Paul Ehrlich & Anne Ehrlich
The Population Explosion

The Population Explosion vividly describes how the Earth's population, growing by 95 million people a year, is rapidly depleting the planet's resources, resulting in famine, global warming, acid rain, and other major problems. Paul and Anne Ehrlich also clearly and concisely point to immediate action that will lessen the threat of ruin and begin to build a more peaceful, sane, and secure world.

All too often, overpopulation is thought of simply as crowding: too many people in a given area, too high a population density. For instance, the deputy editor in chief of Forbes magazine pointed out recently, in connection with a plea for more population growth in the United States: "If all the people from China and India lived in the continental U.S. (excluding Alaska), this country would still have a smaller population density than England, Holland, or Belgium."

The appropriate response is "So what?" Density is generally irrelevant to questions of overpopulation. For instance, if brute density were the criterion, one would have to conclude that Africa is "underpopulated," because it has only 55 people per square mile, while Europe (excluding the USSR) has 261 and Japan 857. A more sophisticated measure would take into consideration the amount of Africa not covered by desert or "impenetrable" forest. This more habitable portion is just a little over half the continent's area, giving an effective population density of 117 per square mile. That's still only about a fifth of that in the United Kingdom. Even by 2020, Africa's effective density is projected to grow to only about that of France today (266), and few people would consider France excessively crowded or overpopulated.

When people think of crowded countries, they usually contemplate places like the Netherlands (1,031 per square mile), Taiwan (1,604), or Hong Kong (14,218). Even those don't necessarily signal overpopulation--after all, the Dutch seem to be thriving, and doesn't Hong Kong have a booming economy and fancy hotels? In short, if density were the standard of overpopulation, few nations (and certainly not Earth itself) would be likely to be considered overpopulated in the near future. The error, we repeat, lies in trying to define overpopulation in terms of density; it has long been recognized that density per se means very little.

The key to understanding overpopulation is not population density but the numbers of people in an area relative to its resources and the capacity of the environment to sustain human activities; that is, to the area's carrying capacity. When is an area overpopulated? When its population can't be maintained without rapidly depleting nonrenewable resources (or converting renewable resources into nonrenewable ones) and without degrading the capacity of the environment to support the population. In short, if the long-term carrying capacity of an area is clearly being degraded by its current human occupants, that area is overpopulated.

By this standard, the entire planet and virtually every nation is already vastly overpopulated. Africa is overpopulated now because, among other indications, its soils and forests are rapidly being depleted and that implies that its carrying capacity for human beings will be lower in the future than it is now. The United States is overpopulated because it is depleting its soil and water resources and contributing mightily to the destruction of global environmental systems. Europe, Japan, the Soviet Union, and other rich nations are overpopulated because of their massive contributions to the carbon dioxide buildup in the atmosphere, among many other reasons.

Almost all the rich nations are overpopulated because they are rapidly drawing down stocks of resources around the world. They don't live solely on the land in their own nations. . . . they are spending their capital with no thought for the future.

It is especially ironic that Forbes considered the Netherlands not to be overpopulated. This is such a common error that it has been known for two decades as the "Netherlands Fallacy." The Netherlands can support 1,031 people per square mile only because the rest of the world does not. In 1984-86, the Netherlands imported almost 4 million tons of cereals, 130,000 tons of oils, and 480,000 tons of pulses (peas, beans, lentils). It took some of these relatively inexpensive imports and used them to boost their production of expensive exports--330,000 tons of milk and 1.2 million tons of meat. The Netherlands also extracted about a half-million tons of fishes from the sea during this period, and imported more in the form of fish meal.

The Netherlands is also a major importer of minerals, bringing in virtually all the iron, antimony, bauxite, copper, tin, etc., that it requires. Most of its fresh water is "imported" from upstream nations via the Rhine River. The Dutch built their wealth using imported energy. Then, in the 1970s, the discovery of a large gas field in the northern part of the nation allowed the Netherlands temporarily to export as gas roughly the equivalent in energy of the petroleum it continued to import. But when the gas fields (which represent about twenty years' worth of Dutch energy consumption at current rates) are exhausted, Holland will once again depend heavily on the rest of the world for fossil fuels or uranium.

In short, the people of the Netherlands didn't build their prosperity on the bounty of the Netherlands, and are not living on it now. Before World War II, they drew raw materials from their colonies; today they still depend on the resources of much of the world. Saying that the Netherlands is thriving with a density of 1,031 people per square mile simply ignores that those 1,031 Dutch people far exceed the carrying capacity of that square mile.

This "carrying-capacity" definition of overpopulation is the one used in this book. It is important to understand that under this definition a condition of overpopulation might be corrected with no change in the number of people. For instance, the impact of today's 665 million Africans on their resources and environment theoretically might be reduced to the point where the continent would no longer be overpopulated. To see whether this would be possible, population growth would have to be stopped . . . Similarly, dramatic changes in American lifestyle might suffice to end overpopulation in the United States without a large population reduction.

But, for now and the foreseeable future, Africa and the United States will remain overpopulated and will probably become even more so. To say they are not because, if people changed their ways, overpopulation might be eliminated is simply wrong--overpopulation is defined by the animals that occupy the turf, behaving as they naturally behave, not by a hypothetical group that might be substituted for them. [pp. 37-40]

(The above is a very conservative estimate which expects the growth rate to decrease to less than .5% even though it hasn't been at that level in the past. The annual rate has fluctuated between 1.27% (never below) and 2.2% since the 1950s. If the average rate of the 1980s is used instead, the 2000 population will more than double by 2050. It doesn't get much better if the average rate of the 1990s is used as there wasn't a significant downturn in the rate from the 80s in the 90s.)