Energy and the Ecological Economics of Sustainability

By John Peet

Energy and the Ecological Economics of Sustainability examines the roots of the present environmental crisis in the neoclassical economics upon which modern industrial society is based. The author explains that only when we view ourselves in the larger context of the global ecosystem and accept the physical limits to what is possible can sustainability be achieved.

• Language: English
• Publisher: Island Press
• Release date: Apr 10, 2013
• ISBN: 9781597269131

John Peet

John Peet is Europe Editor at The Economist, where he has previously been Business Affairs Editor, Brussels Correspondent and Finance Correspondent. Before joining The Economist he was a civil servant, working for the Treasury and the Foreign Office.

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About Island Press

Island Press, a nonprofit organization, publishes, markets, and distributes the most advanced thinking on the conservation of our natural resources—books about soil, land, water, forests, wildlife, and hazardous and toxic wastes. These books are practical tools used by public officials, business and industry leaders, natural resource managers, and concerned citizens working to solve both local and global resource problems.

Founded in 1978, Island Press reorganized in 1984 to meet the increasing demand for substantive books on all resource-related issues. Island Press publishes and distributes under its own imprint and offers these services to other nonprofit organizations.

Support for Island Press is provided by Geraldine R. Dodge Foundation, The Energy Foundation, The Charles Engelhard Foundation, The Ford Foundation, Glen Eagles Foundation, The George Gund Foundation, William and Flora Hewlett Foundation, The Joyce Foundation, The John D. and Catherine T. MacArthur Foundation, The Andrew W. Mellon Foundation, The Joyce Mertz-Gilmore Foundation, The New-Land Foundation, The J. N. Pew, Jr. Charitable Trust, Alida Rockefeller, The Rockefeller Brothers Fund, The Rockefeller Foundation, The Florence and John Schumann Foundation, The Tides Foundation, and individual donors.

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© 1992 John Peet

All rights reserved. No part of this book may be reproduced in any form or by any means without permission in writing from the publisher: Island Press, Suite 300, 1718 Connecticut Avenue NW, Washington, D.C. 20009.

Library of Congress Cataloging-in-Publication Data

Peet, John.

Energy and the ecological economics of sustainability / John Peet.

p. cm.

Includes bibliographical references and index.

9781597269131

1. Environmental policy—Economic aspects. 2. Human ecology. 3. Thermodynamics. 4. Paradigms (Social sciences) I. Title.

HC79.E5P42 1992

333.7—dc20

91-41207 CIP

Printed on recycled, acid-free paper

e9781597269131_i0002.jpg

Manufactured in the United States of America

10 9 8 7 6 5 4 3 2 1

To my parents and your parents

To my children and your children

To their children, and their children’s children

Table of Contents

About Island Press

Title Page

Copyright Page

Dedication

Preface

Acknowledgments

Part I - NATURE

1 - Energy in Nature

2 - The Scientific World View

3 - Energy—A Scientific Perspective

4 - The Political-Economic World View

5 - The Systems Approach

6 - The Biophysical Systems World View

Part II - LIMITS

7 - The Physics and Morality of Growth

8 - Feedbacks and Externalities

9 - Myths of the Political-Economic World View

10 - Myths of Science and Energy

11 - Ecology versus Exemptionalism

12 - Humanity Separated from Nature

Part III - CHOICES

13 - Values for a Sustainable Future

14 - Energy for a Sustainable Future

15 - Sustainable Development

16 - Ecological Economics

17 - With People’s Wisdom: Stewardship and Sufficiency

Conclusion

Appendix - The Venice Declaration

Notes

References

Index

About the Author

Also Available from Island Press

Island Press Board of Directors

Preface

Many people feel that humankind is on the verge of major changes; it seems to be the end of one age and the beginning of another. To many, it seems planet Earth and all living things on it are being treated by societies as if there were a new planet parked alongside, ready to step onto.

