Professor Hans Joachim Schellnhuber (shown) wants to take us back to the Stone Age — literally. In a March 15 interview with the German newspaper Deutsche Welle, the German physicist declared that global warming is so serious that not only must we all give up the use of coal and our internal combustion vehicles in the next 13 years, but we must also ditch concrete and steel — for “wood, clay and stone.” If we don’t do this, along with other drastic measures, we are headed toward planetary warming of “4, 5, 6 or even 12 degrees,” he claims. This would bring, he...