The glacial record has shown that atmospheric methane concentrations have fluctuated in the past, particularly during the Bolling-Allerod interstadial. We used an inverse photochemical carbon-cycle model to interpret the magnitude of effect that glacial-interglacial atmospheric methane variations have on the global carbon cycle. The results of this modelling suggest that an observed variation in atmospheric C-14 during this time period may be the result of oxidation of the increased atmospheric methane. We re-examine methane clathrate in palaeosols as a potential source of the methane, and the influence of deglaciation and subsequent heat transport from advecting groundwater in these sediments may be a plausible mechanism by which atmospheric CH4 concentrations abruptly increased during the Bolling-Allerod.
- carbon cycle
- atmospheric composition