April 3, 1973
Page 10773
THE IMPACT OF GROWTH ON THE ENVIRONMENT
Mr. MUSKIE. Mr. President, on April 2 and 3 of this week, the subcommittee on Air and Water Pollution initiated a series of hearings on the impact of growth on the environment.
Of particular interest and importance was testimony presented to the subcommittee by Dr. George M. Woodwell of the Brookhaven National Laboratory on the "Ecological Effects of Growth."
Dr. Woodwell has made a significant contribution to identification of the impact of man's activities on the world's life support systems. His conclusions are provocative and significant. He challenges many of the assumptions on which our industrial-technical society has functioned for the last 100 years.
Three specific conclusions which Dr. Woodwell has drawn highlight the importance of his commentary:
1. The assumption that the environment has an assimilative capacity for all human insults is misleading and inconsistent with the imperative that the earth's biota be preserved for continuous use by man. An assimilative capacity for organic matter or heat does not imply an assimilative capacity for mercury, lead or other substances that may accompany the organic matter. The evidence is overwhelming that man has already exceeded the assimilative capacity of the biosphere for CO2, chlorinated hydrocarbon pesticides, PCB's, dust and possibly fossil fuel energy. Assimilative capacity is a useful concept only within those areas of the earth that man determines that he will manage intensively.
2. Economic principles are an insufficient basis for management of the biosphere or such large segments of it as the United States controls. The limits of the earth can be accommodated by recognition of the fact that the biosphere is a series of interacting units, oceans, forests, estuaries, cities, agricultural units, each of which has definable characteristics including interactions with other units. Some such as the oceans, cannot be managed intensively; other such as cities and agricultural regions, must be. The design and management of these units is an essential topic for science and government. It is encouraging that our laws are now beginning to reflect in their objectives some of the realities of the biosphere.
3. The pattern of change necessary in the design of human activities is clear. The further diffusion of toxic influences around the globe must be checked. A certain amount of retrenchment and repair is necessary to assure the stability of biotic resources. Cities cannot be allowed to dispose of wastes in the oceans; fresh water supplies, nutrient elements and mineral resources are to be conserved and recycled; estuaries and coastal waters cannot be used for cooling power plants or usurped for other industrial uses: they are essential to maintenance of the oceanic biota, including especially the fisheries.
In order that my colleagues may study and react to this important contribution to understanding the impact of growth on our environment, I ask unanimous consent that the testimony of Dr. Woodwell be inserted in the RECORD.
There being no objection, the testimony was ordered to be printed in the RECORD, as follows:
ECOLOGICAL EFFECTS OF GROWTH
Many of the ramifications of growth have been explored recently in documents familiar to you such as "The Limits to Growth"(Meadows et al. 1972), "Blueprint for Survival" (Goldsmith et al., 1972) and Mishan's "The Cost of Economic Growth" (Mishan,1967). These documents establish that many facets of growth as we have known it through the past century will slow or stop within the next decades. The principal question is whether we will have any control over the transition, avoiding the discomforts of Malthusian limits or analogous chaos. I applaud your attempt to address the question directly.
I shall examine an aspect of the cost of growth that has not been explored adequately in these documents or elsewhere. This is the dependence of man on the earth's living resources. I believe that the data I shall summarize indicate that this dependence is far greater than the world's intellectual, political or economic leaders have commonly acknowledged, that irreversible changes are occurring at the moment that have great importance for all, and that, while significant steps have been taken recently in our own air and water pollution bills, much more powerful steps are needed to prevent major, irreversible changes in the capacity of the earth for support of man.
First, the problem is urgent, perhaps the very most urgent of the plethora of urgencies of our time. There is a common tendency to think of pressures on environment as directly correlated with the growth of population; and so they are. The population of the earth is expected to double in the next 30-35 years. But pressures on environment are also a product of human activities.
