(H)CFCs are ozone depleting substances (ODSs) and have been successfully been phased out under the Montreal Protocol. As a result, the abundance of ODSs in the atmosphere has declined and the ozone layer is expected to recover. CFCs also had higher Global Warming Potentials (GWPs) than the HFCs replacing them. As such, by replacing CFCs by HFCs, the refrigeration and air-conditioning industry and other users not only contributed to the preservation of the ozone layer, but also made a most significant and positive contribution to reducing greenhouse gas emissions. Their reduction would represent about four times the objective of the Kyoto Protocol. In 1990, CFCs represented 25 per cent of global greenhouse gas emissions. In 2002, the emissions from the use of HFCs were about 0.5 % of total global GHG emissions and according to the US NOAA (National Oceanic and Atmospheric Administration), which provides annual updates of the AGGI (Annual Greenhouse Gas Index), intended to follow the evolution of the radiative forcing (ability of all greenhouse gases to trap heat) of greenhouse gases, the HFC impact in 2016, was 0.89 % of the total GHG emissions.
The chart below shows the impact on global emissions of switching from ODSs to HFCs. Values are emissions of CFCs, HCFCs and HFCs calculated from globally averaged atmospheric concentrations . In 1990, CFCs represented a significant part of global greenhouse gas emissions. Between, 1990 and 2015, a sharp decline is noted thanks to the replacement by industry.
 The calculation uses the methods described by Rigby & colleagues (2014) with the atmospheric concentrations being measured by AGAGE (https://agage.mit.edu/data/agage-data). Conversion to equivalent tonnes of carbon dioxide used the Global Warming Potentials in IPCC’s Fifth Assessment Report https://www.ipcc.ch/).
The HFCs, low-GWP HFCs, HFC/HFO-blends and HFOs (including HCFOs) have favourable toxicity profiles and provide the required flammability properties necessary for a range of applications. Their safety properties and technical performance enable these fluorocarbons to be used effectively in a wide range of applications.
Where non-flammability is required, some HFCs, HFC/HFO-blends, HFOs and HCFOs are available and have proven technical performance. Non-flammability is an important requirement for many installations used in public places like theatres, supermarkets, transportation and transportation hubs, tall buildings.
For some applications, mildly flammable fluorocarbons (low-GWP HFCs, HFC/HFO-blends and HFOs) can be used and offer excellent technical performance, with lower GWPs compared to non-flammable HFCs.
Refrigerants are classified for toxicity and flammability by standards ASHRAE 34 and EN378, and these properties are used by EN378 to set out use requirements and restrictions for refrigeration, air-conditioning and heat-pump applications. For flammable refrigerants, the safety classification and lower flammability limit (LFL) are factors taken into account when determining refrigerant charge and allowable applications. In particular, ‘mildly flammable’ refrigerants (A2L classification) have different calculations for maximum refrigerant charge when compared to other flammable refrigerants. The tables show the safety classifications and some examples of refrigerants and their safety classification. For a complete list of refrigerant safety classifications see Refrigerants subject to the F-Gas Regulation 517/2014.
Highly flammable (hydrocarbons) and toxic (ammonia) refrigerants, due to their safety profiles, have more constraints on charge size and applications. This is because the consequences of a loss of containment due to a leak or during servicing and maintenance can be severe, particularly for larger refrigerant quantities. Unfortunately, there are have been a number of incidents resulting in injury or death, or considerable damage to property due to such loss of containment.
For other applications such as technical aerosol propellants and solvents, for storage and transportation of bulk fluorocarbon, and handling and use, other standards and requirements apply. The refrigerant safety classification is only used in reference to refrigeration, air conditioning and heat pump system safety. Transport regulations (ADR) and extended REACH compliant Material Safety Data Sheets do not use EN378 safety classifications. All flammable fluorocarbon refrigerants are classified as an extremely flammable gas. The exception to this is the HFO R-1234ze(E), which GHS classifies as non-flammable (at 20°C). Refrigerant safety classification assesses flammability at higher temperature.
