The scariest thing about Halloween this year was the announcement that world population has reached seven billion. It is truly horrifying. Although I’ve written earlier about one of the optimistic aspects of human demography, the so-called demographic transition whereby wealthier, better-educated societies typically experience lower birth rates, that’s pretty much the only positive thing I can see about the world’s ever-increasing population: the fact that it might eventually slow down!
There is a real danger that some states may never emerge from what might be termed the “demographic-economic-environmental trap.” In such cases, rapid population growth contributes to increased demands on natural and socioeconomic systems, which are then overtaxed and begin to collapse. People commonly respond with higher birth rates, which in turn produce yet more ecological and socioeconomic pressure, which ultimately impoverishes the land and the people, leading to catastrophic mortality, notably from starvation and epidemics, and possibly direct violence as well.
Population levels, ecological factors, and economic conditions are all intimately related. Thus, every environment can be said to have a “carrying capacity,” the number of people who can be supported by the soil, forests, grassland, croplands, water and other resource supplies of that region. If demand exceeds carrying capacity, the effect is like “mining capital” rather than “living off one’s interest”: It cannot be sustained for long.
For example, in many areas of the world, wood is used for fuel. More people result in more demand for wood, which leads to cutting, perhaps in excess of the amount that grows annually. As forests dwindle, wood becomes scarce and expensive, adding to the misery of the poor, while the deforestation itself seriously diminishes wildlife values, contributes to the greenhouse effect, and generates erosion and downstream flooding. (Devastating floods in Bangladesh have become commonplace, periodically killing tens of thousands and making hundreds of thousands of people homeless, due to the destruction of forests in the foothills of the Himalayas, above that country.)
The forest lands of India in 1982 could support an annual harvest of 39 million tons of wood, whereas fuelwood demand was for 133 million tons. The gap—94 million tons—has been met by overcutting (which compromised future forest production), and by burning cow dung, which robbed the soil of needed fertility. If Indian forests continue to shrink while its population expands, this gap will become even larger, with possibly irrevocable long-term effects.
A similarly tragic pattern can take place with regard to supplies of fresh water (if demand exceeds the recharge rate of underground aquifers, lakes and reservoirs, or the flow rate of rivers, etc.) The productivity of grasslands or croplands can be similarly abused, with serious consequences. A study of nine countries in southern Africa, for example, found that cattle exceeded the carrying capacity of local grasslands by 50 to 100 percent. It should be clear that these problems cannot be solved simply by cutting down more trees, digging deeper wells (which temporarily provides more water but eventually lowers the water table and exhausts aquifers), adding more fertilizer, and the like. And even though the acute problem of world hunger is principally one of distribution rather than production, even a distribution problem is exacerbated by the presence of too many mouths, to whom food must somehow be distributed. Underlying this, of course, is the problem of sustainability.
Another significant consequence of the demographic-economic-environmental trap is the production of large numbers of so-called eco-refugees, people who are forced to leave their ancestral homes because of environmental degradation. Land-hungry farmers are increasingly driven onto wildlife preserves and marginal land that is highly erodable and easily destroyed. The result is “desertification,” a process that is distinct from drought. In this case, overgrazing, overplowing, and deforestation destroys the productivity of the soil, on which whole ecosystems depend.
The process is accentuated by natural drought, to which weakened and overcrowded people are especially susceptible. The increasing numbers of eco-refugees congregate in cities and refugee centers, where they rely on government assistance, are highly susceptible to disease and—as has occurred in drought-stricken sub-Saharan Africa—massive starvation when and if relief efforts run into political, economic, or logistic difficulties.
Uncontrolled population growth in subsistence economies not only threatens the country’s environment, but also its social and economic system. Universal public education becomes virtually impossible when school systems are drowned beneath a tidal wave of youngsters. When population is constant or declining slightly (as in Germany or Switzerland), a 2-percent increase in economic growth results in increased overall per-capita prosperity; when the population increases by 3 or 4 percent, that same 2-percent economic growth results in painfully declining living standards for most people, such that the world is increasingly divided into countries where population growth is slow or nonexistent and where living conditions are improving, and those where population growth is rapid and living conditions are deteriorating or in imminent danger of doing so.
It is difficult to make a cogent case that more people are needed, in any part of the world. Those regions that we generally consider to be “unpopulated” usually possess few people because in fact the land and its climate can only support small populations. Deserts, high mountain slopes, or low-lying marsh or swampland that is regularly inundated by floods, cannot—and should not—be heavily populated.
There are no Shangri-las on the planet Earth: regions that are currently unpopulated, but that could provide idyllic, well-balanced lives for substantial numbers of people. Moreover, “Third World” countries are already dangerously overextended in their ability to care for their current population, while per capita, resource demands on the relatively affluent countries are substantially higher. With 5 percent of the world’s population, the U.S., for example, uses about 40 percent of the world’s nonrenewable resources, which means that each of us takes eight times our share.
There are few easily identified villains in this unfolding ecological and human disaster, but high on the list I would place those institutions that consistently block availability and distribution of birth control. I suggest that by far the greatest sin of the Catholic Church, for example, isn’t its involvement in and cover-up of child abuse, or even the Crusades or the Inquisition, but rather, its continuing and unforgivable resistance to an enlightened population policy.
