HFC phase out

Hydrofluorocarbons (HFCs) are a group of gases used as refrigerants, blowing agents and aerosol propellants. They became popular following the phasing out of CFCs (chlorofluorocarbons) and then HCFCs (hydrochlorofluorocarbons), both of which were significant greenhouse gases.

Greenhouse gases are relatively transparent to short-wave infrared radiation. This means they allow sunlight to enter the atmosphere and heat the Earth’s surfaces. These surfaces then re-radiate that heat as long-wave infrared radiation, which greenhouse gases tend to absorb rather than transmit. As a result, heat accumulates in the atmosphere causing a warming process known as the greenhouse effect.

The four main greenhouse gases are:

• Water vapour.
• Carbon dioxide.
• Methane.
• Nitrous oxide.

However, HFCs are also greenhouse gases, albeit not as powerful as CFCs or HCFCs. Demand for HFCs has increased rapidly following the phasing out of CFCs and HCFCs and this has been exacerbated by the growth of air conditioning in developing nations. As a result, on 15 October 2016 it was announced that 170 countries in Kigali, Rwanda, had agreed that HFCs should be phased down through an amendment to the Montreal Protocol.

The agreement has three main routes for phasing down HFCs:

• Richer countries will reduce use by at least 10% compared to 2011-2013 levels by 2019 and then by 85% by 2036.
• Better-off developing countries will freeze their use from 2024, then reduce use by 10% compared to 2020-2022 levels by 2029, and then by 80% by 2045.
• Other developing countries will freeze their use from 2028, reduce use by 10% by 2032 compared to 2024-2026 levels, and then by 85% by 2047.

US Secretary of State John Kerry said, "It's a monumental step forward, that addresses the needs of individual nations but it will give us the opportunity to reduce the warming of the planet by an entire half a degree centigrade."

Christian Aid's Senior Policy Advisor, Benson Ireri said, "HFCs posed an immediate threat to a safe climate due to their increasing use and high global warming potential, thousands of times more potent than carbon dioxide. By agreeing to an early HFC phase down schedule, we've bought ourselves a bit more time to shift to a global low carbon economy and protect the world's most vulnerable people."

But environmental lobby groups were critical of the agreement, suggesting that it did not go far enough or fast enough. Paula Tejon Carbajal from Greenpeace International said, "It's an incremental step towards 0.5 degrees but its not there yet, they say that the market will work to get us there, but we are not there yet."

Alternative refrigerants to HFCs include; hydrocarbons (HC), Hydrofluoroolefin (HFO) carbon dioxide, and ammonia (as well as air and water).

However, Greenpeace suggest while HFOs have lower global warming potential (GWP) than HFCs they nonetheless pose dangers to the environment.

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