People have been predicting the end of the world since human beings were a part of it, but science tells us they have good reason to be afraid. Space is full of planets where life may have once flourished, years ago, that are now dead husks sitting like stumbling blocks in the fabric of the universe. And some say it’s only a matter of time before our own Earth becomes another dead planet, lifeless and hopeless. Really, at this point it’s more a question of how and when the world will end. We’re way past the debate about whether or not it actually will.

So, how much longer have you got on the blue and green marble? Maybe a lot less than you think. There are at least 15 ways the world could end very soon — by 2020, at least. Some you can possibly prepare for and perhaps even prevent, up to a point. But others? We haven’t got a chance of surviving them. Will awareness help you face the inevitable end, or just make you fearful of what’s to come? Read this list to find out how we’re all probably going to die, and let’s find out what the future will bring.

15. Nuclear War

Noted brain Stephen Hawking recently said he believes nuclear war is a very real threat, and he is not alone. Hawking says that aggression could destroy us all in the end. Humans have created the capability of destroying themselves, and to be honest humans can’t really be trusted with that power. There are places around the world where countries, and their leaders, are frighteningly unstable. When these same unstable, unpredictable leaders have the power to unleash nuclear weapons, no one is safe and nuclear war is always a world-ending possibility. As of 2017, Russia, the U.S, France, China, the UK, Pakistan, India and Israel have nuclear warheads. North Korea is attempting to develop working nuclear weapons all the time.

14. Catastrophic Weather

You don’t have to believe in global warming to believe that a hurricane can kill you. Weather events have become more massive and more frequent in recent years, which many scientists attribute to climate change. Scientists predict that hurricanes are becoming more powerful. A massive hurricane can have worldwide effects, and it only takes a few weather events in a few places to create a global disaster that we are not at all prepared to handle. Entire countries could collapse in the face of severe weather, which has been known to be the downfall of entire civilizations in the past.

13. Class Warfare

It sounds like a crazy plot for a book, but class war is a terrifying possibility. The world is becoming more and more divided by the day, and the income gap between the rich and the poor is widening. Economic and tax policies that favor the rich and a decrease in the world’s resources are going to put a strain on basic civility and decency that may render these qualities obsolete. The world is running out of both water and food, and these shortages are getting worse each and every single year. Couple this with a growing divisiveness and a wealthy population with increasing needs and money, and a class war that affects the entire world doesn’t start to look so far-fetched after all.

12. Solar Storm

It’s really hard to believe this is anything other than a Hollywood idea, but scientists say solar storms are very real and we really need to be prepared. There’s a 12 percent chance of Earth being struck by such a storm within the next decade, and those are not great odds. Solar storms can burn out our satellites and disrupt the power grid to create massive blackouts. This will lead to anarchy-like chaos on an epic scale, creating one of the biggest natural disasters in all of human history and probably the most financially damaging event that we have ever seen.

11. Economic Collapse

History already has some idea of what can happen in the face of an economic collapse. But if the world economy collapses, it could truly be our undoing. The demand for food, gas, clothing and other essentials will very quickly outpace the supply. Water and electricity may become unavailable in a matter of days. Such a collapse would cause a panic around the world that would cause skyrocketing interest rates. The complete devaluation of the U.S. dollar and other currencies around the world would happen quickly, and hyperinflation would set in. Trucks may literally be stopped on the highways due to lack of gas. Riots would erupt around the world. If commerce stops in the U.S. for even just a few days, the world economy could fall within a week and a resulting worldwide panic would lead to massive amounts of death and destruction.

10. Asteroid Impact

It’s hard not to be afraid of the thing that killed the dinosaurs. A large asteroid will have more energy when it hits Earth than the atomic bomb. Should such an asteroid strike land instead of water, a country the size of the Netherlands could be completely decimated upon impact. Once the asteroid hits it will release massive dust clouds into the atmosphere, which will affect weather on a worldwide scale. This could create massive and immediate food shortages and block the sun for a period of months or even years. There is an asteroid belt in space very close to the Earth, and there is always a possibility that a massive space object could come hurtling toward us at any moment. Even if we see it coming, how will that help?

9. Pandemic

More than 4 billion people live in urban areas and cities around the world. More and more people are living in cities, and that population is only going to get bigger in the next few years. This makes worldwide epidemic a very real possibility. Overcrowding and big populations are exactly what a virulent disease wants. Massive epidemics are terrifying because they have happened. The Black Death decimated a huge population of Europe in the 14th century. Influenza killed 20 million people in 1918 and 1919. Disease could sweep through the world’s cities quickly and effectively, greatly reducing population and creating a global crisis which might, ultimately, be our downfall. A single antibiotic-resistant, genetically-engineered disease could potentially destroy a huge portion of the world’s population.

