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Globales existenzielles Risiko

2008-02-23T11:46:24Z

88.195.46.112: /* Humanity */ mentioned already

:''This is about the future of civilization, humans and the earth. For past civilizations, see [[societal collapse]].''
'''Risks to civilization, humans and planet Earth''' are [[existential risk]]s that would imperil mankind as a whole and/or have major adverse consequences for the course of human [[civilization]], [[human extinction]] or even the [[end of planet Earth]].<ref name="types">{{cite journal| authorlink=Nick Bostrom| first=Nick| last=Bostrom| year=2001| url=http://www.nickbostrom.com/existential/risks.html| title=Existential Risks: Analyzing Human Extinction Scenarios and Related Hazards| journal=Journal of Evolution and Technology| volume=9| month=March| year=2002}}</ref> The concept finds expression in various [[idiom|idiomatic]], phrases such as "[[End of the World]]", "[[Doomsday]]", "[[wikt:TEOTWAWKI|TEOTWAWKI]]", "TEOCAWKI" and others. 

==Types of risks==

Various risks exist for [[humanity]], but not all risks are equal. Risks can be roughly categorized into six types based on the scope of the risk (Personal, Regional, Global) and the intensity of the risk (Endurable or Terminal). This chart provides some examples.

{| border="1" cellspacing="0" cellpadding="2" class="wikitable"
!colspan="3" align="center"|'''Typology of risk''' <ref name="types" />
|-
!
!Endurable
!Terminal
|-
|'''Global'''
|Thinning of the ozone layer
|Global nuclear war
|-
|'''Regional'''
|Economic recession
|Genocide
|-
|'''Personal'''
|Theft of car
|Terminal illness
|}

The risks discussed in this article are those in the Global-Terminal category. This type of risk is one where an adverse outcome would either annihilate intelligent life, or permanently and drastically curtail its potential. For an alternative classification system see [[Jamais Cascio]]'s [http://www.openthefuture.com/2006/12/an_eschatological_taxonomy.html An Eschatological Taxonomy]. A problem for this system is the sheer size of humanity; even in the event of catastrophic nuclear war, total collapse of the ice sheets or ocean currents, or the rise of a devastating epidemic, it is extremely likely that some people will survive, though conventional civilization may collapse.

==Future scenarios==

There are many scenarios that have been suggested that could happen in the future. Some are certain to happen and will almost certainly end humanity, but may only happen on a very long timescale, or may happen sooner. Others are likely to happen on a shorter timescale, but will probably not completely destroy civilization. Still others are extremely unlikely, and may even be impossible. For example, [[Nick Bostrom]] writes:<ref name="unlikely">Nick Bostrom, section 4.7.</ref>
:''Some foreseen hazards (hence not members of the current category) which have been excluded from the list of bangs on grounds that they seem too unlikely to cause a global terminal disaster are: solar flares, supernovae, black hole explosions or mergers, gamma-ray bursts, galactic center outbursts, supervolcanoes, buildup of air pollution, gradual loss of human fertility, and various religious doomsday scenarios.''

===Space===

It is certain that events in space can cause [[life on Earth]] to come to an end. The certain events, however, will happen at an extremely long timescale measured in billions of years. Projections indicate that the [[Andromeda Galaxy]] is on a collision course with the Milky Way. Impact is predicted in about 3 billion years, and so Andromeda will approach at an average speed of about 140 kilometres (87 miles) per second; the two galaxies will probably merge to form a giant elliptical. This merging could eject the solar system in a more eccentric orbit{{Fact|date=February 2007}} and an unwanted position in the merged galaxy causing our planet to become uninhabitable (an actual collision is unnecessary). In about 5 billion years, [[stellar evolution]] predicts our [[sun]] will exhaust its core hydrogen and become a [[red giant]]. In so doing, it will become thousands of times more luminous.<ref>[http://hyperphysics.phy-astr.gsu.edu/hbase/astro/redgia.html Red Giants]</ref> Even in its current phase of stellar evolution, the sun is increasing in luminosity (at a very slow rate). Many scientists predict that in fewer than one billion years, the runaway [[greenhouse effect]] will make Earth unsuitable for life.{{Fact|date=October 2007}}

On an even longer time scale, the [[ultimate fate of the universe|universe may come to an end]]. The current [[age of the universe]] is estimated as being 13.7 billion years old. There are several competing theories as to the nature of our [[universe]] and how it will end, but in all cases, there will be no life possible. These scenarios take place on a considerably longer timescale than the expansion of the sun.

==== Meteorite impact ====

In the [[history of the Earth]], it is widely accepted that several large [[meteorite]]s have hit [[Earth]]. The [[Cretaceous-Tertiary extinction event|Cretaceous-Tertiary asteroid]], for example, is theorized to have caused the extinction of the [[dinosaur]]s. If such an object struck Earth it could have a serious impact on civilization. It's even possible that humanity would be completely destroyed: for this, the asteroid would need to be at least 1 km (0.6 miles) in diameter, but probably between 3–10 km (2–6 miles).<ref name="meteor">Nick Bostrom, section 4.10</ref> Asteroids with a 1 km diameter impact the Earth every 0.5 million years<ref name="meteor" /> on average. Larger asteroids are less common. The last large (>10 km) impact happened [[Cretaceous-Tertiary extinction event|65 million years ago]]. So-called [[Near-Earth asteroid]]s are regularly being observed.

Some scientists believe there are patterns in the number of meteorites hitting Earth. An interesting explanation of such a pattern is given by the hypothetical star [[Nemesis (star)|Nemesis]]. This hypothesis states that a star named Nemesis regularly passes through a denser part of the [[Oort cloud]], causing meteorite rains to collide onto Earth. However, the very existence of this pattern is not widely accepted, and the existence of the Nemesis star is highly contested.

A star passage that will cause an increase of meteorites is the arrival of a star called [[Gliese 710]]. This star is probably moving on a collision course with the [[Solar System]] and will likely be at a distance 1.1 [[light year]]s from the Sun in 1.4 million years. Some models predict that this will send large amounts of comets from the [[Oort cloud]] to the Earth.<ref>[http://www.exitmundi.nl/Gliese710.htm Date With The Neigbors: Gliese 710 And Other Incoming Stars]</ref> Other models, such as the one by García-Sánchez, predict an increase of only 5%.

