Ancient Global Dimming Linked to Volcanic Eruption Ker Than for National Geographic NewsMarch 19, 2008 A "dry fog" that muted the sun's rays in A.D. 536 and plunged half the world into a famine-inducing chill was triggered by the eruption of a supervolcano, a new study says. The cause of the sixth-century global dimming has long been a matter of debate, but a team of international researchers recently discovered acidic sulphate molecules, which are signs of an eruption, in Greenland ice. This is the first physical evidence for the A.D. 536 event, which according to ancient texts from Mesoamerica, Europe,...