The fact that this is news to you is a clue that perhaps you know less about this subject than you think you do.
Hint: that means I won.
You claimed that the ecosystem "didn't survive" the Chicxulub event because there were different organisms afterward. I pointed out that by that "definition" the ecosystem has never "survived", because it has been in a state of constant change since day one.
Rather than responding to this, you just got nasty.
I repeat: I win. Sorry.
The question is, what do those changes mean for individual organisms? Because that's what you and I are.
Changes to the climate and ecosystem are like changes to velocity. Whether the change is good or bad for people depends on the magnitude and direction.
I do think that your focus on who is "winning" an imaginary Internet slap fight is detracting from your understanding.
"What do you think it's going to be like when about a billion people have to migrate inland due to sea level rise?"
Considering that even the worst-case doom-crying scenarios issued by the IPCC predict a sea level increase of the order of 1 meter over the period of a century (i.e., ~1 cm per year), your (and Hollywood's) suggestion of rioting mobs fleeing the tsunami-like rising ocean is just not based in reality.