That's just humans though, plenty of life will go on living and they will probably be better off without a global apex predator in their way. That will be the true bright future for life on Earth. Maybe we'll eventually manage to better ourselves and solve the climate problems we're facing too, time will tell.

One thing though, some sections of the planet will become uninhabitable for humans, not all though. People have been living in the scorching heat of the desert for thousands of years, if the average summer temperature closer to the poles increases to 27 instead of 22, people will manage to survive there, worst case they'll adopt a nomadic lifestyle again.