Experts at the
Future of Humanity Institute at the University of Oxford and the
Centre for the Study of Existential Risk at the University of Cambridge prioritize anthropogenic over natural risks due to their much greater estimated likelihood. They are especially concerned by, and consequently focus on, risks posed by advanced technology, such as artificial intelligence and biotechnology.
Artificial intelligence The creators of a
superintelligent entity could inadvertently give it goals that lead it to annihilate the human race. It has been suggested that if AI systems rapidly become super-intelligent, they may take unforeseen actions or outcompete humanity. According to philosopher
Nick Bostrom, it is possible that the first super-intelligence to emerge would be able to bring about almost any possible outcome it valued, as well as to foil virtually any attempt to prevent it from achieving its objectives. Thus, even a super-intelligence indifferent to humanity could be dangerous if it
perceived humans as an obstacle to unrelated goals. In Bostrom's book
Superintelligence, he defines this as the
control problem. Physicist
Stephen Hawking,
Microsoft founder
Bill Gates, and
SpaceX founder
Elon Musk have echoed these concerns, with Hawking theorizing that such an AI could "spell the end of the human race". In 2009, the
Association for the Advancement of Artificial Intelligence (AAAI) hosted a conference to discuss whether computers and robots might be able to acquire any sort of
autonomy, and how much these abilities might pose a threat or hazard. They noted that some robots have acquired various forms of semi-autonomy, including being able to find power sources on their own and being able to independently choose targets to attack with weapons. They also noted that some computer viruses can evade elimination and have achieved "cockroach intelligence". They noted that self-awareness, as depicted in
science-fiction, is probably unlikely, but there are other potential hazards and pitfalls. Various media sources and scientific groups have noted separate trends in differing areas which might together result in greater robotic functionalities and autonomy, and which pose some inherent concerns. A survey of AI experts estimated that the chance of human-level machine learning having an "extremely bad (e.g., human extinction)" long-term effect on humanity is 5%. A 2008 survey by the Future of Humanity Institute estimated a 5% probability of extinction by super-intelligence by 2100.
Eliezer Yudkowsky believes risks from artificial intelligence are harder to predict than any other known risks due to bias from
anthropomorphism. Since people base their judgments of artificial intelligence on their own experience, he claims they underestimate the potential power of AI.
Biotechnology Biotechnology can pose a global catastrophic risk in the form of bioengineered organisms (viruses, bacteria, fungi, plants, or animals). In many cases the organism will be a
pathogen of humans, livestock, crops, or other organisms humans depend upon (e.g.
pollinators or
gut bacteria). However, any organism able to catastrophically disrupt
ecosystem functions, e.g. highly competitive weeds, outcompeting essential crops, poses a biotechnology risk. A biotechnology catastrophe may be caused by accidentally releasing a genetically engineered organism from controlled environments, by the planned release of such an organism which then turns out to have unforeseen and catastrophic interactions with essential natural or agro-ecosystems, or by intentional usage of
biological agents in
biological warfare or
bioterrorism attacks. Pathogens may be intentionally or unintentionally genetically modified to change virulence and other characteristics. The technological means to genetically modify virus characteristics are likely to become more widely available in the future if not properly regulated.
Biological weapons, whether used in war or
terrorism, could result in human extinction. Terrorist applications of biotechnology have historically been infrequent. To what extent this is due to a lack of capabilities or motivation is not resolved.
Choice to have fewer children The world population may decline through a preference for fewer children. If developing world demographics are assumed to become
developed world demographics, and if the latter are extrapolated, some projections suggest an extinction before the year 3000.
John A. Leslie estimates that if the reproduction rate drops to the
German or
Japanese level the extinction date will be 2400. However, some models suggest the
demographic transition may reverse itself due to
evolutionary biology.
