Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Upward revision of global fossil fuel methane emissions based on isotope database

A Corrigendum to this article was published on 15 February 2017


Methane has the second-largest global radiative forcing impact of anthropogenic greenhouse gases after carbon dioxide, but our understanding of the global atmospheric methane budget is incomplete. The global fossil fuel industry (production and usage of natural gas, oil and coal) is thought to contribute 15 to 22 per cent of methane emissions1,2,3,4,5,6,7,8,9,10 to the total atmospheric methane budget11. However, questions remain regarding methane emission trends as a result of fossil fuel industrial activity and the contribution to total methane emissions of sources from the fossil fuel industry and from natural geological seepage12,13, which are often co-located. Here we re-evaluate the global methane budget and the contribution of the fossil fuel industry to methane emissions based on long-term global methane and methane carbon isotope records. We compile the largest isotopic methane source signature database so far, including fossil fuel, microbial and biomass-burning methane emission sources. We find that total fossil fuel methane emissions (fossil fuel industry plus natural geological seepage) are not increasing over time, but are 60 to 110 per cent greater than current estimates1,2,3,4,5,6,7,8,9,10 owing to large revisions in isotope source signatures. We show that this is consistent with the observed global latitudinal methane gradient. After accounting for natural geological methane seepage12,13, we find that methane emissions from natural gas, oil and coal production and their usage are 20 to 60 per cent greater than inventories1,2. Our findings imply a greater potential for the fossil fuel industry to mitigate anthropogenic climate forcing, but we also find that methane emissions from natural gas as a fraction of production have declined from approximately 8 per cent to approximately 2 per cent over the past three decades.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Comparison of δ13CFF, δ13Cmic and δ13CBB source signatures from this study (red) and those used in 15 previous top-down studies (blue; see Supplementary Information section 8 for references).
Figure 2: Fossil fuel and microbial source CH4 budget terms.
Figure 3: Global FER long-term trend with mean values shown in solid black.

Similar content being viewed by others


  1. US Environmental Protection Agency. Summary Report: Global Anthropogenic Non-CO2 Greenhouse Gas Emissions: 1990–2030 (Office of Atmospheric Programs, Climate Change Division, US EPA, 2012)

  2. European Commission—Joint Research Centre (JRC)/Netherlands Environmental Assessment Agency (PBL). Emission Database for Global Atmospheric Research (EDGAR), release version 4.2, (2014)

  3. Bousquet, P. et al. Contribution of anthropogenic and natural sources to atmospheric methane variability. Nature 443, 439–443 (2006)

    Article  CAS  ADS  Google Scholar 

  4. Mikaloff Fletcher, S. E., Tans, P. P., Bruhwiler, L. M., Miller, J. B. & Heimann, M. CH4 sources estimated from atmospheric observations of CH4 and its 13C/12C isotopic ratios: 1. Inverse modeling of source processes. Glob. Biogeochem. Cycles 18, GB4004 (2004)

    ADS  Google Scholar 

  5. Fraser, A. et al. Estimating regional methane surface fluxes: the relative importance of surface and GOSAT mole fraction measurements. Atmos. Chem. Phys. 13, 5697–5713 (2013)

    Article  ADS  Google Scholar 

  6. Wang, J. S. et al. A 3-D model analysis of the slowdown and interannual variability in the methane growth rate from 1988 to 1997. Glob. Biogeochem. Cycles 18, GB3011 (2004)

    Article  ADS  Google Scholar 

  7. Chen, Y.-H. & Prinn, R. G. Estimation of atmospheric methane emissions between 1996 and 2001 using a three-dimensional global chemical transport model. J. Geophys. Res. Atmos. 111, D10307 (2006)

    ADS  Google Scholar 

  8. Bergamaschi, P. et al. Inverse modeling of global and regional CH4 emissions using SCIAMACHY satellite retrievals. J. Geophys. Res. 114, D22301 (2009)

    Article  ADS  Google Scholar 

  9. Schwietzke, S., Griffin, W. M., Matthews, H. S. & Bruhwiler, L. M. P. Natural gas fugitive emissions rates constrained by global atmospheric methane and ethane. Environ. Sci. Technol. 48, 7714–7722 (2014)

    Article  CAS  ADS  Google Scholar 

  10. Quay, P. et al. The isotopic composition of atmospheric methane. Glob. Biogeochem. Cycles 13, 445–461 (1999)

    Article  CAS  ADS  Google Scholar 

  11. Kirschke, S. et al. Three decades of global methane sources and sinks. Nat. Geosci. 6, 813–823 (2013)

    Article  CAS  ADS  Google Scholar 

  12. Etiope, G., Lassey, K. R., Klusman, R. W. & Boschi, E. Reappraisal of the fossil methane budget and related emission from geologic sources. Geophys. Res. Lett. 35, L09307 (2008)

    Article  ADS  Google Scholar 

  13. Ciais, P. et al. in Working Group I Contribution To The IPCC Fifth Assessment Report. Climate Change 2013—The Physical Science Basis (eds Stocker, T. F. et al..) Ch. 6, 465–570 (Cambridge Univ. Press, 2013)

