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Global catastrophic risk

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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 risks 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. The concept finds expression in various idiomatic phrases such as "End of the World", "Doomsday", "TEOTWAWKI" 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.

Typology of risk
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 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:

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 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. 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.

On an even longer time scale, the universe may come to an end. The current age of the universe is estimated as being 13.8 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 meteorites have hit Earth. The Cretaceous-Tertiary asteroid, for example, is theorized to have caused the extinction of the dinosaurs. If such an object struck the 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). Asteroids with a 1 km diameter impact the Earth every 0.5 million years on average. Larger asteroids are less common. The last large (>10 km) impact happened 65 million years ago. So-called Near-Earth asteroids 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. 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 years 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. 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; some scientists believe this may have caused mass extinction 450 million years ago. Both are very unlikely. Still others see extraterrestrial life as a possible threat to mankind; 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. Scientists consider such a scenario technically possible, but unlikely.

Earth

In the history of the Earth, many ice ages 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 as we know it today, 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, we technically exist in a warm period between such ice ages (the last ending c. 10000 years ago), and all civilization save a few hunter-gatherer populations has 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, as some people are immune to HIV. 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 a less virulent form. However, this idea is debated, see selfish gene. 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 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. While none of these scenarios could possibly destroy humanity completely, they could regionally threaten civilization as we know it.

However, the most likely scenario is via an ecological disaster, such as world crop failure and collapse of ecosystem services that could be induced by the present trends of overpopulation and non-sustainable agriculture. Most of these scenarios involve one or more of the following: Holocene extinction event, 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 or massive water pollution episode. A very recent threat in this direction is the Colony Collapse Disorder, a phenomenon that might foreshadow the imminent extinction of the Western Honey Bee. As the bee plays a vital role in pollination, its extinction would severely disrupt the food chain.

The 20th century have seen a rapid increase in human population due to medical advances and massive increase in agricultural productivity made by 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. 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 theirs 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 study.

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. The oncoming peaking of global oil production (and subsequent decline of production), along with the peak of North American natural gas production will very likely precipitate this agricultural crisis much sooner than expected. 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.

An abrupt reorientation of Earth's axis of rotation could cause a new extinction event.

When the supervolcano at 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.

Humanity

Some threats for humanity come from humanity itself. The scenario that has been explored most is a nuclear war or another weapon with similar possibilities. It is difficult to predict whether it would exterminate humanity, but very certainly could alter civilization as we know it, in particular if there was a nuclear winter event.

Another category of disasters are unforeseen consequences of technology. It has been suggested that learning computers take unforeseen actions or that robots would out-compete humanity. Biotechnology could lead to the creation of a pandemic, Nanotechnology could lead to grey goo - in both cases, either deliberately or by accident. It has also been suggested that physical scientists might accidentally create a device that could destroy the earth and the solar system. 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, either at random or by an accidental experiment. This is called Quantum Vacuum Collapse by some. 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.

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 as we know it.

James Lovelock, creator of the Gaia hypothesis, in his book The Revenge of Gaia (2006), has suggested that the elimination of rain forests, and the falling planetary biodiversity is removing the 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 ecosystems of these areas depend. With the loss of phytoplankton and tropical rain forests, two of the main carbon dioxide sinks for reducing global warming, he suggests a runaway positive feedback effect could cause tropical deserts 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 and the possible formation of a global citizens movement which could influence the trajectory of global development.

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.
Demography
Demographic trends create a "baby bust" that threatens the order of civilization.
Mutual assured destruction
A full scale Nuclear war could kill billions, and the resulting Nuclear fallout would effectively crush any form of civilization.
Dysgenics
The theory of dysgenics suggests 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.
Overpopulation
World population may increase to such an extent in the future that it would lead to lack of space for habitation, except on the Moon and other planets.
Peak oil
Oil becomes scarce before an economically viable replacement is devised, leading to global chaos and discomfort.
Quantum energy
In the search for new quantum particles, scientists accidentally destroy the universe (or at the least, the Earth). This, however, is highly unlikely as far more powerful events occur in nature.
Telomere
Some researchers theorize a tiny loss of telomere length from one generation to the next, mirroring the process of aging in individuals. Over thousands of generations the telomere erodes down to its critical level. Once at the critical level we would expect to see outbreaks of age-related diseases occurring earlier in life and finally a population crash; however, this possibility may not result in extinction due to the self-reinforcing effects of natural selection.

