Volcanoes and climate change – how do they connect?

Monitoring the interaction of volcanic eruptions with the atmosphere is increasingly important in a changing climate

It was around Christmas last year that the Cumbre Vieja volcano stopped spitting lava on the Spanish island of La Palma, bringing some relief to the locals after more than 85 days of eruption and €1 billion in damages. But in 2021 Cumbre Vieja was not the only volcano making headlines with its massive outburst. Across the world, from Kamceatka to Reunion and Guatemala, and from Iceland to Sicily, several volcanoes fired up into sizable eruptions, adding to the list of extreme events affecting lives and economies.

Increasingly, when extreme events occur, be they wildfires, typhoons, or floods, they stir discussions about the role of climate change in making natural hazards more frequent and/or intense. But is that the case for volcanic eruptions too? Can we tie volcano behaviour to climate change? And if so, why does it matter?

Volcanoes do interact with the climate through what they inject into the atmosphere during eruptions. Eruptions produce big amounts of gas, particles (known as aerosols), ash and metals, temporarily altering the climate at a local, regional, or even global scale.

“Large volcanic eruptions in the past have changed global climate directly and by reinforcing other processes,” says Dr. Santiago Arrellano, researcher at the Department of Space, Earth and Environment at the Chalmers Institute of Technology. An eruption’s effect on the climate depends on the location, altitude, amount, and composition of the material spewed, explains Dr. Arrellano. For example, tropical eruptions will have a bigger impact than those in upper latitudes, as air from the tropics travels more widely, and can carry