Why Muslims
Are Rising Fastest and the Unaffiliated Are Shrinking as a Share of the World’s
Population
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. If current trends continue, by
2050 …
◾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 at France – will make up a
declining share of the world’s total population.
◾The global
Buddhist population will be about the same size it was in 2010, while the Hindu
and Jewish populations will be larger than they are today.
◾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 U.S. than people
who identify as Jewish on the basis of religion.
◾Four out of
every 10 Christians in the world will live in sub-Saharan Africa.
These are
among the global religious trends highlighted in new demographic projections by
the Pew Research Center. The projections take into account the current size and
geographic distribution of the world’s major religions, age differences,
fertility and mortality rates, international migration and patterns in
conversion.
Projected
Change in Global Population
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.
Islam
Growing FastestIf current demographic trends continue, however, Islam will
nearly catch up by the middle of the 21st century. 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.
Size and
Projected Growth of Major Religious Groups
Adherents
of various folk religions – including African traditional religions, Chinese
folk religions, Native American religions and Australian aboriginal religions –
are projected to increase by 11%, from 405 million to nearly 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 a
total of approximately 58 million to more than 61 million over the same
period.3
While
growing in absolute size, however, folk religions, Judaism and “other
religions” (the umbrella category considered as a whole) will not keep pace
with global population growth. Each of these groups is projected to make up a
smaller percentage of the world’s population in 2050 than it did in 2010.
Projected
Change in the Unaffiliated Population, 2010-2050
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.
As the
example of the unaffiliated shows, 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. Religions with many adherents in developing countries –
where birth rates are high, and infant mortality rates generally have been
falling – are likely to grow quickly. 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.
Total
Fertility Rate by Religion, 2010-2015
Globally,
Muslims have the highest fertility rate, an average of 3.1 children per woman –
well above replacement level (2.1), the minimum typically needed to maintain a
stable population. Christians are second, at 2.7 children per woman. Hindu
fertility (2.4) is similar to the global average (2.5). Worldwide, Jewish
fertility (2.3 children per woman) also is above replacement level. All the
other groups have fertility levels too low to sustain their populations: folk
religions (1.8 children per woman), other religions (1.7), the unaffiliated
(1.7) and Buddhists (1.6).
Age
Distribution of Religious Groups, 2010
Another
important determinant of growth is the current age distribution of each
religious group – whether its adherents are predominantly young, with their
prime childbearing years still ahead, or older and largely past their
childbearing years.
In 2010,
more than a quarter of the world’s total population (27%) was under the age of
15. But an even higher percentage of Muslims (34%) and Hindus (30%) were
younger than 15, while the share of Christians under 15 matched the global
average (27%). These bulging youth populations are among the reasons that
Muslims are projected to grow faster than the world’s overall population and
that Hindus and Christians are projected to roughly keep pace with worldwide
population growth.
All the
remaining groups have smaller-than-average youth populations, and many of them
have disproportionately large numbers of adherents over the age of 59. For
example, 11% of the world’s population was at least 60 years old in 2010. But
fully 20% of Jews around the world are 60 or older, as are 15% of Buddhists,
14% of Christians, 14% of adherents of other religions (taken as a whole), 13%
of the unaffiliated and 11% of adherents of folk religions. By contrast, just
7% of Muslims and 8% of Hindus are in this oldest age category.
Projected
Cumulative Change Due to Religious Switching, 2010-2050
In addition
to fertility rates and age distributions, religious switching is likely to play
a role in the growth of religious groups. But conversion patterns are complex
and varied. In some countries, it is fairly common for adults to leave their
childhood religion and switch to another faith. In others, changes in religious
identity are rare, legally cumbersome or even illegal.
The Pew
Research Center projections attempt to incorporate patterns in 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 be partially offsetting. In the United States, for example, surveys
find that some people who were raised with no religious affiliation have
switched to become Christians, while some who grew up as Christians have
switched to become unaffiliated. These types of patterns are projected to
continue as future generations come of age. (For more details on how and where
switching was modeled, see the Methodology. For alternative growth scenarios
involving either switching in additional countries or no switching at all, see
Chapter 1.)
