Population Issues - Population Trends:The Numbers and Beyond

In mid-1998 the world’s population was estimated at 5.91 billion people and is projected to pass the 6 billion mark in 1999. For 2025, UN demographers cite three population projections -- "low," "medium" and "high" -- each variant based on slightly different assumptions about future birth rates. These three projections range from a low of 7.28 billion to a high of 8.38 billion, the medium variant being 7.82 billion people.

The annual rate of world population growth peaked at about 2 per cent in the early 1960s. Since then, the rate of growth has gradually slowed to less than 1.4 per cent, but the ever-increasing base population meant that the number of people added to the world’s population each year has increased. It is now about 77 million people a year, compared with about 53 million in the 1960s.

Slower population growth rates show that people both want and are having smaller families. The trend towards smaller families has been greatly helped by the wider availability of good-quality family planning services, and easier access to them, especially for women.

There is still a difference between desire and reality. Even in sub-Saharan Africa, where fertility is higher than in any other region of the world, surveys indicate that women want fewer children than they are having. In Kenya, the gap between desired and actual fertility is two children. Yet fertility has already fallen in Kenya, from a high of more than 8 children per woman in the 1970s to under 4.5 children in the second half of the 1990s. Fertility appears to be declining in other sub-Saharan African countries as well, including Botswana, Lesotho, Namibia, (Northern) Sudan and Zimbabwe.

Beyond changes in population growth rates and family size, differences in age structure will also affect the future size of populations in the world’s regions. Among developing countries as a whole, more than one-third of the population is under age 15, compared with less than one-fifth of the population in the industrialized countries. This built-in population momentum means that, even if fertility fell immediately to the replacement level of 2.1 children, about two-thirds of the population growth currently projected would still take place as these young people enter their childbearing years.

Even as birth rates fall, changes in the proportions of both younger and older people are changing the way populations are made up. Over the first decades of the next century there will be a gradual demographic shift towards an older population in all countries. Globally, the largest share of adolescents and other young age groups is and will continue to be in Asia, which has 60 per cent of the world’s population. But since 1980, over 50 per cent of the increase in younger people has been in sub-Saharan Africa.

In the least developed countries, the proportion of adolescents is 43 per cent of the population compared with 34 and 19 per cent, respectively, in the less and more developed countries.

For the less developed regions as a whole, the 15-24 year age group declined from a peak of 20.57 per cent in 1986 to 18.6 per cent in 1998 and continues to decrease as a proportion of total population. Actual numbers in the age group will be 1.06 billion in 2050, 13.6 per cent of total population.

Currently about 74 per cent of the increase in the older population is taking place in developing regions. By 2011 it will be more than 80 per cent. These changes are unprecedented in their size and speed. By 2050, when the total population will increase by 28 million per year, older populations will be growing at about 33 million a year; with 99 per cent of this growth in today’s developing regions.

The highest proportion of people aged 65 and older is found in Europe, and this will continue over at least the next three decades. North America and Oceania also have sizeable proportions of their populations above age 65. Africa and Western Asia have relatively low proportions of older people.
In sub-Saharan Africa, the numbers of those above 65 will increase rapidly while their proportion will increase gradually because of the growth of the base population.

In the more developed regions, the proportion of the population above 65 has increased from 7.9 in 1950 to 14 per cent today and is expected to reach 25.9 per cent by 2050. In all countries with lower levels of fertility, populations above age 65 are projected to double in relative size within the next 30-35 years. In some countries, populations above the age of 85 will more than double in the same period.