8. Robot Wars

It’s a popular topic in science fiction, but that’s because it’s one of those plots that are disturbingly close to the truth. Even some of the world’s most noted academics have said that artificial intelligence can potentially pose a threat to the human race. Stephen Hawking predicted that robots could lead us into a global arms race, and humans could easily end up on the wrong side of the conflict. Humankind is capable of creating very dangerous technology, even if we don’t fully understand what it does, and this can lead to worldwide disaster. Increasingly humanized interfaces and new leaps in artificial intelligence make this a frightening possibility.

7. Worldwide Governmental Collapse

In the history of civilization, we’ve proven that not all systems of government were built to last. Feudalism in Europe, Communism in the Soviet Union, the great dynastic empires of old — all of them fell. Some fell slowly, some seemed to go all at once, but all created worldwide consequences when they fell. How will the world change if there is a massive collapse of government today? There is no way to predict how the world might re-shape itself if a system that’s used on a big enough scale — Capitalism, for example — were it to collapse in the style of other unsuccessful forms of governance. Revolts from citizens, economic crashes, war and natural disasters can all be the catalyst for a government to topple. And when a big enough government topples, it ends up changing the entire world.

6. Black Hole

Throughout history, scientists have learned how to overstep their own bounds. Many inventors and scientists have been killed through their own experimentations. And even at this very moment, the Heavy Ion Collider is studying the mysteries of the universe in the form of antimatter, black holes and all that science fiction stuff that you would much rather watch on a screen. Physicists say that we won’t use the Heavy Ion Collider to create a black hole that will swallow the Earth…but then, it wouldn’t be the first time someone’s experiment went dreadfully, terribly wrong, would it? The only consolation is that if scientists did accidentally create a black hole here on Earth, all life would end so quickly we’d never know it…Does that make you feel better?

5. Supervolcano

Sure it would make a great movie, but this is a possibility that’s uncomfortably real. In fact, it’s happened. Every 100,000 years, approximately, Earth experiences a mega-eruption from a volcano. This already happened in Indonesia 74,000 years ago, a massive event that potentially wiped out most of the world’s population at the time. America has a supervolcano right near the heart of the county, in Yellowstone National Park. It’s called Old Faithful, and it shoots water all the time because it’s releasing pressure. But at any given moment, the super volcano that created Old Faithful may erupt in a different way. Scientists constantly monitor the volcano and say that as of right now, there’s nothing to fear…but that could always change.

4. Fungus

Don’t laugh. Scientists know surprisingly little about fungal infections, far less than they should anyway, and a fungus could literally wipe out the human population. Fungal infections have killed animal populations in the past. Potentially deadly bacteria could easily work its way through the human population because science still knows so little about treating fungus in humans. So many of our infections have become resistant to antibiotics due to over-prescribing that we are frighteningly vulnerable to bacteria, fungus and viruses which could ultimately destroy millions, if not billions, of people. A decline in healthcare and lack of pre-screening, coupled with a pandemic fungal threat, could wreak far more havoc on the population than we can even predict.

3. Anarchy

Civil unrest on a big enough scale could lead to worldwide protests, warfare and a complete collapse of civilization as we known it. A total breakdown in law and order comes with impossible-to-predict effects. Whole countries could fall in a matter of weeks if there are enough angry people revolting against the world they once knew. Many historians believe that Rome, one of mankind’s greatest civilizations, was first destroyed from within before it became weak enough for outside invaders to destroy. If enough unhappy people decide to act out, it could lead to a collapse of global systems and transport us right back to the Dark Ages.

2. Rome Didn’t Fall in a Day

Known as the Snowball Theory, many scientists believe it will not be one event that destroys humankind. They think that several events will culminate in a snowball effect that ultimately causes the crash of the human population. For example, global warming leads to melting ice which releases ancient viruses into the unprepared human population. While virus is wiping out one area of humanity, a global weather event occurs on the other side of the world to destroy a huge chunk of the population on its own. Events continue to snowball until the world is crushed by the effects of it all happening at once. One by one, systems break down until everything falls, spectacularly, apart. This is the Snowball Theory.

1. Reboot

Some scientists have said that a Matrix-style reality may actually be happening to us right this very second. There is actually strong support for the idea that we really do live in the Matrix. Everything around you is a complicated computer program. Everything you see is not real. You have been programmed. And at any given moment, whoever is running the program may come along and simply reboot it — or shut it down. And where will we be then? Elon Musk believes that we are definitely inside a computer simulation. He also believes that the simulation may be nearing its end, and you know what that means…