|note||source 1||link 1||source 2||link 2||source 3||link 3||source 4||link 4||source 5||link 5||source 6||link 6||source 7||link 7||source 8||link 8||source 9||link 9|
|Which apocalyptic threats are most likely to wipe out Earth's population and when?||for sunburst only||unused|
|category||man made?||short description||short notes on scores||stats||timescale||probability||seriousness||rounded average of probability + seriousness||suddenness||inevitability|
|scenario||what kind of hazard is it?||man made or natural?||what would happen?||how much of a threat is it?||related facts and figures||when is it most likely to happen? or for ongoing events, become catastrophic||how likely is it to happen?||if it did happen, how likely would it be to end the human race?||if it were to end the human race, what's the quickest it could do it?||how difficult is it to prevent?|
|conflict, environment, other, space, technology||5 within a decade, or it's already happening, 4 within a century, 3 within a millennium, 2 within a million years, 1 more than a million years away||5 certain or virtually certain, 4 high, 3 medium, 2 low, 1 very low (but not zero)||5 certain or virtually certain, 4 high, 3 medium, 2 low, 1 very low||5 it's all over, 4 move to Mars, 3 live dangerously, 2 check bucket list, 1 keep calm||5 within a year, 4 within a decade, 3 within a century, 2 within a millennium, 1 more than a millennium||5 impossible or virtually impossible, 4 very difficult, 3 prevention possible but difficult, 2 could be averted, 1 relatively easy to prevent|
|underpopulation||other||man made||declining fertility rates in many countries mean the human population starts to drop. eventually humans die out.||women are now having half as many children each as 50 years ago, but the global population will continue to rise before it falls because of the number of people already alive. states would likely step in to bump up birth rates if they got too low. we have to worrying about populations ageing, not dying out.||global fertility rate in 1950: 5 children per woman. |
global fertility rate in 2005: 2.5 children per woman.
replacement fertility rate (children per woman to keep the population the same size): 2.1.
year the world will hit the replacement fertility rate, on current trends: 2020.
|3||1||1||1||2||1||UN World Population Prospects, 2012 edition||http://esa.un.org/wpp/||Economist||http://www.economist.com/node/14743589|
|honeybees die out||environment||man made||wild bee populations collapse because of multiple stresses including pesticides and the varroa mite. crops go unpollinated and food supplies run out.||pressing: many colonies have already collapsed. other insect pollinators exist (flies, wasps), but many are also declining. the switch to other crops would hit world food prices, hammering the poor. the rich could breed their own captive bees, hand-pollinate, or invent drones to do it.||100 crop species provide 90% of the world's food. 71 of these species are pollinated by bees.||5||3||1||2||3||1||UNEP||http://www.un.org/apps/news/story.asp?NewsID=37731||UNEP||http://www.unep.org/dewa/Portals/67/pdf/Global_bee_colony_disorder_and_threats_insect_pollinators.pdf||Wikipedia (other pollinators)||http://en.wikipedia.org/wiki/Pollinator|
|geoengineering fail||environment||man made||humanity's attempts to tackle climate change using geoengineering go badly wrong||theoretical at the moment as no solutions have yet been tried. some – such as spraying clouds with sea salt or seeding oceans with iron filings – have potentially dangerous side effects. things could get bad, we just don't know how bad.||how geoengineering could work:|
1. we remove carbon dioxide from atmosphere – for example by building artificial trees or seeding oceans to increase CO2 absorption
2. we reflect more sunlight back into space – for example by spraying clouds to make them more reflective, or launching mirrors into space
|3||2||2||2||3||1||Crazy Climate Solutions (previous IIB project)||https://docs.google.com/a/informationisbeautiful.net/spreadsheet/ccc?key=0AvZNxPpzAwyIdEFmLUVVZFRObnJ3ZHVpV3NaLVlHZEE#gid=1||Royal Society (2009)||http://royalsociety.org/uploadedFiles/Royal_Society_Content/policy/publications/2009/8693.pdf|
|posthumanity||technology||man made||technological bodily augmentation coupled with genetic engineering means recognisably human people no longer exist||arguably we'd no longer be human, but a posthuman society of highly enhanced beings could be a good thing – unless a flawed superintelligence stepped in and infected us all with a lethal computer virus.||posthumans might be|
: more intelligent
: more emotionally aware
: physically stronger
|3||3||1||2||3||3||Bostrom 2006||http://www.nickbostrom.com/posthuman.pdf||Agar 2010||http://mitpress.universitypressscholarship.com/view/10.7551/mitpress/9780262014625.001.0001/upso-9780262014625-chapter-2|
|methane release||environment||man made||climate feedbacks such as methane 'burps' from melting permafrost and seabed deposits mean global warming spirals out of control – runaway climate change||scary, but unlikely to be catastrophic. methane is already bubbling out of a warmer Arctic. however, most methane hydrates are buried so deep that at current rates of warming they will not be affected over the next thousand years.||methane is a greenhouse gas 20 times more potent than CO2. |
methane stored in frozen hydrates:
est. 99% in undersea sediments
1% in permanently frozen regions (permafrost).
