The deathrates from infectious diseases follow a power law with a very low exponent. In layman’s terms: there is a reasonable possibility for a plague with an absolutely huge casualty rate.
Have you taken into account the cutting criticisms from Cosma on the bogosity of many power-law claims?
Do you have any examples of a species rendered extinct by a plague in nature? As far as I know, there are no known natural evolutionary paths to produce a super-plague like this:
anything that combined the deadliness and incubation period of AIDS with the transmissibility of the common cold.
Some people are genetically immune to AIDS, such transmission would rapidly select for that resistance in humans, while selection on the virus would reduce lethality (losing hosts). Also, HIV has a long incubation period because it is not replicating and killing cells at the rapid rate of the common cold, the tradeoffs here are real.
We’ve had close calls in the past: the black death killed around half the population of Europe, while Spanish Influenza infected 27% of all humans and killed one in ten of those, mostly healthy young adults.
People were suffering from malnutrition, poor sanitation, lack of broad-spectrum antibiotics and antivirals, lack of vaccination tech (to deal with both the flu and simultaneous or opportunistic infections). The Spanish Flu did its damage disproportionately to poor countries, while rich countries got by with a small fraction of the fatality rate.
Today the world is much richer, better fed, and otherwise protected than in 1918-1919.
The FHI survey of global catastrophic risks conference attendees assigned a median probability of 0.05% to a natural pandemic killing off humanity. I would assign a higher existential risk than direct extinction risk, on the basis that social collapse might be irrecoverable, but this is a small x-risk compared to artificial diseases.
Do you have any examples of a species rendered extinct by a plague in nature?
We might be observing one right now.
The FHI's mini advent calendar: counting down through the big five existential risks. The fourth one is an ancient risk, still with us today: pandemics and plagues.
Pandemics
Current understanding: high
Most worrying aspect: the past evidence points to a risky future
The deathrates from infectious diseases follow a power law with a very low exponent. In layman’s terms: there is a reasonable possibility for a plague with an absolutely huge casualty rate. We’ve had close calls in the past: the black death killed around half the population of Europe, while Spanish Influenza infected 27% of all humans and killed one in ten of those, mostly healthy young adults. All the characteristics of an ultimately deadly infection already exist in the wild: anything that combined the deadliness and incubation period of AIDS with the transmissibility of the common cold.
Moreover, we know that we are going to be seeing new diseases and new infections in the future: the only question is how deadly they will be. With modern global travel and transport, these diseases will spread far and wide. Against this, we have better communication and better trans-national institutions and cooperation – but these institutions could easily be overwhelmed, and countries aren’t nearly as well prepared as they need to be.