Yellowstone Super Volcano

Destruction of biodiversity. This comes up quite often in debate. Basically the more off the same species we have the more easily it could be taken out by a single strain of disease. (Have all the same orange trees suddenly we don't have oranges because of a single strain of disease. Same kind of corn? Now we don't have food)

Most likely occurrences for the death of the human race in chronological order. -scarcity war with nuclear weapons -climate instability due to global warming -expansion of the sun as it begins to burn helium -collision of Milky Way galaxy with the andromeda galaxy -heat death of the universe I left out asteroid/meteor collision and eruption of large hotspot because they could happen at any given moment. So they couldn't be put in a chronological list. The same could be said for a war with another spacefaring species and some other weapon which could cause the human race to wipe itself out. Sorry if I left anything out

We may evolve ourselves out.

Fukushima

Alright So the universe is relatively young It's still early enough for gases to go around and form stars and light After all the stars expel all their gas and supernovas finally end The gases will cool down and all will be dark... That's it The universe is just going be dark for the rest of time...yeahhhhhhhhhhh Watched it in science class before going to lunch :)

Probably a bunch of shit-head militaries going head-to-head with power that no human should possess.

The Rapture

One for luck.... Or two ;) In this scenario, global warming is to blame for our global demise. Again. This time, it's because melting glacial ice is diluting the oceans like our planet is a giant scotch on the rocks. This, in turn, spells disaster for currents, like the Gulf Stream, that connect the world's bodies of water into a cohesive, waterlogged freeway. The Gulf Stream current is driven primarily by thermohaline circulation, a salt- and heat-driven pattern in which cold Arctic water, dense with salt from evaporation, sinks and flows beneath warmer, more buoyant water from the tropics. If the melting glaciers put enough fresh water into the Gulf Stream, the circulation process will stop running. And this will lead to the death of sea life, changes in weather patterns that cause droughts and famine, an increase in weather-related disasters and even a minor ice age [source: Battersby]. Sounds like it might be time to add parkas and mittens to the good ol' end-of-times stockpile, doesn't it? Toward the end of it's life, the Earth's sun will begin expanding like so many Americans' waistlines. But the fact that the sun will need to let out its figurative belt as it ages isn't unusual. As stars like the sun near the end of their natural lifespans and become first red giants and then planetary nebulae, they expand massively, overtaking planets that happen to be nearby. This means that the Earth should eventually be pulled into the sun's dying embrace, unless the sun's decreased gravity enlarges Earth's orbit and allows our planet to escape [source: Cain]. Either way, don't worry about your progeny spiraling into the sun. The star's expanding range of heat and radiation will kill humanity (and evaporate the oceans, and melt the planet's crust) long before it encompasses the Earth. And there's one more bright side to this scenario: The Earth/sun death course isn't expected to take place for another few billion years or so [source: Wagenseil]. That's plenty of time for a different apocalyptic scenario to play out. Or a few more.... Many of us were convinced that by the time we reached adulthood, robots would fetch our coffee, tie our shoes and make our beds. While we're still waiting for a "Jetsons"-style housebot with superhuman domestic skills, there has nonetheless been considerable progress on the smart robot front, including robots that can operate without direct human instruction (like the Roomba, a disc-shaped robot programmed to automatically vacuum carpets) or reassemble themselves when torn apart [source: Trimble]. And on the horizon? Robots that can act as companions for the elderly while monitoring their vital signs or entertain children while keeping parents in-the-know via built-in cameras [source: Camber]. There are predictions that by 2020, we'll be outwitted by the artificial intelligence that we create [source: McKinney]. Or maybe just swept up by hordes of quick-witted Roombas, once cherished as near pets but then discarded, sold on eBay and bent on revenge. Have you ever wondered if your existence -- and the world around you -- is all a dream? Plenty of people, from ancient philosophers to modern moviemakers, have wondered the exact same thing. It's proof that this question is dogging humankind throughout the ages. Take the 2010 movie "Inception" for example. The movie's characters enter dreams and take actions that have real-life consequences. The idea may seem far-fetched, but some researchers believe that people really can influence dreams. All it requires is a little self-suggestion before a snooze: When people think about what they'd like to dream before they fall asleep, it often shows up in their dreamscapes [source: Marikar]. This news makes us want to rethink our late-night reality show addiction, that's for sure. If we can manipulate our dreams -- or those of other people -- it could mean that we're simply dreaming up life as we know it, or that we're the fictional subjects of someone else's dream. Either way, there's no need to worry about how the world will end. Or which guy the bachelorette of the moment will choose. And missing that scene is probably a win-win for everyone.

