Ultimate Fate of the Human Race
Existential Risks that Could Threaten Humankind as a Whole



 
Ultimate Fate of the Human Race
Existential Risks that Could Threaten Humankind as a Whole


 
Risks to civilization, humans, and planet Earth are existential risks that could threaten humankind as a whole, have adverse consequences for the course of human civilization, or even cause the end of planet Earth. The concept is expressed in various phrases such as "End of the World".

Various risks exist for humanity, but not all are equal. Risks can be roughly categorized into six types based on the scope (personal, regional, global) and the intensity (endurable or terminal).

While there are many scenarios as to what may cause the end of the world, it is believed that humanity is the most likely category which may cause the final verdict for the human race.


Human extinction is the end of the human species. Various scenarios have been discussed in science, popular culture, and religion.

Humans are very widespread on the Earth, and live in communities which (whilst interconnected) are capable of some kind of basic survival in isolation.


Therefore, pandemic and deliberate killing aside, to achieve human extinction, the entire planet would have to be rendered uninhabitable.

This would typically be during a mass extinction event, a precedent of which exists in the Permian–Triassic extinction event among other examples.

In the near future, one anthropogenic extinction scenario exists: global nuclear annihilation; and two possible natural ones: bolide impact and large scale volcanism or other catastrophic climate change.

Both natural causes have occurred repeatedly in the geologic past and there is no reason to consider them unlikely in the future.

As technology develops, there is a possibility that humans may be deliberately destroyed by the actions of a rogue state or individual in a form of global suicide attack, but this is balanced by the possibility that technological advancement may resolve or prevent potential extinction scenarios.

Another scenario is the emergence of a pandemic of such virulence and infectiousness that very few humans survive the disease.

While not actually a human extinction event, this may leave only very small, very scattered human populations that would then evolve in isolation.

It is important to differentiate between human extinction and the extinction of all life on Earth.

Of possible extinction events, only a pandemic is selective enough to eliminate humanity while leaving the rest of complex life on earth relatively unscathed.


Attitudes to human extinction vary widely depending on beliefs concerning spiritual survival (souls, heaven, reincarnation, and so forth), the value of the human species, whether the human species evolves individually or collectively, and many other factors.

Many religions prophesy an "end times" to the universe. Human extinction is therefore a part of the faith of many humans to the extent that the end time means the absolute end of their physical humanity but perhaps not an eternal soul.

However not all faiths connect human extinction to the end times, since some believe in cyclical regeneration, or that end times actually means the beginning of a new kind of existence.



Humanity

"I don't know what weapons will be used in world war three, but in world war four people will use sticks and stones."

–– Albert Einstein


The fact that the vast majority of the species that have existed on Earth have become extinct, has led to the suggestion that all species have a finite lifespan and thus human extinction would be inevitable.

Dave Raup and Jack Sepkoski found for example a twenty-six-million-year periodicity in elevated extinction rates, caused by factors unknown.

Based upon evidence of past extinction rates Raup and others have suggested that the average longevity of an invertebrate species is between 4-6 million years, while that of vertebrates seems to be 2-4 million years.

The shorter period of survival for mammals lies in their position further up the food chain than many invertebrates, and therefore an increased liability to suffer the effects of environmental change.

A counter-argument to this is that humans are unique in their adaptive and technological capabilities, so it is not possible to draw reliable inferences about the probability of human extinction based on the past extinctions of other species. Certainly, the evidence collected by Raup and others suggested that generalist, geographically dispersed species, like humans, generally have a lower rate of extinction than those species that require a particular habitat.

In addition, the human species is probably the only species with a conscious prior knowledge of their own demise, and therefore would be likely to take steps to avoid it. Humans are very similar to other primates in their propensity towards intra-species violence; Jared Diamond's The Third Chimpanzee estimates that 64% of hunter-gather societies engage in warfare every two years.

Although it has been argued that warfare is a cultural artifact, many anthropologists dispute this, noting that small human tribes exhibit similar patterns of violence to chimpanzee groups, the most murderous of the primates, and one of two of our nearest living genetic relatives.

The "higher" functions of reason and speech are more developed in the brain of Homo sapiens than other primates, but the relative size of the limbic system is a constant in apes, monkeys, and humans. The combination of inventiveness and urge to violence in humans has been cited as evidence against its long term survival.



Meteorite Impact

"We have absolutely no way at this point in time to stop an object that's, lets hypothetically say, 900 kilometers in diameter and moving at 60,000 miles per second. Not gonna happen."

–– Branton Plaster, Wired.com


Earth has collided with several large asteroids in recent geological history. The Cretaceous-Tertiary asteroid, for example, is theorized to have caused the extinction of the dinosaurs 65 million years ago.

If such an object struck Earth it could have a serious impact on civilization.

It is even possible that humanity would be completely destroyed; for this to occur the asteroid would need to be at least 1 km (0.62 miles) in diameter, but probably between 3 and 10 km (2–6 miles).

