WIT Press

Modelling Greenhouse Effect: An Ecodynamic Approach


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F. M. Pulselli, E. B. P. Tiezzi & R. M. Pulselli


The model described in this paper can be defined with the neologism \“ecodynamic”. The biosphere is defined as the geometric locus in which entropy decreases. The biosphere is in a steady state: it does not grow quantitatively but only in biodiversity (or at least is has grown in biodiversity from the origin of life up to recent millennia). Since the exchange of matter with the outside is practically negligible and, on the other hand, the Earth receives an enormous flux of energy from outside, the biosphere can be regarded thermodynamically as a closed system. The ''conditio sine qua non'' for all this to continue is the absence of an adiabatic membrane around the planet. In other words, the greenhouse effect must not be allowed to prevent the flow of positive entropy into space. The role of carbon dioxide and other "greenhouse" gases becomes determinant in this ecodynamic model, one reason being the great difference between the biological time of fossil formation and the fleeting historical time in which the fossils are being used. The space of the biosphere is defined as the spherical corona of the planet including the atmosphere and the ozonosphere, the oceans and the Earth's crust, but not reduced carbon which has effectively been treated as a waste by nature, relegated as it is to the bowels of the Earth, the biological dustbin. If we examine the spatial model in more detail, we find that the boundary between the biosphere and the universe is open to the entry of flows of energy and matter. It receives more than 1024 joules of solar energy per year, an enormous quantity, and receives practically no matter, with the exception of