Over the
coming decades, Christians are expected to experience the largest net losses
from switching. Globally, about 40 million people are projected to switch into
Christianity, while 106 million are projected to leave, with most joining the
ranks of the religiously unaffiliated. (See chart above.)
Impact of
Migration on Population Projections, by RegionAll told, the unaffiliated are
expected to add 97 million people and lose 36 million via switching, for a net
gain of 61 million by 2050. Modest net gains through switching also are
expected for Muslims (3 million), adherents of folk religions (3 million) and
members of other religions (2 million). Jews are expected to experience a net
loss of about 300,000 people due to switching, while Buddhists are expected to
lose nearly 3 million.
International
migration is another factor that will influence the projected size of religious
groups in various regions and countries.
Forecasting
future migration patterns is difficult, because migration is often linked to
government policies and international events that can change quickly. For this
reason, many population projections do not include migration in their models.
But working with researchers at the International Institute for Applied Systems
Analysis in Laxenburg, Austria, the Pew Research Center has developed an
innovative way of using data on past migration patterns to estimate the
religious composition of migrant flows in the decades ahead. (For details on
how the projections were made, see Chapter 1.)
The impact
of migration can be seen in the examples shown in the graph at the right, which
compares projection scenarios with and without migration in the regions where it
will have the greatest impact. In Europe, for instance, the Muslim share of the
population is expected to increase from 5.9% in 2010 to 10.2% in 2050 when
migration is taken into account along with other demographic factors that are
driving population change, such as fertility rates and age. Without migration,
the Muslim share of Europe’s population in 2050 is projected to be nearly two
percentage points lower (8.4%). In North America, the Hindu share of the
population is expected to nearly double in the decades ahead, from 0.7% in 2010
to 1.3% in 2050, when migration is included in the projection models. Without
migration, the Hindu share of the region’s population would remain about the
same (0.8%).
In the
Middle East and North Africa, the continued migration of Christians into the
six Gulf Cooperation Council (GCC) countries (Bahrain, Kuwait, Oman, Qatar,
Saudi Arabia and the United Arab Emirates) is expected to offset the exodus of
Christians from other countries in the region.7 If migration were not factored
into the 2050 projections, the estimated Christian share of the region’s
population would drop below 3%. With migration factored in, however, the
estimated Christian share is expected to be just above 3% (down from nearly 4%
in 2010).
Beyond the
Year 2050
Long-Term
Projections of Christian and Muslim Shares of World’s Population
This report
describes how the global religious landscape would change if current
demographic trends continue. With each passing year, however, there is a chance
that unforeseen events – war, famine, disease, technological innovation,
political upheaval, etc. – will alter the size of one religious group or
another. Owing to the difficulty of peering more than a few decades into the
future, the projections stop at 2050.
Readers may
wonder, though, what would happen to the population trajectories highlighted in
this report if they were projected into the second half of this century. 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?
The answer
depends on continuation of the trends described in Chapter 1. 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, 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%).
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.
It bears
repeating, however, that many factors could alter these trajectories. For
example, if a large share of China’s population were to switch to Christianity
(as discussed in this sidebar), 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.
Projected
Annual Growth Rate of Country Populations, 2010-2050
Regional
and Country-Level Projections
In addition
to making projections at the global level, this report projects religious
change in 198 countries and territories with at least 100,000 people as of
2010, covering 99.9% of the world’s population. Population estimates for an
additional 36 countries and territories are included in regional and global
totals throughout the report. The report also divides the world into six major
regions and looks at how each region’s religious composition is likely to
change from 2010 to 2050, assuming that current patterns in migration and other
demographic trends continue.8
Due largely
to high fertility, sub-Saharan Africa is projected to experience the fastest
overall growth, rising from 12% of the world’s population in 2010 to about 20%
in 2050. The Middle East-North Africa region also is expected to grow faster
than the world as a whole, edging up from 5% of the global population in 2010
to 6% in 2050. Ongoing growth in both regions will fuel global increases in the
Muslim population. In addition, sub-Saharan Africa’s Christian population is
expected to double, from 517 million in 2010 to 1.1 billion in 2050. The share
of the world’s Christians living in sub-Saharan Africa will rise from 24% in
2010 to 38% in 2050.
