How does the earth system generate and maintain thermodynamic disequilibrium and what does it imply for the future of the planet?
Author: | Environment
[Abstract] The chemical composition of the earth’s atmosphere far from equilibrium is unique in the solar system and has been attributed to the presence of widespread life. Here I show that this perspective can be quantified using non-equilibrium thermodynamics. Generating disequilibrium in a thermodynamic variable requires the extraction of power from another thermodynamic gradient, and the second law of thermodynamics imposes fundamental limits on how much power can be extracted. When applied to complex earth system processes, where several irreversible processes compete to deplete the same gradients, it is easily shown that the maximum thermodynamic efficiency is much less than the classic Carnot limit, so that the ability of the earth system to generate power and disequilibrium is limited. This approach is used to quantify how much free energy is generated by various earth system processes to generate chemical disequilibrium. It is shown that surface life generates orders of magnitude more chemical free energy than any abiotic surface process, therefore being the primary driving force for shaping the geochemical environment at the planetary scale. To apply this perspective to the possible future of the planet, we first note that the free energy consumption by human activity is a considerable term in the free energy budget of the planet, and that global changes are closely related to this consumption of free energy. Since human activity and demands for free energy are going to increase in the future, the central question is how human free energy demands can increase sustainably without negatively impacting the ability of the earth system to generate free energy. I illustrate the implications of this thermodynamic perspective by discussing the forms of renewable energy and planetary engineering that would enhance overall free energy generation and thereby “empower” the future of the planet.
(Submitted on 10 Mar 2011 to Philosophical Transactions of the Royal Society A)
This material is the work of the author(s) indicated. Any opinions expressed in it are not necessarily those of National Wind Watch.
The copyright of this material resides with the author(s). As part of its noncommercial effort to present the environmental, social, scientific, and economic issues of large-scale wind power development to a global audience seeking such information, National Wind Watch endeavors to observe “fair use” as provided for in section 107 of U.S. Copyright Law and similar “fair dealing” provisions of the copyright laws of other nations. Send queries to query/wind-watch.org.
|Wind Watch relies entirely
on User Funding