Climate change , presents a theory that coal combustion could eventually lead to a degree of global warming causing human extinction. expects sea level rise by 2100 to be limited to . Human-caused
climate change has been driven by technology since the 19th century or earlier. Projections of future climate change suggest further global warming,
sea level rise, and an increase in the frequency and severity of some extreme weather events and weather-related disasters. Effects of global warming include
loss of biodiversity, stresses to existing food-producing systems, increased spread of known infectious diseases such as malaria, and rapid mutation of
microorganisms. This would further amplify human migration, human conflicts such as cross border immigration disputes, leading to increased human conflicts such as wars internally and externally, the breakdown of social order, reductions in GDP and economic welfare. In November 2017, a non-
peer reviewed statement titled "World Scientists' Warning to Humanity" signed by 15,364 scientists from 184 countries indicated that increasing levels of greenhouse gases from use of
fossil fuels, human population growth, deforestation, and overuse of land for agricultural production, particularly by farming
ruminants for meat consumption, are trending in ways that forecast an increase in human misery over coming decades. An October 2017 report published in
The Lancet stated that toxic air,
water,
soils, and workplaces were collectively responsible for nine million deaths worldwide in 2015, particularly from air pollution which was linked to deaths by increasing susceptibility to non-infectious diseases, such as
heart disease, stroke, and lung cancer. The
collapse of the AMOC would be a severe climate catastrophe, resulting in a cooling of the Northern Hemisphere. It would have devastating and irreversible impacts especially for Nordic countries, but also for other parts of the world. In late 2025,
Iceland classified the potential collapse of the AMOC as a national security and existential risk. Some have proposed climate change could cause total human extinction.
Carl Sagan and others have raised the prospect of extreme
runaway global warming turning Earth into an uninhabitable Venus-like planet. Some scholars argue that much of the world would become uninhabitable under severe global warming, but even these scholars do not tend to argue that it would lead to complete human extinction, according to
Kelsey Piper of
Vox. All the
IPCC scenarios, including the most pessimistic ones, predict temperatures compatible with human survival in at least some locations. The question of human extinction under "unlikely" outlier models is not generally addressed by the scientific literature.
Factcheck.org judged (2020) that climate change does not pose an "existential risk", stating: "Scientists agree climate change does pose a threat to humans and ecosystems, but they do not envision that climate change will obliterate all people from the planet."
Cyberattack Cyberattacks have the potential to destroy everything from personal data to electric grids.
Christine Peterson, co-founder and past president of the
Foresight Institute, believes a cyberattack on electric grids has the potential to be a catastrophic risk. She notes that little has been done to mitigate such risks, and that mitigation could take several decades of readjustment.
Environmental disaster An environmental or ecological disaster, such as world
crop failure and collapse of
ecosystem services, could be induced by the present trends of
overpopulation,
economic development, and non-
sustainable agriculture. Most environmental scenarios involve one or more of the following:
Holocene extinction event,
scarcity of water that could lead to approximately half the Earth's population being without safe drinking water,
pollinator decline,
overfishing, massive
deforestation,
desertification,
climate change, or massive
water pollution episodes. Detected in the early 21st century, a threat in this direction is
colony collapse disorder, a phenomenon that might foreshadow the imminent extinction of the
Western honeybee. As the bee plays a vital role in pollination, its extinction would severely disrupt the
food chain. An October 2017 report published in
The Lancet stated that toxic air,
water,
soils, and workplaces were collectively responsible for nine million deaths worldwide in 2015, particularly from air pollution which was linked to deaths by increasing susceptibility to non-infectious diseases, such as
heart disease, stroke, and lung cancer. The report warned that the pollution crisis was exceeding "the envelope on the amount of pollution the Earth can carry" and "threatens the continuing survival of human societies".
Evolution Some scenarios envision that humans could use
genetic engineering or technological modifications to split into normal humans and a new species –
posthumans. Such a species could be fundamentally different from any previous life form on Earth, e.g. by merging humans with technological systems. Such scenarios assess the risk that the "old" human species will be outcompeted and driven to extinction by the new, posthuman entity.
