scholarly journals Toward resolving the mysterious budget discrepancy of ozone-depleting CCl<sub>4</sub>: An analysis of top-down emissions from China

2018 ◽  
Author(s):  
Sunyoung Park ◽  
Shanlan Li ◽  
Jens Mühle ◽  
Simon O'Doherty ◽  
Ray F. Weiss ◽  
...  

Abstract. Emissive production and use of carbon tetrachloride (CCl4), one of the first-generation ozone-depleting substances, have been banned by the Montreal Protocol with the 2010 phase-out for developing countries, but production and consumption for non-dispersive use as a chemical feedstock and as process agent are still allowed. Here, we present evidence that significant unreported emissions of CCl4 still persist, based on the high frequency and magnitude of CCl4 pollution events observed in the 8-year real time atmospheric measurement record at Gosan station, a regional background monitoring site in East Asia. From this we estimate top-down emissions of CCl4 amounting to 23.6 ± 7.1 Gg yr−1 from 2011 to 2015 for China, in contrast to the 4.3–5.2 Gg yr−1 reported as the most up-to-date post-2010 Chinese bottom-up emissions. The missing emissions (~ 19 Gg yr−1) for China are highly significant, contributing about 54 % of global CCl4 emissions. We show that 89 ± 6 % of the CCl4 enhancements observed at Gosan can be accounted for by fugitive emissions of CCl4 occurring at the factory level during the production of CH3Cl, CH2Cl2, CHCl3 and C2Cl4 (PCE) and feedstock and solvent use in chemical manufacturing industries. Thus, it is crucial to implement technical improvements and better regulation strategies to reduce the evaporative losses of CCl4 occurring at the factory and/or process level.

2018 ◽  
Vol 18 (16) ◽  
pp. 11729-11738 ◽  
Author(s):  
Sunyoung Park ◽  
Shanlan Li ◽  
Jens Mühle ◽  
Simon O'Doherty ◽  
Ray F. Weiss ◽  
...  

Abstract. Carbon tetrachloride (CCl4) is a first-generation ozone-depleting substance, and its emissive use and production were globally banned by the Montreal Protocol with a 2010 phase-out; however, production and consumption for non-dispersive use as a chemical feedstock and as a process agent are still allowed. This study uses the high frequency and magnitude of CCl4 pollution events from an 8-year real-time atmospheric measurement record obtained at Gosan station (a regional background monitoring site in East Asia) to present evidence of significant unreported emissions of CCl4. Top-down emissions of CCl4 amounting to 23.6±7.1 Gg yr−1 from 2011 to 2015 are estimated for China, in contrast to the most recently reported, post-2010, Chinese bottom-up emissions of 4.3–5.2 Gg yr−1. The missing emissions (∼19 Gg yr−1) for China contribute to approximately 54 % of global CCl4 emissions. It is also shown that 89 %±6 % of CCl4 enhancements observed at Gosan are related to CCl4 emissions from the production of CH3Cl, CH2Cl2, CHCl3 and C2Cl4 and its usage as a feedstock and process agent in chemical manufacturing industries. Specific sources and processes are identified using statistical methods, and it is considered highly unlikely that CCl4 is emitted by dispersive uses such as old landfills, contaminated soils and solvent usage. It is thus crucial to implement technical improvements and better regulation strategies to reduce evaporative losses of CCl4 occurring at the factory and/or process levels.


2016 ◽  
Author(s):  
Peter G. Simmonds ◽  
Matthew Rigby ◽  
Archibold McCulloch ◽  
Simon O'Doherty ◽  
Dickon Young ◽  
...  

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.


2017 ◽  
Vol 17 (7) ◽  
pp. 4641-4655 ◽  
Author(s):  
Peter G. Simmonds ◽  
Matthew Rigby ◽  
Archie McCulloch ◽  
Simon O'Doherty ◽  
Dickon Young ◽  
...  

