![](c05_fig23.jpg)
Figure 5-23 The Human Population Data and estimates from the U.S. Bureau of the Census, the Population Reference Bureau, and the United Nations Population Fund were combined to produce this graph showing the human population from 500 b.c.e. to 2000 c.e. The population began to rise in the eighteenth century and has been increasing at an astonishing rate since 1900.