The main climate impact of refrigeration: energy consumption
The recent TEAP Report on Energy Efficiency stated that Refrigeration, Air Conditioning and Heat Pumps (RACHP) are increasing rapidly, and in 2015, they were estimated to consume 17% of electricity worldwide. Over 80% of the global warming impact of RACHP systems is associated with the generation of the electricity to operate the equipment (indirect emissions), with a decreasing proportion coming from the use/release (direct emissions) of high Global Warming Potential (GWP) hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) as their use declines. A decrease in the global warming impact of RACHP can be achieved through increased energy efficiency (EE) combined with a transition to low-GWP refrigerants.
Energy efficiency is a key EU priority, with a target to reduce energy consumption by 20% by 2020. A longer energy efficiency term target of 27% reduction by 2030 was agreed in 2014 by the EU Member States. In many applications, fluorocarbon refrigerants (HFCs, lower GWP HFCs, HFC/HFO blends and HFOs) can contribute to significantly lowering the associated CO2 emissions due to their performance, particularly in hot climatic conditions (compared to CO2).
The range of available fluorocarbons (HFCs, lower GWP-HFCs, HFC/HFO-blends and HFOs) allows the design of “tailor-made” refrigerants for specific application sectors, and to deliver high performance with good safety properties.
The majority of heat pumps use HFCs as refrigerant. Their specific properties make them suitable for an efficient process contributing to energy savings. The safety properties of fluorocarbon refrigerants allow their widespread use in efficient designs. See also infographics on heat pumps.
Also, for refrigeration and air-conditioning, fluorocarbon refrigerants are widely used because of their good thermodynamic properties and their adaptability to various operational conditions. They can be used across a wide range of application temperatures and are carefully selected to optimize system efficiency, from small individual air-conditioning systems to large industrial refrigeration and air-conditioning units (see infographics on cold chain).
Systems using fluorocarbon refrigerants are continuously improving and delivering better energy efficiency. In addition, reduced refrigerant charges or lower GWPs and lower emissions can contribute to reducing their environmental impact. See for example EFCTC newsletter of July/August 2018 for examples of improved energy efficiency. The safety properties of the fluorocarbon refrigerants enable them to be used in a wide range of applications when compared to hydrocarbons.
High performance insulation improves energy efficiency primarily by reducing heat transfer. For building insulation, it reduces heat loss or heat gain which improves occupant comfort and can lower energy costs. For cold and chilled storage and transport, it reduces heat gain and helps maintain good temperature control and reduces energy consumption. In blown insulated foams, it is the entrapped gas and the density and structure of the foam – not the polymer material itself– which determines the insulation performance. The HFOs and HCFOs used as foam blowing agents have low thermal conductivity, an important property for insulation foams. Their thermal conductivities are lower than the HFCs they are replacing. In addition, their very low GWPs mean that any blowing agent emissions that occur during foam blowing process, or for spray foam, during the use phase and at end of life have an extremely small impact on global warming. In fact, the GWPs of these HFOs and HCFOs are less than the main hydrocarbon foam blowing agent (pentanes)
The Global Warming Potentials (GWPs) and atmospheric lifetimes for HFCs and HFOs are listed in the table for Fluorocarbons Substances and main applications. The HFCs all have atmospheric lifetimes measured in years, and these lifetimes together with their fluorine content results in higher GWPs. The lifetimes and GWPs tend to be longer for HFCs with higher fluorine content, as this increases stability and infra-red absorption. For the main HFCs, the shortest atmospheric lifetime is 1.5 years for HFC-152a which has a low fluorine content and low GWP (124, F-Gas AR4; 138, AR5). The longest atmospheric lifetime is 222 years for HFC-23, which has a high fluorine content and a very high GWP (14800, F-Gas AR4; 12400, AR5). HFC-32 has a relatively short atmospheric lifetime (5.2 years) and lower GWP (675, F-Gas AR4; 677, AR5).