if 0.1% of it were released (unlikely), atmospheric methane concentrations would increase by >60%.
Nature Scitable: 'A conservative estimate (Boswell & Collett 2011) for the global gas hydrate inventory is ~1.8x103 Gt C, corresponding to CH4 volume of ~3.0x1015 m3 if CH4 density is taken as 0.717 kg/m3. In the unlikely event that 0.1% (1.8 Gt C) of this CH4 were instantaneously released to the atmosphere, CH4 concentrations would increase to ~2900 ppb from the 2005 value of ~1774 ppb (IPCC 2007).' 1779 to 2900 is approx. 63% increase. 'Catastrophic, widespread dissociation of methane gas hydrates will not be triggered by continued climate warming at contemporary rates (0.2ºC per decade; IPCC 2007) over timescales of a few hundred years. Most of Earth's gas hydrates occur at low saturations and in sediments at such great depths below the seafloor or onshore permafrost that they will barely be affected by warming over even 103 yr. Even when CH4 is liberated from gas hydrates, oxidative and physical processes may greatly reduce the amount that reaches the atmosphere as CH4.'
|alien invasion||conflict||natural||we encounter hostile aliens with better technology, who conquer us in cinematic fashion||extremely low probability at the moment – no evidence of extraterrestrial life so far. but if humanity develops into an intergalactic civilization the chance of an alien encounter rises. they might be friendly. but our odds of winning against a more advanced, hostile civilization would be slim.||known exoplanets as of August 2014: |
chances of any of these planets harbouring life: unknown
|2||1||3||2||5||5||suspected = unconfirmed Kepler candidates.||Bostrom 2002||http://www.nickbostrom.com/existential/risks.html||exoplanets.org||http://exoplanets.org/|
|nuclear armageddon||conflict||man made||countries or terrorist groups start a nuclear war||still huge. the weapons and even the fallout wouldn't kill everyone, but the dust might. recent models show even a small nuclear war could shift enough dust into the upper atmosphere to block out sunlight around the world, triggering a nuclear winter. the resulting catastrophic famines could kill billions, and disease could do the rest.||100 Hiroshima-sized detonations would |
: produce 5 million tonnes of soot
: cool the climate for 25 years
: kill up to 1 billion people.
Nuclear weapons in the world: more than 17,000.
Futurologist Anders Sandberg, Oxford University: "The Cuban Missile crisis was very close to turning nuclear. If we assume one such event every 69 years and a one in three chance that it might go all the way to being nuclear war, the chance of such a catastrophe increases to about one in 200 per year."
|5||3||2||2 - rounded down||3||2||Mills et al 2014||http://climate.envsci.rutgers.edu/pdf/MillsNWeft224.pdf||Robock et al 2007||http://climate.envsci.rutgers.edu/pdf/acp-7-2003-2007.pdf||Scientific American (Robock and Toon, 2009)||http://climate.envsci.rutgers.edu/pdf/RobockToonSciAmJan2010.pdf||Nature (Robock comment piece)||http://climate.envsci.rutgers.edu/pdf/NatureNuclearWinterComment.pdf||The Conversation||https://theconversation.com/the-five-biggest-threats-to-human-existence-27053||The Conversation|
|natural pandemic||environment||natural||a deadly microbe strain – either newly evolved or an existing one – causes a global pandemic||a new global pandemic (not Ebola – it isn't contagious enough) could spread rapidly and kill billions. but some would be resistant, and evolution doesn't favour parasites that wipe out their hosts, so the odds are good for humanity.||Europeans killed by Black Death, 1347-51, minimum: 25 million (25% of Europe's population at the time). |
People killed by Spanish Flu in 1918-19: 50-100 million (3-5% of world's population)
Natural pandemics have killed more people than wars. However, natural pandemics are unlikely to be existential threats: there are usually some people resistant to the pathogen, and the offspring of survivors would be more resistant. Evolution also does not favor parasites that wipe out their hosts, which is why syphilis went from a virulent killer to a chronic disease as it spread in Europe. World population in 1918-19 assumed to be 1.9bn.