Meanwhile,
the Asia-Pacific region is expected to have a declining share of the world’s
population (53% in 2050, compared with 59% in 2010). This will be reflected in
the slower growth of religions heavily concentrated in the region, including
Buddhism and Chinese folk religions, as well as slower growth of Asia’s large
unaffiliated population. One exception is Hindus, who are overwhelmingly
concentrated in India, where the population is younger and fertility rates are
higher than in China or Japan. As previously mentioned, Hindus are projected to
roughly keep pace with global population growth. India’s large Muslim
population also is poised for rapid growth. Although India will continue to
have a Hindu majority, by 2050 it is projected to have the world’s largest
Muslim population, surpassing Indonesia.
The
remaining geographic regions also will contain declining shares of the world’s
population: Europe is projected to go from 11% to 8%, Latin American and the
Caribbean from 9% to 8%, and North America from 5% to a little less than 5%.
Europe is
the only region where the total population is projected to decline. Europe’s
Christian population is expected to shrink by about 100 million people in the
coming decades, dropping from 553 million to 454 million. While Christians will
remain the largest religious group in Europe, they are projected to drop from
three-quarters of the population to less than two-thirds. By 2050, nearly a
quarter of Europeans (23%) are expected to have no religious affiliation, and
Muslims will make up about 10% of the region’s population, up from 5.9% in
2010. Over the same period, the number of Hindus in Europe is expected to
roughly double, from a little under 1.4 million (0.2% of Europe’s population)
to nearly 2.7 million (o.4%), mainly as a result of immigration. Buddhists
appear headed for similarly rapid growth in Europe – a projected rise from 1.4
million to 2.5 million.
Religious
Composition of the United States, 2010-2050In North America, Muslims and
followers of “other religions” are the fastest-growing religious groups. In the
United States, for example, the share of the population that belongs to other
religions is projected to more than double – albeit from a very small base –
rising from 0.6% to 1.5%.9 Christians are projected to decline from 78% of the
U.S. population in 2010 to 66% in 2050, while the unaffiliated are expected to
rise from 16% to 26%. And by the middle of the 21st century, the United States
is likely to have more Muslims (2.1% of the population) than people who
identify with the Jewish faith (1.4%).10
In Latin
America and the Caribbean, Christians will remain the largest religious group,
making up 89% of the population in 2050, down slightly from 90% in 2010. Latin
America’s religiously unaffiliated population is projected to grow both in
absolute number and percentage terms, rising from about 45 million people (8%)
in 2010 to 65 million (9%) in 2050.11
Changing
Religious Majorities
Several
countries are projected to have a different religious majority in 2050 than
they did in 2010. The number of countries with Christian majorities is expected
to decline from 159 to 151, as Christians are projected to drop below 50% of
the population in Australia, Benin, Bosnia-Herzegovina, France, the
Netherlands, New Zealand, the Republic of Macedonia and the United Kingdom.
Countries
That Will No Longer Have a Christian Majority in 2050
Muslims in
2050 are expected to make up more than 50% of the population in 51 countries,
two more than in 2010, as both the Republic of Macedonia and Nigeria are
projected to gain Muslim majorities. But Nigeria also will continue to have a
very large Christian population. Indeed, Nigeria is projected to have the
third-largest Christian population in the world by 2050, after the United
States and Brazil.
As of 2050,
the largest religious group in France, New Zealand and the Netherlands is
expected to be the unaffiliated.
About These
Projections
While many
people have offered predictions about the future of religion, these are the
first formal demographic projections using data on age, fertility, mortality,
migration and religious switching for multiple religious groups around the
world. Demographers at the Pew Research Center in Washington, D.C., and the International
Institute for Applied Systems Analysis (IIASA) in Laxenburg, Austria, gathered
the input data from more than 2,500 censuses, surveys and population registers,
an effort that has taken six years and will continue.
