A decline in emissions of CFC-11 and related chemicals from eastern China

Park, Sunyoung; Western, Luke M.; Saito, Takuya; Redington, Alison L.; Henne, Stephan; Fang, Xuekun; Prinn, Ronald G.; Manning, Alistair J.; Montzka, S. A.; Fraser, Paul J.; Ganesan, Anita L.; Harth, Christina M.; Kim, Jooil; Krummel, Paul B.; Liang, Qing; Mühle, Jens; O’Doherty, Simon; Park, Hyeri; Park, Mi-Kyung; Reimann, Stefan; Salameh, Peter K.; Weiss, Ray F.; Rigby, Matthew

doi:10.1038/s41586-021-03277-w

Cited by 82 publications

(108 citation statements)

References 38 publications

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“…Furthermore, based on a range of considerations and very different observational constraints, an increase in the CFC-11 bank in eastern China of up to 112 Gg CFC-11 has been estimated through to 2019 (ref. 25 ), which is more consistent with the lower range of global bank increases, considering that this region accounts for about half of global excess emissions since 2013 (refs. 1,3,25 ).…”

Section: Estimating Enhanced Production and Bankssupporting

confidence: 68%

“…29 ). Such large increases also seem unlikely because they would have to come from regions other than those dominating past CFC use (the USA and the European Union), given the observational evidence suggesting no recent increases from these regions 1,3 and a near complete decline by 2019 in excess CFC-11 emissions from eastern China 25 (Extended Data Fig. 7).…”

Section: Estimating Excess Global Emissionsmentioning

confidence: 99%

“…While the results from MLO reveal that emission reductions in eastern Asia contributed to the global decline, accurate mapping or quantification of emission changes in eastern Asia is prevented by the large distance between these locations. In the accompanying paper 25 , an inverse analysis of CFC-11 concentration enhancements at two eastern Asian sites reveals substantial emission reductions in eastern China after 2017. When considered relative to the global CFC-11 emissions reported here, those regional influences account for 60 ± 30% of the global emission decline in 2019 relative to the 2014−2017 mean.…”

mentioning

confidence: 94%

“…The rate of decline in the global mole fraction, the hemispheric mole fraction difference, and global and eastern China emissions 25 all returned to pre-2013 values before the end of 2019, and so were not associated with the SARS-CoV-2 outbreak, which caused reduced economic activity beginning in late January of 2020 (ref. 26 ).…”

mentioning

confidence: 99%

“…For comparison, an analysis of regional measurements suggests an increase in CFC-11-containing banks in eastern China of up to 112 Gg in 2019 (ref. 25 ). Although the size of the existing global foam banks is uncertain, relative to a bank of 1,300−1,600 Gg (refs.…”

mentioning

confidence: 99%

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A decline in global CFC-11 emissions during 2018−2019

Montzka

Dutton

Portmann

et al. 2021

Nature

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The atmospheric concentration of trichlorofluoromethane (CFC-11) has been in decline since the production of ozone-depleting substances was phased out under the Montreal Protocol 1,2. Since 2013, the concentration decline of CFC-11 slowed unexpectedly owing to increasing emissions, probably from unreported production, which, if sustained, would delay the recovery of the stratospheric ozone layer 1-12. Here we report an accelerated decline in the global mean CFC-11 concentration during 2019 and 2020, derived from atmospheric concentration measurements at remote sites around the world. We find that global CFC-11 emissions decreased by 18 ± 6 gigagrams per year (26 ± 9 per cent; one standard deviation) from 2018 to 2019, to a 2019 value (52 ± 10 gigagrams per year) that is similar to the 2008−2012 mean. The decline in global emissions suggests a substantial decrease in unreported CFC-11 production. If the sharp decline in unexpected global emissions and unreported production is sustained, any associated future ozone depletion is likely to be limited, despite an increase in the CFC-11 bank (the amount of CFC-11 produced, but not yet emitted) by 90 to 725 gigagrams by the beginning of 2020. After the discovery 1 that global emissions and probably also production of the potent ozone-depleting chemical CFC-11 increased after 2012despite Montreal Protocol controls banning production by 2010scientists, industry experts, policy makers and others sought information to enable rapid mitigation and to ensure protection of the ozone layer 2-12. Although these efforts added clarity to our understanding, uncertainties remain that could hinder effective and rapid mitigation of the unexpected CFC-11 emissions and prevent reliable estimates of the additional damage expected for the ozone layer. These uncertainties include the total amount of unreported CFC-11 production and how it was used (which determines the CFC-11 'bank', the amount still existing in foams, chillers and so on, that has yet to escape to the atmosphere), the regions responsible for new production, and the extent to which unreported CFC-11 production continues. At least 40% to 60% of the enhancement in global emission during 2014−2017 has been attributed to eastern mainland China 3. Even before this specific attribution, China conducted internal inspections in late 2018 and 2019 and announced renewed enforcement and enhanced inspection measures as elements of a broad plan to mitigate any illicit CFC production and use 13. Effective and rapid mitigation of the renewed production and emission probably depends in part on the success of this Chinese initiative. It is difficult to predict its effectiveness for rapidly mitigating global emission enhancements, given that only small amounts of CFC-11 production were discovered in these inspections relative to the observationally derived global and regional emission increase 3,9,13,14 , and because the regions responsible for the remaining portion of the global emission increase have yet to be identified 3. The most likely ...

