12% of charge or 33.6 kg of CO₂ per year.

Pre-transition (R-404A) annual fugitive Scope 1 emissions

R-404A AR6 GWP-100 = 4,728 (IPCC AR6 WGI Table 7.SM.7).

72.25 kg × 4,728 = 341,598 kg CO₂e = 341.60 tonnes CO₂e per year.

Post-transition (R-744) annual fugitive Scope 1 emissions

CO₂ (R-744) AR6 GWP-100 = 1.

33.6 kg × 1 = 33.6 kg CO₂e = 0.034 tonnes CO₂e per year.

The Scope 1 reduction

The refrigerant transition eliminates 341.60 − 0.034 = 341.57 tonnes CO₂e per year of Scope 1 fugitive emissions at this single site. The reduction is 99.99% of the original refrigerant CO₂e line. The transition cost (typical 30–50% capex premium over a like-for-like HFC replacement) is offset over 5–10 years by lower refrigerant servicing costs (CO₂ recharges cost a fraction of high-GWP HFC recharges), energy-efficiency gains (transcritical CO₂ systems are typically 5–15% more efficient than R-404A systems in cooler European climates), and the avoided exposure to the EU F-Gas Annex IV servicing-ban on virgin HFCs of GWP ≥ 2,500 from 1 January 2025 and on reclaimed material of GWP ≥ 2,500 in most stationary applications from 1 January 2030.

The Kigali link

This transition is precisely what the Kigali Amendment is designed to drive. R-404A (R-125/R-143a/R-134a blend) is composed entirely of Annex F Group I substances; the Kigali Non-Article 5 phase-down trajectory, operationalised through the EU F-Gas Regulation, makes continued R-404A supply progressively more expensive and ultimately impossible. R-744 (CO₂) is not an Annex F substance and consumes no Kigali quota. The transition is one of the highest-leverage corporate Scope 1 actions available to a refrigeration-intensive operator and is one of the policy outcomes that underpins the 0.5°C avoided-warming projection.

Note: values are illustrative. Use site-specific F-Gas equipment log data, actual installed charge, measured leak rates, and current AR6 GWP-100 values for any real reporting position.

Kigali in the CSRD ESRS E1 Disclosure Chain

Refrigerant fugitive emissions originating in Kigali-controlled substances flow into the CSRD disclosure stack through ESRS E1 Climate Change. The reporting chain has three principal touchpoints for in-scope undertakings.

ESRS E1-6 gross Scope 1 emissions

ESRS E1-6 requires disclosure of gross Scope 1 GHG emissions for the reporting year, broken down by GHG and by activity where applicable. Fugitive HFC emissions are a Scope 1 line item, calculated in CO₂e using the most recent IPCC GWP-100 values (AR6 in practice for any reporting year from 2024 onward). The data source is the equipment log under the operator’s applicable F-Gas instrument, aggregated across all sites within the consolidation boundary. See CSRD / ESRS E1 for the full reference.

ESRS E1-1 climate transition plan

The transition plan disclosure is the strategic-narrative location where Kigali-exposed undertakings describe how the Kigali phase-down trajectory and the relevant national implementing instrument interact with their equipment-replacement strategy. The disclosure expectation is to articulate the operator’s plan to migrate refrigeration, air-conditioning, and heat-pump equipment from Annex F HFCs to low-GWP alternatives on a timetable aligned with both regulatory deadlines and the broader corporate decarbonisation pathway.

ESRS E1-3 actions, E1-4 targets

Specific actions taken to reduce Annex F HFC emissions — equipment-replacement programmes, automatic-leak-detection retrofits, recovery-rate improvement initiatives — are disclosed under E1-3 with associated capex and opex. Where the operator has set a Scope 1 reduction target (SBTi-aligned or otherwise) that includes fugitive emissions, the target is disclosed under E1-4.

