Again, I hope your right. The Earth has not always been a place where humans can live, and there is no logical reason to believe it will support human life in the future.
How far back in history do you have to go to find a time when the Earth couldn't support human life?
If I recall correctly, CO2 concentrations were pretty darn high when the dinosaurs where walking around. There were no people around then, but I don't see any reason why we couldn't live in a much warmer, wetter world.
There is strong evidence its exactly that that killed the dinosaurs.
http://blogs.discovermagazine.com/80beats/2011/07/25/did-methane-cause-the-mass-extinction-that-made-way-for-the-dinosaurs/
You got it backwards. The dinosaurs came after the mass extinction of other species.http://blogs.discovermagazine.com/80beats/2011/07/25/did-methane-cause-the-mass-extinction-that-made-way-for-the-dinosaurs/
Which is kind of my point: if there IS a mass extinction event, then that sucks for the species that go extinct. But new species will arise that are well-adapted to the new climate. And we humans are a pretty darn adaptable species...