A report by the Pew Research Centre has predicted that the number of Muslims in the world will draw level with the number of Christians by 2050 and probably exceed it by 2070.
The report, entitled “The Future of World Religions: Population Growth Projections 2010-50”, says the religious profile of the world is rapidly changing, driven primarily by differences in fertility rates and the size of youth populations among the world’s major religions, as well as by people switching faiths.
Over the next four decades, Christians will remain the largest religious group, but Islam will grow faster than any other major religion.
– The number of Muslims will nearly equal the number of Christians around the world.
– Atheists, agnostics and other people who do not affiliate with any religion – though increasing in countries such as the United States and France – will make up a declining share of the world’s total population.
– In Europe, Muslims will make up 10% of the overall population.
– India will retain a Hindu majority but also will have the largest Muslim population of any country in the world, surpassing Indonesia.
– In the United States, Christians will decline from more than three-quarters of the population in 2010 to two-thirds in 2050, and Judaism will no longer be the largest non-Christian religion. Muslims will be more numerous in the US than people who identify as Jewish on the basis of religion.
Religion on the increase
As of 2010, Christianity was by far the world’s largest religion, with an estimated 2.2 billion adherents, nearly a third (31%) of all 6.9 billion people on Earth. Islam was second, with 1.6 billion adherents, or 23% of the global population.
Between 2010 and 2050, the world’s total population is expected to rise to 9.3 billion, a 35% increase.
Over that same period, Muslims – a comparatively youthful population with high fertility rates – are projected to increase by 73%. The number of Christians also is projected to rise, but more slowly, at about the same rate (35%) as the global population overall.
As a result, according to the Pew Research projections, by 2050 there will be near parity between Muslims (2.8 billion, or 30% of the population) and Christians (2.9 billion, or 31%), possibly for the first time in history.
With the exception of Buddhists, all of the world’s major religious groups are poised for at least some growth in absolute numbers in the coming decades. The global Buddhist population is expected to be fairly stable because of low fertility rates and aging populations in countries such as China, Thailand and Japan.
Worldwide, the Hindu population is projected to rise by 34%, from a little over 1 billion to nearly 1.4 billion, roughly keeping pace with overall population growth.
Jews, the smallest religious group for which separate projections were made, are expected to grow 16%, from a little less than 14 million in 2010 to 16.1 million worldwide in 2050.
Atheists and agnostics on downward trend
Similarly, the religiously unaffiliated population is projected to shrink as a percentage of the global population, even though it will increase in absolute number.
In 2010, censuses and surveys indicate, there were about 1.1 billion atheists, agnostics and people who do not identify with any particular religion. By 2050, the unaffiliated population is expected to exceed 1.2 billion.
But, as a share of all the people in the world, those with no religious affiliation are projected to decline from 16% in 2010 to 13% by the middle of this century.
At the same time, however, the unaffiliated are expected to continue to increase as a share of the population in much of Europe and North America. In the United States, for example, the unaffiliated are projected to grow from an estimated 16% of the total population (including children) in 2010 to 26% in 2050.
There will be vivid geographic differences in patterns of religious growth in the coming decades. One of the main determinants of that future growth is where each group is geographically concentrated today.
Much of the worldwide growth of Islam and Christianity, for example, is expected to take place in sub-Saharan Africa. 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.
Beyond the Year 2050
Given the rapid projected increase from 2010 to 2050 in the Muslim share of the world’s population, would Muslims eventually outnumber Christians? And, if so, when?
If the main projection model is extended beyond 2050, 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.
By the year 2100, about 1% more of the world’s population would be Muslim (35%) than Christian (34%).
The projected growth of Muslims and Christians would be driven largely by the continued expansion of Africa’s population. Due to the heavy concentration of Christians and Muslims in this high-fertility region, both groups would increase as a percentage of the global population.
Combined, the world’s two largest religious groups would make up more than two-thirds of the global population in 2100 (69%), up from 61% in 2050 and 55% in 2010.
However, according to Pew, many factors could alter these trajectories.
For example, if a large share of China’s population were to switch to Christianity, that shift alone could bolster Christianity’s current position as the world’s most populous religion.
Or if disaffiliation were to become common in countries with large Muslim populations – as it is now in some countries with large Christian populations – that trend could slow or reverse the increase in Muslim numbers.