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Here’s the Best Prediction Yet of How Christianity and Islam Will Change Worldwide by 2050

Pew Research examines influence of births vs. conversions, and how China could change everything.
Here’s the Best Prediction Yet of How Christianity and Islam Will Change Worldwide by 2050
Image: David Evers / Flickr

Christianity will gain three times more converts than any other world religion in the coming decades. Yet it will also lose 11 times more members than any other.

If fertility rates, the size of youth populations, and rates of religion switching remain the same, Christianity will still be the largest religion in the world in 2050, according to a detailed report released today by the Pew Research Center.

But Islam will be gaining fast, nearly neck-and-neck with Christianity "possibly for the first time in history," and potentially eclipsing Christianity after 2070.

The numbers are the “first formal demographic projections using data on age, fertility, mortality, migration and religious switching for multiple religious groups around the world,” said Pew.

At 2.92 billion, Christians will make up about 31.4 percent of the population—the same as they do now. Meanwhile, Muslims will shoot up from 23.3 percent of the population in 2010 to 29.7 percent in 2050.

Pew’s projections aren’t as optimistic as the latest numbers from the Center for the Study of Global Christianity (CSGC) at Gordon-Conwell Theological Seminary, which predicts more than 3.3 billion people, or 36 percent of the world’s population, will be Christians in 2050. (Mid-2015, CSGC counts 33.4 percent of the world’s population as Christian.)

The numbers are higher because CSGC uses Christian informants to learn about informal movements like house churches, and anticipates “more non-traditional growth not picked up by censuses and surveys” than Pew does, CSGC director Todd Johnson told CT.

Since there is a lack of reliable data in China and India regarding conversions, Pew doesn’t include it, CSGC stated. But that doesn’t mean the conversions aren’t happening.

“On-the-ground contacts in China and India consistently report that Christianity is growing due to conversions, and many of these Christians are organized in ‘underground’ or secret communities,” CSGC said. That explains why CSGC’s projection for the number of Christians in both China and India in 2050 is 330 million, compared to Pew’s projection of 108 million.

Most future Christians will be living in Africa, according to both reports. The rate of Christianity there is expected to double, from 517 million in 2010 to 1.1 billion in 2050, according to Pew. CSGC numbers are similar, with a prediction of 1.2 billion Christians in Africa in 2050.

Sub-Saharan Africa, now home to a quarter of the world’s Christians, will hold 38 percent of them in 2050, Pew said.

But Islam is the world’s fastest-growing religion, and Pew predicts the tipping point will come in 2070. After that, if current trends hold, there will be more Muslims worldwide than Christians.

From Pew's report:

The projected growth of Muslims and Christians would be driven largely by the continued expansion of Africa’s population. Due to the heavy concentration of Christians and Muslims in this high-fertility region, both groups would increase as a percentage of the global population. Combined, the world’s two largest religious groups would make up more than two-thirds of the global population in 2100 (69%), up from 61% in 2050 and 55% in 2010.

It bears repeating, however, that many factors could alter these trajectories. For example, if a large share of China’s population were to switch to Christianity (as discussed in a sidebar), that shift alone could bolster Christianity’s current position as the world’s most populous religion. Or if disaffiliation were to become common in countries with large Muslim populations—as it is now in some countries with large Christian populations—that trend could slow or reverse the increase in Muslim numbers.

Eight countries will slip below 50 percent Christian in the next 40 years, according to Pew: Australia, the United Kingdom, Benin, France, the Republic of Macedonia, New Zealand, Bosnia-Herzegovina, and the Netherlands. That will leave 151 countries with a Christian majority.

At the same time, two countries—the Republic of Macedonia and Nigeria—will see populations that are more than 50 percent Muslim, in addition to the 49 countries that are currently 50 percent Muslim, Pew said.

Christianity’s slight growth likely won’t come from converts, but from birth rates, Pew said.

Christianity is expected to gain 40 million adherents from "religious switching" over the next 40 years, but will also lose 106 million. No other religion comes close to losing—or gaining—converts this drastically. Overall, Muslims will gain about 3 million from converts, while Buddhists will lose 2.8 million.

So which group gains from the roughly 60 million people who will leave the church? The unaffiliated.

CT has already noted the growing number of religiously unaffiliated in the United States. Their rate of conversion is strong: 61 million are expected to convert to the “nones” by 2050, according to Pew.

By 2050, the number of unaffiliated in the United States is expected to grow from 16 percent to just under 26 percent. That growth comes straight from Christianity, which is set to drop from 78 percent in 2010 to 66 percent in 2050, according to Pew.

In fact, the “nones” are poised to become the majority religion in France, New Zealand, and the Netherlands over the next four decades, Pew said.

But the location of the unaffiliated—in low birth rate countries of Europe, North America, China, and Japan—means both Pew and CSGC predict that the number of people worldwide who believe in nothing will drop by 2050.

The atheist population peaked in 1970 at about 165 million but has been dropping ever since, CSGC reported. By 2050, the numbers will have dropped to just over 125 million atheists. In fact, by 2050, the number of people classified as non-religionist (either atheist or agnostic) will drop from 19 percent in 1970 to less than 9 percent in 2050.

Pew’s percentages are slightly different, but predict the same trend. The unaffiliated will drop from 16 percent of the world’s population in 2010 to 13 percent in 2050. The reason is partly geographic, as “today’s religiously unaffiliated population ... is heavily concentrated in places with low fertility and aging populations, such as Europe, North America, China, and Japan.”

CSGC adds more good news: the growth rate of evangelicals from 2000 to 2015 was a rate of 2.13 percent, higher than that of Hinduism (1.26 percent), Islam (1.88 percent), or Christianity overall (1.32 percent).

While a little more than half the world’s population was unreached with the gospel in 1900, CSGC calculates that percentage has dropped to just under 30 percent today and should drop by another two percentage points by 2050.

Past CSGC studies have examined the surprising countries most missionaries are sent from and go to, the European country that’s less Christian than North Korea, and the cost of baptizing an American convert. CSGC researchers have also weighed in on why tallies of Christian martyrs vary so widely and whether persecution fuels church growth.

Pew Research has previously explored the increasingly numbers of Latin American Catholics converting to Protestantism, the rate at which Russians are returning to Orthodox Christianity, the world’s leaders of government destruction of religious properties, and the top 10 countries with the largest number of Christians living as minorities.

[Image courtesy of David Evers - Flickr]

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