Towards a further understanding of the magnitude and underlying cause for the recent increase in global CFC-11 emission
Abstract
The rate of decline measured for mole fractions of the ozone-depleting gas CFC-11 in the remote atmosphere has slowed substantially in recent years. This slowdown and other aspects of the observations point to an increase in global CFC-11 emission since 2012, and 3-D modeling of the observations supports this conclusion (Montzka et al., 2018; https:doi.org/10.1038/s41586-018-0106-2). Measurements at our Hawaiian station (Mauna Loa) indicate that some part of the CFC-11 emission increase arises from eastern Asia. This emission increase is highly unexpected because global CFC-11 production was reportedly phased out in 2010. Updated results since our recent publication reveal that CFC-11 concentrations continue to decrease unexpectedly slowly and the global mean emission rate inferred for 2017 remains substantially elevated. This presentation will update the evidence for increasing CFC-11 emissions that appear to be associated with new production subsequent to the reported 2010 phase-out, which would violate international agreements under the Montreal Protocol. We will also explore more detailed analyses of our flask and high-frequency concentration measurements of CFC-11 and other related gases at Mauna Loa to search for more precise clues on the sources of the increased CFC-11 emission.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A32A..01M
- Keywords:
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- 0340 Middle atmosphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0341 Middle atmosphere: constituent transport and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 3305 Climate change and variability;
- ATMOSPHERIC PROCESSESDE: 3334 Middle atmosphere dynamics;
- ATMOSPHERIC PROCESSES