This is chapter 3 of the "The Macroscope" by Joël de Rosnay


The energy crisis has revealed the physical aspect of human society in sudden and dramatic fashion. Nothing can escape the implacable laws of thermodynamics; human society, like any machine or organism, is no exception. Economists are finding this out now, apparently with some surprise, in the wake of the discoveries of biologists and ecologists.

The necessary tools for considering the overall picture of the flow and degradation of energy in human society--the metabolism of the social organism, its primary function of self-maintenance--have been available for only a short time. Observing this metabolism through the macroscope, we see its dynamic behavior, heretofore impossible to grasp from within.

Out of the relationship between the "anatomy" and the "physiology" of society the long-unsuspected link between energy, economy, ecology, and entropy has been brought to light. This relationship not only reveals the possible causes of the ills of the social organism, it suggests the kinds of remedies that one might apply to a system on which the lives of all of us depend.

It has taken several years for biologists to arrive at an all-encompassing vision of the flow of energy in living systems and to create the new discipline that we now know as bioenergetics ( see notes ). Yet most biochemistry textbooks used by medical students have retained the analytical approach, describing in detail the behavior and functions of families of molecules, while the systemic approach considers the universal functioning of the cell. The situation is still worse when one tries to study the ecosphere as a whole. Until now the piecemeal analytical approach alone has prevailed. Going beyond bioenergetics, then, I want to propose the term ecoenergetics to show the need for a global approach devoted to the study of the regulation of energy flows in society.

Ecoenergetics must depend on both the systemic and the analytical approaches. With the former we want to proceed to a global study of the transformation and utilization of energy in society. With the latter we want to make a detailed analysis of all transfers of energy that affect the functions of production, consumption, and recovery in the social system. This study is an energy analysis.

The purpose of ecoenergetics is to find ways to keep the industrial and economic activities of man from interfering with nature's cycles-- above all, to establish bases for real and effective cooperation between man and nature, abandoning forever the old idea of domination. This chapter, then, will address itself to analysis of the crises we face and new proposals that look toward long-term solutions.


The story of society is usually told in history books as the political and economic evolution of a country. Yet the laws of energy are also significant. Why not retell the history of social organization from the point of view of energy? The approach is justified because energy laws have priority over political and economic laws. Energy laws are the basis of action; energy is essential to maintenance, to change, and to progress in any organization. Every surplus of energy represents "a leap forward." Prebiological evolution (that which preceded the appearance of the first cells) provides an excellent example.

In the primeval oceans the first organisms found themselves surrounded by energy-rich organic substances that had been accumulating for millions of years. The discovery was like that of man's finding fossil fuels deep in the earth. The energy released through fermentation gave these rudimentary organisms the means to survive, but only in a marginal way and while accumulating toxic wastes in their environment. Then respiration reactions coupled with photosynthesis made possible the complete and clean combustion of organic substances into carbon dioxide and water. Respiration released about four times more energy than did fermentation. Having much more energy available than they needed for survival, the living organisms benefited from an energy surplus. This is the capital that was invested in the immense enterprise of biological evolution.

In the evolution of societies the domestication of energy has taken place in three major stages, the third of which has scarcely begun. The first stage consisted of the long phase of human survival through the use of the earth's energy income. The second stage began about 150 years ago with the increased depletion of the energy capital of this planet. Finally, in our time there is the beginning of a progressive return to more efficient exploitation of the income of the ecosystem, associated with the planned use of its capital and the putting to work of nuclear energy .

The nomad hunter of prehistoric times was at the mercy of the great energy forces of the earth: fire, flood, storm, drought, and wild animals. Having barely enough energy for himself, he was unable to invest energy in the maintenance of even a rudimentary social organization. He could only collect the energy scattered throughout his environment and use it as he needed it, for he had no way of storing it.[1]

With the development of agriculture and metallurgy, mankind entered a phase of energy concentration. Grain and other foods were stored in baked earthenware pots. Pipes and canals channeled energy. Ovens concentrated heat, baked articles of clay, and smelted metals. People settled in fertile valleys and domesticated solar energy through the improvement of agricultural techniques. They gathered around large stores of food, establishing a defense system to protect themselves from the elements wild animals, and other tribes. The presence of food in reserve freed some men from seasonal constraints, thereby allowing time for the production of crafts and for invention.

The concentration of men and energy led inevitably to the control of men and the control of energy. The exploitation of biological energy brought rule and servitude--of one man by another man. Slaves, galley slaves, and serfs were inexpensive machines that were easy to control. Harnessing the physical energy of the elements led to the expansion of navigation by sail, the construction of canals, dikes, and dams, and the operation of wind and water mills. The improved efficiency of domestic animals, tools, and machines facilitated the processes of extracting and storing energy. Consumption increased and the rhythm of evolution quickened.

The transition to the second stage of the domestication of energy coincided with the discovery and use of the mineral resources coal and oil-- the earth's capital. The subsequent period of the explosive exploitation of resources has been but a few moments in geological time.

Social organization continued, becoming more complex in cities. Coal, steam, and machines were in the ascendance as work became specialized and factories were built; this was the time of railroads and transatlantic ships. Industrial expansion at the end of the nineteenth century and the beginning of the twentieth saw the birth of capitalism, the establishment of a working class, and the new subservience of man through the work contract.

Oil is inexpensive energy; it made possible electricity, the automobile, and jet aircraft; it fostered the amazing explosion of industrial power, individual consumption, transportation, and communication. But it also led to the depletion of a precious capital, the abuse of the environment, and economic and political imbalances.

In the face of the crisis, society's reaction is to call for the best available alternative source of energy: nuclear power. But this substitution is expensive in terms of capital, labor, and information--to say nothing of the new dangers it introduces- Caught between two great stages of human development. nuclear power may require even greater amounts of accumulated capital--money, goods, and technology--than the actual use of the earth's resources, even if fuel consumption were very low.

This short history of energy demonstrates that human societies have not escaped its implacable laws. The more complex a society, the more it will need significant quantities of energy to maintain itself. In every system in nature, organization continues until the energy cost of an increase in complexity is equal to the total energy budget available to the system. When this budget is exceeded, or when the sources of energy are exhausted, the systems become disorganized and disappear.

The same conditions apply to social systems. In a complex organization each individual is bound to the others by a complicated network of interdependent functions that involves exchanges of energy, materials, and work. Such an organization must divert to its own use a part of the energy budget that should have been distributed to each individual. In modern societies almost half of the energy received by individuals-- in the form of wages, income, manufactured goods, and food--must be returned to the "organization" (the government) in the form of taxes in order to ensure the survival of the social system.


The principal energy laws that govern every organization are derived from two famous laws of thermodynamics. The second law, known as Carnot's principle, is controlled by the concept of entropy.

Entropy and the Science of Heat

Today the word entropy is as much a part of the language of the physical sciences as it is of the human sciences. Unfortunately, physicists, engineers, and sociologists use indiscriminately a number of terms that they take to be synonymous with entropy, such as disorder, probability, noise, random mixture, heat; or they use terms they consider synonymous with antientropy, such as information, neguentropy, complexity, organization, order, improbability.

There are at least three ways of defining entropy: in terms of thermodynamics (the science of heat), where the names of Mayer, Joule, Carnot, and Clausius (1865) are important; in terms of statistical theory, which fosters the equivalence of entropy and disorder -- as a result of the work of Maxwell, Gibbs, and Boltzmann (1875), and in terms of information theory, which demonstrates the equivalence of neguentropy (the opposite of entropy) and information -- as a result of the work of Szilard, Gabor, Rothstein, and Brillouin (1940-1950).[2]

The two principal laws of thermodynamics apply only to closed systems, that is, entities with which there can be no exchange of energy, information, or material. The universe in its totality might be considered a closed system of this type; this would allow the two laws to be applied to it.