Asteroids with a 1 km diameter have impacted the Earth on average once every 500,000 years.

Larger asteroids are less common. So-called Near-Earth asteroids are regularly being observed.1.4 million years from now the star Gliese 710 is expected to cause an increase in the number of meteoroids in the vicinity of Earth by passing within 1.1 light years of the Sun.

Some models predict that this will cause a large number of comets from the Oort cloud to impact Earth, whereas other models predict only a 5% increase in the rate of impact.



Massive Earthquake

Earthquakes that caused the greatest loss of life, while powerful, were deadly because of their proximity to either heavily populated areas or the ocean, where earthquakes often create tsunamis that can devastate communities thousands of kilometers away. Regions most at risk for great loss of life include those where earthquakes are relatively rare but powerful, and poor regions with lax, unenforced, or nonexistent seismic building codes.

One of the most devastating earthquakes in recorded history occurred on January 23rd, 1556 in the Shaanxi province, China, killing more than 830,000 people.

Most of the population in the area at the time lived in yaodongs, artificial caves in loess cliffs, many of which collapsed during the catastrophe with great loss of life.

The 1976 Tangshan earthquake, with death toll estimated to be between 240,000 to 655,000, is believed to be the largest earthquake of the 20th century by death toll.

The largest earthquake that has been measured on a seismograph reached 9.5 magnitude, occurring on May 22nd, 1960.

Its epicenter was near Cañete, Chile. The energy released was approximately twice that of the next most powerful earthquake, the Good Friday Earthquake, which was centered in Prince William Sound, Alaska. The ten largest recorded earthquakes have all been megathrust earthquakes; however, of these ten, only the 2004 Indian Ocean earthquake is simultaneously one of the deadliest earthquakes in history.

Earthquakes that caused the greatest loss of life, while powerful, were deadly because of their proximity to either heavily populated areas or the ocean, where earthquakes often create tsunamis that can devastate communities thousands of kilometers away. Regions most at risk for great loss of life include those where earthquakes are relatively rare but powerful, and poor regions with lax, unenforced, or nonexistent seismic building codes.



Climate Change

Global warming is the continuing rise in the average temperature of Earth's atmosphere and oceans. Global warming is caused by increased concentrations of greenhouse gases in the atmosphere, resulting from human activities such as deforestation and burning of fossil fuels. This finding is recognized by the national science academies of all the major industrialized countries and is not disputed by any scientific body of national or international standing.

Climate change is any long-term significant change in the expected patterns of average weather of a specific region (or, more relevantly to contemporary socio-political concerns, of the Earth as a whole) over an appropriately significant period of time.

Climate change reflects abnormal variations to the expected climate within the Earth's atmosphere and subsequent effects on other parts of the Earth, such as in the ice caps over durations ranging from decades to millions of years.

According to the UN’s Office for the Coordination of Humanitarian Affairs (OCHA), climate disasters are on the rise.

Around 70 percent of disasters are now climate related – up from around 50 percent from two decades ago. These disasters take a heavier human toll and come with a higher price tag.

In the last decade, 2.4 billion people were affected by climate related disasters, compared to 1.7 billion in the previous decade and the cost of responding to disasters has risen tenfold between 1992 and 2008.

Destructive sudden heavy rains, intense tropical storms, repeated flooding and droughts are likely to increase, as will the vulnerability of local communities in the absence of strong concerted action. Sea level rise may completely inundate certain areas.

In the history of the Earth, twelve ice ages have occurred. More ice ages will be possible at an interval of 40,000–100,000 years although engineers working for Posiva, a Finnish company involved in the underground storage of nuclear waste, have built their facility to withstand an Ice Age starting as 'soon' as 20,000 years.

An Ice Age 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 existing in an interglacial period within a much older glacial event. The last glacial expansion ended about 10,000 years ago, and all civilizations evolved later.



Supervolcano

When the supervolcano at Yellowstone last erupted 640,000 years ago, the magma and ash ejected from the caldera covered most of the United States west of the Mississippi river and part of northeastern Mexico. Another such eruption could threaten civilization.

A supervolcano is a volcano capable of producing a volcanic eruption with ejecta greater than 1,000 cubic kilometers (240 cubic miles).

This is thousands of times larger than most historic volcanic eruptions. Supervolcanoes can occur when magma in the Earth rises into the crust from a hotspot but is unable to break through the crust.

Pressure builds in a large and growing magma pool until the crust is unable to contain the pressure. They can also form at convergent plate boundaries (for example, Toba) and continental hotspot locations (for example, Yellowstone).

The Discovery Channel highlighted six known supervolcanoes: the Yellowstone, Long Valley, and Valles Caldera in the United States; Lake Toba, North Sumatra, Indonesia; Taupo Volcano, North Island, New Zealand; and Aira Caldera, Kagoshima Prefecture, Kyūshū, Japan.

