# What are the most likely causes of human extinction? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [December 8, 2011, 11:34pm UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565 "2011-12-08T23:34:14Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![IMfez](https://avatars.discourse-cdn.com/v4/letter/i/f07891/32.png) [@IMfez](https://boards.straightdope.com/u/IMfez)\ **Post date:** [December 8, 2011, 11:34pm UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/1 "2011-12-08T23:34:14Z")
Just curious if there has been any research in this area and rankings of the most likely causes of extinction for humanity? It’s topic I remain very ignorant of despite all the casual talk I’ve heard about it. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [December 9, 2011, 3:08am UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/2 "2011-12-09T03:08:39Z")
Extinction? Probably none, since we’re still here. Mass death, on the other hand has been documented throughout recorded history by such lovely things as bubonic plague, the Spanish flu, Joseph Stalin and the like. ---
**Author:** ![samclem](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@samclem](https://boards.straightdope.com/u/samclem)\ **Post date:** [December 9, 2011, 3:13am UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/3 "2011-12-09T03:13:32Z")
Moved from General Questions to IMHO. ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [December 9, 2011, 3:57am UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/4 "2011-12-09T03:57:51Z")
Almost extinction - [Toba Event](https://en.wikipedia.org/wiki/Toba_catastrophe_theory). ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [December 9, 2011, 4:04am UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/5 "2011-12-09T04:04:08Z")
Considering how numerous and widespread we are, and how technology could permit at least a few people to survive even in the fact of extreme catastrophes, I don’t think anything short of a major asteroid strike would have much of a shot. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [December 9, 2011, 4:49am UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/6 "2011-12-09T04:49:18Z")
Has to be major and global. Disease could wipe out 90% of people, but there could easily be survivors in isolated areas. Pollution also lacks sufficient global reach. WMDs could do a hell of a job, but still wouldn’t kill everybody. So: Object Impact: Asteroids, giant meteors, enormous space traveling turtles, and the like impacting the planet with sufficient force to cause disintegration, or fill the atmosphere with dust and toxins, making breathing impossible and/or blotting out the sun. Irradiation: The Sun or other object emitting extremely high levels of radiation that penetrate the atmosphere and kill almost everything on the planet. Global Climate Change: This would require a mechanism that operates faster than any now known that causes the planet to heat up or cool down faster than we can find a way to compensate for it. Possibly a catastrophic volcanic event much larger than any other for many millions of years could do that. Micro-Weapons: Miniscule airborn killing machines used to kill our evil enemies who crack the wrong end of their eggs fail to deactivate because of the Unix 2038 bug and continue to float through the atmosphere killing everyone they encounter. Unfortunately, you exhale them before dying, so even a small number of them can eventually kill everyone on Earth. ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [December 9, 2011, 4:57am UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/7 "2011-12-09T04:57:46Z")
> [@TriPolar](#): > > . . . Micro-Weapons . . . How about Terminator-style macro weapons? So long as they have the ability to build factories to build themselves, is there any real advantage in being microscopic? Do we have the capability to create enough poisonous radioactivity – plutonium dust, etc. – to make the world unliveable for humanity? Do we have the capability to make a really big super-duper “Cobalt Bomb” type WMD that would crack the earth’s crust, or rip away big chunks of the atmosphere, etc.? (Obviously, if mass suicide is unanimously agreed upon, we could get the job done with knives. But could a “rogue state” create a human-extinguishing weapon?) ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [December 9, 2011, 5:08am UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/8 "2011-12-09T05:08:58Z")