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. 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 CO2 equivalent units (CO2 eq.) 0.76 ± 0.1 Gt yr−1, compared with 483 ± 70 Gg yr−1 (0.82 ± 0.1 Gt yr−1 CO2 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 CO2 eq.) in 2015 compared to 240 ± 50 Gg yr−1 (0.47 ± 0.08 Gt yr−1 CO2 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.


Author(s):  
Alexandra Coghlan

Having looked at the external and internal challenges facing the move towards more sustainable tourism, and the impacts of tourism, you should now be wondering how sustainability in tourism can be turned into more than an ideal. Perhaps one of the most obvious way to achieve this is simply to regulate the sector. After all regulation worked for the ozone layer: scientists raised the alarm in the 1970s that a hole was appearing in the atmosphere’s ozone layer, caused by Ozone Depleting Substances or ODS (most notably CFCs) and resulting in adverse effects on human health and the environment. By 1987 the Montreal Protocol was established to phase out the use of ODS, and by June 2015, all countries in the United Nations, the Cook Islands, Holy See, Niue and the supranational European Union had ratified the original Protocol. The result was a 98% drop in ODS since ratification, and the hole is expected to have fully repaired itself by 2050. A significant achievement in terms of international cooperation, based on scientific advice.


Respuestas ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 65-74
Author(s):  
Juan José García Pabón

This article is intended to draw attention of the community in general to the changes that have taken place in refrigeration and air conditioning industry of the HFC refrigerants currently used. The HFCs are not Ozone-depleting substances, but the some HFCs are greenhouse gases with very high potential for global warming (GWPs). Thus, more than 150 countries sign up the Kigali Amendment in 2016, establishing the decreasing of the production and consumption of the HFCs. This paper briefly describes the problems surrounding the HFCs and summarizes the fluids considered as alternatives for the main HFCs used in refrigeration systems presented in the scientific literature. In addition, the outlook and the current situation of the HFC withdrawal process in Colombia are analyzed.


2018 ◽  
Author(s):  
Dimitrios K. Papanastasiou ◽  
Allison Beltrone ◽  
Paul Marshall ◽  
James B. Burkholder

Abstract. Hydrochlorofluorocarbons (HCFCs) are ozone depleting substances and potent greenhouse gases that are controlled under the Montreal Protocol. However, the majority of the 274 HCFCs included in Annex C of the protocol do not have reported global warming potentials (GWPs) that are used to guide the phase-out of HCFCs and the future phase-down of hydrofluorocarbons (HFCs). In this study, GWPs for all C1-C3 HCFCs included in Annex C are reported based on estimated atmospheric lifetimes and theoretical methods used to calculate infrared absorption spectra. Atmospheric lifetimes were estimated from a structure activity relationship (SAR) for OH radical reactivity and estimated O(1D) reactivity and UV photolysis loss processes. The HCFCs display a wide range of lifetimes and GWPs dependent on their molecular structure and H-atom content of the individual HCFC. The results from this study provide reliable policy relevant GWP metrics for the HCFCs included in the Montreal Protocol in the absence of experimentally derived metrics.


Author(s):  
Alexander Ovodenko

The chapter analyzes the impact of downstream consumer markets on environmental regime design by explaining why wealthy countries have successfully phased out industrial ozone-depleting substances (ODS) but not an agricultural pesticide known as methyl bromide under the Montreal Protocol, despite the 2005 phase-out deadline for that pesticide. Since the analysis focuses on the regulation of different sectors under the same treaty, it isolates the impact of markets without the threat of major confounding variables interfering with the conclusions. It emphasizes competitive pressures and the structure of intermediate producers in the industrial and agricultural markets employing ODS to explain why methyl bromide has been handled differently from industrial refrigerants. The findings illustrate the impacts of consumer preferences and market competition on the investments of fluoro-product companies and, in turn, on the policies of wealthy countries and rules in the ozone regime.


