JOHN VOELCKER – The industrial revolution that began around 1750 was powered in large part by coal, and the carbon-rich fuel had 200 good years after that. By the middle of the last century, however, serious studies had begun of its deleterious effects on human health—and that was before the climate-change impact of human emissions of carbon dioxide became known. Transportation will slowly electrify over the coming decades, while coal’s share of electric power generation will wane worldwide.