The Great War was a global thermonuclear war caused by the Sino-American War. It resulted in the destruction of all participating nations and abroad, global disruption of climate and billions of casualties as a result of nuclear blasts, exposure to radiation and subsequent collapse of social and government structures. Mankind was set back several hundred years in the span of just two hours.
The nuclear holocaust was a direct result of the Sino-American War, a decade-long conflict that left both the United States and China exhausted. By 2077, a combination of attrition, loss of supply routes and offensives conducted by the United States across the front, left Chinese units in Alaska stranded and cut off from reinforcements. The liberation of Anchorage spearheaded by winterized T-51 power armor units under the command of General Constantine Chase marked the end of the Anchorage Reclamation, after a decade of war. General Jingwei, commander of the Alaskan theater, was killed in action.
The campaign in mainland China, which began with the amphibious landings at Shantou in 2074, was reinvigorated by gaining ground in Alaska and the deployment of T-51 units. However, as American soldiers pushed deeper into the mainland, Chinese resistance increased. By October, the situation transitioned from a rout into a stalemate. Despite a decade of war, there was no end in sight. Billions of dollars and thousands of casualties were spent in vain, despite taxes and various wartime revenues ensuring the federal government was able to fund a standing army the likes of which the United States had never seen before. In a desperate attempt to bolster the offensive and break the stalemate, bases across the United States were sealed and troops redeployed to provide more men for the meat grinder.
The situation was made worse by the fact that the oligarchs ruling the United States retreated to remote locations around the globe, expecting a last-ditch nuclear strike from China at any moment. The oil rig off the Californian coast was claimed by the president and key members of the junta, becoming the foundation of the future Enclave. The United States was leaderless, continuing on simply due to inertia. Roger Maxson's rebellion went unnoticed, despite a declaration of secession and open rebellion Nuclear war was inevitable, a fact determined by Robert House back in 2065, who arrived at the conclusion that a nuclear war was inevitable by 2080, at most.
Pressed against the wall with nothing to lose, the Chinese finally launched a nuclear first strike on October 23, 2077, in a last-ditch effort to knock America out of the game. The first Chinese subs were identified by the United States Pacific Fleet at 00:03 EST off the coast of California, moving into position. At 03:37 EST, a squadron of high-altitude bombers was sighted off the Bering Strait.
Six hours later, at 09:13 EST, the Integrated Operational Nuclear Detection System detected the first four missile launches and the United States went to DEFCON 2. Four minutes later, NORAD confirmation sealed the fate of the world. At 09:26 EST, the president ordered a retaliatory strike according to scenario MX-CN91. As American weapons were launched, the first Chinese nukes hit in Pennsylvania and New York at 09:42 EST. By 09:47 EST, most American facilities went offline.    
The nuclear exchange continued for two hours, until silence fell across the land. Both China and the United States were destroyed. The standard nuclear warhead used in the Great War was that of strategic nuclear warhead ranging from 200-750 kilotons in explosive yield with the occasional megaton yield warhead (such as the C-23 Megaton) being the outliers. This would actually be far worse for the Earth as the lower yield warheads would deposit more soil and debris into the lower atmosphere resulting in a much more concentrated fallout that would envelop the environment. The entire world had been blanketed with multiple nuclear strikes, most cities being hit multiple times, and the world and its entire ecosystem being irrevocably changed for centuries to come.
The results of the nuclear war were devastating, as they combined with biological and chemical weapons that saw widespread use during the Sino-American War. The most significant result was a global climate shift, manifesting as extensive desertification, particularly in New California. What was once the richest and important agricultural region saw many aquifers dry up and vast stretches of arable land turning to deserts. The Central Valley, the largest and most fertile valley in California, became a barren wasteland in the wake of the climate change.
The changes in climate led to widespread alterations of the ecosystem. The new climate meant that many plants could no longer grow or be cultivated, ranging from common vegetables to specialized crops, such as coca plants or opium poppies. Due to necessity, crop variants mutated by radiation were adopted by survivors, including mutated cabbage and maize. These cultivars thrived in the warm weather of the Southwest, with similar mutations proliferating across the colder climates of the northern reaches of the continent.
Animals were also adversely affected. The combination of radioactive fallout and various local mutagens, particularly the Forced Evolutionary Virus in New California, led to widespread mutation. By 2080, new species were created almost overnight, replacing animals that died out or were out-competed. The most notable mutated species to emerge from this melting pot of genotypes is the brahmin, a mutated Indian Brahman cattle variant. Once the mutation stabilized, the brahmin turned out to be well suited for the harsh conditions of the wasteland, requiring little water and relatively small grazing areas, while providing plenty in return, including milk, meat, leather, bone, transportation et cetera. As such, it rapidly became the most widespread livestock animal in New California and the backbone of many a wasteland economy.