People who have cheap energy, for instance, can command more of the earth's resources than those who do not. Indeed, one of the advantages of having an abundance of energy is precisely this control over other resources. The aggregate demand on resources is the product of the number of people times their average impact per person. Various indices suggest that aggregate impact is increasing very much more rapidly than the population alone. A review of the "Gross Domestic Product", which does not include services, taken from the U.N. Statistical Yearbook (1968), shows an annual increase since 1950 of 5 – 6%, or a doubling time of 12– 14 years (SCEP, p. 119). The Gross Domestic Product might be taken as one index of the aggregate effect of man on environment.
Similarly, the amount of energy used in support of the technological segment of society is another index of aggregate demand on resources. World use of fossil fuel energy has increased for the last century at about 4% per year, giving a doubling time of about 18 years (Hubbert 1969).
Such considerations suggest that the aggregate effects of man on environment are doubling in between 1 and 2 decades, perhaps less. This is a very short time when we consider the time required for major changes in social systems.
Certain effects increase at much greater rates. In the 15 years between 1951-66 a 34% increase in food production was accompanied by a 146% increase in use of nitrates and a 300% increase in use of pesticides. These relationships are shown in Table 1. There appears to be every reason to believe that the further intensification of agriculture will require similarly disproportionate efforts, perhaps more so, as less fertile lands are put into production. There is reason, moreover, to fear that toxification of the environment over large areas will aggravate this problem significantly. It is difficult to exaggerate the speed with which these problems are developing or their potential for disruption.
Second, contrary to the arguments of many economists and others, the earth's biota is our single, most important resource.
While protecting it will not assure wealth and grace for man, its decimation will assure increasing hardship for all. We can gain insight by examining certain aspects of the earth's energy budget, including especially the nonbiotic energy used directly by man in support of technology and the energy used by plants in support of the essential qualities of that thin surface layer of the earth that contains all life. I use energy for my simplification because energy is the basis of the wealth of the western nations and, as we have seen, it can be used as an index of total human activity. I use it also because those who advocate reliance on growth as a solution for all problems rely on an abundance of cheap energy which can be used to substitute resources for one another as need arises. Energy can also be used to measure the intensity of biotic activity on a regional or global basis. A brief discussion and comparison of these two flows of energy, that through man-dominated systems and that through the earth's biota, provides an indication of the scale of human activities and offers one index of the limits of the earth for support of man.
First, world consumption of non-biotic energy is summarized for 1967 in Table 2. Total energy use worldwide, including all nonbiotic sources, was estimated as about 45x1019 KWH. Virtually all of it was from fossil fuels. About 35% of the total energy was used by the United States and about 86% by the "developed" countries. If all the people of the world used energy at the U.S. rate in 1967, total energy use would have been 6.6 times higher than it was then. Chauncey Starr, writing in the Scientific American in 1971, estimated that if the people of the underdeveloped countries were able to reach the present U.S. standard of living by the year 2,000, total world energy consumption would be 100 times the present consumption. This is, of course, impossible.
Petroleum is the most versatile form of readily available energy at present. M. K. Hubbert in 1969 provided an authoritative appraisal of world supplies, reproduced here as Fig. 1. By either of the two limiting assumptions as to the total quantity of petroleum on earth, we can expect to enter the declining phase of extraction and use world wide by the year 2,000 or sooner. A 6 fold increase in rate of use is not possible; the maximum use may be 2 times the present rate, but will decline almost immediately because of declining supplies. Coal is a very much larger resource and might sustain greatly increased use, but at substantial cost to environment in strip mining and in air pollution. Nuclear energy's potential is not being realized for a variety of important reasons.
Other non-biotic sources of energy are small. The possibilities for sustaining a doubling time of 15-20 years for energy use worldwide for more than another doubling look questionable at present simply on the basis of the size of the resources and the magnitude of the problems of extraction and distribution. Supplies of non-biotic energy are finite. The problems of supply in the next decades are sufficient of themselves to give pause to those who assume that growth as we have known it in recent decades can continue to float on cheap non-biotic energy.
