Islam Expands, Christianity Contracts in Global Population, Survey

A recent report from the Pew Research Center, analyzing over 2,700 censuses and surveys from 2010 to 2020, reveals significant shifts in global religious demographics. While Christianity remains the world's largest religious group, its growth has not kept pace with the overall global population increase. Conversely, Islam has solidified its position as the fastest-growing major religion, and the number of religiously unaffiliated individuals has also expanded.

At the close of 2020, the Christian population stood at 2.3 billion. However, its share of the world's population declined by 1.8 percentage points, settling at 28.8%. This decrease is largely attributed to religious disaffiliation, or "switching," where individuals raised Christian choose to leave the religion. In contrast, the global Muslim population increased its share by 1.8 percentage points, reaching 25.6%.

According to Conrad Hackett, lead author of the Pew report, this decade witnessed a "dramatic change" in religious composition, bringing the Muslim and Christian populations closer in size. The rapid growth of Islam is primarily driven by a younger demographic, with an average age of approximately 24 compared to a global non-Muslim average of about 33 in 2020. Higher fertility rates in some regions and lower rates of disaffiliation among Muslims further contribute to this trend. Hackett notes that for every person who converts to Christianity among young adults globally, three individuals raised Christian depart the faith.

A notable geographical shift for Christianity is the rise of sub-Saharan Africa as home to the largest proportion of Christians, accounting for about 31% of the global Christian population. This surpasses Europe, which historically held the largest number of Christians, due to high fertility and youthful populations in sub-Saharan Africa, coupled with aging populations, lower fertility, and disaffiliation in Europe.

The rise of the religiously unaffiliated population is also a significant finding. This group, sometimes referred to as "nones," grew to 24.2% of the world's population in 2020, up from 23.3% in 2010. This increase defies previous predictions of a shrinking unaffiliated population, largely due to individuals leaving organized religion, particularly Christianity. China holds the largest unaffiliated population globally (1.3 billion out of 1.4 billion), followed by the United States (101 million out of 331.5 million) and Japan (73 million out of 126.3 million). It's important to note that in China, while many may hold spiritual beliefs or practices, formal religious identification is low.

Buddhism was the only major religion to experience an absolute decline in membership, falling from 343 million in 2010 to 324 million in 2020, attributed to disaffiliation and low birth rates. Hinduism and Judaism, however, maintained their share of the world's population, growing at rates consistent with overall global population increase.

Hackett emphasizes that while "rumors of religious revival" might circulate, the comprehensive 10-year study indicates a broad trend of people moving away from religion in many parts of the world. Based on current patterns of religious switching, age demographics, and fertility rates, he anticipates a continued "movement towards convergence" between Christian and Muslim populations, with Islam poised to become the world's largest religion in the coming years if these trends persist. Pew Research Center plans further demographic projections to estimate the exact timeline for this convergence.