Kigali, SBTi, and Near-Term Targets

For operators committed to Science Based Targets, fugitive HFC emissions from Annex F substances are a Scope 1 line item that must be included in the near-term target boundary. The SBTi Corporate Net-Zero Standard requires Scope 1 + 2 reductions of at least 42% by 2030 from a recent base year for 1.5°C-aligned near-term targets. The Kigali phase-down trajectory provides an external reference rate (40% by 2024 and 70% by 2029 from the 2011–2013 baseline for Non-Article 5 Parties) that gives refrigerant-intensive operators a natural pathway to deep Scope 1 cuts. See SBTi Corporate Net-Zero Standard and the SBTi readiness checklist.

The fugitive-emission abatement lever is particularly powerful because it interacts with the regulatory trajectory: equipment that must be replaced anyway under EU Annex IV or U.S. AIM Act Technology Transition rules can be replaced with low-GWP alternatives at minimal stranded-asset cost, with the SBTi-relevant CO₂e reduction captured as a co-benefit of compliance investment. Sequencing the corporate decarbonisation plan with the regulatory natural-replacement cycle is the practitioner-level optimisation.

HFC Trade Measures — Article 4B Imports and Exports

The Kigali Amendment’s trade-discipline regime sits in two places. The licensing system under the underlying Montreal Protocol’s Article 4B already requires Parties to operate a licensing system for the import and export of all controlled substances; the Kigali Amendment extends this to Annex F substances. The trade-restriction provisions specifically targeting non-Parties operate from 1 January 2033.

The licensing system

Each Party must operate a system requiring import and export licences for Annex F substances, with the licences cross-checked against the Party’s consumption and production headroom. The licensing system is the operational mechanism by which the Article 7 reporting obligation is reconciled to actual customs flows. Practical implementation typically integrates the F-gas licensing system with the Party’s customs single-window infrastructure (the EU’s ECHA F-Gas Portal customs data link is the most-developed example).

HFC trade with non-Parties from 1 January 2033

From 1 January 2033, Parties must prohibit imports of Annex F substances from non-Parties and exports of Annex F substances to non-Parties. The mechanism replicates the trade-discipline provisions of the underlying Protocol’s Article 4 that drove near-universal ratification of the CFC and HCFC controls. The 2033 date gives ratifying Parties almost a decade to extend their licensing systems and to update customs nomenclature to capture Annex F substances by HS code.

Customs classification

The Harmonised System (HS) classification of HFCs is principally HS chapter 29 (organic chemicals), with the relevant subheadings 2903.41 through 2903.49 covering most Annex F substances. Customs enforcement under Article 4B requires Parties to identify Annex F substances at the level of the substance, not just the chapter — a customs declaration of “HS 2903.41 HFCs” without substance-level identification is insufficient for Kigali compliance verification.

Temperature and Climate Science — IPCC AR6 Context

The Kigali Amendment’s headline climate impact — up to 0.5°C of avoided warming by 2100 from the HFC phase-down alone — sits inside the broader IPCC AR6 climate-science framework. Three observations contextualise the figure.

First, the AR6 Working Group I report assigns short-lived climate forcers (a category that includes most HFCs, despite their multi-year atmospheric lifetimes being “short” only relative to CO₂) a distinct mitigation pathway separate from the cumulative-CO₂-budget framing that anchors the 1.5°C and 2°C Paris Agreement targets. Reducing short-lived forcers, including HFCs, reduces peak warming directly and offers near-term temperature benefits that cumulative-CO₂ reductions can take decades to deliver. See IPCC AR6.

Second, the 0.5°C figure is sensitive to the substance mix actually phased down. A phase-down that disproportionately reduces high-GWP species (R-404A, HFC-143a, HFC-23) delivers more climate benefit per physical tonne than a phase-down skewed toward lower-GWP species (HFC-32, HFC-152a). The Kigali architecture’s CO₂e denomination of consumption and production limits is the policy design that incentivises producers to lean into the lower-GWP species first — precisely the optimisation the 0.5°C projection assumes.

