Abstract
Recent climate change mitigation strategies rely on the reduction of methane (CH4) emissions. Carbon and hydrogen isotope ratio (δ13CCH4 and δ2HCH4) measurements can be used to distinguish sources and thus to understand the CH4 budget better. The CH4 emission estimates by models are sensitive to the isotopic signatures assigned to each source category, so it is important to provide representative estimates of the different CH4 source isotopic signatures worldwide. We present new measurements of isotope signatures of various, mainly anthropogenic, CH4 sources in Europe, which represent a substantial contribution to the global dataset of source isotopic measurements from the literature, especially for δ2HCH4. They improve the definition of δ13CCH4 from waste sources, and demonstrate the use of δ2HCH4 for fossil fuel source attribution. We combined our new measurements with the last published database of CH4 isotopic signatures and with additional literature, and present a new global database. We found that microbial sources are generally well characterised. The large variability in fossil fuel isotopic compositions requires particular care in the choice of weighting criteria for the calculation of a representative global value. The global dataset could be further improved by measurements from African, South American, and Asian countries, and more measurements from pyrogenic sources. We improved the source characterisation of CH4 emissions using stable isotopes and associated uncertainty, to be used in top-down studies. We emphasise that an appropriate use of the database requires the analysis of specific parameters in relation to source type and the region of interest. The final version of the European CH4 isotope database coupled with a global inventory of fossil and non-fossil δ13CCH4 and δ2HCH4 source signature measurements is available at 10.24416/UU01-YP43IN .
Original language | English |
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Pages (from-to) | 4365-4386 |
Number of pages | 22 |
Journal | Earth System Science Data |
Volume | 14 |
Issue number | 9 |
DOIs | |
Publication status | Published - 23 Sept 2022 |
Bibliographical note
Funding Information:We thank all the staff from different organisations involved in the MEMO2, CoMet, and ROMEO projects who participated in the sample collection.We acknowledge the technical staff at UU and RHUL for the maintenance of the IRMS systems. This work was supported by the ITN project “Methane goes Mobile – Measurements and Modelling” (MEMO2; https://h2020-memo2.eu/ , last access: 3 November 2021).
Funding Information:
Marie Skłodowska-Curie Actions, Horizon 2020 Innovative Training Networks founded under the grant agreement no. 722479: https://cordis.europa.eu/project/id/722479 (last access: 21 September 2022)
Publisher Copyright:
© 2022 Malika Menoud et al.
Funding
We thank all the staff from different organisations involved in the MEMO2, CoMet, and ROMEO projects who participated in the sample collection.We acknowledge the technical staff at UU and RHUL for the maintenance of the IRMS systems. This work was supported by the ITN project “Methane goes Mobile – Measurements and Modelling” (MEMO2; https://h2020-memo2.eu/ , last access: 3 November 2021). Marie Skłodowska-Curie Actions, Horizon 2020 Innovative Training Networks founded under the grant agreement no. 722479: https://cordis.europa.eu/project/id/722479 (last access: 21 September 2022)
Keywords
- Silesian coal basin
- Atmospheric methane
- Carbon-dioxide
- Source signatures
- Fossil-fuel
- Bacteriogenic methane
- Transport mechanisms
- Bacterial methane
- Natural gases
- Ch4 oxidation