# What kind of post-apocalyptic scenarios would result in 100% destruction of the human race? **URL:** \ **Category:** Factual Questions\ **Created:** [October 12, 2012, 3:42pm UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526 "2012-10-12T15:42:44Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![drastic\_quench](https://avatars.discourse-cdn.com/v4/letter/d/e36b37/32.png) [@drastic\_quench](https://boards.straightdope.com/u/drastic_quench)\ **Post date:** [October 13, 2012, 9:09pm UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/41 "2012-10-13T21:09:53Z")
Even if you find a method that’s 99% effective, which you won’t, you’re left with 70 million humans or more. 70 million commiserating, humping, breeding humans. ---
**Author:** ![Michael63129](https://avatars.discourse-cdn.com/v4/letter/m/3da27b/32.png) [@Michael63129](https://boards.straightdope.com/u/Michael63129)\ **Post date:** [October 14, 2012, 12:15am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/42 "2012-10-14T00:15:11Z")
> [@ekedolphin](#): > > Took me awhile to find an article that I first read years ago, but [here](http://www.ldolphin.org/twentyways.html) are 20 ways… I disagree strongly with some of these, such as a [geomagnetic reversal](http://en.wikipedia.org/wiki/Geomagnetic_reversal), which has happened hundreds of times in the past - yet never caused any mass extinctions (including of human ancestors, the last one occurring 780,000 years ago). So compasses might get messed up, but who needs a compass when we have GPS, which also tells you exactly where you are? The Sun might also produce another [Carrington flare](http://en.wikipedia.org/wiki/Solar_storm_of_1859), but that won’t do much besides destroy most satellites and the electric grid (of course, millions would die as a result of the infrastructure damage, but many people would survive, people in areas without electric grids would never even notice anything aside from auroras). Also, as I said previously on gamma-ray bursts, they would only have a sterilizing effect on half of the Earth, with the other half being affected by the destruction of half of the ozone layer, which would recover in a decade or two; humans could still survive by avoiding all sun exposure and growing food in greenhouses (glass blocks UV, greenhouses would also help against the cool spell that would follow). It’d probably most likely be something either triggered by humans or a result of war, but even most of those probably wouldn’t eliminate the human race. Unless for example, we made a bunch of factories to fill up the atmosphere with [sulfur hexafluoride](http://en.wikipedia.org/wiki/Sulfur_hexafluoride#Greenhouse_gas) (assuming there is enough raw material) and trigger a Venus greenhouse effect, but not if we just went on our way until all fossil fuels are gone. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 14, 2012, 12:31am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/43 "2012-10-14T00:31:52Z")
Another consequence of a nearby gamma-ray burst would be that the radiation would cause nitrogen-burning in the atmosphere, resulting in various nasty nitrogen oxides, some of which are opaque. If the burst is near the Equator, you could blot out the Sun over most of the planet, to give a long winter as follow-up to the initial flash-killing. ---
**Author:** ![Michael63129](https://avatars.discourse-cdn.com/v4/letter/m/3da27b/32.png) [@Michael63129](https://boards.straightdope.com/u/Michael63129)\ **Post date:** [October 14, 2012, 12:56am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/44 "2012-10-14T00:56:10Z")
> [@Chronos](#): > > Another consequence of a nearby gamma-ray burst would be that the radiation would cause nitrogen-burning in the atmosphere, resulting in various nasty nitrogen oxides, some of which are opaque. If the burst is near the Equator, you could blot out the Sun over most of the planet, to give a long winter as follow-up to the initial flash-killing. That’s why I mentioned the greenhouses as also being able to keep it warm. As for whether those nitrogen oxides (or other byproducts) would make the atmosphere itself toxic to breathe, it would depend on how much forms at low altitudes vs. higher up; many of the gamma rays would be absorbed before reaching the ground but enough would still get through to cause problems (although articles that I’ve seen focus mainly on the ozone depletion as the biggest killer). ---
**Author:** ![ekedolphin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ekedolphin/32/10003_2.png) [@ekedolphin](https://boards.straightdope.com/u/ekedolphin)\ **Post date:** [October 14, 2012, 5:07am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/45 "2012-10-14T05:07:46Z")
> [@Michael63129](#): > > I disagree strongly with some of these… "I ain’t finalizin’ and saying that they _will,_ Baby John. I’m just sayin’ that they _might."_😉 ---
**Author:** ![hibernicus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hibernicus/32/2802_2.png) [@hibernicus](https://boards.straightdope.com/u/hibernicus)\ **Post date:** [October 14, 2012, 7:57am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/46 "2012-10-14T07:57:06Z")
> [@Chastain86](#): > > Indeed. I’m interested in scenarios in which humankind has died out in total, but the planet itself continues to spin. This would eliminate any scenario in which the Earth was entirely consumed by fire, crushed by a massive meteor, etc. Just to be clear, are you allowing scenarios where all life is destroyed? Because if so, an impact large enough to disrupt the earth’s crust will kill every human, but the earth will continue to spin and the crust will quickly reform. ---
