Is Religion Fading Away?

When I moved from Colorado to British Columbia to California in the span of two years I noticed something surprising: in every place I lived the majority of people I spoke with regarding religion expressed doubt. Before I moved from Colorado I thought my small group of agnostic friends was a coincidence. But when I arrived in BC, and then California, I began to wonder if the world was less religious than I’d imagined. 

Recently I decided to find the answer to a question that has rattled around in my head for years: is religion fading away?

In the 1950s just about everyone practiced religion. However, in the last 50 years religion in America has seen a steep decline if you measure the portion of the population that practices religion. The percentage of Americans who don’t practice religion has grown from 2% in 1965 to 17% in 2015. And projections by Pew Research Center suggest the trend of religions decline will continue for the next 50 years. So it would seem the answer to my question in America is a resounding yes.

Percentage of Americans Who Don’t Practice Religion

However, looking at global trends, a different picture emerges. There are an estimated 1.1 billion people in the world that aren’t affiliated with any religion. And while that group is estimated to grow by 100 million people by 2050, the actual percentage of humans in this group will decrease from 16.4% to 13.2% according to Pew Research Center.

Christianity and Islam, on the other hand will both grow, picking up an additional 750 million and 1.1 billion people respectively. So it would seem that a more worldly answer to my question is this: while religious affiliation is on the decline in America, it is growing globally. 

Why is religion fading away in America?

There are two main causes for the decline of religion in America.

The first reason is what researchers call “generational replacement.” Put bluntly, old people that went to church are dying and young people aren’t taking their spot in the pew. Someone born in the Silent Generation (between 1928-1945) is 3 times more likely to be religiously affiliated than a Millenial (between 1981-1996). 

Some people argue that Millenials will become more religious as they age. But data suggests otherwise. Pew Research Center conducted a survey in 2007 and found 25% of millenials didn’t affiliate with religion. 7 years later that number grew to 34%.

In addition to generational replacement, a trend of “religious switching”can be blamed. Nearly one-in-five (18%) US-adults were raised in a religious faith and now identify with no religion. 

Former Christians represent the largest group of converts in the United States. In fact, the number of former Christians exceeds the population of California and my home state of Colorado combined, with an estimated 47 million people.

Why is the rest of the world getting more religious?

There is no single reason why the rest of the world is becoming more religious. But the most telling data point to look at is fertility rates by religion. 

Fertility rates are a great indicator of population growth. They describe how many children a woman is likely to have in her lifetime. In countries with high fertility rates, such as Niger a woman is likely to have about 7 children; therefore the population is growing quickly. In countries with lower fertility rates, like Singapore, a woman is expected to give birth to one child in her lifetime; therefore the population is declining. 

Generally a fertility rate of 2.2 results in zero population growth. Anything above it means that the population will grow. And anything below it means the population will recede. For this reason analyzing fertility rates by religion is a great way to predict the future of religious populations. After all, religion is cultural which means that children adopt the faith of their family and surrounding community. Therefore if we want to predict how religious the world will be in 50 years it is most useful to look at population growth by country and then each country’s dominant religion.

Today most of the world’s population growth is taking place in Africa and the Middle East where Christianity and Islam are the dominant religions. Populations in North America and Europe — where skepticism is becoming increasingly popular — are growing slowly or receding. 

If you only had 60 seconds to tell someone why more of the world’s population is becoming religious this is the simplest answer.