Well, SAB-Miller did a scenario-planning exercise about this sort of thing and came up with some truly odd answers. In the worst-case scenario:
a market with limited access to water and high energy costs, where people would migrate from areas of water shortage or turbulent weather
their proposed solution involved installing a brewery aboard a ship, so it could sail to wherever the thirsty masses had pitched up. Interestingly, as the story was released through the Grauniad's "Guardian Professional" advertorial division, this is also something SABMiller management was willing to pay good money to tell us about. Time was when big business wanted to keep its apocalyptic fantasies secret.
(Tagged "uncategorized", but should probably be under "uncategorizable".)