Simulation results from a coupled model of carbon dioxide and methane global cycles

•A combined model CO2 and CH4 interprets major natural and man-made climate changes.•A reduction in global forests by 0.45%/year will result in 552.5 ppmv CO2 at 2150.•The dynamics of atmospheric CO2 for various scenarios of changing land cover areas.

The problem of greenhouse effect due to the anthropogenic influence on the global cycles of greenhouse gases is discussed extensively in the scientific literature. This paper aims to contribute solving this problem by presenting the simulation results of a new model of combined carbon and methane biogeochemical cycles considering the spatial structure of their sources and sinks on a global scale. All reservoirs and fluxes of the carbon and methane that are taken into consideration in the model have different temporal scales, while the spatial scale for sources and sinks of carbon and methane on the land is considered as 4° by latitude and 5° by longitude. The World Ocean is parameterized by two-point models with four levels in depth with a separation between pelagic and upwelling zones. In addition, the interaction between the atmosphere and carbon reservoirs on the land and in the ocean includes the processes of photosynthesis, decomposition, respiration and burning. The global cycle of methane in the atmosphere-hydrosphere-land system is described by the scheme that takes into account the potential of the radiation fluxes, which is a function of time. Furthermore, the structure of the model used for the coupling of the carbon and methane cycles consists of 12 blocks, which carry out basic calculation procedures for their fluxes. Finally, the results of simulation experiments are discussed considering scenarios for changes in forest areas, showing their significant role in the climate change issue.