According to the two main producers – China and India – the release of the potent greenhouse gas HFC-23 into the atmosphere should have almost completely stopped by 2017. However, the reality is that a team of atmospheric researchers led by the University of Bristol has measured record levels. Dr Kieran Stanley, lead author of the study published in the current issue of “Nature Communications”, has been working at Goethe University for six months.
Over the past two decades, researchers have monitored the concentration of the hydrofluorocarbon HFC-23 very closely. “It is a very potent greenhouse gas: The emission of one tonne of this substance does just as much damage as the emission of 12,000 tonnes of carbon dioxide,” says atmospheric researcher Professor Andreas Engel from Goethe University. HFC-23 primarily occurs as an unwanted by-product in the manufacture of the refrigerant HCFC-22.
In 2015 India and China, which are considered the main emitters, announced ambitious plans to abate their factory emissions and in 2017 they reported that almost no more HFC-23 was being vented to the atmosphere. This would mean that emissions of this greenhouse gas into the atmosphere between 2015 and 2017 ought to have shown a 90 percent reduction. However, as the international team now reports, emissions have risen further and in 2018 reached an all-time high.
The reduction of HFCs is part of the Kigali Amendment to the Montreal Protocol agreed in 2016. It entered into force in January 2020. Although China and India have not ratified the Amendment, by their own account they had achieved a massive reduction in emissions. “Our study indicates that China has not managed to reduce HFC-23 as reported,” concludes Dr Kieran Stanley, who conducted the measurements at the University of Bristol in the framework of the international AGAGE measurement network. Additional measurements will show whether India has successfully implemented its abatement programme.
“This is not the first time there’s been controversy about HFC-23 emissions,” says Kieran Stanley ruefully. With the United Nations Framework Convention on Climate Change, between 2005 and 2010 the industrial nations created incentives for emerging countries to reduce their emissions. Although emissions of this hazardous greenhouse gas did indeed decrease during that period, the system backfired: Manufacturers did not optimize their processes but instead produced more harmful by-products in order to pocket more funds for destroying them.
The Institute for Atmospheric and Environmental Sciences at Goethe University, where Kieran Stanley is now working as a postdoctoral researcher, has measured a large number of halogenated trace gases at its Kleiner Feldberg measuring station at regular intervals since 2013. Since recently, these measurements are part of the AGAGE network.
Publication: K. Stanley, D. Say, J. Mühle, C. Harth, P. Krummel, D. Young, S. O’Doherty, P. Salameh, P. Simmonds, R. Weiss, R. Prinn, P. Fraser and M. Rigby: Increase in global emissions of HFC-23 despite near-total expected reductions, in Nature Communications, https://doi.org/10.1038/s41467-019-13899-4