The Faber Book of Science (65 page)

How many people is the earth able to sustain?

The question is incomplete as it stands. One must modify the question by asking further: At what level of technology? And modify it still further by asking: At what level of human dignity?

As for technology, perhaps we can simply ask for the best. We can say that the more advanced technology is, the more people the earth can support, so let us not stint. After all, technology could give us the atomic bomb and put men on the moon and we should set no limits to it.

Let us accept, then, the dream that technology is infinitely capable and proceed from there. How many people can the earth sustain assuming that technology can solve all reasonable problems?

To begin with, it is estimated that there are twenty million million tons of living tissue on the earth, of which 10 percent, or two million million tons, is animal life. As a first approximation, this may be considered a maximum, since plant life cannot increase in mass without an increase in solar radiation or an increase in its own efficiency in handling sunlight. Animal life cannot increase in mass without an increase in the plant mass that serves as its ultimate food.

The mass of humanity has been increasing throughout history; and it is still increasing, but is doing so at the expense of other forms of animal life. Every additional kilogram of humanity has meant, as a matter of absolute necessity, one less kilogram of nonhuman animal life. We might argue, then, that the earth can support, as a maximum, a mass of mankind equal to the present mass of all animal life. At that point, the number of human beings on the earth would be forty million million, or over eleven thousand times the present number. And no other species of animal life would then exist.

What will this mean? The total surface of the earth is five hundred twenty million square kilometers, so that when human population reaches its ultimate number, the average density of population will be eighty thousand per square kilometer – twice the density of New York’s island of Manhattan. Imagine such a density everywhere if the earth’s population is spread out evenly – including over the polar regions, the deserts, and the oceans.

Can we imagine, then, a huge, world-girdling complex of high-rise apartments (over both land and sea) for housing, for offices, for industry? The roof of this complex will be given over entirely to plant growth; either algae, which are completely edible, or higher plants that must be treated appropriately to make all parts edible.

At frequent intervals, there will be conduits down which water and plant products will pour. The plant products will be filtered out, dried, treated, and prepared for food, while the water is returned to the tanks above. Other conduits, leading upward, will bring up the raw minerals needed for plant growth, consisting of (what else) human wastes and chopped-up human corpses. And at this point, of course, no further increase in human numbers is possible; so rigid population planning would then be necessary if it had not been before.

But if this number can be supported in theory, does it represent a kind of life – and this is for each of you to ponder – consonant with human dignity?

Can we buy space and time by transferring human beings to the moon? To Mars?

Consider – How long, under present conditions, will it take us to reach the global high-rise? At present, the earth’s population is
thirty-six
hundred million and it is increasing at a rate that will double the figure in thirty-five years. Let us suppose that this rate of increase can be maintained. In that case, the ultimate population of forty million million will be reached in 465 years. The global high-rise will be in full splendor in
AD
2436.

In, that case, how many men do you think it will be possible to place, and support, on the moon, Mars, and elsewhere in the next 465 years? Be reasonable. Subtract your figure from forty million million and ask yourself if the contribution the other worlds can make is significant.

Can we buy further time by going beyond the sun? Can we make use of hydrogen fusion power to irradiate plant life? Or can we make food
in the laboratory, with artificial systems and synthetic catalysts, and declare ourselves independent of the plant world altogether?

But that requires energy and here we come to another point. The sun pours down on the earth’s day-side, some fifteen thousand times as much energy per day as mankind now uses. The earth’s night-side must radiate exactly that much heat back into space if the earth’s average temperature is to be maintained. If mankind adds to the heat on earth by burning coal, that additional energy must also be radiated out to space; and to accomplish this the earth’s average temperature must rise slightly.

At present, man’s addition to solar energy produces a terrestrial temperature-rise that is utterly insignificant; that addition, however, is doubling every twenty years. At this rate, in a hundred sixty-five years (by 2136) mankind’s contribution to the heat that the earth must radiate away will amount to one percent of the sun’s supply, and this will begin to produce unacceptable changes in the earth’s temperature.

So, far from helping ourselves with further energy expenditures in the global high-rise world of ad 2436, we must accept a limitation of energy expenditure a full three centuries earlier, when man’s population is less than a five-hundredth of its ultimate. We might improve matters by increasing the efficiency with which energy is used; but the efficiency cannot rise above a hundred percent, and that does
not
represent an enormous increase over present levels.

But,
and this is a large ‘but,’ can we really depend on technology to make the necessary advances to bring us to energy-limits safely in a century and a half? By then the population, at the present level of increase, will be twenty times what it is today; and to bring man’s level of nourishment to a desirable point, we would need a fortyfold increase in the food supply. We would also have to ask technology not only to arrange the necessary hundred-fifty-fold increase in energy utilization in a century and a half but to arrange to take care of what will be, very likely, a hundred-fifty-fold increase in environmental pollution and in waste production of all kinds.

How do things look at present?

Far from making strides to keep up with the population increase, technology is falling visibly behind. How can the global high-rise be a reasonable future vision when present-day housing is steadily deteriorating even in the most advanced nations? How can we reach our limit of energy expenditure when New York City finds itself, each
year with a growing deficit of power supply? Only yesterday, the third landing of men on the moon caused television viewing to go up, and a cutback in electrical voltage was immediately made necessary.

