There is a dark irony in using air conditioners to combat rising temperatures when those very systems are contributors to global warming. So, too, are refrigerators, aerosols and foams. All emit hydrofluorocarbons (HFCs), gases that, like methane, linger in the atmosphere for a relatively short time (15 years) but trap up to 11,700 times as much heat as CO², according to the USA’s Environmental Protection Agency.
HFCs have done the job of ozone-damaging CFCs since those were outlawed by the 1987 Montreal Protocol on Substances that deplete the Ozone Layer. As scientists have realised that the substitute may not pose a threat to the ozone layer but is damaging in different ways, governments have agreed that efforts should be made to reduce emissions from HFCs also.
The 28th meeting of the Parties to the Montreal Protocol has been held this week in Kigali, the capital of Rwanda, whose aim is to agree a target on HFC emissions reduction before the close of play today. It is a feather in Rwanda’s cap to host such a significant gathering of the world’s sustainability elite: around three quarters of the signatory nations to the original protocol are in attendance including Secretary of State John Kerry who took time out from brokering a ceasefire in Yemen to fly in yesterday evening.
Africa, like the USA, is keen to enforce national obligations to cut HFC emissions at the earliest possible date but manufacturing nations with significant output of the gases are arguing for a longer preparation period. China would prefer to defer until 2022 the ‘baseline’ point after which emissions must decline and India is talking about 2024.
Scientists argue that 100-200 billion tonnes of CO² equivalent emissions could be avoided by adhering to a 2020 deadline, slowing the rate of rising temperatures by 0.5%. They cite the positive effects of the Montreal Protocol’s CFC work which achieved a reduction of135 billion tonnes of CO² equivalent emissions and forced manufacturers to design new air conditioning systems resulting in increased efficiency of 60% in some cases.
HFCs, like CFCs, are man-made but there are already refrigerators available that are cooled using natural gases such as ammonia and hydrocarbons.
As the Executive Director of the United Nations Environmental Program, UNEP, said in his opening address:
“No one, frankly, will forgive you if you cannot find a compromise at this conference”
Erik Solheim, executive director of United Nations Environmental Program (UNEP).
 Environmental Protection Agency. Abstract: Modeling emissions of high global warming potential gases. www3.epa.gov
 Economist. Why world leaders are meeting to discuss hydrofluorocarbons. 9 October 2016. www.economist.com
 New York Times. A climate success story to build on. 25 September 2012. www.nytimes.com