The key takeaways from the report is world will have twice as many 65 aged persons as under-5s by 2050.
The next 30 years will see the population add 2 billion people to today’s 7.7 billion and reach 11 billion by the end of the century.
The report projects India will overtake China as the most populous country by around 2027.
What are the big pictures of the report?
Population Growth - The overall growth rate will continue to fall but the world population will reach 9.7 billion by 2050.
The next 30 years will add 2 billion and reach 11 billion by the end of the century.
The countries expected to show the biggest increase are India, Nigeria and Pakistan.
Fertility – The fertility rate is falling worldwide.
Globally, the average number of births per woman fell to 2.5 in 2019 from 3.2 in 1990. It is projected to fall further to 2.2 births by 2050.
Age Pyramid – In 2018, for the first time, persons aged 65 years or over worldwide outnumbered children under age five
By 2050, persons aged 65 years or over will be more than twice as many persons above 65 as children under five and will surpass number of adolescents and youth aged 15-34.
In India, children under age five still outnumber the over-65 population, who are projected to overtake the under-five group between 2025 and 2030.
By 2050, persons over age 65 will make up about one-seventh of India’s population.
By then, the 15-24 group in India (13.8%), too, will outnumber the over-65 group (13.6%).
Children under age five are projected to constitute less than 6% of India’s population in 2050, as compared to 7% globally.
Life expectancy – It will increase from 64.2 years in 1990 to 77.1 years in 2050.
However, life expectancy in poorer countries is projected to continue to lag behind.
The report said that, today, the average lifespan of a baby born in one of the least developed countries will be some 7 years shorter than one born in a developed country.
The main reasons are high child and maternal mortality rates, conflict and insecurity, and the continuing impact of the HIV epidemic.
Dwindling populations - The populations of 55 countries are projected to decrease by 1% or more between 2019 and 2050.
The main reductions are expected in Bulgaria, Latvia, Lithuania, Ukraine, and the Wallis and Futuna Islands.
This is because of sustained low levels of fertility, and, in some places, high rates of emigration.
Migration flows have become a major reason for population change in certain regions.
Bangladesh, Nepal and the Philippines are seeing the largest migratory outflows resulting from the demand for migrant workers.
Myanmar, Syria and Venezuela are the countries where the largest numbers are leaving because of insecurity or conflict.
Sex ratio - Males are projected to continue to outnumber females until the end of the century, but the gap will close.
