In June 1991 the Philippine volcano, Mount Pinatubo, blew its top in spectacular fashion, producing one of the greatest volcanic eruptions in the 20th Century. It is well known that this eruption, which killed around 800 people and left 10,000 homeless, ejected so much dust into the atmosphere that it had a major effect on climate, depressing global temperatures by around 0.5°C for a couple of years. But what is less commonly known is that if Typhoon Yunya hadn’t coincided with the eruption, the impact could have been significantly worse.

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Along with all the magma and ash, vast quantities of hydrogen chloride were pumped out of Pinatubo. Had this hydrogen chloride reached the stratosphere it would have initiated chemical reactions with chlorine (which is increased thanks to all chlorofluorocarbons – CFCs – we have pumped out) and massively thinned Earth’s ozone layer. But luckily Typhoon Yunya powered its way through the eruption plume and washed most of the hydrogen chloride out before it got anywhere near the stratosphere.

Next time we might not be so lucky. New research suggests that future Pinatubo-esque eruptions would likely cause serious thinning of the ozone layer, having a significant impact on skin cancer rates, livestock mortality and crop yields. “The implications for surface life on Earth from such a future eruption could be profound,” the scientists write in Geophysical Research Letters. And even though we are doing a good job of reducing CFCs in the ozone layer, the study showed that short-lived bromine (produced by marine plankton and micro-algae) will still facilitate this dramatic ozone thinning reaction in the stratosphere for decades to come.