The Earth can take care of itself. It's ourselves that we have to worry about. The same ecological mechanisms that keep the earth capable of sustaining life will ensure that any real danger tio the ecosystem, and that includes us. Oh sure, it might set life back on the planet by a couple of eons. Might lose everything more complex than a tube worm. But the Earth continues. Life is freaking stubborn, and the Earth is no exception.
I'd also like to point out that the bacteria rule the world. They have control over everything from the salinity of the oceans to the content of our atmosphere. They even control our bowel movements!
Bow to the ruleing elite.