I expect there are many humans that could and have survived previous warring are concerned at the warring that could eventuate with the new technologies and the actions of the madmen of the Middle East.
Inhabiting conquered lands of post C21st conflict I don't believe will be as simple as you imply. Even the cleaning agents for aircraft fuel tanks leave toxic residues unfit for habitation, let alone viruses and defoliants. A few Iranian and Israeli nukes would render the joint uninhabitable well before rising sea level, spoiled crops, and biohazards. There are few limits to how despicable humans will be when faced with few options.