==== Less likely cosmic threats ====






A number of other scenarios have been suggested. Massive objects, e.g., a [[star]], large [[planet]] or [[black hole]], could be catastrophic if a close encounter occurred in the solar system. Another threat might come from [[Gamma ray bursts#Mass extinction on Earth|gamma ray bursts]]; some scientists believe this may have caused mass extinction 450 million years ago.<ref name="gammaray">[http://www.nasa.gov/vision/universe/starsgalaxies/gammaray_extinction.html Explosions in Space May Have Initiated Ancient Extinction on Earth], [[NASA]].</ref> Both are very unlikely.<ref name="unlikely" /> Still others see [[extraterrestrial life]] as a possible threat to mankind;<ref name="aliens">[http://www.findarticles.com/p/articles/mi_m1511/is_10_21/ai_65368918 Twenty ways the world could end suddenly], Discover Magazine</ref> although alien life has never been found, scientists such as [[Carl Sagan]] have postulated that the existence of extraterrestrial life is very likely. In 1969, the "[[Extra-Terrestrial Exposure Law]]" was added to the Code of Federal Regulations (Title 14, Section 1211) in response to the possibility of biological contamination resulting from the US Apollo Space Program. It was removed in 1991.<ref>[http://www.snopes.com/legal/et.htm Urban Legends Reference Pages: Legal Affairs (E.T. Make Bail)]</ref> Scientists consider such a scenario technically possible, but unlikely.<ref name="aliensunlikely">Nick Bostrom, section 7.2.</ref>

===Earth===

In the history of the Earth, many [[ice age]]s have occurred. More ice ages will almost certainly come at an interval of 40,000–100,000 years. This would have a serious impact on civilization, because vast areas of land (mainly in [[North-America]], [[Europe]], and [[Asia]]) could become uninhabitable. It would still be possible to live in the tropical regions, but with possible loss of humidity/water. Currently, the world is technically existing in a warm period between such ice ages (the last ending c. 10000 years ago), and all civilizations (save a few hunter-gatherer populations) have come into existence within that time.

A less predictable scenario is a global [[pandemic]]. For example, if [[HIV]] mutates and becomes as transmissible as the [[common cold]], the consequences would be disastrous, but probably not fatal to the human species,<ref name="pandemic">Nick Bostrom, section 4.9.</ref> as some people are immune to HIV.<ref>[http://www.pbs.org/wgbh/evolution/library/10/4/l_104_06.html Evolution: Library: HIV Immunity]</ref> This particular scenario would also contradict the observable tendency for pathogens to become less fatal over time as a function of [[natural selection]]. A pathogen that quickly kills its hosts will not likely have enough time to spread to new ones, while one that kills its hosts more slowly or not at all will allow carriers more time to spread the infection, and thus likely outcompete a more lethal species or strain. A real-life example of this process can be found in the historical evolution of [[syphilis]] towards [http://www.qmul.ac.uk/news/newsrelease.php?news_id=9 a less virulent form]. Also as a virus mutates in a direction of being easily transmittable it will likely give up much of its virulence in the process. Though this is not to say that a highly destructive and highly transmissible disease is not possible. Of course, a pandemic resulting in human extinction need not arise naturally; the possibility of one caused by a deliberately-engineered pathogen cannot be ruled out.

Another possibility is the [[megatsunami]]. A megatsunami could, for example, destroy the entire east coast of the [[USA|United States of America]] (see [[La Palma]]). The coastal areas of the entire world could be flooded in case of the collapse of the [[West Antarctic Ice Sheet]].<ref name="wais">[http://igloo.gsfc.nasa.gov/wais/ US West Antarctice Ice Sheet initiative]</ref> While none of these scenarios could possibly destroy humanity completely, they could regionally threaten civilization.

An [[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 of these scenarios involve one or more of the following: [[Holocene extinction event]], [[Water crisis|scarcity of water]] that could lead to approximately one half of the Earth's population being without safe [[drinking water]], [[pollinator decline]], [[overfishing]], massive [[deforestation]], [[desertification]], [[climate change]], or massive [[water pollution]] episodes. A very recent 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]].

The 20th century has seen a rapid increase in [[human population]] due to [[History of medicine#Modern medicine|medical advances]] and massive increase in agricultural productivity<ref>[http://news.bbc.co.uk/1/hi/world/south_asia/4994590.stm BBC NEWS | The end of India's green revolution?]</ref> made by the [[Green Revolution]].<ref>[http://www.foodfirst.org/media/opeds/2000/4-greenrev.html Food First/Institute for Food and Development Policy]</ref> 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]]. The energy for the Green Revolution was provided by fossil fuels in the form of [[fertilizers]] (natural gas), [[pesticides]] (oil), and [[hydrocarbon]] fueled [[irrigation]].<ref>[http://wolf.readinglitho.co.uk/mainpages/agriculture.html How peak oil could lead to starvation]</ref> 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 theirs study ''Food, Land, Population and the U.S. Economy'' the maximum [[U.S. population]] for a [[sustainability|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 study.<ref>[http://www.energybulletin.net/281.html Eating Fossil Fuels | EnergyBulletin.net]</ref>

The authors of this study believe that the mentioned agricultural crisis will only begin to impact us after 2020, and will not become critical until 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.<ref>[http://www.soilassociation.org/peakoil Peak Oil: the threat to our food security]</ref><ref>[http://europe.theoildrum.com/node/2225 Agriculture Meets Peak Oil]</ref>

An abrupt [[Pole shift theory|reorientation of Earth's axis of rotation]] could cause a new [[extinction event]].<ref>{{cite web | url=http://www.nytimes.com/2006/10/12/science/earth/12extinct.html?ex=1176609600&en=9fc4a5a53674ca70&ei=5087&excamp=mkt_at8 | title=Study Links Extinction Cycles to Changes in Earth’s Orbit and Tilt | publication=[[The New York Times]] |date=2006-10-12 | author=Wilford, John Noble}}</ref>


When the [[supervolcano]] at [[Yellowstone National Park|Yellowstone]] last erupted, 600,000 years ago, the magma and ash covered roughly all of the area of North America west of the Mississippi river. Another such eruption could threaten civilization. Such an eruption could also release large amounts of gases that could alter the balance of the planet's carbon dioxide and cause a runaway greenhouse effect, or enough pyroclastic debris and other material may be thrown into the atmosphere to partially block out the sun and cause a natural [[nuclear winter]], similar to 1816, the [[Year Without A Summer]]. Such an eruption may cause the death of millions several hundred miles from the epicenter and overall hundreds of millions of deaths worldwide due to the failure of the [[monsoon]], causing starvation on an unthinkable scale.

Overall, '''Earth will be rendered lifeless once the Sun expands''' due to it running out of energy; the oceans will evaporate, and after the Sun shrinks, Earth will be too frigid to sustain life.


