By Verghese V Joseph –
As the world’s largest religious group, Christians had the most births and deaths of any group between 2010 and 2015. During this five-year period, an estimated 223 million babies were born to Christian mothers and roughly 107 million Christians died, meaning that the natural increase in the Christian population – i.e., the number of births minus the number of deaths – was 116 million over this period.
These are among the key findings of a new Pew Research Center analysis of demographic data. This analysis is based on – and builds on – the same database of more than 2,500 censuses, surveys and population registers used for the 2015 report “The Future of World Religions: Population Growth Projections, 2010-2050.”
Muslims had the second-largest number of births between 2010 and 2015, with 213 million babies born to Muslim mothers. But Muslims saw the largest natural increase of any religious group – more than 152 million people – due to the relatively small number of Muslim deaths (61 million). This large natural increase results from both high Muslim fertility and the concentration of the Muslim population in younger age groups, which have lower mortality rates.
Compared with the overall size of the religiously unaffiliated population (16% of the world’s people), there were relatively few recent births to unaffiliated mothers (10% of all births between 2010 and 2015). Religious “nones” are the third-largest group overall, and yet due to lower levels of fertility, they rank fourth behind Hindus in terms of babies born. Between 2010 and 2015, an estimated 68 million babies were born to unaffiliated mothers, compared with 109 million to Hindu mothers. Hindus also saw a much larger natural increase than the religiously unaffiliated (67 million vs. 26 million).
World Population to Touch 9.6 Bn
Christians were the largest religious group in the world in 2015, making up nearly a third (31%) of Earth’s 7.3 billion people. Muslims were second, with 1.8 billion people, or 24% of the global population, followed by religious “nones” (16%), Hindus (15%) and Buddhists (7%). Adherents of folk religions, Jews and members of other religions make up smaller shares of the world’s people.
Between 2015 and 2060, the world’s population is expected to increase by 32%, to 9.6 billion. Over that same period, the number of Muslims – the major religious group with the youngest population and the highest fertility – is projected to increase by 70%. The number of Christians is projected to rise by 34%, slightly faster than the global population overall yet far more slowly than Muslims.
As a result, according to Pew Research Center projections, by 2060, the count of Muslims (3.0 billion, or 31% of the population) will near the Christian count (3.1 billion, or 32%).3
Except for Muslims and Christians, all major world religions are projected to make up a smaller percentage of the global population in 2060 than they did in 2015.4 While Hindus, Jews and adherents of folk religions are expected to grow in absolute numbers in the coming decades, none of these groups will keep pace with global population growth.
Worldwide, the number of Hindus is projected to rise by 27%, from 1.1 billion to 1.4 billion, lagging slightly behind the pace of overall population growth. Jews, the smallest religious group for which separate projections were made, are expected to grow by 15%, from 14.3 million in 2015 to 16.4 million worldwide in 2060.5 And adherents of various folk religions – including African traditional religions, Chinese folk religions, Native American religions and Australian aboriginal religions, among others – are projected to increase by 5%, from 418 million to 441 million.
Buddhists, meanwhile, are projected to decline in absolute number, dropping 7% from nearly 500 million in 2015 to 462 million in 2060. Low fertility rates and aging populations in countries such as China, Thailand and Japan are the main demographic reasons for the expected shrinkage in the Buddhist population in the years ahead.
All other religions combined – an umbrella category that includes Baha’is, Jains, Sikhs, Taoists and many smaller faiths – also are projected to decrease slightly in number, from a total of approximately 59.7 million in 2015 to 59.4 million in 2060.
Major Factors: Age and Fertility
The current age distribution of each religious group is an important determinant of demographic growth. Some groups’ adherents are predominantly young, with their prime childbearing years still ahead, while members of other groups are older and largely past their childbearing years. The median ages of Muslims (24 years) and Hindus (27) are younger than the median age of the world’s overall population (30), while the median age of Christians (30) matches the global median. All the other groups are older than the global median, which is part of the reason why they are expected to fall behind the pace of global population growth.8
Moreover, Muslims have the highest fertility rate of any religious group – an average of 2.9 children per woman, well above replacement level (2.1), the minimum typically needed to maintain a stable population.9 Christians are second, at 2.6 children per woman. Hindu and Jewish fertility (2.3 each) are both just below the global average of 2.4 children per woman. All other groups have fertility levels too low to sustain their populations.
Religious Switching
In addition to fertility rates and age distributions, religious switching is likely to play a role in the changing sizes of religious groups.
Pew Research Center projections attempt to incorporate patterns of religious switching in 70 countries where surveys provide information on the number of people who say they no longer belong to the religious group in which they were raised. In the projection model, all directions of switching are possible, and they may partially offset one another. In the United States, for example, surveys find that although it is particularly common for people who grew up as Christians to become unaffiliated, some people who were raised with no religious affiliation also have switched to become Christians. These types of patterns are projected to continue as future generations come of age.
Between 2015 and 2020, Christians are projected to experience the largest losses due to switching. Globally, about 5 million people are expected to become Christians in this five-year period, while 13 million are expected to leave Christianity, with most of these departures joining the ranks of the religiously unaffiliated.
The unaffiliated are projected to add 12 million and lose 4.6 million via switching, for a net gain of 7.6 million between 2015 and 2020. The projected net changes due to switching for other religious groups are smaller.