Pew Research Center released a 2015 study The Future of World Religions: Population Growth Projections, 2010-2050 which sheds light on a few important trends.
The fastest growing religion worldwide is Islam, and Christianity will remain the most followed religion for the next several decades. Between 2010 and 2050 Islam is projected to increase by 73%, whilst the number of Christians is also projected to rise but at a slower pace (35%). Judaism will grow by 16%, Hinduism by 34%, and Folk Religions by 11%. Buddhism is expected to recede by 0,3%.
By 2050, India will retain a Hindu majority but also will have the largest Muslim population of any country in the world, surpassing Indonesia. In the year 2070 Islam is expected to level out with Christianity, and will comprise 10% of Europe’s population.
“Muslim share of the world’s population would equal the Christian share, at roughly 32% each, around 2070. After that, the number of Muslims would exceed the number of Christians, but both religious groups would grow, roughly in tandem, as shown in the graph above. By the year 2100, about 1% more of the world’s population would be Muslim (35%) than Christian (34%).”
Judaism will also no longer be the biggest non-Christian religion in the United States because it will be replaced by Islam. American Christians are expected to decline from more than three-quarters of the population in 2010 to two-thirds in 2050.
While the religiously unaffiliated numbers (atheists, agnostics, and those people who do not identify with any particular religion) is projected to shrink as a percentage of the global population (from 16% to 13%), it will increase in the number of followers. It is expected to exceed 1.2 billion by 2050. In the United States the unaffiliated are projected to grow from an estimated 16% of the total population in 2010 to 26% in 2050.
Atheism and agnosticism are in decline with the exception of the United States and France.
Folk Religions and Smaller Religions
Adherents of folk religions, including African traditional religions, Chinese folk religions, Native American religions and Australian aboriginal religions, are projected to increase by 11%. Their number will rise from 405 million to just shy of 450 million.
And all other religions combined – an umbrella category that includes Baha’is, Jains, Sikhs, Taoists and many smaller faiths – are projected to increase 6%, from approximately 58 million to more than 61 million over the same period.
[First published 2015. Edited 12/07/2019]