Sunday, March 3, 2024

Life and Thermodynamics (and topsoil and baths)

From Lapham's Quarterly Energy issue:

Taxes Due:  William Ophuls mines the topsoil.

The laws of thermodynamics, among the most basic known to science, constitute a natural tyranny against which resistance is useless. They guarantee that the human “conquest” of nature is, and always will be, a Pyrrhic victory. But what are these laws that so decisively set aside the human pretension to technological dominance?

The first law states that energy is always conserved. It can change form, but it can neither be created nor destroyed. However, the second law states that entropy tends to increase (where entropy is a measure of chaos, randomness, and disorder). Energy tends to decay into less and less useful forms. There may be just as much total energy after the transformation as before, but the quality of that energy will be poorer.

In their purest scientific form, the laws of thermodynamics are concerned with energy as heat and do not seem at first glance to have much to do with daily life. In fact, they govern every aspect of the natural and human economies. 

One way of restating the second law, often called the entropy law, is to say that matter-­energy transformations cannot be reversed; time’s arrow flies in only one direction. When Humpty Dumpty takes his great fall, all the king’s horses and all the king’s men can never put him together again. His material “energy” has been irretrievably lost. Similarly, when ice melts in a glass of lemonade, the cold “energy” stored in the ice cubes dissipates into the environment, never to be recaptured. Vice versa for hot objects. Our sun is slowly but surely radiating away its concentrated energy. Approximately five billion years from now, it will exhaust its fuel and eventually fade into a dim ember.

Civilization expedites entropy. Agricultural production is the foundation of civilized life. But the word production is a misnomer. What humans actually do is mine the topsoil. The product is food for human consumption—but the by-product is erosion, compaction, leaching, and other damage to the soil’s vitality and integrity. The nutrients in the food are not usually returned to the land but excreted into latrines and sewers, whence they are dispersed into rivers, lakes, and oceans, never to be recaptured except in the negative form of pollution. 

Over the centuries, farmers have learned to counteract the worst entropic consequences of agriculture by various means: crop rotation, fallowing, terracing, manuring, and the like. These measures do indeed slow down the losses. Given favorable circumstances, it is possible to construct systems of sustainable agriculture that keep entropic losses to a bare minimum. Such systems are necessarily labor-intensive and scrupulously conservative—more like horticulture than our usual notion of agriculture. 

In most cases, however, conditions are not favorable. Since the land in its natural state is incapable of meeting increased demand, external energy must be applied to boost yields artificially. This development reaches its apex in industrialized agriculture, which is a biological machine that turns petroleum into calories at a ratio of approximately ten to one. In other words, the entropic price of modern man’s bowl of porridge is the degradation of at least ten times as much energy as is contained in the bowl itself.

Or take one of the great inventions of civilization: the bath. Whether it was the Roman thermae, the Arab hammam, or the traditional Japanese furo, it was heated with wood. But in the process most of the energy in the wood was wasted. That is, it turned into smoke, ashes, and heat—some of which did the work of making hot water, but most of which escaped up the chimney. And even the useful heat in the bathwater was soon dissipated into the atmosphere, just like the cold in the glass of lemonade. In addition, it took matter and energy to build the baths in the first place and to maintain them thereafter (not to mention aqueducts, roads, and other supportive infrastructure)....

....MUCH MORE