The first law of thermodynamics says that the total quantity of energy in the universe remains constant. This is the principle of the conservation of energy. The second law of thermodynamics states that the quality of this energy is degraded irreversibly. This is the principle of the degradation of energy.

The first principle establishes the equivalence of the different forms of energy (radiant, chemical, physical, electrical, and thermal), the possibility of transformation from one form to another, and the laws that govern these transformations. This first principle considers heat and energy as two magnitudes of the same physical nature (Fig. 68).

About 1850 the studies of Lord Kelvin, Carnot, and Clausius of the exchanges of energy in thermal machines revealed that there is a hierarchy among the various forms of energy and an imbalance in their transformations. This hierarchy and this imbalance are the basis of the formulation of the second principle.

In fact physical, chemical, and electrical energy can be completely changed into heat. But the reverse (heat into physical energy, for example) cannot be fully accomplished without outside help or without an inevitable loss of energy in the form of irretrievable heat. This does not mean that the energy is destroyed; it means that it becomes unavailable for producing work. The irreversible increase of this nondisposable energy in the universe is measured by the abstract dimension that Clausius in 1865 called entropy (from the Greek entrope, change).

The concept of entropy is particularly abstract and by the same token difficult to present. Yet some scientists consider it intuitively; they need only refer mentally to actual states such as disorder, waste, and the loss of time or information. But how can degraded energy, or its hierarchy, or the process of degradation be truly represented?

There seems to be a contradiction between the first and second principles. One says that heat and energy are two dimensions of the same nature; the other says they are not, since potential energy is degraded irreversibly to an inferior, less noble, lower-quality form--heat. Statistical theory provides the answer. Heat is energy; it is kinetic energy that results from the movement of molecules in a gas or the vibration of atoms in a solid. In the form of heat this energy is reduced to a state of maximum disorder in which each individual movement is neutralized by statistical laws.

Potential energy, then, is organized energy; heat is disorganized energy. And maximum disorder is entropy. The mass movement of molecules (in a gas, for example) will produce work (drive a piston). But where motion is ineffective on the spot and headed in all directions at the same time, energy will be present but ineffective. One might say that the sum of all the quantities of heat lost in the course of all the activities that have taken place in the universe measures the accumulation of entropy.

One can generalise further. Thanks to the mathematical relation between disorder and probability, it is possible to speak of evolution toward an increase in entropy by using one or the other of two statements: "left to itself, an isolated system tends toward a state of maximum disorder" or "left to itself, an isolated system tends toward a state of higher probability." These equivalent expressions can be summarized:

Potential energy -> entropy

Ordered energy -> disorganized energy (heat)

High-quality energy -> heat (low-grade energy)

Order -> disorder

Improbability -> probability

The concepts of entropy and irreversibility, derived from the second principle, have had a tremendous impact on our view of the universe. In breaking the vicious circle of repetitiveness in which the ancients were trapped, and in being confronted with biological evolution generating order and organization, the concept of entropy indirectly opens the way to a philosophy of progress and development. At the same time it introduces the complementarity between the "two great drifts of the universe" described in the works of Bergson and Teilhard de Chardin.

The image of the inexorable death of the universe, as suggested by the second principle, has profoundly influenced our philosophy, our ethics, our vision of the world, and even our art. The thought that by the very nature of entropy the ultimate and only possible future for man is annihilation has infiltrated our culture like a paralysis. This consideration led Leon Brillouin to ask, "How is it possible to understand life when the entire world is ordered by a law such as the second principle of thermodynamics, which points to death and annihilation?"

Energy and Power

There can be no production of work without a previous concentration of energy or the existence of some reservoir of potential energy (such as the sun, the gasoline in a car, a hydroelectric dam, a storage battery, a steam boiler). This energy must then flow from the reservoir to a sink in which it is degraded and dispersed in entropy. Carnot's laws show that this loss of quality of potential energy is necessary to the functioning of any engine. The higher the drop in potential, the greater is the quantity of work produced. In a thermal engine this drop happens between the boiler (the hot source) and the condenser (the cold sink).

The law of potentials says that the flows of heat, electricity, or liquids that leave the reservoirs are a function of the size of the stored quantities. For example, the intensity of the current in an electrical circuit depends on the difference of potential between the generator and the resistance of the circuit. The flow of income from invested capital is proportionate to the total value of the capital.

To produce work from energy it is necessary to transform the energy from potential to actual. The quantity of useful energy released per unit of time is measured in units of power. The concept of power is therefore very general. We speak of the power of an electric generator, of a locomotive, of the sun's rays; we speak of the power of a country, an army, an economy, a political group. To release power requires a paradoxically small amount of energy in the form of operating energy, or information. The capacity to release large quantities of energy through the amplifying nature of information is commonly called the "power" of an individual. Thus human power controls physical power through information.

The amplification of information modifies the balance of power. To be applicable, the capacity for making decisions requires a tilting of the balance of power. For this reason any assembly, board of directors, or jury must have a majority, if only of one person. For the same reason the takeover of an organization often requires the gaining control first of the means for releasing power.

In 1922 A. J. Lotka proposed the interesting "law of maximum energy," which he applied to biological evolution ( see notes ). The law said that one of the factors that seem to have the most importance in the survival of an organism is the production of a large quantity of energy. This energy is used in maintaining the structure, in reproduction, and in growth. The creation of maximum power thus appears to be a condition for survival in the struggle for life. This law is also valid for human organizations.

Power and growth must then be the two principal factors of selfselection of a system. But power is released only at the expense of a significant waste of energy. This waste results from the lowering of efficiency in metabolic processes. And this efficiency is maintained at a remarkably constant level, even for open systems of a very different nature.

In all open systems the transfer of energy takes place by means of coupling processes: the input of one system is the output of another. The observation of very many reactions shows that the coupling process always develops an "optimum yield" that corresponds to maximum power. This yield is in the neighborhood of 50 percent of ideal efficiency.

Consider an example. The dropping of a weight produces enough power to raise another weight, to which the first is linked by a rope and pulley. It is a coupled process: the potential energy of the higher weight, transformed into kinetic energy by its fall, causes the storage (in the medium of the other weight) of a supply of potential energy. This energy in turn can produce new work (Fig. 69).

Obviously two equal weights will lead to no movement, no work, no storage of energy. However, if this ideal system should be set in motion, the efficiency of the coupling process would reach 100 percent. In fact the fall of the first weight, with the help of the second, will store an exactly equal amount of energy.

Consider another extreme case. The right-hand weight is now equal to zero and the left-hand weight is released. There is a rapid fall and an impact on the ground. All the kinetic energy is lost in heat and thus no energy is stored.

These two extreme cases demonstrate that the only arrangement that will allow the simultaneous release and storage of energy in a minimum of time is that in which the weight on the right is equal to half the weight on the left. There is of course an energy loss in the form of heat at the moment of impact, but the maximum load is raised in the minimum amount of time. If the lighter weight were heavier, the process would be extremely slow. If it were lighter, too much energy would be lost in heat at the moment of impact and the yield would be still less ( see notes ).

The generalisation of this principle to an entire category of irreversible processes that take place in open systems was proposed during the 1950s by physicists of the school of "thermodynamics of irreversible processes" ( see notes ). Their work showed that each of the magnitudes such as voltage, temperature gradient, gravity, and concentration can be considered a thermodynamic force (or potential). Coupled to each force is a flow whose speed is proportional to the force that determines it. In the examples above, this flow would be an electric current, heat, the speed of a body in motion, or a flow of molecules. Once again one discovers the state and flow variables and their controls, encountered in the preceding chapters.

