In 1900, the world's population was approximately 1.5 billion. Since 1960, world population has grown by approximately 5.5 billion people. Given current fertility levels and growth rates, global population is expected to reach 9.7 billion people by 2050. Historical processes of global population growth also need to be understood in relation to regional differences in population growth and the prospects for future population change. Changing patterns of population growth have also been the subject of considerable debate, including Malthusian and optimist positions, concerning the immediate impacts of population growth as well as the long‐term implications of growing world population.
