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.

California’s methane super-emitters


Methane is a powerful greenhouse gas and is targeted for emissions mitigation by the US state of California and other jurisdictions worldwide1,2. Unique opportunities for mitigation are presented by point-source emitters—surface features or infrastructure components that are typically less than 10 metres in diameter and emit plumes of highly concentrated methane3. However, data on point-source emissions are sparse and typically lack sufficient spatial and temporal resolution to guide their mitigation and to accurately assess their magnitude4. Here we survey more than 272,000 infrastructure elements in California using an airborne imaging spectrometer that can rapidly map methane plumes5,6,7. We conduct five campaigns over several months from 2016 to 2018, spanning the oil and gas, manure-management and waste-management sectors, resulting in the detection, geolocation and quantification of emissions from 564 strong methane point sources. Our remote sensing approach enables the rapid and repeated assessment of large areas at high spatial resolution for a poorly characterized population of methane emitters that often appear intermittently and stochastically. We estimate net methane point-source emissions in California to be 0.618 teragrams per year (95 per cent confidence interval 0.523–0.725), equivalent to 34–46 per cent of the state’s methane inventory8 for 2016. Methane ‘super-emitter’ activity occurs in every sector surveyed, with 10 per cent of point sources contributing roughly 60 per cent of point-source emissions—consistent with a study of the US Four Corners region that had a different sectoral mix9. The largest methane emitters in California are a subset of landfills, which exhibit persistent anomalous activity. Methane point-source emissions in California are dominated by landfills (41 per cent), followed by dairies (26 per cent) and the oil and gas sector (26 per cent). Our data have enabled the identification of the 0.2 per cent of California’s infrastructure that is responsible for these emissions. Sharing these data with collaborating infrastructure operators has led to the mitigation of anomalous methane-emission activity10.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Images from our survey of methane point emissions in California.
Fig. 2: The distribution of point-source emissions is consistent between two different regions.
Fig. 3: Independent airborne measurements of emissions from representative facilities on the basis of simultaneous flights or several visits.

Data availability

Radiance and reflectance products calibrated by AVIRIS-NG can be ordered from the AVIRIS-NG data portal at Retrieved methane images from flight lines in this study are available for download at Vista-CA infrastructure spatial layers are available for download at Images of methane plumes, Vista-CA layers and regional-scale methane-emission products for California can be viewed at Tables of methane plume and source characteristics are provided in the Supplementary Information.

Code availability

The custom computer code or algorithms used to generate the results in this study can be made available to researchers upon request.


  1. 1.

    California Senate Bill 1383. Short-Lived Climate Pollutants (2016).

  2. 2.

    Global Methane Initiative. (2019).

  3. 3.

    Zavala-Araiza, D. et al. Super-emitters in natural gas infrastructure are caused by abnormal process condition. Nat. Commun. 8, 14012 (2017).

    CAS  ADS  Article  Google Scholar 

  4. 4.

    National Academies of Sciences, Engineering, and Medicine. Improving Characterization of Anthropogenic Methane Emissions in the United States (National Academies Press, 2018).

  5. 5.

    Hamlin, L. et al. Imaging spectrometer science measurements for terrestrial ecology: AVIRIS and new developments. In IEEE Aerospace Conf. Proc. (2011).

  6. 6.

    Thorpe, A. K. et al. Airborne DOAS retrievals of methane, carbon dioxide, and water vapor concentrations at high spatial resolution: application to AVIRIS-NG. Remote Sens. Environ. 179, 104–115 (2016).

    ADS  Article  Google Scholar 

  7. 7.

    Thompson, D. R. et al. Real-time remote detection and measurement for airborne imaging spectroscopy: a case study with methane. Atmos. Meas. Tech. 8, 4383–4397 (2015).

    Article  Google Scholar 

  8. 8.

    California Greenhouse Gas Emission Inventory. Methane emissions for 2016. California Air Resources Board (2018).

  9. 9.