The HFOs (and HCFOs, HBFOs) all have atmospheric lifetimes measured in days, due to the presence of a C=C double bond which increases the rate of decomposition in the atmosphere. Even though they have similar fluorine content to the HFCs, their short atmospheric lifetimes result in very low GWPs (all <10, AR5 values). The AR5 GWPs for some HFOs, HCFOs, and HBFOs are similar that for CO2 and less than the GWPs of a range of hydrocarbons (propane, butane, isobutane and propylene; GWPs reported as 2-4). In addition, the short atmospheric lifetimes mean that HFOs do not accumulate in the atmosphere.
The HCFOs, R-1233zd(E) and R-1224yd(Z) and the HBFO-1233xfB contain one chlorine atom or one bromine atom, which means they could have an ODP if they are transported to the stratosphere. However, these substances are oxidised rapidly in the lower atmosphere with atmospheric lifetimes measured in days; hence all are very short-lived substances (VSLS)  that, in view of their minimal effect on stratospheric ozone, are not listed as Ozone Depleting Substances in the Montreal Protocol. It takes several months for a substance released in northern temperate regions of the world to be transported through the lower atmosphere before it is injected into the stratosphere. Consequently, very little of these halopropenes can be transported to the ozone layer. In the case of HCFO-1233zd(E), for material emitted between 30o and 60oN, an average Ozone Depletion Potential (ODP) has been calculated to be 0.00034  and, on the same basis, that of HBFO-1233xf(B) is 0.0028 . The ODP of HCFO- 1224yd(Z) is reported as 0.000121 . See Learn about HCFO-1233zdE, HBFO-1233xfB, Stratospheric Ozone and Climate Change.
 Ko M.K.W. and 32 others, Very Short-Lived Halogen and Sulphur Substances, Chapter 2 of Scientific Assessment of Ozone Depletion: 2002, Global Ozone Research and Monitoring Project – Report No. 47, World Meteorological Organization, Geneva, 2002.
 Patten, K. O. and Wuebbles, D. J.: Atmospheric lifetimes and Ozone Depletion Potentials of trans-1-
chloro-3,3,3-trifluoropropylene and trans-1,2-dichloroethylene in a three-dimensional model, Atmos. Chem.
Phys., 10, 10867-10874, https://doi.org/10.5194/acp-10-10867-2010, 2010.
 Patten, K. O., V. G. Khamaganov, V. L. Orkin, S. L. Baughcum, and D. J. Wuebbles (2012), Correction to “OH reaction rate constant, IR absorption spectrum, ozone depletion potentials and global warming potentials of 2-bromo-3,3,3-trifluoropropene,” J. Geophys. Res., 117, D22301, doi:10.1029/2012JD019051.
 Measured by the National Institute of Advanced Industrial Science and Technology, Japan (AIST); GWP calculated according to the IPCC AR5 method.
TFA (trifluoroacetic acid or acetate) is a naturally occurring substance, which is stable in the environment and resistant to further degradation (breakdown). Over 200 million tonnes are present in the oceans and more than 95% of TFA found in the oceans is naturally produced. There is a natural transport cycle for TFA which is shown in the TFA infographic. TFA (trifluoroacetic acid or acetate) is the terminal atmospheric breakdown product in varying yields for some HFCs (HFC-125, HFC-134a, HFC 143a, and HFC-227ea), and some HFOs and HCFOs.
See Learn about Trifluoroacetic Acid and Hydrofluorocarbons (HFCs) or Hydrofluoro-olefins (HFOs) for a summary of the work done by the Environmental Effects Panel of the Montreal Protocol in establishing the environmental context of trifluoroacetic acid (TFA).
The presentation of the Report of the Environmental Effects Assessment Panel at the 2018 30th Meeting of the Parties to the Montreal Protocol stated that “Our previous assessments reported that future concentrations of TFA due to the expected use of ODS replacements do not pose a significant threat to human health or the environment. That assessment remains unchanged.”
