Humans have an amazing ability to adapt. No matter what we do now, there WILL be a hot period, maybe even as hot as the Cretaceous period. After that there WILL be an ice age where a sizable portion of the Northern Hemisphere will be frozen and enormous glaciers may form and gouge a completely new terrain. The human politicians and scientists who are fighting about this now will be long dead before any of them are proven right or wrong. Islands will be submerged in water, new land masses will be uncovered by changing sea levels. By that time humans will have already accepted the climate and environment they live in as normal, and it will not change significantly during their lifetimes. Living today with fear and anger over what the planet will be like centuries from now is as irrational as ancient humans getting pissed because mammoth fur is itchy to wear and it got damn cold.