There's a host of natural disasters that could spell doom for humankind, but perhaps our biggest threats actually come from humanity itself.
With all of us usually worried about our own little problems, most people don't realize just how many world-ending threats are actually looming on the horizon—just one tiny mishap away. In fact, many existential dangers are already here, taking place as we speak. Here are 9 horrifying but highly probable ways the world could come to an end.
A giant meteor strikes Earth
Let's start with a classic. An asteroid impact is one of the most cliché world-ending scenarios out there, but there's good reason to fear it. For one, it has happened in the past, albeit not to the human race. We've all heard about the gigantic asteroid that brought the reign of the dinosaurs to an end—and, for all our intelligence and technology, another one could do the same to ours.
This doomsday scenario is not as unlikely as you think either. Plenty of meteors hit Earth on a regular basis, and it takes only a moderately-sized one (about half a mile wide) to trigger a global catastrophe that could destroy our entire civilization—even if some humans survive. These kinds of asteroids are estimated to impact our planet once every 250,000 years, roughly, but it could happen much sooner than that.
What's worse, we don't need an asteroid that big to disrupt our way of life entirely. Smaller meteors fall on Earth regularly, and many of them can cause severe damage to our infrastructure and kill thousands. In 1908, for example, a 200-foot comet fragment fell over the Tunguska region in Russia, releasing nearly 1,000 times the energy of an atomic bomb.
We get hit by a burst of gamma-rays
Here's a threat most people haven't heard about. Roughly once a day, an extremely bright flash of energy gleams over the sky, outshining almost everything else. We can't see these flashes with our naked eye because we don't naturally have gamma-ray vision, but trust me, they're out there. They actually are gamma-ray bursts, a recently-discovered phenomenon that usually originate in very distant galaxies, probably when two collapsed stars merge.
The thing about these bursts is that they are exceptionally powerful—releasing about 10 quadrillion times the energy of the sun. So, yeah, they could pretty much devastate anything in their path.
Here's what most scary about them: scientists don't fully understand the phenomenon yet, which means they can't really predict it. What we do know is that before they occur, the dead stars would be nearly undetectable, so it's unlikely that we'd ever get a warning in advance that a burst is coming our way. Not that it would matter, though—we couldn't really do anything about it except say goodbye to our loved ones.
Indeed, the gamma-ray bursts we know about have occurred so far away that we barely get affected by them. But it's impossible to say if one could happen in our galactic neighborhood anytime soon, and if it takes place even as far as 1,000 light years away (that's very, very far away), there would be no escaping its power. The event would appear as bright as the sun, and release such energy that our atmosphere would be mostly fried. It wouldn't immediately kill us, but it would deplete our ozone layer, meaning our shield from the sun's most harmful radiation would be gone. That in itself would wipe us and most species off in a matter of months.
Massive solar flares fry the planet
But we don't have to go that far to find a likely world-ending threat: our own sun could be enough to destroy civilization at any time if it suddenly went haywire. And the killer might ultimately be an event that actually keeps us alive in normal circumstances: solar flares, a.k.a. coronal mass ejections.
You see, usually, solar flares are powerful enough to warm us, but not so strong as to fry us. Problem is, this could change in either direction without previous warning as far as we know, as scientists don't fully understand the complex dynamism behind these essential ejections. Astrophysicists have found evidence that other sun-like stars can briefly brighten up to a factor of 20, most likely as a result of what's known as superflares—ejections millions of times more energetic than our sun's regular activity. We don't know how or why these superflares occur, and thus cannot rule out the possibility that our own star could suddenly send one our way, effectively destroying our atmosphere and humankind in the process.
A lethal pandemic annihilates the population
As we all know, lethal diseases are not uncommon at all—but we usually have the means to fight them off eventually, either through our own immune systems or medicine. Throughout history, we've seen it happen over and over: deadly viruses or bacteria suddenly mutate and infect a human, who then transmits it to the next, and then the next, and so on, eventually causing a gruesome epidemic that threatens the stability of a whole region. It happened many times in the ancient world. It happened in the middle ages during the infamous Black Death, which wiped out one third of Europe's population and changed the face of society forever afterward. More than 20 million lives were lost during the 1918 flu epidemics. And that's not even counting HIV, which is still killing people to this day.
It's not difficult to imagine, then, that a new antibiotic-resistant strain could suddenly appear somewhere in the world. If it's contagious and deadly enough, we would be caught off-guard. Considering that we're living in a hyper-connected world where people can travel anywhere faster than ever, combined with the fact that more and more diseases are creating resistances to our medical technologies, this apocalyptic scenario is not far-fetched at all.
A rogue black hole passes near us
Granted, this one's not that likely (as far as we know), but it's an actual possibility so terrifying it just had to make the list.
