score:31
The question is of course kind of entirely biased, as always when you take a statistical correlation and want to apply a cause on that. However, the question should still be answered. It just means that a definitive answer will not be obtained, only "elements". Actually, there are quite a lot of elements to explain this repartition of Islam's expansion. Some are as follows:
1/ First phase: Existing Forces
The initial development of Islam was opposed to existing forces: empires, kingdoms that were fought and often beaten by Islamic-Arabic fighters (some would say soldiers, other tribes, so I'll use the generic word "fighter"). Those wars took time and resources, so an efficient resistance triggered less expansion of Islam than a fierce resistance. So, in history, how did it take place?
2/ Second phase: Conversion
After the military conquest, the converting activities from imams and predictors were the major reason for Islam's expansion. Again, different regions led to different processes:
In this phase, note that commercial links usually gave the direction of conversion: that is why Islam mostly expanded on the coasts of the Indian Ocean (Indonesia, East coast of Africa).
3/ Containment
Now came the 16th century: by that time, the big push of Europe, especially Portugal, in Asia and Africa push Christianity as a competitor to Islam in conversion. Powered by trade and military victories, Christianity stopped the expansion of Islam at his borders in the Indian Ocean and Africa:
In East Asia, China was still a too powerful spiritual power. In Europe, Christianity was well established and blocked any expansion, except for Timurid and Golden Horde military (but temporary) expansions.
Conclusion:
Yes, Islam expansion followed a pattern directed by specific causes. No, this is not directly about climate. This is more about having established religions and military powerful "states", or not yet, at the borders of the initial Islam center. Finally: Yes, the climate has something to do with the presence, or not, of those established systems:
Upvote:1
Maybe. Specifically the Arab conquests. There are a lot of other factors that determined where they did and didn't conquer, like the strong walls of Constantinople. But I think climate might be in there somewhere.
The climate change during the "Late Antiquity Little Ice Age" weakened the Roman and Sassanid empires. At the same time, it increased fertility on the Arabian peninsula. So climate change likely was a factor in the Arab's general military success.
I'm somewhat speculating, but perhaps the southern areas of the Roman (and ex-Roman) world and the Iranian Plateau were the places most weakened by this change. If so, that could be both a reason for initial Arab success in the "sandy" bits and a reason for a later lack of success in Europe and India.