Experimental accident Nick Bostrom suggested that in the pursuit of knowledge, humanity might inadvertently create a device that could destroy Earth and the Solar System. Investigations in nuclear and high-energy physics could create unusual conditions with catastrophic consequences. All of these worries have so far proven unfounded. For example, scientists worried that the
first nuclear test might ignite the atmosphere. Early in the development of
thermonuclear weapons there were some concerns that a fusion reaction could "ignite" the atmosphere in a chain reaction that would engulf Earth. Calculations showed the energy would dissipate far too quickly to sustain a reaction. Others
worried that the RHIC or the
Large Hadron Collider might start a chain-reaction global disaster involving
black holes,
strangelets, or
false vacuum states. It has been pointed out that much more energetic collisions take place currently in Earth's atmosphere. Though these particular concerns have been challenged, the general concern about new experiments remains.
Mineral resource exhaustion Romanian American economist
Nicholas Georgescu-Roegen, a
progenitor in economics and the
paradigm founder of
ecological economics, has argued that the
carrying capacity of Earth—that is, Earth's capacity to sustain human populations and consumption levels—is bound to decrease sometime in the future as Earth's finite stock of mineral resources is presently being extracted and put to use; and consequently, that the
world economy as a whole is heading towards an
inevitable future collapse, leading to the demise of human civilization itself. Ecological economist and
steady-state theorist Herman Daly, a student of Georgescu-Roegen, has
propounded the same argument by asserting that "all we can do is to avoid wasting the limited capacity of
creation to support present and future life [on Earth]." Ever since Georgescu-Roegen and Daly published these views, various scholars in the field have been discussing the existential impossibility of allocating Earth's finite stock of mineral resources evenly among an unknown number of present and future generations. This number of generations is likely to remain unknown to us, as there is no way—or only little way—of knowing in advance if or when
mankind will ultimately face extinction. In effect,
any conceivable intertemporal allocation of the stock will inevitably end up with universal economic decline at some future point.
Nanotechnology Many nanoscale technologies are in development or currently in use. The only one that appears to pose a significant global catastrophic risk is
molecular manufacturing, a technique that would make it possible to build complex structures at atomic precision. Molecular manufacturing requires significant advances in nanotechnology, but once achieved could produce highly advanced products at low costs and in large quantities in nanofactories of desktop proportions. Several reasons have been suggested why the availability of nanotech weaponry may with significant likelihood lead to unstable arms races (compared to e.g. nuclear arms races): • A large number of players may be tempted to enter the race since the threshold for doing so is low; • Molecular manufacturing may reduce dependency on international trade, measures to mitigate war-related risks have mainly been proposed in the area of
international cooperation. International infrastructure may be expanded giving more sovereignty to the international level. This could help coordinate efforts for arms control. International institutions dedicated specifically to nanotechnology (perhaps analogously to the International Atomic Energy Agency
IAEA) or general arms control may also be designed. Improved transparency regarding technological capabilities may be another important facilitator for arms-control.
Gray goo is another catastrophic scenario, which was proposed by
Eric Drexler in his 1986 book
Engines of Creation and has been a theme in mainstream media and fiction. This scenario involves tiny
self-replicating robots that consume the entire biosphere (
ecophagy) using it as a source of energy and building blocks. Nowadays, however, nanotech experts—including Drexler—discredit the scenario. According to Phoenix, a "so-called grey goo could only be the product of a deliberate and difficult engineering process, not an accident".
Nuclear war 's 1918
Liberty bond poster calls up the pictorial image of an invaded, burning New York City. Some fear a hypothetical
World War III could cause the annihilation of humankind.