|The Conversation||https://theconversation.com/the-five-biggest-threats-to-human-existence-27053||The Conversation||https://theconversation.com/from-human-extinction-to-super-intelligence-two-futurists-explain-26617||BBC (plague 200m deaths)||http://news.bbc.co.uk/1/hi/health/1576875.stm||WHO (Ebola)||http://www.who.int/csr/disease/ebola/en/||Quora (Ebola)|
Jaax et al 1995 via Quora (Ebola)
Wikipedia World population historical estimates
Olea and Christakos 2005 (plague deaths 14thC)
CDC (Spanish flu deaths)
|flawed super AI||technology||man made||a malign or badly-programmed technological superintelligence annihilates humankind||sounds straight out of sci-fi, but taken very seriously by futurologists – a superintelligence may only be decades away. intelligence is no guarantee an AI's aims would be aligned with ours. an AI would only have to be slightly more intelligent than us to be unimaginably dangerous.||superintelligence scenarios from philosophy|
1. superintelligence renders humans obsolete
2. the controllers of the first superintelligence form a powerful world government
3. a superintelligent paperclip-producing machine turns the entire Universe into paperclips
|4||3||2||3||5||4||Anders Sandberg in the Conversation||https://theconversation.com/the-five-biggest-threats-to-human-existence-27053||Daniel Dewey (Future of Humanity Institute) in Aeon magazine||http://aeon.co/magazine/world-views/ross-andersen-human-extinction/|
Bostrom 2002 (world government)
|Bostrom 2003 (paperclips)||http://www.nickbostrom.com/ethics/ai.html|
|Venus syndrome||environment||man made||extreme runaway climate change makes Earth as hot as its nearest neighbour Venus||distant. it's physically possible, but for a full-on Venus scenario, as well as ultra-high atmospheric greenhouse gas levels we'd need a brighter Sun – which won't happen for a billion years, by which point we'll be worrying about the Sun anyway (see death of Sun)||average Earth surface temperature: 15°C. average Venus surface temperature: 464°C.||1||1||4||3||2||4|
Hansen et al, 2001: 'Given the transient nature of a fossil fuel CO2 injection, the continuing forcing required to achieve a terminal Venus-like baked-crust CO2 hothouse must wait until the Sun's brightness has increased on the billion year time scale. However, the planet could become uninhabitable long before that.'
Hansen et al 2001
|Climate Victory||http://www.climatevictory.org/venus.html||James Hansen, Storms of my Grandchildren (book)||http://www.amazon.com/Storms-My-Grandchildren-Catastrophe-Humanity/dp/1608195023||James Hansen||http://www.columbia.edu/~jeh1/mailings/2013/20130415_Exaggerations.pdf|
NASA (Earth surface temperature)
NASA (Venus surface temperature)
|unknown unknown||other||?????||something very deadly and unavoidable that we have no clue about – yet||cannot be ruled out – we don't know everything about the Universe. why haven't aliens contacted us yet? perhaps there's a 'great filter' that means intelligent life will always die out.||according to researchers from Oxford and MIT, the risk of a totally unforeseen Earth-destroying event can be calculated based on the age of the Earth. the risk is less than 1 in a billion per year.||1||1||4||3||5||5|
Tegmark and Bostrom 2005: 'Numerous Earth-destroying doomsday scenarios have recently been analyzed, including breakdown of a metastable vacuum state and planetary destruction triggered by a "strangelet'' or microscopic black hole. We point out that many previous bounds on their frequency give a false sense of security: one cannot infer that such events are rare from the the fact that Earth has survived for so long, because observers are by definition in places lucky enough to have avoided destruction. We derive a new upper bound of one per 10^9 years (99.9% c.l.) on the exogenous terminal catastrophe rate that is free of such selection bias, using planetary age distributions and the relatively late formation time of Earth.'
