Maybe. I hate the contrary nature of these discussions. If this was real life I’d get you a coffee.
I don’t think we can kill the planet. Short of Nuclear Annihilation, we can however probably put a dent in its ability to sustain people. Maybe even make it harder for Mammals to survive at all. Maybe.
But it has taken very large lumps before, and it came back, life found a way. It will again.
We can’t kill the world.
We can however kill ourselves.