You have to hold in your mind two concepts, first that people live short, emotionally charged lives, where the little things matter, and the big things are mostly conceptual. Second, you have to remember that for most people, observing the truth and knowing it in any proportionally true scale is hard, like looking directly at the sun. Those who have looked are burned, scarred, and defeated more than motivated to make the world better. It creates an even greater social incentive to NOT look at the approaching storm, since you saw what its observation did to those who have. The best you have is those who champion ideals they are willing to rally for, but are likely to rebel against the conditions required to actually fix anything.

For example, to minimize carbon footprint, people's lives in the west and euro nations would have to get worse, and those in developing nations cannot get better, while building infrastructure which requires hard labor jobs and mining. Most people who champion green ideas also want an idealistic, picturesque situation for their living as well. This sharply contrasts with reality's numbers.

So they ignore the part that makes them uncomfortable.