The Pew Research Center published a comprehensive study analyzing over 2,700 censuses and surveys, indicating shifts in global religious demographics. The report reveals that although Christians remain the largest religious community worldwide, their growth lagged behind the overall growth rate of the world's population.
From 2010 to 2020, the proportion of Christians in the global population decreased by 1.8 percentage points, falling to 28.8%, despite an increase of 122 million Christians. This decline is attributed to disaffiliation and religious apostasy, particularly in Europe and America, where many are turning away from Christianity, according to The Washington Post.
During the same period, Islam solidified its position as the fastest-growing major world religion. The proportion of Muslims in the global population increased by 1.8 percentage points, rising to 25.6%. The Muslim population grew by 347 million to reach 2 billion, a surge driven by higher fertility rates, a younger average age of about 24 years, and relatively low apostasy rates in some regions.
"Islam is set to grow to become the world's largest religion in years ahead, unless trend lines shift," said Conrad Hackett, the lead researcher at the Pew Research Center, according to The Washington Post. "It's just striking that there was such dramatic change in a 10-year period," Hackett noted, emphasizing that the Muslim and Christian populations grew closer in size, with Muslims growing faster than any other major religion.
Hackett further elaborated on the factors contributing to Christianity's decline. "Among young adults, for every person around the world who becomes Christian, there are three people who are raised Christian who leave," Hackett said. The increase in the number of people with no religious affiliation is influenced by the departure from Christian churches.
The study found that the number of religiously unaffiliated individuals increased by 270 million over the past decade, reaching 1.9 billion and constituting 24.2% of the global population. Estimates suggest that the largest number of religiously unaffiliated people is in China, with 1.3 billion out of 1.4 billion people. In China, it is common for people to have religious beliefs, but only 10% of the population officially belongs to a specific denomination or religion, while 90% are religiously unaffiliated.
Japan also reports a high percentage of religiously unaffiliated individuals, with 73 million out of 126.3 million people. This trend reflects a broader global movement away from organized religion. "Sometimes we hear rumors of religious revival, and it's certainly possible that in particular places religion could grow. But in this careful 10-year study that we've done, the broad trend is that in many places people are moving away from religion," Hackett commented.
Buddhism was the only major religion to see a decline in followers, with its population decreasing by 19 million over the past decade, totaling 324 million. The decline in Buddhism is attributed to religious disaffiliation and lower birth rates.
Meanwhile, the number of Hindus and Jews remained stable with the world's population, with Hindus increasing by 126 million to 1.2 billion and Jews by 1 million to 14.8 million. Other religions like Daoism, Sikhism, or Bahá'í remained stable at 2.2%.
The report also notes a shift in the global center of gravity of Christianity. Previously, Europe was home to the largest number of Christians in the world, but now the largest Christian population is in sub-Saharan Africa. According to the study, about 31 percent of the world's Christians can be found in sub-Saharan Africa. "And that's the result of high fertility, youthfulness, and rapid growth in sub-Saharan Africa, as well as the aging, lower fertility, and disaffiliation going on in Europe," Hackett explained.
In Europe, as of 2020, the proportion of Christians fell to 67.1%, indicating a decrease of 7.6 percentage points compared to 2010. The proportion of the Muslim population in Europe increased by 0.7 percentage points, rising to 6%.
The study's findings suggest that the movement towards convergence between Christians and Muslims will continue. Based on patterns of religious disaffiliation and differences in age and fertility, Hackett estimated that this trend is likely to persist. "The next step of our ongoing work in this project will be to do some demographic population projections to provide new estimates of sort of exactly when they might converge," he said.
The new report measures self-described affiliations around the world and may not capture the nuances and completeness of complex and evolving identities. Many people hold religious or spiritual beliefs or attend worship services but avoid official labels.
Researchers previously estimated the unaffiliated population would shrink because of older age and fewer people having children. However, people leaving religion, especially departing Christianity, has led to the increase of the unaffiliated population.
Written with the help of a news-analysis system.