Weird Harold wrote:
I don't think I'd count a sea level change into any post-apocalyptic scenario I'd write, just to preserve English as the Lingua Franca in my dystopia. Even tho' Spanish or Portuguese is more logical, if not the dominant Chinese dialect (Mandarin?)
In a "Final War" scenario, all major population centers in the Northern Hemisphere -- over, say, 100,000 population -- would be destroyed, leaving the Southern Hemisphere as the last population centers.
Australia, Tasmania, and New Zealand would be the last bastions of English speakers, but vastly outnumbered by Spanish/Portuguese South America and poly-glot India/Malaysia/Southern China.
The choice of Chicago is strictly Ameri-centric because the author is American.
I also think it seems unlikely that Chicago would survive this sort of destructive war, but that's based around early 21st century geopolitics.
For the same reason it seems unlikely to me that India, Pakistan, China, Japan etc. would survive a WMD war. In an all-out global war all the states with that kind of weapon and their enemies would be wiped out. Pretty much the only places I would see surviving relatively intact would be New Zealand, Madagascar and possibly Iceland, simply because they are sufficiently 'inoffensive' that they would not be deliberately targeted. I think Australia tends to stick its nose into geopolitics enough (and has sufficient military significance) that it might not survive such a war intact.