A decline of Christian affiliation in the Western world has been observed in the decades since the end of World War II (1939–1945). While most countries in the Western world were historically almost exclusively Christian, the post–World War II era has seen developed countries with modern, secular educational facilities shifting towards post-Christian, secular, globalized, multicultural, and multifaith societies.
While Christianity is currently the predominant religion in North America, Latin America, and Europe, the religion is declining in many of these areas, particularly in Western Europe, Central Europe, the United States, Australia, Canada and New Zealand. A decline in Christianity among countries in Latin America's Southern Cone has also contributed to a rise in irreligion in Latin America.
In the Western world, historical developments since the Reformation era in the sixteenth century led to a gradual separation of church and state from the eighteenth century onward. Since at least the mid-twentieth century, there has been a gradual decline in adherence to established Christianity. In a process described as secularization, "unchurched spirituality" is gaining more prominence over organized religion.
Background
According to a 2012 Pew Research Center survey, Christianity will remain the world's largest religion throughout the next four decades. However, Christianity may experience the largest net losses in terms of religious conversion, according to expectations. Worldwide, religious conversions are projected to have a "modest impact on changes in the Christian population" between 2010 and 2050 Full report PDF and may negatively affect the growth of the Christian population and its share of the world's population "slightly".
In the past, it was believed that the rapid growth of Christianity in China during the 1980´s and 1990´s will continue and maintain, or even increase, the current numerical advantage of Christianity as the largest religion in the world. However, recent reports by Pew Research Center suggests that christianity in China has stopped growing and has instead entered a phase of stagnation. Some of the reasons for this change in course includes the crackdowns on christian churches and christian influence by Chinese authorities, the tightened oversight over clergy and congregations and the 'sinicization' of the christian faith.
In the United States, there have been some conversions to Christianity among those who grew up non-religious, but they have not been in numbers that make up for those who were raised as Christians but became religiously unaffiliated later in their lives. Full report PDF According to a Pew study in 2020, among adults aged 18 to 54 in 117 countries, 83% of those who were raised Christian remain Christian. The remaining 17% now identify as non-Christian, and the vast majority of former Christians no longer identify with any religion.
Scholars have proposed that church institutions decline in power and prominence in most industrialized societies, except in cases in which religion serves some function in society beyond merely regulating the relationship between individuals and God. Developing countries in Africa and Southeast Asia are not experiencing a decline, mostly because of religious conversion in those countries where the church offers broad social support services. Together with the decline of Western Christians, increasing numbers of Christians in the Global South will form a "new Christendom" in which the majority of the world's Christian population will be found in the South. According to various scholars and sources, Pentecostalism – a Protestant Christian movement – is the fastest-growing religion in the world; this growth is primarily due to religious conversion.
The European Values Study found that in most European countries in 2008, the majority of young respondents identified themselves as Christians. Unlike Western Europe, in Central and Eastern European countries, the proportion of Christians has either been stable or it has increased in the post-communist era. A large majority (83%) of those who were raised as Christians in Western Europe still identify as such. The remainder mostly self-identify as religiously unaffiliated. Christianity is still the largest religion in Western Europe, where 71% of Western Europeans identified themselves as Christian, according to a 2018 study by the Pew Research Center.
A 2015 analysis of the European Values Study in the Handbook of Children and Youth Studies identified a "dramatic decline" in religious affiliation across Europe from 1981 to 2008; however, according to the same analysis, "the majority of young respondents in Europe claimed that they belonged to a Christian denomination".
In 2017, a report which was released by St. Mary's University, London, concluded that Christianity "as a norm" was gone for at least the foreseeable future. In at least 12 out of the 29 European countries which were surveyed by the researchers, based on a sample of 629 people, the majority of young adults reported that they were not religious. The data was obtained from two questions, one asking, "Do you consider yourself as belonging to any particular religion or denomination?" to the full sample and the other one asking "Which one?" to the sample who replied with "Yes". The Pew Research Center criticized the methodology of the two-step approach: "Presumably, this is because some respondents who are relatively low in religious practice or belief would answer the first question by saying that they have no religion, while the same respondents would identify as Christian, Muslim, Jewish, etc., if presented with a list of religions and asked to choose among them. The impact of these differences in question wording and format may vary considerably from country to country".
In 2018, the Pope lamented the ongoing trend of repurposing churches: some of them were being used as pizza joints, skating parks, strip clubs and bars. In Germany, 500 Catholic churches have closed since 2000. Canada has lost 20% of its churches in this time frame. This is the result of a lack of clergy who are willing to staff churches as well as the result of the churches' inability to meet costs. After a scandal in Naples where a deconsecrated church became the venue for a Halloween party which featured scantily clad witches who were seated on the former altar, Pope Francis, acknowledging the decline in Church attendance, implored that the deconsecrated churches be placed in service to fulfill the social needs of caring for the poor.