The second flux of energy I wish to examine is the flux through biotic systems, which is summarized in Table 3. This flux, while often overlooked by those considering the issues of the human future, is far more fundamental to human welfare than the nonbiotic energy we have been considering. With only trivial exceptions this energy represents all of the life of the earth including man and sets one limit on the size of human activities. Hidden in the table is all of human food, both plant and animal, some of man's fuel, his fiber and other resources; hidden also are services such as the stabilization of water flows, the amelioration of climate, the cleansing of water and air, and the control of plant and animal populations. These services are performed at no cost to man by systems that build and repair themselves. The services to man can be disrupted and lost; when they are, large costs accrue to society for flood control, for land stabilization, for subsidies of various types, for pest control, and for various forms of social repair and relief. It is reasonable to assert that when large increments in the earth's capacity for maintaining this flux of biotic energy are lost, the earth has lost a significant segment of its capacity for support of man.
This energy, too, is finite: the total for the world was estimated most recently by Whittaker and Likens (1973) as 841 x 1012 KWH of net primary production per year. Net primary production is the dry organic matter or energy that is left over after the needs of the plants for metabolism have been filled; it is the energy available to support man, other animals and the decay organisms.
More than 60% of the earth's net production is terrestrial, most of that in forests. Cultivated land provides for only 43 x 1014 KWH of this total. Probably somewhere between 5 and 10% of the world total is used directly now in support of man as food, fuel or fiber. The fraction of the net production of the sea used as food may be higher than that for land because we harvest only fish and may be harvesting fish now at close to the maximum rate that the oceans can sustain.
The most difficult question for us is how much of this flux is used indirectly in support of man through maintenance of essential service? How big can human activities get with respect to the rest of life before all aspects of life in the broadest context of the meaning of "life" are progressively degraded? It seems very doubtful that we will be able to substitute energy-based technologies for all of the functions of forests, for the functions of the biota of the oceans, or for the biota of the coastal wetlands. These are simple systems in the limited sense that they run themselves. They do not require man-controlled energy to sustain them; they do their job in support of man without any tinkering from us. How can we measure the total function of these systems in support of man? Keeping in mind the age-old principle of ecology that no single- factor analysis is ever adequate, we may use as one criterion a comparison of the flux of energy through natural systems with that through man-dominated systems to establish an estimate of the equivalence between the constructive forces of ecological succession and the biotically destructive forces of fossil-fueled man. Table 4 offers such a comparison (Woodwell 1972).
Less than 0.1 % of the solar energy impingent on the top of the atmosphere is fixed in photosynthesis and made available as net production. This does not mean that photosynthesis is inefficient, it simply means that the rest of the solar energy is used in other ways. Photosynthesis provides an average worldwide density of net production of 1.4 KWH/m2/year of the surface of the earth. The non-biotic energy flux controlled by man when averaged over all of the land, is very much lower, about 0.3 KWH/m2/year; the average flux in the U.S. is about 1.67 KWH/m2/year, appreciably less than 5-15 KWH/m2 characteristic of forests and agriculture in the temperate zone. In areas such as Manhattan and Brooklyn the flux of non-biotic energy probably rises to 1,000-3.000 KWH/m2/year (Table 4), nearly as high as the mean solar flux at the top of the atmosphere. These areas are clearly dependent on other regions for food, fiber and essential services. The significance of the worldwide fluxes and the U.S. flux require further analysis. What can we say about the effects on the biosphere of the growth of human activities to the point of using an average of 1.67 KWH of energy annually per square meter over the entire U.S.? The answer is sufficiently complex to be easily ignored. I shall offer an answer in two segments. First, a general segment showing the pattern of change in the biota caused by disturbance; second an examination of certain specific effects that are more or less directly caused by energy production.
There is a popular assumption that the earth's biota is a more or less random array of species, capable of adjusting by evolution or short-term successional rearrangements to virtually any disturbance. The assumption is misleading. A hundred years of post-Darwinian experience has shown that there are clear, quantitative relationships between species by whatever criterion we choose for measurement. If we choose energy, we can show that there is in any mature natural community a transfer of 10-20% of the energy fixed by the plants to animals that eat plants.
