Science in Christian Perspective


Environmental Control*
Department of Zoology University of California, Davis, California

From: JASA 21 (June 1969): 39-41.

Our species has faced several critical problems in its evolution: pandemics, exhaustion of readily available sources of food, fuel and other materials, inefficient and slow transportation and communication systems, and so on. When these problems were acute, the probability of a human being surviving to old age was low; consequently, population death rates were in balance with population birth rates, and the world population of human beings grew very slowly. Sometimes, as in Europe in the 14th century, over large areas and for extended periods, life was so rigorous that populations actually declined. Until the last two centuries, man faced such serious problems on this planet that he was a relatively unimportant factor in the overall scheme of life. However, now that the important problems of the past have been solved, a new group of problems has arisen, perhaps potentially more deadly to the continued life of our species on this planet.

The Central Challenge

The central problem is that with a relaxation in man's struggle for simple survival, there has been a drop in death rates all over the world, unaccompanied by corresponding drops in birth rates. The result is the well-known population explosion. What is not nearly so well known is the precise dimension of the problem. Even experts on population problems are guilty of statements to the effect that the human population is "growing exponentially," or "doubling every 30 years." Both these statements imply the same thing: that the human population is growing at any instant at a rate proportional to the world population size at that instant. In fact, this is not the case: we are growing at a much faster rate. In 1960 three engineers predicted that humanity would squeeze itself to death in 2026; nobody paid much attention. Even fewer seem to have noticed that subsequent data from the United Nations have shown their predicted growth rates to he badly underestimating current growth rates. What can scientists and concerned laymen do? First, support birth control programs, particularly in newly developing countries. Second, speak out firmly against the notion that a man is not a real man unless he has several children. Experts on the population problem insist that physical birth control devices are not the basic problem. The basic problem exists in the minds of the people who are not disposed to use contraceptive measures even if they are available free until they have had three or four children.

Many other problems are a consequence of human population explosion and the massive resultant effect our species is having on everything which occurs on this planet. Five problem areas in particular merit much more exposition, and are dealt with briefly here

Can the Sea Solve the Food Problem?

One particularly dangerous notion ingrained in our popular culture is that the sea is an inexhaustible source of food, and indeed everything else. The facts speak differently. First, much of the world's oceans are aquatic deserts, relatively poor in minerals and therefore supporting little plant or animal life. Second, much of what we remove from the ocean is high up on the food chain: we eat fish predators that eat small fish that eat crustaceans that eat plankton that derive their energy from the sun. At each step in this chain, there is tremendous loss of energy. The efficiency of the whole process is extremely low, comparable to that of growing grass to feed to rabbits which are eaten by lynx which are then eaten by mountain lions, which are then eaten by man. Man in fact does nothng comparable to this on land, either eating plants directly, or herbivores which eat the plants. In Asia, particularly, even the herbivore step is too costly, and most people live on an almost entirely plant diet.
Some people will counter this argument by insisting that man will some day live on the algae in the ocean. The central difficulty here is that many algae exist in the water at such low densities that much pumping and sieving would be required to extract useful quantities. If the number of calories required to extract 100 calories worth of algae from the ocean is too high, then the cost of the process in energy is exorbitant, without regard to the cost in money. The only parts of the oceans rich enough in minerals to support dense plant and animal concentrations of economic consequence are close to the continents; it is precisely these parts of the oceans we are polluting and degrading most rapidly.

Can We Survive Pollution?

Many forms of pollution are by now sufficiently well known to require no further mention. Pesticides are in this category. Anyone who has lived on the shores of Lake Erie for at least 30 years will require no further discussion of what this species is doing to his environment. New Yorkers for whom the Hudson River is a resource of limited usefulness presumably also fall into this category. However, man is polluting this planet in more important and more subtle ways which are in dire need of open discussion. Two important recent incidents have alerted the population to hazards of petroleum products being released at sea. The incidents aroused wide interest, because the fractions released were in enormous quantities and were swept to, or close to shore. However, ocean-going vessels routinely clean themselves at sea by flushing out a viscous fraction of crude petroleum left behind after the lighter fractions have been refined off. This heavy fraction is called bunker fuel, and in the cold north Atlantic in winter has a very destructive effect on sea birds that become trapped in It (viscosity increases with decreasing temperature). Millions of birds are thus killed every year. The significance of this is that the sea birds' feces (guano) rich in essential minerals aid in circulation of chemical elements in the ocean which are the basic input to the cycle which terminates in commercial fish stocks.

Pollution of the air is probably the most serious pollution problem and will probably have the widest array of types of (often surprising) effects. There is considerable evidence that air pollution has implications for the weather, for human health, for growth of agriculture plants and animals, and indeed for almost any imaginable chemical process on this planet. It is not widely recognized that the total quantity of air which determines the entire course of events on this planet is not very great: most of it occurs in a sphere seven miles out from the earth's surface. Man is now in a position to have a very major effect on this volume of gas. A regular jet traveller will have noticed, for example, that jet contrails are a major contributor to the origination of clouds at certain altitudes and in parts of North America. Very interesting time lapse motion pictures which have been taken of the Los Angeles Basin throughout a typical day by strategically placed cameras distributed around the basin show dramatically what a major effect man is having on the air that supports him and his civilization, and all life on earth.

What can scientists and concerned laymen do? First, support birth control programs, particularly in newly developing countries. Second, speak out firmly against the notion that a man is not a real man unless he has several children.

