Which religion will be the largest by the end of the century?

Christianity has been the world’s most popular Abrahamic religion since its emergence over two thousand years ago, but it will lose its place to Islam at end of the 21st century according to the Pew Research Center.

At the beginning of the 20th century, Christianity had the largest number of followers numbering nearly 560 million while there were 200 million Muslims at the time. In 1900, Christians represented 34 percent of the global population while Muslims constituted 12 percent of all faiths across the globe. 

But that margin between Christian and Muslim populations dramatically changed throughout the 20th century in favour of Islam as it became the fastest growing religion across the world. That trend has continued into the 21st century, according to the Pew Research Center. 

By 2050, “the number of Muslims will nearly equal the number of Christians around the world,” if current population growth trends continue, Pew found in 2015. If it happens, for the first time in history, both faiths will have equal standing.

“Indeed, Muslims will grow more than twice as fast as the overall world population between 2015 and 2060 and, in the second half of this century, will likely surpass Christians as the world’s largest religious group,” said another study in 2017.  

While Muslim populations have continued to increase across the world in the modern age, interestingly, the political power of Islamic-dominated states from the Mughals to the Ottomans, which had ruled vast swathes of subcontinental Asia, Middle East, North Africa and Eastern Europe gradually weakened in the 19th century. 

Mughal power in the Subcontinent collapsed in the mid-19th century while the end of the Ottomans came after World War I in the early 20th century. 

Why?

“Around the world, each Muslim woman has an average of 2.9 children, compared with 2.2 for all other groups combined,” the Pew study said, referring to seven other non-Muslim major religious groups. 

The world’s Muslims are also the youngest population, being “seven years younger than the median age of non-Muslims,” according to the study - which means more young Muslims will replace older non-Muslims across the world. 

While migration is not a direct cause of population growth, due to political and economic volatility, many Muslims tend to migrate to non-Muslim majority states in Europe and the Americas, where they increase the share of Muslim populations. 

According to Pew’s data, by 2050, nearly 10 percent of Europe will be populated by Muslims. In the US, Muslims will amount to 2 percent of the population while it will be far less across Latin America according to forecasts. 

There is also a conversion factor, particularly in Europe and Sub Saharan countries in Africa, where Muslim net gains - which are calculated by subtracting people who left Islam from new converts to the monotheistic religion - appear to beat the number of conversions to other religions in the projected period between 2010 and 2050. 

“Meanwhile, religious switching – which is expected to hinder the growth of Christians by an estimated 72 million between 2015 and 2060 – is not expected to have a negative net impact on Muslim population growth,” the study said. 

One factor, being ‘religiously unaffiliated’ also favours Muslim growth as most of those people do not reside in Muslim countries. 

“Today’s religiously unaffiliated population, by contrast, is heavily concentrated in places with low fertility and aging populations, such as Europe, North America, China and Japan,” the Pew research underlined. 

Asian factor

Like the other Abrahamic religions of Judaism and Christianity, Islam also emerged in the Middle East, a region located in Asia. While much of the Christian population is not concentrated in Asia currently, population forecasts clearly show that the continent will host the biggest share of the Muslim population at the end of this century.

Asia has long been the engine of global population growth in the modern age. China and India, two Asian states, lead the world’s first and second biggest populations respectively. Both countries also have significant Muslim populations with whom they have an uneasy relationship. Indonesia, another Asian state, also holds the world’s biggest Muslim population. 

But Pew research shows that three decades later India will have the world’s largest Muslim population, taking over Indonesia’s lead.

The same research also indicates that India will still have a Hindu-majority by 2050. But if trends favouring Muslim population increases continue, then, in the long-run, India might also face to lose its Hindu-majority status. 

According to Pew projections, between 2015 and 2060 the Muslim population will grow 70 percent more while Christians will increase by 34 percent more and Hindus will see a 27 percent increase.