Older people will outnumber young

By Bernard Besserglik

PARIS (AFP): Having broken through the six billion threshold in the closing weeks of the 20th century, the world's population is likely to stand at around nine billion by 2050, but the figure for the end of the 21st century is anyone's guess.

Fears of a demographic catastrophe are misplaced, most experts believe, but other dangers lurk, including social and economic strains caused by an ageing and declining population in many regions and the ravages that man-made climate changes could bring about.

The key factors that will shape population issues in the coming century is the sharp fall in fertility and mortality rates that set in some 50 years ago.

Average fertility worldwide, according to United Nations Population Fund figures, has slumped from five children per woman in the 1960s to 2.7 now. Meanwhile average global life expectancy over the past half-century has risen from 46 to 66 years.

And while only a few countries so far have declining populations, already 61 countries, representing 44 percent of the world's inhabitants, have below-replacement fertility rates (fewer than 2.1 live births per woman).

The median estimate in the UN Population Division's latest projection for 2050 is a global population of 8.9 billion. Other estimates, depending on the assumptions made regarding fertility rates, range from 7.3 to 10.7 billion.

The UN has revised downwards a median estimate of 9.4 billion made only four years ago, and even the revised estimate is probably on the high side, according to Tim Dyson, professor of Population Studies at the London School of Economics.

Fertility rates in many regions are falling much faster than expected and are likely to remain low, he warns.

Dyson divides the world into three contrasting blocs: Europe and those parts of Asia, notably Japan, which will face problems of ageing and shrinking populations; areas of continuing growth such as West and Central Africa and the Indian subcontinent; and areas such as East Africa where HIV and AIDS will mean low fertility and high death rates.

Even in developed countries, low fertility could have potentially disastrous consequences, he warns, pointing to Spain and Italy as countries where fertility is far below the replacement rate.

Europe's share of the world population, 20 percent in 1960 and already down to 13 percent, will fall to around 7 percent in 2050, according to UN estimates. Asia's share, currently 60 percent, will probably remain stable, as will that of North America (5 percent) and Latin America (9 percent).

The problem with the expected population growth, Jacques Vallin of the French Institute of Demographic Studies notes, is that "most of it will take place among the populations which are least able to support it, namely poor and developing countries."

Thus Africa will see its share of world population increase to 20 percent in 2050, compared with 13 percent at present and only 9 percent in 1960. Thus the HIV-AIDS pandemic, despite its terrible toll, will cause scarcely a dent in that continent's population curve.

Meanwhile, thanks to advances in medicine and improvements in living conditions generally, people will live better and longer, to the extent that worldwide, by 2050, the over-60s are likely to outnumber the under-15s.

The proportion of the population aged 60 or over, currently around 10 percent, will rise to 22 percent in 2050 and could reach 30 percent by the end of the century, according to UN experts.

The social and political implications of this relentless greying of the population, in which increasing numbers of elderly people will depend on pensions financed by a proportionally reduced productive sector, are immense and have yet to be grasped by the world's leaders, warns Michel Allard, an expert on ageing at the Foundation Ipsen in Paris.

The first shocks can be expected in the decade 2010-2020, as the postwar generation of "baby-boomers" reach retirement age, he predicts.

The quality of life in the 21st century will depend on numerous factors, with some experts arguing that increased productivity will enable resources to keep pace with population growth and others warning that over-population remains a threat to the planet.

Dyson expressed optimism "over the medium term," at least the next 25 to 30 years, though he added that some problems that were likely to arise, such as global warming, war and new forms of killer viruses, were beyond his remit and could upset predictions.

The central issue for the coming century was sustainability, he said: can the world sustain population levels in excess of eight billion in the long term given the damaging effects of human activities on the world environment?

The size of the world's population in 2100 thus depends not only on demographic trends but on efficient husbanding and distribution of the world's resources.