Para os que gostam de saber os números da população mundial, aqui ficam alguns excertos do relatório de 2006 das Nações Unidas (texto completo disponível AQUI).
"...the world population will likely increase by 2.5 billion over the next 43 years, passing from the current 6.7 billion to 9.2 billion in 2050. This increase is equivalent to the size that the world population had in 1950 and it will be absorbed mostly by the less developed regions, whose population is projected to rise from 5.4 billion in 2007 to 7.9 billion in 2050. In contrast, the population of the more developed regions is expected to remain largely unchanged at 1.2 billion and would have declined were it not for the projected net migration from developing to developed countries, which is expected to average 2.3 million persons a year after 2010."
"Underlying these varied patterns of growth and changes in the age structure are distinct trends in fertility and mortality. Below-replacement fertility prevails in the more developed regions and is expected to continue to 2050. Fertility is still high in most of the least developed countries and, although it is expected to decline, it will remain higher than in the rest of the world. In the rest of the developing countries, fertility has declined markedly since the late 1960s and is expected to reach below-replacement levels by 2050 in the majority of them."
"Future population growth is highly dependent on the path that future fertility takes.In the medium variant, fertility of the world declines from 2.55 children per woman today to slightly over 2 children per woman in 2050. If fertility were to remain about half a child above the levels projected in the medium variant, world population would reach 10.8 billion by 2050. A fertility path half a child below the medium variant would lead to a population of 7.8 billion by mid-century. That is, at the world level, continued population growth until 2050 is inevitable even if the decline in fertility accelerates."
Fonte: World Population Prospects The 2006 Revision: Executive Summary - United Nations (2007)