Abrupt reversal in emissions and atmospheric abundance of HCFC-133a (CF3 CH2 Cl) (original) (raw)
Related papers
A renewed rise in global HCFC-141b emissions between 2017–2021
Atmospheric Chemistry and Physics, 2022
Global emissions of the ozone-depleting gas HCFC-141b (1,1-dichloro-1-fluoroethane, CH 3 CCl 2 F) derived from measurements of atmospheric mole fractions increased between 2017 and 2021 despite a fall in reported production and consumption of HCFC-141b for dispersive uses. HCFC-141b is a controlled substance under the Montreal Protocol, and its phase-out is currently underway, after a peak in reported consumption and production in developing (Article 5) countries in 2013. If reported production and consumption are correct, our study suggests that the 2017-2021 rise is due to an increase in emissions from the bank when appliances containing HCFC-141b reach the end of their life, or from production of HCFC-141b not reported for dispersive uses. Regional emissions have been estimated between 2017-2020 for all regions where measurements have sufficient sensitivity to emissions. This includes the regions of northwestern Europe, east Asia, the United States and Australia, where emissions decreased by a total of 2.3 ± 4.6 Gg yr −1 , compared to a mean global increase of 3.0 ± 1.2 Gg yr −1 over the same period. Collectively these regions only account for around 30 % of global emissions in 2020. We are not able to pinpoint the source regions or specific activities responsible for the recent global emission rise.
Atmospheric Chemistry and Physics, 2018
High frequency measurements of trifluoromethane (HFC-23, CHF 3), a potent hydrofluorocarbon greenhouse gas, largely emitted to the atmosphere as a by-product of the production of the hydrochlorofluorocarbon HCFC-22 (CHClF 2), at five core stations of the Advanced Global Atmospheric Gases Experiment (AGAGE) network, combined with measurements on firn air, old Northern Hemisphere air samples and Cape Grim Air Archive (CGAA) air samples, are used to explore the current and historic changes in the atmospheric abundance of HFC-23. These measurements are used in combination with the AGAGE 2-D atmospheric 12-box model and a Bayesian inversion methodology to determine model atmospheric mole fractions and the history of global HFC-23 emissions. The global modelled annual mole fraction of HFC-23 in the background atmosphere was 28.9 ± 0.6 pmol mol −1 at the end of 2016, representing a 28 % increase from 22.6 ± 0.4 pmol mol −1 in 2009. Over the same time frame, the modelled mole fraction of HCFC-22 increased by 19 % from 199 ± 2 to 237 ± 2 pmol mol −1. However, unlike HFC-23, the annual average HCFC-22 growth rate slowed from 2009 to 2016 at an annual average rate of −0.5 pmol mol −1 yr −2. This slowing atmospheric growth is consistent with HCFC-22 moving from dispersive (high fractional emissions) to feedstock (low fractional emissions) uses, with HFC-23 emissions remaining as a consequence of incomplete mitigation from all HCFC-22 production. Our results demonstrate that, following a minimum in HFC-23 global emissions in 2009 of 9.6 ± 0.6, emissions increased to a maximum in 2014 of 14.5 ± 0.6 Gg yr −1 and then declined to 12.7 ± 0.6 Gg yr −1 (157 Mt CO 2 eq. yr −1) in 2016. The 2009 emissions minimum is consistent with estimates based on national reports and is likely a response to the implementation of the Clean Development Mechanism (CDM) to mitigate HFC-23 emissions by incineration in developing (non-Annex 1) countries under the Kyoto Protocol. Our derived cumulative emissions of HFC-23 during 2010-2016 were 89 ± 2 Gg (1.1 ± 0.2 Gt CO 2 eq.), which led to an increase in radiative forcing of 1.0 ± 0.1 mW m −2 over the same period. Although the CDM had reduced global HFC-23 emissions, it cannot now offset the higher emissions from increasing HCFC-22 production in non-Annex 1 countries, as the CDM was closed to new entrants in 2009. We also find that the cumulative European HFC-23 emissions from 2010 to 2016 were ∼ 1.3 Gg, corresponding to just 1.5 % of Published by Copernicus Publications on behalf of the European Geosciences Union. 4154 P. G. Simmonds et al.: Recent increases in the atmospheric growth rate cumulative global HFC-23 emissions over this same period. The majority of the increase in global HFC-23 emissions since 2010 is attributed to a delay in the adoption of mitigation technologies, predominantly in China and East Asia. However, a reduction in emissions is anticipated, when the Kigali 2016 amendment to the Montreal Protocol, requiring HCFC and HFC production facilities to introduce destruction of HFC-23, is fully implemented.
