Introduction: World Population and Agricultural Productivity

Abstract

For most of the 16000 years of human history, there have been less than 300 million people on the earth, but in the last 200 years a sustained and rapid increase in population has taken place (Salk and Salk 1981). The number passed 1 billion (1 x 10⁹) in 1850, 2.5 billion a century later, and the remainder of the 20th century will see the population rise from the current level of about 5.3 billion to over 6 billion (Table 1.1). In the longer term, it is predicted that the human population will reach a distinct plateau (Salk and Salk 1981); these predictions are based on the change in populations in the more developed countries and analysis of animal populations. This plateau will occur at a value of between about 10 and 14 billion people (see Sadik 1990).