1.A biological attack from space need not be deliberate. British astronomer Fred Hoyle, whose “steady state” cosmology was for years a serious challenger to the Big Bang theory, was convinced that comets are full of viruses that cause flu epidemics when they rain down on Earth. His ideas, once ridiculed, have been partially vindicated by the discovery that pieces of Mars have landed on Earth, and by studies showing that extremely hardy microbes could survive extended voyages through space. NASA takes the idea of alien pathogens seriously enough that it has an elaborate quarantine protocol for any space sample returned here. The possibility that our planet was seeded with microbial life from Mars (or even, per Hoyle, from a comet) means that we cannot be certain that space microbes would be incompatible with our biology. Odds: still low, given the sketchy evidence that space microbes play any role in terrestrial disease. 2.Back in the 1970s, when it seemed that the sun was not emitting the ex­pected number of particles known as neutrinos, some solar physicists proposed that our star might go through million-year stretches of reduced activity, during which time its brightness could drop by perhaps 40 percent. Although the initial evidence for a solar shutdown evaporated, the mechanism remains possible. Such a dip would put our planet in a deep freeze, and in fact paleontologists now find evidence of one such episode of extreme cold (nicknamed “Snowball Earth”) about 650 million years ago. If the sun dimmed significantly today, the oceans would gradually freeze solid, and most multicellular life on Earth—humans included—would probably go extinct. Odds: low. There is no evidence that other sunlike stars experience such shutdowns, though there is not much proof that they don’t. 3.For eons, icy structures at the bottom of the world's oceans have trapped and stored mass quantities of naturally occurring greenhouse gases, including methane. These gas-storing structures, known as clathrates, may not seem like a big deal since they're miles under sea. However, they're not as insulated from the Earth's surface as one might think -- especially if the planet is gradually warming. Even a minor increase in oceanic temperatures could turn these methane-filled clathrates into superweapons capable of world destruction. The warmer the oceans become, the more the clathrates will swell. When that happens, the clathrates will belch their methane stores to the water's surface in the biggest burp of all time. The release of these greenhouses gases into the atmosphere will trigger more global warming, hotter seas and the release of yet more clathrates' gasses -- up to some 400 gigatons (which is approximately the weight of some 1.5 billion large African elephants, just to give you an idea of the scale we're talking about) [source: Atcheson, San Diego Zoo]. It's our very own version of planetary heartburn, and it could send Earth's life, which depends on delicately balanced climates for its survival, into a tailspin. 4.A supervolcano disaster may sound like a third-grade science project that's gone awry, spewing baking soda-based lava onto the teacher's desk, or like something out of a cheesy sci-fi B-movie. However, supervolcanoes are very real, and the results of one erupting would be far more disastrous than baking soda or bad ratings. Take the supervolcano percolating in Wyoming's Yellowstone National Park, for example. This restless giant could erupt volcanic ash, lava and hot steam without much warning. It would spread destruction from Wyoming to the Gulf of Mexico, prompt significant weather changes across the planet and kill everything within reach of its miles-wide lava path [source: Cessna]. Even the magma of the smallest erupting supervolcanoes could cover some 240 cubic miles (1,000 cubic kilometers) [source: McGuire]. This makes a large supervolcano, like the one in Yellowstone that measures 25 by 37 miles (40 by 60 kilometers), a super threat [source: Handwerk]. And there are five other supervolcanoes around the world, each sufficiently powerful to threaten global extinction. 5.Since 2006, honeybees have been dying by the millions. To date, experts still aren't sure what has been causing up to 90 percent of hives to suddenly die. Why does it matter that such a small creature isn't buzzing about in as large numbers as before? Bees offer billions of dollars of free labor every year as they pollinate agricultural crops. According to the U.S. Department of Agriculture, one-third of what we eat comes from plants that were pollinated by bees [source: USDA]. And that doesn't even factor in statistics about those who eat red meat. Cattle and sheep that are fed pollinated roughage, like alfalfa, rely on bees, too. The same goes for crops in other countries as well [source: Borenstein]. Without honeybees to help propagate our crops, there will be a critical shortage to global food supplies -- and your dinner plate. Over time, this shortage could spiral out of control and lead to looting and other desperate measures, until famine sets in and the world's population starves to death. 