Academic journal article Demographic Research

The Future Size of Religiously Affiliated and Unaffiliated Populations

Academic journal article Demographic Research

The Future Size of Religiously Affiliated and Unaffiliated Populations

Article excerpt

1. Introduction

Social scientists have a long history of predicting the demise of religion. Auguste Comte, Emile Durkheim, Sigmund Freud, and Karl Marx envisioned the decline of organized religion and the rise of the religiously unaffiliated. More recently the idea that the unaffiliated population will increase has been promoted using mathematical models of social group competition (Abrams, Yaple et al. 2011) and assumptions that growing economic development will lead to evolution away from religion (Barber 2012). But these predictions did not take demography into account - specifically, that patterns in global population growth favor those who have religious affiliation (Norris and Inglehart 2004; Kaufmann 2010). Our new demographic analysis finds that affiliated women have more children than unaffiliated women - nearly a full child more per woman, on average, worldwide. In addition, the global median age of affiliated women is six years younger than unaffiliated women, so they have more potential years of childbearing and living ahead. We project these demographic characteristics will result in a more religiously affiliated global population in coming decades. Although current patterns of religious switching favor the unaffiliated, they are insufficient at the global level to offset the demographic advantages of the affiliated.

Demographic projections of affiliated and unaffiliated populations were not possible in the past because scholars had not collected the worldwide data necessary to make them. We assembled a database of religious composition and demographic characteristics, based on more than 2,500 censuses, surveys, and population registers for 198 countries and territories that make up 99.98% of the world's population. Using this database, we made demographic projections of religiously affiliated and unaffiliated populations for the period from 2010 to 2050. Our global projections assume the continuation of recent switching patterns that strongly favor the unaffiliated, particularly in North America, Europe, and Latin America, where we project the unaffiliated will grow as a share of those regions' populations. But if current trends continue, the religiously unaffiliated will decline as a percentage of the world's overall population, from 16.4% in 2010 to 13.2% in 2050. Even when we model a 50% increase in current rates of switching, tilting even more in favor of religious disaffiliation, the unaffiliated share of the world's population would still be expected to decline, falling to 14.3% in 2050.

2. Defining the religiously affiliated and unaffiliated

The religiously unaffiliated include atheists, agnostics, and people who do not identify with any particular religion in surveys and censuses. We estimate that 1.1 billion people were religiously unaffiliated in 2010, including more than 700 million in China, home to 62% of the world's religiously unaffiliated people. Some who state "no religion" in surveys do maintain a mix of religious beliefs and practices (Hout and Fischer 2002, Baker and Smith 2009). Nonetheless, based on the absence of self-identified religious affiliation, we classify them as unaffiliated (Hackett, Grim et al. 2012).

The majority of the population in China, the Czech Republic, Estonia, Hong Kong, Japan, and North Korea are religiously unaffiliated. The unaffiliated populations in these countries are considerably older than the rest of the world's population. By contrast, in the United States, Australia, New Zealand and many European countries, unaffiliated minorities have been growing in recent years, with growth often concentrated among young adults.

The religiously affiliated include, in order of 2010 population size, Christians, Muslims, Hindus, Buddhists, people who practice folk or traditional religions, adherents of other religions, and Jews (Hackett, Grim et al. 2012). In this context, religious affiliation is measured by identification with one of these groups on a census or survey. …

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