|Anders Sandberg in the Conversation||https://theconversation.com/the-five-biggest-threats-to-human-existence-27053||Tegmark and Bostrom 2005||http://arxiv.org/abs/astro-ph/0512204||Aeon||http://aeon.co/magazine/world-views/ross-andersen-human-extinction/|
|antibiotic resistance||environment||man made||antibiotics are rendered useless as bacteria become resistant. people die from routine infections and currently treatable diseases like TB.||worrying. multidrug-resistant bacteria are spreading and new antibiotics are not being developed. but not likely to wipe us out – the human race survived for millennia before antibiotics were discovered, and the birth rate would probably rise as mortality increased.||number of years until people going for simple operations die from routine infections, according to Dame Sally Davis, the UK's Chief Medical Officer: 20. |
deaths from multidrug-resistant bacteria in the EU per year: 25,000.
deaths from meticillin-resistant Staphylococcus aureus in US per year: 19,000 - more than HIV/AIDS, Parkinson's diease, emphysema and homicide combined.
|Lancet / WHO||http://www.thelancet.com/journals/lancet/article/PIIS0140673609620766/fulltext?_eventId=login&&rss=yes|
|overpopulation||environment||man made||human population growth damages the environment and outstrips Earth's capacity to produce food, causing disastrous famines||barring a disaster, populations will continue to rise for the next few generations. a serious threat to billions, unless we start producing more food. long-term, some humans would probably survive – populations tend to keep themselves in check either because fertility falls or lots of people die. but we may have destroyed the environment by then (see Climate change, Loss of topsoil)||people on the planet |
today: 7 billion
in 2100, UN forecast: 11 billion
|4||5||1||3||2||4||medium population scenario 10.85 bn||UN World Population Prospects, 2012 edition||http://esa.un.org/wpp/|
|rising sea levels||environment||man made||warming climate causes thermal expansion of oceans and melting of ice caps and glaciers. global sea levels rise.||already happening and set to get worse. could drown coastal cities, triggering social unrest and making millions homeless. there'd be less land to go round but some humans would survive, plus we'd have centuries to move inland.||current sea level rise, per year: 3.2mm. |
: by 2100: up to 1.2m.
: by 2300: up to 3m.
: if all ice on Earth melted: 80m.
Potsdam Institute for Climate Impact Research: 3.2 mm rise per year and accelerating
Horton el al 2014 - 2100 and 2300, upper end of median likely range, high warming scneario.
|Sea Level (previous research)||https://docs.google.com/a/informationisbeautiful.net/spreadsheet/ccc?key=0Aqe2P9sYhZ2ncFliSmVvb2dwRk45TkJOUUFRaFltUEE#gid=5||USGS||http://pubs.usgs.gov/fs/fs2-00/||IPCC 2007, 'centuries or longer' for sea level rise of >10m|
|supervolcano||environment||natural||a massive volanic eruption releases great clouds of ash, blocking out sunlight and cooling the globe. several years of crop failures result, causing great famines.||real. there's a dormant supervolcano in Yellowstone Park, US. but we've survived one before – just. the Toba eruption 74,000 years ago cooled the planet by 3-5°C and likely reduced the human population to a few thousand, causing a genetic bottleneck.||supervolcanoes erupt roughly once every 50,000 years|
the last one occurred 26,000 years ago (Taupo, New Zealand)
number of times the Yellowstone supervolcano has erupted in the last 2 million years: 3
years ago the last eruption occurred: 600,000
global cooling if it erupted again: 10°C for a decade
largest volcanic eruption of last millennium: Tambora, Indonesia, in 1815
cooling in Northern Hemisphere caused by Tambora eruption in 1816, the 'year without a summer': 1°C
|2||4||2||3||3||4||Simon Redfern (Cambridge Professor Earth Sciences) in The Conversation||https://theconversation.com/how-earths-devastating-supervolcanoes-erupt-21943||Rampino 2002 (supereruptions every 50k years, Tambora)||http://www.eos.ubc.ca/~mjelline/website212/rampino02.pdf||Self 2006||http://rsta.royalsocietypublishing.org/content/364/1845/2073.full|
|Matrix scenario||other||natural||the Universe turns out to be a simulation and it gets shut down||hypothetical. if there are future posthuman civilisations advanced enough to create simulations of their own past and they choose to do so, then we are almost certainly living in a simulation. but we may never find out – at least until we try to create our own simulations.|
actors who turned down the role of Neo in The Matrix (1999), eventually played by Keanu Reeves
: Will Smith
