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.
Types of risks
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 |
Cancer/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.
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 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 "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, supervolcanos, loss of biodiversity, buildup
of air pollution, gradual loss of human fertility, and various religious
doomsday scenarios."
Space
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 per second(86.9918 miles per second); the
two galaxies will probably merge to form a giant elliptical. This merging
will most likely either eject our solar system into deep space or bombard
it with other solar systems, either way causing our planet to become uninhabitable
(an actual collision is unnecessary). In 5 to 6 billion years, stellar evolution
predicts our sun will evolve in a red giant and will probably completely
envelope the earth. This will occur as long as the sun's gravity, which
will reduce over time as it radiates its mass away, is still able to keep
Earth in a close enough orbit. Even if the Earth does move out to a more
distant orbit, there may not be enough energy to sustain life since the
effective temperature of a red giant decreases (radiates less heat) as it
grows in size. Besides the red giant option, there are some astronomers
who believe that the sun is currently increasing in luminosty (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 an even longer timescale than the expanding of the sun.
Meteorites
In the history of the Earth, it is widely accepted that several large
meteorites have hit Earth. One is theorized to have caused the extinction
of the dinosaurs. If a large meteorite hit 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 (.62137
miles) in diameter, but probably between 3–10 km (1.86411-6.2137 miles) .
Asteroids with 1 km in diameter impact the Earth every 0.5 million years
on average. Larger asteroids are more rare. The last large 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. A possible explanation of such a pattern is given by
the hypothetical Nemesis star. There is a theory stating that this 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.
Another scenario that might 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. 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 at one time sterilized items returning from space to kill
any potential "alien" bugs that might threaten humanity. Scientists consider
such a scenario technically possible, but unlikely.
Earth
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 fatal, 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 possibilities is the megatsunami. A megatsunami could, for example,
destroy the entire east coast of the United States of America. 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, 74,000 years ago,
the magma 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:
-
Antibiotic resistance. Natural selection would create super bacteria
that are resistant to antibiotics, devastating the world population and causing
a global collapse of civilization.
-
Catastrophe theory predicts a software-complexity tipping point when
the integrated world becomes vulnerable to disastrous bugs in the system.
-
Demography. Demographic trends create a "baby bust" that threatens the
order of civilization as we know it.
-
Dysgenics. A lack of natural selection and the tendency of the more
intelligent to have fewer children would lower the average health and intelligence
enough to lead to an eventual collapse of civilization.
-
Ecology. Natural resources are used up, or the environment is so damaged
through pollution and destruction that civilization fails.
-
Finance. Markets fail worldwide, resulting in economic collapse: mass
unemployment, rioting, famine, and death.
-
Infertility. Human fertility continues to decline, eventually ending
with no fertile humans left to continue the species.
-
Insanity. Mass insanity.
-
Peak oil. Oil runs out before an economically viable replacement is
devised, leading to global chaos.
-
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.
-
World government. Misguided world government caps progress, leading
to stagnation and reversals of Civilization.
Historical
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:
- 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. Despite this, some people also believe
according to Nostradamus, that the world will end in the year 3797. No explanation
of how is given.
- The
Y2K bug, which was supposed to wreak havoc on computer systems and disrupt
life as we know it. See also Millennialism.
- The
Maya civilization's long count calendar ends abruptly on 21 December (or
23 December) 2012. Many people have inexplicably taken this as a sign that
the world will end though it is not known if the Mayans believed this.
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