Planetary-scale Species Extinction of most complex multi-cellular organisms. Not only are humans gone, but most critters with them, leaving only a select few to evolve and refill the biosphere (or, as the name suggests, what's left of it).



[[folder:Anime and Manga]]
* The premise of ''Manga/SevenSeeds'' does this. Scientists predicted that a meteorite with a diameter of several dozens of kilometers and various smaller ones were going to crash on the planet and wipe out all life and cause an ice-age.
* This is the ultimate purpose of the Millenium earl on ''Manga/DGrayMan''. He plans to create another Threesome days of Darkness. The previous one was the biblical disaster known as the great flood mentioned below.
* The prestory to ''Anime/ErgoProxy'' destroyed essentially the entire biosphere of planet earth, though humans still managed to survive ([[spoiler:Granted they no longer were living on Earth, but...]]).
* Mewtwo attempts this in ''Anime/PokemonTheFirstMovie'' via a self-produced global hurricane with the eye around his island. He creates a few dozen clones of the strongest Pokemon he could get, intending to repopulate the world with [[HumansAreTheRealMonsters human-free Pokemon.]] Eventually he changes his mind.
** In [[Anime/{{Pokemon 2000}} the following movie]], the disruption of the harmony of fire, ice and lightning starts similar world-threatening storms.
* Second Impact in Anime/NeonGenesisEvangelion and ''Anime/RebuildOfEvangelion'' melted the Antarctic icecap and generated tidal waves that inundated coastal regions, wiping out cities and large tracts of arable land. Simultaneously, the oceans were poisoned (only in the Rebuild continuity) and left barren and the axis of the Earth shifted. What species survived only endured due to humanity's intervention to maintain the terrestrial ecosystems. Third Impact is expected to escalate the situation to Class 5.
* The anime ''Anime/WolfsRain'', in which the Earth's crumbling biosphere is for all appearances dying of ''old age'', has this as a comparatively optimistic outcome. No wonder the wolves want to leave.
* ''Anime/MacrossDoYouRememberLove'' ups Earth's desolation to this level. In the [[Anime/SuperDimensionFortressMacross original series]], the Earth was devastated, but it was shown to be recovering several years later and there were still several million human survivors scattered about the surface. In the movie, absolutely nothing on the land has survived, although there are apparently still fish in the ocean, with the crew of the ''Macross'' being the only human beings left alive.
* Invoked in ''Anime/SonicTheHedgehogTheMovie'': the setting, Planet Freedom, is a weird blend of WorldInTheSky and FloatingContinent, with all of the various sapient races inhabited the floating "Land of the Sky" and the planet's surface, the "Land of Darkness", being inhabited only by Robotnik and his MechaMooks. Robotnik's plan turns out to be destroying the massive glacial mountain that holds the Land of the Sky to the Land of Darkness, whereupon the combination of their own anti-gravity and the planet's rotation will result in those continents being hurled out of the atmosphere and into space.

* ''ComicBook/YTheLastMan'' is a 3.5, as every male ''mammal'' on the planet dies, save for Yorick and his pet helper monkey and two male astronauts in space. The cause has been vague, but options include an ancient curse or a [[ScienceIsBad biological experiment gone wrong]]. The comic even mentions that, 7 months after the disaster struck, the first species has gone extinct as its reproductive cycle has flown by. It should be noted that the actual short-term effects look more like a Class 1. The looming fact that this is the last generation as far as most of humanity knows barring serious reproductive breakthroughs is anything but glossed over. [[spoiler:Thankfully, in the DistantFinale, we see that Dr. Mann's cloning research has paid off, and it looks like humanity has made a mostly complete recovery -- complete with roughly the same political problems as before -- making this a Class 1 with a recovery period in the decades.]] In addition, [[spoiler:even after rats should have died out with no males to propagate the species -- almost five years on -- some are seen on the streets of Asia, which stuns Mann.]]
