Articles | Volume 22, issue 23
Research article
 | Highlight paper
05 Dec 2022
Research article | Highlight paper |  | 05 Dec 2022

Estimating emissions of methane consistent with atmospheric measurements of methane and δ13C of methane

Sourish Basu, Xin Lan, Edward Dlugokencky, Sylvia Michel, Stefan Schwietzke, John B. Miller, Lori Bruhwiler, Youmi Oh, Pieter P. Tans, Francesco Apadula, Luciana V. Gatti, Armin Jordan, Jaroslaw Necki, Motoki Sasakawa, Shinji Morimoto, Tatiana Di Iorio, Haeyoung Lee, Jgor Arduini, and Giovanni Manca


Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on acp-2022-317', Anonymous Referee #2, 19 Jul 2022
    • AC1: 'Reply to anonymous reviewer 2', Sourish Basu, 30 Aug 2022
    • AC4: 'Addendum to reply', Sourish Basu, 01 Sep 2022
  • RC2: 'Comment on acp-2022-317', Martin Manning, 21 Jul 2022
    • AC2: 'Reply to comments by Martin Manning', Sourish Basu, 30 Aug 2022
  • RC3: 'Comment on acp-2022-317', Anonymous Referee #1, 16 Aug 2022
    • AC3: 'Reply to anonymous referee 1', Sourish Basu, 31 Aug 2022

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
AR by Sourish Basu on behalf of the Authors (01 Sep 2022)  Author's response   Author's tracked changes   Manuscript 
ED: Publish subject to minor revisions (review by editor) (29 Sep 2022) by Maria Kanakidou
AR by Sourish Basu on behalf of the Authors (30 Sep 2022)  Author's response   Author's tracked changes   Manuscript 
ED: Publish subject to technical corrections (01 Oct 2022) by Maria Kanakidou
AR by Sourish Basu on behalf of the Authors (28 Oct 2022)  Author's response   Manuscript 
Executive editor
Methane is a potent greenhouse gas and an important sink of atmospheric OH radicals, which determine the global atmospheric oxidation capacity. CH4 has increased since pre-industrial times until the year 2000, after which its global concentration has remained relatively stable. Since 2007, it is rapidly increasing again for reasons that are not well understood. The current paper analyses source specific methane emissions that are likely responsible for the recent increase. Global CH4 sources are determined using variational inversion based on measurements of methane and its isotope signatures (δ13C). This latter provide better constraints on the contributions of microbial and fossil fuel CH4 sources than the concentrations alone. The analysis points to a more strongly increasing contribution of microbial sources since 2007 than predicted by previous assessments (Global Carbon Project). These findings have the potential to lead to a major reassessment of the global methane budget.
Short summary
Atmospheric methane (CH4) has been growing steadily since 2007 for reasons that are not well understood. Here we determine sources of methane using a technique informed by atmospheric measurements of CH4 and its isotopologue 13CH4. Measurements of 13CH4 provide for better separation of microbial, fossil, and fire sources of methane than CH4 measurements alone. Compared to previous assessments such as the Global Carbon Project, we find a larger microbial contribution to the post-2007 increase.
Final-revised paper