Articles | Volume 22, issue 17
Research article
 | Highlight paper
01 Sep 2022
Research article | Highlight paper |  | 01 Sep 2022

Bayesian assessment of chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC) and halon banks suggest large reservoirs still present in old equipment

Megan Jeramaz Lickley, John S. Daniel, Eric L. Fleming, Stefan Reimann, and Susan Solomon

Data sets

History of chemically and radiatively important atmospheric gases from the Advanced Global Atmospheric Gases Experiment (AGAGE) ( R. G. Prinn, R. F. Weiss, J. Arduini, T. Arnold, H. L. DeWitt, P. J. Fraser, A. L. Ganesan, J. Gasore, C. M. Harth, O. Hermansen, J. Kim, P. B. Krummel, S. Li, Z. M. Loh, C. R. Lunder, M. Maione, A. J. Manning, B. R. Miller, B. Mitrevski, J. Mühle, S. O'Doherty, S. Park, S. Reimann, M. Rigby, T. Saito, P. K. Salameh, R. Schmidt, P. G. Simmonds, L. P. Steele, M. K. Vollmer, R. H. Wang, B. Yao, Y. Yokouchi, D. Young, and L. Zhou

2001 database AFEAS

Model code and software

meglickley/HalocarbonBanks: HalocarbonBanks2022 (v1.0) M. Lickley

Executive editor
Banks of ozone-depleting halogenated carbon compounds continue to be sources of emissions. Their contribution to current and future emissions, however, is highly uncertain, and this uncertainty obscures ongoing emissions attribution and undermines international efforts to evaluate global compliance with the Montreal Protocol. The paper by Lickley et al. presents a convincing and thorough method to assess the banks of several halocarbons and their emissions based on known atmospheric lifetimes and constrained by observed atmospheric concentrations. The authors demonstrate that the banks of the halocarbons under assessment are very likely larger than previous international assessments suggest, and that total production has been very likely higher than reported. These are most important results that will find their way in the next WMO ozone assessment and have to be considered in assessments of global warming.
Short summary
Halocarbons contained in equipment continue to be emitted after production has ceased. These banks must be carefully accounted for in evaluating compliance with the Montreal Protocol. We extend a Bayesian model to the suite of regulated chemicals subject to banking. We find that banks are substantially larger than previous estimates, and we identify banks by chemical and equipment type whose future emissions will contribute to global warming and delay ozone-hole recovery if left unrecovered.
Final-revised paper