* In a three-part story arc at the beginning of John Byrne's post-Crisis Franchise/{{Superman}}, (issues #20-22, 1988) three renegade Kryptonians from an AlternateUniverse do this to their dimension's Earth. The enormity of their crime drove Supes to break his non-killing oath and give them a Kryptonite shower. Much controversy ensued.

[[folder:Fan Works]]
* In ''FanFic/GenderConfusion'', [[spoiler:all living creatures die within the Elemental Nations, effectively wiping out humanity because of Deidara's sacrifice. This occurs due to narrowly avoiding a ''Class 6'' Universal apocalypse.]]
* In ''FanFic/StarWarsParanormalities'', [[spoiler:Emperor Valkor orders Mortaqa to [[LifeDrain harvest the life force]] of every living creature on Christophsis except for Zolph and the Valkoran forces, [[ColdBloodedTorture just to torture Zolph by making him experience Force backlash]] and to give him a preview of how he's going to try to kill him (and to create a [[TheHeartless Forceless symbiote]] for Valkor to assimilate). However, since Emilin trying to suppress Facadma's power as best as she could spared Grein from the attack, other life forms could have been spared, and it's possible some Christophsians were off-world when the annihilation occurred]].

[[folder:Films -- Animation]]
* ''WesternAnimation/WallE'': While (an unknown percentage of) humanity escapes into outer space, the biosphere of Earth completely collapses, with only two living species seen in the film proper: the cockroach, and a small plant (and both seem to be very rare). It appears that no humans survive on Earth itself. The fact that human civilization ''does'' survive (in a way) aboard the starliners makes this a bit of a toss-up between Class 4 and Class 1 -- but really, it's simply a case of humans ''fleeing'' from a Class 4 event.

[[folder:Films -- Live-Action]]
* In ''Franchise/StarWars'' the planet Tatooine use to be a beautiful habitable world, then it was bombarded by the Rakata turning it into the desert world it is now, the few that survived were the Tusken Raiders.
* ''Film/TheQuietEarth'', film version. The ''vast'' majority of the Earth's animals were affected by the Event and disappeared, up to and including most humans. The cause of it was human-engineered, but the fact that animals were also affected pushed it from Class 3 to Class 4. Plants were completely untouched, however.
* Heavily implied in ''Film/ResidentEvilTheFinalChapter'' as a direct result of the worldwide [[TheVirus T-Virus pandemic]]. There's no plant life to be seen anywhere, virtually all animal species have been turned into undead monsters, and the scattered remnants of humanity count less than 5,000 souls - far too few to sustain a genetically viable population in the long run even with the T-antivirus killing off the mutants. Umbrella may be destroyed, but it happened too late, and it's only a matter of perhaps a century until [[DownerEnding Earth is left as nothing but a desolate wasteland devoid of life]].

* According to Literature/TheBible, a Class 4 catastrophe occurred some 4400 or so years ago, with a global flood wiping out nearly everything except for a wooden supertanker-sized boat filled with animals and a human family.
* In ''Literature/TheMoteInGodsEye'', the Earth is a radioactive wasteland kept as a military training preserve by the Empire of Man, as a lesson to all young officers in the Imperial Fleet "to show them what the Empire exists to prevent." The only places on Earth that can support life are the high mountaintops (ironically, some Jamaican Blue Mountain coffee plants have survived the Apocalypse, and they've all been declared the private property of the Emperor for his exclusive use. Smart Emperor...)
* Creator/IsaacAsimov's ''Literature/{{Foundation}}'' series has a galactic empire that has lost knowledge of where Earth ''is'', although it is alluded to several times that it has been rendered fatally radioactive through nuclear war. The protagonists eventually find it.
** In the ''Robot'' series R. Daneel Olivaw and R. Giskard discover that [[spoiler:a spacer plot leads to the Spacers deliberately making the Earth grow radioactive to destroy the Settler society, and the robots refused to prevent the process, believing it will be better for the humanity, since it will force the Earthers to spread out]].
