Responses in the growth of the northern forest biomes to a CO{sub 2}-induced climatic change, as evaluated by the Frankfurt Biosphere Model (FBM)

The Frankfurt Biosphere Model (FBM), a mechanistic and prognostic compartment model of the terrestrial biosphere, has been developed to simulate the carbon exchange fluxes between the vegetation and the atmosphere with a spatial resolution of 0.5{degree} x 0.5{degree} on a global scale. In this contribution the authors use the FBM to assess the possible changes in the response of the northern forest biomes under a future 2{times}CO{sub 2} climate. The development of these ecosystems from its initial seedling state to its climax state is simulated under different climatic conditions. The 2{times}CO{sub 2} climate for these simulations was provided by the GCM of the MPI fuer Meteorologie in Hamburg (ECHAM). The differences in vegetation growth under contemporary and future climate can be assessed by performing three model runs with the same parameterization but with different driving climatic variables for each vegetation type and location: (1) a simulation run with present climate conditions; (2) a simulation run under 2{times}CO{sub 2} climate conditions; and (3) which is same as (2) but with the assumption of a CO{sub 2} fertilization effect.