Although there are only a handful of Quaternary supervolcanoes, supervolcanic eruptions typically cover huge areas with lava and volcanic ash and cause a long-lasting change to weather (such as the triggering of a small ice age) sufficient to threaten the extinction of species.

When the supervolcano at Yellowstone last erupted 640,000 years ago, the magma and ash ejected from the caldera covered most of the United States west of the Mississippi river and part of northeastern Mexico. 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 might be thrown into the atmosphere to partially block out the sun and cause a volcanic winter, as happened in 1816 following the eruption of Mount Tambora, the so-called Year Without a Summer.

Such an eruption might cause the immediate deaths of millions of people several hundred miles from the eruption, and perhaps billions of deaths worldwide due to the failure of the monsoon, as well as destruction of the "American breadbasket", causing starvation on a massive scale.

Supervolcanoes are more likely threats than many others, as a prehistoric Indonesian supervolcano eruption may have reduced the human population to only a few thousand individuals, while no catastrophic bolide impact, for example, has occurred since long before modern humans evolved.



Disease

A popular folk etymology holds that the children's game of "Ring Around the Rosy" is derived from the appearance of the bubonic plague. Proponents claim that "Ring around the rosy" refers to the rosy-red, rash-like ring that appeared as a symptom of the plague. "Pocket full of posy" referred to carrying flower petals as at the time it was believed the disease was spread through the ether of unhygene, and scent stopped the spread. "Ashes, ashes" referred to the burning of infected corpses, and "we all fall down" referred to the virulent deaths attributed to the plague.

A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs.

It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune diseases.

In humans, "disease" is often used more broadly to refer to any condition that causes pain, dysfunction, distress, social problems, and/or death to the person afflicted, or similar problems for those in contact with the person.

In this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections. Isolated symptoms, deviant behaviors, and atypical variations of structure and function, while in other contexts and for other purposes these may be considered distinguishable categories.

Diseases usually affect people not only physically, but also emotionally, as contracting and living with many diseases can alter one's perspective on life, and their personality. Death due to disease is called death by natural causes.

There are four main types of disease: pathogenic disease, deficiency disease, hereditary disease, and physiological disease. Diseases can also be classified as communicable and non-communicable disease.

The Black Death was one of the most devastating pandemics in human history, peaking in Europe between 1348 and 1350. It is widely thought to have been an outbreak of plague caused by the bacterium Yersinia pestis, an argument supported by recent forensic research, although this view has been challenged by a number of scholars.

Thought to have started in China, it traveled along the Silk Road and had reached the Crimea by 1346. From there, probably carried by Oriental rat fleas residing on the black rats that were regular passengers on merchant ships, it spread throughout the Mediterranean and Europe.

The Black Death is estimated to have killed 30% – 60% of Europe's population, reducing the world's population from an estimated 450 million to between 350 and 375 million in 1400. This has been seen as having created a series of religious, social and economic upheavals, which had profound effects on the course of European history.

It took 150 years for Europe's population to recover. The plague returned at various times, killing more people, until it left Europe in the 19th century.


Alien Invasion

"Perhaps we need some outside, universal threat to make us recognize this common bond. I occasionally think how quickly our differences worldwide would vanish if we were facing an alien threat from outside this world. And yet, I ask you, is not an alien force already among us?"

–– Ronald Reagan


The alien invasion is a common theme in science fiction stories and film, in which extraterrestrial life invades Earth to either exterminate and supplant human life, enslave it under a colonial system, harvest humans for food, or destroy the planet altogether.

The invasion scenario has been used as an allegory for a protest against military hegemony and the societal ills of the time.

H.G. Wells' novel The War of the Worlds is often viewed as an indictment of European colonialism and its "gunboat diplomacy" —setting a common theme for some politically motivated future alien invasion stories.

The theme also exploits invasion panics that were common when science fiction was first emerging as a genre.Prospects of invasion tended to vary with the state of current affairs, and current perceptions of threat. Alien invasion was a common metaphor in US science fiction during the Cold War, illustrating the fears of foreign (e.g. Soviet Union) occupation and nuclear devastation of the American people.

Examples of these stories include "The Liberation of Earth" by William Tenn and The Body Snatchers.In the invasion trope, fictional aliens contacting Earth tend to either observe (sometimes using experiments) or invade, rather than help the population of Earth acquire the capacity to participate in interplanetary affairs.

There have been a few exceptions, such as the alien-initiated first contact that begins the 1951 film The Day the Earth Stood Still, and the Vulcan-initiated first contact that concludes the 1996 film Star Trek: First Contact (although after a failed invasion by the Borg in the rest of the film).

In both cases, aliens decide to visit Earth only after noticing that its inhabitants have reached a threshold level of technology: nuclear weapons combined with space travel in the first case, and faster-than-light travel using warp drive technology in the second.

Technically a human invasion of an alien species is also an alien invasion, as from the point of view of the aliens, humans are also aliens.