Third, the energy-efficiency co-benefit not captured in the 0.5°C headline is potentially of comparable magnitude. The TEAP and IEA joint analyses have estimated that an HFC transition delivered with the energy-efficiency improvements that are typically available at refrigerant-redesign moments could approximately double the direct climate impact, bringing the combined direct-plus-indirect benefit to the order of 1°C avoided warming.

Kigali and the Paris Agreement

The Kigali Amendment and the Paris Agreement are complementary, not overlapping. The Paris Agreement (2015) is the UNFCCC’s headline instrument committing Parties to hold global average temperature increase well below 2°C and pursuing efforts to limit it to 1.5°C above pre-industrial levels. It does so through nationally determined contributions (NDCs) covering economy-wide emissions including HFCs. The Kigali Amendment sits inside the Montreal Protocol architecture, controlling a specific class of substances (Annex F HFCs) through a phase-down schedule defined in CO₂e terms.

The complementarity

The Kigali Amendment delivers HFC emission reductions directly through binding multilateral commitments. The Paris Agreement’s NDCs typically include economy-wide CO₂e targets that count HFC reductions, but the Paris Agreement does not by itself impose a quantitative HFC schedule. The result is that Kigali compliance contributes mechanically to a Party’s NDC achievement without that Party needing to make separate HFC-specific commitments at the UNFCCC level.

The “extra” warming avoided

The 0.5°C avoided warming projected for the Kigali phase-down is additional to the warming avoided through Paris-Agreement-driven CO₂ mitigation. The two instruments work together: Paris drives CO₂ down through long-cycle decarbonisation of energy and land; Kigali drives HFCs down through the near-term refrigerant-transition lever; the combined trajectory keeps total warming within the Paris Agreement’s temperature goals more reliably than either instrument alone.

Sector Notes

Commercial refrigeration — food retail

The single largest Annex F consumption sector in most economies. Centralised supermarket refrigeration systems historically used R-404A, R-407A, or R-507A, all containing HFC-125, HFC-143a, and HFC-134a (Annex F Group I substances). The transition path is to transcritical CO₂ for new centralised installations in cooler climates, to propane or CO₂ for plug-in commercial cabinets, and to lower-GWP HFC/HFO blends for retrofits to existing systems. The Kigali Non-Article 5 trajectory has driven the European food-retail sector through a substantial proportion of its system fleet transition by 2024–2026; Article 5 Group 1 countries are at earlier stages.

Building HVAC — commercial and residential

R-410A (a 50:50 HFC-32 / HFC-125 blend, both Annex F substances) dominated new commercial HVAC installations globally through the mid-2020s. The transition is to R-32 (single substance, GWP 675 AR4), to R-454B and similar HFC/HFO blends, and increasingly to R-290 (propane, not an Annex F substance) in smaller units. The Kigali phase-down drives R-410A out of new equipment markets in Non-Article 5 jurisdictions through the 2027–2035 window, with Article 5 Group 1 following a 5–10 year lag and Article 5 Group 2 a 10–15 year lag.

Industrial refrigeration

Long-standing ammonia (R-717, non-Annex F) dominance for industrial-scale systems means industrial refrigeration is the least Kigali-exposed of the major sectors. CO₂ and HFO refrigerants cover the niche applications where ammonia is unsuitable.

Mobile air-conditioning

HFC-134a (Annex F) was the dominant MAC refrigerant globally through the mid-2010s. The transition to R-1234yf (HFO, non-Annex F) is now substantially complete in Non-Article 5 markets and progressing in Article 5 markets. CO₂ is used in some heat-pump cabin-heating variants on electric vehicles.

Foam blowing

HFC-245fa, HFC-365mfc, and HFC-152a (all Annex F) were widely used as foam blowing agents. The transition is to hydrocarbons (pentane, cyclopentane), HFOs (HFO-1336mzz), and CO₂.