In order to look at ourselves and our planet more clearly, I believe it is important to learn to use some important, yet little-understood, tools of science to enable us to gain insight into the events that face us. These tools, especially the part energy plays in the world as seen through physics and ecology, enable us to look at what is happening from viewpoints very different from those that are normally available. What we want to do is always, and always will be, limited by what we can do. If we can be guided in our decisions by what we can do, we will choose those options that we think we can work toward, rather than always assuming that technology will come to the rescue.

In writing this book, I have attempted to clarify a number of policy issues that face us, as people and as societies, as we move toward the end of the twentieth century. To do so, I have set out my case in three main parts.

In part one, I describe some important tools that are available from physics and ecology. Most of them have been available for a long time—more than a century in some cases—but are still only dimly understood by most decision makers. The tools I describe lead us to a biophysical systems understanding, which explains some very important aspects of what is happening in the world. The understanding we gain from use of these tools differs markedly from an understanding built on scientific and economic understanding, which was part of the schooling of most of those currently in positions of power in government and commerce. In particular, the tools I describe help us understand that the environment is the playing field on which all other social concerns compete.

In part two, I turn to areas influenced by misconceptions and conflicts of opinion—for example, whether there are limits to the growth of an economy. The common view is that all things are possible, but in fact there are laws of nature, such as the second law of thermodynamics, that give us precise statements of processes that are absolutely impossible. Classical physics, even after Einstein, could conceive of a supreme mathematician who would possess the super formula to describe all of nature. Modern physics, on the other hand, suggests that in the long term, nature actually works via random, irreversible processes, not deterministic, reversible ones. Nature is generally not predictable, nor are the development paths of human societies.

In part three, I have attempted, so far as is possible, to reflect my feelings about answers to important questions gained from more than twenty years of working on energy, environmental, and related public policy matters in industry, at a university, and in citizens’ groups. I am convinced that the problems that face us as we move through the closing decade of the twentieth century are not being adequately solved by methods derived either from political economics or from the natural and physical sciences, used alone. A new way of looking at the world—a new image—must be constructed, from tools that may be beaten out of the old tools but that have a shape and function quite unlike the old. I and others use the term ecological economics for the approach that we believe is needed.

We do have the choice to invent our own future, but if we do not take up that choice, the future will be shaped for us, with tools that were made in the past and that are largely irrelevant today.

The question What sort of future do we want? should be answered by everyone, but this will be possible only if people are empowered to do so, by having access to as comprehensive a picture as possible. We need the wisdom of everyone in society, especially people who have been alienated from normal decision-making processes by institutional structures that support the status quo and the powerful. We will not be able to use that wisdom unless we have a society in which experts accept that it is their function to assist people to gain the power to make their own decisions rather than to help the powerful make decisions for everyone else.

Why did I write this book? My aim was to promote the ideal of a just, peaceful, compassionate, and sustainable society that recognizes that there will be approximately 6 billion people in the world by the year 2000. The means was to describe perspectives and tools that might assist people to make choices consistent with the transition toward such a society, in preference to alternatives that promise destruction or degradation for humanity and for nature.

Acknowledgments

I have had an enormous amount of help from many people over the years, and I would like to thank them.

Five in particular have guided me through some of the mine fields. Over the years, I have met and learned directly from Herman Daly, Kenneth Denbigh, Howard Odum, and Malcolm Slesser. I have learned a great deal indirectly from the writings of Nicholas Georgescu-Roegen.

Of my friends and colleagues in Aotearoa–New Zealand, I must make special mention of James Baines, with whom I have worked for several years. Valuable contributions to my understanding have been made by Louis Ar-noux, Geoff Bertram, Graeme Britton, Garth Cant, Paul Dalziel, Kelly Duncan, Brian Earl, Brian Easton, Murray Ellis, Bob Entwistle, Evelyn Entwistle, Jeanette Fitzsimons, Chris Harris, John Hayward, Charles Hendtlass, Molly Melhuish, Martin O’Connor, Gordon Rodley, Basil Sharp, Jim Stott, Cath Wallace, Arthur Williamson, and Janice Wright.

