Very Strong Atmospheric Methane Growth in the 4 Years 2014–2017:Implications for the Paris Agreement

Nisbet, E. G., Manning, M. R., Dlugokencky, E. J., Fisher, R. E., Lowry, D., Michel, S. E., Myhre, C. Lund, Platt, S. M., Allen, G., Bousquet, P., Brownlow, R., Cain, M., France, J. L., Hermansen, O., Hossaini, R., Jones, A. E., Levin, I., Manning, A. C., Myhre, G., Pyle, J. A., Vaughn, B. H., Warwick, N. J. and White, J. W. C. (2019) Very Strong Atmospheric Methane Growth in the 4 Years 2014–2017:Implications for the Paris Agreement. Global Biogeochemical Cycles, 33 (3). pp. 318-342. ISSN 0886-6236

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Abstract

Atmospheric methane grew very rapidly in 2014 (12.7 ± 0.5 ppb/year), 2015 (10.1 ± 0.7 ppb/year), 2016 (7.0 ± 0.7 ppb/year), and 2017 (7.7 ± 0.7 ppb/year), at rates not observed since the 1980s. The increase in the methane burden began in 2007, with the mean global mole fraction in remote surface background air rising from about 1,775 ppb in 2006 to 1,850 ppb in 2017. Simultaneously the 13 C/ 12 C isotopic ratio (expressed as δ 13 C CH4 ) has shifted, has shifted, now trending negative for more than a decade. The causes of methane's recent mole fraction increase are therefore either a change in the relative proportions (and totals) of emissions from biogenic and thermogenic and pyrogenic sources, especially in the tropics and subtropics, or a decline in the atmospheric sink of methane, or both. Unfortunately, with limited measurement data sets, it is not currently possible to be more definitive. The climate warming impact of the observed methane increase over the past decade, if continued at >5 ppb/year in the coming decades, is sufficient to challenge the Paris Agreement, which requires sharp cuts in the atmospheric methane burden. However, anthropogenic methane emissions are relatively very large and thus offer attractive targets for rapid reduction, which are essential if the Paris Agreement aims are to be attained.

Item Type: Article
Uncontrolled Keywords: atmospheric methane,fossil fuel methane emissions,methane isotopes,oh destruction of methane,paris agreement,wetland methane emissions,global and planetary change,environmental chemistry,environmental science(all),atmospheric science ,/dk/atira/pure/subjectarea/asjc/2300/2306
Faculty \ School: Faculty of Science > School of Environmental Sciences
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Depositing User: LivePure Connector
Date Deposited: 29 Mar 2019 14:30
Last Modified: 12 Jul 2020 23:52
URI: https://ueaeprints.uea.ac.uk/id/eprint/70379
DOI: 10.1029/2018GB006009

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