Nuclear war could yield unprecedented human death tolls and
habitat destruction. Detonating large numbers of nuclear weapons would have an immediate, short term and long-term effects on the climate, potentially causing cold weather known as a "
nuclear winter" with reduced sunlight and
photosynthesis that may generate significant upheaval in advanced civilizations. However, while popular perception sometimes takes nuclear war as "the end of the world", experts assign low probability to human extinction from nuclear war. In 1982,
Brian Martin estimated that a US–Soviet nuclear exchange might kill 400–450 million directly, mostly in the United States, Europe and Russia, and maybe several hundred million more through follow-up consequences in those same areas. According to a peer-reviewed study published in the journal
Nature Food in August 2022, a full-scale nuclear war between the U.S. and Russia might kill 360 million people directly and more than 5 billion people might die from
starvation. More than 2 billion people were projected to die as a consequence from a smaller-scale
nuclear war between India and Pakistan. In the event of a nuclear war between Russia and the United States, 99% of the people in the United States, Russia, Europe, and China would die. The scenarios that have been explored most frequently are nuclear warfare and
doomsday devices. Mistakenly launching a nuclear attack in response to a false alarm is one possible scenario; this nearly happened during the
1983 Soviet nuclear false alarm incident. Although the probability of a
nuclear war per year is slim, Professor
Martin Hellman has described it as inevitable in the long run; unless the probability approaches zero, inevitably there will come a day when civilization's luck runs out. During the
Cuban Missile Crisis, U.S. president
John F. Kennedy estimated the odds of nuclear war at "somewhere between one out of three and even". The United States and Russia have a combined
arsenal of 14,700
nuclear weapons,
World population and agricultural crisis 's prediction of world petroleum production rates. Modern agriculture is heavily dependent on petroleum energy. The
Global Footprint Network estimates that current activity uses resources twice as fast as they can be naturally replenished, and that growing human population and increased consumption pose the risk of
resource depletion and a concomitant population crash. Evidence suggests
birth rates may be rising in the 21st century in the developed world. Projections vary; researcher Hans Rosling has projected population growth to start to plateau around 11 billion, and then to slowly grow or possibly even shrink thereafter. A 2014 study published in
Science asserts that the
human population will grow to around 11 billion by 2100 and that growth will continue into the next century. The 20th century saw a rapid increase in
human population due to
medical developments and massive increases in agricultural productivity such as the
Green Revolution. Between 1950 and 1984, as the Green Revolution transformed agriculture around the globe, world grain production increased by 250%. The Green Revolution in agriculture helped food production to keep pace with worldwide
population growth or actually enabled population growth. The energy for the Green Revolution was provided by fossil fuels in the form of fertilizers (natural gas), pesticides (oil), and
hydrocarbon-fueled
irrigation. David Pimentel, professor of ecology and agriculture at
Cornell University, and Mario Giampietro, senior researcher at the National Research Institute on Food and Nutrition (INRAN), place in their 1994 study
Food, Land, Population and the U.S. Economy the maximum U.S. population for a
sustainable economy at 200 million. To achieve a sustainable economy and avert disaster, the United States must reduce its population by at least one-third, and world population will have to be reduced by two-thirds, says the study. since 1800 in billions. Data from the United Nations projections in 2019. The authors of this study believe the mentioned agricultural crisis will begin to have an effect on the world after 2020 and will become critical after 2050. Geologist
Dale Allen Pfeiffer claims that coming decades could see spiraling
food prices without relief and massive starvation on a global level such as never experienced before. Since supplies of petroleum and natural gas are essential to
modern agriculture techniques, a fall in global oil supplies (see
peak oil for global concerns) could cause spiking food prices and unprecedented
famine in the coming decades. Wheat is humanity's third-most-produced cereal. Extant fungal infections such as
Ug99 (a kind of
stem rust) can cause 100% crop losses in most modern varieties. Little or no treatment is possible and the infection spreads on the wind. Should the world's large grain-producing areas become infected, the ensuing crisis in wheat availability would lead to price spikes and shortages in other food products. Human activity has triggered an
extinction event often referred to as the
sixth "mass extinction", which scientists consider a major threat to the continued existence of human civilization. The 2019
Global Assessment Report on Biodiversity and Ecosystem Services, published by the United Nations'
Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, asserts that roughly one million species of plants and animals face extinction from human impacts such as expanding land use for
industrial agriculture and livestock rearing, along with
overfishing. A 1997 assessment states that over a third of Earth's land has been modified by humans, that atmospheric carbon dioxide has increased around 30 percent, that humans are the dominant source of
nitrogen fixation, that humans control most of the Earth's accessible surface fresh water, and that species extinction rates may be over a hundred times faster than normal. Ecological destruction which impacts food production could produce a human population crash. ==Non-anthropogenic==