Resolving a longstanding climate enigma
The global carbon cycle is a complex process involving the biosphere, atmosphere and oceans. Improving our understanding of the fluxes of carbon between these reservoirs will help improve efforts to model the future climate. NOCES, a research project funded by the Fifth Framework Programme, included modelling experts from the Max Planck Institute for Meteorology (MPI-M). Building on the results of previous EU-funded studies, MPI-M examined the mechanisms associated with carbon take-up and transport by oceans and the uncertainty associated with these mechanisms. During NOCES MPI-M integrated separate models for the biosphere, atmosphere and oceans. Their most important accomplishment involved resolving a longstanding failure of previous models to accurately simulate oceanic carbon transport in the pre-industrial era. The key was to account for iron limitation in primary production in the Southern Ocean. This creates a strong carbon gradient that results in flux of nearly one Petagram (one billion tonnes) of carbon from the Northern to the Southern Hemisphere annually. A complete description of the models used, the simulation results and their interpretation can be found in a relevant PhD thesis at MPI-M.