Friends in the international Balaton Group have also given me a great deal of help, and their insights have expanded my horizons considerably. Bert de Vries, Dennis Meadows, Donella Meadows, Richard England, Neva Goodwin, Thomas Johansson, Jane King, Ulrich Loening, Niels Meyer, Jorgen Norgard, Ironer Revi, Chirapol Sintunawa, John Sterman, and Qi Wenhu are members whom I would specifically mention as sources of material used in this book, but all have helped me enormously.

Support from the New Zealand Energy Research and Development Committee was valuable in giving me the resources to develop some of the data sources used as background. My friends in the Sustainable Energy Group, in Engineers for Social Responsibility, and in American Engineers for Social Responsibility also gave me valuable support when I needed it. The many students who carried out projects under my guidance often taught me more than I taught them, and I am very grateful to them.

If I have inadvertently reproduced too many of the views and/or expressive writings of these (and any other) good people, I apologize and hope they accept it as a compliment!

My partner, Katherine, and our children, Amanda, William, and Ben, have given me a great deal of encouragement, support, and love during a time when it often appeared that I was with them in body but not in spirit. Katherine’s help in several areas, especially in chapter 17, has been of key importance.

Part I

NATURE

The World as We See It

1

Energy in Nature

THE WORD ENERGY is used widely, but often in ways that inadequately reflect its deeper scientific meaning. For the moment, let us regard it as a property of matter that enables us to describe why physical and chemical transformations occur. (I discuss its meaning in more detail in chapter 3.)

The word nature has a number of meanings, but most people see nature as that which is living: soil, plants, trees, animals, birds, fishes, and so on. In the Western tradition, the word’s connotations derive from the idea that man is separate from the rest of the environment.¹ Nature is that which is alive, but not human, and of no value until man takes hold of its resources and transforms them into usable things. This ideology has been a powerful force behind the dominance of the Western tradition over the past few centuries. Most other cultures see humans as an integral, inseparable part of the natural environment.

In this book, I use nature to encompass everything in the environment of planet Earth, but with particular reference to the domain of living organisms in the sea, land, and air. In this perception, humankind is obviously part of nature, not apart from her.

EARTH AND SUN

The sun is the source of energy for almost everything that happens on earth. The nonrenewable stocks of fossil fuels, coal, oil, and gas in most economies come from the remains of plants and animals that lived millions of years ago, absorbing solar energy as they grew and reproduced. Renewable energy sources, such as water in mountain lakes and rivers, wind, and waves, result directly from the action of the sun on the earth’s atmosphere.

To put the sun and the earth into their wider context—the physical universe—let us look briefly at current ideas of how they came into being.

HOW IT ALL BEGAN

Theories as to the origin of the universe—like many scientific theories—have gone through major changes over the past hundred years. The main impetus for the changes has been the realization that creation accounts, common to many cultural and religious traditions, need to be reinterpreted in the light of the scientific discoveries of this century. The reason why the biblical accounts of creation (Genesis 1 and 2, for example) have been reinterpreted is not that these ideas are wrong. Rather, they were written as part of a cultural-historical framework of belief, expressed in the language of imagery. They should not be seen as scientific explanations of a cosmic physical process. Thus, the truth of accounts of creation, from no matter which great religious tradition, should not be judged by the methodology of science; they are myths with spiritual and religious meaning. As such, they stand separate from scientific theories and should not be compared with them.

Currently, the most widely accepted scientific theory is that the physical universe originated in a cataclysmic event (the big bang) some 10 to 20 billion years ago.² The primeval building blocks of all the matter-energy of the universe started off concentrated into an unbelievably small, super-hot fireball. This then exploded, flinging its contents out into space.