    Frankenberg, C. et al. Airborne methane remote measurements reveal heavy-tail flux distribution in Four Corners region. Proc. Natl Acad. Sci. USA 113, 9734–9739 (2016).

    CAS  ADS  Article  Google Scholar 

  10. 10.

    Photojournal. NASA instrument detects methane gas leak. Jet Propulsion Laboratory/California Institute of Technology (2018).

  11. 11.

    Wecht, K. J. et al. Spatially resolving methane emissions in California: constraints from the CalNex aircraft campaign and from present (GOSAT, TES) and future (TROPOMI, geostationary) satellite observations. Atmos. Chem. Phys. 14, 8173–8184 (2014).

    ADS  Article  Google Scholar 

  12. 12.

    Turner, A. J. et al. Estimating global and North American methane emissions with high spatial resolution using GOSAT satellite data. Atmos. Chem. Phys. 15, 7049–7069 (2015).

    CAS  ADS  Article  Google Scholar 

  13. 13.

    Jeong, S. et al. A multitower measurement network estimate of California’s methane emissions. J. Geophys. Res. Atmos. 118, 11339–11351 (2013).

    CAS  ADS  Article  Google Scholar 

  14. 14.

    Wong, C. K. et al. Monthly trends of methane emissions in Los Angeles from 2011 to 2015 inferred by CLARS-FTS observations. Atmos. Chem. Phys. 16, 13121–13130 (2016).

    CAS  ADS  Article  Google Scholar 

  15. 15.

    Jeong, S., Millstein, D. & Fischer, M. L. Spatially explicit methane emissions from petroleum production and the natural gas system in California. Environ. Sci. Technol. 48, 5982–5990 (2014).

    CAS  ADS  Article  Google Scholar 

  16. 16.

    Alvarez, R. et al. Reconciling divergent estimates of oil and gas methane emissions. Proc. Natl Acad. Sci. USA 112, 15597–15602 (2015).

    ADS  Article  Google Scholar 

  17. 17.

    Brandt, A. et al. Methane leaks from North American natural gas systems. Science 343, 733–735 (2014).

    CAS  ADS  Article  Google Scholar 

  18. 18.

    California Assembly Bill 1496. Methane emissions. (2016).

  19. 19.

    Saunois, M. et al. The global methane budget 2000–2012. Earth Syst. Sci. Data 8, 697–751 (2016).

    ADS  Article  Google Scholar 

  20. 20.

    Jeong, S. et al. Estimating methane emissions from biological and fossil-fuel sources in the San Francisco Bay Area. Geophys. Res. Lett. 44, 486–495 (2016).

    ADS  Article  Google Scholar 

  21. 21.

    Verhulst, K. R. et al. Carbon dioxide and methane measurements from the Los Angeles Megacity Carbon Project. Part 1: calibration, urban enhancements, and uncertainty estimates. Atmos. Chem. Phys. 17, 8313–8341 (2017).

    CAS  ADS  Article  Google Scholar 

  22. 22.

    Yadav, V. et al. Spatio-temporally resolved methane fluxes from the Los Angeles Megacity. J. Geophys. Res. Atmos. 124, 5131–5148 (2019).

    CAS  ADS  Article  Google Scholar 

  23. 23.

    Conley, S. et al. Methane emissions from the 2015 Aliso Canyon blowout in Los Angeles, CA. Science 351, 1317–1320 (2016).

    CAS  ADS  Article  Google Scholar 

  24. 24.

    Krautwurst, S. et al. Methane emissions from a Californian landfill, determined from airborne remote sensing and in situ measurements. Atmos. Meas. Tech. 10, 3429–3452 (2017).

    CAS  Article  Google Scholar 

  25. 25.

    Mouroulis, P. & Green, R. O. Review of high fidelity imaging spectrometer design for remote sensing. Opt. Eng. 57, 040901 (2018).

    ADS  Article  Google Scholar 

  26. 26.

    Thompson, D. R. et al. Space-based remote imaging spectroscopy of the Aliso Canyon CH4 superemitter. Geophys. Res. Lett. 43, 6571–6578 (2016).

