I think this sort of view is naive and wildly optimistic. You picture the Earth as some sort of self-correcting organism that will extinguish us if we mess it up. It won't. You comically underestimate our resilience. No matter what the Earth does, we humans will figure out how to cling to life, and when push comes to shove, we don't give a fuck what we destroy. We will strip every cubic centimeter of soil, water, fish and fowl when it suits us, and still, we will find a way to survive on the barren rock. We can drop several thousand nuclear bombs, make the planet an ashen hell, and bounce back far faster than all the other creatures that our bombs destroyed. (Studies were done in the cold war...) The reason why our environment seems powerful relative to us is because we're relatively comfortable now, so we don't feel a strong urge/need to get up and destroy it. You have never seen a humanity whose survival is threatened. Let's hope nobody ever will, because that would be an ugly thing. You think we'll shuffle off and Earth will forget about us in time. In reality, I suspect that of all the species that are visible with the naked eye, we will be among the last to go extinct. If the Earth is a steaming radioactive death ball, we will build cities under the sea. (A much friendlier place to live than Mars.) When the seas boil off, we will move into temperature-regulated caverns underground. Think about it this way: Of all the millions of terrestrial species, which has the highest chance of actually being able to have a self-sustaining colony on Mars? Yeah, the answer is humans. That's how fucking tough we are. We can survive even on an otherwise lifeless rock. Anyone who thinks that a difference of 6C poses an existential danger to humanity is silly. Even a rise of 20C would sill leave Earth by far the most human-habitable place in the solar system. Our existence is not in danger. It's everything that lives alongside humanity that's facing the real danger.