    Google Scholar 

  14. Sherwood, O., Schwietzke, S., Arling, V. & Etiope, G. Global Inventory of Fossil and Non-fossil Methane δ13C Source Signature Measurements for Improved Atmospheric Modeling (NOAA/ESRL/GMD, 2016)

  15. Alvarez, R. A., Pacala, S. W., Winebrake, J. J., Chameides, W. L. & Hamburg, S. P. Greater focus needed on methane leakage from natural gas infrastructure. Proc. Natl Acad. Sci. USA 109, 6435–6440 (2012)

    Article  CAS  ADS  Google Scholar 

  16. US Energy Information Administration International Energy Statistics database (2016)

  17. Whiticar, M. J. in Organic Geochemistry (eds Durand, B. & Behar, F. ) Vol. 16, 531–548 (Pergamon, 1990)

    Article  CAS  Google Scholar 

  18. Milkov, A. V. Worldwide distribution and significance of secondary microbial methane formed during petroleum biodegradation in conventional reservoirs. Org. Geochem. 42, 184–207 (2011)

    Article  CAS  Google Scholar 

  19. Meslé, M., Dromart, G. & Oger, P. Microbial methanogenesis in subsurface oil and coal. Res. Microbiol. 164, 959–972 (2013)

    Article  Google Scholar 

  20. NOAA Earth System Research Laboratory Global Monitoring Division Global Greenhouse Gas Reference Network (2016)

  21. Schaefer, H. et al. A 21st century shift from fossil-fuel to biogenic methane emissions indicated by 13CH4 . Science 352, 80–84 (2016)

    Article  CAS  ADS  Google Scholar 

  22. US Environmental Protection Agency. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990–2014 (2016)

  23. Randerson, J. T., Chen, Y., van der Werf, G. R., Rogers, B. M. & Morton, D. C. Global burned area and biomass burning emissions from small fires. J. Geophys. Res. 117, G04012 (2012)

    Article  ADS  Google Scholar 

  24. Sapart, C. J. et al. Natural and anthropogenic variations in methane sources during the past two millennia. Nature 490, 85–88 (2012)

    Article  CAS  ADS  Google Scholar 

  25. Mischler, J. A. et al. Carbon and hydrogen isotopic composition of methane over the last 1000 years. Glob. Biogeochem. Cycles 23, GB4024 (2009)

    Article  Google Scholar 

  26. Sowers, T. Atmospheric methane isotope records covering the Holocene period. Quat. Sci. Rev. 29, 213–221 (2010)

    Article  ADS  Google Scholar 

  27. Krol, M. et al. The two-way nested global chemistry-transport zoom model TM5: algorithm and applications. Atmos. Chem. Phys. 5, 417–432 (2005)

    Article  CAS  ADS  Google Scholar 

  28. Schwietzke, S., Griffin, W. M., Matthews, H. S. & Bruhwiler, L. M. P. Global bottom-up fossil fuel fugitive methane and ethane emissions inventory for atmospheric modeling. ACS Sustain. Chem. Eng. 2, 1992–2001 (2014)

    CAS  Google Scholar 

  29. International Energy Agency Coal Mine Methane in China: A Budding Asset with the Potential to Bloom (2009)

  30. Lassey, K. R., Lowe, D. C. & Smith, A. M. The atmospheric cycling of radiomethane and the ‘fossil fraction’ of the methane source. Atmos. Chem. Phys. 7, 2141–2149 (2007)

    Article  CAS  ADS  Google Scholar 

Download references


We thank J. Randerson, K. Johnson, A. Cole, C. Itle, T. Wirth, T. Capehart, S. Montzka, and R. Klusman for comments and discussions. We acknowledge M. Schoell and A. Ionescu for contributing δ13Csource data. This research was supported by a National Research Council RAP fellowship and a CIRES IRP grant.

Author information

Authors and Affiliations



S.S. was responsible for study design, box-model development, analysis of TM5 results, manuscript preparation, and helped provide data. P.P.T. and J.B.M. helped with study design and improved the manuscript. O.A.S., G.E., E.J.D., S.E.M., V.A.A., B.H.V. and J.W.C.W. provided data and improved the manuscript. L.M.P.B. was responsible for TM5 modelling, helped with model analysis, and improved the manuscript.

Corresponding author

Correspondence to Stefan Schwietzke.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Additional information

The reconstructed atmospheric global average δ13Catm data for 1984–1998 are from ref. 21 and global δ13Cice data are from ref. 24.

Reviewer Information

Nature thanks G. Allen, M. Heimann and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Supplementary information

Supplementary Information

This file contains a list of acronyms, the box-model descriptions, atmospheric measurements used, isotopic signature database details (data, explanations, and weighting schemes, paleo CH4 budget analysis, global latitudinal CH4 gradient simulations (TM5 model), and all sensitivity analyses. (PDF 2893 kb)

PowerPoint slides

Source data

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Schwietzke, S., Sherwood, O., Bruhwiler, L. et al. Upward revision of global fossil fuel methane emissions based on isotope database. Nature 538, 88–91 (2016).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing Anthropocene

Sign up for the Nature Briefing: Anthropocene newsletter — what matters in anthropocene research, free to your inbox weekly.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing: Anthropocene