The incompatibility of ice-core CO₂ data with reconstructions of biotic CO₂ sources (II).

Abstract

The compatibility of ice-core CO₂ data with direct estimates of biotic CO₂ release is tested using a response function analysis that, apart from stationarity, leaves the oceanic uptake of CO₂ largely unconstrained. The role of CO₂-enhanced growth (which had not been considered in an earlier study of this type) is examined explicitly. It is found that allowing for CO₂-enhanced growth increases the discrepancy between the source estimates and the ice-core data. The proposed explanation is that some of the early increase in CO₂ concentrations reflects a recovery from a perturbation associated with the little ice-age.