When the Mexican volcano El Chichón erupted in 1982, it killed 1,900 people and shocked many who had believed it to be extinct. Unknown to observers at the time, it also kick-started a chain of environmental changes. Using data from nearly 6,500 meteorological stations, a new study has found that numerous biophysical indicators – including the temperature and salinity of the oceans, the pH level of rivers, and the amount of ice and snow in the cryosphere – experienced significant changes over the five to six years following the eruption, travelling around the world from west to east. Crucially, it also saw rapid warming, as temperatures bounced back strongly from the initial cooling effects of the eruption.
‘Our work contradicts the perceived view that major volcanic eruptions lead to a cooling of the world,’ says Phillip Reid, Professor of Oceanography at Plymouth University’s Marine Institute. ‘We demonstrate that a major change took place in the world that involved a step change and move to a new regime in a wide range of Earth systems. It looks as if global warming has reached a tipping point where the cooling that follows such eruptions rebounds with a rapid rise in temperature.’
This article was published in the January 2016 edition of Geographical magazine.