An interesting approach to the law of optimum yield can be made on the ground of information. The power of a computerized data bank for storage and retrieval of bibliographical references can be expressed as the maximum amount of useful information that can be obtained in

a minimum amount of time. When the user's request of the data bank is very precise, only a small number of useful references will be obtained. At the same time there is the danger of overlooking many references that may be related to the original request. When the request is more general (therefore less precise), the computer will produce a large number of references, some of which will be useful while others will be of no interest. In this event a lot of time must be spent sorting out the computer's responses. Experience has shown that optimum yield is obtained in the neighborhood of 50 percent "noise," or useless information. The user generally settles for a compromise in which he is certain of having rapidly found nearly all the references that he considers useful, even * though he has to pay for them with 50 percent noise.

Generally speaking, mathematical equations indicate that, in all coupled processes, maximum power is best obtained when the ratio of forces is equivalent to 1:2. This means that man (as well as plants or animals) prefers to sacrifice yield to power. This is readily seen in the consumption of energy in society. This very simple and very general law, which applies equally to physical, biological, and social systems, is expressed by Figure 70.[3]

Another law that applies to a large number of systems is the law of diminishing returns that is so well known to economists. When a global result is obtained by the multiplication of several factors, the growth of only one of them need be limited to cause the global result to stretch also toward an unreachable or asymptotic limit. The mathematical function that illustrates this law is a hyperbole. In spite of the very important increase in the quantities represented on the horizontal axis, the yield represented on the vertical axis no longer increases (Fig. 71).

One encounters such law in biology, in the saturation of active sites of enzymes; in agriculture, where in spite of the massive injection of fossil fuels the energy yield of agricultural processes (in terms of calories consumed by man) reaches a limit; in accounting, where the efforts used to obtain two figures after the decimal point are far superior to the actual utility of such precision in the accounts; and in navigation, where after a certain speed has been reached no effort of the crew or addition of sail will have more than a marginal effect on increasing the speed.

The lesson of the law of diminishing returns is severe: the limit of return has long since been attained--whether or not the fact has been realized--in numerous organizations, business firms, and work teams. Nevertheless, continuing to try to improve returns, man expends prodigious amounts of ingenuity, large quantities of energy, and important human and material resources--while the limiting factor remains completely unnoticed.


Like every living organism, human society transforms, stores, distributes, and wastes energy in order to survive, produce work, and evolve. The circulation of energy in its structures and the transformations that take place there are its metabolism.

Metabolism includes all "biological machinery," human and animal, and all mechanical and electronic equipment that men use in their social activities. The biological machinery depends on food, the mechanical machinery on oil and electricity--more generally, on fossil fuels. The biological machinery and the world population of mechanical and electronic machines all transform energy into useful work, thereby allowing the maintenance and development of the social organization (Fig. 72).

The metabolism of a man walking at a normal pace consumes 200 watts ( see notes ). His minimum energy requirement is about 1,320 kilocalories per day, or 2,500 kilocalories per day for moderate activity.[4] With the help of fire, prehistoric man used 4,000 kilocalories, or twice the amount of energy needed for his metabolism. In a primitive agricultural society man consumed about 12,000 kilocalories; with the beginning of the industrial era, he used about 70,000 kilocalories. Today the average American uses 230,000 kilocalories per day. A well-known statistic, one that it is helpful to recall, is that America, with only 6 percent of the world's population, consumes 30 percent of the world's energy, or 20 x 1015 kilocalories.

The biological machinery of a country like France is made up of 50 million individuals (not counting the animal population). It produces 4.3 x 1010 hours of effective work annually, or the equivalent of about five million years of work.[5] It consumes in food energy alone 45 x 1012 kilocalories of food per year. It produces 35,000 tons of waste per day and 12 million tons of garbage per year. If you also count industrial and commercial wastes, 25 million tons of waste are produced each year. Annual energy consumption per capita reached 32 million kilocalories in 1973, or a total annual consumption of 1.6 x 1015 kilocalories for all France.

Other than food calories, all energy spent by society is consumed by the machinery used by men. World consumption of energy was 58 x 1015 kilocalories in 1974, and it will probably reach, with a rate of growth of about 4 percent per year, 100 x 1015 kilocalories just before the year 2000.

Thermal energy, released mainly through the combustion of oil and its derivatives, turns the motors of machinery, automobiles, and electric generators. All these machines can be grouped in four large categories: transportation, industry, commerce, and domestic use.

The aggregate flow of the circulation of energy in the social organism follows the law of optimum yield found in all open systems. The total energy yield of social systems seems to stabilize at about 50 percent or an amount corresponding to the production of maximum power required by the intensity of their metabolism. In all large, developed countries, the overall return seems to be 50 percent. Figure 73 below shows the use of energy in American society.

All forms of metabolism produce wastes and entropy. But with the acceleration in the consumption of energy and the consequent acceleration in the intensity of metabolism of the social system, the action of man on nature assumes alarming proportions. Three major energy crises have arisen in our industrial civilization as a result of man's activity: the energy (and raw materials) crisis, the food crisis, and the environmental crisis.

A truly systemic approach to the energy problems must be worldwide in scope and must hold for the long term. Thus I prefer to consider in broad terms the possible long-term effects of man's energy-related activities on the climate of our planet rather than describe the effects of specific pollutants.[6]

The total quantity of gaseous, solid, and liquid wastes produced by the social organization's metabolism now reaches proportions that are about equal to the total quantity of elements recycled by the ecosystem. We are long past the time when the aggregate of wastes produced by humanity seemed, in comparison with natural processes, only a drop in the ocean. Now we know how to measure the amounts of water, oxygen, carbon, nitrogen, and sulphur that are present in the great reservoirs of the ecosystem, and we can compare these quantities with the production that results from man's activity. The results show that man is in direct competition with nature.

Everything in nature that breathes produces altogether 720 billion tons of carbon dioxide per year. In addition, the total amount of sulphur that circulates annually in the atmosphere and in the biogeochemical cycles amounts to 500 million tons. How do these figures compare to man's contribution? Like one huge breathing organism, human society in 1977 was exhaling 22 billion tons of carbon dioxide annually, mainly from the combustion of fossil fuels. By 1980 the amount of carbon dioxide being produced will reach 26 billion tons. The contribution of industrial societies will then amount to nearly 4 percent of that of nature. As for the production of sulphur dioxide, it rose in 1975 to 760 million tons, mainly as a result of the combustion of oil in thermal power plants. In the year 2000 man's contribution will equal that of nature.

Once again the interdependence of the factors eludes us. Excess heat, dust, and carbon dioxide are directly linked to industrial activity and thus to the acceleration of economic growth. Will they lead in the long range to a rise or a fall in the temperatures of our planet? The question is often discussed; what effect would it have? the cooling that results from atmospheric dusts or the "greenhouse effect" of carbon dioxide? These questions are difficult to answer; the earth also readjusts its equilibrium, though not always to our satisfaction.

All of the world's energy ends in the form of heat. First it is stored in the biosphere and in water, then it is dissipated in the atmosphere and radiated into space. The total amount of heat released by human society can easily be measured because it is a function of the consumption of energy, and that is a well-known figure. Climatologists estimate that there could be significant changes in the world's climate if the heat released by man were to reach one percent of the amount of energy that comes to us from the sun. Yet the heat produced by the fourteen northeastern states, which consume 40 percent of all energy in the United States, amounts to 1.2 percent of the total energy received from the sun over the same area. The figure will rise to 5 percent by 2000 a figure already reached in Manhattan alone.

Local climatic modifications have already been observed. They can be seen in the cloud formations downwind from large power plants. A power station producing 20,000 megawatts can cause storms and heavy rains, as was demonstrated by studies in St. Louis in 1973. The modification of the microclimate of large cities is also visible (see p. 32). It would appear that city dwellers are condemned to perpetually gray and humid weather in winter and unpleasant weather in summer, all because of thunderstorms. And the climate of the entire world may suffer the same fate, for the problems created by the evacuation of heat in the atmosphere are becoming serious. The use of energy grows at an exponential rate: nearly 4 percent per year in the United States and 6 percent per year in the rest of the world. At this rate the limit of one percent of the sun's energy will be reached over the whole world in 130 years.