Aerosols — technical and medical

HFC-134a and HFC-227ea (Annex F) are used in pharmaceutical metered-dose inhalers (MDIs) and in some technical aerosols. The MDI transition is medically sensitive and has received specific essential-use treatment under the MOP and individual Party regulatory frameworks.

Fire suppression

HFC-227ea and HFC-125 (Annex F) are used in clean-agent fire-suppression systems. The transition is to inert gases (IG-541, IG-55, IG-100), water mist, and fluoroketones, with the latter not being Annex F substances.

Solvents and other specialty applications

HFC-43-10mee, HFC-365mfc, and HFC-245fa (Annex F) are used as electronic-grade solvents and in specialty cleaning. The transition is to HFO solvents, low-GWP fluorinated solvents, and aqueous cleaning where technically feasible.

Decision Tree: Does Kigali Apply to My Company’s HFC Use?

For an operator working through whether the Kigali Amendment (through its domestic implementing instrument) applies to a specific facility or piece of equipment, the following decision sequence captures the principal scope tests.

1. Does the equipment or process use a substance listed in Annex F? Annex F covers 18 HFCs (HFC-23, HFC-32, HFC-41, HFC-125, HFC-134, HFC-134a, HFC-143, HFC-143a, HFC-152, HFC-152a, HFC-161, HFC-227ea, HFC-236cb, HFC-236ea, HFC-236fa, HFC-245ca, HFC-245fa, HFC-365mfc, HFC-43-10mee) plus mixtures containing any of these. If no — Kigali does not directly apply (though the domestic implementing instrument may have broader scope).
2. Which Party’s jurisdiction does the activity occur in? Identify the Party. Determine whether that Party is Non-Article 5, Article 5 Group 1, or Article 5 Group 2. The applicable schedule depends on the group designation.
3. Has that Party ratified the Kigali Amendment? If yes — the Party’s domestic implementing instrument applies (EU F-Gas Regulation, U.S. AIM Act, UK SI 2015/168 as amended, etc.). If no — the Party’s domestic instrument (if any) is the operative rule, and after 1 January 2033 the activity may be affected by Article 4B trade restrictions imposed by ratifying Parties.
4. Is the activity import, production, consumption, or end-use? Different obligations attach to different roles. Producers and importers are subject to the headline consumption/production limits via allowance or quota systems. End-users (operators of equipment) are subject to containment, recovery, certification, and recordkeeping obligations under domestic implementing instruments.
5. Is the substance virgin, recycled, or reclaimed? Reclaimed material is treated differently from virgin material under most domestic regimes, with phased-in servicing restrictions on high-GWP virgin and reclaimed material. The treatment can be the deciding factor for ongoing maintenance of legacy high-GWP equipment.
6. What is the cumulative annual consumption? Reporting thresholds typically activate at 1 tonne for placing-on-market activities and at 100 tonnes CO₂e for equipment operators (specific thresholds vary by Party). Below threshold, the activity is in regulatory scope but not separately reportable.

Decision Tree: Which Kigali-Aligned Alternative Refrigerant?

For a project specifying a new system in a Kigali-ratifying jurisdiction, the alternative-refrigerant decision turns on application category, capacity, safety classification, GWP target, ambient-temperature operating range, and equipment lifetime relative to the phase-down trajectory.

