Good points, agree..finite resources, unlimited demand=tough choices...heard of gmos, they wont be a option and not just plants, how about gmo tuna, don't want it and your only option will be no tuna. consider this thought about urban....It may very well be the place to be for the majority. You can consentrate the resources for the largest,denses populations. Rural populations will for the most part likely be left to their own....not a bad thing for those able and capable.....for those less so, it can mean a return to the cities...just a thought. Also you don't have to look at just California for water shortage examples....I have niebourse whos wells produce less each year if not by volume by quality, in fact I can walk to one place were their second well is now going dry.