From a longer post on the David Kilcullen thread.

Water supply was one issue and he cited Syria as an example. Syria, with an expanding population for several years had issues over water supply, so much that water rationing applied in most cities. This was aggravated in 2010 with a drought in the south-east, which pushed more people into the cities and in 2011 two of those cities were where the protests began.

I've not heard of this before; no doubt it is fully explained in the book, but if anyone can add please do.