**Author:** ![Cheshire\_Human](https://avatars.discourse-cdn.com/v4/letter/c/5f8ce5/32.png) [@Cheshire\_Human](https://boards.straightdope.com/u/Cheshire_Human)\ **Post date:** [October 14, 2012, 12:23pm UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/47 "2012-10-14T12:23:54Z")
> [@drewtwo99](#): > > I think the OP has already ruled out large-scale impact, but [something like this](http://www.youtube.com/watch?v=LlF8APEkh-E)would definitely wipe out all human life on Earth. > > Very fascinating to watch. [Another version of the same video, with narration.](http://www.youtube.com/watch?v=xB7IHNnyJ00) ---
**Author:** ![Chastain86](https://avatars.discourse-cdn.com/v4/letter/c/f9ae1b/32.png) [@Chastain86](https://boards.straightdope.com/u/Chastain86)\ **Post date:** [October 14, 2012, 4:36pm UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/48 "2012-10-14T16:36:09Z")
> [@hibernicus](#): > > Just to be clear, are you allowing scenarios where all life is destroyed? Because if so, an impact large enough to disrupt the earth’s crust will kill every human, but the earth will continue to spin and the crust will quickly reform. Originally I looking for a circumstance where animal life is destroyed to 100% totals – no humans, but perhaps still plant and/or bacterial “life” that would allow for the Earth to continue to evolve and spawn something anew in a few million years. Though I suppose if nothing else fits the bill, a cataclysmic event that leaves the Earth itself a lifeless rock will do. 🙂 ---
**Author:** ![Chastain86](https://avatars.discourse-cdn.com/v4/letter/c/f9ae1b/32.png) [@Chastain86](https://boards.straightdope.com/u/Chastain86)\ **Post date:** [October 14, 2012, 4:38pm UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/49 "2012-10-14T16:38:01Z")
> [@Cheshire\_Human](#): > > [Another version of the same video, with narration.](http://www.youtube.com/watch?v=xB7IHNnyJ00) I guess you didn’t watch it all the way through to notice the… ahem, “improvised musical cue” in this video. 😛 ---
**Author:** ![Johanna](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johanna/32/8318_2.png) [@Johanna](https://boards.straightdope.com/u/Johanna)\ **Post date:** [October 14, 2012, 8:13pm UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/50 "2012-10-14T20:13:00Z")
The soundtrack of “The Great Gig in the Sky” was an inspired choice, especially timing the impact with the beginning of the woman’s singing. Perfect. ---
**Author:** ![drastic\_quench](https://avatars.discourse-cdn.com/v4/letter/d/e36b37/32.png) [@drastic\_quench](https://boards.straightdope.com/u/drastic_quench)\ **Post date:** [October 14, 2012, 8:23pm UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/51 "2012-10-14T20:23:55Z")
> [@Johanna](#): > > The soundtrack of “The Great Gig in the Sky” was an inspired choice, especially timing the impact with the beginning of the woman’s singing. Perfect. Oh, yeah. That video still gives me tingles. ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [October 15, 2012, 12:41am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/52 "2012-10-15T00:41:29Z")
> [@Chastain86](#): > > Originally I looking for a circumstance where animal life is destroyed to 100% totals – no humans, but perhaps still plant and/or bacterial “life” theres a couple of ones here which haven’t been mentioned: > **[Human extinction](https://en.wikipedia.org/wiki/Human_extinction)** > > Human extinction or omnicide is the hypothetical end of the human species, either by population decline due to extraneous natural causes, such as an asteroid impact or large-scale volcanism, or via anthropogenic destruction (self-extinction). > Some of the many possible contributors to anthropogenic hazard are climate change, global nuclear annihilation, biological warfare, weapons of mass destruction, and ecological collapse. Other scenarios center on emerging technologies, such as advanced ar... The anoxic event leading to lack of a breathable atmosphere would seem to do the trick. “oceanic anoxic events may have been characterized by upwelling of water rich in highly toxic hydrogen sulfide gas, which was then released into the atmosphere. This phenomenon would likely have poisoned plants and animals and caused mass extinctions.” > **[Anoxic event](https://en.wikipedia.org/wiki/Anoxic_event)** > > An anoxic event describes a period wherein large expanses of Earth's oceans were depleted of dissolved oxygen (O2), creating toxic, euxinic (anoxic and sulfidic) waters. Although anoxic events have not happened for millions of years, the geologic record shows that they happened many times in the past. Anoxic events coincided with several mass extinctions and may have contributed to them. These mass extinctions include some that geobiologists use as time markers in biostratigraphic dating.\[3 Human... Could wipe out all animal life but some plants and bacteria would survive. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [October 15, 2012, 1:31am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/53 "2012-10-15T01:31:26Z")