===Humanity===

Some threats for humanity come from humanity itself. The scenario that has been explored most is a [[nuclear warfare#current concerns|nuclear war]] or [[Doomsday device|another weapon]] with similar possibilities. It is difficult to predict whether it would exterminate humanity, but very certainly could alter civilization, in particular if there was a [[nuclear winter]] event.<ref name="nuclearwinter">Nick Bostrom, section 4.2.</ref>

Another category of disasters are [[technological singularity|unforeseen consequences of technology]].
It has been suggested that [[Artificial Intelligence#Hypothetical consequences of AI|learning computers]] take unforeseen actions or that [[Robot#possible dangers|robots]] would out-compete humanity.<ref name="billjoy">[[Bill Joy]], [http://www.wired.com/wired/archive/8.04/joy_pr.html Why the future doesn't need us]. In:[[Wired magazine|Wired]] magazine. See also [[technological singularity]].</ref>
[[Biotechnology]] could lead to the creation of a [[pandemic]], [[Nanotechnology]] could lead to [[grey goo]] - in both cases, either deliberately or by accident.<ref name="drexler">[[Eric Drexler]], [[Engines of Creation]], ISBN 0-385-19973-2, [http://www.foresight.org/EOC/ available online]</ref>
It has also been suggested that physical scientists might accidentally create a device that could destroy the earth and the solar system.<ref name="physicsaccident">Nick Bostrum, section 4.8</ref> In [[string theory]], there are some unknown variables. If those turn out to have an unfortunate value, the universe may not be stable and alter completely, destroying everything in it,<ref name="quantumtunneling">Malcolm Perry, ''Quantum Tunneling towards an exploding Universe?'' in: [[Nature]], [[24 April]] [[1986]]. [http://www.uhh.hawaii.edu/~dixon/quantum_tunneling.pdf available online].</ref> either at random or by an accidental experiment. This is called [[Quantum Vacuum Collapse]] by some.<ref name="qvc">[http://www.exitmundi.nl/vacuum.htm The day the Quantum Vacuum Collapsed]</ref> Another kind of accident is the ''[[Ice-9 Type Transition]]'', in which our planet including everything on it becomes a strange matter planet in a chain reaction. Some do not view this as a credible scenario.<ref name="ice9">Frank Wilczek, in an e-mail, [http://lists.nau.edu/cgi-bin/wa?A2=ind9907&L=phys-l&F=&S=&P=29937| This available online].</ref>

It has been suggested that runaway [[global warming]] might cause the climate on Earth to become like [[Venus]], which would make it uninhabitable. In less extreme scenarios it could cause the end of civilization.<ref name="runaway">Isaac M. Held, Brian J. Soden, ''Water Vapor Feedback and Global Warming'', In: Annu. Rev. Energy Environ 2000. [http://www.gfdl.noaa.gov/~gth/netscape/2000/annrev00.pdf available online]. Page 449.</ref> According to a UN climate report, the [[Himalayas|Himalayan]] glaciers that are the sources of [[Asia]]'s biggest rivers - [[Ganges]], [[Indus]], [[Brahmaputra]], [[Yangtze]], [[Mekong]], [[Salween]] and [[Yellow]] - could disappear by 2035 as temperatures rise.<ref>[http://www.planetark.com/dailynewsstory.cfm/newsid/42387/story.htm Vanishing Himalayan Glaciers Threaten a Billion]</ref> Approximately 2.4 billion people live in the [[drainage basin]] of the Himalayan rivers.<ref>[http://www.peopleandplanet.net/pdoc.php?id=3024 Big melt threatens millions, says UN]</ref> [[India]], [[China]], [[Pakistan]], [[Bangladesh]], [[Nepal]] and [[Myanmar]] could experience floods followed by [[droughts]] in coming decades. In [[India]] alone, the Ganges provides water for drinking and farming for more than 500 million people.<ref>[http://www.rediff.com/news/2007/jul/24indus.htm Ganges, Indus may not survive: climatologists]</ref><ref>[http://english.peopledaily.com.cn/90001/90781/90879/6222327.html Glaciers melting at alarming speed]</ref><ref>[http://news.bbc.co.uk/2/hi/science/nature/3998967.stm Himalaya glaciers melt unnoticed]</ref>

In [[Africa]], if current trends of soil degradation continue, the continent might
be able to feed just 25% of its population by 2025, according to [[United Nations University|UNU]]'s Ghana-based Institute for Natural Resources in Africa.<ref>[http://news.mongabay.com/2006/1214-unu.html Africa may be able to feed only 25% of its population by 2025]</ref>

[[James Lovelock]], creator of the [[Gaia hypothesis]], in his book ''[[The Revenge of Gaia]]'' (2006), has suggested that the elimination of [[rain forest]]s, and the falling planetary [[biodiversity]] is removing the [[homeostasis|homeostatic]] [[negative feedback]] mechanisms that maintain climate stability by reducing the effects of [[greenhouse gas]] emissions (particularly [[carbon dioxide]]). With the heating of the oceans, the extension of the [[thermocline]] layer into [[Arctic]] and [[Antarctic]] waters is preventing the overturning and nutrient enrichment necessary for [[algal blooms]] of [[phytoplankton]] on which the [[ecosystem]]s of these areas depend. With the loss of phytoplankton and tropical rain forests, two of the main [[carbon dioxide sink]]s for reducing [[global warming]], he suggests a runaway [[positive feedback]] effect could cause tropical [[desert]]s to cover most of the worlds tropical regions, and the disappearance of polar ice caps, posing a serious challenge to global civilization.

Using [[scenario analysis]], the [[Global scenario group]] (GSG), a coalition of international scientists convened by [[Paul Raskin]], developed a series of possible futures for the world as it enters a [[Planetary Phase of Civilization]]. One scenario involves the complete breakdown of civilization as the effects of [[climate change]] become more pronounced, competition for scarce resources increases, and the rift between the poor and the wealthy widens. The GSG’s other scenarios, such as [[Policy Reform]], [[Eco-Communalism]], and [[Great Transition]] avoid this societal collapse and eventually result in environmental and social [[sustainability]]. They claim the outcome is dependent on human choice<ref>[http://www.gtinitiative.org/documents/PDFFINALS/16WorldLines.pdf World Lines: Pathways, Pivots, and the Global Future]. [[Paul Raskin]]. 2006. Boston:[http://www.tellus.org Tellus Institute] </ref> and the possible formation of a [[global citizens movement]] which could influence the trajectory of global development.<ref> [http://www.gtinitiative.org/documents/PDFFINALS/15Movements.pdf Dawn of the Cosmopolitan: The Hope of a Global Citizens Movement] Orion Kriegman. 2006. Boston:[http://www.tellus.org Tellus Institute]</ref>

Other scenarios that have been named are:

; [[Antibiotic resistance]] : Natural selection would create super bacteria that are resistant to antibiotics, devastating the world population and causing a global collapse of civilization.<ref>[http://www.pasteur.fr/actu/presse/press/07pesteTIGR_E.htm Researchers sound the alarm: the multidrug resistance of the plague bacillus could spread]</ref>
; [[Shutdown of thermohaline circulation|Gulf Stream shutdown]] : There is some speculation that [[global warming]] could, via a shutdown or slowdown of the thermohaline circulation, trigger localised cooling in the North Atlantic and lead to cooling in that region. This would affect in particular areas like [[Ireland]], the [[Nordic countries]], and [[United Kingdom|Britain]] that are warmed by the [[North Atlantic drift]].<ref>[http://www.gulfstreamshutdown.com/ Gulf Stream shutdown]</ref><ref>[http://news.mongabay.com/2005/1207-uiuc.html 45% chance Gulf Stream current will collapse by 2100 finds research]</ref>
; [[Demography]] : Demographic trends create a "baby bust" that threatens the order of civilization.<ref name="babybust">[[Phillip Longman]] [http://www.foreignaffairs.org/20040501faessay83307/phillip-longman/the-global-baby-bust.html "The Global Baby Bust"] in [[Foreign Affairs]] magazine.</ref>
; [[Mutual assured destruction]] : A full scale [[Nuclear war]] could kill billions, and the resulting [[nuclear winter]] would effectively crush any form of civilization.
; [[Dysgenics]] : The ideas of [[dysgenics]] suggest that the average individual in a civilization may eventually become weaker, because the most intelligent reproduce least leaving the population less able to perform higher functions.
; [[Finance]] : Markets fail worldwide, resulting in economic collapse: mass unemployment, rioting, famine, death, and cannibalism.{{Fact|date=February 2007}} (This scenario happened, [[Great Depression|to some extent]], in the [[1930s]] and [[1940s]], [[Causes of World War II|helping to cause a major war]] that has, so far, been the only [[Hiroshima and Nagasaki|war to involve nuclear weapons]]. That war (along with its [[Second Sino-Japanese War|its immediate precursor in Asia]]) also involved [[Nanjing massacre|major atrocities]] and [[Holocaust|genocide]]. Such a scenario, in an age of [[ICBM]]s and [[hydrogen bomb]]s, might be even worse in the future.)
; [[Overpopulation]] : Some scenarios of simultaneous ecological (food & water production) and economical (see f.e. below) collapses with overpopulation are presumed to lead to a global civil war, where the remaining habitable areas are destroyed by competing humans (so called '[[Mad Max]]'-scenario).
; [[Peak oil#Implications of a world peak|Peak oil]] : Oil becomes scarce before an economically viable replacement is devised, leading to global chaos and discomfort.<ref name="peakoil">[[James Howard Kunstler]] [http://www.rollingstone.com/news/story/_/id/7203633?rnd=1128183871020&has-player=true&version=6.0.12.1059 "The Long Emergency"], in [[Rolling Stone Magazine]]</ref>
; Experimental accident : The unlikely creation of a hypothetical [[gravitational singularity|microsingularity]] or exotic matter in particle acceleration experiments, or some unanticipated experimental accident, resulting in destruction of the planet or a large scale disaster. An (unrealised) example was that the first test of an atomic weapon might lead to ignition of the atmosphere and global destruction (see [[Trinity test]]).

==Fictional==
:''See main article [[Apocalyptic and post-apocalyptic fiction]]

==Historical futurist scenarios==
Every generation has faced its own fears of an unknown future; the historical record of prior end of civilization scenarios is plentiful. Some of these include the following.

Many [[fiction]]al (and [[non-fiction]]al) stories from the era of the [[Cold War]] were based on the belief that a [[nuclear war]] was inevitable, and that this would result in the destruction of all life on the planet Earth (see [[World War III in popular culture]]).

[[Sir Isaac Newton]] (1642-1727), who was involved in alchemy and many other things in addition to science and mathematics, studied old texts and surmised that the end of the world would happen no earlier than [[2060]], although he was reluctant to put an exact date on it.<ref>[http://www.isaac-newton.org/newton_2060.htm "Isaac Newton, the Apocalypse and 2060 A.D."], by Stephen D. Snobelen, University of King’s College, Halifax</ref>

Many mistakenly believe that the [[Maya civilization]]'s [[Maya calendar|Long Count calendar]] ends abruptly on [[December 21]] [[2012]]. This misconception is due to the Maya practice of using only five places in Long Count Calendar inscriptions. On some monuments the Maya calculated dates far into the past and future but there is no end of the world date. There will be a Piktun ending (a cycle of 13 144,000 day Bak'tuns) on December 21st, 2012. A Piktun marks the end of a 1,872,000 day or approximately 5125 year period and is a significant event in the Maya calendar.

==See also==
*[[Societal collapse]]
*[[Planetary Phase of Civilization]]
*[[Global warming]]
*[[Cradle of Humanity]]
*[[Mega Disasters]]

==Notes==
{{reflist|2}}

==References==
*Corey S. Powell (2000). [http://www.findarticles.com/p/articles/mi_m1511/is_10_21/ai_65368918 "Twenty ways the world could end suddenly"], ''[[Discover Magazine]]''
*[[Martin Rees]] (2004). ''[[Our Final Hour|OUR FINAL HOUR: A Scientist's warning: How Terror, Error, and Environmental Disaster Threaten Humankind's Future in This Century — On Earth and Beyond]]''. ISBN 0-465-06863-4
*[[Jean-Francois Rischard]] (2003). ''High Noon 20 Global Problems, 20 Years to Solve Them''. ISBN 0-465-07010-8
*[[Edward O. Wilson]] (2003). ''The Future of Life''. ISBN 0-679-76811-4

==Further reading==
*[[Derrick Jensen]] (2006) ''[[Endgame (Derrick Jensen books)|Endgame]]''. ISBN 1-58322-730-X
*[[Jared Diamond]] (2005). ''[[Collapse: How Societies Choose to Fail or Succeed]]''. ISBN 0-670-03337-5
*[[John Leslie (philosopher)|John Leslie]] (1996). ''The End of the World''. ISBN 0-415-14043-9

==External links==
*[http://abcnews.go.com/2020/story?id=2319986 Last Days On Earth] (TV documentary) ABC News 2-hour Special Edition of 20/20 on 7 real end-of-the-world scenarios (Wed. Aug 30 2006)
*[http://www.guardian.co.uk/life/feature/story/0,13026,1458536,00.html "What a way to go"] from ''[[The Guardian]]''. Ten scientists name the biggest danger to Earth and assesses the chances of it happening. April 14, 2005.
*[http://www.frankfuredi.com/articles/misanthropy-20060418.shtml "Confronting the New Misanthropy"], by [[Frank Furedi]] in ''[[Spiked (magazine)|Spiked]]'', April 18 2006
*[http://www.ted.com/index.php/talks/view/id/167 Ted.com (video) - Stephen Petranek: 10 ways the world could end]

{{Doomsday}}

[[Category:Futurology]]
[[Category:Emergency management]]
[[Category:Hazards]]

[[es:Fin de la civilización]]
[[fi:Maailmanloppu]]

Globales existenzielles Risiko

2008-02-23T11:45:40Z

88.195.46.112: /* Humanity */

:''This is about the future of civilization, humans and the earth. For past civilizations, see [[societal collapse]].''
'''Risks to civilization, humans and planet Earth''' are [[existential risk]]s that would imperil mankind as a whole and/or have major adverse consequences for the course of human [[civilization]], [[human extinction]] or even the [[end of planet Earth]].<ref name="types">{{cite journal| authorlink=Nick Bostrom| first=Nick| last=Bostrom| year=2001| url=http://www.nickbostrom.com/existential/risks.html| title=Existential Risks: Analyzing Human Extinction Scenarios and Related Hazards| journal=Journal of Evolution and Technology| volume=9| month=March| year=2002}}</ref> The concept finds expression in various [[idiom|idiomatic]], phrases such as "[[End of the World]]", "[[Doomsday]]", "[[wikt:TEOTWAWKI|TEOTWAWKI]]", "TEOCAWKI" and others. 