: Nicolas Cage
: Brad Pitt
: Val Kilmer
|1||1||5||3||5||5||Bostrom 2002||http://www.nickbostrom.com/existential/risks.html||Simulation Argument.com (Nick Bostrom)|
|Nick Bostrom in New Scientist, 2006||http://www.simulation-argument.com/computer.pdf|
CNN (Will Smith)
MTV (Nicolas Cage)
|rogue black hole||space||natural||a black hole enters the Solar System, or the Large Hadron Collider (LHC) malfunctions and creates one||the black holes created by the collider are microscopic and unstable, so pose no threat. the possibility of a black hole entering our Solar System is extremely remote, but if it did, the intense gravitational pull would rip Earth apart.||nearest black hole to us: Cygnus X-1, 6070 light years away||1||1||5||3||5||5||Space Answers||http://www.spaceanswers.com/solar-system/what-would-happen-if-a-black-hole-entered-our-solar-system/||Universe Today||http://www.universetoday.com/38434/black-hole-on-earth/||NASA||http://www.nasa.gov/mission_pages/chandra/multimedia/cygnusx1.html|
|EMPs||space||natural||huge electromagnetic pulses (EMPs) – from geomagnetic storms or nuclear weapons – knock out computers, power lines and data centres||big, but probably not terminal. could cut out food, water and fuel supplies for weeks to large areas. plus, we're overdue a geomagnetic storm. we can''t prevent them, but we could protect ourselves better.||we can expect a massive geomagnetic storm around every 150 years |
estimated risk of one occurring within the next decade: 12%
how we could protect ourselves
: more standby transformers
: build EMP-resistant tech + gadgets
: better space weather forecasting
Lloyds: the mid-point estimate for the return period of a Carrington-level is 150 years, with a reasonable range of 100 - 250 years. NASA: In February 2014, physicist Pete Riley of Predictive Science Inc. published a paper in Space Weather entitled "On the probability of occurrence of extreme space weather events." In it, he analyzed records of solar storms going back 50+ years. By extrapolating the frequency of ordinary storms to the extreme, he calculated the odds that a Carrington-class storm would hit Earth in the next ten years.
The answer: 12%.
|The Conversation||http://theconversation.com/electromagnetic-disaster-could-cost-trillions-and-affect-millions-we-need-to-be-prepared-30296?utm_medium=email&utm_campaign=Latest+from+The+Conversation+for+11+August+2014+-+1842&utm_content=Latest+from+The+Conversation+for+11+August+2014+-+1842+CID_2d0ed6388c3f73698e8ca9e6876fbf23&utm_source=campaign_monitor_uk&utm_term=Electromagnetic%20disaster%20could%20cost%20trillions%20and%20affect%20millions%20We%20need%20to%20be%20prepared||Lloyds Emerging Risk Group||http://www.lloyds.com/~/media/lloyds/reports/emerging%20risk%20reports/solar%20storm%20risk%20to%20the%20north%20american%20electric%20grid.pdf||NASA||http://science.nasa.gov/science-news/science-at-nasa/2009/21jan_severespaceweather/||Washington Post||http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2014/07/23/how-a-solar-storm-nearly-destroyed-life-as-we-know-it-two-years-ago/||NASA|
|Riley et al 2012|
|bioterrorism||conflict||man made||a deadly microbe strain is developed as a biological weapon, causing a global pandemic||unlike natural diseases, bioengineered diseases could potentially kill everyone on Earth. the risk of a deliberately biological weapon release is currently low, but will rise as biotechnology gets better and cheaper.||in 2001, scientists introduced a gene to mousepox (the mouse version of smallpox) to make a 100% lethal virus that also killed half of vaccinated mice. scientists have created a form of bird flu (H5N1) that can be transmitted between mammals, raising fears it could trigger a human pandemic if it escapes from the lab.||4||3||4||4||5||2||The Conversation||https://theconversation.com/the-five-biggest-threats-to-human-existence-27053||Jackson et al 2001 (mousepox)||http://jvi.asm.org/content/75/3/1205.long||Nature (bird flu)||http://www.nature.com/news/specials/mutantflu/index.html||Bostrom 2002 (mice)||http://www.nickbostrom.com/existential/risks.html|
|loss of topsoil||environment||man made||deforestation and bad farming mean soil loses its integrity and fertility, and washes or blows away. plants cannot grow in the land left behind, which turns into desert.||serious, if unfashionable. we're screwed without soil. degraded soil means we could produce 30% less food over the next 20-50 years, when we need to grow 50% more food to feed a growing, increasingly meat-eating global population.||on current trends, we have about 60 years of topsoil left. |
half the world's topsoil has been lost in the last 150 years.
