To survive, people will have to form groups. Within the groups there will have to be rules and some ethic--a meta-rule--to determine what those rules should be. If civilization got rebuilt, it would be good to have a better ethic embedded in human culture.

If you subscribe to Netflix, I heartily recommend the series, "Jericho." I watched it after I wrote that piece. It's a similar scenario; the collapse of civilization is not climate-based or complete, but localities are on their own in it.