How would that start fires?
The tremendous kinetic energy of an object hitting the atmosphere
All that energy is converted to heat - the thermal pulse resulting is similar to that of a nuclear blast
You’re right, of course. Given a sufficiently wide distribution of large-enough fragments, it could even ignite 10% of the world’s land area. It wouldn’t be like a scaled-up version of throwing a big rock into a pond, which was what I was driving at with my earlier post.