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Global Inventory of Fossil and Non-fossil Methane δ13C Source Signature Measurements for Improved Atmospheric Modeling


  • Sherwood, O.A., University of Colorado/INSTAAR
  • Schwietzke, S., University of Colorado/CIRES, NOAA/ESRL/GMD
  • Arling, V.A., University of Colorado/CIRES, NOAA/ESRL/GMD
  • Etiope, G., Istituto Nazionale di Geofisica e Vulcanologia


Studies of the global methane (CH4) budget (including 3D inversion and box model studies) frequently include measurements of atmospheric δ13C-CH4 as an additional constraint for better allocation of different natural and anthropogenic CH4 sources, and this requires information about the δ13C isotopic signature (δ13CSource) of the different CH4 sources. The δ13CSource measurement sample sizes used in published global CH4 budgets are either small or unknown, uncertainties are rarely applied, and global representativeness is lacking. We have compiled the most comprehensive δ13CSource database to date including 8,128 original measurements from fossil fuels (FF; 7,482 conventional and 646 shale gas samples) and 2,068 original measurements from microbial and biomass burning sources, which can be used to define globally-weighted average δ13CSource with well defined uncertainties. This database shows that previously used global average δ13CSource are outdated, and particularly FF signatures are significantly lighter than canonical values.

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This database is made freely available to the scientific community and is intended to stimulate and support global methane cycle and other modeling studies. We rely on the ethics and integrity of the user to assure that the authors receive fair credit for their work. Fair credit will depend on the nature of the work and the requirements of the institutions involved. Your use of this database implies an agreement to contact the database co-authors to discuss the nature of the work and the appropriate level of acknowledgement. If the database is essential to the work, or if an important result or conclusion depends on the database, co-authorship may be appropriate. This should be discussed with the data providers at an early stage in the work. Contacting the data providers is not optional; if you use the database, you must contact the data providers. A co-author email distribution list is provided during the database download process, which generates an automated e-mail to the user containing all relevant information.

Required Citation

The database has a Digital Object Identifier (DOI) registered with the International DOI Foundation. In addition to the conditions of fair use as stated above, users must also include the following database citation in any publication or presentation using the product:

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

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Global d13C CH4 source signature inventory

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