Overpopulation

As a formal concept, overpopulation means that a human population is too large relative to some sustainable or optimal level. It pertains to global studies because it can be defined either globally or nationally; in each case, it has important consequences for international affairs. If the Earth is judged to be overpopulated, then an effective response has to be global, organized by international bodies or by national governments working together. Any failure of international cooperation would impede efforts to deal with overpopulation and increase the risk of a demographic crisis. If an individual country is judged to be overpopulated, then it can make internal policy responses or perhaps transfer its excess population to countries viewed as underpopulated. Problems of overpopulation may overlap with international migration and associated issues.

In defining and quantifying overpopulation, much depends on how the desirable population is specified. Many assessments of overpopulation have pointed to the physical and environmental limits to population growth: Among the items in limited supply are food, water, living space, agricultural land, minerals, and nonrenewable energy sources. Such assessments have a Malthusian tone, comparing the infinite capacities for population growth with the finite means of subsistence. The desirable population must be sustainable as a longrun steady state and stay within the Earth's carrying capacity. To evaluate overpopulation, one needs to estimate the sustainable population and set it beside actual and projected populations—the task is complex and the results are open to challenge.

Along with sustainability, the desirable population may also be decided by welfare criteria based on income, wealth, consumption, health, education, and other dimensions. Different choices among the dimensions and weightings may give rise to widely differing optima. A population optimum can maximize either average or total welfare—the total method usually gives a larger optimum population with a lower general living standard. Both methods have awkward ethical implications, and recent academic literature on population optimality has sought a middle way between them.

Arguments about overpopulation go hand in hand with a desire to reduce the population growth rate. Neo-Malthusians advocate restrictive population policies such as compulsory limits on family size, stringent birth control, and punitive action against countries that refuse to comply. Their proposals have been much criticized as being authoritarian and misguided. Established models of demographic transition tell us that fertility levels in developing countries will eventually decrease and fall into line with reduced mortality. The peak of world population growth was reached in the 1960s, and since then it has decelerated. Whether these adjustments will suffice to prevent a demographic crisis is debatable, but everyone accepts that they are occurring. If the slow-down in population growth can be ascribed to industrialization (as demographic transition models would suggest), then the “solution” to the population problem may intensify the environmental difficulties from climate change, pollution, and resource scarcity.

Even though we often perceive overpopulation as being global, the policy responses must be implemented locally by national governments. Population policies have been piecemeal and uncoordinated. The strongest measures can be found in countries with a centralized and collectivist political culture, whereas liberal democracies have been wary of taking overt action. Any population policy raises ethical disquiet over reproductive rights, birth control, gender equality, family relationships, and conflicts with welfare programs. National [Page 1286]governments may have the option of using international migration to alleviate population pressures, but recent migration from less developed to developed countries has seldom been interpreted as a remedy for overpopulation. To argue thus would imply that the recipient countries are underpopulated, which sits uneasily with the high population densities in many developed countries. Large-scale international migration as a response to overpopulation would invoke the barriers and social problems that stem from cultural, linguistic, ethnic, and religious differences.

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