Global catastrophic risk

A global catastrophic risk or a doomsday scenario is a hypothetical future event that could damage human well-being on a global scale, even endangering or destroying modern civilization. An event that could cause human extinction or permanently and drastically curtail humanity's potential is known as an "existential risk." Over the last two decades, 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. The term global catastrophic risk "lacks a sharp definition", and generally refers (loosely) to a risk that could inflict "serious damage to human well-being on a global scale". Humanity has suffered large catastrophes before. Some of these have caused serious damage but were only local in scope—e.g. the Black Death may have resulted in the deaths of a third of Europe's population, 10% of the global population at the time. Some were global, but were not as severe—e.g. the 1918 influenza pandemic killed an estimated 3–6% of the world's population. Most global catastrophic risks would not be so intense as to kill the majority of life on earth, but even if one did, the ecosystem and humanity would eventually recover (in contrast to existential risks). Similarly, in Catastrophe: Risk and Response, Richard Posner singles out and groups together events that bring about "utter overthrow or ruin" on a global, rather than a "local or regional", scale. Posner highlights such events as worthy of special attention on cost–benefit grounds because they could directly or indirectly jeopardize the survival of the human race as a whole. Existential risks are defined as "risks that threaten the destruction of humanity's long-term potential." The instantiation of an existential risk (an existential catastrophe) would either cause outright human extinction or irreversibly lock in a drastically inferior state of affairs.