''The fact that CO2 levels were considerably higher and that all species thrived says a lot.''
what do you think is going to happen when some large groups of humans 'thrive' and others don't?
what do you think is going to happen when some locations become more viable and others less?
do you think that humans will be like other mammals and happily (mostly) just move across large distances and plonk themselves in new territory?
and that's without even thinking about if climate reaches a tipping point where the Atlantic conveyor stalls - which, we know full well what happens when that happens
and which might be happening a hell of a lot sooner than when we were hoping that it might happen
if you think that humans are going to go happily with mass+++++++ migration - then, I suggest that you think again