To the effects of excess heat we must add the greenhouse effect of carbon dioxide. Shortwave radiation coming from the sun easily penetrates the layer of carbon dioxide that surrounds the earth. But infrared rays reflected by the earth's surface cannot penetrate this layer, being trapped, they contribute to the warming of the atmosphere. The amount of carbon dioxide in the atmosphere, as a result of man's activities, increases by 0.2 percent per year. Presumably the greenhouse effect could raise the average temperature of the earth. But this is the reverse of the general cooling we have seen since 1940.

Perhaps the key to this paradoxical situation is to be found in the factors that increase the reflection of solar radiation by the earth. This reflection is called albedo. The regulatory role of albedo is a determining factor in the thermal equilibrium of our planet; because of it the earth maintains its temperature in a stationary state. The difference in temperature between the equator and the poles remains almost constant.

We learned several years ago, by means of photographs taken by meteorological satellites, that the surface area of the ice in the northern hemisphere exceeded by 12 percent the areas measured in the preceding years. Ice formed earlier and melted later. The differences were very marked beginning in 1972 and 1973, a period when, according to the Bulletin of the World Meteorological Organisation, an abnormal climate was observed ( see notes ).

According to Reid Bryson, director of the Institute of Environmental Studies at the University of Wisconsin, the cooling of the earth may be due to the increase in the quantity of dust particles and aerosols in suspension in the atmosphere. These dusts are dispersed in the atmosphere by natural causes (volcanos, desert winds, salt) and by human activity. Today their quantity totals 296 million tons (four million comes from volcanos). Of this total, about 15 million tons remains permanently in the upper atmosphere. Another two million tons could reduce the earth's temperature by 0.4deg. Centigrade. This is why the effect of dusts on the transparency of the atmosphere appears to be more important than the greenhouse effect of carbon dioxide.

One final factor comes into the picture. The increase in albedo has a more marked effect on the cooling at the poles than on the temperature of the tropics (because the sun's radiation travels laterally and penetrates a thicker layer of dust at the poles). The result is a much greater difference in temperature between the poles and the equator. The thermal machinery of the earth tries to equalize the difference, and this may well cause confusion and disturbance in the pattern of the prevailing winds.

In spite of rather troubling climatic conditions, one need not dramatize or despair. It is not yet certain that these disorders are the result only of the factors mentioned. Perhaps the world's temperature is passing through cyclical phases of which we are unaware. Then, although limited, the ecosystem is not static but is in dynamic equilibrium; its multiple stationary states can readjust themselves according to modifications resulting from human activities. Carbon dioxide, for example, whose concentration in the atmosphere continues to increase, is probably transformed little by little into carbonates and organic matter; that is, it is stored in the earth's sediments or in the wood of the forests.


The illusion of continuous economic growth is nourished by the false notion that the economy is an isolated cyclical process that escapes the energy laws of the physical world and the increase of entropy. The opposition between the circular monetary flows and energy flows, which move in opposite directions, and the potential for creating money have probably helped to enrich and reinforce this illusion. Perhaps we should look further, to the collective subconscious, to the roots of that mad dream of humanity that tries to balance and even reverse through economic growth the natural aging process of social organizations. It is a pathetic struggle against death.

In the end one must pay. The bill for growth has just been given us, and it is enormous. Our natural resources are being exhausted, the environment is endangered; inequalities, far from being removed, are greater than ever.

In fact there is nothing cyclical in the economic process. As in all open systems, the circular movement in reality is an irreversible, one-directional process--that of the degradation of energy and the increase of entropy. It is not surprising that in the "classical" economy the relationship between economics and ecology--better still, between energy, ecology, economics, and entropy--has long gone unnoticed. And this is the question at hand, not that of the economy of the environment. Economics and ecology are like a series of interconnected reservoirs, to draw from one more quickly than it can be refilled means emptying it eventually.

The classical economy is defined in terms of the distribution of scarce commodities. The ultimate resource, whose scarcity conditions that of all the others, is free energy.7 The economy of biological and ecological systems is built entirely on the recognition of the importance of this ultimate good. This economy is based on the management of an energy capital and the judicious use of information in order to "organize" the energy into products that can be assimilated directly by the cell, the organism, or the different species of the ecosystem.

Should not the traditional economic act be enlarged and enriched along the lines of this fertile relationship between energy and information? In the new ecoenergetics viewpoint, the economy should deal with the management and equal distribution of an energy reserve and an energy flow, coupled with the "information" (transformation) of this energy into goods and services useful to society.

Universal Currency: The Kilocalorie

A systemic approach to the processes that link the economy and ecology must try to go beyond the already outdated concept of monetary value and complete it with the concept of energy cost, expressed in a universal unit of energy. This unit might be the kilocalorie; it would allow, at the level of the control and use of energy, a unification of biological, ecological, and socioeconomic systems.

The table below gives several estimates of magnitudes in terms of kilocalories ( see notes ).

Energy from the sun 3.7 x 1018 Kcal/day
Total world consumption, 1974 58 x 1015 Kcal
Food consumption in France 45 x 1012 Kcal
Energy needed to produce:
aluminium (one ton) 50 x 106 Kcal
paper (one ton) 10 x 106 Kcal
steel (one ton) 7.5 x 106 Kcal
cement (one ton) 2.2 x 106 Kcal
petroleum (one ton) 1.3 x 106 Kcal
Energy needed to produce a car (1.5 tons) 32 x 106 Kcal
Energy needed to feed a man for 30 years (subsistence only) 32 x 106 Kcal
Energy needs of a man 2,500 Kcal/day
Energy from one liter of gasoline 10,000 Kcal/day
Energy cost for one passenger on a transatlantic flight 6 x 106 Kcal

One of the keys to ecoenergetics is the determination of the economic value of the kilocalorie. Is it possible to arrive at a conversion factor that links monetary value and energy cost? Even a rough estimate would be very useful. One might begin with graphs showing the relationship between gross national product and energy consumption per capita and draw from them an estimate of the dollar value of the kilocalorie according to the various economies.

In 1971 Howard Odum proposed an energy equivalent of 10,000 kilocalories (the energy of one liter of gasoline) per dollar ( see notes ). Today the equivalent would probably be no more than 5,000 to 7,000 kilocalories per dollar. Nevertheless such an approximation makes it possible to compare energy flow and money flow more efficiently. It also makes it possible to determine the cost of noneconomic goods such as living trees, water, and oxygen. The comparison of dollars and kilocalories also clarifies the concept of energy-intensiveness, the energy demand of certain industrial processes. This demand is stated in terms of the relationship between kilocalories consumed and value added.[8] An energy-intensive industry spends up to 50,000 kilocalories per dollar in value added.

The transition from economics to ecoenergetics is justified in many other ways. In ecology one finds the economic equivalent of the fee

paid for finished work. This "payment" is based on an energy "price," and the "money" circulates in the form of materials useful to the community.

When a function is necessary to the maintenance of the structures of an ecosystem, the "reward" circuits, based on the mutual benefit of the species and the communities, are reinforced by feedback loops. Animals return to plants mineral substances (phosphates, nitrates, potassium) that are useful to plant growth. The "work" of animals (hunting, destroying, control of certain species, transfer of information) is the equivalent of a "service" paid for in food.

Regulation by kilocalories exists everywhere in the world of the producers and consumers of the ecosystem. Producers are stimulated when the flow of mineral substances that is returned to them is greater than the flow of food that they manufacture. Consumers are stimulated when the flow of food that they receive is greater than the flow of mineral substances that they return to the plants. But every balanced interdependence must depend on self-stimulating loops; in other words, the agents that participate in these loops must be rewarded. The stimulation of the transforming agents can be thought of as an "individual" motivation. Without reward or stimulation, an energy circuit dries up and disappears. Through the play of reinforcement loops and their interconnections, the ecosystem selects those species and individuals who contribute most effectively to the functioning and maintenance of the whole.