Consumers of these animals commonly take 10-20% of this energy. And so on through two or three levels of carnivores. No matter how large the plant population and its net production, carnivores will be rare because there is simply not enough energy transferred to them to support them in abundance. This does not mean that they are unimportant; they exert controls over the sizes of populations below them in the trophic structure that keep the flow of energy within the 10-20% limits. This simplification emphasizes that there are quantitative relationships between populations in nature. Natural systems have powerful interactive mechanisms to maintain these relationships and to preserve the integrity of biotic structure. There is overwhelming evidence that man is now overriding these interactive mechanisms by changing the basic chemistry, physics and therefore the biology of the earth, locally, regionally, and worldwide. What are the changes, how important are they, and what should be done?
The changes, no matter how complex they may appear and potentially advantageous in one or more respects, are reductions in biotic structure that can only be considered unstabilizing and retrogressive. The pattern is consistent throughout all of the plant and animal communities of the earth. First, the highly specialized carnivores, perched high in the food web, are reduced or eliminated either by the accumulation of toxins such as the chlorinated hydrocarbons or by changes in the food web below them that leave them without an essential ingredient of their environment. Second, the entire array of plants and animals is changed from one in which large bodied, long-lived species occur to one in which small-bodied, short-lived, rapidly reproducing plant or detritus-eating organisms predominate. We see this pattern now in the reduction of forests in the Los Angeles Basin by toxins in the air. The forest is replaced by low growing shrubs and annual herbs. It can be illustrated dramatically in agriculture where use of broadly toxic compounds as insecticides has eliminated predators and competitors not only of the target species but also of other previously benign inhabitants of the crop, releasing insect and mite populations as new "pests", all of which are herbivorous competitors with man for the crop. It can be seen in carefully designed experiments such as those at Brookhaven National Laboratory where ionizing radiation has been used to reduce the structure of a forest systematically to offer an opportunity to study such questions. It can be seen in the biotic impoverishment of the lands around the Mediterranean and in eutrophic and polluted streams, lakes and estuaries.
Data from Lake Pontchartrain obtained by R. Darnell (1961) illustrate these points for a disturbed estuarine lake. The lake was receiving significant quantities of organic matter at the time of the study and was turbid with Mississippi River silt. It contained a surprising diversity of consumers, most of which showed a dependence on two or more sources of food (Fig. 2). Most, but not all, were dependent on organic detritus in some degree. It is clear that with further disturbance such as elimination of bottom dwelling animals by siltation, by dredging or by an oil spill, the fish populations would shift still more heavily toward plant and detritus-eating forms low in the list insofar as the fish survived at all.
It is important that here few species of fish were dependent directly on the plants; most fed only indirectly through detritus, zooplankton, or other fish. Disruption of one of these populations has implications throughout the system, although the changes an often difficult to measure. The pattern, however, is clear: a reduction of complexity favoring fewer forms that are detritus feeders. We guess that this would mean a reduction in total production of fish; it would certainly mean a reduction in the variety of fish and in the opportunity for harvest of food that would otherwise be totally unavailable to man, who does not eat phytoplankton, most small zooplankton or detritus.
These are gross disturbances: minor disturbances such as small changes in the chemistry of environment must be assumed to bring increments of change in the same direction, although individual increments may be unmeasured and unmeasurable. We are learning now that fish and various other animals communicate by chemical signals at incredibly low concentrations. With the experience of DDT and radioactivity behind us we would be naive to assume that small concentrations of other substances cannot be accumulated, do not have significant effects at low concentrations, and cannot be returned to man in toxic quantities. Indeed, we must assume that they do have biotic effects and manage our affairs to assure that in those systems, such as the oceans, lakes, streams, and terrestrial communities, where biotic integrity is important to us, there is no accumulation of minor chemical insults that can become significant in total. This conclusion bears directly on the recent legislation on air and water pollution as we shall see in a moment.
There are abundant signs that growth in human influences has already progressed to the point where these individually small insults are world wide. Clear world wide effects seem to be limited to an increase in the CO2 content of air, the worldwide distribution of DDT residues and PCB's to the point where virtually every organism contains detectable residues, to fallout radioactivity, to dust in the atmosphere, and to a worldwide reduction in biotic diversity through a combination of direct exploitation and changes in habitat. While each of these has potentially great significance for man, I use them only to emphasize that we are changing the physics, chemistry and biology of the earth worldwide, a clear sign that growth in the aggregate effect of man has already exceeded the point where we can rely longer on the classical assumptions of an Adam Smith-based economics, in which free enterprise organizes itself through the self-interest of the entrepreneur and the economy grows unbridled into a limitless world.