Some, but not all HFCs, HFOs and HCFOs containing the CF3-C group can breakdown to TFA in the atmosphere. In reality TFA (trifluoroacetic acid or acetate) is not a significant terminal degradation product of HFC-125 and HFC-143a. The yield of TFA can vary depending on how many breakdown pathways there are . The yield of TFA from HFC-134a is about 20%, and from HFC-227ea is 100% . TFA is a breakdown product of only some HFOs and HCFOs and the TFA yield depends on the atmospheric breakdown pathways [3- 6]. Some examples are shown in the table. The TFA yields have been determined using models and laboratory experiments; for example, no TFA formation could be established for HCFO-1233zd(E) in laboratory experiments. This approach has been used for many years to investigate the breakdown pathways and products of substances in the atmosphere.
 see IPCC/TEAP Special Report: Safeguarding the Ozone Layer and the Global Climate System, 2005 Chapter 2
In the EU, emissions of HFCs were 1.0% of the total greenhouse gas emissions in 1995. The use of HFCs, most prominently in refrigeration and air conditioning, has been increasing, in particular as a replacement for ODS globally phased out under the Montreal Protocol. F-gases, mostly HFCs (more than 90 %), accounted for approximately 3% of overall greenhouse gas emissions expressed as CO2e in the EU in 2015 (‘EEA greenhouse gas data viewer‘). According to the EEA Report Fluorinated greenhouse gases in 2017, 2015 was the first year of declining EU F-gases emissions (4 %) in 15 years. This growth in emissions of HFCs from 1995 was offset to some extent by the steps taken by chemical manufacturers to reduce by-product HFC-23 emissions.
In recent years, the growth in HFC emissions has slowed in the EU (See EFCTC ‘Learn about … The contribution of HFCs to European Greenhouse Gas emissions’), a probable consequence of the controls under the 2006 and 2014 F Gas legislations. The most recent one, Regulation 517/2014, gradually reduces the quantities of hydrofluorocarbons that can be placed on the market, an effective and efficient way of reducing emissions of HFCs. In addition, there are use bans with end dates for applications when it is expected that low GWP solutions should be readily available. These include use bans for some refrigeration, air-conditioning and foam applications. Also, measures require containment during servicing, maintenance and at end-of-life. The F-Gas Regulation thus aims at further reducing F-Gas emissions to reach the targeted decrease of approximately 70 Mt of CO2 equivalent by 2030.
The Kigali Amendment to the Montreal Protocol requires a phase-down of HFCs based on CO2e (CO2 equivalents) similar to that of the F-Gas Regulation. A report issued by the International Panel on Climate Change (IPCC) in April 2005 stated that whilst atmospheric concentrations of HFCs were rising, their contribution to climate change, measured as direct radiative forcing was expected only to be about 1% by 2015, whilst their adoption has contributed to a threefold reduction in the global warming emissions of all halocarbons. The US NOAA (National Oceanic and Atmospheric Administration) provides annual updates of the AGGI (Annual Greenhouse Gas Index), intended to follow the evolution of the radiative forcing (ability of all greenhouse gases to trap heat) of greenhouse gases. The HFC impact in 2016, was 0.89 % of the total, which is lower than that forecast in the 2005 IPCC report. The contribution of HFCs is unlikely to be significantly higher in the future following the adoption of the Kigali Amendment to the Montreal Protocol, requiring an international HFC phase-down.
Furthermore, the records show that emissions of HFCs from developed countries have slowed in recent years [1,2] More detailed information can be found in the ‘Learn about … The Role of HFCs in Long Term Climate Change’.
When it comes to predicted future HFC emissions, some publications speculated about a runaway greenhouse effect due to the replacement of CFCs and HCFCs by HFCs. The F-Gas Regulation and the Kigali Amendment will ensure that use and emissions of HFCs (as CO2e) are reduced.
A global prediction forms part of the Fifth Assessment Report of Working Group I of the Intergovernmental Panel on Climate Change. The Panel evaluated the climate change impact from the anticipated release of greenhouse gases 
For all greenhouse gases, the IPCC authors used Representative Concentration Pathways (RCPs), and one of these (RCP 4.5) is shown in the chart. This scenario envisages rigorous controls on greenhouse gases (particularly CO2 and methane) to limit global temperature rise to about 2.5°C.
The chart below clearly shows that, far from having a runaway climate impact, the effect of the F-Gases will remain constant or will decline over the coming century, both in absolute terms and relative to the other greenhouse gases. For more detail, please click here.