Finally, the ecoenergetics approach brings out the link between time and energy. The empirical law is simple: a gain in time must be paid for in energy. If we want to travel fast, we use a car or a jet; if we want to produce fast, we use assembly lines and automation. For the minutes saved we must compute the kilocalories spent. To save time, one increases the amount of energy subsidy fed into the social megamachine. This vicious circle of economic growth still believes that it liberates time. It saves time, but at what expense? in the face of what deadline?

Energy Analysis

The basic tool of ecoenergetics is energy analysis ( see notes ). This method will probably turn out to be one of the most fruitful in determining which solutions to apply to the crises we meet.

In order to find and put to work new sources of energy or to choose the most advantageous ways of saving energy, we must first be prepared to set up complete and detailed energy balance sheets. Today we can do this, thanks to new techniques of energy accountability that have come chiefly from chemical engineering, biology, and ecology. Together these techniques make up energy analysis.

The forerunners of energy analysis were Raymond L. Lindeman

of Yale, who in 1940 drew attention to the quantitative relationships that exist in nature between the various consumers of an ecosystem and Howard Odum of the University of Florida. In 1957 Odum published a famous article, now a fundamental document of ecologists, in which he made a complete analysis of the energy flow (in kilocalories per square meter per day) that circulated within an ecosystem composed of the flora and fauna of a little river.

Other ecologists have applied these methods to the energy accounting of small communities dependent on hunting and fishing (Eskimo and African villages), and they have been able to connect energy factors to economic elements. But the true birth of energy analysis--and with it the beginnings of ecoenergetics--coincides with the reinterpretation of the results of economic analysis in terms of energy units.

The father of economic analysis is Vasilli Leontieff of Harvard, winner of the Nobel Prize in economics in 1972. As early as 1946 Leontieff had made an input-output matrix based on thirty sectors of the American economy. Input-output matrices are tables made up of a large number of entries which correspond to the different sectors of the economy. They follow and measure, from producers to consumers, the variations in supply and demand for raw materials, semifinished and finished products, and services. The results of economic analysis, expressed in monetary units, make it possible to develop the concept of value added.

Energy analysis is an offshoot of economic analysis but draws its inspiration from methods used in chemical engineering. It tries to estimate the energy cost of every industrial transformation that uses energy, raw materials, or work. Working backward, one retraces one by one the stages in the manufacture of a given product, constructing a tree whose branches become increasingly ramified. The amount of energy used at each step is measured, and in the end all the kilocalories expended are added up. The first applications of energy analysis were made in the automobile industry in 1972 and in food production in 1973.

The calculation of the energy costs in the manufacture of a car in the United States was made by Stephen Berry and his team from the chemistry department of the University of Chicago in 1972 ( see notes ). To build an automobile weighing 1.5 tons requires an expenditure of 32 million kilocalories. Yet thermodynamic calculations show that in theory the necessary quantity is only 6 million kilocalories. The 26 million kilocalories of excess energy (80 percent of total consumption) is used only to save time. Thus the automobile industry consumes more free energy than it needs--in order to increase efficiency in production, to lower prices, to sell more cars, and thus to realize greater profits.[9]

The difference between economic analysis and energy analysis is a difference on the time scale. If economists were to determine the depletion of resources by extrapolating from longer and longer terms, their estimates would catch up with those of the thermodynamicists.

Economic estimates are based on the measure of energy needed for an infinitely slow and reversible process. Yet the economic system is an open system crossed by an irreversible flow of energy. Moreover, as the law of optimum yield indicates, we prefer to sacrifice yield to power-- which causes us to waste, on the average, about 50 percent of the available energy in order to achieve more rapid change. Supplementary energy, which makes possible the transfer from thermodynamics to economics and which measures at the same time the "value" we assign to material things, is the energy subsidy. This subsidy says in energy terms that the cost is directly connected to the intensity or speed of the transformation. The aggregate energy subsidy is related to the speed of the metabolism of the social organism and therefore to the rhythm of its growth. It is well known that countries with the highest growth rate and the highest GNP are the largest consumers of energy.

The increase in free energy at each stage in the transformation of a product during its manufacture is the physical equivalent of the economic concept of value added. Energy reaches a maximum at the moment of purchase by the consumer, then declines more or less rapidly. But the consumer does not "consume" the product; he throws it back into the environment as soon as he decides it is useless. Thus some disposals retain a high level of free energy. The real waste is in the nonutilization of the free energy that remains in the discarded products.

Energy Analysis and Food Production

One of the most revealing applications of energy analysis has been in the entire area of food production. The production and distribution of food are among the most important functions of the social organism. This importance is indicated at the economic level by that part of the family budget allotted to food. In France it fell from 49 percent in 1950 to 27 percent in 1973; in the United States it accounts for less than 22 percent of the household budget. A money flow that represents about one-fourth of the total budget of the consumer sector must be balanced by an energy flow of at least equal amount.

Energy analysis shows that the total amount of energy spent on food production represents about 15 percent of the total energy budget of the United States and 22 percent of the total electricity budget ( see notes ). This

energy is used in farm operations, processing industries, transportation markets and stores, and at home in refrigerators, freezers, kitchen stoves and ovens. In 1973 Americans used six times more energy to feed themselves than was necessary for human metabolism. The rate of increase in the amount of energy needed for food production is higher than the population growth rate in the United States. All this serves to promote energy analysis and to pose long-term questions about the harmony of the formidable machinery of food production that supports the populations of the developed countries.

If one considers the different ecological chains and cycles from the transformation of solar energy in green plants to the lump of sugar in our coffee, the fat in a piece of meat, or the bread for breakfast, one sees that the growth and maintenance of agricultural yields required by demographic pressure and the rise in the standard of living have been made possible, just in the last fifty years, only by massive injections of fossil fuels into the agricultural processes. Considering all these processes together as one machine, it comes down to using more natural "solar" calories and ever more "fossil" calories as input in the hope of recovering in the output calories that can be consumed by the living organism.

Quite simply, the question is this: are we not spending, in our industrialized societies, more calories in input than we recuperate in output? In other words, is the input of fossil fuels greater than the output of calories in agricultural production? Above all, doesn't the ratio of calorie output to calorie input tend to diminish in disturbing proportions? If the answer to these questions is affirmative, then we can expect--as our industrialized countries are already aware--a shortage of calories perhaps less dramatic than that in the underdeveloped countries but leading nevertheless to uncontrollable increases in the cost of food products.

Applied to agriculture ( see notes ), energy analysis shows how energy from fossil fuels substitutes for the energy otherwise provided by the work of men domestic animals, and the natural elements. Fossil energy also substitutes for natural fertilizers, but the manufacture of nitrates, phosphates, and potassium fertilizers requires a higher expenditure of energy. Pumps used to irrigate crops, formerly operated by animal or wind energy, have been replaced by electric pumps and diesel engines. Instead of sunlight, fuel and electricity are used to dry fodder; they are also used to light and air-condition special barns devoted to the intensive raising of livestock.

The most significant results of energy analysis come from measuring the total energy input necessary to produce a given food product. David

Pimentel and his group from the College of Agriculture and Biological Sciences of the State of New York sought to determine, over a period of twenty-five years (1945-1970), the increase in the energy subsidy needed to grow one acre (0.4 hectare) of corn in the United States. They included in their energy analysis the labor of agricultural workers (kilocalories consumed per day); the energy cost of the manufacture of farm machines; the gasoline consumed; the energy cost of the production of fertilizers, insecticides, herbicides, and seeds; and the electricity or fuel used in the irrigation, drying, and transportation of the corn.