** In the opening chapters of ''The Stars Like Dust'', [[spoiler: the Earth has large areas of nuclear wasteland, and everyone is forced to wear film badges to measure their exposure to radiation]], while in an early Imperial-era novel, [[spoiler: the Earth is revealed to be almost completely uninhabitable]].
* The conclusion of Dougal Dixon's ''Literature/ManAfterMan'' finds the Earth almost totally stripped of life by the evolved, no-longer-recognizable descendents of human space colonists. Its contaminated atmosphere no longer supports any organisms, such that only a handful of native species survive, clinging to deep-sea hydrothermal vents.
* In ''Literature/DownToASunlessSea'', the last nuclear war wipes out almost everyone, except two planeloads of people, who have to run [[spoiler:to Antarctica to start over]], then they discover that [[spoiler:the nuclear weapons have knocked the planet off its axis, meaning that Antarctica is soon going to be in the tropics]]. Depending on which ending your copy has, either it's the end of the world [[spoiler:at which point God steps in to begin all over again, with the last two human survivors the new Adam and Eve]], or they will go out to rebuild the world.
** Mao Zedong apparently gave serious thought to having a few 747s full of Chinese citizens in the air at all times, to provide for just this situation. (In practice, the shockwaves from a global thermonuclear war would likely knock these aircraft out of the air, so it probably wouldn't work.)
* ''Literature/OnTheBeach'' showed humanity completely dying out after a large-scale nuclear war. In the book, it's discussed that dogs, mice and rabbits, being more resistant to the spreading radiation, will outlive humans, but even the rabbits won't last more than a year or so after.
* Scenario #8 in Creator/JohnScalzi's ''[[ Alternate History Search Results]]'' studies what would happen if Hitler had been killed in hitting him with a meteor. Humanity and 93% of all species on Earth are killed off as collateral damage.
* In Literature/TheRiftwarCycle by Raymond E. Feist, Kelewan gets this, not once, but '''twice'''. '''''In the same book.''''' First it starts getting swallowed by an ever-expanding portal to what amounts to the second circle of hell, powered by the deaths of the army trying to stop it. Then, to put an end to ''that'' threat, [[AWizardDidIt Pug]] [[ColonyDrop created a gigantic rift portal that basically slammed a large part of Kelewan's moon into its surface at extreme speed.]] Luckily, a good part of the population escaped to another world.
* The [[ShowWithinAShow Fimbulwinter Game]], played out at Dream Park in ''Literature/TheBarsoomProject'', depicts the near-total freezing of the planet by a crazed Cabal of Inuit sorcerers. Only Arctic natives and organisms have any hope of surviving, and it's hinted that the Cabal's rituals may have overdone it, potentially pushing even these into extinction (and this example into Class 5).
* Sergej Luk'yanenko's ''Линия Грёз'', set in the ''VideoGame/MasterOfOrion'' universe, describes the destruction of the Sakras: the human Empire went for planet-wide meson bombardments on all planets that belonged to the Sakras race or were about to be conquered by them. Technically a Class 6 for those Sakras on the receiving end, the bombardment burns the atmosphere and boils the oceans. Several decades later a human refugee remarks that there is hope for her homeworld - the oceans are about to stop boiling and the planet might be repopulated. The genocide of an entire race is unique in the books, and frowned upon by other races in the games, but repopulating and terraforming planets which were previously rendered sterile is par for the course. It is possible to win the game by becoming the only remaining sentient species.
* Roger Zelazny's ''Literature/DamnationAlley'' is set post-nuclear apocalypse. Most of the surviving population are in coastal cities, while those remaining in the Midwest blame scientists for the catastrophe, and crucify any they catch. There is animal life, but not as we know it.
