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Nature Gallery (Global Trends)

Population Growth

Overpopulation
The major cause of most environmental problems is the rapidly growing human population, now at 5.85 billion (1997) people worldwide. A quarter of a million babies are born each day—90 million each year. By the end of the century, the global population will be six billion, and in another 50 years, it will be ten billion. Even if fertility declines to the rate of two children per woman, the overall numbers will rise at least another three billion. This is because the current world population is very young on average and has many years of reproductive life ahead.

Meeting the basic needs of all these people—for food, housing, heat, energy, clothing, and consumer goods—places tremendous demands on the earth’s natural resources. Without technological and land-use changes, the demands are bound to grow.
Population pressures on the environment are determined as much by distribution of people as by total population numbers. Ninety per cent of current population growth takes place in developing countries, where 84 per cent of the world’s people will live by the year 2025. Kenya and Iraq, for example, are growing at a rate of nearly 4 per cent per year, doubling their numbers every 20 years. In developed countries such as Japan and France, it would take nearly 400 years to double populations.

Industrialized countries, with higher living standards and greater numbers of cars, produce far more air pollution and greenhouse gases than developing countries. Developed countries also contribute to overfishing and deforestation. But these countries can reduce serious environmental hazards by using technology such as smokestack scrubbers, emission systems, and waste-water treatment plants. Although developing countries consume a far smaller percentage of the world’s resources per person, the sheer numbers of people can quickly deplete soil, forests, and waterways. Expensive energy-efficient or clean-up technologies are economically impractical for these countries.

Urbanization
Another global population trend, rapid urbanization, may be a positive development for the environment. Three-quarters of the people in the industrialized world and one-third in the developing world now live in urban centres. By 2025, two-thirds of the world’s population will be urban. Although urban areas generate higher concentrations of pollution, they also deliver services, such as water and electricity, much more efficiently.

Urbanization also tends to lower birth rates. This occurs because people who live in cities, especially women, have higher levels of education and income, factors that correlate closely with decreases in birth rates. In Taiwan and South Korea, for instance, increasing affluence and rising education levels have resulted in smaller families, and population growth has fallen by half. Governments and private organizations are also working to control population increases by distributing family-planning information and through systems of taxes and other incentives that discourage large families. However, education and money only really play a contributory role, since the one factor that is directly related to birth rates is the capacity of a woman (in terms of knowledge and the necessary contraceptive materials) to manage her own fertility. Around three-quarters of the women who want to plan the number and spacing of the children they give birth to do not have access to family planning materials. Another key factor that influences birth rates is a woman's confidence that the children she bears will survive and be healthy.

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