Their analysis revealed that in 1970 it required 2.9 million kilocalories per acre (the energy equivalent of 750 liters of gasoline per hectare) to produce the 8.16 million kilocalories contained in the harvested corn. Thus the energy yield was the equivalent of 2.82 calories per calorie invested. But in 1945 it had been 3.2 calories per calorie invested. Between 1945 and 1970, then, the energy yield from growing corn decreased by 24 percent, while the actual yield, in tons of corn per hectare, increased regularly.

Energy analysis was extended further by John S. Steinhart of the University of Wisconsin, who applied it to the entire agricultural and foodproducing system of the United States between 1940 and 1970. The results showed an increase in the gap between the energy needed for food production and the energy equivalent of the food needs of the American people during those years. The gap widens because the energy consumption connecting agriculture and the increase in the standard of living involves a growing use of canned, frozen, and prepared foods whose preparation or storage requires significant quantities of energy. This increase also reflects a higher consumption of food outside the home-- chiefly at places of work--and the fact that beef has a low rate of efficiency in transforming "solar" calories into "food" calories.

One of the most disturbing results is that we are approaching little by little the theoretical limits of the agricultural yield--an excellent illustration of the law of diminishing returns. The slope of the curve that traces the amount of energy needed to produce one food calorie, in the course of the history of United States agriculture, at no point becomes less steep, which confirms the fall in efficiency in the entire production process.

Such an evolution should be compared to that of the underdeveloped countries, or "primitive" cultures, where an investment of one calorie brings from five to fifty food calories in return. In our developed countries it takes from five to ten calories in fossil fuels to produce one food calorie.

The Competition Between Energy and Work

Energy analysis has also been applied to the problems of pollution caused by solid wastes, in attempts to determine the more advantageous of two solutions: to collect old papers and cartons for recycling or to burn them and use the energy for heating buildings.

There are interesting perspectives in the study of the consequences of substituting energy for human labor, the creation and elimination of employment, and the changeover from an energy-intensive manufacturing process to one that is labor-intensive.

There is a very close relationship between energy, labor, and production capital. Economists have long known that energy and labor vary in inverse direction ( see notes ). They compete for the same share of production capital. Because energy has the capacity to provide work, energy and labor are substitutes for each other.

Some examples will illustrate these relationships and their significance for energy analysis. The five industries that are the largest consumers of energy are aluminium, paper, steel, concrete, and petrochemicals. Together they consume 40 percent of all energy used in the industrial sector in the United States, yet they employ only 25 percent of the total labor force. Production capital is very important in these industries; heavy equipment, complex machinery, and automation all require high capital investment. But wherever energy is substituted for human labor, a more significant amount of dividends flows toward the stockholders. When energy prices are low, the cost of production capital is high, when prices increase, production capital shrinks.

There is a consequence of the competition between energy and labor. If energy prices continue to rise, the long-term tendency will show-- paradoxically--increases in employment and in wages. All things being equal, the share of national income that goes to reward labor will increase at the expense of capital income. From 1947 to 1971 the low cost of energy made it possible to replace manual labor with energy whenever it was feasible. The consequence, inevitably, was an impoverishment of the quality of work in the expansion of assembly lines and bureaucracy.

We can also use the economic input-output matrices, retranslating them into energy values in order to measure the total quantities of energy and labor (as goods and services) needed to reach a given level of production. Bruce Hannon of the University of Illinois did this in 1974.

To produce an additional $100,000 of aluminium, for example, 9.5 x 109 kilocalories and five persons would be needed. To produce the same supplementary value in tobacco (an industry that uses little energy) would require only 1.2 x 109 kilocalories and the creation of thirty-two new jobs. Thus a transfer of $100,000 in consumer demand from aluminium

to tobacco would reduce the consumption of energy by 33 percent and create twenty-seven new jobs.

Highway construction is one of the major consumers of energy because of its use of petroleum-based asphalt and concrete, whose production requires large quantities of energy. A $5 billion highway construction program consumes 55.4 X 1012 kilocalories and provides jobs, directly or indirectly, for 256,000 people. The same amount invested in a railway system would consume 20.1 x 1012 kilocalories and provide employment for 264,000 individuals--a gain of 8,000 employees over the highway construction program. And the same amount spent on a vast program of public health would certainly use energy, but it would make possible the creation of 423,000 jobs (167,000 more than the highway program, 159,000 more than the railway program).

Energy analysis will help in a positive way to make it easier to choose the most appropriate and advantageous means for resolving some of the problems created by the energy crisis, the food crisis, and the environmental crisis. Energy analysis will enable us to answer--with the figures to support our answers--questions of this type: Is it more costly to implement new sources of energy or to improve efficiency in the production of aluminium?


There are three principal ways to reduce our consumption of fossil fuels and raw materials: the implementation of new energy sources, the recycling of materials, and energy conservation. In the long term these will involve a transition to products whose manufacture consumes less energy, a greater emphasis in the economy on the services sector, and the implementation of "soft" technologies. These ways are well known; they are mentioned again only to emphasize the extent of the transformations through which society is passing.

The new energy sources, of which there is so much talk, are chiefly nuclear energy (fission and fusion), solar energy, and geothermal energy. Energy from the combustion of organic products, wind energy, or waterfalls can be considered derivative forms of solar energy.

The transformation of solar energy into heat is made possible by heating and air-conditioning systems. It can be transformed directly into electricity by photoelectric cells. Indirectly this energy can be released by the burning of organic waste, by the production of liquid fuels through chemical decomposition and of gases (methane) through bioconversions of manures by bacterial fermentation.

The recycling of wastes must be incorporated in a much more general process of the recovery of discarded materials--the equivalent in society

of the recycling achieved in the ecosystem by the decomposers ( see page 8 ). Recovery includes the reuse of objects and the recycling of materials in production. Discarded materials can be grouped in two categories wastes and debris (materials that have no use in a given economic context). In the long term the only valid means for rebuilding the great natural recycling loop is to involve the population in sorting out materials when they are discarded. For a small expenditure of energy and with careful use of information, each individual can reduce the entropy in a heap of discarded items. Machines can do this only at prohibitive cost.

Energy conservation is accomplished mainly through the retrieval of heat, through thermal isolation, and through the replacement of energy intensive industrial processes and energy-intensive transportation systems by more economical means. At least 25 percent of the world's energy could be saved by observing a few basic rules of energy conservation.

No matter how ingenious the solutions or how effective the discipline of the population when confronted with problems of waste, the real long-term solutions will come only with a radical remodeling of our way of living in society--living differently and living in cooperation with nature. This new perspective involves the bioindustry and ecoengineering.

The coming revolution in agriculture and in the food and chemical industries will be of a biotechnological nature. It will give birth to a bioindustry that will bring new solutions, based on soft technologies to the energy crisis and the degradation of the environment.

After the advent of agriculture about ten thousand years ago, the first agricultural revolution took place in the seventeenth century. It was marked by the techniques of crop rotation and the selection and hybridization of seeds. The second revolution came in the middle of the twentieth century with the mechanization of agriculture. The third revolution, now in preparation, will be based on biological engineering new methods of energy conservation, and the controlled use of natural cycles.

Better insight into the development of micro-organisms has already made it possible to produce proteins by growing yeast on hydrocarbons such as methanol and methane. The use of insect hormones to sterilize male insects assures the control of populations of insect pests--and this for a fraction of the energy cost required to produce pesticides.

But we must go further. Biological information collected over the last thirty years makes greater development possible. The agricultural and industrial revolution of the end of the twentieth century will depend on techniques that have hardly left the research stage: genetic engineering, enzyme engineering, bacterial engineering. There will be synthetic molecules performing the activity of natural enzymes, fermentation reactions controlled by computers, control and use of the basic reactions of photosynthesis, and (why not?) abiotic syntheses like those of the primeval

earth, when the first molecules of life appeared.

