When Doomsday arrives it is almost certain to be in the form of H-bombs exploding over thousands of targets throughout the world. When this happens many will be killed on the first day or two, but almost everyone will die within a year of the big day. The Northern Hemisphere will be particularly hard hit because that is where most of the high value military targets are, and where most of the industry is located, and where most of the people reside. Food production will come to a complete halt, and only those who have access to over a year’s supply of stored food will have any chance of survival. It is impossible to say much about the Northern half of the Southern Hemisphere because there isn’t much reason to attack any countries south of the equator but since WW III is an act of absolute suicidal madness by the contending parties, and they are in a particularly maddened state of mind their actions will become totally insane.
If many attacks occur in the south they will probably be where the population resides because there are few really super high value targets requiring an H-bomb for their destruction. Attacks of this type upon a population center are an absolute war crime, and we must condemn them, and their perpetrators now because we will not have much of a chance later on. All of that being said there is still the hope, a feeble hope, that those residing fairly far south in the Southern Hemisphere might survive unscathed, and even live normal lives during, and after the Doomsday events. Below is a map of where these survivors will be residing on that day.
A quick glance at this squeezed but equal area map shows how very little land mass there is in the natural low impact survival zone. The land masses are limited to Tasmania -42.88 +147.33 population about 494,000, South New Zealand -46.41 +168.36 about 2,000,000, Southern Chile about 242,000 people and Southern Argentina -45.88 -67.52 with about 710,000. There are a few islands sprinkled in this zone—Chatham Islands -43.95 -176.55 with about 1,000 people and Falklands -51.70 -57.84 with about 3,000, but beyond those 3,450,000 people in the survival zone there are fewer than a thousand living in that vast oceanic area. The Antarctic is placed below the natural survival zone because it is nearly impossible to live there without a substantial outside supply of food, and that would be interrupted after Doomsday. Even the tip of South America is so far south it is all but uninhabited. Falkland Islands are to be avoided because they may be a target of aggression as there is a major effort to maintain a military presence there since the Falklands war. Chatham Islands are good, but are militarily undefended in this Doomsday situation, but are unlikely to need defending.
Punta Arenas -53.15 -70.91 and Ushuaia -54.80 -68.30 are big towns, and plenty far south, but they might be targeted just because they are choke points between the Pacific and Atlantic oceans just like the Panama Canal. When Google Earthing from 42° south and on down there were surprisingly few towns. They were pretty, but they didn’t seem to have much in the way of food producing potential for a large community, and therefore would be dependent upon imported food which will not be arriving. There are vast areas out in Argentina with little apparent economic development, and therefore that location will probably not be adequate to survive in when things get even tougher. Chili Chico -46.54 -71.72 looks like it might be self sustaining, food wise because they have some farms right beside the town, but it is hard to know their import of basic foods.
Tasmania looks like a wonderful place to live at present, and the area around Hobart -42.88 +147.33 is cosmopolitan with surrounding farmland, and it would be a excellent choice.
New Zealand is wonderful, and has lots of farms apparent in the Google Earth images even to the far south near Invercargill -46.41 +168.36 so it appears that it is self sustaining. It may be the most likely place on Earth to have a future untroubled by Doomsday. Their current political policy is friendly, but very defensive of their local rights so it is unlikely to be attacked directly. They are far enough away from fallout zones not to be crippled by radiation or nuclear winter overcast. They are economically sound at present, and would enter a near future Doomsday in good economic health. Of course, the extreme problems will reach there too, but they may be survivable.