The magnitude and seriousness of the ecological problems associated with the current scale of human activities is shown most lucidly by a consideration of the acidity of rainfall in the Northeastern United States. Normally rain has acidity that is determined by the CO2 in the atmosphere. On the pH scale rain usually has a value of 5.6-6.0, indicating slight acidity. Increasing acidity is indicated by lower numbers, each whole unit representing a 10 fold increase.
During the past decade rainfall in widely separate parts of the Northeastern U.S. and in Scandinavia has been commonly in the range of 3.8-5.0, occasionally as how as 3.0 (Likens, et al. 1972). The high acidity has been correlated with an increase in the amount of sulphate and
nitrate in the rain and is thought to be caused by these acid forming ions. The source of sulphur is probably fossil fuels, including both petroleum and coal. The sulphur is oxidized in combustion and forms sulphuric acid in precipitation. The nitrate is probably fixed by automobiles. The effects of acid rains are many and important. The acidity is great enough to erode limestone and cement; it is also high enough to affect lakes and streams and to cause serious effects on terrestrial ecosystems. In southern Norway it is reported that the pH of streams has been lowered to the point of eliminating salmon runs (Klein, 1971).Likens and his colleagues (1972) report data suggesting that the acidity of Lake Michigan, the Illinois River, possibly the Ohio River, and the Mississippi has increased in the last 50-75 years. But the most important effects, as yet unmeasured in the United States are on the uplands. Acid rains leach nutrients from leaves and other tissues of plants. Weak acid is also commonly used to extract nutrients from soils. A decade or more of highly acid rains must be assumed to have had effects on nutrient cycles in terrestrial systems in the Northeast, including both forests and agriculture. Continued and increasingly acid rain might reasonably he expected to reduce net production of plants regionally making a major step toward the biotic impoverishment of a segment of a continent. A 10-20% reduction in net primary productivity for the region would be difficult to detect in less than several years. Such a reduction may be a reality now; it will be surprising if it is not demonstrated clearly within the next decade. The fact that the effects are diffused does not diminish their importance. A 10% reduction in the net primary production of the vegetation of the New England States would be a loss of solar energy equivalent to the output of 15 1,000 megawatt reactors operating at full capacity.
Solutions to the acid rain problem are elusive. The sources of the sulphur and nitrogen probably extend as far west as Chicago and south to the Gulf States. The possibility of shifting to low sulphur fuels throughout any significant part of this area seems remote in view of the mounting shortage of oil and the shift to coal. An early reduction in the consumption of fossil fuels, however necessary, scarcely appears possible.
The prospect for the Northeast is for continued, perhaps increasingly, acid rains that will levy a tax on all, but an especially heavy tax on those who gain their livelihoods directly from forestry, agriculture, fishing or related industries. It is a most insidious and regressive tax taken from a resource that should not be available for compromise in the endless series of "trade-offs" made in support of the classical forms of growth. This is a part of the uncounted costs of the growth we have experienced to date that has led to a non-biotic energy flux over the U.S. of 1.67 KWH/m2/year. It is one sign that we are overdeveloped – that we not only cannot sustain further growth in the current pattern but must plan now for a substantial revision in the pattern and intensity of our activities.
Solar energy is the only long term source of energy available now for support of man. Within the next decades we can expect worldwide human demands on the flux of solar energy fixed in photosynthesis to increase with a doubling time of 10-20 years, perhaps less. These demands include food, fuel, fiber and environmental services. The demands extend not only to plants, they extend to the full range of diversity of the biota. This diversity offers not only stability and predictability of function, but also a wide range of resources to man.
The challenge for us is to recognize the dependence of man on the earth's biota and to bend our phenomenal technology resources to see that the biota is not only preserved but that its support for man is enhanced in the most energetically efficient ways consistent with long continued use. This is not a stance against growth; it is a challenge to redirect growth into new and exciting topics consistent with the facts of a 20th Century earth headed for 7 billion people in about 30 years. The conclusions seem obvious:
1. The earth's most important resource is its capacity to fix solar energy through photosynthesis and to use it in support of life. This is the earth's largest flux of energy; its management must now become a major and increasing concern of governments.