soil is being lost 10 to 40 times faster than it is being replenished.
|4||5||2||4||2||2||Cornell Chronicle||http://www.news.cornell.edu/stories/2006/03/slow-insidious-soil-erosion-threatens-human-health-and-welfare||BBC||http://news.bbc.co.uk/dna/ptop/plain/A2184473||WWF||http://www.worldwildlife.org/threats/soil-erosion-and-degradation||John Crawford, University of Sydney / TIME||http://world.time.com/2012/12/14/what-if-the-worlds-soil-runs-out/|
|combo-pocalypse||other||man made||various challenges in combination form a deadly chain of events that overwhelms the human species||very worrying. environmental, political and economic problems that we could survive if they occurred separately could set off an apocalyptic cascade that we did not survive. nanoterrorism is more likely in a world politically destabilised by climate change, for example.||a species-ending combination? |
+ resource depletion
+ nuclear war
WEF: 'This dynamic applies to governments, too,
where there is also a tendency for departments to argue for
attention to their own sector-specific risks rather than take a
more holistic overview of the risks of the greatest national
importance that may interact with and reinforce others if not
|World Economic Forum||http://www3.weforum.org/docs/WEF_GlobalRisks_Report_2014.pdf||Goux-Baudiment 2009||http://www.academia.edu/1536452/Tomorrow_will_die|
|climate change||environment||man made||human emissions and deforestation change the balance of Earth's atmospheric gases, warming the climate||potentially dire – sea level rise, extreme weather, food crop disruption. probably won't kill everyone off directly, but could spark terrible wars that might.||global temperatures in 2100, compared to preindustrial levels (IPCC projections) |
+1.5 lower end of estimates
+4.8°C upper end of estimates
1.5-4.8°C - IPCC AR5, Table SPM.1, p12 Summary for Policymakers. Scenarios for c.450ppm (1.5 degrees) and >1000ppm CO2 (4.8 degrees) by 2100. Median estimates.
|nanoweapons||technology||man made||atomically precise manufacturing means new, super-lethal weapons can be produced||very serious. nanotechnology is developing fast. once out there, will be difficult to regulate and will give humans spectacular power to kill each other. nanoweapons would be very dangerous in the hands of terrorists or cults. could cause rapid nano-arms races.||future nanoweapons? |
: smart poisons that seek out their victims
: 3D-printed nuclear weapons
: climate engineering tools
|4||4||3||4||5||3||Anders Sandberg in The Conversation||https://theconversation.com/the-five-biggest-threats-to-human-existence-27053||Bostrom 2002||http://www.nickbostrom.com/existential/risks.html|
|grey goo||technology||man made||microscopic nanotechnology machines mutate, spontaneously replicate and devour everything on Earth – or the Universe – turning it into so-called 'grey goo'||avoidable: we could avoid creating self-replicating nanobots, confine them to sealed environments, or build them so mutations would kill them. but accidents could still happen, and terrorists could build them maliciously.||assume a nanobot weighs 1 nanogram (ng) and takes an hour to replicate itself:|
after one hour: 2 nanobots weigh 2ng
after 2 hours: 4 weigh 4ng
after 48 hours: total weight is 148 kg, as much as a sumo wrestler
after 123 hours: weigh 5 septillion tonnes (5 followed by 18 zeros), as much as the Earth
|3||2||5||3 - revised to 1||5||2||The term was first penned by scientist Eric Drexler in his book "Engines of Creation" [source: Radford]. After 48 hours: (2^47)*10^-12 = 141 kg. Average weight sumo wrestler 148kg. After 72 hours: ((2^71)*10^-12) = 2.36bn kg. After 123 hours: ((2^122)*10^-12) = 5.317 x 10^24 kg. Mass of Earth = 5.9726 x 10^24 kg.||Anders Sandberg in The Conversation||https://theconversation.com/the-five-biggest-threats-to-human-existence-27053||Bostrom 2002||http://www.nickbostrom.com/existential/risks.html||NASA (Mass of Earth)||http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html||Web Japan (sumo)||http://web-japan.org/museum/sumo/about_su.html|
