As it becomes obvious that there will be no rapid decarbonization (not, at least, on the scale needed to avoid a global climate catastrophe) unless “the rich” pay the costs of that rapidity, the question of who is rich, and how rich, is taking on a strange new importance. Which is why we like this little calculator. The data behind it, by the way, is taken from the work of Branko Milanovic, whose new book Words Apart: Measuring International and Global Inequality sets the gold standard, when it comes to, well, measuring international and global inequality.