Effective realization of abatement measures can reduce HFC-23 emissions.

HFC-23 is a potent greenhouse gas, predominantly emitted as an undesired by-product during the synthesis and processing of HCFC-22 (ref.  1 ). Previously, the Clean Development Mechanism and national efforts called for the implementation of abatement technology for reducing HFC-23 emissions 2,3 . Nevertheless, between 2015 and 2019, a divergence was found between the global emissions derived from atmospheric observations and those expected from reported abatement 1,2 . Primarily, this points to insufficient implementation of abatement strategies 2,4 , calling for independent verification of the emissions at the individual chemical facility level. Here we use regional atmospheric observations and a new, deliberately released tracer to quantify the HFC-23 emissions from an HCFC-22 and fluoropolymer production facility, which is equipped with waste gas destruction technology. We find that our inferred HFC-23/HCFC-22 emission factor of 0.19% (0.13-0.24%) broadly fits within the emission factor considered practicable for abatement projects 5,6 . Extrapolation to global HCFC-22 production underscores that the operation of appropriate destruction technology has the potential to reduce global HFC-23 emissions by at least 84% (69-100%) (14 (12-16) Gg yr -1 ). This reduction is equivalent to 17% CO 2 emissions from aviation in 2019 (ref.  7 ). We also demonstrate co-destruction of PFC-318, another by-product and greenhouse gas. Our findings show the importance of the 2016 Kigali Amendment to the Montreal Protocol, which obligates parties to destroy HFC-23 emissions from facilities manufacturing hydrochlorofluorocarbons and hydrofluorocarbons "to the extent practicable" from 2020 onwards 8 .