Exergy consumption and entropy generation rates of earth: an assessment for the planet and its primary systems

Abstract

Although energy is conventionally examined when studying thermodynamic flows and balances for the Earth and its systems, the planet does not consume energy as its energy inflows and outflows are in balance. Similarly, energy is conserved for systems on the Earth. The Earth does, however, consume exergy and generate entropy, and it is insightful to examine the thermodynamics of the Earth in terms of exergy, or the related quantity entropy. These perspectives are considered here for the Earth and its main systems: the biosphere, people and civilization. The work provides an enhanced understanding of the type, location and causes of thermodynamic losses for the Earth as well as its main systems and subsystems, and of the connections and relations between the Earth and its biosphere, as well as civilization and people. It is observed for the year 2019 that civilization uses exergy to create many products and services and that the exergy consumption rate of the Earth's biosphere is approximately five times larger than that of civilization and 100 times larger than that of people as individuals. Also, the solar exergy rate provides the Earth with a very large exergy input rate, about 10,000 times greater than the needs.