Processes for constant energy conversion are the basis of any life. Predominant are still the oxidation processes. Of special significance is the natural O2/CO2 cycle, named after the Nobel prize winner in 1961. M. Calvin. The drastically increasing oxygen consumption in all areas of life - especially in the industrial sector - and the simultaneously rising CO2 concentration in the atmosphere threaten to lead for future penetrations to interferences (at least regionally) in the ecological equilibrium. In the meantime, in general growing importance is attached to the recycling processes in the direction of a ＇＇substainable development＇＇. According to the present state of knowledge, prospects and effective counter-measures are presented.