In the sense in which the terms are used here, matter and energy are not really distinguishable from each other. This is why we use the term matter-energy. Under the extreme conditions of a big bang, temperatures would be of the order of a million million degrees: so hot that even electrons, protons, and other elementary particles could not exist independently. Although that initial state lasted for only a small fraction of a second, these conditions indicate that in the beginning the universe could be regarded, in a sense, as pure energy, much of which subsequently changed into matter.³

Subsequent cooling then produced gases, which over billions of years aggregated into condensed masses and eventually formed the first stars. Many of these stars generated so much heat (from gravitational collapse and their own radioactivity) that they exploded again. This process may have occurred several times and may be going on today in some distant part of the universe. It is believed, for example, that our sun is probably a fourth-generation star.

The physical universe owes its nature and structure to that initial process. The theory tells us nothing, however, about what happened before the big bang. Indeed, the question of whether even time and space existed before that event cannot be answered unequivocally

Stars are usually too hot for simple molecules to form in them—their high energy levels ensure that atoms that come together to form molecules are immediately flung apart again. Formation of a variety of stable molecules results from cooler conditions that may be found in regions some distance away from the stars. Our solar system was probably formed around 4.5 to 5 billion years ago from a huge cloud of interstellar dust that came together as a result of gravitational attraction. The earth is thought to have condensed out of a part of the cloud that contained a diversity of elements, especially those necessary for the development of life.

LIFE ON EARTH

It is not known how life began on earth. One hypothesis is that spontaneous generation of simple life forms occurred in a primeval soup of hydrogen, ammonia, methane, carbon dioxide, hydrogen sulfide, water vapor, and other simple gases formed from combinations of the lighter atoms. These could have been present soon after the earth cooled enough for them to be formed. Lightning discharges could have provided the energy needed to trigger chemical combinations, giving rise to elementary life forms.

Another hypothesis is that on the tiny dust grains in interstellar clouds, conditions may have been conducive to the formation of the building blocks of life. These grains, diffused over the universe and aggregated into meteorites and comets, may have served as seeds for the generation of life here. If correct, this theory also suggests that such a process may have occurred elsewhere in this galaxy and others.

Yet another hypothesis suggests that in some situations, there were minerals (probably clays) with complex surfaces to which simple molecules may have become attached. Under certain circumstances, the attached molecules could undergo reactions with adjacent ones to form larger, more complex molecules, which could have been precursors of the first simple organisms.

Whichever hypothesis eventually turns out to be correct, the important thing is that life has apparently existed on earth for several billion years and that over this time there has been a process of evolution, with more and more complex forms of life coming into existence.⁴

The initial life forms came into being around 3.5 billion years ago. They were probably one-celled bacteria existing in water, perhaps close to seashores. Single-celled algae came on the scene about 2 billion years ago. These organisms did not breathe oxygen, because free oxygen was not present in the atmosphere in those early days. However, they produced oxygen as a result of their activities, excreting it as a waste product into the water in which they lived. Over millions of years, oxygen built up in the seas and in the atmosphere until, about 1 to 2 billion years ago, it reached today’s level of 21 percent, at which it has stayed reasonably constant. ⁵

After the oxygen level settled down, evolution quickened. Simple cells gave rise to more complex cells and multicellular organisms. Sexual reproduction introduced a vastly greater range of genetic combinations, in turn increasing the likelihood of successful development of new organisms. In time, life forms came into existence that were able to feed off other life forms. Instead of having to make their nutrients from minerals and gases via the photosynthesis process driven by light energy, these more advanced forms could obtain them ready-formed into the amino acids, carbohydrates, and so on manufactured by simpler organisms. They then had a competitive edge and were able to develop faster as species.

Over time, more and more specialization occurred. Plants developed from simple organisms and in turn provided a food source for animals. About 450 million years ago, plants began to colonize the land. Animals followed them about 50 million years later.

