|Title||Increase in global emissions of HFC-23 despite near-total expected reductions|
|Publication Type||Journal Article|
|Year of Publication||2020|
|Authors||Stanley K.M, Say D., Mühle J, Harth CM, Krummel PB, Young D, O'Doherty S.J, Salameh PK, Simmonds PG, Weiss RF, Prinn RG, Fraser PJ, Rigby M|
|Type of Article||Article|
|Keywords||chf3; gases; growth; halocarbons; history; Science & Technology - Other Topics|
Under the Kigali Amendment to the Montreal Protocol, new controls are being implemented to reduce emissions of HFC-23 (CHF3), a by-product during the manufacture of HCFC-22 (CHClF2). Starting in 2015, China and India, who dominate global HCFC-22 production (75% in 2017), set out ambitious programs to reduce HFC-23 emissions. Here, we estimate that these measures should have seen global emissions drop by 87% between 2014 and 2017. Instead, atmospheric observations show that emissions have increased and in 2018 were higher than at any point in history (15.9 +/- 0.9 Gg yr(-1)). Given the magnitude of the discrepancy between expected and observation-inferred emissions, it is likely that the reported reductions have not fully materialized or there may be substantial unreported production of HCFC-22, resulting in unaccounted-for HFC-23 by-product emissions. The difference between reported and observation-inferred estimates suggests that an additional similar to 309 Tg CO2-equivalent emissions were added to the atmosphere between 2015 and 2017.