This revolution will see the appearance of a new form of slavery: the domestication of microbes, those docile and indefatigable workers. In order to replace man or some of his machines in numerous tasks, we can consider two directions, each corresponding to a form of slavery: the sophisticated electronic system of industrial robots (tremendous energy consumers) or biology and the slavery of the myriads of microbes that populate the biosphere. These two routes are already being traveled today, and it appears that the bioindustry and the domestication of microbes will be recognized as even more spectacular developments than the use of industrial robots with their great appetite for energy.

This revolution will free agriculture and the food industry from the vicious circle in which they are now confined by the exhaustion of energy resources, the decrease in the calorie yield of the agricultural machine, and the concomitant increase in the price of calories consumed by men.

Four sectors will probably dominate the bioindustry in the years to come: the production of chemical products by microbes; the domestication of enzymes; the electronic control of fermentation reactions and bioconversions in general (capable, for instance, of generating energy); and the control of the basic reactions of photosynthesis.

New Jobs for Microbes

There are not only pathogenic microbes, there are useful ones as well. We have long been putting them to work to ferment wine and beer, to make bread dough rise, and to produce yogurt and cheese. Under the general title of decomposers, these microorganisms are the recycling agents of the ecosystem.

Today microorganisms are finding new employment in industry. They are used as miniature factories in the manufacture of dozens of commercial products such as amino acids, enzymes, solvants, insecticides, and antibiotics. The energy crisis and the food crisis are accelerating this mobilization of useful microbes.

Biological processes in nature are controlled by catalysts of amazing efficiency--the enzymes. Because of them the reactions of life occur at room temperature and in mild conditions, in complete opposition to the energy-intensive processes of the chemical and food industries. Moreover, the by-products of the metabolism of microbes are either useful substances or harmless molecules like carbon dioxide and water.

The secret of microbe domestication lies in the control of certain processes which occur at the molecular level. During the last thirty years there has been considerable progress in research in molecular biology; half of the Nobel Prizes in medicine awarded in the last fifteen years were for advances in that field.

The complexity of the technology and information required by those who work with microorganisms and enzymes might be compared to the complexity of knowledge that contributed so much to the authority of the atomic scientists in the 1940s and 1950s, which led to the control of nuclear energy--and to the manufacture of atomic weapons. It is this mass of accumulated knowledge in fields related to biology and chemistry--microbiology, molecular biology, genetics, biochemistry, organic chemistry, and chemical engineering--that allows us to predict an imminent revolution.

The ideal microbe is one that can produce an excess of a substance that has medical or industrial interest. Modern techniques issue from molecular biology, particularly from the work on cellular control that earned Nobel Prizes in medicine in 1965 for Lwoff, Monod, and Jacob who discovered ways to stop or start at will the cellular machinery. The techniques of genetic engineering in this respect are also very promising. By transferring certain sequences of genes into bacteria that are easy to cultivate but are incapable of producing a given antibiotic or a given useful substance, one can change them into efficient producers of a given substance. Insulin, for example, can be made by the common bacteria of the intestine, E. coli. New antibiotics that enable us to combat more effectively bacteria that have become resistant to known antibiotics could also be made "to measure."[10]

Techniques of genetic engineering will also enable the production of biofertilizers by transferring genes that allow nitrogen fixation in symbiotic bacteria living in the roots of plants ( see notes ). Millions of people die of starvation because our industries do not know how to transform nitrogen (the 80 percent of the air we breathe that passes through our lungs unchanged) directly into ammonia or into nitrogen-containing molecules (the principal building blocks of proteins). In nature the nitrogen present in the air is transformed into ammonia by the symbiotic bacteria that live with vegetables such as peas and beans. The biological catalyst that effects the conversion of nitrogen to ammonia is an enzyme called nitrogenase. Its efficiency permits the annual conversion of 50 million tons of nitrogen (350 kilograms per hectare of vegetable crops, or about 770 pounds per half acre). In comparison, the fertilizer industry treats the same amount of nitrogen annually--50 million tons in 1973--but only by creating temperatures of 400deg. centigrade and pressures of 200 atmospheres. It takes 20 million kilocalories to synthesize a ton of ammonia. Thus the

use of microorganisms in this type of process will not only have the advantage of supplying the human population with a nutritional supplement, it will also reduce the very high energy bill of the nitrogen fertilizer industry.

Microbes also know how to make proteins readily usable in human and animal nutrition. The decrease in the total quantity of proteins in the world--the result of poor harvests due to drought, insufficient catches of fish (particularly the anchovies used in fish meal), and the rise in the price of soybeans--is good reason for the growing bioindustry to produce proteins from microorganisms.

And the production-of proteins by microbes offers other advantages: production is independent of agricultural and climatic conditions, the microbe biomass grows very quickly (this is particularly desirable in obtaining high yields), and production is not limited to the areas available for plant cultivation.[11]

Certain large corporations, such as British Petroleum (BP), used petroleum to grow yeast; others, such as ICI, use methanol. But one of the most interesting procedures is the one developed by the Bechtel Corporation and the University of Louisiana, in which microbes are fed abundant and inexpensive cellulose wastes: paper, wood pulp, sugar cane, animal manure, and corncobs.

In Europe 25 million tons of special food, made from six tons of soybean and fishmeal protein, is consumed annually by hogs. Proteins manufactured by microorganisms could represent two million tons of complementary food per year.

There is still much work for the microbes; we have hardly begun to explore the many avenues opened by the bioindustry. By taking advantage of the techniques of genetic engineering, fermentation, and automatic selection of bacterial strains, we shall be able to custom-produce microbes to perform special tasks such as the elimination of oil spills on the surface of the oceans, the production of biological light, and the manufacture of specialized pharmaceutical products.

The Domestication of Enzymes

The enzymes are the agents responsible for the specificity and the efficacy of the microbes. The domestication of these catalysts by the bioindustry opens the way to new forms of chemical transformation. We have already seen results in the pharmaceutical and food industries, in medicine, and in the use of new instruments for biomedical analysis.

In large part enzymes owe their catalytic properties to their "active site." The particular spot on the body of the enzyme where reactions occur at high speed depends on the tridimensional structure of the enzyme.[12] Thus the preservation of this structure is fundamental to enzyme activity. (This is why enzymes are so fragile.)

The ultimate goal of numerous researchers is to be able to synthesize artificial enzymes--or simply to copy, with the help of the appropriate molecules, the activity of the active site. The first synthesis of an enzyme was done in 1969 by research chemists at the Rockefeller Institute and by the drug manufacturer Merck Sharp & Dohme. Today there is automated machinery for making synthetic enzymes, but the mass production of custom-made enzymes for industrial or medical use has yet to be achieved. As nothing opposes this automatic synthesis, it should become an industrial reality in the near future.

The major conquest of the bioindustry and its most promising direction for development are in the field of immobilized enzymes. or insoluble enzymes ( see notes ). For some time the food and pharmaceutical industries have used "free" enzymes (enzymes in solution) in particularly delicate chemical reactions.

Using techniques borrowed from chemical engineering, we can now bind enzymes on plastic supports or enclose them in microcapsules. The activity of the enzymes is thus enhanced. Moreover, immobilized enzymes are reusable; they enable the reactions to take place continuously and over long periods of time.

A whole field of new applications of immobilized enzymes is opening up: the production of amino acids by treating a mixture of these acids with enzymes that selectively destroy one of two isomers, thereby isolating the desired one; the transformation of plant syrup dextrose into the fructose used in producing sweets and nonalcoholic drinks; and the selective hydrolysis of starch or cellulose molecules.

In the near future we foresee the manufacture of biochemical electrodes that will make possible biomedical measurements of high precision as well as the creation of instruments of analysis. Very small artificial kidneys can be made from immobilized urease. The treatment of tumors and metabolic disorders can also be studied with the help of immobilized enzymes.