The processes of evolution did not take place in a continuous manner. Evolution apparently occurred in jumps, with long periods of relative stability in between. Sudden transitions after long periods of stability may have occurred due to changes in the environment, perhaps from climatic factors (ice ages, for example), volcanic activity, or meteorite impact.

The awesome complexity of life on earth is the result of hundreds of millions of years of development. How the process started is a matter of great interest, but in some respects it is largely irrelevant to the questions that face us today. The most important group of questions relates to the power of humanity to make choices (especially about survival), not only for itself as a species but for virtually all other life forms as well.⁶ In order to understand more about where we humans are going, we need to know not only where we have come from but also where we are now. We do this by looking first at the place of energy in the natural environment.

ENERGY FLOWS TO EARTH

In the general sense, life on earth (including virtually all activities of human societies) stems, directly or indirectly, from the sun. The sun is the source of effectively all of the energy available to the solar system. The earth is a consumer of some of the sun’s energy in that energy absorbed from the sun is used to drive atmospheric and life processes before being rejected to the cosmic heat sink of outer space. The radiant energy received from the sun supplies heat to the earth’s surface and light for the processes of photosynthesis in plants. The complex hierarchy of animal life depends on these flows of energy, from the simplest organisms to the giants of the forest, from bacteria to humans.

Energy from the sun heats the sea and the land, thereby creating convection currents in the atmosphere that result in air movements, evaporation of water from the sea, and rain. Table 1.1 gives data on some of the paths taken by incident solar radiation in the earth’s atmosphere. It also shows the approximate percentages of the total incident solar energy traveling along each path.⁷

From these data, for each solar constant joule (SCJ) (units of energy are described in chapter 3) of solar radiation that reaches the outer atmosphere, 53 percent never reaches the earth’s surface. Of the remaining 48 percent, 34 percent falls on the oceans and 14 percent falls on the land.⁸

When energy takes part in activities at the earth’s surface, some of it is always degraded into low-temperature heat. This heat is ultimately lost from the earth’s system by long-wavelength (infrared) radiation into space. A small part of that energy may be stored for a time, either as plants and animals or as fossil fuels. Eventually, even these will be degraded into low-grade heat, but modern societies are accelerating the process by using the reserves at a rate vastly greater than their formation by natural and geological processes. In this context, accelerated global warming, forest death, and damage to the ozone layer testify to the limited ability of the earth’s ecosystem to absorb wastes.

TABLE 1.1 Paths Taken by Incident Solar Radiation

ENERGY AS THE BASIS FOR LIFE

The main energy pathways shown in table 1.1 are the energy supply for the environment within which life exists, but they do not directly involve living things as such. To incorporate the activities of living organisms into our picture, we need to look in more detail at solar radiation as the energy source for biological photosynthesis in plants.

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FIGURE 1.1 Energy Flows in the Growth of Plants. a, incoming solar energy slow; b, embodied energy of the new biomass (plant matter) created as a result of the photosynthesis transformation process; c, embodied energy in the biomass (e.g., leaves) used to intercept incoming solar energy; d, heat energy dissipated in the photosynthesis process; e, heat energy dissipated from the plant in other metabolic processes (e.g., growth and maintenance).

The majority of plants obtain most of their energy from the sun in the form of light. Together with chlorophyll, light energy enables the manufacture of food and other materials needed for plant maintenance and growth, from the carbon dioxide in the air and from other nutrients obtained from the soil via root structures. In a sense, energy is embodied in plant tissue as it grows, in that energy and matter combine to create more complex structures than those of the food taken in. Figure 1.1 shows this process in diagrammatic systems form, with a store of plant matter (biomass) being built up as a result of interaction between incoming energy from the sun and existing plant matter, such as leaves. Energy is continually being degraded to low-temperature heat.