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Section: Estimating Enhanced Production and Bankssupporting

confidence: 68%

Section: Estimating Excess Global Emissionsmentioning

confidence: 99%

mentioning

confidence: 94%

mentioning

confidence: 99%

mentioning

confidence: 99%

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A decline in global CFC-11 emissions during 2018−2019

Montzka

Dutton

Portmann

et al. 2021

Nature

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A review on atmospheric volatile halogenated hydrocarbons in China: ambient levels, trends and human health risks

Ji,

Zhang,

Yan

et al. 2023

Air Qual Atmos Health

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Stratospheric ozone, UV radiation, and climate interactions

Bernhard

Bais

Aucamp³

et al. 2023

Photochem Photobiol Sci

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This assessment provides a comprehensive update of the effects of changes in stratospheric ozone and other factors (aerosols, surface reflectivity, solar activity, and climate) on the intensity of ultraviolet (UV) radiation at the Earth’s surface. The assessment is performed in the context of the Montreal Protocol on Substances that Deplete the Ozone Layer and its Amendments and Adjustments. Changes in UV radiation at low- and mid-latitudes (0–60°) during the last 25 years have generally been small (e.g., typically less than 4% per decade, increasing at some sites and decreasing at others) and were mostly driven by changes in cloud cover and atmospheric aerosol content, caused partly by climate change and partly by measures to control tropospheric pollution. Without the Montreal Protocol, erythemal (sunburning) UV irradiance at northern and southern latitudes of less than 50° would have increased by 10–20% between 1996 and 2020. For southern latitudes exceeding 50°, the UV Index (UVI) would have surged by between 25% (year-round at the southern tip of South America) and more than 100% (South Pole in spring). Variability of erythemal irradiance in Antarctica was very large during the last four years. In spring 2019, erythemal UV radiation was at the minimum of the historical (1991–2018) range at the South Pole, while near record-high values were observed in spring 2020, which were up to 80% above the historical mean. In the Arctic, some of the highest erythemal irradiances on record were measured in March and April 2020. For example in March 2020, the monthly average UVI over a site in the Canadian Arctic was up to 70% higher than the historical (2005–2019) average, often exceeding this mean by three standard deviations. Under the presumption that all countries will adhere to the Montreal Protocol in the future and that atmospheric aerosol concentrations remain constant, erythemal irradiance at mid-latitudes (30–60°) is projected to decrease between 2015 and 2090 by 2–5% in the north and by 4–6% in the south due to recovering ozone. Changes projected for the tropics are ≤ 3%. However, in industrial regions that are currently affected by air pollution, UV radiation will increase as measures to reduce air pollutants will gradually restore UV radiation intensities to those of a cleaner atmosphere. Since most substances controlled by the Montreal Protocol are also greenhouse gases, the phase-out of these substances may have avoided warming by 0.5–1.0 °C over mid-latitude regions of the continents, and by more than 1.0 °C in the Arctic; however, the uncertainty of these calculations is large. We also assess the effects of changes in stratospheric ozone on climate, focusing on the poleward shift of climate zones, and discuss the role of the small Antarctic ozone hole in 2019 on the devastating “Black Summer” fires in Australia. Additional topics include the assessment of advances in measuring and modeling of UV radiation; methods for determining personal UV exposure; the effect of solar radiation management (stratospheric aerosol injections) on UV radiation relevant for plants; and possible revisions to the vitamin D action spectrum, which describes the wavelength dependence of the synthesis of previtamin D3 in human skin upon exposure to UV radiation. Graphical abstract

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A decline in emissions of CFC-11 and related chemicals from eastern China

Cited by 82 publications

References 38 publications

A decline in global CFC-11 emissions during 2018−2019

A decline in global CFC-11 emissions during 2018−2019

A review on atmospheric volatile halogenated hydrocarbons in China: ambient levels, trends and human health risks

Stratospheric ozone, UV radiation, and climate interactions

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