New findings on the global cooling of 1627 BC

Aniakchak caldera on the Alaska Peninsula with a diameter of around 10 kilometres. Together with the Aleutian Island chain, this region is one of the most active volcanic regions in the world. Wikicommons / M.Williams_Alaska_National_Park_Service - An interdisciplinary study, in which the University of Bern played a major role, sheds new light on two extreme volcanic events and a subsequent global cooling in antiquity. With the help of a highly precise analysis of volcanic ash and sulphur in ice cores from Greenland and Antarctica, it became clear that the global cooling around 1627 BC was not attributable to the Thera volcano in Santorini, as previously assumed, but to a volcano in distant Alaska. The smallest droplets of sulphuric acid, which reach heights of up to 40 kilometres in the stratosphere as a result of explosive volcanic eruptions, can lead to sudden climate shocks with far-reaching consequences. This was already the case in ancient times, when probably the most famous volcanic eruption in history occurred around 1600 BC, the eruption of Thera on the Aegean island of Santorini, an important ancient trading centre in the Mediterranean. Far less well known is a second volcanic eruption around the same time: the eruption of Aniakchak II, a remote volcano in the Aleutian Range in what is now Alaska.