Figure 1.1, which shows only the energy flows involved in overall plant growth, is, of course, heavily simplified. Nevertheless, energy flow is a critical element in such systems, and a great deal of important information and deep insight may be gained by consideration of flows of direct and embodied energy. Embodied energy flows provide a unique means of following processes and systems in nature and in society.

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FIGURE 1.2 The Growth of Stored Plant Biomass

The growth process depicted in figure 1.1 may also be represented on a graph to show how the size of the embodied energy store (the biomass) changes with time. Figure 1.2 shows how the size of a plant increases slowly at first, then at an accelerating rate. Known as exponential growth, this pattern is typical of the early stages of growth in many systems (see chapter 7). It is an example of a positive feedback system, in which growth reinforces itself (see also chapter 5). Such processes cannot go on forever, of course, since they will in time be limited by the rate of energy flow available (usually from the sun). Eventually, after the plant’s essential needs for its own maintenance have been met, a stage is reached at which no surplus energy is available for growth. The system then settles down to a more or less constant level (represented by the dashed section of the growth curve). The growth curve as a whole, known as a logistic curve, is typical of the long-term behavior of all ecosystems and many other systems.⁹

FOOD CHAINS

Plants, on land and in the sea, are food for many animals (herbivores) and small fish, which in turn are food for flesh-eating animals and larger fish (carnivores). The energy flows that enable plants to grow are the basis for the whole web of life.¹⁰ Although a large quantity of plant matter is needed to feed one herbivore and a large quantity of herbivores is needed to feed each carnivore, only part of the solar energy embodied in each kilogram of plant matter eventually ends up in the carnivore as tissue (muscle, bone, etc.). This is because energy is always lost at each stage in the process (more correctly, it is degraded into an unavailable form—see chapter 3) and is rejected into the surrounding environment. When animals die, their remains decompose and fertilize the growth of biomass. Animal dung has a similar function.

In such a chain, embodied sunlight is progressively concentrated through each successive transformation process. At each step in the chain, the output can be described as being of energetically higher quality, because it has more embodied energy per unit of organism. In short, more embodied energy is required to keep a carnivore alive than to keep an herbivore alive. This is not surprising, since a consequence of this increase in embodied energy is that the total quantity of organisms in each stage is very much less than in the previous one. Thus, a very large quantity of soil is required to support a large quantity of plants, which in turn support a much smaller number of insects, a yet smaller number of birds and rodents, and so on, up to the level of the higher carnivores. This way of looking at things uses the image of the pyramid.¹¹ Lines of dependence for food and other services within the pyramid are what we have already referred to as food chains. The pyramid as a whole is a tangle of food chains—the higher and more complex the pyramid, the more evolved is the ecosystem that it models.¹²

An example is a food chain comprising grass, grasshoppers, frogs, trout, and humans.¹³ At each stage of the chain—when the grasshopper eats the grass, the frog eats the grasshopper, and so on—there is a loss of energy. In the process of consuming food, most animals lose about 90 percent of the food energy to their surrounding environment as low-temperature heat and as dung. Only around 10 percent of the food energy remains embodied in the tissue of the eater, for transfer to the next stage of the food chain. In our example, the pyramid involves around 1,000 tons of grass to feed 27 million grasshoppers, which feed 90,000 frogs, which feed 300 trout, all to sustain 1 human for a year.

Every living thing maintains its structure at the expense of an enormous dissipation of energy into the surrounding environment. The biologist A. J. Lotka pointed out that organisms are designed to be collectors and transformers of energy. If they do not do so, they will not survive. That they do so more often in cooperation with other members of the ecosystem than in competition with them is well known to most ecologists. ¹⁴ Regrettably, it is becoming very clear that humans, at the apex of the pyramid, demand so much of the earth’s production (about 40 percent)¹⁵ that other life forms are in jeopardy.

THE MAXIMUM POWER PRINCIPLE

In the context of evolution, Lotka argues that those systems that survive in the competition among alternative choices are those that develop more power inflow and use it best to meet the needs of survival. ¹⁶ This statement, often referred to as the maximum power principle (MPP), means that natural selection tends to favor organisms that maximize the flow of energy. The rate of flow of energy (the energy flow per unit of time—for example, joules per second) is what we call power.

