The balance of the global population is shifting too. A hundred years ago, there were three times as many Europeans as Africans. Now there are three times as many Africans as Europeans. The biggest population explosion came after the Second World War, when death rates in developing nations declined sharply. Since then, education and development programmes have steadily reduced fertility rates.
Future growth is difficult to predict.
The problems that would cause are so enormous that it's almost impossible to believe we would realistically reach that figure. The UN's low-end estimate of population trends is that world numbers would decrease to only 3.6 billion by 2150. Its medium estimate of fertility puts the 2050 figure at around 9 billion people, growing to 10.8 billion by the year 2150 and ultimately stabilising at 11 billion by the year 2200. With 30 million people infected worldwide, the disease is cutting average life expectancy by as much as ten years in the worst-hit countries. The China Solution.