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Global Risk: A Quantitative Analysis
Thomas McCabeRensselaer Polytechnic Institute
[email protected]@rpi.edu
Nuclear war A full-scale nuclear war in 1988, during the
height of the Cold War, could be expected to kill around 1,850,000,000 people, or 36% of the world's population.
Source: ”The Effects of a Global Thermonuclear War”, by Robert Johnston
Nuclear war WWII Holocaust Iraq war Bhopal 9/110
200000000
400000000
600000000
800000000
1000000000
1200000000
1400000000
1600000000
1800000000
2000000000
Casualties
Nuclear war WWII Holocaust Iraq war Bhopal 9/110
1
2
3
4
5
6
7
8
9
10
Casualties (order of magnitude)
Smallpox epidemic In spite of vaccinations, smallpox killed 300
to 500 million people from 1900 through 1980.
A new smallpox epidemic today could kill up to two billion, or 30% of the population.
Sources: ”Smallpox: The Fight to Eradicate a Global Scourge”, by David Koplow
”The Nightmare of Bioterrorism”, by Laurie Garrett
Asteroid strike An asteroid two kilometers across hitting
Earth would cause massive tsunamis, fires, etc., and would kill around one to two billion people.
Such a strike occurs, on average, once every million years.
Source: Tsunami from Asteroid/Comet Impacts, by Michael Paine
Extinction risks Genetically engineered supervirus Global climate runaway feedback loop Nearby gamma ray burst Nearby supernova Environmental collapse Simulation gets shut down Rogue artificial intelligence Molecular nanotechnology accident Particle accelerator accident
Risk priority equation
P = I * L * R / E
P = risk priority I = impact of the risk L = likelihood of the risk R = how much the risk is reduced E = effort to reduce the risk
Priority of car crashes Impact: $100,000 Likelihood: 10% = 0.1 Risk reduction: 50% = 0.5 Effort = 10 hrs.
Risk priority = 100,000 * 0.1 * 0.5 / 10
= 500 $/hr.
Laplace's rule of succession Given a uniform prior distribution over
probabilities, if something has not happened during each of N independent tests, the probability that it will happen during the next test is 1 / (N + 2).
GRB probability There are 100 billion galaxies, and GRBs
happen around a hundred times a year, so the chances of one happening in our galaxy this year is around one in a billion.
Source: Deadly astronomical event not likely to happen in our galaxy, study finds, press release by Oregon State University
GRB probability If a GRB does happen in our galaxy, it would
have to be within three thousand light years to cause serious damage.
The galaxy is around a hundred thousand light years across, so the odds of this are roughly 1:250, for a combined probability of 1:250,000,000,000.
Inductive GRB probability We know that all life hasn't been killed by a
GRB in the past four billion years, so by Laplace's rule, the odds of us being killed next year are 1 / (4,000,000,000 + 2), or 1:4,000,000,002.
Nuclear war probability Martin Hellman's rough estimate: 1% per
year, or around 10% per decade.
Inductive estimate: 1 / (59 + 2) = 1:61, or around 1.6%.
Source: Risk Analysis of Nuclear Deterrence, by Martin Hellman
Chance of smallpox outbreak To my knowledge, no studies have been
done on this.
Inductive probability: 1 / (29 + 2) = 1:31, or around 3.2% per year.
Asteroid impact frequency
Risk mitigation Even if two risks have the same impact and
probability, one may be much easier to prevent.
Technological risks are always easiest to prevent when they are new, and the technology is still being developed.
Molecular nanotechnology
Molecular nanotechnology Ability to manufacture large numbers of
weapons at minimal cost, and destroy or conquer the world.
An MNT accident may wind up consuming the entire planet, including us, in a search for more raw materials.
Orders of magnitude
Comparison of relative risk
List of dangerous machines Lawnmower
Boeing 747 passenger jet
List of dangerous machines Lawnmower
Boeing 747 passenger jet
Quartz wristwatch
Saturn V rocket
Availability heuristic People tend to judge how dangerous things
are by how often they hear about them, either personally or through the media.
Popular estimates of causes of death are highly correlated with selective newspaper reporting.
Source: Newspaper coverage of causes of death, by Barbara Combs and Paul Slovic
Number of Google News hits Grey goo nanotechnology: 527 ”Asteroid impact”: 1,690 LHC destroy world: 7,880 Smallpox outbreak: 9,940 Anna Nicole Smith: 66,600 ”Nuclear war”: 84,700