We know the man has been pumping millions of tons of greenhouse gases into our atmosphere for decades.<quoted text> There is a difference between reality and fairy tales. The technology is here to do everything posted and a lot more. Speculation is just that, guessing. The world has dealt with a lot worse and will deal with a lot more. It will still be spinning around the sun long after we aren't even a memory.
Voyager I has left the solar system. It will be 80,000 years before it even gets close to another star. Mankind most likely will be extinct by then. Can you grasp that?
What is insane is to think it doesn't matter.
They used to think that dumping garbage & sewage into the oceans wouldn't matter.