The impact on humanity and civilization was severe and traumatic. Although emergency response units and elements of the National Guard were mobilized in the evening of October 22, their ability to provide aid to victims and refugees was hampered by the lack of centralized command and control resulting from electromagnetic pulses disabling most communications equipment. Despite efforts by the military to bolster relief efforts, the shock of the nuclear attack resulted in their morale crumbling and many deserting their posts. By the time radiation sickness began to set in among victims of the attack, the situation was hopeless as they were not receiving any supplies to aid the victims. Whiskey and painkillers were the only care available to most patients.
Those who lived outside of major cities or managed to escape them in the narrow window given by the sirens faced a much better chance of survival. (However, one exception of Las Vegas was spared a direct nuclear strike thanks to Robert House, who disabled or destroyed 68 out of 77 warheads heading for the city). Although suffering from the sudden loss of access to water, food and medical care, these survivors would go on to found new communities across the newly born wasteland, becoming the founding fathers of a new civilization struggling to rise from the ashes. These include Darkwater, the founder of Junktown, Angus of the Hub, the founders of Megaton and Diamond City, and so on and so forth. Some of the less fortunate survivors on the surface would turn into ghouls, a result of their exposure to radioactive fallout and/or thermal radiation from the blasts, with their horrifying appearance leading to prejudice among other human survivors.
A relative few were able to reach safety in underground Vaults constructed by the Vault-Tec Corporation at the behest of the federal government, often trading suffering on the surface for suffering in confinement, due to the social experiments initiated by the forebears of the Enclave. Some refused to go into their assigned Vaults, believing it was just another drill and not realizing the truth until it was too late. Vaults that did not fail as a result of their experiment would frequently become another source of civilization across the wastelands, such as Vault 15, whose inhabitants founded Shady Sands (and the raider tribes of Khans, Vipers and Jackals), the Los Angeles Vault, which led to the establishment of Adytum, and Vault 8, which led to Vault City.
- There was debate on what time the Great War occurred and whether it happened in the morning or at night due to several inconsistencies being created throughout the Fallout games.
- All clocks on the East Coast are stuck at 9:47.
- In the Fallout: New Vegas add-on Honest Hearts, clocks found in the debris of Three Marys are also stopped at 9:47. This is despite the fact that Three Marys would be several time zones away from the East Coast, and so simultaneous bombings would not result in the same time stuck on the different clock faces.
- Though as Fallout: New Vegas borrows some textures and models from Fallout 3, it could be a lack of texture change.
- According to the Fallout: New Vegas add-on Dead Money, the bombs were launched during the night of the Gala Event, suggesting that the nuclear holocaust happened when people were sleeping on the East Coast and getting home from work on the West Coast. This also supports the ideas that people simply did not heed the air raid sirens or didn't have enough time to get to safety.
- According to Carrie Delaney's holotapes, the school was packing up to leave Little Lamplight after a field trip. This could place the East Coast bombs in the 2–3 PM time range, unless they had stayed overnight prior.
- Mr. House, meanwhile, says that the platinum chip was to be delivered in the afternoon of October 23, "but by then, the world had ended."
- The beginning of Fallout 4 starts out in pre-War Boston in the morning, only moments before the bombs fall, showing that the Great War occurred at 9:47am Eastern time, rather than at night. New York and Pennsylvania were hit at 9:42am, with Boston and Washington, D.C. being hit at 9:47am, five minutes after.
- This would mean the West Coast was hit around 6:30-6:40 AM, due to the differing time zones and travel time for the missiles. This is before sunrise in October, so it would technically still be night.
- The war is sometimes referred to as World War III by fans and on the Fallout Trilogy PC cover. In the Fallout intro, the narrator states that "the storm of world war had come again." However, none of the in-game characters in the series have ever referred it as such.
- In real life, however, a nuclear holocaust is usually associated with the hypothetical World War III.
Behind the scenes
|The following is based on the canceled Fallout movie and has not been confirmed by canon sources.|
According to the script of the Fallout movie, neither China, India nor North Korea launched the first bomb. It was in fact Vault-Tec Industries' executive of the vaults. He launched the first bomb to fulfill his own prophecy of nuclear annihilation. This has not been established as canon.
|End of information based on the canceled Fallout movie.|