If an organism can maximize its flows of energy, it will grow faster than competitors that do not. Once it is larger than they, it commands greater resources, can use yet more power, and can grow even faster. The importance of using that energy inflow efficiently (in order to satisfy the MPP’s requirement to . . . use it best to meet the needs of survival) is illustrated by the example of a plant that grows fast but does not put down good roots in case of a drought. Alternatively, if it devotes its energy to putting down deep roots, it risks being cast in the shade by a competitor.¹⁷ The need to achieve a balance is part of the process of survival of the most fitting that characterizes nature. Most importantly, that process often is one not so much of ruthless competition as of cooperation, with organisms maximizing power jointly rather than individually.¹⁸

ENERGY AND GROWTH

In the early stages of biological growth (figure 1.2), most energy goes into growth and little goes into maintenance. With maturity, the balance changes, until most inputs are required just to maintain the system. At maturity, there is what appears to be nonproductive growth, although this is needed to maintain and renew the fabric of the system and ensure its health.

The MPP is quite a good model for describing the early stages of an ecological system’s development when there is a surplus of energy. In such a system, organisms (initially plants) must compete ruthlessly and grow fast in order to gain a toehold. After the initial, colonizing, stage of habitat occupation, there is an increased quantity of organisms, so they have to adapt to the limited energy flow available to them by using it more efficiently. Sooner or later, all ecosystems stop growing because of inescapable physical limitations to the flow of energy, whether this be in the form of sunshine or of stored food reserves within organisms. ¹⁹

In nature, the fast-growing species that dominate the growth phase tend to be overtaken by more adaptable species that can survive shortages or changes in availability of food and energy and can maximize their own flows when energy is difficult to find. This later stage generally results in greater complexity and range of organisms than in the colonizing stage. Often, many of the initial colonizers are replaced by later, more specialized arrivals.

Energy is used by an organism primarily as the means whereby the processes of life are fueled. Without energy, life could not exist. Nutrients are important both for their matter and for their energy content. Matter can be recycled in an ecosystem, but energy is always degraded in use and can never be reused in the same form without expenditure of more energy (see chapter 3). The use and recycling of matter are part of the natural life system, with energy needed at all times to drive these processes. This is why the concept of embodied energy is such a valuable means of studying complex systems in the living environment.

POPULATION GROWTH DYNAMICS—R- AND K-SELECTIONISTS

The growth dynamics of populations of organisms are of great importance in helping us understand some of the characteristics of ecological systems. The growth dynamics of some animal species—insects especially—are such that their populations boom during good times and collapse rapidly when conditions are not so good.²⁰ These r-selectionists have short breeding cycles; parent animals produce large numbers of offspring (e.g., in the millions); and the young are given no parental care. Such species rapidly populate an area where food, climate, and so forth are favorable, but they may be unable to maintain their numbers after only small changes in their environment.

The other main type of population growth is that of the k-selectionist, in which the population grows slowly, parental care is given, and the animals are generally more versatile in their ability to survive in times of change in their surrounding ecosystem. The larger mammals, including humans, are in this category; they tend to grow until they are in a steady state with their surroundings. At that time, their population is more or less constant, reflecting the logistic type of relationship in figure 1.2.

Many natural systems adopt a dynamic characterized by pulsing, in which populations of one type of organism may grow at some times and decline at others, allowing their surrounding ecosystems to recover in the meantime.²¹ Pulsing is one possible explanation why both r- and k-selectionist mechanisms appear to be successful in their separate ways. It may also, in the social context, be a possible explanation for business cycles.

Conventional economies, capitalist and socialist, encourage r-selectionist behavior in that their socioeconomic messages encourage a maximum growth rate as the primary criterion of