The emission and concentration of CO 2 is linked to an ocean module and a terrestrial biota module, together reflecting the C-cycle. The removal of the trace gases concerned by atmospheric chemical processes is an essential feature. Spatial dimension of the simulated trace gas concentration is zero. The calculated trace gas concentrations serve as an input for the climate module. The simulation model is a reflection of the current state of knowledge.
Current knowledge being far from complete, the model has structural limitations.
Scenarios for future trace gas emissions, as presented in this paper, are only indicative, while sources are not fully known or quantified. Positive feedback on microbiological emissions of trace gases by temperature rises is not yet taken into account.