Changing trends and emissions of hydrochlorofluorocarbons and their hydrofluorocarbon replacements
18 High frequency, in situ global observations of HCFC 22 (CHClF2) HCFC 141b (CH3CCl2F) 19 HCFC 142b (CH3CClF2) and HCFC 124 (CHClFCF3) and their main HFC replacements HFC 134a 20 (CH2FCF3) HFC 125 (CHF2CF3) HFC 143a (CH3CF3) and HFC 32 (CH2F2) have been used to 21 determine their changing global growth rates and emissions in response to the Montreal Protocol and its 22 recent amendments. The 2007 adjustment to the Montreal Protocol required the accelerated phase out of 23 HCFCs with global production and consumption capped in 2013, to mitigate their environmental impact 24 as both ozone depleting substances and important greenhouse gases. We find that this change has 25 coincided with a reduction in global emissions of the four HCFCs with aggregated global emissions in 26 2015 of 444 75 Gg/yr, in CO2 equivalent units (CO2 e) 0.75 0.1 Gt/yr, compared with 483 70 Gg/yr 27 (0.82 0.1 Gt/yr CO2 e) in 2010. (All quoted uncertainties in this paper are 1 sigma) About 80% of the 28 total HCFC atmospheric burden in 2015 is HCFC 22, where global HCFC emissions appear to have been 29 relatively constant in spite of the 2013 cap on global production and consumption. We attribute this to a 30 probable increase in production and consumption of HCFC 22 in Montreal Protocol Article 5 31 (developing) countries and the continuing release of HCFC 22 from the large banks which dominate 32 HCFC global emissions. Conversely, the four HFCs all show increasing annual growth rates with 33 aggregated global HFCs emissions in 2015 of 329 70 Gg/yr (0.65 0.12 Gt/yr CO2 e) compared to 34 2010 with 240 50 Gg/yr (0.47 0.08 Gt/yr CO2 e) As HCFCs are replaced by HFCs we investigate the 35 impact of the shift to refrigerant blends which have lower global warming potentials (GWPs) We also 36 Atmos. Chem. Phys. Discuss. doi:10.5194/acp 2016 977, 2016 Manuscript under review for journal Atmos. Chem. Phys. Published: 15 December 2016 c (c) Author(s) 2016. CC BY 3.0 License.