2. Man probably uses directly 5-10% of the net primary production of plants; the worldwide changes in the quality of air and water and the reductions in the earth's biota indicate that he is using all of the rest of that energy in secondary services and is in effect now mining the life of the earth.
3. Man's use of non-biotic energy has reached about 5% of the magnitude of worldwide net production of plants and secondary effects of its use at that level are having serious toxic effects on the earth's biota, probably reducing overall the fixation of solar energy and its availability in support of man.
4. Growth in the use of fossil fuels and other energy sources will probably be limited in the next decades by the problems of supply and distribution, forcing major changes in the technological societies that will include restraint of growth in energy-rich technologies.
5. The inevitable struggles for more energy that are intensifying rapidly now should not be allowed to destroy additional segments of the earth's capacity for fixing solar energy. National and international policies on energy development and use are needed now with policies on population to avoid increasing conflict and further degradation of biotic energy sources.
6. The assumption that setting standards for toxins on the basis of thresholds for biotic effects will protect the earth's biota and man is false. There is no way of determining thresholds for the myriad of substances that can be developed and released, no way of controlling releases, no sure way of monitoring for the substances, and no basis for belief that thresholds for effects on natural ecosystems exist. The alternative is, as stated in the Water Pollution Control Act of 1972, preservation of the chemical, physical and biotic integrity of those areas of the earth not directly manipulated by man for urban or agricultural uses.
7. The assumption that the environment has an assimilative capacity for all human insults is misleading and inconsistent with the imperative that the earth's biota be preserved for continuous use by man. An assimilative capacity for organic matter or heat does not imply an assimilative capacity for mercury, lead or other substances that may accompany the organic matter. The evidence is overwhelming that man has already exceeded the assimilative capacity of the biosphere for CO2, chlorinated hydrocarbon pesticides, PCB's, dust and possibly fossil fuel energy. Assimilative capacity is a useful concept only within these areas of the earth that
man determines that he will manage intensively.
8. Economic principles are an insufficient basis for management of the biosphere or such large segments of it as the United States controls. The limits of the earth can he accommodated by recognition of the fact that the biosphere is a series of interacting units, oceans, forests, estuaries, cities, agricultural units, each of which has definable characteristics including interactions with other units. Some, such as the oceans, cannot he managed intensively; others such as cities and agricultural regions, must be. The design and management of these units is an essential topic for science and government. It is encouraging that our laws are now beginning to reflect in their objectives some of the realities of the biosphere.
9. The pattern of change necessary in the design of human activities is clear. The further diffusion of toxic influences around the globe must be checked. A certain amount of retrenchment and repair is necessary to assure the stability of biotic resources. Cities cannot be allowed to dispose of wastes in the oceans; fresh water supplies, nutrient elements and mineral resources are to be conserved and recycled; estuaries and coastal waters cannot be used for cooling power plants or usurped for other industrial uses; they are essential to maintenance of the oceanic biota, including especially the fisheries.
10. These changes in perspective and function of government can come only with a major change in objectives, away from the attractive, even beguiling, concept that economic growth will solve all problems and toward a recognition that the earth's basic resources of life and energy are finite. The transition requires major support from science, from the educational establishment, and from legislative bodies. Private enterprise cannot be expected to make these innovations. Government must lead by providing the domestic climate and resources for the massive research and educational needs that such a transition requires. We should at the moment be building at least two national laboratories, one in the East and one in the West to address directly the questions of how to reconcile the needs of 20th Century man with the facts of a living but finite earth. Instead we are watching the dismantling of science. We would be terrified, if we were thoughtful.
11. The inevitable restriction of growth in energy-dense activities does not restrict growth in all segments of society. On the contrary the problems present an intellectual challenge unprecedented in history. We have now a great new freedom to examine in detail the enduring question of what man's most rewarding circumstances might be. On these topics growth has barely begun.