Energy In World History

Vaclav Smil

• Éditeur: Routledge
• Année: 2019
• ISBN:
  9780429720123
• Édition: 1
• Sujet: Historia
• Sous-sujet: Historia del mundo

Every human activity entails the conversion of energy. Changes in the fundamental sources of energy, and in the use of energy sources, are a basic dimension of the evolution of society. Our appreciation of the significance of these processes is essential to a fuller understanding of world history. Vaclav Smil offers a comprehensive look at the role

1
Energy and Society

Obviously, if we can find a single word to represent an idea which applies to every element in our existence in a way that makes us feel we have a genuine grasp of it, we have achieved something economical and powerful. This is what has happened with the idea expressed by the word energy. No other concept has so unified our understanding of experience.

—R. Bruce Lindsay, Energy (1975)

ENERGY IS THE ONLY universal currency: It must be transformed to get anything done. Manifestations of these transformations in the physical universe range from rotating galaxies to the erosive forces of tiny raindrops. Life on Earth, the only known life in the universe, would be impossible without the photosynthetic conversion of solar energy into plant biomass. Humans depend on this transformation for their survival and on many more energy flows for their civilized existence.

The evolution of human societies has been dependent upon the conversion of ever larger amounts of ever more concentrated and more versatile forms of energy. From the perspective of natural science, both prehistoric human evolution and the course of history may be seen fundamentally as the quest for controlling greater energy stores and flows. This endeavor has brought about the expansion of human populations and allowed for increasingly complex social and productive arrangements. Neither the growth of technical capabilities and a deeper understanding of the surrounding world nor the effort to secure a better quality of life would have been successful without innovations in energy use.

As formulated by Alfred Lotka (1925) in his law of maximum energy, natural selection will tend to increase the total mass of an organic system, and this will increase the rate of circulation of matter as well as the total energy flux through the system—as long as there is a surplus of available energy. The history of successive civilizations, the largest and most complex organisms in the biosphere, has followed this course. Human dependence on ever higher energy flows can be seen as an inevitable continuation of organismic evolution.

Starting with Wilhelm Ostwald (1909), a Nobel prize-winning chemist, twentieth-century scholars have repeatedly made the link between energy and civilization. Two quotations will suffice to illustrate this relationship. In a pioneering paper, anthropologist Leslie White (1943) called the link the first important law of cultural development: "Other things being equal, the degree of cultural development varies directly as the amount of energy per capita per year harnessed and put to work" (p. 338). Two generations later, a physicist, Ronald E. Fox (1988), concluded a book on energy in evolution by writing, "A refinement in cultural mechanisms has occurred with every refinement of energy flux coupling" (p. 166). Assessing the validity of such conclusions is a major goal of this book.

But even Nobel prize winners encounter great difficulties when they try to give a satisfactory answer to a seemingly simple question: What is energy? Richard Feynman (1988), one of the greatest physicists of the twentieth century, stressed, "It is important to realize that in physics today, we have no knowledge of what energy is. We do not have a picture that energy comes in little blobs of a definite amount" (p. 4-2). What we do know is that all matter is energy at rest, that energy manifests itself in a multitude of ways, and that these distinct energy forms are linked by numerous conversions (see Figure 1.1). Scientists rapidly expanded and systematized their understanding of these stores, potentials, and transformations during the nineteenth century and perfected it during the twentieth; surprisingly, they discovered how to release nuclear energy in the late 1930s, two decades before they understood how photosynthesis works.

Flows, Stores, and Controls

The availability of power sources determines the amount of work activity that can exist, and control of these power flows determines the power in man's affairs and in his relative influence on nature.

—Howard T. Odum, Environment, Power, and Society (1971)

All known forms of energy are critical for human existence. This reality precludes any rank-ordering of their importance. Much in the course of history has been determined and circumscribed by universal and planetary flows of energy and their regional or local manifestations. Fundamental features of the universe are governed by gravitational energy, which orders countless galaxies and star sets akin to our solar system. Gravity also keeps our planet orbiting at just the right distance from the sun and holds the atmosphere, which makes the Earth habitable (see A1.1).

