by Isaac Asimov
A particularly interesting, and unexpected, echo of early human migrations in Europe showed up in Spain. It came out in a study of Rh blood distribution. (The Rh blood groups are so named from the reaction of the blood to antisera developed against the red cells of a rhesus monkey. There are at least eight alleles of the responsible gene; seven are called Rh positive, and the eighth, recessive to all the others, is called Rh negative because it shows its effect only when a person has received the allele from both parents.) In the United States, about 85 percent of the population is Rh positive; 15 percent, Rh negative. The same proportion holds in most of the European peoples. But, curiously, the Basques of northern Spain stand apart, with something like 60 percent Rh negative to 40 percent Rh positive. And the Basques are also notable in having a language unrelated to any other European language.
The conclusion that can be drawn is that the Basques are a remnant of a prehistoric invasion of Europe by an Rh-negative people. Presumably a later wave of invasions by Rh-positive tribes penned them up in their mountainous refuge in the western corner of the continent, where they remain the only sizable group of survivors of the early Europeans. The small residue of Rh-negative genes in the rest of Europe and in the American descendants of the European colonizers may represent a legacy from those early Europeans.
The peoples of Asia, the African blacks, the American Indians, and the Australian aborigines are almost entirely Rh positive.
Humanity’s Future
Attempting to foretell the future of the human race is a risky proposition that had better be left to mystics and science-fiction writers (though, to be sure, I am a science-fiction writer myself, among other things). But of one thing we can be fairly sure. Provided there are no worldwide catastrophes—such as a full scale nuclear war, or a massive attack from outer space, or a pandemic of a deadly new disease—the human population will increase rapidly. It is now five times as large as it was only two centuries ago. Some estimates are that the total number of human beings who have lived over a period of 600,000 years comes to 77,000,000,000. If so, then nearly 6 percent of all the human beings who have ever lived are living at this moment. And the world population is still growing at a tremendous rate.
Since we have no censuses of ancient populations, we must estimate them roughly on the basis of what we know about the conditions of human life. Ecologists have estimated that the pre-agricultural food supply—obtainable by hunting, fishing, collecting wild fruit and nuts, and so on=—could not have supported a world population of more than 20,000,000, and, in all likelihood, the actual population during the Paleolithic era was only one-third or one-half of this figure at most. Hence, as late as 6000 B.C., it could not have numbered more than 6 to 10 million people—less than the population of a single present-day city such as Shanghai or Mexico City. (When America was discovered, the food-gathering Indians occupying what is now the United States probably numbered not much more than 250,000—or as if the population of Dayton, Ohio, were spread out across the continent.)
THE POPULATION EXPLOSION
The first big jump in world population came with the Neolithic Revolution and agriculture. The British biologist Julian Sorrell Huxley (grandson of the Huxley who was “Darwin’s bulldog”) estimates that the population began to increase at a rate that doubled its numbers every 1,700 years or so. By the opening of the Bronze Age, the world population may have been about 25 million; by the beginning of the Iron Age, 70 million; by the start of the Christian era, 170 million, with one-third crowded into the Roman empire, another third into the Chinese empire, and the rest scattered. By 1600, the earth’s population totaled perhaps 500 million, considerably less than the present population of India alone.
At that point, the smooth rate of growth ended, and the population began to explode. World explorers opened up some 18 million square miles of almost empty land on new continents to colonization by the Europeans. The eighteenth-century Industrial Revolution accelerated the production of food and of people. Even backward China and India shared in the population explosion. The doubling of the world’s population now took place not in a period of nearly two millennia but in less than two centuries. The population expanded from 500,000,000 in 1600 to 900,000,000 in 1800. Since then it has grown at an ever faster rate. By 1900, it had reached 1,600,000,000. In the first seventy years of the twentieth century, it has climbed to 3,600,000,000, despite two world wars.
In 1970 the world population was increasing at the rate of 220,000 each day, or 70,000,000 each year. This was an increase at the rate of 2.0 percent each year (as compared with an estimated increase of only 0.3 percent per year in 1650). At this rate, the population of the earth would double in about thirtyfive years; and in some regions, such as Latin America, the doubling would take place in a shorter time.
At the moment, students of the population explosion are leaning strongly toward the Malthusian view, which has been unpopular ever since it was advanced in 1798. As I said earlier, Thomas Robert Malthus maintained, in An Essay on the Principle of Population, that population always tends to grow faster than the food supply, with the inevitable result of periodic famines and wars. Despite his predictions, the world population has grown apace without any serious setbacks in the past century and a half. But, for this postponement of catastrophe, we can be grateful, in large measure, that large areas of the earth were still open for the expansion of food production. Now we are running out of tillable new lands. A majority of the world’s population is underfed, and we must make mighty efforts to wipe out this chronic undernourishment. To be sure, the sea can be more rationally exploited, and its food yield multiplied. The use of chemical fertilizers must yet be introduced to wide areas. Proper use of pesticides will reduce the loss of food to insect depredation in areas where such loss has not yet been countered. There are also ways of encouraging growth directly. Plant hormones such as gibberellin (studied by Japanese biochemists before the Second World War and coming to Western attention in the 1950s) could accelerate plant growth, while small quantities of antibiotics added to animal feed will accelerate animal growth (perhaps by suppressing intestinal bacteria that otherwise compete for the food supply passing through the intestines, and by suppressing mild but debilitating infections). Nevertheless, with new mouths to feed multiplying at their current rate, it will take Herculean efforts merely to keep the world’s population up to the present none-too-good mark in which some 300 million children under five, the world over, are undernourished to the point of suffering permanent brain damage.
