The New Geography of religion: how the world is becoming less Christian and more secular

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A report by the Pew Research Center, released in June 2025, reveals significant transformations in the global religious landscape over the decade between 2010 and 2020. Although virtually all religious groups grew in absolute numbers, their proportion within the global population shifted considerably, revealing a world that is less Christian, more Muslim, and increasingly secular.

Relative decline of Christianity and growth of Islam

Despite still being the world’s largest religious group (2.3 billion people), Christians declined from 30.6% to 28.8% of the global population. This percentage drop is linked both to the faster growth of other religions and to rising religious disaffiliation, especially in the West.

The number of countries with a Christian majority fell from 124 to 120, while Sub-Saharan Africa surpassed Europe as the leading Christian region, concentrating 30.7% of the world’s Christians. This reflects both Africa’s population growth and the decline of institutional Christianity in the Americas and Europe.

Muslims were the fastest-growing group during the decade, increasing by 347 million to reach 25.6% of the global population. This growth is explained by demographic factors such as high fertility rates and a young population base — 33% of Muslims are under 15 years old. Islam is now firmly established as the world’s second-largest religion, with strong growth projections for the future.

The Rise of the Religiously Unaffiliated (“Nones”)

The “nones”, people who identify as having no religious affiliation, grew by 270 million, reaching a total of 1.9 billion people in 2020 (24.2% of the global population). They are now the third-largest global group, behind only Christians and Muslims. They already form the majority in 10 countries, including:

• China (90%)

• Japan (57%)

• The Netherlands, New Zealand, Uruguay, among others

Growth in the share of nones was notable in 35 countries, including:

• United States: +13 percentage points

• Chile and Australia: +17 points

• Uruguay: +16 points

Although the nones tend to have an older demographic profile and low fertility rates, their growth is primarily driven by disaffiliation, particularly among former Christians.

Religion and Human Development Index (HDI)

There is a clear correlation between human development and lower levels of religiosity:

• Countries with high HDI tend to be more secular, urbanized, and have greater access to education and healthcare.

• Countries with low HDI, especially in Sub-Saharan Africa and South Asia, maintain high levels of religious affiliation.

This dynamic supports the rise of secularism in developed societies, where institutional religion is losing its central role.

Different religious groups show distinct age structures:

• Muslims: youngest group (33% under 15 years old)

• Jews and Buddhists: oldest groups (36% aged 50 or older)

• Christians: median age of 30.8 (close to global average)

• Religiously unaffiliated: older profile, strongly influenced by demographics in China and Japan

These age profiles directly affect growth prospects, particularly favoring younger groups such as Muslims.

Geographic Distribution

About 80% of the global population lives in countries where their religion is the majority:

• Hindus: 97% live in India and Nepal

• Christians and Muslims: widely distributed in countries where they are the majority

• Buddhists and Jews: more dispersed; often live as religious minorities

Israel is the only country with a Jewish majority, while Taiwan is the only one where “other religions” (such as Taoism and folk religions) are the majority.

China: Methodological Revision and Global Impacts

At Wong Tai Sin Temple in Hong Kong, hopeful Taoist devotees light incense sticks for good luck. Photo: Mark Leong

China plays a central role in the global religious redistribution, primarily due to the size of its population. In 2020, 90% of Chinese people (1.3 billion individuals) were classified as “religiously unaffiliated,” representing more than two-thirds of the world’s “nones.”

The Pew Research Center adopted a new criterion to measure religiosity in China. Previously, it used a combination of belief, practice, and religious identity. Now, the focus is solely on formal identity (zongjiao), what the respondent answers when directly asked about their religion, based on officially recognized institutional affiliation.

With this change:

• The estimate of the “religiously unaffiliated” jumped from 52% to 87% in 2010.

• In 2020, only 10% of Chinese people were considered formally religious—the lowest rate among all countries in the study.

This revision had a significant global impact:

• It increased the number of “nones” worldwide, consolidating them as the third largest group.

• It artificially reduced the number of Christians and Buddhists, as many Chinese practice elements of these traditions without formally identifying with a religion.

The new methodology improves comparability across countries but also underestimates the cultural and spiritual role of Chinese religious practices—such as Confucianism, popular Taoism, and ritual Buddhism. In practice, China may appear statistically secular but maintains a rich ecosystem of non-institutional beliefs and practices.

Conclusion: Long-Term Religious Trends

The world is moving toward a new religious configuration:

• Less Christian, due to disaffiliation and population aging.

• More Muslim, due to organic growth, youth, and fertility.

• More secular, with the rise of “nones” in developed countries.

These transformations have implications that go beyond individual faith. They affect collective identity, public policy, international relations, culture, and geopolitics. Religion is no longer the sole source of morality and belonging, yet it remains one of the major shaping forces of the contemporary world.

Access the full study: https://pewrsr.ch/4jA91LR

References

Hackett, Conrad, Marcin Stonawski, Yunping Tong, Stephanie Kramer, Anne Shi and Dalia Fahmy. 2025. “How the Global Religious Landscape Changed From 2010 to 2020.” Pew Research Center. doi: 10.58094/fj71-ny11.