> [@Trinopus](#): > > How about Terminator-style macro weapons? So long as they have the ability to build factories to build themselves, is there any real advantage in being microscopic? > > Do we have the capability to create enough poisonous radioactivity – plutonium dust, etc. – to make the world unliveable for humanity? Do we have the capability to make a really big super-duper “Cobalt Bomb” type WMD that would crack the earth’s crust, or rip away big chunks of the atmosphere, etc.? > > (Obviously, if mass suicide is unanimously agreed upon, we could get the job done with knives. But could a “rogue state” create a human-extinguishing weapon?) It seems unlikely that a ‘rogue state’ would have the resources to produce a world killing weapon of macro size. But we could do it to ourselves unintentionally if John Titor doesn’t come back with the fix for Unix. ---
**Author:** ![Foggy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/foggy/32/1082_2.png) [@Foggy](https://boards.straightdope.com/u/Foggy)\ **Post date:** [December 9, 2011, 8:05am UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/9 "2011-12-09T08:05:52Z")
You might find this interesting. This guy came up with a classification system for real end of the world scenarios. [Eschatological Taxonomy](http://www.openthefuture.com/2006/12/an_eschatological_taxonomy.html) Here is a handy [Chart](http://www.openthefuture.com/images/apocoscale.jpg) ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [December 9, 2011, 8:25am UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/10 "2011-12-09T08:25:19Z")
> [@TriPolar](#): > > Has to be major and global. Disease could wipe out 90% of people, but there could easily be survivors in isolated areas. Pollution also lacks sufficient global reach. WMDs could do a hell of a job, but still wouldn’t kill everybody. A disease that wipes out 90% of everybody might not only fail to wipe out the last 10% (due to isolation) but might fail because some few people will have natural immunity, just by the luck of their random genetic make-up. Not only that, but as the population regenerates from this remnant few, that whole new population will have widespread immunity! It is imaginable that AIDS could play out like this. (Aside from the fact that with modern medical research and technology, even susceptible people can live a long time.) It is known that there are some people who have natural resistance to AIDS. In fact, there was news a few months ago of a man who seems to have been cured of AIDS by a stem cell transplant from a resistant individual. [The Man Who Had HIV and Now Does Not](http://nymag.com/health/features/aids-cure-2011-6/) From the lede: > [@](#): > > Four years ago, Timothy Brown underwent an innovative procedure. Since then, test after test has found absolutely no trace of the virus in his body. The bigger miracle, though, is how his case has experts again believing they just might find a cure for AIDS. > [@](#): > > After chemo, the leukemia came back. Brown’s last chance was a stem-cell transplant from a bone-marrow donor. Hütter had an idea. He knew little about HIV, but he remembered that people with a certain natural genetic mutation are very resistant to the virus. The mutation, called delta 32, disables CCR5, a receptor on the surface of immune-system cells that, in the vast majority of cases, is HIV’s path inside. People with copies from both parents are almost completely protected from getting HIV, and they are relatively common in northern Europe—among Germans, the rate is about one in a hundred. Hütter resolved to see if he could use a stem-cell donor with the delta-32 mutation to cure not just Brown’s leukemia but also his HIV. (From the photo of him, though (taken about when this article was written), he sure still looks horribly sick.) ---
**Author:** ![Foggy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/foggy/32/1082_2.png) [@Foggy](https://boards.straightdope.com/u/Foggy)\ **Post date:** [December 9, 2011, 8:58am UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/11 "2011-12-09T08:58:29Z")
Oh hell, might as well link to this as well [Apocalypse How](http://tvtropes.org/pmwiki/pmwiki.php/Main/ApocalypseHow) Yes it’s a TV Tropes Link. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [December 9, 2011, 3:17pm UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/12 "2011-12-09T15:17:19Z")
You might be surprised to know that wiki has a pretty good series of articles on the topic. Start here [Human extinction - Wikipedia](http://en.wikipedia.org/wiki/Human_extinction) ---
