It's hard to think about these potential calamities. Any given pandemic is unlikely to be on the scale of 1918. But the next big one will come, eventually. Any given asteroid strike is unlikely to be on the scale of a Yucatan. But the next big one will come, eventually. And the fact that there were so many small pandemics, impacts and so on will be used as evidence by Naysayers that there's nothing to worry about. And Doomsayers will continue to classify each potential calamity as uniquely dangerous in order to gain leverage.