==Types of risks==

Various risks exist for [[humanity]], but not all risks are equal. Risks can be roughly categorized into six types based on the scope of the risk (Personal, Regional, Global) and the intensity of the risk (Endurable or Terminal). This chart provides some examples.

{| border="1" cellspacing="0" cellpadding="2" class="wikitable"
!colspan="3" align="center"|'''Typology of risk''' <ref name="types" />
|-
!
!Endurable
!Terminal
|-
|'''Global'''
|Thinning of the ozone layer
|Global nuclear war
|-
|'''Regional'''
|Economic recession
|Genocide
|-
|'''Personal'''
|Theft of car
|Terminal illness
|}

The risks discussed in this article are those in the Global-Terminal category. This type of risk is one where an adverse outcome would either annihilate intelligent life, or permanently and drastically curtail its potential. For an alternative classification system see [[Jamais Cascio]]'s [http://www.openthefuture.com/2006/12/an_eschatological_taxonomy.html An Eschatological Taxonomy]. A problem for this system is the sheer size of humanity; even in the event of catastrophic nuclear war, total collapse of the ice sheets or ocean currents, or the rise of a devastating epidemic, it is extremely likely that some people will survive, though conventional civilization may collapse.

==Future scenarios==

There are many scenarios that have been suggested that could happen in the future. Some are certain to happen and will almost certainly end humanity, but may only happen on a very long timescale, or may happen sooner. Others are likely to happen on a shorter timescale, but will probably not completely destroy civilization. Still others are extremely unlikely, and may even be impossible. For example, [[Nick Bostrom]] writes:<ref name="unlikely">Nick Bostrom, section 4.7.</ref>
:''Some foreseen hazards (hence not members of the current category) which have been excluded from the list of bangs on grounds that they seem too unlikely to cause a global terminal disaster are: solar flares, supernovae, black hole explosions or mergers, gamma-ray bursts, galactic center outbursts, supervolcanoes, buildup of air pollution, gradual loss of human fertility, and various religious doomsday scenarios.''

===Space===

It is certain that events in space can cause [[life on Earth]] to come to an end. The certain events, however, will happen at an extremely long timescale measured in billions of years. Projections indicate that the [[Andromeda Galaxy]] is on a collision course with the Milky Way. Impact is predicted in about 3 billion years, and so Andromeda will approach at an average speed of about 140 kilometres (87 miles) per second; the two galaxies will probably merge to form a giant elliptical. This merging could eject the solar system in a more eccentric orbit{{Fact|date=February 2007}} and an unwanted position in the merged galaxy causing our planet to become uninhabitable (an actual collision is unnecessary). In about 5 billion years, [[stellar evolution]] predicts our [[sun]] will exhaust its core hydrogen and become a [[red giant]]. In so doing, it will become thousands of times more luminous.<ref>[http://hyperphysics.phy-astr.gsu.edu/hbase/astro/redgia.html Red Giants]</ref> Even in its current phase of stellar evolution, the sun is increasing in luminosity (at a very slow rate). Many scientists predict that in fewer than one billion years, the runaway [[greenhouse effect]] will make Earth unsuitable for life.{{Fact|date=October 2007}}

On an even longer time scale, the [[ultimate fate of the universe|universe may come to an end]]. The current [[age of the universe]] is estimated as being 13.7 billion years old. There are several competing theories as to the nature of our [[universe]] and how it will end, but in all cases, there will be no life possible. These scenarios take place on a considerably longer timescale than the expansion of the sun.

==== Meteorite impact ====

In the [[history of the Earth]], it is widely accepted that several large [[meteorite]]s have hit [[Earth]]. The [[Cretaceous-Tertiary extinction event|Cretaceous-Tertiary asteroid]], for example, is theorized to have caused the extinction of the [[dinosaur]]s. If such an object struck Earth it could have a serious impact on civilization. It's even possible that humanity would be completely destroyed: for this, the asteroid would need to be at least 1 km (0.6 miles) in diameter, but probably between 3–10 km (2–6 miles).<ref name="meteor">Nick Bostrom, section 4.10</ref> Asteroids with a 1 km diameter impact the Earth every 0.5 million years<ref name="meteor" /> on average. Larger asteroids are less common. The last large (>10 km) impact happened [[Cretaceous-Tertiary extinction event|65 million years ago]]. So-called [[Near-Earth asteroid]]s are regularly being observed.

Some scientists believe there are patterns in the number of meteorites hitting Earth. An interesting explanation of such a pattern is given by the hypothetical star [[Nemesis (star)|Nemesis]]. This hypothesis states that a star named Nemesis regularly passes through a denser part of the [[Oort cloud]], causing meteorite rains to collide onto Earth. However, the very existence of this pattern is not widely accepted, and the existence of the Nemesis star is highly contested.

A star passage that will cause an increase of meteorites is the arrival of a star called [[Gliese 710]]. This star is probably moving on a collision course with the [[Solar System]] and will likely be at a distance 1.1 [[light year]]s from the Sun in 1.4 million years. Some models predict that this will send large amounts of comets from the [[Oort cloud]] to the Earth.<ref>[http://www.exitmundi.nl/Gliese710.htm Date With The Neigbors: Gliese 710 And Other Incoming Stars]</ref> Other models, such as the one by García-Sánchez, predict an increase of only 5%.

