New York Times: Tim Jackson, professor of sustainable development at the University of Surrey in Britain, uses a nifty back-of-the-envelope calculation to underscore the challenge of giving the worlds poor a shot at prosperity while preventing a global climate disaster. Lets accept, he proposes, that citizens of developing nations are entitled to become roughly as rich in 2050 as Europeans. Lets take note that the world will be home to more than nine billion people by then. What would it take, then, to prevent...