Energy budget of the biosphere and civilization: Rethinking environmental security of global renewable and non-renewable resources

How much and what kind of energy should the civilization consume, if one aims at preserving global stability of the environment and climate? Here we quantify and compare the major types of energy fluxes in the biosphere and civilization. It is shown that the environmental impact of the civilization consists, in terms of energy, of two major components: the power of direct energy consumption (around 15 X 1012 W, mostly fossil fuel burning) and the primary productivity power of global ecosystems that are disturbed by anthropogenic activities. This second, conventionally unaccounted, power component exceeds the first one by at least several times. It is commonly assumed that the environmental stability can be preserved if one manages to switch to clean, pollution-free energy resources, with no change in, or even increasing, the total energy consumption rate of the civilization. Such an approach ignores the fact that the environmental stability is regionally and globally controlled by the functioning of natural ecosystems on land and in the ocean. This means that the climate and environment can only remain stable if the anthropogenic pressure on natural ecosystems is diminished, which is unachievable without reducing the global rate of energy consumption. if the modem rate of anthropogenic pressure on the ecosystems is sustained, it will be impossible to mitigate the degradation of climate and environment even after changing completely to clean technologies (e.g., to the zero emissions scenario). It is shown that under the limitation of preserving environmental stability, the available renewable energy resources (river hydropower, wind power, tidal power, solar power, power of the thermohaline circulation, etc.) can in total ensure no more than one tenth of the modern energy consumption rate of the civilization, not to compromise the delivery of life-important ecosystem services by the biosphere to the humanity. With understanding still lacking globally that the anthropogenic impact on the biosphere must be strictly limited, the potential availability of the practically infinite stores of nuclear fusion energy (or any other infinite energy sources) poses an unprecedented threat to the existence of civilization and life on the planet. (C) 2008 Published by Elsevier B.V.