**5. Homeostasis in ecological systems, and the need to keep the Earth system cool**

The conventional thermodynamics was formulated in the 19th century under the orthodoxy of the foundationalist mechanical-philosophy, in which the world is a machine made of machines. The theory is unable to deal with systems, especially ecological systems made of biological organisms.

Because the conventional theory is based on metaphysics of physical necessity, in dealing with complex systems with emergent orders a common theory of complex systems is known as maximum entropy production principle (MEPP). MEPP accounts for the emergence of local orders of individual complex systems by individual complex systems' ability to export entropy produced (grown) internally/ locally to their surroundings. In the context of the Earth and ecological systems on Earth, such conclusion would predict an Earth ecosystem with greater and greater entropy corresponding with higher and higher global disorder.

A living organism becomes a dead organism by definition if its existence approaches a state of thermodynamic equilibrium or it exists in an environment that is approaching thermodynamic equilibrium. Because of that, a living organism as well as any complex system consisting of living organisms can only exist at states safely away from equilibrium. Aside from a metric-set of homeostatic ranges (for instance, temperature range), "far from equilibrium existence" (its metric is the entropy difference between entropy of the existing system and entropy of the system when it would approach thermodynamic equilibrium) is another defining characteristic of the *homeostatic state* of an organism. That is,

*homeostatic state = metric-set of homeostatic ranges*, and *entropy difference of the system from system-at-reference-equilibrium-state.*

It is the latter defining characteristic that disqualifies MEPP, though it may be valid for complex physical systems such as climatic systems, for explaining the emergence of biological orders [19]. MEPP is a theory that is in full compliance with metaphysics of physical necessity. Ref. [17] puts forwards that by admitting causal necessity, the inference that the inevitability of entropy growth leads to the inevitable accumulation of heat, which is accepted and embraced by MEPP, is broken. Correspondingly, Ref. [19] puts forwards the thesis that emergence of biological and ecological orders requires admitting causal necessity as well. That is, the abandonment of mechanical-philosophy with its physical necessity stricture.

An example of this kind of consideration is the body of work on Gaia by James Lovelock, who applied far-from-equilibrium consideration to complex system consisting of living organisms. When he was a consultant at the Jet Propulsion Laboratory in Pasadena, CA, he was given the assignment of how to detect whether a planet harbors life. Lovelock began with the hypothesis that a planet as a complex system consisting of life—like a single organism—must be far from equilibrium or at radically disequilibrium state. Therefore, its atmospheric chemical composition must exhibit high concentrations of reactive gases, such as Earth's atmosphere which contains high concentration of oxygen and methane. Whereas, the static Martian atmosphere composing of almost entirely of non-reactive carbon dioxide is indicative of it being absent of life. Lovelock then took the next step by hypothesizing the "renewing" of these reactive gases to be a self-regulating mechanism of a planetary ecosystem. Lovelock together with microbiologist Lynn Margulis went further claiming the Earth to be in effect a superorganism, called Gaia (Lovelock, [20], Lovelock and Margulis, [21, 22]; Margulis and Lovelock, [23]). This version of Gaia, of a "living" complex system consisting of living organisms just like a single

living organism, had received strong push back, when it was originally proposed, by biologists especially evolutionary biologists as unworkable in theory (Dawkins, [24]; Doolittle, [25]).

However, the idea of Gaia that all living things collectively define and maintain the conditions conducive for life through a filtering "selection" mechanism has since begun to receive acceptance [26] including Doolittle himself (see below). What is at issue is not the disequilibrium state of the Earth and that some kind of self-regulating mechanism for maintaining the state homeostatically (the former is a matter of physics and the latter is an observational fact of the Earth system), but how a "superorganism" acquires such a mechanism. Doolittle, in his reassessment of Gaia, put the matter this way (very different from his view of four decades earlier) as:

*The Gaia hypothesis in a strong and frequently criticized form assumes that global homeostatic mechanisms have evolved by natural selection favoring the maintenance of conditions suitable for life. Traditional neoDarwinists hold this to be impossible in theory. But the hypothesis does make sense if one treats the clade that comprises the biological component of Gaia as an individual and allows differential persistence – as well as differential reproduction – to be an outcome of evolution by natural selection. Recent developments in theoretical and experimental evolutionary biology may justify both maneuvers [27].*

This new assessment on Gaia is a momentous step, which confirms the rejection of mechanical-philosophy—additionally, it makes the metaphysical presupposition that the world is made up of *natural kinds* such as atoms, molecules, and chemical elements, and *individuals* such as organisms, species. Clades, and Gaia. Whereas the former is characterized in terms of physical necessity, the latter in terms of physical necessity and causal necessity. The concept of natural selection was the revolutionary step taken by Darwin to finesse the teleological issue within the orthodoxy of mechanical-philosophy in biology. That was revolutionary and subversive. With the new momentous step, natural selection, which seemed to be a poster-boy of mechanical-philosophy, now undergoes its subversive transformation overthrowing the mechanical philosophy to include "survival of reproduction competitiveness" as well as "persistence as a result of global homeostatic mechanisms" [27].