The earth’s population will be at least six thousand million in the year 2000. Will the planet’s technology be able to support that population even at present-day, wholly unsatisfactory levels? Will human dignity be compatible with such a population (let alone with forty million million), when in our cities
today
human dignity is disappearing; when it is impossible to walk safely by night (and often by day) in the largest city of the world’s most technologically advanced nation.

Let us not look into the future at all, then. Let us gaze firmly at the present. The United States is the richest nation on earth and every other nation would like to be at least as rich. But the United States can live as it does only because it consumes slightly more than half of all the energy produced on earth for human consumption – although it has only a sixteenth of the earth’s population.

What, then, if some wizard were to wave his magic wand and produce an earth on which every part of the population everywhere were able to live at the scale and the standard of Americans? In that case, the rate of energy expenditure would increase instantly to eight times the present world level and, inevitably, the production of waste and pollution would increase similarly – this with no increase in population at all.

And can present-day technology supply an eightfold increase in energy utilization (and that of other resources as well) and handle an eightfold increase in waste and pollution, when it is falling desperately short of supplying and handling present levels? Do you ask for time in which technology can arrange for such an eightfold increase? Very well, but in that time, population will increase, too, very likely more than eightfold.

In short, then, to the revised question, How many people is the earth able to sustain at a desirable level of technology and dignity? there can be only a short and horrifying answer –

Fewer than now exist!

The earth cannot support its present population at the average level of the American standard of living. Perhaps, at the moment, it can only support five hundred million people at that standard. Nor can technology improve itself to better this mark, with the present
population clamoring for what it cannot have and with that population growing at a terrible rate.

What, then, will happen?

If matters continue as they are now going, there will be a continuing decline in the well-being of the individual human being on earth. Calories per mouth will decrease; available living quarters will dwindle; attainable comfort will diminish. What is more, in the increasing desperation to reverse this, man may well make wild attempts to race the technology engine at all costs and will then further pollute the environment and decrease its ability to support mankind. With all this taking place, there will be a struggle of man against man, with each striving to grasp an adequate share of a shrinking
life-potential
. And there cannot help but be an intensification of the human-jungle characteristics of our centers of population.

In not too long a time, the population increase will halt; but for the worst possible reason – there will be a catastrophic rise in the death rate. The famines will come, the pestilence will strike, civil disorder will intensify, and by
AD
2000 some governmental leader may well be desperate enough to push the nuclear button.

How to prevent this, then?

We must stop living by the code of the past. We have, over man’s history, developed a way of life that fits an empty planet and a short existence marked by high infant-mortality and brief life-expectancy. In such a world there was a virtue in having many children, in striving for growth in numbers and power, in expansion into endless space, in total commitment to that limited portion of mankind that could make up part of a viable society.

But none of this is so any longer. At the moment, child mortality is low, life expectancy high, the earth full. There are no empty spaces of worth, and so interdependent is man that it is no longer safe to confine loyalty to only a portion of mankind.

What was common sense in a world that once existed has become myth in the totally different world that now exists, and suicidal myth at that.

In our overpopulated world we can no longer behave as though woman’s only function in life is to be a baby-producing machine. We can no longer believe that the greatest blessing a man can have is many children.

Motherhood is a privilege we must literally ration, for children, if
produced indiscriminately, will be the death of the human race, and any woman who deliberately has more than two children is committing a crime against humanity.

We also have to alter our attitude toward sex. Through all the history of man it has been necessary to have as many children as possible, and sex has been made the handmaiden of that fact. Men and women have been taught that the only function of sex is to have children; that otherwise it is a bestial and wicked act. Men and women have been taught that only those forms of sex that make conception possible are tolerable, that everything else is perverse, unnatural, and criminal.

Yet we can no longer indulge in such views. Since sex cannot be suppressed, it must be divorced from conception. Birth control must become the norm and sex must become a social and interpersonal act rather than a child-centered act.

We also have to alter our attitude toward growth. The feeling of ‘bigger and better’ that bore up mankind through his millennia on this planet must be abandoned. We have reached the stage where bigger is no longer better. Although the notion of more people, more crops, more products, more machines, more gadgets – more, more, more – has worked, after a fashion, up to this generation, it will no longer work. If we attempt to force it to work, it will kill us rather quickly.

In our new and finite world, where for the first time in history we have reached, or are reaching, our limit, we must accept the fact of limit. We must limit our population, limit the strain we put on the earth’s resources, limit the wastes we produce, limit the energy we use. We must preserve. We must preserve the environment, preserve the other forms of life that contribute to the fabric and viability of the biosphere, preserve beauty and comfort. And if we do limit and preserve, we will have room for deeper growth even so – growth in knowledge, in wisdom, and in love for one another.

We also have to alter our attitude toward localism. We can no longer expect to profit by another’s misfortune. We can no longer settle quarrels by wholesale murder. The price has escalated to an unacceptable level. World War II was the last war that could be fought on this planet by major powers using maximum force. Since 1945, only limited wars have been conceivable, and even these have been monumental stupidities, as the situations in Southeast Asia and in the Middle East make clear.

The world is too small for the kind of localism that leads to wars. We can have special pride in our country, our language, and our literature, our customs and culture and tradition, but it has to be the abstract pride we have in our baseball team or our college – a pride that cannot and must not be backed by force of arms.