Changing trends and emissions of hydrochlorofluorocarbons and their
Peter G. Simmonds1, Matthew Rigby1, Archibold McCulloch1, Simon O'Doherty1, Dickon Young1, Jens Mühle2, Paul B. Krummel3, L. Paul Steele3, Paul J. Fraser3, Alistair J. Manning4, Ray F. Weiss2, Peter K. Salameh2, Chris M. Harth2, Ray H. J. Wang5, and Ronald G. Prinn61Atmospheric Chemistry Research Group, University of Bristol, Bristol, BS8 1TS, UK 2Scripps Institution of Oceanography (SIO), University of California, San Diego, La Jolla, California, USA 3CSIRO Oceans and Atmosphere, Aspendale, Victoria 3195, Australia 4Met Office Hadley Centre, Exeter, EX1 3PB, UK 5School of Earth, and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA 6Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
Received: 03 Nov 2016 – Accepted for review: 06 Dec 2016 – Discussion started: 15 Dec 2016
Abstract. High frequency, in situ global observations of HCFC-22 (CHClF2), HCFC-141b (CH3CCl2F), HCFC-142b (CH3CClF2) and HCFC-124 (CHClFCF3) and their main HFC replacements HFC-134a (CH2FCF3), HFC-125 (CHF2CF3), HFC-143a (CH3CF3), and HFC-32 (CH2F2) have been used to determine their changing global growth rates and emissions in response to the Montreal Protocol and its recent amendments. The 2007 adjustment to the Montreal Protocol required the accelerated phase-out of HCFCs with global production and consumption capped in 2013, to mitigate their environmental impact as both ozone depleting substances and important greenhouse gases. We find that this change has coincided with a reduction in global emissions of the four HCFCs with aggregated global emissions in 2015 of 444 ± 75 Gg/yr, in CO2 equivalent units (CO2 e) 0.75 ± 0.1 Gt/yr, compared with 483 ± 70 Gg/yr (0.82 ± 0.1 Gt/yr CO2 e) in 2010. (All quoted uncertainties in this paper are 1 sigma). About 80 % of the total HCFC atmospheric burden in 2015 is HCFC-22, where global HCFC emissions appear to have been relatively constant in spite of the 2013 cap on global production and consumption. We attribute this to a probable increase in production and consumption of HCFC-22 in Montreal Protocol Article 5 (developing) countries and the continuing release of HCFC-22 from the large banks which dominate HCFC global emissions. Conversely, the four HFCs all show increasing annual growth rates with aggregated global HFCs emissions in 2015 of 329 ± 70 Gg/yr (0.65 ± 0.12 Gt/yr CO2 e) compared to 2010 with 240 ± 50 Gg/yr (0.47 ± 0.08 Gt/yr CO2 e). As HCFCs are replaced by HFCs we investigate the impact of the shift to refrigerant blends which have lower global warming potentials (GWPs). We also note that emissions of HFC-125 and HFC-32 appear to have increased more rapidly during the 2011–2015 5-yr period compared to 2006–2010.
Simmonds, P. G., Rigby, M., McCulloch, A., O'Doherty, S., Young, D., Mühle, J., Krummel, P. B., Steele, L. P., Fraser, P. J., Manning, A. J., Weiss, R. F., Salameh, P. K., Harth, C. M., Wang, R. H. J., and Prinn, R. G.: Changing trends and emissions of hydrochlorofluorocarbons and their
hydrofluorocarbon replacements, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-977, in review, 2016.