I’ve just been reading up on the near-Earth asteroid Apophis and been thinking about what would happen if it hit the Earth.
Imagine, if you will, that we’ve become entirely happy that it will miss, so there’s no need to do anything. Then, at a very late stage, its trajectory shifts slightly. Maybe it gets hit by a solar flare, maybe some doomsday cult does something, or maybe the measurements were wrong, it doesn’t really matter. But it’s too late to do anything and Apophis impacts the Earth.
Now, how would humanity react to it, both immediately and in the longer term?
I’m thinking that while a deep oceanic impact might have a greater intial impact due to tsunamis, a land impact - 800 MT - would be about the same as the eruption of Tambora in 1815 which caused widespread bad weather and crop failure. Humanity survived that, but the world will have about 9x the population. Will we see widespread war or will we decide to let people starve? The Americas will be able to feed themselves (unless hit), but Britain, India, and China will be hit very hard.
And what about an oceanic impact? Would an impact in the north Pacific cause a tsunami that would wash away California?