Like all active stars, the sun is powered by nuclear energy. The product of those thermonuclear reactions reaches the Earth in the form of electromagnetic (solar, or radiant) energy. The flux of this energy ranges over a broad spectrum of wavelengths, including visible light, and about a third of this huge flow is reflected by clouds and surfaces. Nearly all of the remainder is absorbed by oceans, land, and the atmosphere, converted to thermal energy, and reradiated by the planet. Geo-thermal energy results from the original gravitational accretion of the Earth's planetary mass and from the decay of radioactive matter. These flows drive the grand tectonic processes that continually reorder the oceans and continents and cause volcanic eruptions and earthquakes.

FIGURE 1.1 Matrix of energy conversions. Where more possibilities exist, only one or two leading transformations are identified.

Only a tiny part of radiant energy is transformed by photosynthesis into new stores of chemical energy in plants. These stores provide the irreplaceable foundation for all higher life. Animate metabolism reorganizes nutrients into growing tissues and maintains body functions and, in all mammals, also constant body temperature. Digestion also generates mechanical (kinetic) energy of working muscles. In their energy conversions animals deploy their muscles in search of food, reproduction, escape, and defense, but these functions are limited by the size of their bodies and by the availability of accessible nutrition.

Humans can extend these physical limits by using tools and harnessing the energies outside their own bodies. Unlocked by the human intellect, these extrasomatic energies have been used for a growing variety of tasks; they serve both as powerful prime movers and as fuels that release heat during combustion. Two conditions must be satisfied in order for humans to convert these energies to their own uses. First, the requisite energy flows (water, wind) or potentials (animals, biomass, fossil or nuclear fuels) must be present in exploitable quantities. Second, humans must take the actions or deploy the controls necessary to capture or release these flows and potentials in useful forms. The triggers of energy supplies depend on the flow of information and on an enormous variety of artifacts.

These devices have ranged from such simple tools as hammerstones and levers to complex fuel-burning engines and reactors that can release the energy of nuclear fission. The basic evolutionary and historical sequence of these advances is easy to outline in broad qualitative terms. Like any nonphotosynthesizing organism, humans require food. This is their most fundamental energy need. Foraging and scavenging by early hominids was very similar to the food acquisition strategies of their primate ancestors (Whiten and Widdowson 1992). Although some primates have a rudimentary tool-making capability, only hominids have explored this potential in a sustained manner.

Tools have given people many mechanical advantages in the provision of food, shelter, and clothing. The mastery of fire greatly extended humanity's range of habitation and set humans further apart from animals (Goudsblom 1992). Later, the invention of better tools allowed people to harness domesticated animals, build complex muscle-powered machines, and convert a tiny fraction of the huge kinetic energies of wind and water into useful mechanical power.

These new prime movers greatly enlarged useful power under human command, but for a very long time their effective use was circumscribed by the nature and magnitude of the captured flows. Most obviously, this was the case with sailing. Solar energy inputs govern the basic patterns of atmospheric and oceanic circulation. Prevailing wind flows and persistent ocean currents are fashioned by location and the interaction between land and water masses. These grand flows steered the late fifteenth-century European transatlantic voyages to the Caribbean and prevented the Spaniards from discovering Hawaii even after nearly three centuries of sailing through the Pacific.

The development of controlled combustion in fireplaces, stoves, and furnaces enabled people to turn the chemical energy of plants into thermal energy. Society began to use this heat not only directly in house...

Table des matières

• Cover
• Half Title
• Series Page
• Title
• Copyright
• Contents
• List of Illustrations
• Acknowledgments
• 1 Energy and Society
• 2 Energy in Prehistory
• 3 Traditional Agriculture
• 4 Preindustrial Prime Movers and Fuels
• 5 Fossil-Fueled Civilization
• 6 Energy in World History
• Basic Measures
• Chronology of Energy-Related Developments
• Power in History
• Suggested Readings
• References
• About the Book and Author
• Index