In 2017, the global population was estimated at 7.6 billion people (figure 4.1) and is projected to increase to 9.8 billion by 2050. Asia’s relatively large population, 4.5 billion of the world total of 7.6 billion, coupled with rising urbanization and industrialization, is a recent driver of resource use. Africa’s total population in 2017 was estimated at 1.2 billion and projected to increase to almost 4.5 billion by 2100 (figure 4.2). The projected rapid growth rates are due to the large youth bulge, which means that even as population growth rates in other regions taper off, Africa will be the only region experiencing substantial population growth, with its share of the global population expected to increase from 16 per cent in 2017, to 20 per cent in 2030 and 46 per cent in 2100. Of the world’s 31 megacities, 24 are located in less-developed regions and five are in Africa, excluding North Africa.