|resource depletion||environment||man made||key natural resources (oil, coal, metals, elements used in industry) become scarce because of overextraction and inadequate recycling. civilisation collapses.||a bad economic blow, but probably not a fatal one. several resources are becoming scarce – oil production may already have peaked – but more abundant or renewable alternatives often exist. or there's recycling. or the Moon.||resources at risk|
: rare earth elements (found in mobile phones, LCD TVs, wind turbines)
: tungsten (light bulbs, tools)
: antimony (batteries, flame-retardants)
|4||5||2||4||2||2||British Geological Survey Risk List 2012||http://www.bgs.ac.uk/mineralsuk/statistics/riskList.html||Guardian (oil production may already have peaked)||http://www.theguardian.com/environment/earth-insight/2013/dec/23/british-petroleum-geologist-peak-oil-break-economy-recession|
|asteroid impact||space||natural||a large asteroid or comet smashes into Earth or the Moon||a human race-destroying asteroid will likely approach us within the next few hundred thousand years. if we spotted it in time, we'd have a good chance of diverting it with a nuclear bomb. a much smaller asteroid would wreak havoc if it hit a city, though.||min. size an asteroid would have to be to wipe out humans: 1km across. |
how often an asteroid this large will collide with Earth: roughly every 500,000 years.
size of Tunguska asteroid that hit Siberia in 1908, felling trees within a 40km radius: 60m across.
how often an asteroid this large will collide with Earth: roughly every 300 years.
size of asteroid that possibly wiped out dinosaurs 66 million years ago: 10-15km across.
how often an asteroid this large will collide with Earth: roughly every 100 million years
|2||4||4||4||5||3||Anders Sandberg in the Conversation: 'Meteors could certainly wipe us out, but we would have to be very unlucky. The average mammalian species survives for about a million years. Hence, the background natural extinction rate is roughly one in a million per year.'||Popular Science magazine||http://www.popsci.com/science/article/2013-07/could-asteroid-impact-knock-moon-earth||The Atlantic||http://www.theatlantic.com/technology/archive/2011/11/what-if-a-large-asteroid-were-to-hit-the-moon/248129/||BBC (small asteroids hit all the time)||http://www.bbc.co.uk/news/science-environment-26325934||The Conversation|
|Bostrom 2002 (Tunguska size, K/T size, 1km diameter, nuclear bomb)||http://www.nickbostrom.com/existential/risks.html|
NASA (Tunguska asteroid every 300 years)
Planetary Science Institute (10km asteroid every 100my)
|gamma ray burst||space||natural||a stellar explosion within the Milky Way releases an intense burst of gamma rays, destroying the ozone layer and causing global cooling||very unlikely – a dangerous GRB should occur on average 2-3 times per billion years. all GRBs observed so far have originated outside the Milky Way, most billions of light years from Earth.||some scientists believe a GRB may have contributed to the End-Ordivician extinction on Earth, which killed up to 88% of species.||1||4||4||4||3||5||Melott et al 2004||http://arxiv.org/abs/astro-ph/0309415||Podsiadlowski et al 2004||http://arxiv.org/abs/astro-ph/0403399||Berkeley||http://astro.berkeley.edu/research/grbs/grbinfo.html||National Geographic||http://news.nationalgeographic.com/news/2009/04/090403-gamma-ray-extinction.html|
|death of the Sun||space||natural||the Sun expands into a red giant as it nears the end of its life, engulfing the inner planets, including Earth||the end of humanity in a billion years, unless we've migrated to other planets by then. Earth will become uninhabitable as the gradually heating Sun evaporates the oceans.||time until the Sun will become a red giant: 7.59 billion years. |
time until the heating Sun will evaporate the Earth's oceans: 1 billion years
|1||5||5||5||2||5||Universe Today||http://www.universetoday.com/12648/will-earth-survive-when-the-sun-becomes-a-red-giant/||Schroder and Smith 2008||http://arxiv.org/abs/0801.4031|
|death of the Universe||space||natural||the Universe comes to an end. everyone dies.||absolute but very, very distant. certain death for everything in the Universe, including us. but not going to happen for trillions of years.||Universe-ending theories|
Big Freeze: the Universe keeps expanding, becoming too cold to sustain life
