While a new study by the Pew Research Center concludes that the religious future of China is uncertain due to data limitations, of which I've written extensively,* the Pew study offers three "sensitivity tests" looking at the effects of religious switching on the future size of the Chinese Christian population:
- "As of 2010, China had an estimated 68 million Christians and 701 million unaffiliated people. Due primarily to differences in the age and sex composition of these initial populations, in the main projection scenario – which does not attempt to model religious switching – China’s Christian population is expected to grow slightly by 2050, to 71 million, while the unaffiliated population is expected to decline to 663 million."
- "Under that main scenario, 5.4% of China’s population and 31.4% of the world’s total population will be Christian in 2050. If China’s Christian population were to decline to Japanese levels (2.4% of the country’s population) in 2050, it would reduce the Christian share of the global population to 30.9%. On the other hand, if China’s Christian population was to increase to the level projected for South Korea in 2050 (33.3% of the country’s population), it would raise the count of Christians in China to 437 million and the share of Christians in the world’s overall population to 35.3%."
- "And if everyone who is currently unaffiliated in China were to convert to Christianity by 2050, China’s population would be 56.2% Christian (734 million Christians), raising the Christian share of the world’s population to 38.5% and lowering the unaffiliated share of the global population to 6.1%. Though that scenario may be unlikely, it offers a rough sense of how much difference religious switching in China maximally could have by 2050. Extremely rapid growth of Christianity in China could maintain or, conceivably, even increase Christianity’s current numerical advantage as the world’s largest religion, and it could significantly accelerate the projected decline by 2050 in the share of the global population that is religiously unaffiliated." (Pew Research)
* The reason that the religious future in China is so difficult to estimate is due to measurement difficulties ranging from reluctance of individuals to disclose religious affiliation to pollsters to the massive internal migration that has seen well over one hundred million people move from the countryside into cities since 1980. Much of this movement - considered the largest migration in human history - is difficult to track and count, including whether the Christians who moved from the countryside have stimulated Christian growth in cities or have lost touch with their roots. Thus, there are no reliable sources to precisely measure patterns of religious conversion in China.
One thing is clear, Christianity's future in China will have a measurable impact on global Christianity. For more on China, see my recent article, What Christianly Contributes to China's Economic Rise.