Doesn’t matter in the long term.
Islam will win on the ground, eventually. The solution, is Mutual Assured Destruction.
By the time the Muslims take over most of the rest of the world, they will have enough nukes to retaliate.
The result of World War III will be the Muslims overrunning the rest of the world, and then a full scale nuclear war, resulting in a nuclear winter and the end of Homo sapiens as a species.
If the species survives on the margins, it will never again have technology beyond middle ages, because energy-wise, the low-hanging fruit has already been picked, and you need higher tech to get to the harder to find energy.