The know-how gathered over the years in chemical engineering and in process control can be applied today to reactions implementing immobilized enzymes. The consequences of this transfer will be determining factors in the development of the bioindustry.

Instead of using immobilized enzymes, one can try to copy the activity of the catalytic site of the enzymes. This site is usually composed of a

metallic ion (iron, zinc, magnesium, or molybdenum) surrounded by a molecular chain containing specific groups of amino acids. The discipline which studies the catalytic activity of complexes formed by both metals and organic molecules is bioinorganic chemistry. We can expect great contributions to the development of the bioindustry from this new field.

Scientists have been able to accomplish the synthesis of bioinorganic complexes with iron, sulphur, molybdenum, and specific amino acids capable of simulating the nitrogenase enzyme that transforms nitrogen in the air into ammonia. Nitrogenase is so effective that just a few kilos-- representing the total quantity of the enzymes present in all the nitrogenfixing bacteria and algae in the ecosystem--is sufficient to transform millions of tons of nitrogen into ammonia annually. One can understand the interest in artificial catalysts; capable of functioning in very mild conditions, they offer radically new solutions to the energy and food crises.

Controlling Fermentation and Photosynthesis

Another very promising domain of the bioindustry involves the electronic control of fermentation reactions.

Fermentation is the oldest energy reaction among living things. From microbes to men, it provides either a part or the whole of the energy that serves to maintain the biological organization. The most primitive organisms survive and develop by fermenting (in the absence of oxygen) the organic substances they extract from their environment. The techniques of electronics, data processing, and automation now provide engineers with ways of helping microbes in their fermentation reactions and making their work more efficient, in the hope of accomplishing a number of tasks useful to society. The basic method is to place the microorganisms in a fermenter and to furnish them with the elements they need to grow and develop, while automatically controlling the physical and chemical conditions of their environment. Computers help to determine and maintain the optimum conditions for the reactions: nutrients, acidity, concentration of carbon dioxide, elimination of wastes, and so on.

This system presents a curious and interesting symbiosis between man, computers, and microbes. Man obtains substances useful to his survival and development (such as drugs and proteins) and in return supplies the microbes with food and optimum conditions. The computers record, compare, and regulate the multitude of intermediate parameters typical of biological reactions, each of which possesses its own characteristics. This symbiosis is highly significant; it foreshadows the efficiency of the bioindustry of tomorrow and the perfection of electronic control necessary to the increase in productivity of our new microscopic slaves.

At a time of energy and environmental crises, one of the most useful biotransformations is the conversion of organic matter (from garbage, for example) to combustible gases, especially methane. The usual byproducts of bacterial fermentation are carbon dioxide and methane (see p. 8), and the quantities produced are significant. In 1973 the one hundred largest cities in the United States produced 74 million tons of solid wastes. If these wastes had been converted into combustible gases, they would have provided a volume of methane equal to 3 percent of the total demand for natural gas in the United States. The biological production of methane can now be considered a complementary source of energy, one that offers to do away with significant quantities of garbage.

The domestication of photosynthesis reactions, toward which many laboratories around the world are working, will also have a determining effect on the development of the bioindustry. The ideal solution would see the production of energy-rich substances from the sun, carbon dioxide, water, and chlorophyll. Despite the rapid gains in knowledge in this area, however, we are still far from making a catalytic unit capable of reproducing the efficiency of the chloroplast in leaves. Intermediate solutions are nonetheless possible. Sugar cane, for example, produces the best photosynthetic yield of all known green plants. We should make greater use of it as an industrial raw material in the production of alcohol and ethylene and various carbon products. The hevea, too, is an efficient producer of carbon chains that could be used as a source of hydrocarbons.

Finally, chemical reactions which took place on the primitive earth billions of years ago can serve as models to the bioindustry. From simple gases (methane, ammonia, water vapor, hydrogen), under the effects of ultraviolet rays and in the presence of mineral catalysts, considerable masses of organic material were manufactured in the upper atmosphere and accumulated in the oceans. The first living organisms evolved from this reserve of material and food. Today the chemical industry, particularly in Japan, knows how to benefit from these "prebiotic" reactions in the manufacture of the raw materials used in making drugs. In this way the bioindustry could take advantage of the mild and natural reactions of prebiotic chemistry by channeling them toward the production of foods and pharmaceuticals.


The methods, reactions, and processes described above, like the bioindustry itself, are all part of a much larger body of techniques and skills. This domain will dominate the end of this century and the beginning of the next, just as mechanical engineering and then electronics have

dominated the last fifty years. I call this assembly of techniques ecological engineering, or ecoengineering.

Ecoengineering is much more than ecological development, management, or planning. Reaching beyond the management of nature, it recognizes the symbiotic nature of the relationship between human society and the ecosystem, wherein each uses the other to their mutual benefit. Ecoengineering, with the help of new methods like energy analysis, will enable men for the first time to control consciously the energy circuits of the ecosystem for the good of man and nature.

Like doctors or surgeons working in the very interior of the organism, we shall be able to reestablish the great feedback loops of reward and reinforcement on which the "economy" of nature is built. We shall have to close in, reconnect, and even "naturalize" the chains and networks of the socioeconomic system (such as those that eliminate wastes and produce food). We shall be able to develop new bacterial strains capable of helping us to effect a more efficient recycling of used materials and elimination of waste. We shall have to achieve the large-scale transformation of nitrogen into ammonia in order to feed the world population. We shall have to modify climates locally to provide new areas for cultivation and to help nature readapt to the aggressions to which we have subjected her.

With the advent of ecoengineering, the dangerous experiments of those of us who are sorcerers' apprentices will cease. Only then shall we be able to develop a partnership between man and nature, the basis for a new postindustrial economy ( see notes ) and society that we shall have to create from scratch.

[1] See also the diagrams of the history of the economy ( see figure 11 on page 14, figure 12 on page 14 , figure 13 on page 15 , figure 14 on page 16 , figure 15 on page 17 , and figure 16 on page 18 ).

[2] I shall consider here only the thermodynamic and statistical aspects of entropy. The relationship between information and entropy is treated in the following chapter on information.

[3] The identification of flow and force in social and ecological systems is quite recent. Ecologists like Howard Odum are responsible for having identified it in a large number of processes.

[4] The kilocalorie is one thousand times greater than the "small calorie," or the quantity of energy needed to raise by one degree a cubic centimeter of water at 15deg. centigrade.

[5] There are about 20,900,000 active persons working an average of 173 hours per month.

[6] Specific kinds of pollution are those caused by carbon monoxide (CO), sulphur dioxide (SO2), and nitrogen oxide (NO), one might also include water pollution, solid wastes, radioactive wastes, and thermal pollution of the rivers. Norms and standards established by governments and international organizations generally apply to these types of pollulants

7 A definition of free energy is given in the note ( on page 116 ).

[8] The value addded of a product is the difference between the final value of the product and the value of all the materials used in its manufacture

[9] Unlike energy, free energy, or thermodynamic potential, introduces a quantitative expression of the desirability of a product. For example, the value of an iron ore is higher when the ore is rich in iron than when the ore is diluted a thousand times in dust. The difference between energy and thermodynamic potential brings in entropy, that is, entropy multiplied by the absolute temperature of the transformation.

free energy= energy--entropy X absolute temperature

[10] In 1978 a team of scientists in California succeeded in a formidable task: an artificial gene coding for insulin was inserled in E. coli, which started to produce small quantities of the precious hormone. However, as promising as they are, these techniques represent new dangers for mankind. For this reason biologists have decided to apply the strictest security measures with respect to this type of genetic manipulation.

[11] A 500-kg steer may yield -1/2-kg protein per day. The corresponding figure for 500 kgs of microbes is 5 tons per day.

[12] See the function of hemoglobin ( on page 53 and below ).