* ''Alien Earth'' by Creator/MeganLindholm, in which a large group of Humans were rescued by aliens, just prior to the total collapse of Earth's ecosystem. What's left is mostly inedible to these humans, being mostly ground hugging bushes.
* ''Literature/TheNightLand'' is set [[TimeAbyss "billions of years hence"]], after the Sun has died ([[ScienceMarchesOn although that should have incinerated Earth]]). Humans have only survived by sealing themselves inside The Last Redoubt, a massive city inside a pyramid. No one can live in the outside world without special suits. The only things living outside are {{Eldritch Abomination}}s that have colonized the Earth.
* In ''The Green Gods'', massive amounts of climate change caused plants to evolve sapience and begin taking over the world. Many animals, including humans, are on the brink of extinction.
* The hallucinogenic fungus in ''Literature/ChildOfEarth'' ends up spreading to all organic matter until the mold growth is all that remains, having become the titular Child of Earth. (It's also speculated by characters that the lifeform first came to Earth as a remnant of a [[ApocalypseHow/ClassX Class X]] event elsewhere in the universe.)
* In ''[[Literature/TheQuantumThief The Fractal Prince]]'' the Sobornost mind-upload collective has purged most of Earth's surface from life after uploading perfect copies to their giant databanks, and a GreyGoo-nanotech called Wildcode did the rest. Only one city, ironically protected by the Wildcode, still has baseline human population. [[spoiler:By the end even it's gone, after Matjek Chen unleases the Dragons, an even more destructive GreyGoo weapon, on the planet in order to retrieve a copy of his past self. In subversion, upload copies of people continue to live in the Wildcode itself until Chen's purge]]. Amusingly, the sequel novel, ''The Causal Angel'' reveals that the catalyst for all these events was [[spoiler:a deliberately engineered planetwide stockmarket crash.]]
* In ''Literature/TheEndAndAfterwards'', the impact of ''Star Pioneer'' is a 4.5. Human extinction is not immediate, but nearly certain within 50 years. Much, perhaps most of the biosphere is equally doomed. Humanity itself survives, but only by escaping to Alpha Centauri.
* ''Literature/WeAreLegionWeAreBob'': When the Brazilians fired on the HEAVEN-1, this started a war. Every nation got involved, and China eventually destroyed Brazil by dropping asteroids on them. Riker and Homer arrive just as the last Brazilian warships are preparing to drop asteroids on what's left of China, which would render the Earth uninhabitable in weeks instead of decades. Once the warships are dealt with, Riker works to evacuate the fifteen million survivors, since it will take ten thousand years for Earth's biosphere to recover.
* In ''Literature/{{Fragment}}'', a reality TV show crew discovers a teeny, tiny landmass (only about two miles wide) in the middle of the Pacific Ocean known as Hender's Island. They subsequently then discover why no else has discovered the island before: the entire native ecosystem is a horrible eternal orgy of violent dismemberment and splattering death where the food chain breaks down and ''everything eats everything''. As it turns out, the island is a lost [[TitleDrop fragment]] of an ancient Precambrian supercontinent, and as the island got smaller over millions of years, the competition got ever more intense until it became a maelstrom of constant slaughter where the trees drink blood, the grass sprays acid, and the bugs are biological GreyGoo. The characters calculate by computer simulation that if even one organism from Hender's Island reached the mainland, life on all inhabited continents would be wiped out within forty years ''at the most''. Only those living on remote islands might be spared, because as it turns out [[spoiler: Hender's Island life-forms are [[KillItWithWater deathly allergic to salt water]]]].
* While it doesn't happen, ''Literature/TheCountOFMonteCristo'' has a depressed Caderousse discussing humanity's evil, and saying that sometimes it'd be better if it rained two days of powder and an hour of fire.
* ''[[Literature/{{Flanimals}} Flanimals: Day of the Bletchling]]'' ends with the titular monsters wiping out all other Flaniamls on the planet in an apocalyptic war, [[PyrrhicVictory in the process also dooming their next generation to starvation.]] [[spoiler: But by the end, it's revealed that some microscopic sploon is still around and there's a possibility it could evolve to repopulate the world with new Flanimals.]]

