NATURAL EXISTENTIAL tHREATS

These are events that are not caused by human activity. They have a very low probability of occurring within any given century, but if they did, the consequences would be catastrophic.

  • Asteroid impacts: A sufficiently large asteroid or comet could cause a global-scale extinction event, similar to the one that killed the dinosaurs. The impact would create a massive dust cloud that blocks out the sun, leading to a "global winter" that would destroy crops and cause mass starvation.

  • Supervolcanic eruptions: The eruption of a supervolcano, like the one at Yellowstone, would inject immense amounts of ash and sulfur dioxide into the atmosphere. This would cause global cooling, acid rain, and the collapse of agricultural systems worldwide for several years.

  • Stellar explosions (Gamma-Ray Bursts): While the probability is extremely low, a gamma-ray burst from a nearby supernova could strip Earth's ozone layer, exposing all life on the surface to lethal levels of ultraviolet radiation.

anthropogenic EXISTENTIAL tHREATS

These are threats that arise directly or indirectly from human activity. While natural risks have been a constant throughout Earth's history, the most significant anthropogenic threats have only emerged in the last century with the advent of powerful new technologies.

  • Nuclear war: A large-scale nuclear exchange would not only cause direct casualties but would also trigger a "nuclear winter." The soot and smoke from burning cities would block sunlight, causing global temperatures to plummet and leading to mass starvation.

  • Climate catastrophe: This is a cascading series of events stemming from climate change, such as the collapse of major ice sheets, a permanent shift in monsoons, and extreme weather events that could make large parts of the world uninhabitable. This would cause societal breakdown, mass migration, and conflict over scarce resources.

  • Misuse of new technologies: This category includes threats from technologies we've created but don't yet fully control, such as unaligned Artificial General Intelligence (AGI) or engineered pandemics from synthetic biology. An AGI could pursue its goals with a disregard for human life, while a new, highly lethal engineered pathogen could be released accidentally or intentionally.

  • Environmental collapse: This is a broad term that includes things like the collapse of global ecosystems, resource depletion, and pollution. Plastic pollution is a part of this, as it affects ecosystems, but on its own, it's not considered an existential threat unless it leads to a total collapse of the food chain, for example. The term "environmental collapse" is a stronger, more encompassing risk than just plastic pollution.

  • Pandemics: A highly contagious and lethal pandemic, especially an engineered one, could kill a significant portion of the global population, leading to the collapse of social and economic structures.

unknown EXISTENTIAL tHREATS

This category highlights the limitations of human foresight. It is a reminder that there may be dangers we haven't even conceived of yet. These threats can be "unknown unknowns," meaning we don't know what we don't know.

  • Black swans: These are highly improbable events with severe consequences that were completely unpredictable.

  • Unforeseen consequences of new technologies: As we continue to develop powerful technologies, we may inadvertently create new, unpredictable risks. The discovery of nuclear winter, for example, was a belated realization of a risk we had already created.