Biomass burning, carbon isotope

Concerns over atmospheric methane as a greenhouse gas and the large contribution of biomethanogenesis as a source of this gas make it important to determine the relative significance of various components of this activity. A recent paper (8) summarized estimates (28-30) of source fluxes of atmospheric methane based on several carbon isotopic studies and presented new data on natural sources and biomass burning. These data (Table III) show that of a total flux of 594 million tons (Tg) per year, 83% is produced via biomethanogenesis from a combination of natural (42%) and anthropogenic (41%) sources. 

Schmidt, M. W. I., Skjemstad, J. O., and Jager, C. (2002). Carbon isotope geochemistry and nanomorphology of soil black carbon Black chernozemic soils in central Europe originate from ancient biomass burning, Global Biogeochem. Cycles 16, Art. No. 1123. 

Quay, P.D., S.L. King, J. Stutsman, D.O. Wilbur, L.P. Steele, I. Fung, R.H. Gammon, T.A. Brown, G.W. Farwell, P.M. Grootes, and F.H. Schmidt, Carbon isotopic composition of atmospheric CH4 Fossil and biomass burning source strengths. Global... 

Ballentine D. B., Macro S. A. and Turekian V. C. (1988) Variability of stable carbon isotopic compositions in individual fatty acids from combustion of C4 and C3 plants implications for biomass burning. Chem. Geol. 152, 151-161. 

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