The
projections cover eight major groups: Buddhists, Christians, Hindus, Jews,
Muslims, adherents of folk religions, adherents of other religions and the
unaffiliated (see Appendix C: Defining the Religious Groups). Because censuses
and surveys in many countries do not provide information on religious subgroups
– such as Sunni and Shia Muslims or Catholic, Protestant and Orthodox
Christians – the projections are for each religious group as a whole. Data on
subgroups of the unaffiliated are also unavailable in many countries. As a result,
separate projections are not possible for atheists or agnostics.
The
projection model was developed in collaboration with researchers in the Age and
Cohort Change Project at IIASA, who are world leaders in population projections
methodology. The model uses an advanced version of the cohort-component method
typically employed by demographers to forecast population growth. It starts
with a population of baseline age groups, or cohorts, divided by sex and
religion. Each cohort is projected into the future by adding likely gains
(immigrants and people switching in) and by subtracting likely losses (deaths,
emigrants and people switching out) year by year. The youngest cohorts, ages
0-4, are created by applying age-specific fertility rates to each female cohort
in the childbearing years (ages 15-49), with children inheriting the mother’s
religion. For more details, see the Methodology.12
In the
process of gathering input data and developing the projection model, the Pew
Research Center previously published reports on the current size and geographic
distribution of major religious groups, including Muslims (2009), Christians
(2011) and several other faiths (2012). An initial set of projections for one
religious group, Muslims, was published in 2011, although it did not attempt to
take religious switching into account.
Some social
theorists have suggested that as countries develop economically, more of their
inhabitants will move away from religious affiliation. While that has been the
general experience in some parts of the world, notably Europe, it is not yet
clear whether it is a universal pattern.13 In any case, the projections in this
report are not based on theories about economic development leading to
secularization.
Rather, the
projections extend the recently observed patterns of religious switching in all
countries for which sufficient data are available (70 countries in all). In
addition, the projections reflect the United Nations’ expectation that in
countries with high fertility rates, those rates gradually will decline in
coming decades, alongside rising female educational attainment. And the
projections assume that people gradually are living longer in most countries.
These and other key input data and assumptions are explained in detail in
Chapter 1 and the Methodology (Appendix A).
Since
religious change has never previously been projected on this scale, some
cautionary words are in order. Population projections are estimates built on
current population data and assumptions about demographic trends, such as
declining birth rates and rising life expectancies in particular countries. The
projections are what will occur if the current data are accurate and current
trends continue. But many events – scientific discoveries, armed conflicts,
social movements, political upheavals, natural disasters and changing economic
conditions, to name just a few – can shift demographic trends in unforeseen
ways. That is why the projections are limited to a 40-year time frame, and
subsequent chapters of this report try to give a sense of how much difference
it could make if key assumptions were different.
For
example, China’s 1.3 billion people (as of 2010) loom very large in global
trends. At present, about 5% of China’s population is estimated to be
Christian, and more than 50% is religiously unaffiliated. Because reliable
figures on religious switching in China are not available, the projections do
not contain any forecast for conversions in the world’s most populous country.
But if Christianity expands in China in the decades to come – as some experts
predict – then by 2050, the global numbers of Christians may be higher than
projected, and the decline in the percentage of the world’s population that is
religiously unaffiliated may be even sharper. (For more details on the possible
impact of religious switching in China, see Chapter 1.)
Finally,
readers should bear in mind that within every major religious group, there is a
spectrum of belief and practice. The projections are based on the number of
people who self-identify with each religious group, regardless of their level
of observance. What it means to be Christian, Muslim, Hindu, Buddhist, Jewish
or a member of any other faith may vary from person to person, country to
country, and decade to decade.
Acknowledgements
These
population projections were produced by the Pew Research Center as part of the
Pew-Templeton Global Religious Futures project, which analyzes religious change
and its impact on societies around the world. Funding for the Global Religious
Futures project comes from The Pew Charitable Trusts and the John Templeton
Foundation.
