Hokay, decided to do a map for the aftermath of Brook’s “World War Z” at the time the “oral history” is supposedly going to press.
(The Zombie plague seems to be occurring starting 2008, given the talk in the book about “cleaning up eight years of mess”, the thinly disguised president Colin Powell and VP Howard Dean, although the tech level seems in some ways more advanced than you’d expect only three years or so after Brooks wrote the book, so the “Panic” would be starting in 2009. Judging from a Cuban character commenting on the difference between Cuba today and 20 years ago, I put the date at 2029).
Warning: massive walls of text.
The US has regained control over all of its territory, although there still are dangers from Zombies occasionally walking out of the ocean or defrosting in mountain ice as the weather warms up from the post-Panic “nuclear autumn” conditions. Although poorer per capita than Cuba, its overall economy is still the world’s largest. It managed to save nearly a third of its population, an unusually high percentage for non-island nations.
Most US emigrants went home from Cuba after the troops were demobilized, but others came from Latin America and elsewhere: Cuba now has nearly twice its pre-war population.
Poor and ill-prepared for anti-zombie warfare, and with no cold season for Zombie activity to cease, most of Central America was badly devastated, and absorbed by Mexico post-war: the new greater Mexico has been renamed Aztlan (part of a creepy “Aztec revival” movement in Mexico, obsessed with death and warfare in art, culture, personal Machismo, etc.)
Brazil screwed up badly, and only managed to create a safe zone in the south: while they did pick up Uruguay (and a nasty military dictatorship), their population losses were the highest of any American nation maintaining a functional government post-war, and most of the north remains thinly governed if at all.
The few surviving Jamaicans voted to join the US (its immigrants making it the largest Jamaican nation on earth).
The Irish were initially sufficiently unpopular as a refuge to manage to contain their outbreaks, and what with refugees they now have half again OTLs population: the UK was not as successful, and their old islander suspicions of the mainland have revived, leading them to break with the post-war EU when it moved to become something closer to a “united states of Europe”, many populations having become mixed and reshuffled in the various refuge areas. Although losses varied (with Switzerland doing best, surprise surprise), overall they were higher than the US, given the greater population density, a largely unarmed populace, and a lot of flat land (zombies, unless they sense prey, tend to drift downhill in a “path of least resistance” manner), on the average losses were not as bad as such places as China or India or Brazil.
Sicily also became a refuge, but less secure than the mountains, suffered a severe outbreak, the political fallout of which persists. (For once in their existence, the Mafia performed heroically, their macho self-image not allowing them anything but the most determined effort to be the one to cap the most Zed-heads).
The Ukraine survived the war, barely. It is still looking very shaky, and is struggling to avoid falling under Russian control: efforts to become an EU associate have led to Russian threats (the EU nations don’t really know if the Russians have been able to maintain any of their nuclear arsenal over 20 years of chaos, but they’d rather not find out the hard way.), and the EU doesn’t particularly like the dictatorial Ukrainian government, or the restrictions on travel it has imposed to prevent further a drain of population to the west. Of course, there are those who demand standing up to Russian bullying. There is a lot of debate as to whether the Russians are really crazy, or just indulging in Nixonian “madman” posturing: what is known is that the Holy Russian Empire is a dictatorship of Stalinist nastiness, with control so tight that it has been able in a decade to bring up birth rates to 1980s third world levels, increasing population by a third from post-war lows (not that the war is entirely over in Russia: Zombies continue to thaw out every Siberian spring).
US Talking Heads gravely ruminate that at current growth rates Russia will surpass the US in population in 40 years: other Talking Heads grumble that the likelihood of the Russian state maintaining current levels of repression for that length of time are, to say, the least, remote.
Africa remains a mess: although a surprising number of individual Africans managed to survive (already used to dealing with deadly disease, murderous killers, living off the wilderness, and with lots of Cold War surplus weapons at hand…) few of the ramshackle governments survived, and while tropical zombies rotted fast enough that by the time more developed nations were ready to give a hand they were mostly already “non-functional”, much of the interior remains a chaos intermittently controlled by various petty warlords. The UN controls the coasts and prevents marine zombies from passing inland (mostly) but it is stretched thin over a vast area and member nations still remembering how much better they had it before World War Z are reluctant to pony up more funds. Some South African politicians have ambitions of unifying the whole continent.
The French managed to avoid accusations of racism by rescuing blacks and Muslims in percentages comparable to their share of the total population pre-war: some grumble that their encouragement of French Algerians and Tunisians in their efforts to restore their depopulated nations is, however, just a means of getting the Africans out of France for good and all. Much of the Middle East was heavily depopulated, although there were pockets of survivors in the Yemeni mountain fortresses, in the Bedu wastelands, and especially in the mountains of Turkey, Kurdish and otherwise: Kurds and Turks managed to sink their differences in fighting the living dead, and since the war Turkey has expanded greatly into the depopulated lands of Syria and Iraq.
