Magma carto

By The Data Team

LARGE volcanic eruptions do not merely devastate the areas surrounding them. They also change the climate around the world. This is because they inject tens of millions of tonnes of sulphur-dioxide gas into the stratosphere, where it spreads around one or both hemispheres and eventually forms a veil of tiny sulphate particles which scatter incoming sunlight, thus reducing the amount that gets to the surface. These volcanic veils can be detected in cores of polar ice—the sulphate particles eventually settle back down to the surface. That allows geologists to supplement the necessarily patchy records they build up by studying individual volcanoes with an independent record of eruptions that have been large enough to change the climate.

Our briefing, marking the 200th anniversary of Tambora—the most powerful eruption in modern history—assesses the risk of similar events happening again, at almost any time.