When you come down to root causes, almost all wars are caused by resource control issues---They got it, we want it. [And yes, that includes the crusades. Look it up in Richardson's "The Statistics of Deadly Quarrels.] Iraq, of course is the exception. We really wanted to help those poor, misgoverned people over there to get rid of an evil dictator.

There were and are many people equally misgoverned who live in countries with few, if any, significant resources. We don't go out of our way to rescue them from their plight.

As far as water goes, we have reached the point where it is possible to clean water, either by reverse osmosis or chemically at a very low cost. It takes a lot of energy, but solar power is now efficient enough to do the job.