The top five greenhouse gas–emitting nations—the U.S., China, Russia, Brazil and India—collectively caused $6 trillion in global economic losses between 1990 and 2014, according to a recent study of available data. And those losses haven’t been felt equally. Dartmouth College climate scientists Christopher W. Callahan and Justin S. Mankin used climate models to determine how much of the planet’s warming could be attributed to each country’s emissions and calculated what those emissions have cost every other country. The scientists…