The heroic defense of the Kaaba in Mecca, resupplied by Arab pilots on begged, borrowed, and stolen fuel for two years until some reinforcements finally arrived from Turkey and Indonesia, is an epic tale: still, world Islam has been particularly badly hit by the war. The loss of Egypt, with its thin line of population in the midst of a refuge-free desert which also allowed endless “flanking” possibilities by the undead, was a particularly hard blow, as was the suicidal nuclear exchange between Iran and Pakistan which helped bring about the collapse of both nations.
Palestinians have done quite well with their fixer-upper of a nation, so much so that a number of Israeli Arabs have emigrated. Mutterings similar to those re the French are often heard.
India suffered very high losses, both from Zombie attack and from starvation in the safe zones: efficient organization and quick perfection of new technologies not being India’s strongest points. Still, enough survived that with the absorption of the remnants of Pakistan, eastern Iran and Bangladesh India is now the world’s most populous nation. The economy remains shambolic, but nobody is starving anymore, and Indian commercial instincts remain unblunted.
Tibet is dominated nowadays by immigrants, the majority Chinese, but also Burmese, central Asian, Xinjiang Muslims and Indians and Nepalese who didn’t feel they were far enough away from the Living Dead. Many more came, but died of cold or hunger in the anarchic first years. Over a quarter of the population lives in the sprawling, 60%-slums, filthy, but very lively capital of Lhasa: with nearly three and a half million inhabitants, it is currently the world’s largest city (if not urban area), most major world cities having been overrun by Zombies and either burned or very slowly resettled since. The Dalai Lama, returned from India, has played a vital role in reconciling the immigrants with the native Tibetans, and has accepted the results of the election (in which a fair number of immigrants actually voted Lamaist out of admiration for him, but the Social Democrats still won by a big margin) with good grace.
China, where the government flatly refused to follow any version of the Redeker Plan and instead tried to fight the Zombies everywhere at once through a policy of truly universal mobilization, (and then fought a civil war while still fighting zombies) suffered the worst losses of any major nation, over 90% of its population dying, although there has been a bit of a postwar baby boom with the elimination of the pre-war One Child policy and the settlement of destitute peasants on newly available land. Politics are turbulent, and assassinations of the “guilty” are not infrequent, in spite of the observation of democratic forms.
Australia and New Zealand suffered from nasty outbreaks of their own, and are busily trying to attract European and North American immigration.
Indonesia lost most of densely populated (and too close to China by air) Java, and the government is currently dominated by religiously conservative types from Sumatra: the breakaway of the Moluccas rankles.
Japan only managed to get about a third of the population out to eastern Siberia, Taiwan, South Korea and the islands before things went truly pear-shaped, and the distinctly unhelpful attitudes of the Russian government let to a lot of Japanese freezing or starving to death. Since the idea of foreign immigration is less popular than ever (they might be plague-carriers!), Japan, along with several other countries, is attempting to encourage reproduction through legislation (some foreigners compare this to Holy Russia, but that doesn’t discourage the Japanese government), most recently through tax measures that shrink your taxes with every extra child you have (and increase them for every child less, people grumble) and punish those who don’t marry by twenty-five.
Japanese men, and some women, are bearing swords in public again.
Nobody knows where the hell the North Koreans went, (underground, presumably) but nobody really wants to be the one that opens the door and lets out 23 million hungry Zombies. Joint South Korean and Chinese patrols along the coasts make sure nobody sets foot in North Korea and starts digging around. Something will be done eventually, of course, but there is a lot of debate as to what, starting with sending in robot remotes and going up to building a Zombie-proof wall all along the border before doing anything else.
Technology has undergone some changes: self-sufficiency, large stocks of supplies, energy-efficiency and simplicity are all in, as are self-renewing energy and recycling. Biofuels, solar power, wind power, etc. are all big: nuclear power has not been helped by the meltdowns of various reactors abandoned by panicky employees, the Pakistan-Iran nuclear exchange, and the atomic decapitation attack ending the Chinese civil war. (This will eventually become a problem, but not yet, since demand is so shrunken from 2008). Space industry has come back online, mostly for satellite monitoring and communications. (Speaking of monitoring, everyone has close circuit cameras and plenty of them to, say, make sure something isn’t lurking outside the garage).
The environment is a mess: what with all the extra fishing while farmland was overrun with zombies, fish stocks have hit new lows, and huge areas of the ocean have suffered from what are essentially total collapses of the local ecosystem: some thinkers mutter uneasily about a “Permian extinction event.” Most large land animals have also been eaten by humans or zombies (although a few elephants have survived). Birds, much harder for zombies to catch, have generally done better. Rodents have multiplied horribly.
And still nobody can figure out how Zombies work.
 I think sapient Africans can do better than Quislings and Ferals, no?