Thomas Malthus first published his \u201cEssay on the Principle of Population\u201d\u009d, in which he forecast that population growth would outstrip the world\u2019s food supply, in 1798. His timing was unfortunate, for something started happening around then which made nonsense of his ideas. As industrialisation swept through what is now the developed world, fertility fell sharply, first in France, then in Britain, then throughout Europe and America. When people got richer, families got smaller; and as families got smaller, people got richer.<\/p>\n
Now, something similar is happening in developing countries. Fertility is falling and families are shrinking in places\u201d\u201d such as Brazil, Indonesia, and even parts of India\u201d\u201dthat people think of as teeming with children. As our briefing shows, the fertility rate of half the world is now 2.1 or less\u201d\u201dthe magic number that is consistent with a stable population and is usually called \u201cthe replacement rate of fertility\u201d\u009d. Sometime between 2020 and 2050 the world\u2019s fertility rate will fall below the global replacement rate.<\/p>\n