Many staff
members in the Pew Research Center’s Religion & Public Life project
contributed to this effort. Conrad Hackett was the lead researcher and primary
author of this report. Alan Cooperman served as lead editor. Anne Shi and Juan
Carlos Esparza Ochoa made major contributions to data collection, storage and
analysis. Bill Webster created the graphics and Stacy Rosenberg and Ben Wormald
oversaw development of the interactive data presentations and the Global
Religious Futures website. Sandra Stencel, Greg Smith, Michael Lipka and
Aleksandra Sandstrom provided editorial assistance. The report was
number-checked by Shi, Esparza Ochoa, Claire Gecewicz and Angelina Theodorou.
Several researchers
in the Age and Cohort Change project of the International Institute for Applied
Systems Analysis collaborated on the projections, providing invaluable
expertise on advanced (“multistate”) population modeling and standardization of
input data. Marcin Stonawski wrote the cutting-edge software used for these
projections and led the collection and analysis of European data. Michaela
Potančoková standardized the fertility data. Vegard Skirbekk coordinated
IIASA’s research contributions. Additionally, Guy Abel at the Vienna Institute
of Demography helped construct the country-level migration flow data used in
the projections.
Over the
past six years, a number of former Pew Research Center staff members also
played critical roles in producing the population projections. Phillip Connor
prepared the migration input data, wrote descriptions of migration results and
methods, and helped write the chapters on each religious group and geographic
region. Noble Kuriakose was involved in nearly all stages of the project and
helped draft the chapter on demographic factors and the Methodology. Former
intern Joseph Naylor helped design maps, and David McClendon, another former
intern, helped research global patterns of religious switching. The original
concept for this study was developed by Luis Lugo, former director of the Pew
Research Center’s Religion & Public Life project, with assistance from
former senior researcher Brian J. Grim and visiting senior research fellow
Mehtab Karim.
Others at
the Pew Research Center who provided editorial or research guidance include
Michael Dimock, Claudia Deane, Scott Keeter, Jeffrey S. Passel and D’Vera Cohn.
Communications support was provided by Katherine Ritchey and Russ Oates.
We also
received very helpful advice and feedback on portions of this report from
Nicholas Eberstadt, Henry Wendt Scholar in Political Economy, American
Enterprise Institute; Roger Finke, Director of the Association of Religion Data
Archives and Distinguished Professor of Sociology and Religious Studies, The
Pennsylvania State University; Carl Haub, Senior Demographer, Population
Reference Bureau; Todd Johnson, Associate Professor of Global Christianity and
Director of the Center for the Study of Global Christianity, Gordon Conwell
Theological Seminary; Ariela Keysar, Associate Research Professor and Associate
Director of the Institute for the Study of Secularism in Society and Culture,
Trinity College; Chaeyoon Lim, Associate Professor of Sociology, University of
Wisconsin-Madison; Arland Thornton, Research Professor in the Population
Studies Center, University of Michigan; Jenny Trinitapoli, Assistant Professor
of Sociology, Demography and Religious Studies, The Pennsylvania State
University; David Voas, Professor of Population Studies and Acting Director of
the Institute for Social and Economic Research, University of Essex; Robert
Wuthnow, Andlinger Professor of Sociology and Director of the Center for the
Study of Religion, Princeton University; and Fenggang Yang, Professor of
Sociology and Director of the Center on Religion and Chinese Society, Purdue
University.
While the
data collection and projection methodology were guided by our consultants and
advisers, the Pew Research Center is solely responsible for the interpretation
and reporting of the data.
Roadmap to
the Report
The
remainder of this report details the projections from multiple angles. The
first chapter looks at the demographic factors that shape the projections,
including sections on fertility rates, life expectancy, age structure,
religious switching and migration. The next chapter details projections by
religious group, with separate sections on Christians, Muslims, the religiously
unaffiliated, Hindus, Buddhists, adherents of folk or traditional religions,
members of “other religions” (consolidated into a single group) and Jews. A
final chapter takes a region-by-region look at the projections, including
separate sections on Asia and the Pacific, Europe, Latin America and the
Caribbean, the Middle East and North Africa, North America and sub-Saharan
Africa. (Pew Research Center, April 2, 2015)
