Population may stabilise at 9 billion, says UN

Posted: 9 November 2004

Author: John Rowley

In a controversial move, the UN Population Division has extended its view of world population trends beyond its previous long-term projections - to look ahead for 300 years. This produces a 'medium' scenario which sees world population rising from 6.1 billion in 2000 to around 8.9 billion in 2050, peaking at 9.22 billion in 2075 and stabilising at around 9 billion in 2300.

It justifies what demographers agree is an impossible task, given all the uncertainties of birth and death rates beyond the next 50 years or so, on the grounds that "it will allow for the eventual stabilisation of the world's population - at least in one scenario." It stresses that its projections are not forecasts but extrapolations of present trends. The uncertainty of projecting over a period of 300 years is shown by the scenarios for high and low growth in human numbers. These put the planet's population in 2300 at anything beetween 36.4 billion and 2.3 billion.

Estimated world population: 1950-2000, and projections: 2000-2300. Source: UN Population Division (2004)
Estimated world population: 1950-2000, and projections: 2000-2300. Source: UN Population Division (2004)
Estimated world population: 1950-2000, and projections: 2000-2300Source: UN Population Division (2004)
The report sees developing countries, where large families are still common, moving towards the two-child norm - though sometimes over decades - while developed countries with below replacement fertility, move back towards it. However, only slight variations from the eventual two-child global norm will have big repercussions, the UN warns.

It projects that all countries will have reached replacement level fertility by 2175, with past fertility trends continuing to effect the picture for another 50 years. But a third of a child above the norm would result in a population four times bigger than the medium projection, while a fall of 0.2 of a child below replacement level, would bring down world populution in 2300 to only a quarter of the main projection.

The theory behind this medium projection is that all countries will go through the same basic trajectory, with fertility rates falling, in both developed and developing countries, to below the replacement level of 2.1 children per woman and then moving back to a stable situation where numbers rise only very gradually.

Aging world

This process of population rise, fall, decline and rise again, will result in a global demographic map with areas that shrink and stretch at different times in the next three centuries, the report says.

Europe and Africa, for example, will be on very different paths. Europe will hit the low point in its growth in 2050, Africa not until 80 years later, after all the other major areas. Europe's share of of world population will drop by half, in this century, from 12 per cent to 6 per cent.

By 2300, India,China and the United States will remain the most populous countries - though India is expectes to overake China bu 2050 when it will have a population of 1.53 billion. They will be followed by Pakistan and Nigeria - and may be joined in the top twenty by Yemen and Uganda.

As life expectancy continues to grow, the report says people could expect to live to 96 by 2300: giving 31 years of leisure if the retirement age of 65 stays unchanged. In Japan, life expectancy is projected to grow to more than 106.