The IIASA world population scenarios to 2030

This chapter provides population projections for 12 world regions based on eight different scenarios which vary in fertility mortality and migration assumptions and two paths (high and low). One central scenario is presented. Projections are generally given up to the year 2030 but some assumptions are used to illustrate impacts up to 2050. This chapters scenarios differ from projections published by the World Bank and the UN in trying to include environmental impacts. Projections show that future world population growth is uncertain. The expected global population by 2030 will probably exceed 8 billion people and could possibly reach 11 billion. The central scenario projects a population of 9.4 billion in 2030. High fertility scenarios with low mortality yield a projected population of 15 billion by 2050. The only scenario with a leveling off of population size and even a slight decline before 2050 was one with low fertility and high mortality. Population growth trends varied widely by region. The central scenario yielded a population increase of 35% in North America a 75% increase in South America and a 50% increase in China. Population is expected to double in North Africa South Asia Central America and the Caribbean. The highest population growth is generated by a scenario with high fertility low mortality and low migration. Under the central scenario population concentration would shift from 22% in industrialized countries in 1990 to only 14% in 2030. Africa would increase its share of world population the most rapidly. Africa is expected to have 12% of world population in 1990 and 19% in 2030. Age patterns would shift and reflect 92-93% of all births in developing countries by 2030. The currently high-aged population in industrialized countries would persist. The mean age in Western Europe would increase from 38 years in 1990 to 40 years and higher in 2010. These IIASA estimates give a larger world population size and a lower proportion of the elderly than the UN medium variant and the World Bank estimates.