Scarcity of exergy and ecological evaluation based on embodied exergy

The driving force of the earth system is shown to be the cosmic exergy due to radiational difference between the sun and the cosmic background, instead of the solar energy. The scarcity of cosmic exergy availability as the fundamental natural resource for the ecosphere and the human society is revealed by a systematic study on the global consumption of the cosmic exergy in the earth and a budget of the exergy consumption with respect to main terrestrial processes. A conceptual framework or ecological evaluation is developed on the basis of a new concept referred to as embodied exergy in terms of the cosmic exergy consumed directly or indirectly in making or sustaining a general commodity as a product, service or an emission. As a generalization of Szargut's cumulative exergy consumption in resource analysis, embodied exergy is chosen, in place of embodied energy, to define Odum's emergy. Concrete calculation schemes for embodied exergy accounting are provided as a systematic revision and rephrasing of existing embodied emergy analysis. ? 2004 Elsevier B.V. All rights reserved.EI04531-5521