How long can humans survive on earth? This is a question that many of us want to know, and i believe that we do not want to wake up to a "Purgatory" Like venus, and hope that the earth can remain alive forever, so that we humans can continue and our generations can survive on earth forever. If the earth's environment were to change drastically and become an extremely hot planet like venus or mercury, then naturally everything in the world, including humans, would not be able to exist.