Gene Barrels in Antarctica are the easy solution to the long term survival of humanity, because after the Doomsday wars there will need to be a source for recovery of the genetic heritage of billions of years of evolution of life on Earth. It is only in Antarctica where we can be certain of a thousand year storage of seeds, and it is upon the food that these seeds will create that humanity will thrive.
With the destruction of many if not most of the food producing crops in the currently habitable world at Doomsday the surviving humans will have a pitifully small number of foods from which to choose. It is very difficult to know, but people might be reduced to eating what we now consider to be slime. The problem becomes how to get large quantities of every possible gene into a safe and very cold storage place where they can survive totally untended by humans for thousands of years. With global warming certain to continue for at least a hundred years, most if not all glaciers, and other icy spots outside of Antarctica will melt. Therefore, even carefully tended seed-banks such as the one at a “bomb proof” facility called the Svalbard International Seed Vault will probably prove futile in the long run. In this case the long run may be as short as one hundred years, but certainly if things proceed as they presently are, one thousand years is an impossibility for that site. A thousand years sounds like a long time, but the thing under consideration is humanity which has a hundred thousand year long life history, and even civilization has several thousand years to look back upon. Thus a thousand year projection is reasonable, and the only reliable seed bank site is the two kilometer thick ice sheet in central Antarctica. At first glance this seems a formidable obstacle to reach but it can be done, and is presently being done routinely.
Here is a cheap and easy way to create a gene bank using some standard ISO containers (known as shipping containers, ITUs (Intermodal Transport Units) or isotainers) that can be loaded and sealed intact onto container ships, railroad cars, planes, and trucks. Some of these isotainers must wear out at some time for commercial use, and be discarded, but they would still be usable for this deep cold storage purpose. By having sites throughout the world where isotainers were located it would be possible to mail a personal gene barrel to a nearby collection point where the container would be loaded with local genetic material for that area. This might even be sponsored locally. When it was full the isotainer could be transported, space available, to a central collection site from which ships are occasionally bound for Antarctica, such as New Zealand, Tasmania, South America and South Africa. If these were taken on board a ship on a space available low priority standing the cost would be quite modest. Also as this program developed in popularity it might prove possible to get private funding. Once the containers were offloaded in Antarctica it would be best to transport them quite a ways inland, and that would require a special effort. It would not be necessary to transport them all the way to the South Pole seed vault site, but at least they should go to a place where they would be totally safe from all predators. Because these containers are large enough to be economically valuable, and have enough food in the form of seeds it is desirable to move them quite a ways inland, and separate them from one another. The goal of these gene banks is not to feed people directly, but to supply a source of seeds from which to grow food and more seeds.
There will come a time in the future, perhaps within the lifetime of people now living, when the seeds, and other things, in these containers, will provide humanity with a second chance at survival.