Mt wisely points out that the World Doesn’t End in 2100. Its a fair point, and one that is often forgotten. However… its one that I have come to increasingly downweight as time goes by. For two reasons. One is practical: it simply won’t work as a way of motivating people. If thats your best argument, the public won’t listen. And the public, being very impatient of depth, aren’t going to listen to anything but your best argument, if that. The second is that predicting societal and technological changes past 100 years is impossible. Even 100 years is pushing it, but further is just too much.