Population

There is a considerable history of concern over population and health. Philosophers in general and economists in particular have long pondered the limitations of population growth. Probably best known is Thomas Malthus (Essay on Population, 1789), who raised the theory that when living standards rise, population will rise. As a result, growth in real wages would be used up by more humans to support. He predicted that population would grow until food shortages occurred, and then people would migrate to "the new world."

To be sure, there have been many views counter to Malthus. Utopians (e.g., Condorcet) argued that scientific advances would offset these problems. Marx saw Malthus' argument as a rationale for class exploitation. He argued that depressed wages were not from population growth, but from greedy capitalists. The point here is not to debate capitalism and Marxism (we leave that to economics classes), but rather to show that views of population growth have been central to debates for several centuries.

More recently, Paul Ehrlich of Stanford University (Population Bomb, 1968) predicted gloom and doom for the late 20th century. What happened? To a certain extent, Ehrlich's predictions were heard. Family planning programs developed globally, and environmental legislation escalated. Of course local doomsdays have occurred (and will continue), but there has been more gloom than doom.

If we look at global population growth through history, we note several important aspects in this growth: 1) it took most of history to achieve the first billion, and a little more than 200 years to achieve next 5 billion. 2) doubling times were millions of years for the first billion, but only 130 years for 2 billion, and only 45 years for 4 billion. Most of this growth has been in developing regions, which are ill equipped to handle the resource demands. Not only has population grown, but the rate of population growth has grown. If the rate stabilizes, this is geometric growth. We can think of doubling pennies on each progressive square on a checkerboard. By the time we get to the 64th square, we have riches no man has accumulated (or people that no planet can support). The concern is this: things may get out of our control before we realize the problem.

The next module addresses the demographic transition, which examines trends not only the birth rate but the death rate. The real "problem" with the population explosion is the decline in death rates, especially infant mortality. This has been due to advances in medical technology, but especially from the contribution of improved sanitation. However, even today about 1/3 of the world's annual deaths are in children less than 5 years of age. Children die mostly from lack of food, and lack of safe water. The crucial question is this part of a demographic transition, or do we have enough resources for to support this growth? If we go beyond the carrying capacity of the planet, this growth may result in even more ominous disasters not only for certain countries, but for the planet as a whole.

In this century, if we assume a constant rate of growth, disaster is assured. However, steady state assumptions here are unrealistic, as the next module considers.