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But when things do end, if they do, how is the world going to go? Will another Ice Age destroy all living things or will humans destroy themselves?
We’ve rounded up some of the many theories about how human civilisation as we know it will cease to exist.
Nuclear weapons have already devastated major Japanese cities. And that was when only one country possessed the power to create such weapons.
But, now that most of the world's powerful nations know the secrets to nuclear warfare, how long will it take for the world to go up in smoke?
Stanford Professor Emeritus in Engineering Martin Hellman became convinced in the 1980s that nuclear power would destroy the world.
By 2009, he determined children born around that time stood a 10 per cent chance of dying because of nuclear weaponry.
A world-ending volcanic eruption in Yellowstone National Park will spew enough lava to will 'set the sky ablaze,' according to the Discovery Channel documentary Apocalypse How.
The cataclysmic eruption would send 'deadly volcanic debris hurtling hundreds of miles,' the documentary warned, with ash falling so thick you'd think it was snowing. That ash will then mix with moisture and turn to a deadly cement that will engulf the planet.
The ash will travel across the globe, causing significant drops in temperature and turning once-temperate areas into tundras.
'And you say, 'well it could erupt tomorrow, it could erupt 50,000 years from now,'' author Lawrence Joseph said in the documentary.
The most recent Yellowstone eruption, 640,000 years ago, was a thousand times bigger than Mount St. Helens. And scientists believe the ash released from the explosion scattered debris across the entire West Coast.
Between 2003 and 2010, conditions in the national park, such as significant caldera uplift, led scientists to fear another supervolcanic eruption.
However, we got lucky and nothing happened.
Scientists discovered in 1995 a patient in Madagascar who's strain of the plague bacillus resisted multiple antibiotics.
'These results are even more alarming since this multidrug resistance has emerged in one of the bacterial species that is most pathogenic for humans, and since the chances of the patient's survival are directly linked to the rapidity of the antibiotic treatment,' an Institut Pasteur researcher said at the time.
The same resistance plasmid has also been found in Salmonella, causing researchers to worry about its transmission. If the resistance plasmid becomes more widespread, a single disease could potentially wipe out the human race.
'Our results imply that high-level resistance to multiple antibiotics could quickly and naturally occur in the plague bacillus,and this would represent a major medical, public health, and biodefence threat,' the researchers said.
U.S. defence chiefs warned then-President Bush that global warming poses a greater threat than than terrorism and Britain could become 'Siberian' within 20 years according to a 2004 article from The Guardian.
Warmer temperatures -- which are are causing glaciers and sea ice to melt -- could threaten millions, according to a United Nations prediction in 2007.
That same year, Planet Ark stated the earth's temperature increased by .74 degrees Celsius over the past 100 years, causing a major decrease in the snow and ice in the Himalayas.
That melting ice could cause an increase in avalanches and floods.
Back in 2003, Cornell University professor David Pementel and Mario Giampietro, a senior researcher at the National Research Institute on Food and Nutrition, warned the United States' population couldn't exceed 200 million if the country wanted to maintain a sustainable economy.
By 2011, the U.S. population reached 311,591,917.
That drastic leap accelerates the pair's prediction that by 2050, only .6 acres of farmland will be available to grow food for each U.S. citizen, less than half the acreage each person needs to maintain current dietary standards.
To keep up with internal demand, Pementel and Giampietro predicted the U.S. will stop exporting grain by 2025, devastating the country's economy and causing millions around the world to starve.
Asteroids already killed the dinosaurs. And now, they're coming for the humans.
Back in September 2010, we reported that a gigantic asteroid, named 1999 RQ36, was making its way toward Earth and was expected to hit the plant on Sept. 24, 2182.
The asteroid, first discovered in 1999, is more than 1,800 feet wide and has a 1-in-1,000 chance of hitting the planet.
If Earth is to have any hope of survival, scientists will have to divert the asteroid more than 100 years before it's expected to hit Earth.
Asteroid Apophis, which has a 1-in-250,000 chance of hitting Earth, is set to collide with Earth in 2036.