2020 ◽  
Author(s):  
Martin Vollmer ◽  

&lt;p&gt;We present first results on atmospheric abundances and inferred emissions of the previously undetected ozone depleting hydrochlorofluorocarbon HCFC-132b (1,2-dichloro-1,1-difluoroethane). In addition we report significant updates on observations and inferred emissions for HCFC-133a (2-chloro-1,1,1-trifluoroethane) and HCFC-31 (chlorofluoromethane). All three compounds are Ozone Depleting Substances (ODSs) and their productions are regulated under the Montreal Protocol on Substances that Deplete the Ozone Layer. However, they are not known as end-user products from which potential emissions to the atmosphere could occur. Rather, we hypothesize that the compounds are emitted as byproducts during the production of hydrofluorocarbons (HFCs). If this holds true, then the phase-out regulations of the Protocol do not apply to them, nevertheless the Protocol's overarching Vienna Convention encourages the parties to minimize such ODS byproduct emissions.&lt;/p&gt;&lt;p&gt;In-situ fully intercalibrated high-precision measurements of the recently discovered HCFC-132b have been made for several years at the stations of the Advanced Global Atmospheric Gases Experiment (AGAGE) and are complemented with measurements from archived air samples (1978 &amp;#8211; present) of the Cape Grim Air Archive. Based on these measurements we reconstruct global HCFC-132b trends showing its first appearance in the atmosphere in the late 1990s, followed by a general growth in the atmosphere to current globally-averaged mole fractions of approx. 0.13 ppt (picomol mol&lt;sup&gt;-1&lt;/sup&gt;). Global emissions, which are derived from these observations using the AGAGE 12-box model, show a general increase to approx. 1 Gg yr&lt;sup&gt;-1&lt;/sup&gt; in 2019. Observation-based top-down regional emission estimates for the East-Asian region, as derived from a Bayesian inversion with the FLEXPART Lagrangian model, can explain all of the global emissions within the uncertainties of the method. Half of these emissions are allocated to Eastern China, a region where enhanced emissions for other ODSs were previously found. Emissions from Europe are comparably insignificant, but an analysis of the source locations supports the hypothesis that HCFC-132b emissions are a byproduct from HFC production. In addition to HCFC-132b, we present significant updates on observations of HCFC-133a and HCFC-31. HCFC-133a measurements are now fully integrated into the AGAGE network and provide a wealth of atmospheric observations. Similar to HCFC-132b, we show, for example, that abundances and global emissions of these two compounds have generally increased over the last few years.&lt;/p&gt;


2016 ◽  
Vol 17 (2) ◽  
pp. 472-479 ◽  
Author(s):  
Jiefeng Kang ◽  
Jianyi Lin ◽  
Shenghui Cui ◽  
Xiangyang Li

Providing a comprehensive insight, water footprint (WF) is widely used to analyze and address water-use issues. In this study, a hybrid of bottom-up and top-down methods is applied to calculate, from production and consumption perspectives, the WF for Xiamen city from 2001 to 2012. Results show that the average production WF of Xiamen was 881.75 Mm3/year and remained relatively stable during the study period, while the consumption WF of Xiamen increased from 979.56 Mm3/year to 1,664.97 Mm3/year over the study period. Xiamen thus became a net importer of virtual water since 2001. Livestock was the largest contributor to the total WF from both production and consumption perspectives; it was followed by crops, industry, household use, and commerce. The efficiency of the production WF has increased in Xiamen, and its per capita consumption WF was relatively low. The city faces continuing growth in its consumption WF, so more attention should be paid to improving local irrigation, reducing food waste, and importing water-intensive agricultural products.


2014 ◽  
Vol 44 (3) ◽  
pp. 477-486 ◽  
Author(s):  
Gráinne De Búrca ◽  
Robert O. Keohane ◽  
Charles Sabel

This article outlines the concept of Global Experimentalist Governance (GXG). GXG is an institutionalized transnational process of participatory and multilevel problem solving, in which particular problems (and the means of addressing them) are framed in an open-ended way, and subjected to periodic revision by various forms of peer review in light of locally generated knowledge. GXG differs from other forms of international organization and transnational governance, and is emerging in various issue areas. The Montreal Protocol on ozone-depleting substances is used to illustrate how GXG functions. The conditions for the emergence of GXG are specified, as well as some of its possible benefits.


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