The report suggests, among other key findings , that the world ’ s population would increase by slightly more than one billion people over the next 13 years, reaching 8. 6 billion in 2030, and increasing further to 9. 8 billion in 2050 and 11. 2 billion by 2100. More than half of the anticipated growth in global population between now and 2050 is expected to occur in Africa .
It states that out of the additional 2. 2 billion people who may be added to the world population between 2017 and 2050, Africa will contribute 1. 3 billion while Asia is expected to be the second largest contributor by adding just 750 million people.
According to the report, much of the overall increase in population between now and 2050 is projected to occur either in high -fertility countries, mostly in Africa , or in countries with large populations .
It states that from 2017 to 2050, it is expected that half of the world ’ s population growth will be concentrated in just nine countries: India, Nigeria , Democratic Republic of the Congo , Pakistan , Ethiopia, the United Republic of Tanzania , the United States of America , Uganda and Indonesia .
Nigeria population to overtake US before 2050
The report also notes that among the 10 largest countries of the world , one is in Africa ( Nigeria ) , five are in Asia ( Bangladesh, China , India , Indonesia, and Pakistan) , two are in Latin America ( Brazil and Mexico) , one is in Northern America ( United States of America) , and one is in Europe ( Russian Federation ) .
Ten countries are expected to account collectively for more than half of the world ’ s projected population increase over the period 2017- 2050: India, Nigeria , the Democratic Republic of Congo , Pakistan , Ethiopia, the United Republic of Tanzania, the United States of America, Uganda, Indonesia and Egypt ( ordered by their expected contribution to global growth) .
Amongst these , Nigeria ’ s population , currently the seventh largest in the world , is growing the most rapidly . Consequently, the population of Nigeria is projected to surpass that of the United States shortly before 2050, at which point it would become the third largest country in the world .
In 2050, the populations in six of the 10 largest countries are expected to exceed 300 million: China, India , Indonesia , Nigeria , Pakistan, and United States of America ( in alphabetical order ) .
Populations in many parts of the world are still young
Populations in many regions are still comparatively young.
In Africa , children under age 15 account for 41 per cent of the population in 2017 and young persons aged 15 to 24 account for an additional 19 per cent .
Latin America and the Caribbean , and Asia , which have experienced greater declines in fertility , have smaller percentages of children ( 25 and 24 per cent , respectively ) but similar percentages of youth ( 17 and 16 per cent , respectively ) .
In total , these three regions are home to 1. 8 billion children and 1. 1 billion young persons in 2017.
Providing these generations of children and youth with health care , education , and employment opportunities , including in the poorest countries and groups , will be critical for the successful implementation of the 2030 Agenda for Sustainable Development.
Proportions of children in these regions are projected to decline further in the near future , while numbers and proportions in the prime working ages can be expected to grow .
Countries with relatively high ratios of working to dependent populations have the possibility of benefitting from a “ demographic dividend, ” provided that there are sufficient opportunities for productive engagement in the labour force by the expanded working -age population .
Success in this regard requires sufficient investment in the human capital of children and youth through universal access to education and health care .
In Africa , the proportion of the population aged 25- 59 is projected to continue to grow for many decades, from 35 per cent in 2017 to 45 per cent by 2090.
In Latin America and the Caribbean , the window of time for an increasing proportion of the population at working ages will be shorter , with a peak around 2030, while in Asia the proportion aged 25- 59 will peak sooner around 2020.
Fertility has declined
In recent years , fertility has declined in virtually all regions of the world .
In Africa , where fertility levels are the highest of any region , total fertility has fallen from 5. 1 births per woman in 2000-2005 to 4. 7 in 2010-2015.
Over the same period , fertility levels also fell in Asia ( from 2. 4 to 2. 2) , Latin America and the Caribbean ( from 2. 5 to 2. 1) , and Northern America ( from 2. 0 to 1. 85) . Europe has been an exception to this trend in recent years , with total fertility increasing from 1. 4 births per woman in 2000- 2005 to 1. 6 in 2010-2015. Total fertility in Oceania has changed little since 2000, at roughly 2. 4 births per woman in both 2000-2005 and 2010- 2015.
The 47 least developed countries ( LDCs) as a group continue to have a relatively high level of fertility , at 4. 3 births per woman in 2010- 2015, and rapid population growth, at 2. 4 per cent per year .
Although this rate of increase is expected to slow significantly over the next decades , the combined population of the LDCs, roughly one billion in 2017, is projected to increase by 33 per cent between 2017 and 2030, and then to reach 1. 9 billion persons in 2050.
Africa continues to experience very high rates of population growth. Between 2017 and 2050, the populations of 26 African countries are projected to reach at least double their current size.
For six African countries , the populations are projected to increase by 2100 to more than five times their current size : Angola, Burundi , Niger , Somalia, the United Republic of Tanzania and Zambia .
Fifty- one countries or areas are projected to undergo a reduction in population size between 2017 and 2050. For ten countries or areas, populations are expected to decrease by more than 15 per cent by 2050: Bulgaria , Croatia , Latvia , Lithuania, Poland , the Republic of Moldova , Romania , Serbia , Ukraine and the United States Virgin Islands.