Projects per year
Abstract
The growth in global methane (CH4) concentration, which had been ongoing since the industrial revolution, stalled around the year 2000 before resuming globally in 2007. We evaluate the role of the hydroxyl radical (OH), the major CH4 sink, in the recent CH4 growth. We also examine the influence of systematic uncertainties in OH concentrations on CH4 emissions inferred from atmospheric observations. We use observations of 1,1,1-trichloroethane (CH3CCl3), which is lost primarily through reaction with OH, to estimate OH levels as well as CH3CC3 emissions, which have uncertainty that previously limited the accuracy of OH estimates. We find a 64–70% probability that a decline in OH has contributed to the post-2007 methane rise. Our median solution suggests that CH4 emissions increased relatively steadily during the late 1990s and early 2000s, after which growth was more modest. This solution obviates the need for a sudden statistically significant change in total CH4 emissions around the year 2007 to explain the atmospheric observations and can explain some of the decline in the atmospheric 13CH4/12CH4 ratio and the recent growth in C2H6. Our approach indicates that significant OH-related uncertainties in the CH4 budget remain, and we find that it is not possible to implicate, with a high degree of confidence, rapid global CH4 emissions changes as the primary driver of recent trends when our inferred OH trends and these uncertainties are considered.
Original language | English |
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Pages (from-to) | 5373-5377 |
Number of pages | 5 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 114 |
Issue number | 21 |
Early online date | 17 Apr 2017 |
DOIs | |
Publication status | Published - 23 May 2017 |
Keywords
- methane
- hydroxyl
- inversion
- methyl chloroform
- 1,1,1-trichloroethane
Fingerprint
Dive into the research topics of 'Role of atmospheric oxidation in recent methane growth'. Together they form a unique fingerprint.Projects
- 6 Finished
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NERC highlight "Closing the global methane budget"
Rigby, M. L. (Principal Investigator)
1/05/16 → 20/02/21
Project: Research
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Verifying national HFC emissions
Rigby, M. L. (Principal Investigator)
4/08/15 → 31/08/22
Project: Research
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Advanced computing architecture to support the estimation and reporting of UK GHG emissions
Rigby, M. L. (Principal Investigator)
13/11/13 → 13/10/15
Project: Research
Profiles
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Professor Anita L Ganesan
- School of Geographical Sciences - Professor of Atmospheric Chemistry
- Atmospheric Chemistry
- Cabot Institute for the Environment
Person: Academic , Member
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Professor Simon O'Doherty
- School of Chemistry - Visiting Professor
- Cabot Institute for the Environment
- Atmospheric Chemistry
Person: Member, Group lead, Honorary and Visiting Academic