One of Earth's homeostatic mechanisms is the mechanism to keep the Earth cool, according to Lovelock, in face of Sun's increasing solar radiative heat output. It is necessary to keep the Earth cool because:

*It is vital for our survival that the sea is kept cool …Whenever the surface temperature of the ocean rises above 15°C, the ocean becomes a desert far more bereft of life than the Sahara. This is because at temperature above about 15°C the nutrients in the ocean surface are rapidly eaten and the dead bodies and detritus sink to the regions below. There is plenty of food in the lower waters, but it cannot rise to the surface because the cooler lower ocean water is denser than water at the surface … This is important because … Earth is a water planet with nearly three-quarters of its surface covered by oceans. Life on land depends on the supply of certain essential elements such as sulfur, selenium, iodine and others. Just now these are supplied by ocean surface life as gases like dimethyl sulfide and methyl iodide. The loss of this surface life due to the heating of these waters would be catastrophic [28].*

Rising ocean surface temperature will lead to catastrophic decline of both ocean surface life and land life.

How has Gaia, the Earth system, maintained its temperature within a homeostatic range: Lovelock suggests the following mechanism as a working hypothesis: *"In modern times, carbon dioxide is a mere trace gas in the atmosphere compared with its dominance on the other terrestrial planets or with the abundant gases of Earth, oxygen and nitrogen. Carbon dioxide is at a bare 340 parts per million by volume now. The early Earth when life began is likely to have 1000 times as much carbon dioxide … As the Sun warmed, two processes took place. The first was an increase in the rate of evaporation of water from the sea and, hence, rainfall; the second, an increase in the rate of the reaction of carbon dioxide with the rocks. Together, these processes would increase the rate of weathering of the rocks and so decrease the carbon dioxide. The net effect would be a negative feedback on the temperature rise as the solar output increased … [Lovelock then added a third process involving living organisms] … living organisms act like a giant pump. They continuously remove carbon dioxide from the air and conduct it deep into the soil where it can react with the rock particles and be removed [29].*

*" … If confirmed, it suggests that cloud cover and low carbon dioxide operated in synchrony as part of a geo-physiological process to keep the Earth cool … [30]. "From the very beginning of life on Earth, carbon dioxide has had a contradictory role. It is the food of photo-synthesizers and therefore of all life; the medium through which the energy of sunlight is transformed into living matter. At the same time, it has served as the blanket that kept the Earth warm when the Sun was cool. A blanket that, now that the Sun is hot, is becoming thin; yet one that must be worn, for it is also our sustenance as food. We have seen earlier how the biota everywhere on the land and sea are acting to pump carbon dioxide from the air so that the carbon dioxide which leaks into the atmosphere from volcanoes does not smother us. Without this never-ceasing pumping, the gas would rise in concentration within a million years to levels that would make the Earth a torrid place and unfit for almost all life here now. Carbon dioxide is like salt. We cannot live without it, but too much is a poison" [31].*

The details of the working hypothesis may yet to be worked out. But two takeaways are sufficiently clear and they are: (Surmise-1) the necessity to keep the Earth system cool in order to keep it within the temperature *homeostatic ranges* while keeping in mind of other important *homeostatic ranges* of the *metric-set*; (Surmise-2) carbon dioxide is the critical element involved in the mechanisms of achieving the goal.

This brings us to the two metrics of *homeostatic state*, i.e., underlying all the homeostatic ranges of Surmise-1 is the idea of keeping the Earth system safely from thermodynamic equilibrium—corresponding to Surmise-2, in which carbon dioxide is the proxy of *entropy difference of the system from system-at-reference-equilibriumstate*. This is why it is necessary to abandon the conventional thermodynamics, in which the idea would be a nonstarter, to embracing, instead, a new engineeringthermodynamics. Only with the second law as both a principle of inevitable entropy growth and a principle of entropy growth potential, it is possible to keep the Earth system safely from thermodynamic equilibrium.

One example of solutions for the goal is the electrification of space heating. The purpose of the essay is not to outline such kind of specific solutions but to use such a solution-example to advance the argument that such opportunities exist only if we frame the crisis and problem in systems-framework in terms of EGP management.

In this systems-thinking framework, we do have an existential threat. The threat is, however, not the threat of running out of fossil fuel or fossil energy. The standard narrative of such kind of thinking is that we have abundant solar energy and the solution to our problem is to find ways of converting a small part of solar energy (including wind energy) into useful energy. This is clearly the wrong way to look at the problem. If sunlight is our savior (which is) in this sense, a warming Sun *Systems-Thinking Framework for Renewables-Powered World DOI: http://dx.doi.org/10.5772/intechopen.100438*

should have been a welcoming development, in opposite to the idea of *heat threat* from a hot Sun [32].

Transition from fossil energy to renewables *is* a good idea, not because we welcome a warming Sun as a source of heat energy. But because the solar output received by Earth is a "form of entropy flow of very low value." Assuming the Earth system is in a state of energy balance, the Earth infrared radiative heat outflow equals the solar radiative heat inflow received by the Earth. The corresponding values of entropy flow received by the Earth from the Sun and of entropy out-flow from the Earth to outspace will be significantly very low and very high, respectively. That means that very large entropy growth potential exists in the difference of the two flows.

That means that large opportunities exist in the management of entropy growth potential. Some of those opportunities, such as electrification of heating, can be related to the control of carbon dioxide. That also means that while a warming Sun poses heat threat to the Earth, it also presents greater opportunities for EGP management.