Even so common (and, till recently, disregarded) a resource as fresh water is beginning to feel the pinch. Fresh water is now being used at the rate of nearly 2 trillion gallons a day the world over; although total rainfall, which at the moment is the main source of fresh water, is 50 times this quantity, only a fraction of the rainfall is easily recoverable. And in the United States, where fresh water is used at a total rate of 350 billion gallons a day at a larger per-capita rate than in the world generally, some 10 percent of the total rainfall is being consumed one way or another.
The result is that the world’s lakes and rivers are being quarreled over more intensely than ever. (The quarrels of Syria and Israel over the Jordan, and of Arizona and California over the Colorado River, are cases in point.) Wells are being dug ever deeper; and in many parts of the world, the ground-water level is sinking dangerously. Attempts to conserve fresh water have included the use of cetyl alcohol as a cover for lakes and reservoirs in such regions as Australia, Israel, and East Africa. Cetyl alcohol spreads out into a film one molecule thick, cutting down on water evaporation without polluting the water. (Of course, increasing water pollution by sewage and by industrial wastes is an added strain on the diminishing fresh-water surplus.)
Eventually, it seems, it will be necessary to obtain fresh water from the oceans, which, for the foreseeable future, offer an unlimited supply. The most promising methods of desalting sea water include distillation and freezing.
In addition, experiments are proceeding with membranes that will selectively permit water molecules to pass, but not the various ions. Such is the importance of this problem that the Soviet Union and the United States are discussing a joint attack on it, at a time when cooperation between these two competing nations is, in other respects, exceedingly difficult to arrange.
But let us be as optimistic as we can and admit no reasonable limits to human ingenuity. Let us suppose that, by miracles of technology, we raise the productivity of the earth tenfold; suppose that we mine the’ metals of the ocean, bring up gushers of oil in the Sahara, find coal in Antarctica, harness the energy of sunlight, develop fusion power. Then what? If the rate of increase of the human population continues unchecked at its present rate, all our science and technical invention will still leave us struggling uphill like Sisyphus.
If you are not certain whether to accept this pessimistic appraisal, let us consider the powers of a geometric progression. It has been estimated that the total quantity of living matter on earth is now equal to 2 × 1019 grams. If so, the total mass of humanity in 1970 was about 1/100,000 of the mass of all life.
If the earth’s population continues to double every thirty-five years (as it was then doing), by 2570 A.D. it will have increased 100,000-fold. It may prove extremely difficult to increase as a whole the mass of life the earth can support (though one species can always multiply at the expense of others). In that case, by 2570 A.D. the mass of humanity would comprise all of life, and we would be reduced to cannibalism if some people were to continue to survive.
Even if we could imagine artificial production of foodstuffs out of the inorganic world via yeast culture, hydroponics (the growth of plants in solutions of chemicals), and so on, no conceivable advance could match the inexorable number increase involved in this doubling-every-thirty-five years. At that rate, by 2600 A.D., it would reach 630,000 billion! Our planet would have standing room only, for there would be only 2½ square feet per person on the entire land surface, including Greenland and Antarctica. In fact, if the human species could be imagined as continuing to multiply further at the same rate, by 3550 A.D. the total mass of human tissue would be equal to the mass of the earth.
If there are people who see a way out in emigration to other planets, they may find food for thought in the fact that, assuming there were 1,000 billion other inhabitable planets in the universe and people could be transported to any of them at will, at the present rate of increase of human numbers every one of those planets would be crowded literally to standing room only by 5000 A.D. By 7000 A.D., the mass of humanity would be equal to the mass of the known universe!
Obviously, the human race cannot increase at the present rate for very long, regardless of what is done with respect to the supply of food, water, minerals, and energy. I do not say “will not” or “dare not” or “should not”; I say quite flatly “cannot.”
Indeed, it is not mere numbers that will limit our growth if it continues at a high rate. It is not only that there are more men, women, and children each minute, but that each individual uses (on the average) more of Earth’s unrenewable resources, expends more energy, and produces more waste and pollution each minute. Where population doubles every thirty-five years, energy utilization, in 1970, was increasing at such a rate, that, in thirty-five years, it would have increased not twice but sevenfold.
The blind urge to waste and poison faster and faster each year is driving us to destruction even more rapidly, then, than mere multiplication alone. For instance, smoke from burning coal and oil is freely dumped into the air by home and factory, as is the gaseous chemical refuse from industrial plants. Automobiles by the hundreds of millions discharge fumes of gasoline and of its breakdown and oxidation products, to say nothing of carbon-monoxide and lead compounds. Oxides of sulfur and nitrogen (produced either directly or through later oxidation by ultraviolet light from the sun), together with other substances, can corrode metals, weather construction materials, embrittle rubber, damage crops, cause and exacerbate respiratory diseases, and even serve as one of the causes of lung cancer.