If a regular star came flying passed us relatively closely, we'd know way before it approach because, well, we can see it. But black holes are another story. Their gravity is so strong that not even light can escape it—thus their name. There are a few ways we can detect a black hole, mostly through gravitational disturbances around it, but we'd have little notice if one were headed our way. At first, scientists would notice some odd behavior in nearby star systems as planets are thrown from their orbits by the hole's powerful gravitation. The closer it gets to us, the more noticeable these disturbances become. Soon, light coming from other stars would be distorted enough to make the black hole almost visible.
Eventually, the hole's force would be devastating for Earth. It doesn't have to get too close for our entire solar system to be disrupted, as every planet leaves its orbit and Earth is sent hurtling away from the sun and into the frigid depths of space, where life would be unsustainable. From our vantage point, we'd just suddenly see the sun get smaller until it disappears completely into the distance as we freeze to death almost immediately. Worst case, though, the black hole sucks us into it, which means all matter on the planet would become infinitely extended as we approach the event horizon. It would probably be a disturbing and painful passing.
Particle accelerators accidentally destroy the planet
So, we know science has gotten to places previous generations never even dreamed of. As technology advances in gigantic steps, so does the quality and range of scientific experiments, which are now manipulating matter at the subatomic level—which itself might bring unforeseen consequences.
One of the main technological devices for experimental physics is the famous particle accelerator, which, as the name fittingly suggests, is an apparatus that accelerates subatomic particles to extremely high velocities via electromagnetic fields. This helps us understand how matter behaves. Thing is, it could also end up setting off a chain of events that could spell disaster for the planet—at least theoretically. For example, a specific collapse in accelerated matter could create a subatomic black hole that slowly rips Earth apart. It could also produce strangelets, a kind of rare particle that destroys any bit of matter it touches.
Scientists are not too worried at this point, though. According to most physicists, our particle accelerators are nowhere near as powerful to actually be a threat, at least not today. But it's not unlikely that we eventually build and activate a much bigger accelerator—you know, in the name of science.
Nuclear or global war ravages Earth
It's incredibly scary to think we're one button-press away from global war. Just the U.S. and Russia alone have nearly 19,000 active nuclear warheads—enough to set off a nuclear winter that would put an end to our society.
A few decades ago, international tensions rose so high, humanity found itself incredibly close to global nuclear war, as the Soviet Union and the U.S. struggled for world dominance during the Cold War. And it's not that there's no international tensions today The difference is, humankind now has more firepower than ever, and it's not only nuclear in nature. Biological weapons are a thing, with the capacity to trigger a devastating pandemic that would obliterate most of the world's population. These bioweapons are even cheaper and could potentially be more gruesome than your now-more-traditional nuclear threat.
Regardless of the kind of weapon, the point is the stakes have never been higher when it comes to politics and war. And given the extremely volatile nature of humans, that's truly a scary thought.
Global warming makes the planet uninhabitable for humans
It's no secret that climate change and global warming are ongoing and already starting to devastate entire communities (despite what a few conspiracy theorists, a.k.a. climate change deniers, might say). Human activity has sent far more greenhouse gases into the atmosphere than our planet is able to sustain, accelerating a climatic cycle that would otherwise take thousands of years to occur.
This basically means that the earth's climate will be radically altered in the coming decades, triggering a catastrophic chain of events that will eventually lead to the complete disruption of our economic and social infrastructure, taking millions (if not billions) of lives in the process.
Thing is, this is already happening, so out of all the items in this list, climate change is actually the most likely culprit that will inevitably bring about the end of the world as we know it.
Global ecosystems collapse due to human exploitation
But even if the climate itself doesn't get us, human activity has been so disruptive already that it threatens to undermine nature's delicate balance, threatening the collapse of entire ecosystems on which society relies. Species are becoming extinct at an alarming rate and whole areas of once-fertile land are being rapidly eroded, all of which will lead to the complete depletion of the resources we need to survive. Once they are gone, our own extinction will quickly follow.
Think about: the loss of a single type of insects such as bees could threaten to devastate all of humankind through a kind of ripple effect whose consequences will only add up over time. The destruction of the Amazon is another example of human irresponsibility. We're not only killing off billions of non-human lives; we're stupidly eradicating the very basis of our survival.
So, yeah. If a natural event doesn't get us, we're certainly making sure we get us ourselves. Either way, things are not looking good for humanity if we keep heading in this direction. We can't do much about black holes or gamma-ray bursts; but we could at least prevent self-destruction. We can only hope we do.
Other articles for you:
Why Ecocide Should Now Be Considered An International Crime Against Humanity
Humans Threaten The Lives Of One Million Species In Current Mass Extinction Event
The Teenage Activist Who's Rallying The World Against Climate Change