Physics of the Future: How Science Will Shape Human Destiny and Our Daily Lives by the Year 2100

population and resources. Since the food supply expands only linearly with time, while the population grows exponentially, it seemed inevitable that at some point the world would hit the breaking point. Malthus predicted mass famines by the mid-1800s.
    But in the 1800s, the world population was only in the early stages of major expansion, and because of the discovery of new land, the founding of colonies, increases in the food supply, etc., the disasters Malthus predicted never took place.
    In the 1960s, another Malthusian prediction was made, stating that a population bomb would soon hit the earth, with global collapse by the year 2000. The prediction was wrong. The green revolution successfully expanded the food supply. The data show that the increase in food supply exceeded the growth in the world population, thereby temporarily defeating the logic of Malthus. From 1950 to 1984, grain production increased by more than 250 percent, mainly due to new fertilizers and new farming technologies.
    Once again, we were able to dodge the bullet. But now the population expansion is in full swing, and some say we are reaching the limit of the earth’s ability to create food supplies.
    Ominously, food production is beginning to flatten out, both in world grain production and in food harvested from the oceans. The UK government’s chief scientist warned of a perfect storm of exploding population and falling food and energy supplies by 2030. The world will have to produce 70 percent more food by 2050 to feed an extra 2.3 billion people, the UN’s Food and Agriculture Organization has said, or else face disaster.
    These projections may underestimate the true scope of the problem. With hundreds of millions of people from China and India entering the middle class, they will want to enjoy the same luxuries that they have seen in Hollywood movies—such as two cars, spacious suburban homes, hamburgers and French fries, etc.—and may strain the world’s resources. In fact, Lester Brown, one of the world’s leading environmentalists and founder of the World Watch Institute in Washington, D.C., confided to me that the world may not be able to handle the strain of providing a middle-class lifestyle to so many hundreds of millions of people.
    SOME HOPE FOR WORLD POPULATION
    There are some glimmers of hope, however. Birth control, once a taboo topic, has taken hold in the developed world and is making inroads in the developing world.
    In Europe and Japan, we see the implosion, not the explosion, of the population. The birthrate is as low as 1.2 to 1.4 children per family in some European nations, far below the replacement level of 2.1. Japan is being hit with a triple whammy. One, it has the fastest-aging population on earth. Japanese women, for example, have held the record for more than twenty years for having the longest life expectancy of any group. Two, Japan has a plunging birthrate. And three, the government keeps immigration extremely low. These three demographic forces are creating a train wreck in slow motion. And Europe is not far behind.
    One lesson here is that the world’s greatest contraceptive is prosperity. In the past, peasants without retirement plans or social security tried to have as many children as possible to toil in the fields and care for them when they got old, doing a simple calculation: each new child in the family means more hands to work, more income, and more people to nurse you in old age. But when a peasant enters the middle class, complete with retirement benefits and a comfortable lifestyle, the equation flips the other way: each child reduces income and quality of life.
    In the third world, you have the opposite problem—a rapidly expanding population, where much of the population is below the age of twenty. Even where the population explosion is expected to be the largest, in Asia and sub-Saharan Africa, the birthrate has been falling, for several reasons.
    First, you have the rapid urbanization of the peasant population, asfarmers leave their ancestral lands to try their luck in the megacities. In 1800, only 3 percent of the population lived in cities. By the end of the twentieth century, that figure rose to 47 percent, and it is expected to soar above that in the coming decades. The expense of child rearing in the city drastically reduces the number of children in a family. With rents, food, and expenses being so high, workers in the slums of the megacities perform the same calculus and