[[folder:Live-Action TV]]
* ''Series/BabylonFive'' has [[spoiler:the Vorlon planet killers]]. These planet killers are more likely to be around Class 3-4--one episode has Ivanova requesting atmospheric shuttles to evacuate survivors from the surface of a world devastated by the planet killer. It doesn't destroy the planet, but once it strikes, it's curtains for most of the population, and the few who remain will probably slowly die of starvation, disease, radiation poisoning, or the like unless they are rescued.
* On ''Series/BuffyTheVampireSlayer'', the opening of the Hellmouth is a 4.5. This would release demon hordes onto the Earth, resulting in the extinction of not only the human race, but every other native critter. The natural biosphere would be replaced with a demonic one. This is averted four times, in the episodes "The Harvest", "Prophecy Girl", "The Zeppo", and "Doomed". The release of the First's army of Turok-Han, as averted in the series finale, would apparently have a similar effect.
* The [[SuddenDownerEnding final episode]] of ''{{Series/Dinosaurs}}''. [[MikeNelsonDestroyerOfWorlds Earl Sinclair]] unwittingly engineers a series of catastrophies that causes the extinction of ''all plant life'', and eventually dinosaurs with it. But the scale is so far beyond what really happened to the dinosaurs, it could go beyond even Class 4 on the AW scale.
* The ''Series/DoctorWho'' stories ''The Ark in Space'' and "The Beast Below" disasters where enormous solar flares roasted the Earth, which are ''probably'' the same event. Humanity may well recover (they had warning and were able to evacuate), but the biosphere is implied to be long gone.
** ''The Sontaran Experiment'', the adventure following ''The Ark in Space'', takes place on Earth directly after the events of the previous serial (the Doctor and companions having used a [[TeleportersAndTransporters transmat]] to reach the surface). There is a well-established biosphere and a perfectly reasonable climate.
*** There was even a team of humans looking to recolonize the planet.
* The virus that wiped out humanity in ''Series/TheLastManOnEarth'' apparently wiped out all land-based vertebrate life, at least. There are no cats or dogs or birds to be seen, Carol makes a random comment about how meatballs are a thing of the past, and the gang is shocked when they find a random cow. The fate of non-vertebrates (bugs, worms, etc) and marine life is unclear.
* ''Series/PowerRangersRPM'' ''starts'' with at least a 1.5, but by the end of Ziggy's first scene, it's clear that it's really a 4. Yes, this takes place on Earth.[[note]]An ''[[AlternateUniverse alternate]]'' Earth, we later find out, but still.[[/note]] ''[[DarkerAndEdgier In Power Rangers]]''. Its strongly implied that the means by which the Venjix Virus razed the planet was nuclear carpet-bombing.

[[folder:Tabletop Games]]
* The Exterminatus operation in ''TabletopGame/{{Warhammer 40000}}'' is an attempt to destroy a planet as an economic or military asset. Depending on how thoroughly it's carried out, it usually ranges from Class 4 to Class 5, but can go all the way to X if they ''really'' try. If the bombardees have particularly deep bunkers or the bombardiers get sloppy, this can be as low as Class 2, as in the case of Tallarn (SingleBiomePlanet turned from lush vegetation to desert DeathWorld, but still inhabited).
* ''TabletopGame/TechInfantry'' has a meteor impact do this to the planet Earth, although it is eventually resettled by humans and other life from colony worlds. Then it later gets destroyed in even more spectacular fashion.
* In ''TabletopGame/RocketAge'' Mars and Io have faced Class 4 level events.
* In the ''TabletopGame/DungeonsAndDragons'' Splat book Elder Evils, this is the most likely worst case for four scenarios:
** For the Sertrous scenario; should the heroes fail, the game world's ecosystem would remain unharmed, but most humanoid races would be rendered extinct and replaced by Sertrous' reptilian and demonic followers.
