[M-ZZ45] プラネタリーディフェンス、我々は何をすべきか

[MZZ45-01] 異なる自然災害と低頻度・巨大損失事象の優先順位付けにおける小惑星衝突のリスク評価

*山敷 庸亮¹、藤田 萌² (1.京都大学大学院総合生存学館、2.あいおいニッセイ同和損害保険)

キーワード：低頻度・巨大損失事象、小惑星衝突、保険

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. In this context, asteroid impact only appear very-long-term LPHC but dissapears in our shorter timescale, despite of the large and catastrophic potential risk into our civilization. We tried to validate such risk in order to encourage explicit consideration in modern insurance system.