CSIRO data used to prove HFC-23 greenhouse gas on the rise

CSIRO has contributed to an international study on rising levels of hydroflourocarbon-23 (HFC-23), a greenhouse gas that is 12,400 times more potent than carbon dioxide in the atmosphere.

HFC-23 is an unwanted by-product of chlorodifluoromethane (HCFC-22) production; HCFC-22 is used largely in air conditioning equipment. Because of its role in ozone layer depletion, HCFC-22 was phased out in the late 1990s.

Under the Montreal Protocol and its Clean Development Mechanism, HCFC-22 production processes were modified such that HFC-23 emissions should have dropped by nearly 90% between 2014 and 2017 if voluntarily adopted by developing countries. However, atmospheric observations, which included CSIRO’s Cape Grim air archive and Antarctic firn air data showed that HFC-23 emissions have instead increased, and reached a peak level in 2018.

CSIRO atmospheric researcher Paul Fraser, who has conducted research on CFCs for over 40 years, said that the research paper was a global study with implications for developing countries such as India and China, whose phase-out programs for HCFCs, as allowed under the Protocol, trailed 10-15 years behind developed countries including Australia.

“Air conditioning and refrigeration systems have relatively long shelf lives of approximately 10 years,” said Paul.

“Transitioning to less polluting technologies remains a challenge for citizens in developing countries,  both in implementing national programs to reduce greenhouse gas emissions, and producing and adopting improved technologies.”

“The good news is that we expect a positive response from developing countries and HFC-23 levels to stop growing in the atmosphere in the next decade.”

The findings, which were led by the University of Bristol, were published in Nature Communications last week.