==== Less likely cosmic threats ====






A number of other scenarios have been suggested. Massive objects, e.g., a [[star]], large [[planet]] or [[black hole]], could be catastrophic if a close encounter occurred in the solar system. Another threat might come from [[Gamma ray bursts#Mass extinction on Earth|gamma ray bursts]]; some scientists believe this may have caused mass extinction 450 million years ago.<ref name="gammaray">[http://www.nasa.gov/vision/universe/starsgalaxies/gammaray_extinction.html Explosions in Space May Have Initiated Ancient Extinction on Earth], [[NASA]].</ref> Both are very unlikely.<ref name="unlikely" /> Still others see [[extraterrestrial life]] as a possible threat to mankind;<ref name="aliens">[http://www.findarticles.com/p/articles/mi_m1511/is_10_21/ai_65368918 Twenty ways the world could end suddenly], Discover Magazine</ref> although alien life has never been found, scientists such as [[Carl Sagan]] have postulated that the existence of extraterrestrial life is very likely. In 1969, the "[[Extra-Terrestrial Exposure Law]]" was added to the Code of Federal Regulations (Title 14, Section 1211) in response to the possibility of biological contamination resulting from the US Apollo Space Program. It was removed in 1991.<ref>[http://www.snopes.com/legal/et.htm Urban Legends Reference Pages: Legal Affairs (E.T. Make Bail)]</ref> Scientists consider such a scenario technically possible, but unlikely.<ref name="aliensunlikely">Nick Bostrom, section 7.2.</ref>

===Earth===

In the history of the Earth, many [[ice age]]s have occurred. More ice ages will almost certainly come at an interval of 40,000–100,000 years. This would have a serious impact on civilization, because vast areas of land (mainly in [[North-America]], [[Europe]], and [[Asia]]) could become uninhabitable. It would still be possible to live in the tropical regions, but with possible loss of humidity/water. Currently, the world is technically existing in a warm period between such ice ages (the last ending c. 10000 years ago), and all civilizations (save a few hunter-gatherer populations) have come into existence within that time.

A less predictable scenario is a global [[pandemic]]. For example, if [[HIV]] mutates and becomes as transmissible as the [[common cold]], the consequences would be disastrous, but probably not fatal to the human species,<ref name="pandemic">Nick Bostrom, section 4.9.</ref> as some people are immune to HIV.<ref>[http://www.pbs.org/wgbh/evolution/library/10/4/l_104_06.html Evolution: Library: HIV Immunity]</ref> This particular scenario would also contradict the observable tendency for pathogens to become less fatal over time as a function of [[natural selection]]. A pathogen that quickly kills its hosts will not likely have enough time to spread to new ones, while one that kills its hosts more slowly or not at all will allow carriers more time to spread the infection, and thus likely outcompete a more lethal species or strain. A real-life example of this process can be found in the historical evolution of [[syphilis]] towards [http://www.qmul.ac.uk/news/newsrelease.php?news_id=9 a less virulent form]. Also as a virus mutates in a direction of being easily transmittable it will likely give up much of its virulence in the process. Though this is not to say that a highly destructive and highly transmissible disease is not possible. Of course, a pandemic resulting in human extinction need not arise naturally; the possibility of one caused by a deliberately-engineered pathogen cannot be ruled out.

Another possibility is the [[megatsunami]]. A megatsunami could, for example, destroy the entire east coast of the [[USA|United States of America]] (see [[La Palma]]). The coastal areas of the entire world could be flooded in case of the collapse of the [[West Antarctic Ice Sheet]].<ref name="wais">[http://igloo.gsfc.nasa.gov/wais/ US West Antarctice Ice Sheet initiative]</ref> While none of these scenarios could possibly destroy humanity completely, they could regionally threaten civilization.

An [[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 of these scenarios involve one or more of the following: [[Holocene extinction event]], [[Water crisis|scarcity of water]] that could lead to approximately one half of the Earth's population being without safe [[drinking water]], [[pollinator decline]], [[overfishing]], massive [[deforestation]], [[desertification]], [[climate change]], or massive [[water pollution]] episodes. A very recent 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]].

The 20th century has seen a rapid increase in [[human population]] due to [[History of medicine#Modern medicine|medical advances]] and massive increase in agricultural productivity<ref>[http://news.bbc.co.uk/1/hi/world/south_asia/4994590.stm BBC NEWS | The end of India's green revolution?]</ref> made by the [[Green Revolution]].<ref>[http://www.foodfirst.org/media/opeds/2000/4-greenrev.html Food First/Institute for Food and Development Policy]</ref> 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]]. The energy for the Green Revolution was provided by fossil fuels in the form of [[fertilizers]] (natural gas), [[pesticides]] (oil), and [[hydrocarbon]] fueled [[irrigation]].<ref>[http://wolf.readinglitho.co.uk/mainpages/agriculture.html How peak oil could lead to starvation]</ref> 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 theirs study ''Food, Land, Population and the U.S. Economy'' the maximum [[U.S. population]] for a [[sustainability|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 study.<ref>[http://www.energybulletin.net/281.html Eating Fossil Fuels | EnergyBulletin.net]</ref>

The authors of this study believe that the mentioned agricultural crisis will only begin to impact us after 2020, and will not become critical until 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.<ref>[http://www.soilassociation.org/peakoil Peak Oil: the threat to our food security]</ref><ref>[http://europe.theoildrum.com/node/2225 Agriculture Meets Peak Oil]</ref>

An abrupt [[Pole shift theory|reorientation of Earth's axis of rotation]] could cause a new [[extinction event]].<ref>{{cite web | url=http://www.nytimes.com/2006/10/12/science/earth/12extinct.html?ex=1176609600&en=9fc4a5a53674ca70&ei=5087&excamp=mkt_at8 | title=Study Links Extinction Cycles to Changes in Earth’s Orbit and Tilt | publication=[[The New York Times]] |date=2006-10-12 | author=Wilford, John Noble}}</ref>


When the [[supervolcano]] at [[Yellowstone National Park|Yellowstone]] last erupted, 600,000 years ago, the magma and ash covered roughly all of the area of North America west of the Mississippi river. Another such eruption could threaten civilization. Such an eruption could also release large amounts of gases that could alter the balance of the planet's carbon dioxide and cause a runaway greenhouse effect, or enough pyroclastic debris and other material may be thrown into the atmosphere to partially block out the sun and cause a natural [[nuclear winter]], similar to 1816, the [[Year Without A Summer]]. Such an eruption may cause the death of millions several hundred miles from the epicenter and overall hundreds of millions of deaths worldwide due to the failure of the [[monsoon]], causing starvation on an unthinkable scale.

Overall, '''Earth will be rendered lifeless once the Sun expands''' due to it running out of energy; the oceans will evaporate, and after the Sun shrinks, Earth will be too frigid to sustain life.


