One of the frustrating things about the current presidential election is that neither candidate is saying much about global warming. I have seen some doomsayers claiming that global warming and the associated oceanic acidification will mean the end of civilization as we know it, that the number of people the planet can sustain will be drastically reduced. I realize that any discussion is going to involve some conjecture, but is there anything close to a scientific consensus on how serious things are going to get based on the current state of affairs, if we assume that some measures will be taken to reduce greenhouse gas emissions?