1. Application category and capacity — identify the applicable Annex IV row (in EU jurisdictions) or AIM Act Technology Transitions rule (in the U.S.) or equivalent in other Parties. The row gives the operative deadline and GWP threshold for new placing-on-market.
2. Long-term GWP target — for equipment with 15–25 year design life, specify a refrigerant compatible with the 2036 Non-Article 5 endpoint (15% of baseline) or the 2045–2047 Article 5 endpoints (20% of baseline). In practice, this means a single-substance GWP below 150 or a natural refrigerant.
3. Safety classification constraints — A1 (non-flammable, non-toxic) is the broadest. A2L (mildly flammable, e.g. R-32, R-454B, R-1234yf) requires installation-design compliance with EN 378 or IEC 60335-2-40. A3 (flammable, e.g. R-290, R-600a) imposes charge-size limits. B2L (toxic, mildly flammable, e.g. R-717 ammonia) restricted to industrial settings.
4. Ambient-temperature operating range — in high-ambient-temperature applications (Group 2 countries, plus tropical commercial cooling), some low-GWP alternatives perform less efficiently at 35–50°C condensing temperatures. The TEAP RTOC guidance is the authoritative reference for high-ambient suitability.
5. Equipment-charge size constraints — natural refrigerant limits under safety standards may require multi-circuit design or a chiller approach for larger commercial applications.
6. Local availability of certified service infrastructure — in Article 5 countries especially, the availability of certified technicians and recovery equipment for the chosen alternative may be the practical decision-maker. MLF-funded technician certification programmes are progressively expanding the available supply.

Common Misinterpretations

Common Reporting Errors

1. Mixing GWP bases. Computing Kigali consumption (or EU F-Gas Annex VI math) using AR6 values, or computing ESRS E1-6 Scope 1 fugitive disclosure using the Annex F AR4 values. Both produce wrong numbers for their respective uses.
2. Confusing baseline year with reference period. The Non-Article 5 baseline is the average over 2011–2013, not the value in 2013 alone. The same applies to the Article 5 Group 1 reference period (2020–2022) and Group 2 reference period (2024–2026).
3. Omitting the HCFC baseline component. The baseline includes 15% of HCFC baseline (Non-Article 5) or 65% of HCFC baseline (Article 5 Group 1 and Group 2). Omitting it understates the operative baseline.
4. Treating HFOs as Annex F substances. HFO-1234yf, HFO-1234ze(E), and related HFOs are not Annex F substances. They consume zero Kigali quota and are not subject to the phase-down. Including them in Kigali consumption math is a category error.
5. Conflating consumption and production. Kigali sets separate (parallel) limits for consumption and production. A Party can have headroom on one and constraint on the other; a producer-importer with significant export trade may face different effective constraints from a consumption-only operator.
6. Missing the HFC-23 byproduct destruction obligation. Article 2J(6) requires Parties to ensure HFC-23 byproduct emissions from HCFC-22 production are destroyed to the extent practicable. This is a specific Group II obligation that is sometimes overlooked in implementing legislation.
7. Treating reclaimed material as outside the consumption envelope. Different jurisdictions treat reclaimed HFC material differently in their domestic implementing instruments. Under most regimes reclaimed material does not consume quota but is subject to use restrictions on high-GWP species in defined applications.
8. Reporting at the substance level when the activity is in a blend. R-404A, R-407C, R-410A, and other blends contain multiple Annex F substances. CO₂e calculations must apportion to each constituent substance at its Annex F GWP-100 value.
9. Confusing Article 5 status with development status. Article 5 designation under the Montreal Protocol is a defined legal status under the Protocol, not a synonym for “developing country” in general parlance. Some Parties commonly described as developing are Non-Article 5; some Article 5 Parties are middle-income.
10. Assuming national reporting equals corporate reporting. The Article 7 reporting obligation is on the Party (the State), not on private operators. Private-operator reporting obligations arise only from the domestic implementing instrument, and the data items differ.

Implementation Workflow

For a multi-jurisdictional operator implementing a Kigali-aligned refrigerant strategy from a fresh start, the practical workflow runs as follows.

