In terms of the various models used for simulation, I am somewhat skeptical of their efficacy for predictions. The reason is that simulations are based on parameters that are defined by the humans in charge. In essence, they can load the model to be favorable to their outlook. I am generally lean away from the "humans are evil" point-of-view that seems to drive the topic due to what others have alluded to - politics, money, and the attendant social engineering. Part of my doubt rises from the experience of the 1970s when we all were warned of the impending doom of a coming ice age. Well, that didn't happen. So, I'll continue to look with doubting eyes on the whole situation.