Atmospheric Chemistry and Physics, 2017
High-frequency, in situ global observations of HCFC-22 (CHClF 2), HCFC-141b (CH 3 CCl 2 F), HCFC-142b (CH 3 CClF 2) and HCFC-124 (CHClFCF 3) and their main HFC replacements, HFC-134a (CH 2 FCF 3), HFC-125 (CHF 2 CF 3), HFC-143a (CH 3 CF 3) and HFC-32 (CH 2 F 2), have been used to determine their changing global growth rates and emissions in response to the Montreal Protocol and its recent amendments. Global mean mole fractions of HCFC-22,-141b, and-142b have increased throughout the observation period, reaching 234, 24.3 and 22.4 pmol mol −1 , respectively, in 2015. HCFC-124 reached a maximum global mean mole fraction of 1.48 pmol mol −1 in 2007 and has since declined by 23 % to 1.14 pmol mol −1 in 2015. The HFCs all show increasing global mean mole fractions. In 2015 the global mean mole fractions (pmol mol −1) were 83.3 (HFC-134a), 18.4 (HFC-125), 17.7 (HFC-143a) and 10.5 (HFC-32). The 2007 adjustment to the Montreal Protocol required the accelerated phase-out of emissive uses 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 stabilisation, or moderate reduction, in global emissions of the four HCFCs with aggregated global emissions in 2015 of 449 ± 75 Gg yr −1 , in CO 2 equivalent units (CO 2 eq.) 0.76 ± 0.1 Gt yr −1 , compared with 483 ± 70 Gg yr −1 (0.82 ± 0.1 Gt yr −1 CO 2 eq.) in 2010 (uncertainties are 1σ throughout this paper). About 79 % of the total HCFC atmospheric burden in 2015 is HCFC-22, where global emissions appear to have been relatively similar since 2011, in spite of the 2013 cap on emissive uses. 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 mole fraction growth rates with aggregated global HFC emissions of 327 ± 70 Gg yr −1 (0.65 ± 0.12 Gt yr −1 CO 2 eq.) in 2015 compared to 240 ± 50 Gg yr −1 (0.47 ± 0.08 Gt yr −1 CO 2 eq.) in 2010. We also note that emissions of HFC-125 and HFC-32 appear to have increased more rapidly averaged over the 5-year period 2011-2015, compared to 2006-2010. As noted by Lunt et al. (2015) this may reflect a change to refrigerant blends, such as R-410A, which contain HFC-32 and-125 as a 50 : 50 blend. Published by Copernicus Publications on behalf of the European Geosciences Union. * Hurwitz et al. (2015) calculated small, non-zero effects on stratospheric ozone due to the influence of these substances on stratospheric temperature (an effect not confined to HFCs). Notes: a ODPs from the Montreal Protocol; b GWPs (100-year) from Forster et al. (2007); c GWPs from Myhre and Shindell (2013); d atmospheric lifetimes, from SPARC (2013).
First observations, trends, and emissions of HCFC-31 (CH 2 ClF) in the global atmosphere
Geophysical Research Letters, 2015
We report the first multiyear atmospheric record of HCFC-31 (CH 2 ClF), based on flask samples and in situ analyses of air from both hemispheres. Although HCFC-31 has never been produced in large amounts, observed mole fractions in the Northern Hemisphere increased from 2000 onward, reaching 170 ppq (parts per quadrillion, 10 À15) in 2011-2012 before decreasing rapidly. By combining our observations with a two-dimensional atmospheric chemistry-transport model, we infer an increase in global emissions from 240 t yr À1 in 2000 to 840 t yr À1 in 2011-2012, followed by a relatively fast decline to 570 t yr À1 in 2014. Emissions of HCFC-31 originate most probably from intermediate product release during the manufacturing process of HFC-32 (CH 2 F 2). The rapid decline in recent years could be due to changes in production methods rather than declines in diffusive sources such as landfills or HCFC-31 contaminations in merchandised HFC-32.
