Volcanoes can dramatically change nearby environments and the Earth's climate through eruptions. In 2010, a tiny eruption from Eyjafjallajökull volcano in Iceland ejected an ash plume that rose to a height of around 9 km and covered a good portion of the Northern Emisphere. Ash coverage is shown below.
An increasing portion of the community thinks that the environment and climate actually affect volcanic unrest and can even produce eruptions. It increasingly recognises small shallow overpressures as important to eruptions (Roman & Cashman, 2018). At the extreme, some researchers proposed rain produces eruptions, published in Nature (Farquharson and Amelung, 2020) and were fiercely contested (Poland et al., 2022) because they attributed eruption triggering exclusively to meteoric water and not to magma overpressure.
After 5 (five!) long years of supervising students and thus never leading a study, I published one with colleagues from the University of Salerno and INGV-Osservatorio Vesuviano, where we investigated the response of Campi Flegrei caldera (Napoli, Italy) to environmental changes connected to the long-lasting heating of our planet (De Siena et al. 2024).
The paper shows the contribution of dry and very dry (V and VD) years on the caldera's ongoing unrest: the drought between 2015 and 2020 was interrupted by a return to standard wet conditions in the winter of 2017-18. The environmental change blocked gas output at Solfatara, the main release valve at the volcano, allowing deeper materials to rise toward the surface.
The analysis was performed using standard techniques created within climatic sciences, which allowed us to recognise secondary GPS components (green arrows) that paired in space and time with seismic migrations )color-scaled arrows) during a sink in carbon dioxide emissions.
When Solfatara reopened after the sink, both GPS and seismic components rotated together, allowing a partial stress release. However, this small "breath-hold" contributed to the activation of the deeper portions of the volcano, leading to present-day seismicity.
While there is no definitive answer to how much the environment and climate affect volcanic structures and processes, the existence of an effect is indubitable: a fascinating topic for any student armed with physics and good intentions.