África vai ter um quarto da população mundial

World population peaks at 9.22 billion in 2075. Population therefore grows slightly beyond the level of 8.92 billion projected for 2050 in the 2002 Revision, on which these projections are based. However, after reaching its maximum, world population declines slightly and then resumes increasing, slowly, to reach a level of 8.97 billion by 2300, not much different from the projected 2050 figure. This pattern of rise, decline, and rise again results from assumptions about future trends in vital rates: that, country by country, fertility will fall below replacement level—though in some cases not for decades—and eventually return to replacement; and that, country by country, life expectancy will eventually follow a path of uninterrupted but slowing increase. With alternative assumptions about fertility, long-range trends could be quite different. With long-range total fertility 0.3 children above replacement, projected world population in 2300 is four times as large as the main projection; with total fertility 0.2 children below replacement, world population in 2300 is one-quarter of the main projection. Regions and countries will follow similar demographic paths in the long run, given similar assumptions for different countries about longrange vital rate trends. However, because initial assumptions differ, and because this gives rise to slight variations in trends, countries and regions will not be exactly alike, even by 2300. In fact, what are today considered more developed and less developed regions will still be demographically distinguishable, with regard, for instance, to life expectancies and proportions at advanced ages. In addition, regions and countries will go through critical stages of growth—zero growth, subreplacement fertility, a return to positive growth—at different points in the future, giving rise to a global demographic map with areas that shrink and stretch at different times in the next three centuries. Europe and Africa will be particularly out of phase. Europe will hit its low point in growth in 2050, Africa not till 80 years later, after all other major areas. From 2000 to 2100, Europe’s share of world population is cut in half, 12.0 to 5.9 per cent, while Africa's almost doubles, from 13.1 to 24.9 per cent. While shares of world population for major areas will rise and fall over the following two centuries, the distribution by 2300 will resemble that in 2100. Smaller regions within continents exhibit divergent patterns. For instance: • Three African regions—Eastern Africa, Middle Africa, and Western Africa—will grow unusually fast in comparison to every other region through 2100, even though total fertility will be close to replacement by 2050. • Southern Africa is seeing a decline in life expectancy to a lower level than anywhere else, but life expectancy will rebound, rise quite rapidly, and overtake other African regions. • Asian regions will grow fastest to the west, slowest to the east, but in every case with growth rates, at least up to 2100, below Eastern, Middle and Western Africa. By 2100, Asia, instead of being four-and-a half times as populous as Africa, will be only 2.2 times as populous. • Latin America and the Caribbean is the most homogenous major area, with most of its regions following relatively parallel fertility and life expectancy paths. • Northern America is unusual as the only region that will not experience negative growth, mainly due to projected migration up to 2050. (No migration is incorporated in projections beyond that date.) • Europe, like Asia, will experience higher growth to the west, lower growth to the east. PROJECÇÔES das Nações Unidas