Prioritization of Different Kinds of Natural Disasters and Low-Probability, High-Consequence Events

抄録

In the history of terrestrial lifeforms, several different kinds of natural disasters can be classified in biological history since the Phanerozoic period. The most serious disasters can be classified as (1) volcanic disasters, (2) asteroid impacts, and (3) climate disasters, in reference to the root cause of low-probability, high-consequence (LPHC) events. However, on a shorter timescale, mankind is more vulnerable to frequent disasters, such as (i) large floods, (ii) epidemics, (iii) earthquakes, (iv) tsunamis, and (v) small-medium scale volcanic eruptions. These are known as high-probability, low-medium-consequence events (HPLC). LPHC occurrences have a very low probability of occurring, but they would have catastrophic consequences. HPLCs occur more frequently, with most of them having decadal frequency. They cause local fatalities, but they are never global in scale. In this study, these events are classified and evaluated based on the potential risk for human civilization. We also discuss how to incorporate different considerations related to prioritizing different disasters, focusing on whether insurance mechanisms can be applied or not.