Human extinction in the context of "Timeline of the far future"

A global catastrophic risk or a doomsday scenario is a hypothetical event that could damage human well-being on a global scale, endangering or even destroying modern civilization. Existential risk is a related term limited to events that could cause full-blown human extinction or permanently and drastically curtail humanity's existence or potential.

In the 21st century, a number of academic and non-profit organizations have been established to research global catastrophic and existential risks, formulate potential mitigation measures, and either advocate for or implement these measures.

Apocalypticism is the religious belief that the end of the world is imminent, even within one's own lifetime. This belief is usually accompanied by the idea that civilization will soon come to a tumultuous end due to some sort of catastrophic global event.

Apocalypticism is one aspect of eschatology in certain religions, the part of theology concerned with the final events of human history, or the ultimate destiny of humanity (societal collapse, human extinction, and so on).

Nuclear warfare, also known as atomic warfare, is a military conflict or prepared political strategy that deploys nuclear weaponry. Nuclear weapons are weapons of mass destruction; in contrast to conventional warfare, nuclear warfare can produce destruction in a much shorter time and can have a long-lasting radiological result. A major nuclear exchange would likely have long-term effects, primarily from the fallout released, and could also lead to secondary effects, such as "nuclear winter", nuclear famine, and societal collapse. A global thermonuclear war with Cold War-era stockpiles, or even with the current smaller stockpiles, may lead to various scenarios including human extinction.

To date, the only use of nuclear weapons in armed conflict occurred in 1945 with the American atomic bombings of Hiroshima and Nagasaki. On August 6, 1945, a uranium gun-type device (code name "Little Boy") was detonated over the Japanese city of Hiroshima. Three days later, on August 9, a plutonium implosion-type device (code name "Fat Man") was detonated over the Japanese city of Nagasaki. Together, these two bombings resulted in the deaths of approximately 200,000 people and contributed to the surrender of Japan, which occurred before any further nuclear weapons could be deployed.

Nuclear warfare, also known as atomic warfare, is a military conflict or prepared political strategy that deploys nuclear weaponry. Nuclear weapons are weapons of mass destruction; in contrast to conventional warfare, nuclear warfare can produce destruction in a much shorter time and can have a long-lasting radiological result. A nuclear exchange would likely have long-term effects, primarily from the fallout released, and could also lead to secondary effects, such as "nuclear winter", nuclear famine, and societal collapse. A global thermonuclear war with Cold War-era stockpiles, or even with the current smaller stockpiles, may lead to various scenarios including human extinction.

As of 2025, the only use of nuclear weapons in armed conflict was the United States atomic bombings of Hiroshima and Nagasaki, on August 6 and 9, 1945, in the final days of World War II. The two bombings resulted in the deaths of between 150,000 and 246,000 people. A debate continues over ethical, legal, and military aspects of the bombings, including their role in the surrender of Japan.

Existential risk from artificial intelligence, or AI x-risk, refers to the idea that substantial progress in artificial general intelligence (AGI) could lead to human extinction or an irreversible global catastrophe.

One argument for the validity of this concern and the importance of this risk references how human beings dominate other species because the human brain possesses distinctive capabilities other animals lack. If AI were to surpass human intelligence and become superintelligent, it might become uncontrollable. Just as the fate of the mountain gorilla depends on human goodwill, the fate of humanity could depend on the actions of a future machine superintelligence.