Ruddiman (2003, 2005) considers that CO2 and CH4 concentrations would have declined during the Holocene in absence of land management and wetlands cultures that, according to him, perturbed the chemical composition of the atmosphere as early as 6000 years ago. Experiments with a general circulation model suggest that this natural scenario would have led to glacial inception (Ruddiman et al., 2005). Experiments with climate-ice sheet models (Claussen et al., 2005; Crucifix et al., 2005) are less conclusive, but in the latter the suggested draw-down in methane concentration was admittedly neglected.

Was this article helpful?

0 0

Post a comment