Wall Street Journal: Here’s a thing you don’t see very often: the head of one of the world’s dirtiest industries making common cause with climate-change campaigners. Lars Göran Josefsson is chief executive of Vattenfall AB, Europe’s fifth-largest electricity producer. His company is hardly the cleanest on the planet: Four of its plants feature in the dirty 30, a list of Europe’s biggest carbon-dioxide emitters, compiled by the European Union’s executive branch. But that hasn’t stopped Mr. …