Besides, Humans != TheWorld. This planet is going to spin even if we--arguably the biggest issue this planet ever had--are gone. There is this old joke. Two planets meet and have a chat. "So, how are you?" "Well, not good." "Why?" "I have homosapien!" "Don't worry, this will pass."

So, no worries, the world is not going to end.

And if humans manage to ruin their living conditions so badly that we end up dying out, evolution has just made another important step. After all, it is not like we deserve to survive.