Synthetic greenhouse gases
For key facts and information at a glance, please read our synthetic greenhouse gases factsheet.
What are synthetic greenhouse gases?
Synthetic greenhouse gases are artificial chemicals commonly used in refrigeration and air conditioning, fire extinguishing, foam production and in medical aerosols. They were introduced as replacements for ozone depleting substances as they do not damage the ozone layer. However, synthetic greenhouse gases generally have high global warming potential; when they are released, they trap heat in the atmosphere. Because of their stability and long life they can remain in the atmosphere for a long time, increasing their contribution to climate change.
How are they different to ‘greenhouse gases’?
Greenhouse gases include carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Most greenhouse gases are naturally occurring, but are also emitted as a result of industrial processes and other human activity. Synthetic greenhouse gases are man-made chemicals that do not occur in nature and generally have a much higher global warming potential than other greenhouse gases.
What is global warming potential?
Global warming potential (GWP) is a measure of how much heat a greenhouse gas traps in the atmosphere over a specific time compared to a similar mass of carbon dioxide (CO2). Carbon dioxide, with a global warming potential of 1, is used as the base figure for measuring global warming potential. The higher the number, the more heat a gas traps. The most common synthetic greenhouse gas in Australia is HFC-134a, which is mostly used in refrigerators and air conditioners. It has a global warming potential of 1430; this means the release of one tonne of HFC-134a is equivalent to releasing 1430 tonnes of CO2 into the atmosphere.
Other synthetic greenhouse gases are even more powerful global warmers, with perfluorocarbons (PFCs) having global warming potentials between 6500-9200 and sulfur hexafluoride (SF6) having a global warming potential of 22,800.
The first synthetic greenhouse gases developed had high global warming potential. These are gradually being replaced by new synthetic greenhouse gases with lower global warming potentials.
Did you know: Synthetic greenhouse gases account for around 2 per cent of all greenhouse gas emissions in Australia.
Which gases does Australia regulate?
The Australian Government is committed to reducing Australia’s emissions of the synthetic greenhouse gases listed under the United Nations Framework Convention on Climate Change and the Kyoto Protocol. All four synthetic greenhouse gases listed in the Kyoto Protocol are regulated in Australia under the Ozone Protection and Synthetic Greenhouse Gas Management Act 1989:
- hydrofluorocarbons (HFCs)
- perfluorocarbons (PFCs)
- sulfur hexafluoride (SF6)
- nitrogen trifluoride (NF3).
How do we use them?
Synthetic greenhouse gases are man-made chemicals and are used in Australia for a wide variety of purposes. They are most commonly used as:
- refrigerant in air conditioning and refrigeration equipment
- extinguishing agents in fire extinguishing systems
- foam-blowing agents in the manufacture of polyurethane foams and in foams for thermal insulation, such as in refrigerators
- propellants in some aerosol products
- insulating gas in the electricity supply industry
- solvents
How do emissions occur?
Synthetic greenhouse gas emissions occur mainly through leakage such as from pieces of refrigeration and air conditioning equipment, their intended use in an aerosol or fire extinguisher, or as a by-product of industrial activity such as aluminium smelting. The main sources of synthetic greenhouse gas emissions include:
- HFCs (and sometimes PFCs) are used as refrigerants in industrial, commercial and domestic refrigeration and air conditioning equipment. Emissions occur due to leakage from piping, joints and seals and during the maintenance and decommissioning of equipment.
- HFCs are used as foam-blowing agents in the manufacture of polyurethane foams and foams for thermal insulation. The synthetic greenhouse gas is released at the time the foam is blown and will gradually leak into the atmosphere during the lifetime of the foam.
- HFCs are used as propellants in aerosols (mainly in metered dose inhalers such as asthma puffers) and in products requiring a non-flammable propellant for reasons of safety.
- HFCs (and to a lesser extent PFCs) are used as fire extinguishing agents in some hand held fire extinguishers and some fixed flooding systems.
- The aluminium industry is the main source of Australia's PFCs emissions, which are produced as a by-product during the electrolytic smelting process which creates aluminium from its ore, and
- Sulfur hexafluoride (SF6) is used as an insulating gas by the electricity supply industry to prevent arcing in electrical switchgear. Emissions occur due to leakage and during equipment maintenance and decommissioning.
- Nitrogen trifluoride (NF3) is used in Australia to manufacture semi-conductors. It is mainly converted to a benign substance during the manufacturing process.