6.15: Gigantic Mentos/Diet Coke Collision Some have joked that a Mentos/Coke collision is the apocalypse trigger we'll never see coming, but is there any reality behind the jest? Here's one way a Mentos factory could become a death trap that triggers global collapse. Picture this: A tanker truck carrying bottles of Diet Coke loses control, veers off a highway and breaches the Mentos factory's outer wall. Debris from the wreckage punctures the tanker. The moment the liquid Diet Coke encounters the multiton Mentos inventory, carbon dioxide bubbles rapidly form and expand in pits on the candy's surface. The ensuing explosion sends the Mentos factory sky-high, obliterates neighboring buildings and releases massive amounts of carbon dioxide into the atmosphere. Carbon dioxide is odorless and colorless, so after the shock and destruction of the initial explosion, it won't seem to pose an immediate threat. However, because the gas is heavier than air, it will spread into low-lying areas and prove lethal to the people who breathe it in [source: USGS]. And if wind currents work in its favor, this silent killer could just snuff out -- well, maybe not the world, but a significant local population. Not Serious but :3 7.Evolution used to take eons, but hyper evolution could complete the process in a matter of days or weeks. Forget the snail-paced decades once required for the most helpful genetic traits to be passed from generation to generation. If we manage to master hyper evolution, some believe we could change our own traits in a lifetime -- or even much faster. For example, like lizards that can regrow their own lost tails, humans could employ hyper evolution to regenerate a lost limb. Or they could use a few "master" cells to make a new, better organ, like using stem cells to grow a replacement retina for those who've gone blind [source: Irvine Today]. Even the brain could be gradually replaced as it aged and decayed. Life, it seems, could simply go on forever. How could speeding up the evolutionary process lead to the end of the world? With all this unceasing evolution, human beings could potentially evolve into beings of higher consciousness who don't need their bodies at all. At which point we wouldn't need the earth's atmosphere, either, and could become beings of pure consciousness floating in the ether. With no physical forms to tie us to Earth, a mass exodus from our planet would be only a matter of time. 8.Germs are a hardy lot. We've managed to live with these pesky single-celled critters since cave dwellers first sampled stream-fresh sushi, but it's been an uneasy truce. And sometimes our population has been on the losing end of the human/germ war. The Black Plague comes to mind. Many of the antibiotics that once relegated harmful germs to nothing more than a nuisance have lost their power as bacteria have mutated and produced resistant strains. According to some public health experts, it's entirely possible that a particularly virulent bug could spread like wildfire and wipe out the entire human race [source: Powell]. It's all the more reason to cover your mouth when you cough. 9.Not likely but.... During the 1950s, an entire town in the south of France suddenly suffered hallucinations that caused people to do things like strangle their loved ones, jump out of windows or believe they were being eaten by snakes. No one is certain who -- or what -- caused the madness, but it's suspected that LSD-, mold- or mercury-tainted bread sold by the local bakery was the delivery method [source: Fabricius]. Think mass insanity couldn't happen today? Maybe it already has. In 2010, the World Health Organization reported that more than 450 million people around the world have a psychological disorder [source: World Health Organization]. In 2011, the Centers for Disease Control revealed that half of all Americans would develop mental illness during their lifetimes [source: Reinberg]. And by 2020, depression is estimated to become the second leading cause of disability [source: World Health Organization]. Though a poisoning of our global food supply with psychoses-inducing chemicals could send minds reeling and tear the very fabric of society apart, perhaps we're headed toward similar results all on our own.

:)

Oh, I'll lose interest in this planet eventually.

the sun becoming a red giant the only true answer

Toxins and viruses originally designed for use in warfare. Overpopulation/resource depletion and (resulting) pollution. Continual escalation of war/terrorism.

Nuclear war. Nukes are plentiful and if are ever used in war would essentially create a new ice age. It would kill millions in weeks and many more in only a couple days. The population would eventually dwindle from the cold and lack of food. If you've ever read the Road you'll know how bad this would be.

Being mistaken for Alderaan.

The ongoing nuclear meltdown at fukushima is probably a good starting point.