Science in Christian Perspective
Environmental Control*
KENNETH E. WATT
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.