===Humanity===

Some threats for humanity come from humanity itself. The scenario that has been explored most is a [[nuclear warfare#current concerns|nuclear war]] or [[Doomsday device|another weapon]] with similar possibilities. It is difficult to predict whether it would exterminate humanity, but very certainly could alter civilization, in particular if there was a [[nuclear winter]] event.<ref name="nuclearwinter">Nick Bostrom, section 4.2.</ref>

Another category of disasters are [[technological singularity|unforeseen consequences of technology]].
It has been suggested that [[Artificial Intelligence#Hypothetical consequences of AI|learning computers]] take unforeseen actions or that [[Robot#possible dangers|robots]] would out-compete humanity.<ref name="billjoy">[[Bill Joy]], [http://www.wired.com/wired/archive/8.04/joy_pr.html Why the future doesn't need us]. In:[[Wired magazine|Wired]] magazine. See also [[technological singularity]].</ref>
[[Biotechnology]] could lead to the creation of a [[pandemic]], [[Nanotechnology]] could lead to [[grey goo]] - in both cases, either deliberately or by accident.<ref name="drexler">[[Eric Drexler]], [[Engines of Creation]], ISBN 0-385-19973-2, [http://www.foresight.org/EOC/ available online]</ref>
It has also been suggested that physical scientists might accidentally create a device that could destroy the earth and the solar system.<ref name="physicsaccident">Nick Bostrum, section 4.8</ref> In [[string theory]], there are some unknown variables. If those turn out to have an unfortunate value, the universe may not be stable and alter completely, destroying everything in it,<ref name="quantumtunneling">Malcolm Perry, ''Quantum Tunneling towards an exploding Universe?'' in: [[Nature]], [[24 April]] [[1986]]. [http://www.uhh.hawaii.edu/~dixon/quantum_tunneling.pdf available online].</ref> either at random or by an accidental experiment. This is called [[Quantum Vacuum Collapse]] by some.<ref name="qvc">[http://www.exitmundi.nl/vacuum.htm The day the Quantum Vacuum Collapsed]</ref> Another kind of accident is the ''[[Ice-9 Type Transition]]'', in which our planet including everything on it becomes a strange matter planet in a chain reaction. Some do not view this as a credible scenario.<ref name="ice9">Frank Wilczek, in an e-mail, [http://lists.nau.edu/cgi-bin/wa?A2=ind9907&L=phys-l&F=&S=&P=29937| This available online].</ref>

It has been suggested that runaway [[global warming]] might cause the climate on Earth to become like [[Venus]], which would make it uninhabitable. In less extreme scenarios it could cause the end of civilization.<ref name="runaway">Isaac M. Held, Brian J. Soden, ''Water Vapor Feedback and Global Warming'', In: Annu. Rev. Energy Environ 2000. [http://www.gfdl.noaa.gov/~gth/netscape/2000/annrev00.pdf available online]. Page 449.</ref> According to a UN climate report, the [[Himalayas|Himalayan]] glaciers that are the sources of [[Asia]]'s biggest rivers - [[Ganges]], [[Indus]], [[Brahmaputra]], [[Yangtze]], [[Mekong]], [[Salween]] and [[Yellow]] - could disappear by 2035 as temperatures rise.<ref>[http://www.planetark.com/dailynewsstory.cfm/newsid/42387/story.htm Vanishing Himalayan Glaciers Threaten a Billion]</ref> Approximately 2.4 billion people live in the [[drainage basin]] of the Himalayan rivers.<ref>[http://www.peopleandplanet.net/pdoc.php?id=3024 Big melt threatens millions, says UN]</ref> [[India]], [[China]], [[Pakistan]], [[Bangladesh]], [[Nepal]] and [[Myanmar]] could experience floods followed by [[droughts]] in coming decades. In [[India]] alone, the Ganges provides water for drinking and farming for more than 500 million people.<ref>[http://www.rediff.com/news/2007/jul/24indus.htm Ganges, Indus may not survive: climatologists]</ref><ref>[http://english.peopledaily.com.cn/90001/90781/90879/6222327.html Glaciers melting at alarming speed]</ref><ref>[http://news.bbc.co.uk/2/hi/science/nature/3998967.stm Himalaya glaciers melt unnoticed]</ref>

In [[Africa]], if current trends of soil degradation continue, the continent might
be able to feed just 25% of its population by 2025, according to [[United Nations University|UNU]]'s Ghana-based Institute for Natural Resources in Africa.<ref>[http://news.mongabay.com/2006/1214-unu.html Africa may be able to feed only 25% of its population by 2025]</ref>

[[James Lovelock]], creator of the [[Gaia hypothesis]], in his book ''[[The Revenge of Gaia]]'' (2006), has suggested that the elimination of [[rain forest]]s, and the falling planetary [[biodiversity]] is removing the [[homeostasis|homeostatic]] [[negative feedback]] mechanisms that maintain climate stability by reducing the effects of [[greenhouse gas]] emissions (particularly [[carbon dioxide]]). With the heating of the oceans, the extension of the [[thermocline]] layer into [[Arctic]] and [[Antarctic]] waters is preventing the overturning and nutrient enrichment necessary for [[algal blooms]] of [[phytoplankton]] on which the [[ecosystem]]s of these areas depend. With the loss of phytoplankton and tropical rain forests, two of the main [[carbon dioxide sink]]s for reducing [[global warming]], he suggests a runaway [[positive feedback]] effect could cause tropical [[desert]]s to cover most of the worlds tropical regions, and the disappearance of polar ice caps, posing a serious challenge to global civilization.

Using [[scenario analysis]], the [[Global scenario group]] (GSG), a coalition of international scientists convened by [[Paul Raskin]], developed a series of possible futures for the world as it enters a [[Planetary Phase of Civilization]]. One scenario involves the complete breakdown of civilization as the effects of [[climate change]] become more pronounced, competition for scarce resources increases, and the rift between the poor and the wealthy widens. The GSG’s other scenarios, such as [[Policy Reform]], [[Eco-Communalism]], and [[Great Transition]] avoid this societal collapse and eventually result in environmental and social [[sustainability]]. They claim the outcome is dependent on human choice<ref>[http://www.gtinitiative.org/documents/PDFFINALS/16WorldLines.pdf World Lines: Pathways, Pivots, and the Global Future]. [[Paul Raskin]]. 2006. Boston:[http://www.tellus.org Tellus Institute] </ref> and the possible formation of a [[global citizens movement]] which could influence the trajectory of global development.<ref> [http://www.gtinitiative.org/documents/PDFFINALS/15Movements.pdf Dawn of the Cosmopolitan: The Hope of a Global Citizens Movement] Orion Kriegman. 2006. Boston:[http://www.tellus.org Tellus Institute]</ref>

Other scenarios that have been named are:

; [[Antibiotic resistance]] : Natural selection would create super bacteria that are resistant to antibiotics, devastating the world population and causing a global collapse of civilization.<ref>[http://www.pasteur.fr/actu/presse/press/07pesteTIGR_E.htm Researchers sound the alarm: the multidrug resistance of the plague bacillus could spread]</ref>
; [[Shutdown of thermohaline circulation|Gulf Stream shutdown]] : There is some speculation that [[global warming]] could, via a shutdown or slowdown of the thermohaline circulation, trigger localised cooling in the North Atlantic and lead to cooling in that region. This would affect in particular areas like [[Ireland]], the [[Nordic countries]], and [[United Kingdom|Britain]] that are warmed by the [[North Atlantic drift]].<ref>[http://www.gulfstreamshutdown.com/ Gulf Stream shutdown]</ref><ref>[http://news.mongabay.com/2005/1207-uiuc.html 45% chance Gulf Stream current will collapse by 2100 finds research]</ref>
; [[Demography]] : Demographic trends create a "baby bust" that threatens the order of civilization.<ref name="babybust">[[Phillip Longman]] [http://www.foreignaffairs.org/20040501faessay83307/phillip-longman/the-global-baby-bust.html "The Global Baby Bust"] in [[Foreign Affairs]] magazine.</ref>
; [[Mutual assured destruction]] : A full scale [[Nuclear war]] could kill billions, and the resulting [[nuclear winter]] would effectively crush any form of civilization.
; [[Dysgenics]] : The ideas of [[dysgenics]] suggest that the average individual in a civilization may eventually become weaker, because the most intelligent reproduce least leaving the population less able to perform higher functions.
; [[Finance]] : Markets fail worldwide, resulting in economic collapse: mass unemployment, rioting, famine, death, and cannibalism.{{Fact|date=February 2007}} (This scenario happened, [[Great Depression|to some extent]], in the [[1930s]] and [[1940s]], [[Causes of World War II|helping to cause a major war]] that has, so far, been the only [[Hiroshima and Nagasaki|war to involve nuclear weapons]]. That war (along with its [[Second Sino-Japanese War|its immediate precursor in Asia]]) also involved [[Nanjing massacre|major atrocities]] and [[Holocaust|genocide]]. Such a scenario, in an age of [[ICBM]]s and [[hydrogen bomb]]s, might be even worse in the future.)
; [[Overpopulation]] : Some scenarios of simultaneous ecological (food & water production) and economical (see f.e. below) collapses with overpopulation are presumed to lead to a global civil war, where the remaining habitable areas are destroyed by competing humans (so called '[[Mad Max]]'-scenario).
; [[Peak oil#Implications of a world peak|Peak oil]] : Oil becomes scarce before an economically viable replacement is devised, leading to global chaos and discomfort.<ref name="peakoil">[[James Howard Kunstler]] [http://www.rollingstone.com/news/story/_/id/7203633?rnd=1128183871020&has-player=true&version=6.0.12.1059 "The Long Emergency"], in [[Rolling Stone Magazine]]</ref>
; Experimental accident : The unlikely creation of a hypothetical [[gravitational singularity|microsingularity]] or exotic matter in particle acceleration experiments, or some unanticipated experimental accident, resulting in destruction of the planet or a large scale disaster. An (unrealised) example was that the first test of an atomic weapon might lead to ignition of the atmosphere and global destruction (see [[Trinity test]]).
;[[World War III]] : There's no reason to believe that this threat has been passed.

==Fictional==
:''See main article [[Apocalyptic and post-apocalyptic fiction]]

==Historical futurist scenarios==
Every generation has faced its own fears of an unknown future; the historical record of prior end of civilization scenarios is plentiful. Some of these include the following.

Many [[fiction]]al (and [[non-fiction]]al) stories from the era of the [[Cold War]] were based on the belief that a [[nuclear war]] was inevitable, and that this would result in the destruction of all life on the planet Earth (see [[World War III in popular culture]]).

[[Sir Isaac Newton]] (1642-1727), who was involved in alchemy and many other things in addition to science and mathematics, studied old texts and surmised that the end of the world would happen no earlier than [[2060]], although he was reluctant to put an exact date on it.<ref>[http://www.isaac-newton.org/newton_2060.htm "Isaac Newton, the Apocalypse and 2060 A.D."], by Stephen D. Snobelen, University of King’s College, Halifax</ref>

Many mistakenly believe that the [[Maya civilization]]'s [[Maya calendar|Long Count calendar]] ends abruptly on [[December 21]] [[2012]]. This misconception is due to the Maya practice of using only five places in Long Count Calendar inscriptions. On some monuments the Maya calculated dates far into the past and future but there is no end of the world date. There will be a Piktun ending (a cycle of 13 144,000 day Bak'tuns) on December 21st, 2012. A Piktun marks the end of a 1,872,000 day or approximately 5125 year period and is a significant event in the Maya calendar.

==See also==
*[[Societal collapse]]
*[[Planetary Phase of Civilization]]
*[[Global warming]]
*[[Cradle of Humanity]]
*[[Mega Disasters]]

==Notes==
{{reflist|2}}

==References==
*Corey S. Powell (2000). [http://www.findarticles.com/p/articles/mi_m1511/is_10_21/ai_65368918 "Twenty ways the world could end suddenly"], ''[[Discover Magazine]]''
*[[Martin Rees]] (2004). ''[[Our Final Hour|OUR FINAL HOUR: A Scientist's warning: How Terror, Error, and Environmental Disaster Threaten Humankind's Future in This Century — On Earth and Beyond]]''. ISBN 0-465-06863-4
*[[Jean-Francois Rischard]] (2003). ''High Noon 20 Global Problems, 20 Years to Solve Them''. ISBN 0-465-07010-8
*[[Edward O. Wilson]] (2003). ''The Future of Life''. ISBN 0-679-76811-4

==Further reading==
*[[Derrick Jensen]] (2006) ''[[Endgame (Derrick Jensen books)|Endgame]]''. ISBN 1-58322-730-X
*[[Jared Diamond]] (2005). ''[[Collapse: How Societies Choose to Fail or Succeed]]''. ISBN 0-670-03337-5
*[[John Leslie (philosopher)|John Leslie]] (1996). ''The End of the World''. ISBN 0-415-14043-9

==External links==
*[http://abcnews.go.com/2020/story?id=2319986 Last Days On Earth] (TV documentary) ABC News 2-hour Special Edition of 20/20 on 7 real end-of-the-world scenarios (Wed. Aug 30 2006)
*[http://www.guardian.co.uk/life/feature/story/0,13026,1458536,00.html "What a way to go"] from ''[[The Guardian]]''. Ten scientists name the biggest danger to Earth and assesses the chances of it happening. April 14, 2005.
*[http://www.frankfuredi.com/articles/misanthropy-20060418.shtml "Confronting the New Misanthropy"], by [[Frank Furedi]] in ''[[Spiked (magazine)|Spiked]]'', April 18 2006
*[http://www.ted.com/index.php/talks/view/id/167 Ted.com (video) - Stephen Petranek: 10 ways the world could end]

{{Doomsday}}

[[Category:Futurology]]
[[Category:Emergency management]]
[[Category:Hazards]]

[[es:Fin de la civilización]]
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