1. Equipment inventory and substance classification (4–12 weeks). Identify every refrigerant-containing equipment item across the operational footprint. Record refrigerant identity at the substance level. Flag every Annex F substance for Kigali alignment. Convert installed charge masses to CO₂e using both AR4 (for regulatory reporting) and AR6 (for corporate disclosure) values.
2. Jurisdictional mapping (2–4 weeks). Identify the Party in which each site is located. Determine Non-Article 5 / Article 5 Group 1 / Article 5 Group 2 status. Identify the applicable domestic implementing instrument and its current phase-down step. Flag sites where the domestic instrument is stronger than the bare Kigali schedule (notably EU jurisdictions under Annex IV).
3. Replacement-strategy plan (4–8 weeks). Identify equipment likely to be affected by upcoming Annex IV / AIM Act / equivalent ban deadlines and by servicing prohibitions on high-GWP material. Sequence replacement to align with natural equipment-replacement cycles and with the corporate decarbonisation pathway.
4. Procurement-policy update (2–4 weeks). Update equipment specification standards to require low-GWP refrigerants for new installations. Set GWP thresholds that anticipate the next Annex IV step or AIM Act Technology Transition rule.
5. Technician and contractor verification (2–4 weeks). Verify that all contractors performing refrigerant interventions hold current certification under the applicable domestic scheme. Maintain a register of certified contractors by site.
6. Equipment log and recordkeeping infrastructure (2–4 weeks). Establish a single corporate equipment log capturing the data elements required by the domestic implementing instruments across all sites. Build the AR4 (regulatory) and AR6 (disclosure) parallel CO₂e calculation feeds.
7. Annual reporting cycle. Each year: aggregate the equipment-log data, compute annual fugitive emissions in both GWP bases, submit regulatory reports where thresholds are crossed, feed the AR6 inventory into ESRS E1-6 disclosure and SBTi target tracking. Reconcile the corporate AR6 figure against the regulatory AR4 figure with a clear documentary trail of the basis difference.
8. Periodic review (annually or on major regulatory milestone). Refresh the strategy against the upcoming Kigali phase-down step (next major Non-Article 5 step is 2029 to 30% of baseline; next major Article 5 Group 1 step is 2029 freeze; next major Group 2 step is 2028 freeze). Refresh against domestic-instrument revisions and against any MOP decisions adjusting the schedule.

Future Evolution — MOP38 and Beyond

Three trajectories will shape the Kigali landscape over the coming decade.

Universal ratification by MOP38 (October 2026). The Ozone Secretariat’s operational target is to bring all 198 Parties to the Montreal Protocol into Kigali ratification by the amendment’s tenth anniversary. As of March 2025, 171 states plus the EU have ratified; the remaining holdouts are concentrated in jurisdictions where domestic implementing legislation is still under development. The diplomatic and financial-cooperation push through 2025–2026 is the principal near-term focus.

Compliance reviews against the early phase-down steps. The first Article 5 Group 1 freeze (2024) and the first Article 5 Group 2 baseline period (2024–2026) are now under way. The Implementation Committee’s reviews of national reporting through 2025–2027 will surface the first set of compliance findings for the new Annex F controls. The pattern of those findings — whether non-compliance is concentrated in data accuracy, in absolute quantities, or in licensing-system implementation — will drive the Multilateral Fund’s technical-assistance prioritisation for the next replenishment.

The HFO and PFAS interaction. The hydrofluoroolefins that are the principal chemical successors to Annex F HFCs are subject to growing scrutiny under PFAS regulation in the EU and elsewhere, on the basis that HFOs decompose in the atmosphere to trifluoroacetic acid (TFA) and related persistent fluorinated compounds. The interaction between the Kigali Amendment’s climate-focused architecture and the PFAS framework’s broader-environmental-impact lens is an emerging policy question. MOP-level discussion of this interaction is anticipated through the late 2020s and may influence the next major substance-list review.

Frequently Asked Questions

Sources and References

Every numerical claim and methodological statement in this article reconciles to the primary sources below.

