SO OFTEN TODAY we hear campaigners and politicians say the real problem is simply that promises have not gone far enough. Indeed, since the signing of the Paris Agreement it has become more and more fashionable to suggest that entire nations should go net-zero; that is, stop contributing carbon dioxide to the atmosphere by 2050 or sooner. More than sixty countries have promised to achieve carbon neutrality within the next thirty years. The biggest emitters—China, the United States, and India—are not among them. The biggest nations that have made the pledge are the UK, France, and Germany.
