The end of civilization or the end of the world are phrases used in reference to human extinction scenarios, doomsday events, and related hazards which occur on a global scale. These are risks that would imperil humankind as a whole and/or have major adverse consequences for the course of human civilization. The term existential risk is sometimes used in this context.
The prediction of future events is known as futures studies.
Various risks exist for mankind and civilization, 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 Ozone Layer | "End of civilization" |
| Regional | Economic recession | Genocide |
| Personal | House burns down | Death |
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.
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 will only happen on a very long timescale. 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 :
See also: Human extinction scenarios.
It is certain that events in space will 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 will most likely 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 6 to 7 billion years, stellar evolution predicts our sun will evolve into a red giant and will probably completely envelop the Earth. Because of a new process in the sun's core (fusion of helium besides a fusion of hydrogen) and radiation pressure, the sun's diameter will expand to nearly Venus orbit. Besides the red giant option, there are some astronomers who believe that the sun is currently increasing in luminosity (at a very slow rate), and they predict that in fewer than one billion years, the Earth will be too hot for life as we know it to survive, and have too much radiation as well.
On an even longer time scale, the universe will come to an end. The current age of the universe is estimated as being 13.7 billion years. 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 expanding of the sun.
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 more rare. 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 amount of meteorites hitting the earth. An interesting explanation of such a pattern is given by the hypothetical Nemesis star. 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 controversial.
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%.
A number of other scenarios have been suggested. A Black Hole could enter the solar system . If this happened, the result would be catastrophic. 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. Even NASA sterilizes items returning from space to kill any potential "alien" bugs that might threaten humanity. Scientists consider such a scenario technically possible, but unlikely.
In the history of the Earth, many ice ages have happened. 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 and Europe) would become uninhabitable. It would still be possible to live in the tropical regions.
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 natural function of biological pressure.
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.
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".
Probably the biggest threat for humanity comes 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.
Other scenarios that have been named are:
This article is licensed under the GNU Free Documentation License.
It uses material from the
"End of civilization".
Home Page • arts • business • computers • games • health • hospitals • home • kids & teens • news • physicians • recreation• reference • regional • science • shopping • society • sports • world