Primary international sources

• United Nations Environment Programme, Kigali Amendment to the Montreal Protocol on Substances that Deplete the Ozone Layer, adopted at MOP28 in Kigali, Rwanda, 15 October 2016; deposited with the UN Secretary-General 17 October 2016; entered into force 1 January 2019.
• United Nations Environment Programme, Montreal Protocol on Substances that Deplete the Ozone Layer, adopted 16 September 1987, entered into force 1 January 1989, with London (1990), Copenhagen (1992), Montreal (1997), Beijing (1999), and Kigali (2016) amendments.
• Vienna Convention for the Protection of the Ozone Layer, adopted 22 March 1985.
• Ozone Secretariat, Handbook for the Montreal Protocol on Substances that Deplete the Ozone Layer, consolidated edition (current edition incorporating all adopted amendments and adjustments through MOP36).
• Ozone Secretariat, Status of Ratification of the Kigali Amendment, periodic updates (most recent referenced: March 2025).
• UN Treaty Collection, Chapter XXVII.2.f — Amendment to the Montreal Protocol on Substances that Deplete the Ozone Layer, depositary records.
• Multilateral Fund Secretariat, Executive Committee Decisions, quarterly meeting reports.
• UNEP Ozone Secretariat, Decisions XXIX/3, XXX/1, XXXI/11, XXXIV/22, XXXV/25, XXXVI/21 on the Status of Ratification of the Kigali Amendment.

Scientific basis

• WMO/UNEP, Scientific Assessment of Ozone Depletion: 2018, Global Ozone Research and Monitoring Project Report No. 58, Geneva, 2018.
• WMO/UNEP, Scientific Assessment of Ozone Depletion: 2022, GAW Report No. 278, Geneva, 2022.
• UNEP TEAP, Refrigeration, Air-Conditioning and Heat Pumps Technical Options Committee (RTOC) Assessment Report 2022.
• IPCC, AR6 Working Group I Contribution to the Sixth Assessment Report — Chapter 7 and Table 7.SM.7 (GWP-100 values), 2021.
• IPCC, AR5 Working Group I Contribution to the Fifth Assessment Report — Table 8.A.1 (GWP-100 values), 2013.
• IPCC, AR4 Working Group I Contribution to the Fourth Assessment Report — Chapter 2.10 and Table 2.14 (GWP-100 values; basis for Annex F of the Kigali Amendment), 2007.
• IPCC, 2006 IPCC Guidelines for National Greenhouse Gas Inventories — Volume 3, Chapter 7 (Emissions of Fluorinated Substitutes for Ozone-Depleting Substances).
• IEA & UNEP, Cooling Emissions and Policy Synthesis Report, joint analysis on combined Kigali and energy-efficiency climate impact.

Domestic implementing instruments

• European Parliament and Council, Regulation (EU) 2024/573 of 7 February 2024 on fluorinated greenhouse gases, amending Directive (EU) 2019/1937 and repealing Regulation (EU) No 517/2014, OJ L of 20 February 2024.
• U.S. Congress, American Innovation and Manufacturing Act of 2020, codified at 42 U.S.C. § 7675 (enacted as Division S of the Consolidated Appropriations Act 2021, P.L. 116-260, signed 27 December 2020).
• U.S. EPA, Phasedown of Hydrofluorocarbons: Establishing the Allowance Allocation and Trading Program under the AIM Act, Final Rule, 86 FR 55116 (5 October 2021), and subsequent Allowance Allocation Rules.
• U.S. EPA, Phasedown of Hydrofluorocarbons: Restrictions on the Use of HFCs Under the AIM Act Subsection (i) Technology Transitions Rules, multiple Final Rules 2023–2024.
• UK Department for Environment, Food and Rural Affairs, The Fluorinated Greenhouse Gases Regulations 2015 (Statutory Instrument 2015/168) as amended.
• UK Government, UK F-Gas Regulation: consultation on reform, 2025.
• China Ministry of Ecology and Environment, Regulation on the Management of Ozone-Depleting Substances (2010, amended) as extended to HFCs.
• Government of India, Ozone-Depleting Substances (Regulation and Control) Rules under the Environment (Protection) Act 1986, as extended to HFCs.
• Japan, Act on Rational Use and Proper Management of Fluorocarbons (2015, amended).
• Canada, Ozone-depleting Substances and Halocarbon Alternatives Regulations (SOR/2016-137).

