There are sure to be lots of people who read this bit of demographic news and react in a panic. (Gates of Vienna, I’m looking at you.) But there’s no reason to panic at all. RTFA and you will find that the article says that Muslims now outnumber Catholics.
But this is comparing only Granny Smith apples to every variety of orange. “Catholics” are one kind of Christian. There are Orthodox, Coptic, Anglican, and Protestant Christians as well, a fact which the Vatican well recognizes. The Vatican does not say Muslims outnumber Christians. Indeed, it’s quite clear that globally, Christians still outnumber Muslims by a ratio of about 5 to 3. And if you’re going to compare “Catholics” to some other kind of denomination, you need to compare them to other denominations within their umbrella religions. For instance, compare Catholics to Sunnis, or Hassidic Jews to Zen Buddhists.
There are just over six billion people in the world. One-third of them, two billion, are Christian of one kind or another. Of those two billion Christians, 1.13 billion are Catholics. It is generally assumed that there are 1.3 billion Muslims in the world. But it is not known how many of them are Sunnis, Shias, Sufis, or other kinds of sects within Islam.
I also know some folks who take it as axiomatic that Europe is being “Islamicized” through inter-generational growth of Muslims. The theory goes that Christian, Jewish, and secular Europeans are not having nearly as many children as Muslim Europeans are. Therefore, in a generation or so, Muslims are going to outnumber other factions. (Every person who has ever made such a suggestion to me coincidentally has held very intense Christian religious beliefs.)
I don’t think this can possibly be correct. There are about 15 million Muslims in the EU and another 20 million or so in Russia (I assume this number includes both the European and Asian states of Russia). The EU’s total population is over 490 million and its overall birth rate is just over the number necessary sustain that level of population. That means that less than 3.1% of Europeans are Muslim. Even if the Muslim population doubles every generation (and their children do not secularize), the EU would still not be majority-Muslim until the twenty-third century. This isn’t something that we have to worry about yet, if at all.
Russia is at greater demographic “risk” of becoming majority-Muslim, with its 141 million people – meaning about one in seven Russians is Muslim. But on the other hand, something less than two in seven Russians is Christian (with the majority of them being Orthodox) and the remaining four in seven are secular. What’s more, Russia’s population is in decline, as its death rate (16 per 1,000) is greater than its birth rate (10 per 1,000) and there is net emigration from Russia to other lands.
Nevertheless, we will not see, in our lifetimes, a majority Muslim Russia, much less a majority Muslim Europe or even less likely, a majority Muslim America. I might add that especially Muslims growing up in Western Europe will notice that many their peers are secular or only pay the barest amount of lip service to their religions, and are all perfectly happy and successful. This will (for the most part) have a secularizing, or at least moderating, effect on the view of such youth towards their own religion.
One thing I will note — secular people (atheists, agnostics, skeptics, and such) do not go around killing other people to make them set aside their faiths. If we want peace on this Earth, it will be found in the absence of religion, not the triumph of one religion over another.