You can now see an excellent visualization of global catastrophic risks estimates produced in the Ragnarök series here.
No single disease currently exists that combines the worst-case levels of transmissibility, lethality, resistance to therapies, and global reach. But we know that the worst-case attributes can be realized independently. For example, some diseases exhibit nearly a 100% case fatality ratio in the absence of treatment, such as rabies or septicemic plague. The 1918 flu has a track record of spreading to virtually every human community worldwide. Chickenpox and HSV-1, can reportedly reach over 95% of a given population.
An informal survey at the 2008 Oxford Global Catastrophic Risk Conference asked participants to estimate the chance that disasters of different types would occur before 2100. Participants had a median risk estimate of 0.05% that a natural pandemic would lead to human extinction by 2100, and a median risk estimate of 2% that an “engineered” pandemic would lead to extinction by 2100.
Moreover, previous literature has found that casualty numbers from terrorism and warfare follow a power law distribution, including terrorism from WMDs. Millett and Snyder-Beattie have performed a naive power law extrapolation to estimate the chance of an existential biological disaster:
Past studies have estimated this ratio for terrorism using biological and chemical weapons to be about 0.5 for 1 order of magnitude, meaning that an attack that kills people is about 3 times less likely () than an attack that kills people (a concrete example is that attacks with more than 1,000 casualties, such as the Aum Shinrikyo attacks, will be about 30 times less probable than an attack that kills a single individual). Extrapolating the power law out, we find that the probability that an attack kills more than 5 billion will be or 0.000014. Assuming 1 attack per year (extrapolated on the current rate of bio-attacks) and assuming that only 10% of such attacks that kill more than 5 billion eventually lead to extinction (due to the breakdown of society, or other knock-on effects), we get an annual existential risk of 0.0000014 (or ).
In the first part of the Ragnarök Question Series, we asked the question If a global catastrophe occurs, will it be due to biotechnology or bioengineered organisms? Now it is asked,
Given that a biological global catastrophe occurs that results in the reduction of global population of at least 10% by 2100, will the global population decline more than 95% relative to the pre-catastrophe population?
The question resolves positive if such a global biological catastrophe does occur, and the global population is less than 95% of the pre-catastrophe population. The question resolves ambiguous if a global biological catastrophe that claims at least 10% (in any period of 5 years or less) does not occur. The question resolves negative if a global biological catastrophe failure-mode induced global catastrophe occurs that claims at least 10% (in any period of 5 years or less) but the post-catastrophe population remains above 5%.
A biological catastrophe is here defined as a catastrophe resulting from the deployment biotechnologies or bioengineered organisms (including viruses) that claims at least 10% in any period of 5 years or less before 2100. Moreover, the catastrophe must be generally believed very unlikely in a counterfactual world with little or no biotechnological interventions but otherwise similar to ours.
This question is part of the Ragnarök Question Series. Check out the other questions in the series:
Also, please check out our questions on whether a global catastrophe will occur by 2100, and if so, which?:
All results are analysed here, and will be updated periodically.