Natural CH 4 gas seeps in the French Alps: characteristics, typology and contribution to CH 4 natural emissions to the atmosphere

Frédérick Gal (1) , Wolfram Kloppmann (1) , Eric Proust (1) , Gaëtan Bentivegna (1) , Pierrick Défossez (1) , Bernard Mayer (2) , Eric C. Gaucher (3)

1 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
2 University of Calgary
3 CSTJF - Centre scientifique et Technique Jean Feger

Quantification of greenhouse gases that naturally leak into the atmosphere has to be considered in lien with mitigation of CO 2 emissions, underground storage of CO 2 and conventional and unconventional gas exploitation. Among the long lived greenhouse gases, methane is one of the most critical specie regarding its global warming potential, far greater than the one of CO 2. Methane can be released in the atmosphere through human activities (agricultural practices, landfills) but it can also be released from natural processes occurring e.g. in wetlands. Another source is constituted by natural gas seeps existing all over the world. Their contribution has been quantified in Europe to account for about a third of the yearly methane emissions (Etiope, 2009, Atmospheric Environment 43, 1430-1443). The global methane budget still needs completion and refining, taking into account undocumented macro-seeps and, in particular, micro-seeps, difficult to measure and to account for. Such unreported seeps are located in the French Alps, near Grenoble. Although some of these emanations are known since Roman times, they have not been investigated since, except in the early XX

Domains: Earth Sciences

Frédérick Gal, Wolfram Kloppmann, Eric Proust, Gaëtan Bentivegna, Pierrick Défossez, et al.. Natural CH 4 gas seeps in the French Alps: characteristics, typology and contribution to CH 4 natural emissions to the atmosphere. 13th International Conference on Greenhouse Gas Control Technologies, GHGT-13, Nov 2016, Lausanne, Switzerland. ⟨hal-01325608⟩