The environmental challenge - population control

The population of the world has multiplied by a factor of seven since 1750, tripled since 1900 and doubled since 1950. Its rate of growth accelerated throughout this century, peaking in the mid-1960s at 2.1 per cent per year and then declining to the current rate of 1.7 per cent per year. The rapid population growth since World War II, unprecedented in recorded history, caused grave concern and controversy about the ability of the global economy and ecology to sustain the increased numbers.

Classical economists like Thomas Malthus (1766-1834) believed that, as growing population made land increasingly scarce, rising food prices would eventually choke off further economic and demographic growth and that this would lead to what they termed the "stationary state". For them, natural resource constraints were at the heart of the problem. Yet while the classical economists stressed the central role of land in the economy, the importance of land has dwindled in the modern world. The share of the labour force in agriculture is declining in most areas and the possibilities for increasing the output from a given amount of land, through increased inputs of fertilizer, pesticides, new seed varieties, irrigation and better training, appear very great.

By the 1980s, policy-makers were in a state of confusion. Was population growth good or bad? Did it matter at all? Would expenditure on family-planning programmes lead to more rapid economic development?

This uncertainty led to systematic attempts to assess our knowledge, including major projects by the World Bank and the United States National Academy of Sciences. In the mid-1980s, these assessments revealed a surprising degree of agreement among economists. While few of them accepted the view that population growth was good for development, the consensus was that it mattered less than had previously been thought. Earlier studies, it was believed, had failed to appreciate the flexibility of the economic system.

Sounding the alarm

While economists were playing down the effects of population growth, ecologists and environmentalists like Paul Ehrlich and Garrett Harding were sounding the population alarm. They pointed out that the biosphere provided essential inputs to economic activity and warned that its limits and fragility placed bounds on sustainable levels of economic activity and that these bounds had already been overstepped. The global economy was consuming ecological capital with careless extravagance rather than living off the interest.

Ehrlich and Hardin had been expressing these views since the 1960s at least and their views were incorporated into a system analysis model in the Club of Rome report "The Limits to Growth". This report, which attracted worldwide attention in the early 1970s, came to the conclusion that global collapse was imminent and inevitable unless fundamental changes were made and that catastrophe was inherent in the structure of socio-economic and ecological relationships.

Social scientists soon rejected the Club of Rome approach in favour of careful analysis of each relationship. In the 1980s, however, a flood of environmental problems added new urgency to the ecologists' position. Hot summers, drought, acid rain, polluted waters, famine and holes in the ozone layer seemed to confirm their predictions, leading to heightened concern about population growth.

Ecologists, however, had presented a broad array of reasons to end or reverse population growth; some of these were less solid than others. Many of the older ideas about the economic consequences of population growth were again put forward. These were unconvincing since they were not supported by the more recent research. Ecologists had also been issuing warnings about the impending exhaustion of minerals, but economists such as Julian Simon countered by showing that the real prices of most minerals had been falling historically, not rising, and that the total costs of natural resources had not been rising as a share of national output. Petroleum prices had also tended to fall, if increases caused by OPEC are excluded. In 1980, Simon wagered Ehrlich that mineral prices would decline in real terms during the following decade. In 1990 Simon won this well-publicized bet and collected his money. The historical record illustrates the substitution of more abundant resources for scarce ones in response to relative price changes. It exemplifies flexible economies responding to incentives communicated through market prices.

Some of the ecologists' other claims have also appeared to be premature or exaggerated. For example, real food prices have historically fallen and per capita food production has increased. The incidence of famines has diminished, not increased, and modern famines often arise from wars or mistaken policies rather than from deficiencies of agricultural production due to population growth.

"The tragedy

of the commons"

Yet many of the ecologists' most important warnings appear correct, particularly those concerning renewable resources -- air, water, fisheries, land, forest cover, the ozone layer and species diversity. These resources can sustain a certain level of use without diminution, but over-use leads to their damage or destruction. Furthermore, most of them lie outside the market economy and may be used cost free. This means that economic agents -- individuals or firms -- can benefit from cheap disposal of pollutants without bearing the costs of environmental degradation, the costs being passed on to society as a whole. As a result, economic incentives encourage over-use. The automatic signalling mechanism of market prices is impotent and price changes serve neither as an incentive nor as a signal of increasing scarcity.

For some resources, such as forest cover, there is little incentive even for national policies, because the costs of policies are borne locally while the benefits are shared globally. Hardin called this type of problem "the tragedy of the commons", and the name has stuck. Although traditional communities with common property resources have typically managed then effectively, these arrangements are vulnerable to the forces of economic development. In any event, modern environmental problems transcend local communities, nations and even continents.

Damaging over-use of renewable resources is intensified by population growth. Although, in principle, over-use can be prevented by appropriate policies and institutional arrangements, in practice this has been difficult to achieve. The situation is complicated because population is only one of several contributory factors. Per capita income growth and changing technologies, for example, also play important roles, but in a given situation it is difficult to assess how much is due to their influence and how much is due to population growth. Nevertheless, whether renewable resources are well managed or not, population growth means that less of their services will be available to each individual.

Worries about population growth have thus come full circle -- from the classical concern for limited land, to emphasis on physical capital, to more recent emphasis on human capital and the ameliorative influence of competitive markets and back once again to the natural constraints. This time, however, the concern is for renewable resources, most of which fall outside the market. For some, the urgency of population control on ecological grounds is obvious. Others remain sceptical. Research on links between population growth and the environment is under way, and there is hope for a better understanding of these links in coming years.

Because many of the ecological costs of population growth are global, the ecological incentives to restrain population for national gain may be weak. This is another tragedy of the commons, which can only be removed by international collaboration.

COPYRIGHT 1992 UNESCO
COPYRIGHT 2004 Gale Group