** For the Hulks of Zoretha, failure will mean the awakened Hulks beginning a campaign of extermination against all sentient beings on the game world who could possibly compete with their horrific offspring; the Blood Moon sign throughout the whole campaign [[BittersweetEnding might result in a Class 1 anyway]], given the HatePlague it causes.
** Leviathan's scenario would cause whole continents to sink into the sea, destroying civilized areas; the ecosystem would mostly survive, but not much else. In fact, by the time its Sign reaches Overwhelming (right before the FinalBattle) a Class 1 has already occurred, but hope for recovery remains should the heroes defeat the beast.
** Worst case scenario for the Ragnora would make the world ''better'' suited to support life in general, but the corrupted positive energy caused by the abomination would be "too much of a good thing", causing most species who didn't die from it outright to mutate into horrid, mindless, pseudonatural beings.

* In ''VideoGame/{{Xenoblade}}'', [[spoiler:[[BigBad Zanza]], the soul of [[PhysicalGod Bionis]], causes this whenever his civilization grows advanced enough to leave his body as without ether (i.e. life energy) from living organisms, he would die]].
* The oldest semi-confirmed event in ''VideoGame/{{Touhou}}'' backstory is the creation of Heaven (lit. Celestial World). It occurred by removing a massive Keystone from the Earth, devastating the surface and destroying everything. The good news is that this happened so long ago that even [[TimeAbyss Eirin Yagokoro]] had not yet been born, so it's a good possibility that very little death occurred.
* The Armageddon spell in ''{{VideoGame/Ultima}}'', which is described in the fluff as destroying all life in the world, and when actually cast instantly kills all [=NPCs=]. Depending on the game, there may be two or three survivors, usually the [[PlayerCharacter Avatar]] and [[BigGood Lord British]].
* ''VideoGame/{{Pokemon}}'':
** Stated to be the end result of [[OlympusMons Groudon or Kyogre]] awakening and seizing total power for themselves. Kyogre would drown the world in a torrent of neverending rain, while Groudon would burn the surface into a bone-dry desert. Fortunately, not only are they in opposition to each other and evenly matched in strength, Rayquaza has been known to descend and force them into hibernation whenever they do start fighting.
** In ''VideoGame/PokemonXAndY'', Team Flare attempted to use a DoomsdayDevice to end all human and Pokemon life on Earth (save for themselves and their Pokemon) in order to remake the world in their image.
* The event that kicks the prequel of ''VideoGame/Outpost2'' is the [[ColonyDrop impact of an asteroid]] nicknamed "Vulcan's Hammer" on Earth with the force of 1 billion megatons[[note]]For the record, this is 10 times the force of the [[ Chicxulub event]][[/note]], [[NiceJobBreakingItHero after the attempts using nuclear weapons to divert its trajectory failed and simply caused it to break in two pieces]].
* In ''VideoGame/{{SOMA}}'', [[spoiler:this is the result of the comet Telos hitting the Earth. All life on Earth's surface is killed, but marine life remains unaffected.]]
* In the ''VideoGame/{{Splatoon}}'' series, humans and every other non-aquatic mammal were slowly wiped out by rising sea levels caused by climate change, which wasn't helped by constantly escalating thermonuclear war eventually leading to a stray warhead hitting Antarctica during [[WorldWarWhatever World War V]], causing it to melt even quicker. Aquatic creatures evolved to live on the remaining land in the thousands of years following mammalian extinction, with the only mammals left being Judd (and [[VideoGame/Splatoon2 in the sequel]], his clone). [[WordOfGod The developers have also stated]] that the game's Splatfest events are the result of the Inklings receiving radio waves from our time that have gone into space and been reflected back to Earth, and then interpreting our banal arguments as messages from a divine power to determine the superiority of bread vs. rice, werewolves vs. vampires, etc. It also serves as a source of occasional dark humour, with one conversation between the rapper and DJ [[IdolSinger idols]] Pearl and Marina having them discuss how common it is to find human bones while digging in your lawn.