A mechanism that would destroy at least all humans and probably most larger animals would involve a widespread mutation of one of our symbiotic bacteria such that it would start to produce prions. If the prions cause destruction of a vital organ, the result would be a progressive condition leading to death, like CJD (mad cow type spongiform encephalopathy). If the bacteria are not themselves directly harmful and the prion attack were subtle enough, the vector might very well not be discovered before the race was past the tipping point (like with CJD, where one just gets stupider until the breathing reflex is lost). And there is no known defense against prions, especially as the immune system is unable to even detect their presence. ---
**Author:** ![Johanna](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johanna/32/8318_2.png) [@Johanna](https://boards.straightdope.com/u/Johanna)\ **Post date:** [October 15, 2012, 2:38am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/54 "2012-10-15T02:38:20Z")
We didn’t evolve from bacteria—rather, we seem to have evolved from Archaea, creatures that look just like bacteria, except they’re weirder. Archaea are known for their phyla of extremophiles—my candidates for the last lifeforms left alive in catastrophic environmental conditions that would wipe out all others (say a sulfuric anoxic event like the one mentioned above combined with catastrophically high temperatures). If Archaea evolved to intelligent mammals once, maybe they could again. ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [October 15, 2012, 2:56am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/55 "2012-10-15T02:56:47Z")
I don’t think a meteor that blocks out the sun for a decade would kill us. We know enough about growing crops with artificial light via that we could create small settlements that lived off of indoor grown crops until the sun came back strong enough to grow crops outdoors. As far as a pathogen, there is genetic diversity in life that will prevent all of us from being susceptible. Even if every person on earth gets infected (unlikely) and even if it kills 99.9% of people, that still leaves 7 million people. A giant meteor that turns the crust into lava would probably kill us (I don’t know of people could survive underground from something like that). The planet getting sucked into a black hole, or knocked into the sun would kill us all too. ---
**Author:** ![Cheshire\_Human](https://avatars.discourse-cdn.com/v4/letter/c/5f8ce5/32.png) [@Cheshire\_Human](https://boards.straightdope.com/u/Cheshire_Human)\ **Post date:** [October 15, 2012, 3:24am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/56 "2012-10-15T03:24:56Z")
> [@Chastain86](#): > > I guess you didn’t watch it all the way through to notice the… ahem, “improvised musical cue” in this video. 😛 No, actually I specifically _looked_ for that one, then linked to it. For exactly the reason you found. 😛 yourself. :p;) ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [October 15, 2012, 7:12am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/57 "2012-10-15T07:12:26Z")
Personally, I’d say we’re so pervasive and generally adaptable that the only non-planet-killing event that would get us all would be something that was targeted at us, specifically and continuously. So either Skynet or aliens, basically. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [October 15, 2012, 7:41am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/58 "2012-10-15T07:41:54Z")
> [@solosam](#): > > You’re talking about something astrological, like a solar radiation burst, massive coronal flare, or asteroid strike. Most other scenarios (disease, war, etc) would all leave at least a handful of people alive. Even a pathogen with 100% mortality rate would fail to find a vector to carry it to some isolated jungle tribes. Any such event would have to effect the entire world. “This week is not the time to be making long term plans. Be wary of change and large, fast-approaching strangers” ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [October 15, 2012, 7:48am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/59 "2012-10-15T07:48:25Z")
An atmospheric transformation like Earth’s changeover to an oxygen atmosphere. Some organism evolves that pumps out something that renders the atmosphere unbreathable. Chlorine gas is one possibility I’ve heard; some mutant algae starts producing chlorine along with oxygen. ---
**Author:** ![ekedolphin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ekedolphin/32/10003_2.png) [@ekedolphin](https://boards.straightdope.com/u/ekedolphin)\ **Post date:** [October 15, 2012, 9:30am UTC](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526/60 "2012-10-15T09:30:28Z")
And of course, there’s always the [Voluntary Human Extinction Movement](http://en.wikipedia.org/wiki/Voluntary_Human_Extinction_Movement), an environmental movement that encourages people to abstain from reproduction in order to bring about the gradual voluntary extinction of mankind. The group states that a gradual decrease in human population would prevent a significant amount of man-made human suffering. _chuckles wryly_ At the rate I seem to be going, I might join the Voluntary Human Extinction Movement involuntarily. In any event, it’s an interesting read. [Previous page](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526.md?page=2) [Next page](https://boards.straightdope.com/t/what-kind-of-post-apocalyptic-scenarios-would-result-in-100-destruction-of-the-human-race/637526.md?page=4)