Just two years ago the Population Division forecast a world population of 9.3 billion by midcentury. The new report, released Feb. 26, lowers that estimate to 8.9 billion. (The figure is the medium-level variant, which is considered the most probable estimate.) World population is now estimated at 6.3 billion.
The Population Division concedes that fertility levels in most developing countries will likely fall below the replacement rate of 2.1 children per woman during the coming century. In fact, the medium variant projection forecasts that by midcentury three out of every four countries in the less developed regions will be at below-replacement fertility. This is a well-established phenomenon in economically advanced countries, and the report now acknowledges the dramatic fall in fertility in other nations.
The U.N. Revision also forecasts a worsening of the impact of AIDS, even as it assumes that HIV infections will decline significantly after 2010. During this decade, AIDS-related deaths are expected to reach 46 million. By 2050 the cumulative total of such deaths could soar to 278 million. Outright reductions in population are projected for Botswana, Lesotho, South Africa and Swaziland.