When atmospheric conditions are such that the air over a city remains stagnant for a period of time, the pollutants collect, seriously contaminating the air and encouraging the formation of a smoky fog (smog) that was first publicized in Los Angeles but had long existed in many cities and now exists in more. At its worst, it can take thousands of lives among those who, out of age or illness, cannot tolerate the added stress placed on their lungs. Such disasters took place in Donora, Pennsylvania, in 1948 and in London in 1952.
The fresh waters of the earth are polluted by chemical wastes, and occasionally one of them will come to dramatic notice. Thus, in 1970, it was found that mercury compounds heedlessly dumped into the world’s waters were finding their way into sea organisms in sometimes dangerous quantities. At this rate, far from finding the ocean a richer source of food, we may make a good beginning at poisoning it altogether.
Indiscriminate use of long-lingering pesticides results in their incorporation first into plants, then into animals. Because of the poisoning, some birds find it increasingly difficult to form normal eggshells, so that, in attacking insects, we are bringing perilously close to extinction the peregrine falcon. Almost every new so-called technological advance, hastened into without due caution by the eagerness to overreach one’s competitors and multiply one’s profits, can bring about difficulties. Since the Second World War, synthetic detergents have replaced soaps. Important ingredients of those detergents are various phosphates, which washed into the water supply and greatly accelerated the growth of microorganisms that, however, used up the oxygen supply of the waters—thus leading to the death of other sea organisms. These deleterious changes in water habitats (eutrophication) are rapidly aging the Great Lakes, for instance—the shallow Lake Erie in particular—and are shortening their natural lives by millions of years. Thus, Lake Erie may become Swamp Erie, while the swampy Everglades may dry up altogether.
Living species are utterly interdependent. There are obvious cases like the interconnection of plants and bees, where the plants are pollinated by the bees and the bees are fed by the plants, and a million other cases less obvious. Every time life is made easier or more difficult for one particular species, dozens of other species are affected—sometimes in hard-to-predict ways. The study of this interconnectability of life, ecology, is only now attracting attention, for in many cases human beings, in an effort to achieve some short-term benefit for themselves have so altered the ecological structure as to bring about some long-term difficulty. Clearly we must learn to look far more carefully before we leap.
Even so apparently other-worldly an affair as rocketry must be carefully considered. A single large rocket may inject over 100 tons of exhaust gases into the atmosphere at levels above 60 miles. Such quantities of material could appreciably change the properties of the thin upper atmosphere and lead to hard-to-predict climatic changes. In the 1970s supersonic transport planes (SSTs) traveling through the stratosphere at higher-than-sound velocities were introduced. Those who object to their use cite not only the noise factor involved in sonic booms but also the chance of climate-affecting pollution.
Another factor that makes the increase in numbers even worse is the uneven distribution of human beings over the face of the earth. Everywhere there is a trend toward accumulation within metropolitan areas. In the United States, even while the population goes up and up, certain farming states not only do not share in the explosion but are actually decreasing in population. It is estimated that the urban population of the earth is doubling not every thirty-five years but every eleven years. By 2005 A.D., when the earth’s total population will have doubled, the metropolitan population will, at this rate, have increased over ninefold.
This is serious. We are already witnessing a breakdown in the social structure—a breakdown that is most strongly concentrated in just those advanced nations where urbanization is most apparent. Within t
hose nations, it is most concentrated in the cities, especially in their most crowded portions. There is no question but that when living beings are crowded beyond a certain point, many forms of pathological behavior become manifest. This has been found to be true in laboratory experiments on rats, and the newspaper and our own experience should convince us that this is also true for human beings.
It would seem obvious, then, that if present trends continue. unchanged, the world’s social and technological structure will have broken down well within the next half-century, with incalculable consequences. Human beings, in sheer madness, may even resort to the ultimate catastrophe of thermonuclear warfare.
But will present trends continue?
Clearly, changing them will require a massive effort and will mean that we must change long-cherished beliefs. For most of human history, people have lived in a world in which life was brief and many children died while still infants. If the tribal population were not to die out, women had to bear as many babies as they could. For this reason, motherhood was deified, and every trend that might lower the birthrate was stamped out. The status of women was lowered so that they might be nothing but baby-making and baby-rearing machines. Sexual mores were so controlled that only those actions were approved of that led to conception; everything else was considered perverted and sinful.
But now we live in a crowded world. If we are to avoid catastrophe, motherhood must become a privilege sparingly doled out. Our views on sex and on its connection with childbirth must be changed.
Again, the problems of the world—the really serious problems—are global in nature. The dangers posed by overpopulation, overpollution, the disappearance of resources, the risk of nuclear war, affect every nation, and there can be no real solutions unless all nations cooperate. What this means is that a nation can no longer go its own way, heedless of the others; nations can no longer act on the assumption that there is such a thing as a “national security” whereby something good can happen to them if something bad happens to someone else. In short, an effective world government is necessary—one that is federalized to allow the free play of cultural differences and one that (we hope) can guarantee human rights.