 National Inventories of Greenhouse Gases submitted to the United Nations Framework Convention on Climate Change (www.unfccc.int)
 European Environment Agency Technical Reports for Fluorinated greenhouse gases for example No 15/2013 and 15/2014 (www.eea.europa.eu)
 Climate Change 2013, the Physical Science Basis, Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (http://www.climatechange2013.org/images/report/WG1AR5_ALL_FINAL.pdf)
The Kigali Amendment to the Montreal Protocol and the F-Gas Regulation require a phase-down of HFCs based on CO2e (CO2 equivalents), These measures were introduced to ensure that emissions of HFCs do not increase significantly in the future. When CFCs and HCFCs were phased-out a range of technologies including HFCs were used to replace them. Similarly, the phase-down of HFCs will result in various technologies being used to enable their phase-down. The EU F-Gas Regulation 517/2014 is already leading to a move to lower GWP refrigerants including lower GWP HFCs (such as HFC-32), HFC/HFO-blends and HFOs (and HCFOs), which can offer similar technical and safety properties to HFCs. HFCs continue to have an important role to play, when used responsibly in energy efficient, cost effective, applications. However, a continued focus on containment and recovery at end-of-life is necessary to minimise HFC emissions.
Compared to the HFCs they are replacing, HFC-32 has a GWP about one third of that for R-410A, HFC/HFOs-blends have a range of GWPs depending on the safety (non-flammability or L2 mildly flammable) and performance requirements, but have significantly lower GWPs, and HFOs (including HCFOs) have GWPs <10 or <2 (AR5 GWP values), in a similar range to CO2 and and hydrocarbons. These fluorocarbons are enabling the phase-down of HFCs.
The lower GWP fluorocarbon refrigerants are enabling industry to continue to have access to the technical and safety benefits of fluorocarbon. To maintain good availability the average GWP of the fluorocarbon refrigerants placed on the market must be reduced. This trend is already occurring in the EU.
The average GWP of HFCs and HFOs placed on the EU market has decreased by about 23% since the phase-out of HCFCs at the end 2009 and has fallen every year since then, with a steeper decline following the 2014 F-Gas Regulation.
Data sources for chart
HCFC data in ODP tonnes (assumes all HCFC-22) https://www.unenvironment.org/ozonaction/
HFC/HFO data EEA Report No 20/2017, Fluorinated greenhouse gases in 2017
EFCTC supports and encourages the responsible use of all HFCs and HFC-HFO-blends to minimise emissions, which contribute to global warming. This requires a range of actions by all those involved in the production supply and use of HFCs. The reduction in the emissions of HFCs contributes to the EUs objective to reduce all greenhouse gas emissions. HFOs have extremely low GWPs and their emissions will have an extremely small contribution to global warming. Even so they should be used responsibly to minimise emissions and to ensure resource efficiency.
The EU target for fluorinated greenhouse gases (HFCs, PFCs and SF6) is by 2030 to cut their emissions by two-thirds compared with 2014 levels, with a cumulative reduction in emissions of 5 Gigatonnes CO2-equivalent by 2050.
The responsible use of HFCs is now underpinned and enforced by a range of measures including:
• The F-Gas Regulation 517/2014 on fluorinated greenhouse gases,
• Directive 2006/40/EC of the European Parliament and of the Council of 17 May 2006 relating to emissions from air-conditioning systems in motor vehicles and amending Council Directive 70/156/EEC,
• Directive 2012/19/EU of the European Parliament and of the Council of 4 July 2012 on waste electrical and electronic equipment (WEEE) – recast,
• Directive 2000/53/EC of the European Parliament and of the Council of 18 September 2000 on End-Of Life Vehicles,
This legislation ensures the responsible use of HFCs through measures to minimise leakage, ensure recovery during servicing and maintenance and at end-of-life, implement certain use and placing on the market bans and provide for a phase-down of HFCs that can be used in the EU, encouraging the use of lower GWP fluorocarbons, including lower GWP HFCs, HFC/HFO-blends and HFOs. In addition, the Framework Directive for Ecodesign requirements for energy using products (EuP) has resulted in bonus schemes based on the Global Warming Potential (GWP) of refrigerants.