In a new study published in 2022, Pew Research Center projects that if the rate of switching continues to accelerate (primarily to no religious affiliation), Christians will make up less than half of the American population by 2070, with estimated ranges for that year falling between 35% and 46% of the American population (down from 64% in 2022 and down from 91% in 1976). The same study found a retention rate among American Christians closer to 67%, with one-third of those who were Christian in childhood leaving the religion by age 30. As of 2024, Christianity's decline in the United States may have leveled off or slowed, according to the Pew Research Center and Gallup. In 2024, about 73% of Americans raised Christian still identify as Christian, while 27% are no longer Christian. Most former Christians describe themselves religiously as atheists, agnostics or nothing in particular.
Countervailing trends After years of steep decline, Christian affiliation has leveled off in some parts of the Western world. In the United States, for example, studies reports that since around 2020 the share of adults identifying as Christian has steadied at roughly 62 percent. The reversal can be observed mainly among ages 18-24: the proportion who are Crhistian climbed from 45 percent to 51 percent between 2023 and 2024, while the proportion of religiously unaffiliated "nones" slipped from 46 percent to 41 percent. A similar pattern can be seen among Generation Z—particularly young men—to some extent in Australia, Austria, Canada, Denmark, France, Ireland, New Zealand, Spain, Sweden, and the United Kingdom.
Reports also note that young men are converting in notable numbers to what they see as more "masculine expressions" of Christianity, such as the Eastern and Oriental Orthodox churches, confessional branches of Evangelical Lutheranism and Catholicism. While exact figures are difficult to verify, Pew Research Center data indicate that the Orthodox Christian population is now about 64% male, up from 46% in 2007, suggesting a marked demographic shift toward men within these communities. Congregations of Conservative Anabaptist denominations have experienced continued growth, with Conservative Anabaptists having "large families and high retention rates".
In Western countries with large enough Christian samples to analyze, most people who currently identify as Christian were also raised Christian. However, in other regions, a significant share of those who call themselves Christian were not brought up in the faith. Notably, in countries such as Singapore, South Korea, and Sri Lanka, Christian accession rates exceed 10%. In Singapore in particular, nearly half of Christians (47%) say they were raised outside of Christianity.
Europe
According to scholars, in 2017, Europe's population was 77.8% Christian (up from 74.9% in 1970). These changes were largely the result of the collapse of Communism and conversions to Christianity in the former Soviet Union and Eastern Bloc countries. According to the 2021 Eurobarometer survey, Christianity was the largest religion in the European Union, accounting for 66.1% of the EU population, down from 72% in 2012.
In 2017, Pew Research Center found that the number of Christians in Europe is in decline. This is mainly because the number of deaths is estimated to exceed the number of births among European Christians, in addition to lower fertility rates and switching to no religious affiliation.
In 2018, Pew Research Center found a retention rate among Western European Christians of around 83% (ranging from 57% in the Netherlands to 91% in Austria). Despite the decline in Christian affiliation in Western Europe, Christianity is still the largest religion in Western Europe, where 71% of Western Europeans identified themselves as Christian, according to a 2018 study by the Pew Research Center. Unlike Western Europe, in Central and Eastern European countries the proportion of Christians has been stable or even increased in the post-communist era.
In Western Europe, Christians have relatively low retention rates in the Netherlands (57%), Norway (62%), Belgium and Sweden (65%); the majority of those who have left Christianity in these countries now identify as religiously unaffiliated. Meanwhile, Christians have relatively high retention rates in Austria (91%), Switzerland and Italy (90%), and Ireland and the United Kingdom (89%). The proportion of respondents who currently identify as Christian has been in decline in Czechia and Slovakia; meanwhile, the proportion of respondents who currently identify as Christian has been stable or even increased in Eastern European countries after the collapse of Communism.
Austria
In Austria, between 1971 and 2021, Christianity declined from 93.8% to 68.2% (Catholicism from 87.4% to 55.2% and Protestantism from 6% to 3.8%) while people with no religion rose from 4.3% to 22.4%. According to the 2021 national survey conducted by Statistics Austria, among Christians, 80.9% were Catholics, 7.2% were Orthodox Christians, 5.6% were Protestants, while remaining 6.2% were Christians, belonging to other denominations of the religion or not affiliated with any denomination, and 22.4% declared they did not belong to any religion, denomination or religious community.