„We’re just on a trend line where on a long enough time scale, I can 3D print a nuclear weapon in my house. On a long enough time scale, I can take a synthetic biology lab in my room and create a weaponized virus that combines the most virulent features of smallpox and the longevity of AIDS and spreads like the flu.”
There is something in the neighborhood of 300 mass shootings in the USA each and every year. That's something in the neighborhood of 3rd of the supply of worlds mass shootings. (about 1000 a year). A very high percentage of the rampage killers are suicidal. This type of person detonates with some regularity. In the future when technologies advance and proliferate these type of people will have access to some terrifying capabilities.
In China, there was many mass killings. However, guns are illegal there and the weapon that killers had was a knife or hammer. This way the average number of deaths per year is way lower.
Naval says that for him a most likely answer for the Fermi Paradox is that the civilization that achieved advanced enough technological state blows itself out.
Naval says that synthetic biology is the most immediate thread.
Bioweapons are maybe the largest thread. There is a super deadly and a highly infections virus locked up in some research institution in the Netherlands. The number of DNA modifications that differentiate it from a common virus can be written down on one post-it note.
Super or General AI is very dangerous because we won’t have time to develop a civilizational immune response. Passing the threshold between General AI to Super AI might be immediate (somebody will invent it and then AI will start compounding its own knowledge and skills and start improving itself. That said Naval believes ASI or AGI are not gonna be developed for some time now (there are many smart people disagreeing with this though))
Drones also will be a huge thread. There was a flock of geese that run into a plane’s engine and take it down (the 2015ish landing on the Hudson River in New York)
Naval thinks that eventually, commercial air travel will come to an end because weaponized drones will be too prevalent. There was a Gatwick Airport incident in December 2018 when a mysterious drone disrupted over 1,000 flights.
If you think this is a sci-fi speculation you might be under Amara’s Law illusion: We overestimate technology in the short run and underestimate technology in the long run. This is why crypto and dot-com bubbles might have happened.