Atmospheric Chemistry and Physics, 2018
Based on observations of the chlorofluorocarbons CFC-13 (chlorotrifluoromethane), CFC-114 (combined measurement of both isomers of dichlorotetrafluoroethane), and CFC-115 (chloropentafluoroethane) in atmospheric and firn samples, we reconstruct records of their tropospheric histories spanning nearly 8 decades. These compounds were measured in polar firn air samples, in ambient air archived in canisters, and in situ at the AGAGE (Advanced Global Atmospheric Gases Experiment) network and affiliated sites. Global emissions to the atmosphere are derived from these observations using an inversion based on a 12-box atmospheric transport model. For CFC-13, we provide the first comprehensive global analysis. This compound increased monotonically from its first appearance in the atmosphere in the late 1950s to a mean global abundance of 3.18 ppt (dry-air mole fraction in parts per trillion, pmol mol −1) in 2016. Its growth rate has decreased since the mid-1980s but has remained at a surprisingly high mean level of 0.02 ppt yr −1 since 2000, resulting in a continuing growth of CFC-13 in the atmosphere. CFC-114 increased from its appearance in the 1950s to a maximum of 16.6 ppt in the early 2000s and has since slightly declined to 16.3 ppt in 2016. CFC-115 increased monotonically from its first appearance in the 1960s and reached a global mean mole frac-Published by Copernicus Publications on behalf of the European Geosciences Union. 980 M. K. Vollmer et al.: Minor CFCs tion of 8.49 ppt in 2016. Growth rates of all three compounds over the past years are significantly larger than would be expected from zero emissions. Under the assumption of unchanging lifetimes and atmospheric transport patterns, we derive global emissions from our measurements, which have remained unexpectedly high in recent years: mean yearly emissions for the last decade (2007-2016) of CFC-13 are at 0.48 ± 0.15 kt yr −1 (> 15 % of past peak emissions), of CFC-114 at 1.90 ± 0.84 kt yr −1 (∼ 10 % of peak emissions), and of CFC-115 at 0.80 ± 0.50 kt yr −1 (> 5 % of peak emissions). Mean yearly emissions of CFC-115 for 2015-2016 are 1.14 ± 0.50 kt yr −1 and have doubled compared to the 2007-2010 minimum. We find CFC-13 emissions from aluminum smelters but if extrapolated to global emissions, they cannot account for the lingering global emissions determined from the atmospheric observations. We find impurities of CFC-115 in the refrigerant HFC-125 (CHF 2 CF 3) but if extrapolated to global emissions, they can neither account for the lingering global CFC-115 emissions determined from the atmospheric observations nor for their recent increases. We also conduct regional inversions for the years 2012-2016 for the northeastern Asian area using observations from the Korean AGAGE site at Gosan and find significant emissions for CFC-114 and CFC-115, suggesting that a large fraction of their global emissions currently occur in northeastern Asia and more specifically on the Chinese mainland.
Increase in HFC-134a emissions in response to the success of the Montreal Protocol
Journal Of Geophysical Research: Atmospheres, 2015
The 1,1,1,2-tetrafluoroethane (HFC-134a), an important alternative to CFC-12 in accordance with the Montreal Protocol on Substances that Deplete the Ozone Layer, is a high global warming potential greenhouse gas. Here we evaluate variations in global and regional HFC-134a emissions and emission trends, from 1995 to 2010, at a relatively high spatial and temporal (3.75°in longitude × 2.5°in latitude and 8 day) resolution, using surface HFC-134a measurements. Our results show a progressive increase of global HFC-134a emissions from 19 ± 2 Gg/yr in 1995 to 167 ± 5 Gg/yr in 2010, with both a slowdown in developed countries and a 20%/yr increase in China since 2005. A seasonal cycle is also seen since 2002, which becomes enhanced over time, with larger values during the boreal summer.
