A new book is out on the state of the church in Canada. The picture it paints is pretty grim.

Called Leaving Chris­tianity: Changing Allegiances in Canada Since 1945, the book by professors Brian Clarke and Stuart Macdonald shows that many denominations, not just mainline ones, are in serious trouble.

According to Clarke and Macdonald, census data indicates other groups — Christian Reformed, Pentecostals, Mennonites, Salvation Army and some Baptist groups — are also seeing decreases.

Altogether, it adds up to a significant “disengagement with church-based religion,” they write.

“There is a decline in the number of people who socialize their children into churches or go to churches for rites of passage. There is a decline among those who come to church expecting that their needs for friendship and community will be met there.”

This decline, they state, will “profoundly affect how Canadians live their lives, the vitality of their religious institutions, the salience of these institutions in Canadian society and the state of Canadian civil society, in which churches and church-affiliated organizations had a significant presence.”

The authors trace the start of the decline to the 1960s, when baby boomers started to leave the church.

Many went on to become “nones” over the next several decades — people who indicate their religion on a census by selecting “none of the above.”

Some 7.8 million Canadians identify as having no religion, about 25 percent. In 1961, that figure was 1 percent.

But along with the growth in the de-churched — those who have left religion — there’s a new cohort not seen in such large numbers before: The children of the “nones.”

There are more than 1.5 million Canadians under 15 who have never been to church, except for weddings or funerals.

“As opposed to their parents who left church and became dechurched, they are among the non-churched and have very little or no exposure to Christian beliefs and practices,” the authors say.

Of course, not all denominations are struggling. Some conservative and evangelical groups are doing better.

But beginning in the 1990s, “many of them have seen decline. The end of a common Christian culture is now affecting them, as it did earlier with the country’s larger Protestant denominations.”

According to Clarke and Macdonald, there is no easy fix. The trends they are tracking are well entrenched. They recommend denominations “accept that Canada is a de-Christianized, post-Christian society. The challenge for churches is how to . . . function effectively in this context.”

It’s not a matter of tweaking the music or liturgy. It is about finding new ways to communicate about faith “in a culture that no longer understands what they are talking about. [Churches] can no longer appeal to Christian symbols and ideas that used to be diffused in the general culture.”

As churchgoers themselves, the authors hope for the best for the church. But they believe the large level of disengagement from organized Christianity in Canada is not going away.

Something similar may also be true for the U.S. There’s a school of thought that says when it comes to religiosity, Canada is 10 to 20 years behind Europe, and the U.S. is 10 to 20 years behind Canada. That may or may not be true, but one thing seems certain: We are headed to a post-Christian society. In Canada, we may already be there.

John Longhurst, of Winnipeg, Man., is director of resources and public engagement at Canadian Foodgrains Bank.