Although it is well-known that volcanic eruptions can alter the climate, can humans-made climate change affect volcanic eruptions? Curiously, it appears that the answer is yes.
The sulphuric acid cloud that formed from the eruption of Mount Pinatubo in the Philippines in 1991 lowered global temperatures by 0.5C over a period of more than one year. Although they are very rare, these explosive eruptions can occur only once or twice a year on average. However, their cooling effect could be up to 15% as the world gets warmer.
This is because the stratosphere, the second layer of Earth's atmosphere, will be warmer than the rest and will be less stratified. According to Nature Communications research, this will lead to sulphate aerosols spreading faster and further around the globe, blocking more solar radiation.
In a warmer world, mildly explosive eruptions like the one in 2020 at Taal volcano in Philippines may see their cooling effect decrease by up to 75%.
This is because the tropopause, the boundary between the first layer and second layers of atmosphere, will rise. It's less likely that small and medium volcano plumes will reach stratosphere and more likely that aerosols from the lower atmosphere will be rapidly washed away by snow and rain.