Big Crunch: the Universe stops expanding and collapses into a black hole or another Big Bang
Big Rip: the Universe keeps expanding until matter is torn apart
|1||5||5||5||5||5||Wikipedia Chronology of the Universe||http://en.wikipedia.org/wiki/Chronology_of_the_universe||Universe Today||http://www.universetoday.com/11430/the-end-of-everything/||Wikipedia Big Freeze||http://en.wikipedia.org/wiki/Future_of_an_expanding_universe||Wiki Big Crunch||http://en.wikipedia.org/wiki/Big_crunch||Wiki Big Rip|
|Non-apocalypses: it won't end this way|
|supernova||space||natural||the Sun or a nearby star goes supernova||the Sun isn't large enough, and there are no stars close enough to damage us if they exploded||-||-||-||-||-||-||-||Universe Today||http://www.universetoday.com/107791/will-the-sun-explode/||i09||http://io9.com/5738542/earth-may-soon-have-a-second-sun||Discover Magazine||http://blogs.discovermagazine.com/badastronomy/2012/05/18/the-closest-supernova-candidate/|
|planet X||space||natural||a giant planet heads towards Earth, crashing into us or pulling us out of orbit||people have been looking for other planets in our Solar System for centuries. they've found seven, all orbiting the Sun nicely. none of them are heading straight for us.||-||-||-||-||-||-||-||Universe Today||http://www.universetoday.com/42450/planet-x/||Exoplanets.org||http://exoplanets.org/|
|polar flip||space||natural||the polarity of Earth's magnetic field weakens before reversing. a weaker field means more dangerous cosmic radiation hits Earth.||the Earth's poles flip regularly – every 200,000 years or so. the increase in solar radiation would be minor, nothing to worry about. compasses would point the wrong way, though.||-||-||-||-||-||-||-|
NASA: Another doomsday hypothesis about a geomagnetic flip plays up fears about incoming solar activity. This suggestion mistakenly assumes that a pole reversal would momentarily leave Earth without the magnetic field that protects us from solar flares and coronal mass ejections from the sun. But, while Earth's magnetic field can indeed weaken and strengthen over time, there is no indication that it has ever disappeared completely. A weaker field would certainly lead to a small increase in solar radiation on Earth – as well as a beautiful display of aurora at lower latitudes -- but nothing deadly. Moreover, even with a weakened magnetic field, Earth's thick atmosphere also offers protection against the sun's incoming particles.
Kroeger: Over the last several million years, the average time between reversals has been about 200,000 years. The last reversal was 730,000 years ago. Reversals probably take less that 5,000 years. Reversals of the field probably involve a period of time where the field weakens substantially and becomes disorganized (non-dipole), then reorganizes in the opposite polarity. People should wear lead underwear during a reversal, as the Earth's surface will be bombarded with a higher than normal amount of cosmic radiation!
|NASA||http://www.nasa.gov/topics/earth/features/2012-poleReversal.html||Glenn Kroeger, Geoscience, Trinity University||http://www.trinity.edu/gkroeger/geos1307/notes/earth.htm|
Apocalyptic predictions that didn't come to pass
|prediction||what actually happened|
|Nostradamus||other||man made||the "King of Terror" would come from the sky in "1999 and seven months", according to popular interpretations of the 16th century author||1999 passed without the King of Terror appearing||-||-||-||-||-||-||-||Wiki|
|doomsday cults||other||man made||the world would end in 1687, 1900, 2012...||the world is still going, for the time being at least||Doomsday cults that turned murderous |
: Charles Manson – ordered 7 murders in an attempt to start an apocalyptic race war he called Helter Skelter after the Beatles song
: Aum Shinrikyo – the leader of the cult behind the 1995 Japanese subway gas attack predicted Armageddon would occur in 1997. it didn't.
: Heaven's Gate cult – 39 of the group's members committed mass suicide in 1997 following the arrival of Comet Hale-Bopp
|Y2K bug||technology||man made||computer systems would crash following the change of date from 1999 to 2000||companies fixed the systems and all was well||-||-||-||-||-||-||-||Wiki||http://en.wikipedia.org/wiki/Y2k|