Fictional

See main article Apocalyptic and post-apocalyptic science 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 fictional (and non-fictional) 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 for a list).

Nostradamus wrote a prediction that a great catastrophe would occur in the seventh month (July, or some argue September, the seventh month of the pre-modern calendar) of the year 1999. Many followers of his writings took this to mean that the end of the world would occur. When the chosen date came and went without incident, translators of his works began revising them with new interpretations of what the prediction actually meant. (Many now believe that this prediction referred to September 11, 2001.) Despite this, some people also believe according to Nostradamus, that the world will end in the year 3797. One leading Nostradamus scholar believes that is the year the Sun will explode as a Red Giant, possibly because of extraterrestrial intervention.

The Y2K bug was supposed to wreak havoc on computer systems. See also Millennialism.

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 be in 2060, although he was reluctant to put an exact date on it.

Many mistakenly believe that the Maya civilization's long count calendar ends abruptly on 21 December (or 23 December) 2012. This misconception is due to the Maya practice of abbreviating their dates to five decimal places. On monuments where the full date is shown the end of the last creation is said to happen much farther in the future; however, the Mayas did believe that there will be a baktun ending in 2012. A baktun marks the end of a 400 year period and was a significant event on the Maya calendar. In the Aztec calendar, 2012 marks the end of a 26,000 year planetary cycle. This cycle is known as the Great Year and most likely refers to the precession of the equinoxes.

Notes

  1. ^ Bostrom, Nick (2002). "Existential Risks: Analyzing Human Extinction Scenarios and Related Hazards". Journal of Evolution and Technology. 9. {{cite journal}}: Unknown parameter |month= ignored (help)
  2. ^ Nick Bostrom, section 4.7.
  3. Red Giants
  4. ^ Nick Bostrom, section 4.10
  5. http://www.exitmundi.nl/Gliese710.htm
  6. Explosions in Space May Have Initiated Ancient Extinction on Earth, NASA.
  7. Twenty ways the world could end suddenly, Discover Magazine
  8. Urban Legends Reference Pages: Legal Affairs (E.T. Make Bail)
  9. Nick Bostrom, section 7.2.
  10. Nick Bostrom, section 4.9.
  11. http://www.pbs.org/wgbh/evolution/library/10/4/l_104_06.html
  12. US West Antarctice Ice Sheet initiative
  13. BBC NEWS | The end of India's green revolution?
  14. Food First/Institute for Food and Development Policy
  15. How peak oil could lead to starvation
  16. Eating Fossil Fuels | EnergyBulletin.net
  17. Peak Oil: the threat to our food security
  18. Agriculture Meets Peak Oil
  19. Wilford, John Noble (2006-10-12). "Study Links Extinction Cycles to Changes in Earth's Orbit and Tilt". {{cite web}}: Unknown parameter |publication= ignored (help)
  20. Nick Bostrom, section 4.2.
  21. Bill Joy, Why the future doesn't need us. In:Wired magazine. See also technological singularity.
  22. Eric Drexler, Engines of Creation, ISBN 0-385-19973-2, available online
  23. Nick Bostrum, section 4.8
  24. Malcolm Perry, Quantum Tunneling towards an exploding Universe? in: Nature, 24 April 1986. available online.
  25. The day the Quantum Vacuum Collapsed
  26. Frank Wilczek, in an e-mail, This available online.
  27. Isaac M. Held, Brian J. Soden, Water Vapor Feedback and Global Warming, In: Annu. Rev. Energy Environ 2000. available online. Page 449.
  28. World Lines: Pathways, Pivots, and the Global Future. Paul Raskin. 2006. Boston:Tellus Institute
  29. Dawn of the Cosmopolitan: The Hope of a Global Citizens Movement Orion Kriegman. 2006. Boston:Tellus Institute
  30. Phillip Longman "The Global Baby Bust" in Foreign Affairs magazine.
  31. James Howard Kunstler "The Long Emergency", in Rolling Stone Magazine
  32. "What a way to go", The Guardian (April 14, 2005). See External links.
  33. "Isaac Newton, the Apocalypse and 2060 A.D.", by Stephen D. Snobelen, University of King’s College, Halifax

References

Further reading

See also

Global catastrophic risks
Technological
Sociological
Ecological
Climate change
Earth Overshoot Day
Biological
Extinction
Others
Astronomical
Eschatological
Others
Fictional
Organizations
General

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