Those of us fortunate enough to live in thinly populated parts of this country find it a trying ordeal to visit the large manufacturing cities of the northeast and the midwest, because of the oppressively poisonous smelling air. Unfortunately, an increasing proportion of the U.S. population is becoming adapted to living in this air, and tolerating sinus operations, rapidly rising emphysema death rates, lung cancer, and all the concomitant hazards. Unfortunately, Homo sapiens is a remarkably adaptable species, so much so that we may have adapted to our ultimate doom before we are aware that it is upon us. The time has come to cease adapting, and speak out vigorously about the contamination of the environment before it becomes uninhabitable.

Ironically, much of the material with which we are destroying the planet could be very useful as input for various factory processes. This is true of smoke, wood chips, beer cans, abandoned ears, newspapers, and most solid-liquid waste. Massive, aggressive research programs on techniques for reclaiming solid and liquid waste should be initiated before exhaustion of our mineral wealth, forests, and fossil fuels forces us to such massive efforts on a crash basis. It has turned out that corporations devoted to such reclamation can be remarkably profitable.

Is Disease Really Being Conquered?

Man's thinking with respect to disease has gone through tremendous changes. Examination of the diaries of people who lived a few centuries ago shows that epidemics and pandemics were rarely far from their minds, Peter Kaim, the Swedish naturalist, in 1748 was impressed by the prevalence of malaria in the United States. With the single exception of influenza, no disease has had an important effect on the history of western civilization in this century. Previously, epidemics wiped out up to 25 percent of the population of an entire continent, and were probably a major determinant of the outcome of all battles and wars, (Up to this century, a majority of the deaths in wars were due to disease, not wounds; since the incidence of disease could he very different in two opposing armies, depending on the sophistication of sanitation measures, the winning side was often that with the most healthy-soldiers ready to do battle. This matter has been analyzed largely by historically-oriented epidemiologists, rather titan epidemiologically-oriented historians, who are a rare breed.)
However, disease may soon return to its original place as one of the central objects of man's attention. An important but little known theorem of mathematical epidemiology holds that for every disease there is some threshold level of population at which the disease breaks out spontaneously, which is inversely proportional to the infectivity rate. That is, for any given disease, as sanitation practices which minimize probability of infection improve, the threshold population density for the disease rises. However, there is a lower limit below which the infectivity rate cannot he dropped further. Thus, there is an upper limit beyond which the threshold population cannot be raised. If these notions are correct, 'then as human populations become more and more dense, we will reach the threshold densities for more and more potentially pandemic diseases. Thus, the old enemies of mankind such as plague and typhus may be back again, with some important new enemies along with them, such as dengue fever. A careful observer of news from Vietnam and other parts of southeast Asia may be given pause for thought by these ideas. The point is that ever-increasing human populations are a mixed blessing, and before long, the blessing may he outweighed by the other part of the mixture.

Can Novel Forms of Agriculture Be Used?

Every time European settlers moved elsewhere, they had available alternative courses of action, although it is only in the last six years that it has been widely recognized that the alternative existed. One possibility was to transplant European style agriculture, built around conventional grains, and standard breeds of cattle, sheep, pigs and gnats. This was the option invariably chosen. The other alternative was to set up intensive and scientific harvesting of native plants and animals, such as bison, kangaroos, antelopes, etc. Native organisms have often been totally or almost wiped out, then replaced by imported species. Now if it is true that natural selection selects a given place for those species and strains which, because they are best adapted there, make most efficient use of incident solar radiation, then man has been guilty of a very foolish mistake. Organisms which make best use of resources in a particular habitat have been replaced by other types which are not so efficient, as when buffalo (bison) were replaced by Shorthorns and Herefords in the American West. Data bearing on this point have become more plentiful recently. It turns out that in Africa, for example, higher quantities of meat can be produced per annum off a given acreage by harvesting 13 species of native game than by harvesting conventional livestock. Perhaps even more important, much of the native game produces higher quality meat. Critics of this argument will assert that buffalo meat, for example, is inedible. This would have come as interesting news to many of the early American settlers also somehow consumed about 1,300 pounds of the stuff per person per annum, every year of their lives.

The moral of this story is: don't change anything until it has been conclusively demonstrated that the change is for the better. Mother Nature has produced her results after a rather long sequence of experiments, and it may take considerably more sophistication than we sometimes realize to improve on her work.

Are There Significant Hazards in Pest Controls?

As human populations become ever larger, it becomes more important that agriculture be as efficient as possible. Pest control needs very critical reexamination, for this reason. The public should look carefully at any pest control campaign and ask the following question: in the season following the season in which we made an intensive effort to control a particular pest, were there as many pests as the previous season, or more, or less? If the number of pests in the season following treatment was equal to or greater than the number preceding treatment, then something is wrong. One does not have to be very observant to realize that this is often the case. Further, criteria for successful pest control campaigns are repeatedly being established by those campaigns which are successful; e.g. the Florida screwworm program, which eradicated the screwworm. A program which purports to be successful must gradually reduce densities of the pest, or the public is being deceived. The fact is, there are a very large number of types of pest control strategy now available, and if a pest control campaign does not gradually reduce pest densities from one year to another, it simply means that the program manager chose the wrong method; the people who pay them should then feel free to point this out.

* Kenneth E. Watt is a member of the Ecological Study committee to the Special Commission for Weather Modification of the National Science Foundation. He is the author of Ecology and Resources Management: A Quantitative Approach published by McGraw-Hill in 1968. This article is reprinted by permission from Science and Technology Review, Spring-Summer 1968 issue, published by the McGraw-Hill Book Company.