The United Nations today reduced its estimate of what the world's population will be in 2050 by 400 million, primarily because of the impact of the AIDS epidemic and lower than expected birth rates.
At the dawn of the new Millennium, the UN Population Division forecast that 9.3 billion people would inhabit the Earth at mid-century but a new revision of the estimate projects a lower population of 8.9 billion.
About half the 400 million drop is a result of an expected increase in the number of deaths, primarily from AIDS, the forecast said. The other half is due to a reduction in the projected number of births, mainly as a result of lower expected fertility rates.
"For the first time, the United Nations Population Division projects that future fertility levels in most developing countries will likely fall below 2.1 children per woman, the level needed to ensure the long-term replacement of the population, at some point in the 21st century," said the forecast.
By 2050, it projects that three out of four countries in less developed regions will have fertility levels below replacement levels.
The report, "World Population Prospects: The 2002 Revision," confirms key conclusions from previous revisions about population growth.
Despite expectations of lower fertility levels and increased death risks, global population is still expected to increase from 6.3 billion today to 8.9 billion in 2050, it said.
The Population Division warned, however, that the latest projections depend on ensuring that couples have access to family planning.
If fertility in all countries remained at current levels, it said, "the total population of the globe could more than double by 2050, reaching 12.8 billion."
But based on the new estimates, the forecast predicts that the population of more developed regions, currently at 1.2 billion, will change little during the next 50 years.
Thirty three countries are projected to be smaller at mid-century than today Japan losing 14 per cent of its population, Italy 22 per cent of its population, and Bulgaria, Estonia, Georgia, Latvia, Russia and Ukraine between 30 and 50 per cent of their populations.
By contrast in less developed regions, the population is projected to rise steadily from 4.9 billion in 2000 to 7.7 billion in 2050, according to the forecast.
The populations of Burkina Faso, Mali, Niger, Somalia, Uganda and Yemen, are projected to quadruple because of expected annual growth rates of more than 2.5 per cent between 2000 and 2050, it said.
In the most populous countries, large population increases are expected even if fertility levels are projected to be low.
Between 2000 and 2050, the forecast said eight countries are expected to account for half the world's projected population increase India, Pakistan, Nigeria, the United States, China, Bangladesh, Ethiopia and Congo.
The 2002 Revision indicates a worsening of the impact of the HIV/AIDS epidemic in terms of disease, deaths and population loss.
In the current decade, 46 million people are expected to die of AIDS in the 53 most affected countries, "and that figure is projected to ascend to 278 million by 2050," the forecast said.