    CAS  ADS  Article  Google Scholar 

  27. 27.

    Englander, J. G., Brandt, A. R., Conley, S., Lyon, D. R. & Jackson, R. B. Aerial interyear comparison and quantification of methane emissions persistence in the Bakken Formation of North Dakota, USA. Environ. Sci. Technol. 52, 8947–8953 (2018).

    CAS  ADS  Article  Google Scholar 

  28. 28.

    Greenhouse Gas Reporting Program (GRP). United States Environmental Protection Agency (2018).

  29. 29.

    Etminan, M., Myhre, G., Highwood, E. J. & Shine, K. P. Radiative forcing of carbon dioxide, methane, and nitrous oxide: a significant revision of the methane radiative forcing. Geophys. Res. Lett. 43, 12614–12623 (2016).

    CAS  ADS  Article  Google Scholar 

  30. 30.

    Jacob, D. J. et al. Satellite observations of atmospheric methane and their value for quantifying methane emissions. Atmos. Chem. Phys. 16, 14371–14396 (2016).

    CAS  ADS  Article  Google Scholar 

  31. 31.

    Methane Hotspots Research (AB1496). Airborne Facility-Level Methane Emissions Study California Air Resources Board (2018).

Download references


We thank the AVIRIS-NG team and Dynamic Aviation for their efforts in conducting the multiple airborne campaigns involved in this study, and our former colleague at the Jet Propulsion Laboratory (JPL), A. Aubrey, for early support in project planning. We acknowledge G. Franco (California Energy Commission, CEC) and E. Tseng (University of California Los Angeles) for comments on the paper. We appreciate the many discussions and input to flight planning and analysis from our colleagues at the California Air Resources Board (CARB), the Bay Area Air Quality Management District, the South Coast Air Quality Management District, the CEC, Southern California Gas Company, Sunshine Canyon Landfill Local Enforcement Agency, and the Milk Producer’s Council. We thank our colleagues at the Pacific Gas and Electric Company for their support for natural gas control release tests. We thank NASA’s Earth Science Division, particularly J. Kaye, for continued support of AVIRIS-NG methane science. Additional funding for data collection and analysis was provided to JPL by CARB under ARB-NASA Agreement 15RD028 Space Act Agreement 82-19863 and the CEC under CEC-500-15-004. The data from follow-up and contemporaneous Scientific Aviation flights used in this study were funded by CARB. Analysis of this work was also supported in part by NASA’s Carbon Monitoring System (CMS) Prototype Methane Monitoring System for California and the Advancing Collaborative Connections for Earth System Science (ACCESS) Methane Source Finder project. A portion of this research was carried out at the JPL, California Institute of Technology, under contract with NASA (NNN12AA01C). The authors are responsible for the content of the paper and the findings do not represent the views of the funding agencies.

Author information




R.M.D., A.K.T., F.M.H. and C.E.M conceived the study. R.M.D., A.K.T., F.M.H., T.R., I.B.M., M.L.E. and S.C. conducted flight planning. Each author contributed to the collection, analysis or assessment of one or more datasets necessary to perform this study. R.M.D., A.K.T., K.T.F., F.M.H. and T.R performed the analysis with contributions from B.D.B., D.R.T., C.F., N.K.C., M.F., J.D.H, B.E.C., R.O.G. and V.Y. R.M.D., A.K.T., K.T.F. and F.M.H. wrote the manuscript with input from all authors.

Corresponding author

Correspondence to Riley M. Duren.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Information file includes Materials and Methods, Supplementary Figs 1–14, Supplementary Tables 1–3, descriptions of Supplementary Tables 4 and 5, and additional references.

Supplementary Table 4

Methane plume list.

Supplementary Table 5

Methane source list.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Duren, R.M., Thorpe, A.K., Foster, K.T. et al. California’s methane super-emitters. Nature 575, 180–184 (2019).

Download citation

Further reading


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

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

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