Well, debono, the scientists are telling us that, at the macro level, the changes above +1.5C are preventable and avoidable if action is taken. They also told us twenty years ago that action taken then would have prevented the bulk of the +1.5C rise but we collectively chose to not take that advice. Personally, I think they are pretty accurate in their models and interpretations out to at least 50 years.
I'm not sure that I understand the evolution question. Most of the changes in humans you list are known to be the result of better nutrition and disease prevention on the development of the human body. Organisms can definitely evolve to cope with higher temps but for most organisms the current rate of change is so much faster than the hundreds of generations needed for that to occur that they will either learn to cope (not evolve) or reduce their range and numbers.