* ''Webcomic/{{Homestuck}}'': [[spoiler: After Her Imperious Condescension took over Post-Scratch Earth, she turned it into a CrapsackWorld and caused the collapse of civilization and a series of holocausts, [[KillEmAll eventually just flooding the planet]]]]. This should have wiped out most of Earth's biosphere, but apparently some life still survived. This, however, is only true because [[spoiler: she was instructed to do it all by Lord English, an omnipotent and practically omniscient being of destruction.]]
* [[ThePlague Rash Illness]] in ''Webcomic/StandStillStaySilent'' attacks only mammals (except for cats), turning them into trolls (humans), beasts (animals) giants (BodyOfBodies), and general BodyHorror. Seeing how only about 11% of population is immune (probably less at the start of the Illness), it killed most of mammal and human life on Earth, leaving only few scattered remains.
* This happens in ''Webcomic/DeviantUniverse'' during the Dark Future storyline.

[[folder:Web Original]]
* ''Literature/TheJenkinsverse'' sees the alien planet Cimbrean facing a Biosphere Extinction after an unwitting human traveller innocently (and unavoidably) contaminates it with their gut flora when they answer a call of nature. Cimbrean's biosphere has no way of defending against these organisms, which proceed to go mad, spreading at an incredible rate and digesting all organic matter as they go. By the time anybody notices, the contagion has progressed beyond the point where it could be contained, and the only hope of preventing Cimbrean from becoming totally uninhabitable is to import Terran life forms to replace the doomed natives.
* Creator/RoosterTeeth series, ''Day 5'' has this with it seems all animal life. Anything that can fall asleep dies in its sleep. The story is set 5 days after the event with the few people who have managed, depsarately to stay awake while trying to find answers.

[[folder:Real Life]]
* Mass Extinctions (events of this scale) have happened several times in Earth's history:
** [[ The Great Oxygenation Event]], [[ExactlyWhatItSaysOnTheTin in which the appearance of oxygen in the atmosphere]] resulted in the death of many anaerobic multi-cellular organisms.
** The Ordovician-Silurian Extinction was probably caused by natural climate change, and killed 60-70% of all species.
** The Devonian Extinction, caused by more natural climate change (possibly triggered by one or several meteor impacts, or the evolution of plants), wiped out 70% of all species on Earth.
** The Permian-Triassic Extinction was by far the most destructive, killing ''90-96% of all species on the planet''. (Even scientists not given to sensationalism call it "The Great Dying") There are several possible causes, including asteroid impacts, increased volcanism, release of methane, or some combination of the above.
** The Triassic-Jurassic Extinction was probably caused by more climate change, and killed 70-75% of all species.
** The Cretaceous-Paleogene (earlier known as Cretaceous-Tertiary) Extinction is the most famous. Probably caused by an asteroid impact though climate change and mass volcanic eruptions may have also played a role, it killed 75% of all species, including the non-avian Dinosaurs, large marine reptiles, and pterosaurs.
** [[HumansAreBastards Humans]] are seemingly in the process of causing another one, but how serious it gets depends on our actions.
*** Actually, the current (relatively minor) extinction process had been going on for a while. Lots of species of large mammals have been lost in the past 50-80 thousand years. And while humans are most likely part of the reason for the extinction, there is also climate change (no, not the one we have been causing since the 20th century) and the apparition of new diseases are also to be blamed.
* Global nuclear war could leave the world safe for cock-roaches.
* There was a close call during the 1990's when a German biotech company created a genetically modified root bacterium called K. planticola that was supposed to increase the rate at which plant life decomposed into ethanol. What it nearly did is eradicate every plant on Earth. [[ Cracked]] have a decent (and funny) article on it.