As early as 2009, scientists were convening in California to discuss the possibility that humans are one step away from creating machines they can't control.
Eric Horvitz, president of the Association for the Advancement of Artificial Intelligence, told The New York Times scientists need to start thinking of the ramifications of their research into predator drones and computer viruses.
Computer scientist Vernor Vinge proposed the Singularity theory in 1993, in which he says in 30 years humans will have the technological tools to create superhuman intelligence.
'Shortly after, the human era will be ended,' he wrote.
It's happened before.
The world's climate changes work in cycles, leading scientists to believe 'that the earth will once again ice over,' according to scientists at Argonne National Laboratory.
While Argonne's scientists didn't predict a time frame, Finnish nuclear scientists are preparing. Back in 2009, the scientists began digging underground passages and chambers that they hope will hold Finland's spent nuclear fuel.
Their challenge was to find a spot that could withstand another ice age, which they predict might come in about 20,000 years.
Deadly earthquakes come in all shapes and sizes. But all can be deadly.
'Some of the most devastating seismic events have been ones that happened deep out at sea,' Scientific American Contributing Editor John Rennie said in a Discovery Channel documentary about the apocalypse.
One of the largest earthquakes ever measured hit in 2004 off the coast of Northern Sumatra, killing more than 227,000 people.
Japan, one of the countries most prone to earthquakes, now stands a 70 per cent chance of being hit by a 'massive earthquake within the next four years,' CNN reported.
The biggest earthquake on record, which clocked in at 9.5 on the Richter Scale, happened in 1960 in Valdivia, Chile. The quake killed approximately 1,655, injured 3,000, and caused $550 million in damages.
The Yucatán Peninsula impact that may have killed the dinosaurs has been calculated at 12.55 on the Richter Scale.
We've already seen a taste of what a tsunami can do to a country.
But a mega tsunami, which can be caused by a massive earthquake or underwater volcanic eruption, has the potential to wipe out countries across the globe.
'Tsunamis are among the most destructive forces known to man,' Scientific American Contributing Editor John Rennie said in a Discovery Channel documentary about the apocalypse.
A BBC documentary from 2000 predicted 'a colossal wave will one day devastate the coast of America.'
'Say if a fault in the centre of the Pacific, suddenly, suddenly shifts, cities could be underwater in a second, 'Astrophysicist Dr. Ian O'Neill warned in a Discovery Channel documentary about the apocalypse.
Such a catastrophe struck Lituya Bay, Alaska, in 1958, causing a wave that was hundreds of meters high and resulted in mass destruction.
Scientists don't know what caused the Lituya Bay mega tsunami, but say it was a 'previously unknown force of destruction,' according to the BBC documentary.
E.T. is all fun and games until he invades.
While science hasn't quite proven the existence of aliens, making it difficult to predict an invasion, famed scientist Stephen Hawking says we should fear such an encounter.
'Such advanced aliens would perhaps become nomads, looking to conquer and colonize whatever planets they could reach,' Hawking said in a Discovery Channel documentary.
'If so, it makes sense for them to exploit each new planet for material to build more spaceships so they could move on. Who knows what the limits would be?'
Despite a lack on conclusive research, Weekly World News predicts aliens will invade Earth as soon as November 2012.
And let's not forget Roswell.
If fossil fuels run out, farmers won't have gas to power tractors and machines. They might be forced to rely on horses to till fields, meaning agriculture could crash.
And without nitrogen, farmers would lose fertiliser's main ingredient, meaning they would have to rotate crops and produce less.
Governments would feel the burn as well. Peak oil could trigger 'a general systemic crisis,' according to the German army, which could 'in extreme cases lead to open conflict.'
The Germany army speculated in 2010 that there is 'some probability that peak oil will occur around the year 2010 and that the impact on security is expected to be felt 15 to 30 years later.
We've got three billion years before it happens, but everyone from the Hayden Planetarium to Harvard professors predict the Milky Way and Andromeda galaxy collision are on a collision course.