**Author:** ![Mr.Excellent](https://avatars.discourse-cdn.com/v4/letter/m/f19dbf/32.png) [@Mr.Excellent](https://boards.straightdope.com/u/Mr.Excellent)\ **Post date:** [December 9, 2011, 4:12pm UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/13 "2011-12-09T16:12:16Z")
> [@Senegoid](#): > > (From the photo of him, though (taken about when this article was written), he sure still looks horribly sick.) Yah. Most of the articles I read around this time emphasized that this was _not_ a cure any sane person would want if they had any choice. Many had quotes from doctors saying that they would prefer to take their chances with HIV and antiretrovirals. ---
**Author:** ![Anne\_Neville](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)\ **Post date:** [December 9, 2011, 4:19pm UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/14 "2011-12-09T16:19:32Z")
I think disease is unlikely. We tried using disease, specifically [myxomatosis](http://en.wikipedia.org/wiki/Myxomatosis#Spread_of_the_disease), to wipe out rabbits in Australia. Initially, it killed a lot of rabbits, but there were some with natural immunity. The rabbit population rebounded, and the lethality of myxomatosis went down. My money’s on asteroid impact or supervolcano. Also, the sun, like all Main Sequence stars, is getting brighter as it ages. We think that, in about a billion years, it will get bright enough to boil Earth’s oceans. If we haven’t migrated to another planet by then, that would certainly make humans go extinct. ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [December 9, 2011, 5:53pm UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/15 "2011-12-09T17:53:40Z")
> [@Trinopus](#): > > How about Terminator-style macro weapons? So long as they have the ability to build factories to build themselves, is there any real advantage in being microscopic? Terminator style macro weapons are complex machines that have chemicals, moving parts. Nano-machines don’t work that way. But they can form solid metal shapes like knives and stabbing weapons. Actually, he is probably referring to the “Grey Goo” scenario. Some sort of self-replicating nano-machine that just keeps perpetuating itself at a geometric rate until it consumes everything (or at least consumes things critical for human survival). ---
**Author:** ![OldGuy](https://avatars.discourse-cdn.com/v4/letter/o/3bc359/32.png) [@OldGuy](https://boards.straightdope.com/u/OldGuy)\ **Post date:** [December 9, 2011, 6:52pm UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/16 "2011-12-09T18:52:19Z")
There’s also the possibility of a gamma ray burst occurring in the Milky Way and pointed at Earth > **[Gamma-ray burst](https://en.wikipedia.org/wiki/Gamma-ray_burst)** > > In gamma-ray astronomy, gamma-ray bursts (GRBs) are immensely energetic explosions that have been observed in distant galaxies. They are the most energetic and luminous electromagnetic events since the Big Bang. Bursts can last from ten milliseconds to several hours. After an initial flash of gamma rays, a longer-lived "afterglow" is usually emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, microwave and radio). > The intense radiation of most observed GRBs is thought to be rel... ---
**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:** [December 9, 2011, 8:10pm UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/17 "2011-12-09T20:10:31Z")
I don’t think there’s any single event that could do it, since we’re too numerous and wide-spread (even before you consider our technology). You’d need at least a one-two punch. Say, a nearby gamma-ray burst cauterizes half the planet and photo-opacifies the atmosphere to kill most of the rest, leaving only survivors in mostly self-contained habitats with non-solar energy sources. Then, an epidemic of some sort spreads through those habitats, some time before the few years it would take for the atmosphere to clear up. ---
**Author:** ![purplehorseshoe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/purplehorseshoe/32/2996_2.png) [@purplehorseshoe](https://boards.straightdope.com/u/purplehorseshoe)\ **Post date:** [December 9, 2011, 8:27pm UTC](https://boards.straightdope.com/t/what-are-the-most-likely-causes-of-human-extinction/605565/18 "2011-12-09T20:27:30Z")
> [@Mr.Excellent](#): > > Yah. Most of the articles I read around this time emphasized that this was _not_ a cure any sane person would want if they had any choice. Many had quotes from doctors saying that they would prefer to take their chances with HIV and antiretrovirals. If this isn’t a total hijack of the OP, could anyone clear up why this is? Is stem cell therapy painful or debilitating in some way? (Well … more painful & debilitating than either having leukemia or undergoing chemo and radiation?)