Let's say you have 950,000 ethnic Europeans whose fertility rate is 1.3. And 50,000 immigrants move in with a fertility rate of 3.5. You'd have an overall fertility rate increase to 1.41, or almost 10 percent, entirely due to a tiny segment of the population. In fact, if 900,000 ethnic Europeans' fertility rate declined from 1.3 to 1.2, but 100,000 immigrants with that 3.5 rate moved in, you'd still have a 10 percent increase in the overall fertility rate, even though 90 percent of the population has bought a one-way ticket on the Oblivion Express.
And that's before we consider the two other factors: Islam's numbers in Europe grow through births plus continuing high immigration plus a rapidly expanding rate of conversion.
Europe is growing more Muslim every day. We can debate the speed, but not the direction.
Oblivion Express? The existence of Muslims in a society is zero-sum in the long run? I do not doubt the dangers of Islamism in the West; but the notion that the West's own values of pluralism, toleration, moderate faith and economic freedom are somehow completely helpless and unattractive up against the most unreconstructed version of theocracy seems to me to reflect a deep ambivalence about the West in the first place. Kind of like Western leaders whose lack of confidence in the ability of free people to withstand fundamentalist terror requires abandoning all core values.