The impending collision will cause a new, elliptical-shaped galaxy.
Experts claim the collision could knock our solar system to the fringes of the galaxy and might cause Earth to move from the Milky Way into the Andromeda galaxy.
The crash might also cause the sun to collapse into a white dwarf, essentially destroying Earth, depending on where the sun is in its orbit at the time of collision.
A violent zombie outbreak can be caused by a variety of factors, the most plausible being brain parasites.
Parasite Toxoplasma gondii turns human brains into 'mindless, zombie-like slaves' and is actually pretty common.
The parasite, originally founds in cats, has infected the brains of more than 60 million U.S. residents.
When scientists infected rats' brains with the parasite, they found rats were no longer scared of cats' odours and were actually attracted to it, essentially equaling a hijacking of the rats' free will.
Not worried yet? You should be.
Canadian researchers determined that a zombie attack would 'lead to the collapse of civilisation.'
Hypercanes are described as 'a massive tower of wind that stretches out to the heavens, and laid out across entire continent.'
The ocean temperature would have to reach 122 degrees Fahrenheit to create a hypercane, which has not yet happened but is still possible.
MIT scientist Kerry Emanuel says such a massive storm -- winds could reach 500 miles per hour and sea spray and storm would punch a hole in the stratosphere 20 miles above Earth's surface -- could be triggered by a large asteroid hitting an ocean or a giant undersea volcano creating intense heat.
If the asteroid in 2182 doesn't get you, a supercane could.
Author John Christopher may have hit the nail on the head with his post-apocalyptic science fiction novel The Death of Grass.
The book details a virus capable of wiping out crops across the world. The virus sweeps from country to country, destroying agriculture and causing mass starvation. The resulting famine cause a breakdown in civil law.
Plant viruses travel quickly, as they can be transmitted through seeds, insects, and replanting.
The world got a taste of such a catastrophe when two viruses destroyed hundreds of thousands of dollars worth of crops, according to Penn State College of Agricultural Sciences.
And in 1999, the mosaic plant virus ravaged 60 per cent of Africa's cassava crop.
Galactic dust from the Milky Way is passing through our solar system more often than normal, according to Universe Today.
That dust, a dark nebula, could cause severe global climate change.
However, the effects of dark nebula aren't well understood, so we might be safe.
'If you had a solar storm that struck in the dead of winter, people could suddenly find themselves freezing to death,' Scientific American Contributing Editor John Rennie said in a Discovery Channel documentary about the apocalypse.
'We could be looking at the breakdown of society as we know it,' Astrophysicist Dr. Ian O'Neill warned in the documentary.
During a super solar flare in 2008, English astronomer Richard Carrington saw two blinding white lights appear in the sky. Before dawn the next day, skies across the globe boasted red, green, and purple auroras, causing telegraph systems to go haywire.
A 2006 solar flare was so intense it damaged NOAA's X-ray Imager. The flare produced such a strong CMEs, a cloud of charged particles and detached magnetic loops, that once the cloud hit Earth it disrupted the planet's magnetic field.
Since the magnetic field is getting weaker all the time, scientists are worried.
Scientists predict that by the end of 2012, the sun will move out of its current cycle, causing strong CMEs and throwing Earth through a loop.
'We don't really know what this next solar maximum will be like,' Solar Physicist Dr. Holly Gilbert said in the documentary. 'It might throw us some surprises,'
Global warming strikes again.
Experts speculate there is a 45 per cent chance the thermohaline circulation in the North Atlantic Ocean could collapse by the end of the century.
The circulation is a system of currents in the Atlantic Ocean that move warm water into the northern hemisphere.
'We found that there is a 70 per cent likelihood of a thermohaline collapse, absent any climate policy,' said Michael Schelsinger, an atmospheric sciences professor at the University of Illinois Urbana-Champaign.
If the effects of global warming are not reversed, researchers worry the collapse of the Atlantic heat conveyor belt could cause a cooling in northwest Europe and worsen droughts in equatorial Africa.
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