Global inventory of doubly substituted isotopologues of methane (Δ13CH3D and Δ12CH2D2)
Name
essd-17-6889-2025.pdf
Description
Published version
Size
3 MB
Format
Adobe PDF
Checksum (MD5)
c07b147d847706f535cd1634a0ec5502
Date Issued
December 8, 2025
Journal
Earth System Science Data
Publisher
Copernicus GmbH
Citation
Defratyka, S. M., Fernandez, J. M., Adnew, G. A., Dong, G., Douglas, P. M. J., Eldridge, D. L., Etiope, G., Giunta, T., Haghnegahdar, M. A., Hristov, A. N., Hultquist, N., Vadillo, I., Jautzy, J., Kim, J.-H., Labidi, J., Lalk, E., Leavitt, W., Li, J., Lin, L.-H., Liu, J., Ojeda, L., Ono, S., Rhim, J. H., Röckmann, T., Sherwood Lollar, B., Sivan, M., Sun, J., Ventura, G. T., Wang, D. T., Young, E. D., Zhang, N., and Arnold, T.: Global inventory of doubly substituted isotopologues of methane (Δ13CH3D and Δ12CH2D2), Earth Syst. Sci. Data, 17, 6889–6910.
Version
Final published version
Abstract
Measurements of methane (CH4) molecules containing two rare isotopes (13CH3D and 12CH2D2), also termed doubly substituted or “clumped” isotopologues, have the potential to provide two additional isotopic dimensions to help investigate the mechanisms underlying global atmospheric trends in CH4. In this work, we summarise the current state of research on doubly substituted CH4 isotopologues, with an emphasis on compiling results of all relevant work. The database comprises 1475 records compiled from the literature published until April 2025 (https://doi.org/10.5285/51ae627da5fb41b8a767ee6c653f83e6, Defratyka et al., 2025). For field samples, 40 % of records were sourced from natural gas reservoirs, while microbial terrestrial (e.g., agriculture, lake, wetland) samples account only for 12.5 %. Lakes samples contribute 75 % to collected microbial terrestrial samples. There is limited or no representation of samples coming from significant microbial CH4 sources to the atmosphere, like wetlands, agricultural practices and landfills. To date, laboratory experiments were mostly focused on microbial (28 % of samples from laboratory experiments) and pyrogenic (15 %) methanogenesis or anaerobic (16 %), and aerobic (8 %) CH4 oxidation, with only single study of photochemical oxidation via OH and Cl, which constitutes 5 % of the laboratory experiments entries. The distinct ranges of Δ13CH3D and Δ12CH2D2 values measured in these studies suggests their potential to improve our understanding of atmospheric CH4. This work provides an overview of the major gaps in measurements and identifies where further studies should be focussed to enable the highest impact on understanding global CH4.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.5194/essd-17-6889-2025
