There is more than enough difference between people as to be separate species. Most have more in common with chimpanzees than the top 3% in intelligence.
Two disasters are coming, the first is the population crash where the cities will get hit hardest, and survival will depend on remoteness and cooperative village living.
Hitting more and more will be malevolent climate change, with natural reactions already at tipping points that will extend to worsening conditions for hundreds of years. The perhaps a few areas, by luck of geography will be less hit, and many people will go to underground living. This disaster will destroy support ecosystems, and the change will be faster than most life can adapt. It will be up to several million years before conditions are again similar to this interglacial epoch. This Anthropocene Epoch marked by extinction of over 3/4s of species, but will any future paleoanthropologist or geologist even see it in the rock layers?
How long will humans last underground or in less grievously hit areas? Will these less badly hit areas stay that way? How long will underground nuclear reactors provide power for grow lights?
Will people last for more than a few hundred years? Will people be around when the last of the plastic on land and in the oceans finally breaks down in 50,000 years? Will the ecosystems and species that can adapt in time and survive, be helpful for human survival?
Our extinction is not 100% certain, but close.