Can we explain atmospheric carbon dioxide oscillations during the past 400,000 years?

The aim of this paper is to explain observed correlations between temperature and carbon dioxide concentrations in Antarctic ices. Chemical characteristics of the carbonate system, biological and calcium carbonate pumps between superficial and deep ocean, CCD and lysocline allow a satisfactory representation of the present ocean. Sediment studies show that the biological pump was more efficient in glacial times and that the lysocline was at about the same depth. It is then possible to reconstruct the carbonate system at this period. The question is then to identify the processes involved in the carbonate system change: increase of deep phosphate concentration, decrease of coral reefs, increased competition of siliceous organisms versus calcareous ones, input of iron-rich dust in Southern ocean. None of these propositions allows a satisfactory explanation.