Adjacent corporate disclosure frameworks

• WRI & WBCSD, The Greenhouse Gas Protocol Corporate Accounting and Reporting Standard, revised edition.
• European Sustainability Reporting Standards, ESRS E1 (Climate change), EFRAG, 2023.
• Science Based Targets initiative, Corporate Net-Zero Standard.

Technical safety standards

• EN 378-1 to EN 378-4, Refrigerating systems and heat pumps — Safety and environmental requirements.
• IEC 60335-2-40, Household and similar electrical appliances — Safety — Particular requirements for electrical heat pumps, air-conditioners and dehumidifiers.
• ISO 817, Refrigerants — Designation and safety classification.

Related GreenCalculus reference pages

• EU F-Gas Regulation 2024
• GHG Protocol Corporate Standard
• GHG Protocol Scope 3 Standard
• GHG Protocol Scope 2 Guidance
• CSRD / ESRS E1
• SBTi Corporate Net-Zero Standard
• ISO 14064-1
• IPCC AR6
• IPCC 2006 Guidelines
• UK DEFRA Emission Factors
• ISO 14067 Product Carbon Footprint
• ISO 14040 / 14044 LCA
• BS EN 15978 Whole-Life Carbon for Buildings
• TCFD Recommendations
• RE100 Technical Criteria
• GHG Protocol Land Sector and Removals Standard
• Global warming potential
• CO₂e — carbon dioxide equivalent
• Scope 1 emissions
• Scope 2 emissions
• Scope 3 emissions
• Methane (CH₄)
• Nitrous oxide (N₂O)
• IPCC AR6 GWP values
• DEFRA emission factors
• IEA grid emission factors 2026
• Natural gas combustion methodology
• Scope 2 electricity methodology
• Scope 2 market-based methodology
• Scope 1 combustion calculator
• Scope 2 electricity calculator
• SBTi near-term target calculator
• SBTi readiness checklist

What changed in this revision

Updated 11 May 2026. Initial publication. Reflects the Kigali Amendment as it stands in May 2026: amendment adopted at MOP28 in Kigali, Rwanda on 15 October 2016; deposited with the UN Secretary-General 17 October 2016; entered into force 1 January 2019; 171 states and the European Union ratified as of the March 2025 Ozone Secretariat status report; universal ratification target by MOP38 in October 2026; the three-group differentiated phase-down architecture (Non-Article 5 to 15% of baseline by 2036, Article 5 Group 1 to 20% by 2045, Article 5 Group 2 to 20% by 2047); the 18-substance Annex F (Group I: 17 HFCs; Group II: HFC-23); the CO₂e-denominated consumption and production limits using GWP-100 values listed in Annex F (drawn from IPCC AR4); the 0.5°C avoided warming projection from the UNEP/WMO Scientific Assessment of Ozone Depletion (2018 and 2022 quadrennial reports); the Article 4B trade-restriction regime applying to non-Parties from 1 January 2033; the Multilateral Fund’s role in financing Article 5 implementation; the principal domestic implementing instruments (EU Regulation 2024/573, U.S. AIM Act 2020 and EPA Allowance Allocation Program, UK SI 2015/168 as amended, China and India domestic instruments); the three-column comparison of Kigali Non-Article 5 / EU F-Gas / U.S. AIM Act schedules; the GHG Protocol Corporate Standard’s classification of refrigerant leakage as Scope 1 fugitive emissions; the CSRD ESRS E1-6 disclosure expectation of AR6 GWP-100 values; IPCC AR4 / AR5 / AR6 GWP-100 values for all 18 Annex F substances; and the technical safety standards (EN 378, IEC 60335-2-40, ISO 817) that govern installation of low-GWP alternative refrigerants.