I get a lot of emails expressing fear that Australia, or the Western world in general, will be taken over by Muslims because of a) immigration from predominantly Muslim countries, b) Muslims’ high fertility rate or c) both.

Obviously, if Muslims do breed faster then non-Muslims they will inevitably achieve a majority one day. But is it imminent? I constructed a small Excel model and put in some simple assumptions for Australia. Here they are:

1. Muslims represent 3% of the Australian population now.
2. Muslims’ natural rate of increase is 1.5%pa while that of non-Muslims is 0.5%pa.
3. Annual net immigration is equivalent to 1% of the population.
4. Muslims represent 30% of net immigration.
5. Anyone born to Muslim parents adopts their faith.
6. Nobody converts to or from Islam.

This set of assumptions produces a Muslim majority in the year 2289, at which time the total population of Australia will be 3.6 billion.

I’d be happy to receive evidence-based data to replace my crude assumptions; or to send out my little model to be played with by you or anyone else.

As an atheist myself I earnestly hope that nobody follows any religion at all by 2289, rendering this a pointless exercise. Fun, though.