Fertility,mortality and disease

According to the US Census Bureau, the world's population reached six billion in the summer of 1999. This was three and a half times the number at the start of the twentieth century and twice the number in 1960. The numbers are expected to continue to increase at the present rate, and the prospect is causing widespread anxiety. The causes of the population explosion are to be found both in modern and in prehistoric circumstances. A hiatus of disease occurred during the twentieth century, which greatly reduced premature mortality, and we should be fearful that this will not continue. To staunch the growth of population and to prevent the resurgence of disease, some radical changes in social behaviour are required.