The following study by the Pew Research Center titled “The Future of World Religions: Population Growth Projections, 2010-2050” suggest that the fastest growing religion in the world is Islam, that Christianity will remain the most followed religion for the next several decades, and that atheism and agnosticism is in decline (with the exception in the countries of the USA and France).
By 2070 Islam is expected to level out with Christianity, and will compromise of 10% of Europe’s population. Judaism will also no longer be the biggest non-Christian religion is the USA, and that title will belong to Islam.
Between 2010 and 2050 Islam is projected to increase by 73%, whilst the number of Christians also is projected to rise but at a slower pace (35%). Judaism will grow by 16%, Hinduism by 34%, Folk Religions by 11%, and Buddhism is expected to recede by 0,3%. Interestingly, while the religiously unaffiliated population (atheists, agnostics and 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, and is expected to exceed 1.2 billion, by 2050. In the USA the unaffiliated are projected to grow from an estimated 16% of the total population in 2010 to 26% in 2050.
Beyond 2015, the “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%).”
View the full study at the Pew Research Center.