2017
Based on observations of the chlorofluorocarbons CFC-13 (chlorotrifluoromethane), CFC-114 (combined measurement of both isomers of dichlorotetrafluoroethane), and CFC-115 (chloropentafluoroethane) in atmospheric and firn samples, we reconstruct records of their tropospheric histories spanning nearly 8 decades. These compounds were measured in polar firn air samples, in ambient air archived in canisters, and in situ at the AGAGE (Advanced Global Atmospheric Gases Experiment) network and affiliated sites. Global emissions to the atmosphere are derived from these observations using an inversion based on a 12-box atmospheric transport model. For CFC-13, we provide the first comprehensive global analysis. This compound increased monotonically from its first appearance in the atmosphere in the late 1950s to a mean global abundance of 3.18 ppt (dry-air mole fraction in parts per trillion, pmol mol −1) in 2016. Its growth rate has decreased since the mid-1980s but has remained at a surprisingly high mean level of 0.02 ppt yr −1 since 2000, resulting in a continuing growth of CFC-13 in the atmosphere. CFC-114 increased from its appearance in the 1950s to a maximum of 16.6 ppt in the early 2000s and has since slightly declined to 16.3 ppt in 2016. CFC-115 increased monotonically from its first appearance in the 1960s and reached a global mean mole frac-Published by Copernicus Publications on behalf of the European Geosciences Union. 980 M. K. Vollmer et al.: Minor CFCs tion of 8.49 ppt in 2016. Growth rates of all three compounds over the past years are significantly larger than would be expected from zero emissions. Under the assumption of unchanging lifetimes and atmospheric transport patterns, we derive global emissions from our measurements, which have remained unexpectedly high in recent years: mean yearly emissions for the last decade (2007-2016) of CFC-13 are at 0.48 ± 0.15 kt yr −1 (> 15 % of past peak emissions), of CFC-114 at 1.90 ± 0.84 kt yr −1 (∼ 10 % of peak emissions), and of CFC-115 at 0.80 ± 0.50 kt yr −1 (> 5 % of peak emissions). Mean yearly emissions of CFC-115 for 2015-2016 are 1.14 ± 0.50 kt yr −1 and have doubled compared to the 2007-2010 minimum. We find CFC-13 emissions from aluminum smelters but if extrapolated to global emissions, they cannot account for the lingering global emissions determined from the atmospheric observations. We find impurities of CFC-115 in the refrigerant HFC-125 (CHF 2 CF 3) but if extrapolated to global emissions, they can neither account for the lingering global CFC-115 emissions determined from the atmospheric observations nor for their recent increases. We also conduct regional inversions for the years 2012-2016 for the northeastern Asian area using observations from the Korean AGAGE site at Gosan and find significant emissions for CFC-114 and CFC-115, suggesting that a large fraction of their global emissions currently occur in northeastern Asia and more specifically on the Chinese mainland.
Global and regional emissions estimates of HFC-152a
2015
High frequency, ground-based, in situ measurements from eleven globally-distributed sites covering 1994-2014, combined with measurements of archived air samples dating from 1978 onward and atmospheric transport models, have been used to estimate the growth of 1,1-difluoroethane (HFC-152a, CH 3 CHF 2) mole fractions in the atmosphere and the global emissions required to derive the observed growth. HFC-152a is a significant greenhouse gas but since it does not contain chlorine or bromine, HFC-152a makes no direct contribution to the destruction of stratospheric ozone and is therefore used as a substitute for the ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). HFC-152a has exhibited substantial atmospheric growth since the first measurements reaching a maximum annualised global growth rate of 0.81 ± 0.05 ppt yr −1 in 2006, implying a substantial increase in emissions up to 2006. However, since 2007, the annualised rate of growth has slowed to 0.38 ± 0.04 ppt yr −1 in 2010 with a further decline to an average rate of change in 2013-2014 of −0.06 ± 0.05 ppt yr −1. The average Northern Hemisphere (NH) mixing ratio in 1994 was 1.2 ppt rising to a mixing ratio of 10.2 ppt in December 2014. Average annual mixing ratios in the Southern Hemisphere (SH) in 1994 and 2014 were 0.34 and 4.4 ppt, respectively. We estimate global emissions of HFC-152a have risen from 7.3±5.6 Gg yr −1 in 1994 to a maximum of 54.4±17.1 Gg yr −1 in 2011, declining to 52.5±20.1 Gg yr −1 in 2014 or 7.2±2.8 Tg-CO 2 eq yr −1. Analysis of mixing ratio enhancements above regional background atmospheric levels suggests substantial emissions from North America, Asia and Europe. Global HFC emissions (so called "bottom up" emissions) reported by the United Nations Framework Convention on Climate Change (UNFCCC) are based on cumulative national emission data reported to the UNFCCC, which in turn are based on national consumption data. There appears to be a significant underestimate of "bottom-up" global emissions of HFC-152a, possibly arising from largely underestimated USA emissions and undeclared Asian emissions.