World War Z, or the Zombie World War, is an apocalyptic event that devastates the Earth and nearly wipes out humanity in Max Brooks' horror novel of the same name. The book is written as a series of different tales and accounts of people who survived the event, describing events leading up to the global catastrophe, the many battlefronts of the war itself and the aftermath.
Origins
The cause of the undead menace that would sweep across the world is a virus known as Solanum. This disease had a 100% fatality rate and could affect any known animal life, usually killing it within hours of infection (this is variable depending on the strength of an infectee's immune system). In the case of human beings, the virus not only killed its victims but reanimated their corpses, turning them into mindless, bloodthirsty monsters commonly referred to as "zombies". It is unknown where the Solanum virus originated from and there have been numerous zombie outbreaks occurring in different parts of the world throughout history that make it extremely difficult to narrow down a point of origin. However, the outbreak that led to World War Z is believed to have occurred in China, in a town near the Yang-Tze River.
The Yang-Tze outbreak is supposedly contained and the Chinese government concoct a cover story involving Taiwan, but the infection spreads to other countries through the black market organ trade. Wealthy individuals would illegally purchase organs for transplant, not checking where the organs had come from and thus dooming themselves to zombification and in turn spreading the virus.
The Great Panic
The Great Panic was a period when the infection had become widespread across the world, causing whole countries to descend into chaos as the zombies multiplied and human populations began to decline. In the Middle East, this led to the annihilation of entire countries, and not through the undead's consumption of the living; Iran, suffering a tremendous influx of refugees from Pakistan, waged a nuclear war against Pakistan. Both countries were completely destroyed in the nuclear exchange.
Countries that have yet to experience heavy zombie incursions each take their own steps to try and stem the tide of infection and maintain order among their citizens. In the case of the United States, citizens start buying Phalanx, a new pharmaceutical product that supposedly serves as a vaccine against the zombie virus. It is soon revealed, however, that Phalanx is merely a placebo and that the people who produced it are con artists profiting off of people's fear. By the time the American public start to take the zombie threat seriously, the undead are already swarming through the streets in several cities and efforts to contain them are proving to be ineffective.
One country that did adequately prepare for the zombie threat was Israel. The country closed its borders, forbidding any outsiders from entering by land, sea or air, and massive walls were constructed around the cities that would keep out the undead should any hordes wander into the country from neighbouring countries or rising from the coast after walking across the ocean floor.
Two years following the Yang-Tze outbreak, mankind had been pushed to the brink of extinction. Over 70% of the planet's human population had been wiped out, whole continents were now solely inhabited by zombies. Survivors from various nations had gathered aboard flotillas of ships at sea and established new communities that would wait out the crisis, holding out until the zombies eventually rotted away.
The Redeker Plan
The Redeker Plan was developed by an ex-Apartheid government official, Paul Redeker, and copied by other nations (with varying names and details). It was determined that an entire population could not be saved, due to a lack of resources and the dangers of infection. "Safe zones" were established for some civilians and cleared of all zombies by military personnel. However, some of these safe zones were actually false safe zones, designed to relieve pressure from the actual safe zones. They would be set up and supplied in other sanctuaries, to draw zombies away from the safe zones and allow the people there time to regroup and reorient. In many cases false safe zones were developed in unsustainable positions. Hundreds of thousands were lied to and sacrificed in this manner, although reports of millions were present.
During this time immediately following the Great Panic, the focus was on the restructuring of the United States government, military, and civilian population. Many military tactics were changed in light of the new foe, and new tools of war and industry were invented and implemented by the U.S. government. The seat of the government was moved to Honolulu, Hawaii.
Total War
Once the Western United States is declared adequately fortified from the mega-hordes of zombies, it is determined that humanity need only wait out the zombies, as they will eventually all decay (over many years, sustained by the incomprehensibly resilient properties of Solanum), lose locomotion, and be more easily disposed of. However, a growing movement argued that the reclamation of land and the extermination of zombies was vital to the common spirit of all humanity. From Honolulu, The United States began to plan its counter-offensive against the global zombie horde; both to reclaim territory and to rekindle morale.
The challenge was admittedly daunting. It is impossible for any human nation to engage in a "total war" in which 100% of the population is devoted to the war effort, 24 hours a day. However, zombies devote every second of every day to hunting down and consuming humans. They never sleep and require no logistical support. Their lack of any sort of organization made impossible the use of tactics dating to the Bronze Age, such as the disruption of the chain of command or the killing of the enemy general. Each zombie is a self-contained fighting unit that can function for years without resupply, relief, or reinforcement.
The use of a new rifle, called the Standard Infantry Rifle or SIR which sacrificed ease and rate of fire for accuracy, ease of manufacture and reliability (Todd Wainio said that it never jammed on him), along with a new type of incendiary ammunition (PIE; Pyrotechnically Initiated Explosive) allowed for armies to cut down zombies methodically and effectively. Pre-modern warfare infantry squares became a predominant tactic against the living dead. Battles consisted of the unit forming rank and file and luring the zombies into their prepared killzones. They fired on the horde as they cross a series of range markers, eventually forming a wall of dead zombies that the others have to climb over. Once zombies started to appear from multiple directions (as they almost always did), the troops would form a square shape around their vehicles, as to protect the centre. This method was copied from General Raj-Singh, who attempted to use a square to face off thousands of zombies in India, a successful tactic until his troops ran out of ammunition and were overrun. These new tactics were first employed on a large scale in the United States at the Battle of Hope.
Eventually the United States managed to recapture its entire territory by forming two lines of infantry that stretched across the United States and marching across the country. "The Road to New York", as the campaign was called, lasted roughly three years. After this is done, the U.S. military helps the Canadian and Mexican forces retake their countries. Europeans manage to retake their countries. Russia reconquers its territory, with the exception of parts of Siberia, but suffers a vastly higher casualty rate than the U.S. and Europe due to woefully inadequate supplies and equipment. North America is cleared of zombies ten years after the beginning of the war. When China is cleared of zombies two years after that, 'VC Day' (Victory in China Day) is declared: the official end of the Zombie War.
It is implied that tribal groups such as South American Indians, Zulu of Southern Africa and Māori of New Zealand fared surprisingly well. One character relates an anecdote about the Māori taking on half of the Auckland horde, using traditional tribal weapons, did much better than the world's various military forces or Western civilians.
After the war
Although humanity was able to pull itself back from the brink of extinction and reclaim its territories from the undead, the environmental situation following the war is tenuous. The Earth's ecosystem has been heavily damaged with large areas of land contaminated by rotten zombies and saturated with toxins and even radiation in the cases of some countries. The number fires left to burn from blitzed cities, unattended chemical factories and nuclear facilities, not to mention the pyres for disposing of zombies, have caused widespread contamination of the atmosphere. Numerous water sources have been polluted and a large number of animal species have become extinct, due both to zombie consumption and over-hunting by humans struggling to survive.
While the zombie population has been mostly eradicated on land, enormous hordes of zombies still exist on the ocean floor, making fishing and drilling for resources exceedingly difficult in many areas of the sea.
The world's geographical and geopolitical maps have been entirely re-drawn. Whole countries were annihilated over the course of the war, most notably Pakistan and Iran which destroyed each other in a nuclear exchange. Other countries that had suffered from poor political structuring and economic crises pre-war have since become more prosperous after the conflict. Countries that enjoyed booming economies pre-war, such as China, have gone into economic decline post-war, as well as facing major political and social upheaval.